AU6349090A

AU6349090A - Method and apparatus for converting pressurized low continuous flow to high flow in pulses

Info

Publication number: AU6349090A
Application number: AU63490/90A
Authority: AU
Inventors: Gideon Ruttenberg
Original assignee: Developed Research for Irrigation Products Inc
Current assignee: Developed Research for Irrigation Products Inc
Priority date: 1990-09-10
Filing date: 1990-09-10
Publication date: 1992-03-30
Anticipated expiration: 2010-09-10
Also published as: AU653138B2

Description

METHOD AND APPARATUS FOR CONVERTING PRESSURIZED LOW CONTINUOUS FLOW TO HIGH FLOW IN PULSES BACKGROUND OF THE INVENTION Most trees in the world require very small amounts of water per day. If water to the tree would be supplied over 24 hours period every day, a very Small flow would be required for each tree to supply its needs.In order to develop a good root system and to allow the ground to store water for the tree, water to the tree should be supplied in such a way that a large wetted area would be created next to the tree. Commonly used systems cannot wet a large area next to the tree by using such a small flow as described. A much higher flow per tree is required with those systems in order to create a large wetted area. This is what makes all such systems complicated and expensive. It requires large size pipes and numerous valves to control the system. By using the method and apparatus described in this invention, a spray means can spray water and wet a large area next to the tree by using a very small flow. An irrigation system using such a device will be able to supply to each tree a very small flow which is much smaller than required by conventional drip or mini-sprinkler systems, and create a large wetted area next to the trees. Some of the prior art systems described in my U.S. Patent No. 4,938,420 utilize a device which converts low pressurized flow to high, non-pressurized flow, consisting of a non-pressure container and a syphon tube. Water is supplied to the container at a low flow. When water accumulating in the container reaches a certain level in the container, it flows out by gravity, through the syphon, at a very high pulsating flow to wet a large area next to each tree. The same problem as described is typical to any type of irrigation systems for any type of plants. Shower heads are designed in such a way that water is ejected at relatively high velocity over a large designated area. In order to do it a common shower head has to use a very high flow of approximately 120-180 gallons of water per hour. As a result, the water supply system should be designed to supply this high flow. Because of the high flow, the amount of water used for every shower is very high.

Instant warm water shower heads consists of heating element connected at the inlet to the shower head. Because of the high flow of water passing through the shower head, relatively high power heating elements and large amount of energy are required.

Drip systems requires emitters with low flow, when a perforated tube is used as a dripline in order that the flow through each perforation will be low, the size of the hole should be very small and such small holes are easily plugged and for practical reasons can not be used for irrigation.

Driplines installed under the ground surface are getting plugged up as a result of roots that penetrates the opening of the drippers.

At the end of each irrigation cycle, when the drip tubes drains, a vacuum may create at different locations along the tube which can cause sand particles to enter the dripline and plug the drippers. Self cleaning filters consist of a screen or other filter means as well as hydraulic valves controlled by a controller actuated by a pressure sensor or by a timer, causing the fluid to change its flow direction and flush the filter. Self cleaning filters consist of many parts and operating and maintaining the filters requires highly trained technicians.

Most self cleaning filter systems require at least two filters, because the filtered fluid of one filter is used to flush the second filter. A self cleaning gravity type filter consists of a screen and a rotating sprinkler which ejects water on the screen and flushing it, the rotating sprinkler requires a high flow of water to flush the screen.

Injection pumps in which the energy of one fluid is used to pump a second fluid, are used for various applications.

For example pressurized air is used to pump irrigation water. It is also used to pump and inject fertilize into irrigation systems. Frost damage in agriculture is the cause of a great economic losses. Different types of frost protection equipment are used from water sprayers to heaters. Most of the systems have limited results at specific conditions.

The failure of frost protection methods results from the fact they target an unconfined volume. Heaters may provide enough heat to eliminate the temperature in a citrus grove from dropping below a critical point, yet light winds may carry the warm air away and replace it with cold air. Pop up sprinklers are used mainly for irrigating lawns. The flow of pop up sprinklers is relatively high and this results fromthewaytheyaremade.

Valves and hydraulic valves consist of many parts which make them complicated, expensive, and difficult to install and maintain. Solid particles trapped at the sealing point of the valves may cause them to mal function and as a result they have to be installed in such a way that they could be easily maintained, service or replaced and this by itself makes the valves assembly more complicated.

Receptacle and pressure containers are commonly used for storing different fluids. Some materials may be spoiled when coming in contact with air. Adhesive materials fo — examples,paints etc. will become dry. Soda, namely Coca- Cola stored in a 2 liter bottle is loosing some of its properties after the bottle is opened and the bottle is not full. In such a case some of the carbonated gas flows from the liquid to the space created above the liquid reducing the concentration of carbonated gas in the liquid.

Aerosols are pressure containers in which a special enertic gas is ejected into the container by which the liquid stored in the container is pressurized. Some gases used for this purpose is creating the Ozone layer problem.

Flow controls are being used for providing a constant flow of fluid which does not change when the pressure in the fluid supply system is changing. Flow controls are being used in irrigation to control the flow through sprinklers and other irrigation devices.

They are being used to control the flow through shower heads. They are also used for controlling the flow of different fluids used for industry and medical applications. Such flow controls consist of elastic member with an orifice which in respond to pressure changes a deformation in the elastic member is created causing the cross section of the orifice to decrease, at high pressure or to increase at low pressure.

A flow control for a low flow, such for example as being used to control the flow of drippers, has a very small orifice which becomes even smaller in respond to pressure increase. Such a flow control is very sensitive to plugging.

Small changes in the orifice size, such for example resulting from production tolerance, or when used with abrasive liquids, namely irrigation water which contains sand, will cause relatively large variation in the flow through the device and as such the device can not serve properly.

Drippers consists of a long tube or labyrinth through which water flows at a low rate. Such drippers where developed in order to increase the cross section opening through which the water flows and as such for any nominal flow the opening cross section is much larger than the opening cross section of a regular nozzle or the size of a perforation in a tube. A flow control having a construction similar to that of a dripper in which a long tube made of elastic material is changing its dimension in respond to pressure changes will have a larger opening cross section than a flow control with an orifice and will be more accurate. SUMMARY OF THE INVENTION

This invention relates to a device and method for converting pressurized low continuous liquid flow to pressurized high intermittent flow. The pressurized hydraulic transformer (P.H.T.) which is describe herein is useful in any application in which low continuous flow can be converted to higher rates of flow in pulses in a continuous repetitive manner.

Although liquid flows out from the P.H.T. at a high rate in a small fraction of time in each pulsating cycle, some properties that are related to high rate of liquid flow can be achieved by using low flow.

It further relates to a method and apparatus for distributing liquid to a large designated area with a low flow, using a spray device that in regular conditions will need a much higher flow.

In one preferred application,this invention relates to a device, such as a minisprinkler, that under regular operating conditions will spray liquid to a certain designated area by using a flow Q.l and using the P.H.T., the same spray device will spray liquid to the same or larger designated area, using a much smaller flow Q.2. When liquid is being ejected from such a device, its instant flow is Q.l and it is being ejected during-a^—short time^"t^{" ~} of a cycle time T, in such a way that its actual flow is: Q.2 = Q.l x t/T. For example, if a regular minisprinkler having a flow Q.l = 8 G.P.H. is forced to pulsate so that it will eject liquid 1 second (t) every 4 seconds (T) , its actual flow Q.2 will be 2 G.P.H. ,yet, since its instant flow during the spray portion of the cycle is at the rate of 8 = G.P.H.,it will spray water to the same distance as a mini-sprinkler having a flow Q.l= 8 G.P.H. Operating at the same pressure but actually using only 2 G.P.H.

As described herein and shown in the drawings, such a device includes the following elements:

A. A pressure compensated dripper, or other means that will be described, which is fed from a liquid supply tube and discharging low continuously flow to a receptacle container. B. A receptacle container, such that pressurized liquid flowing into it will cause it some deformation that will allow its volume to be increased due to pressure increase within the container. Different forms of such containers will be described. C. A pre-set pressure responsive valve designed to open itself at a critical pre-set pressure P.l. Different types of such pre-set valves can be used. Such valves that have elastic sleeve which responds to pressure differential, will be described in detail. Such valve has a quick response which is used to create a "Water Hammer" that increases the pressure and the velocity of the ejected liquid.Such a valve has also perforations in its casing, by which, fluid can flow into the casing of the valve, mixed and eject with the liquid that flows through the valve operating as a fluid driven injection pump. D. A small size tube, or other means which will be described that create a resistance to the flow or back pressure on the valve, which forces the valve, when it opens due to pressure, to become widely open and allow for relatively high flow of liquid to flow from the container through the valve and the resistance. For example, liquid may flow from a liquid supply tube through a compensated dripper (A) to a receptacle container (B) , at a controlled low continuous flow Q.2. As liquid accumulates in the container (B) , the volume and pressure in the container (B) is increased to a critical pressure P.l. at which the pre-set valve (C) connected to the container's outlet opens. Liquid than flows from the pressure container (B) through the valve (C) and a resistor (D) , at a low flow Q.2 and as a result of the pressure drop dP created in the hydraulic resistance, in order that the liquid will continue to flow, the pressure in the container has to increase from P.l to P.2 and P.2 = P.l + dP. In response to pressure P.2 the pre-set valve (C) is forced to become widely open and liquid at a high flow Ql ejects from the container. While liquid flows to the container (B) , through dripper (A) , at a low flow

Q2. As a result, the volume of liquid in the container (B) will be decreased by DV=(Q1-Q2)t, the pressure in the container (B) will be decreased below P.l and the pre-set valve (C) closes the outlet from the container (B) .

Liquid will continue to flow through dripper (A) to the container (B) increasing volume and pressure within the container (B) and a new pulsating cycle will begin. The Quick action of the pre-set valve which causes the outlet from the container to be quickly shut off, creates a "Water

Hammer" which causes pressure to drastically increase.

"Water Hammer is the well-known term used to express the resulting shock caused by the sudden decrease in the motion or velocity of fluid. Thus, the increase in pressure caused by the sudden closing of an outlet, i.e., a valve or the like, will cause a sudden increase in pressure. This effect is utilized in the system described herein.

The "Water Hammer" phenomenon is described further in numerous publications, for example, in " McGraw - Hill, Encyclopedia of science and Technology, 5th edition, Vol.14, page 500-501."

As a result, when a sprinkler is connected to such a device, the sprinkler throws water to a larger diameter then the same sprinkler operating at a higher flow and at same pressure without the P.H.T. When a liquid flows through a pipe which is made from non-elastic material and the liquid is water at a temperature of 60 F., as a result of "Water Hammer," the pressure increase P (in PSI) will be:

P = 65V, where V is the velocity of the liquid in feet/sec.

When using elastic material, the pressure increase due to the "Water Hammer" effect will be: P = 65V 1

1 + K _κ_modulus of water (E.W.) diameter of pipe - D modulus of pipe material (E.M.) wall thickness of pipe -W OR

When the device is made of very elastic material, which means small E.M., K will be large and pressure increase will be small. In order to achieve the "Water Hammer," the device should be made from rigid material or one with low elasticity.

By way of example, in the case where the outlet conduit

(D) comprises a rigid tube having a length of 6" and an

I.D. of 0.080", where the flow to the container is at the rate of 2 G.P.H., the pre-set valve will open and close rapidly creating "Water Hammer" effect and produce frequent rapid pulses at the rate of about 10 pulses per second with the result that using a finger jet type of spray nozzle with orifice of 0.040" which would normally spray water to a diameter of 6• , by using the device it will spray water to diameter of 25'.

The volume of liquid ejected at each pulse, dV, depends on a few factors. These are the size of container (B) , its elasticity, the critical pressure PI of the pre-set valve, etc.

One way of increasing the amount of liquid ejected at

shape that allows its volume to be increased without changing its circumference. Such a container can be produced from a rigid material that has a very small flexibility and would generally be one which is a rectangular transverse cross section.

Such a container, for Example, can have a square cross section of 1" x 1", horizontal circumference of 4" and a cross section area of 1 square inch and a predetermined length. If the pressure in such a container will force its cross section to become circular, its circumference will still be 4" and its cross section will increase to 1.27 square inches, which means an increase of 27% in volume can be achieved with such a container without changing its circumference.

Such a container, made of a rigid material and having such a geometric shape, will allow its volume to be increases due to pressure changes, and still maintain the possibility of creating "Water Hammer." For certain applications, a container formed of material having a desired degree of resiliency may be used.

Another possibility of increasing the ejected amount of liquid in each pulse is by using trapped air in the container.

Pressure changes in the container will cause trapped air to contract and expand, thus increasing the ejected amount of liquid. Since air might be dissolved in the liquid, and thus escape from the container, the air can be trapped in a small secondary container, for example, a small, hollow, flexible ball installed in container (B) . Pressure increase in container (B) will cause the ball to contract and allow for more liquid to be accumulated in container

(B) before it will be ejected.

In order to force pre-set valve (C) to become widely open, a resistance to the flow can be created downstream from the pre-set valve. The magnitude of such resistance depends on a few factors and mainly on the properties of the preset valve (C) and the inlet flow Q2 to the container (B).

The resistor (D) should be such that it will create enough resistance to the inlet flow Q2 to force preset valve (C) to widely open, yet it should be as small as possible to create minimum resistance to the high ejected flow Ql from container (B) . The resistance can be hydraulic resistance created by friction lose due to a liquid flowing through a small size diameter tube, or a small orifice. It can be created due to elevation difference between a spray nozzle and the preset valve

(C) , and it can be a mechanical resistance created by an obstacle, for example, a floating ball installed in the path of flow between the outlet of the preset valve (C) and the spray nozzle, or it can be a combination of such factors.

When the perforations in the pre-set valve are surrounded by air, a mixture of liquid flowing through dripper (A) and air flowing through the perforations in the preset valve (C) will be ejected through tube (D) .

When perforations in pre=set valve (C) are surrounded by a second liquid namely liquid fertilizer, a mixture of liquids consisting of one liquid flowing through dripper (A) and a second liquid flowing through perforations in the casing of preset valve (C) will be mixed and ejected through tube (D) .

When such a device is installed in a container in which a second liquid is being stored, as long as the level of the second liquid within the container is higher than the level of the perforations in the pre-set valve, a mixture of the two liquids will be ejected through tube (D) . When the level of the second liquid in the container is at or below the level of the perforation in the pre-set valve (C) , a mixture of liquid from dripper (A) and air from the container will be ejected through tube (D) .

By adjusting the level of preset valve (C) in the container of the second liquid, the total amount of second liquid that will be ejected in each operation can be controlled.

When the pressure in the liquid supply system is kept below the critical pressure PI of the preset check valve (C) , the outlet from container (B) will stay closed, and liquid will not be able to drain from pressure the receptacle container (B) , which means, by reducing the pressure in the liquid supply system below the critical pressure PI of the preset valve (C) we can prevent the system from draining at the end of each operation. The pre-set valve (C) can be designed to have different critical pressures PI. For example, one group of pre-set valves can be designed to have a critical pressure of PI = 20 PSI and a second group can have a pre-set valve with critical pressure PI = 40 PSI. If the two groups are connected to the same liquid supply system, they can be operated as follows:

When pressure in the liquid supply is lower than 20 PSI, no liquid flows out from the system. . When pressure in the liquid supply system is higher than 20 PSI and lower than 40 PSI, liquid will flow out from the system only through group one. When pressure in the system is higher than 40 PSI, liquid will flow out through the two groups. Each, a few, or all features of P.H.T. can be used in different applications, some of which are described below.

As an example I have designated a Pulsating Compensated Non-leaky Minisprinkler (P.C.N.M.) as shown in Fig. 1 and as described below. Such a device includes:

A. A pressure compensated dripper.

B. A receptacle container having a form of a spike.

C. A preset pressure responsive valve having perforation in its casing and has a quick response. D. A small size inside diameter rigid tube. E. A spraying device. This P.C.N.M. unit has the following features:

It can be operated at a very low flow, namely Q2-

2G.P.H. . It will wet a very large area, namely, a wetted area having a diameter of 20'.

Its flow is compensated. It will spray the same flow regardless of the pressure in the irrigation tube.

Its spray nozzle will be relatively large, namely 0.060", which will eliminate its plugging.

It will eject water and air and this too can eliminate plugging of the spray nozzle.

Due to "Water Hammer" water will be ejected at a very high velocity. When pressure in the irrigation tube will be decreased below the critical pressure PI, namely, below 20 PSI, by shutting off the main valve, the water in the irrigation pipes will not drain, and the system will stay full.

Two groups of such P.C.N.M. units can be connected to the same irrigation system. One group having a low PI, namely, Pl=20 P.S.I. , may be used for irrigation and the second group of P.C.N.M. having a higher pre- set pressure P.l = 30 P.S.E units will be operated only in emergency by increasing the pressure in the system.

One preferred pulsating device is a Normally closed pulsating valve formed in such a way that the three basic elements of a pulsating device: a. the receptacle b. the preset normally closed valve c. the hydraulic resistance are created in the pulsating valve itself. Such a Pulsating valve consist of one pre-set pressure responsive normally closed "valve" created at its inlet and a second pre-set pressure responsive normally closed "valve" created at its outlet and a receptacle container is created in the Pulsating valve between the two "valves". The second "valve" being normally close is serving also as the hydraulic resistance described before and additional resistance can be created if needed within the Pulsating valve or downstream from the normally closed "valve" at the outlet as part of the Pulsating valve by using the same means described before or by connecting such means at the outlet from the Pulsating valve. The invention describes also a preset pressure responsive Normally open pulsating valve consisting of elastic tube enclosed in a casing. The space surrounding the elastic tube is connected to the inlet of the valve and as such the pressure of the fluid at the inlet to the valve and at the space surrounding the elastic tube are the same. When a fluid flows through the elastic tube, a pressure drop is created along the tube, the pressure inside the elastic tube decreases, and the pressure surrounding the elastic tube is casing it to contract and become flat preventing from the fluid to flow through the tube. Since at no flow there is no pressure drop, the pressure inside the elastic tube increases the valve opens,terminating one pulsating cycle.

- A Pulsating dripline which consist of perforated tube or any type of dripline connected to the water supply system by means of a pulsating device can have drippers or perforations with a very large opening operating at a very low flow.

- The invention describes a Frost control method by which an item that need protection is enclosed in a sheath that is wetted by means of a pulsating minisprinkler. The pulsating minisprinklers sprays water at very low rates on the sheath and a small layer of water is retained by the sheath. At low temperature the thin layer of water is converted to ice, creating an "Igloo" which isolates a designated small volume surrounding the item that need protection. Such an item can for example be a plants.

- The pulsating valve can operate as a an Injection pump as was described and it can also function is a Fluid driven pump.

When a main fluid flows through the valve and causing it to pulsate, the elastic member of the valve contracts and expands. When the elastic member contracts,a second fluid can enter the casing of the valve through one port and when the elastic member expands, it is pressed against the port in the casing sealing it and pressing the second fluid against the inner walls of the casing thus pressurizing the second fluid and forcing it to mixed and eject with the main fluid through the outlet of the valve (as was described before) or to eject separately at elevated pressure through a second port in the casing. - One special application of the fluid driven pump is a Soaping device which is created by connecting a container with liquid soap to the second fluid outlet of the pump. The device is connected to a faucet and when water flows through the valve causing it to pulsate, air enters the casing of the pump and flows through the liquid soap converting it to foam which than mixed and ejects with the water.

- A Self cleaning filter is a pulsating valve in which part of the elastic member of the valve,which creates the receptacle container, is perforated. A fluid namely water flows from the inlet of the valve through the

"screen" created by the perforated elastic member, out through a port in the casing.

When the screens plugged up, the screen than becomes a receptacle container, the filter is converted to a pulsating valve and fluid from the receptacle container ejects at a high pulsating flow through the outlet of the valve flushing the screen.

- The invention describes a Self cleaning low flow pulsating pop up sprinkler in which the sliding guide of the Pop up is a screen that is being automatically flushed at each new irrigation cycle and a pulsating valve is connected between the riser and the sprinkler head. - The pulsating valve can be used for operating Rotating sprinklers such which are being used for example to irrigate row crops at a low flow.

- The pulsating valve can be produced also with a Deflector being part of the pulsating valve itself controlling the pattern of the ejected fluid.

- A Flow control can be installed inside the pulsating valve at its inlet portion.

- By connecting a normally closed preset pressure responsive valve to the outlet of a normally open preset pressure responsive valve, a new type of valve is created which is Limited pressure range valve that opens only at a limited range of pressures at the inlet to the valve which is the preset pressure P.l at which the normally closed valve opens and the preset pressure P.C at which the normally open valve closes itself.

- A Fluid control method and apparatus is described in which, by using different combinations of normally closed, normally open, and limited range valves, different outlets from the same fluid supply system can be controlled and operate separately in response to pressure changes in the system.

- A Low flow pulsating shower head is described which consist of a shower head connected to the outlet of a pulsating valve can be operated with a relatively very low flow of water saving water and heating energy.

- An instant warm water low flow low power and low energy pulsating shower head is described which consist of a shower head connected to the outlet of a pulsating valve in which the water flows through a heating element can provide instant warm water by using a low power and heating energy and operate at a higher efficiency resulting also from the high velocity jets that flows in the air with minimum heat losses. - A group of pulsating shower heads as descried may include cold water pulsating shower heads, warm water pulsating shower heads and soaping devices as described connected to the same pipe and controlled separately in response to pressure changes in the pipe. A normally closed pulsating valve with a relatively high preset pressure connected to the system can serve as a pressure relief valve, serving as a safety device.

- A domestic, industrial or commercial water supply system may consist of a group of different heating elements, concentrated in one or more locations, actuated in different combinations in response to different requirements for warm water, that flows through different typesofvalvesasdescribedhavingdifferentpresetpressures. During the development of the pulsating valve, new innovated valves, receptacle and flow controls were developed. Those items are described too in this invention and are claimed as new innovated inventions independently from the main claims of pulsating devices and their directly related applications.

- Normally open valves and hydraulic valves and Normally closed valves and hydraulic valves which are produced in a simple way and consist of elastic tubes which surrounds an insert and inclosed in a casing. The different functions of the valves is achieved when the elastic tube is exposed to pressures from different controlled locations which in response are causing deformations in the elastic tube causing it to expand or contract and thus closing or opening the different valves. Although some Hydraulic valves commonly used in the market contain elastic members, the elastic members in those valve are being used mainly as sealing materials in which a rubber like material is pressed against a solid member, serving a similar function to that of an "O ring". Furthermore, additional fittings and part are being used in such valves for holding the elastic member at a fixed place.

- A Normally open valve according to this invention consists of elastic tube installed around an insert having a fluid inlet and a fluid outlet having a larger outside diameter formed as a barb by which the elastic tube at both of its ends is held at a fixed place by surrounding it tightly. The elastic tube and the insert are inclosed in a casing which has a port through which the space surrounding the elastic tube is vented when the valve is at its normally open position, and pressurized for closing the valve. The port can be connected directly to the fluid supply pipe and such a valve will close itself when the force F.3 created by the pressure surrounding the elastic will become larger than the force F.l created on the elastic tube by the pressure inside the elastic tube and the force F.2 which is the resistance of the elastic tube to- contract and become flat.

The valve will close itself when F.3 > F.l + F.2. In such a case the valve will close itself when the walls of the elastic tube are pressed against each other or against a center rod inside the elastic tube which is part of the insert.

The same valve can operate as a Normally open hydraulic valve when the pressure at the port is controlled by a valve namely a solenoid valve which can be remote controlled.

- Normally closed valve according to this invention consist of an insert having a fluid inlet and fluid outlet and openings at the inlet and outlet through which a fluid can flow from the space inside the insert to the space outside the insert. The elastic tube is held at fixed place by surrounding tightly both sides of the insert which has at this location a larger outside diameter. The elastic tube surrounds tightly the center section of the insert or at least a portion of it and surrounding tightly the openings at the inlet and or outlet from the insert. At the normally closed position of the valve the elastic tube surrounds tightly the opening at the insert eliminating from the fluid to flow from the inlet to the space surrounding the insert.

When the pressure of the fluid at inlet is high enough, the elastic tube expands, its inside diameter increases, and a fluid than can flow from the inlet, through the opening, to the space created between the insert and the elastic tube and out through the opening at the outlet and through the outlet out from the valve. The normally close pre-set pressure P.Q at which the elastic tube expands and allowing the fluid to flow from the space inside the inlet to the space surrounding the insert depends on a few factors:

* The outside diameter of the insert at the closing cross section.

* The inside diameter of the elastic tube, its wall thickness and its physical properties.

When the insert is made with one size outside diameter at the inlet and another size at the outlet the valve has two pre-set normally closed valves one at the inlet and a second at the outlet.

Receptacle according to this invention consists of an insert surrounded tightly by elastic tube in a similar construction to the normally closed valve described above. Such a receptacle has one or two normally closed valves. When the device has two normally closed valve, when a fluid is injected through the inlet at the insert at a sufficient pressure higher than the pre-set pressure P.0/1 at the inlet, the fluid flows from the inlet, through the opening at the inlet to the space surrounding the insert and enclosed by the elastic tube.

The fluid will continue to flow to this space increasing the volume of the stored fluid and its pressure. When the pressure of the fluid at the space is slightly lower than the pre-set pressure P.0/2 of the normally closed valve at the outlet, the injection of the fluid through the inlet terminates. At this stage a volume V.O of the fluid is stored in a receptacle which is created by the fluid itself. Such a receptacle has the following properties:

* No fluid can enter the container through its inlet or its outlet unless its pressure is higher than the pre-set pressures P.0/1 at the inlet or P.0/2 at the outlet.

* The volume of the container is increasing when the volume of the fluid stored is increasing and the volume of the container is decreasing when the volume of fluid it stores is decreasing.

* When the container is empty, the container has no volume!

* The fluid in the container is pressurized at any stage including the stage in which it stores "one drop of fluid."

* The fluid will be ejected from the container only when its pressure will increase and become higher than the pre-set pressure P.0/2 at the outlet. * The pressure of the fluid inside the container can be increased by pressing on the elastic tube, namely by squeezing it.

The invention describes three types of such receptacle. Flow controls according to this invention consist of elastic tube held at a fixed place by surrounding tightly a larger outside diameter of a fluid inlet fitting and a fluid outlet fitting. The elastic tube is enclosed in a casing and the devise is made in such a way that the space surrounding the elastic tube is connected by means of a port to the inlet fitting and as such thf. fln-iri has hp same pressure P.2 at the inlet to the elastic tube and at the space surrounding the elastic tube. When a πuiα πows from the Inlet through the elastic tube at a nominal flow, no or negligible deformation is created in the elastic tube. When the pressure P.2 at the inlet increase, as a result of higher flow through the tube, a pressure drop dP is created along the elastic tube causing the pressure inside the elastic tube to decrease from P.l = P.2 - P.l t, the pressure surrounding the elastic tube P.2 is now higher than P.l, the elastic tube contracts, its inside diameter decrease and the flow through the elastic tube decreases back to its nominal rate.

The device can be made so that all or substantial length of the elastic tube will decrease its inside diameter in response to pressure increase at the inlet.

Some of the valves described above consist of elastic tube enclosed in a casing can be produced can be produced as one part which consist of one tube inside another tube the outside tube in such a case is serving as a casing.

The insert and the elastic tube of a normally closed pulsating valve (9) can be,with minor changes, installed inside a plastic tube which is serving as a casing for the device. This can be done automatically during the extrusion of the plastic tube ( two heads extruding machine) . The end product is a dripline in which the water from each "dripper" ejects from the tube in pulses according to the method described above.

Normally closed valves.sprayers, drippers and driplines made of perforated elastic tube. The perforations in such a tube stays closed when the pressure inside the elastic tube is low and at a higher pressure the elastic tube expands,its inside diameter increase and as a result the perforations open. The perforated elastic tube serves also as a receptacle. A volume dV of fluid is accumulating in the elastic tube when the pressure inside the tube is increasing from P.O ,at which the perforations are closed, and P.l where they opens. An hydraulic resistance can be created at the outlet of the perforations and as such the perforated elastic tube can by itself become a pulsating device according to the method described above in which a pulsating device consist of: a receptacle,normally close pressure responsive valve and hydraulic resistance.

Normally closed elastic perforated dripline tube has the following advantages:

- When not in operation the perforations in the tube stays closed, eliminating from roots to penetrate.

- At the end of each irrigation cycle the tube stays full of water. No vacuum is created along the tube,and sand particles are not sucked into the tube.

- By increasing the pressure inside the elastic tube,its inside diameter increase and the tube can than carny a higher flow.

- By increasing the pressure inside the elastic tube,the size of the perforation can be increased substantially and by periodically increasing the pressure inside the tube plugging of the perforations can be eliminated.

- A pulsating valve as described above (9) connected at the inlet of such a dripline can be used in order to reduce the flow through the perforations.

- The perforations in the elastic tube can be made in such a shape, that each opening will be a flow control by itself and the flow through each perforation is the same regardless of the pressure inside the elastic tube.

- The dripline as described can be made of elastic materials and it can be made of plastic materials with short sections of elastic perforated tube connected to the plastic tube.

- Similar results can be achieved by surrounding the perforations of a plastic tube with elastic perforated sleeve or by connected elastic members to the perforations of a plastic tube.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view partly in cross section showing a pulsating minisprinkler operating with the method described above. Its receptacle is made in the form of a spike for inserting in the ground. It operates at a very low flow, wetting a large area.

Water is ejected from the spray device at a very high pressure due to a "Water Hammer" created by the quick responses of the preset pressure response valve. It ejects water and air which is sucked through perforation in the casing of the valve.

Fig. 2 is a cross section showing one type of a preset pressure response valve utilized in the practice of this invention. Such a preset valve has a quick response and it has perforations in its outer casing, which are used for sucking fluid from its surroundings, mixing and ejecting it similar to the operation of a venturi pump.

Fig. 3 is a view partly in cross section corresponding to Fig.l showing the receptacle of Fig. 1 divided into two sections mounted directly upon the liquid conduit.

Fig. 4 is a view partly in cross section showing a section of a flexible conduit forming the liquid receptacle upon which the valve and spray unit are mounted.

Fig. 5 shows the identical structure of Fig. 1 except that a secondary container containing trapped air is positioned within the receptacle.

Fig. 6 is identical to Fig. 1 except that a compensating dripper is replaced by a small nozzle.

Fig. 7 is identical to Fig. 1 except that provision is made for the insertion of a mechanical obstacle in the outlet of the valve for example using a movable ball as shown. Fig. 8 shows the pumping action of the valve.

Fig. 9/1 illustrates in cross section a normally closed pulsating valve with a deflector connected to the insert in which: la shows the valve at its normally closed position lb shows the valve at its open pulsating position.

Fig. 9/2 illustrates in cross section normally closed pulsating valve with a deflector being part of the valve in which:

2a shows the valve at its normally closed position. 2b shows the valve at its open pulsating position.

Fig. 9/3 illustrates in cross section a normally open pulsating valve of another type with the valve at its pulsating position.

Fig. 10 illustrates in cross section a self cleaning filter valve in which:

10a shows the valve at its filtration stage and 10b shows the valve at its flushing stage. Fig. 11/1 illustrates in cross section an injection pump incorporating the novel valve structure in which: la shows the pulsating pump at its closed position and lb shows the pump in its pulsating and pumping stage. Fig.11/2 illustrates in cross section another type of a pump consisting of a pulsating valve with two ports in the casing in which:

2a shows the pump at its closed position and 2b shows the pump at its pumping stage. Fig. 11/3 illustrates in outline the injection pump 11/1 in operation pumping water from a reservoir. Fig. 11/4 illustrates in outline another similar pumping operation.

Fig. 11/5 illustrates in cross section a soaping device incorporating a pump constructed according to Fig. 11/2.

Fig. 12 illustrates in outline different types of pulsating sprinklers and drippers which incorporate the novel pulsating valve structure, connected in different ways to laterals.

Fig. 12/1 is a view of a pulsating spray head connected to a rigid riser. Fig. 12/2 is a view of a pulsating spray head connected to a pipe with its outlet below the inlet.

Fig. 12/3 is a view of a pulsating spray head connected to one flexible tube by means of another flexible tube and a rigid rod which supports the pulsating spray head. Fig. 12/4 is a top view of a pulsating rotating sprinkler.

Fig. 12/5 is a view showing a drip perforated tube connected by means of a pulsating valve to a lateral.

Fig. 13 illustrates in outline a frost control system which utilizes a pulsating spray over a foraminous protective enclosure.

Fig. 14 illustrates in cross section a self cleaning low flow pulsating pop-up sprayer which incorporates the novel pump structure described herein. 14a shows the pop-up sprayer at its low, closed position.

14b shows the pop-up sprayer at its rising stage. 14c shows the pop-up at its high, open position. Fig. 15 illustrates a method and devices for controlling different outlets connected to the same pipe and operate separately by changing the pressure in the pipe.

Fig. 15/1 shows a limiting valve consisting of a normally open valve 9/3 (with a center rod as described or without it) with a preset closing pressure P.C. and a normally closed valve 9/1 with a preset opening pressure P.O lower than P.C connected to the outlet of valve 9/3. Such a limiting valve allows fluid to flow through only at limited pressures higher than P.O and lower than P.C. Fig. 15/2 is a schematic drawing showing a system consisting of 6 groups of outlets connected to the same pipe and operating separately by changing the pressure in the pipe. Normally open valve, limiting valves, and normally closed valves are connected to each outlet and controlled separately in response to pressure changes in the pipe.

Fig. 16/1 illustrates a view in cross section of a normally open hydraulic valve in which:

16/la shows the valve at its normally open position and

16/lb shows the valve at its closed position. Fig. 16/2 illustrates a view in cross section of another type of normally open hydraulic valve with a center rod connected to the inlet and outlet fittings of the valve by means of ribs inside the fittings in which:

16/2a and 16/2b show open and closed positions respectively.

Fig. 17 illustrates a normally closed hydraulic valve in cross section in which: 17a shows the valve at its normally closed position and

17b shows the valve at its open position. Fig. 18 illustrates a normally, closed preset pressure responsive valve in cross section in which:

18a shows the valve at its normally closed position 18b shows the valve at its open position. Fig. 19 illustrates a normally open preset pressure responsive valve in cross section at its normally open position.

Fig. 20 illustrates a normally closed preset pressure responsive spray head valve with a deflector connected to the outlet of the valve in cross section in which:

20a shows the valve at its normally closed position and

20b shows the valve at its open position. Fig. 21 illustrates a normally closed preset pressure responsive spray head with a deflector as part of the valve in cross section at its normally closed position. Fig. 22/1 illustrates in cross section one type of flow control valve.

Fig. 22/2 illustrates in cross section another type of flow control valve.

Fig. 23/1 illustrates in cross section one type of expandable receptacle or container in which:

23/la shows the container at its normally empty position and

23/lb shows the container full with pressurized fluid. Fig. 23/2 illustrates in cross section another type of expandable container in which :

23/2a shows the container at its normally empty position and

23/2b shows the container full with pressurized fluid. Fig. 23/3 illustrates in cross section still another type of expandable container in which:

23/3a shows the container at its normally empty position and

23/3b shows the container full with pressurized fluid.

Fig. 24/1 illustrates a normally closed perforated elastic tube serving as a dripline for irrigating trees.

Fig. 24/2 illustrates a normally closed perforated elastic tube serving as a dripline for irrigating trees, vegetables, and any other type of plants.

Fig. 24/3 shows in cross section one example of a perforated elastic tube in which the flow through the perforation is pressure compensated and the flow through each perforation along the tube is the same.

DETAILED DESCRIPTION OF THE DRAWINGS Fig. 1 illustrates one preferred form of minisprinkler device operated with the P.H.T. method and formed for direct insertion and support in the soil adjacent to a tree or another area to be irrigated. A receptacle is in the form of a spike 1 having a sharp point la for ground insertion and enclosing a hollow chamber 2 having a square cross section for retention of water. The shape and dimensions of the container are determined by the particular application and can be of any practical volume. As a spike for insertion in the soil a practical dimension would be as a rectangular cross section 1" x 1" with a length of 6" - 12". It is formed of a suitable rigid material, preferably of rigid, molded plastic, such that pressure increase within its hollow space will cause it to become slightly rounded and thus increase its volume.

The container is provided with an inlet opening 3 and outlet 4. The inlet opening is fitted with a compensating dripper or other flow control device 5 which is in turn connected to a hose or tube 6 of suitable length for connection by means of a fitting 7a to a water supply pipe 7.

The outlet is connected to a preset pressure responsive valve 8 of the type illustrated in Fig. 2. This is then connected by means of tube 9 having a small diameter bore

9a to a spray means 10 in which water is pulsed through nozzle 10a against a deflector 10b.

The spray means may be of any suitable type such as a finger spray or a rotary spray or like where a large diameter spray area is desired.

A preferred type of preset pressure responsive valve 8 which is especially effective in being quickly responsive to fluctuations in pressure is illustrated in Fig.2. Fig. 2 illustrates the structure of such preset pressure responsive valve 8 which includes three parts: an outer casing 11, an insert 12 and an elastic sleeve 13 made of rubber or the like, which surrounds and fits snugly the outside wall of insert 12. The outer casing and the insert are preferably formed of plastic material. These are concentric and preferably cylindrical. Insert 12, as shown, is in the shape of an inverted cup like member open at the bottom with its side walls surrounded by and engaged by sleeve 13. Elastic sleeve 13 is formed with a rib 13a, which is engaged in a slot 14 made in the insert 12, which is formed with a widened portion at the bottom to accommodate the slot and engage the rib portion of the elastic sleeve. Also, the angular flat portion 13b of the sleeve, as shown, serves as a gasket between outlet casing 11 and insert 12. The bottom portion of 12 which is not engaged by the sleeve is cemented or force-fitted to the bottom portion of casing 11 as shown. Casing 11 and insert 12 are made of rigid material and are cemented together and provide a liquid inlet 15 and outlet 16.

Insert 12 has one or more perforation 17 in its side wall. When liquid pressure inside the insert 12 is at or below a critical pressure PI the openings will be enclosed by elastic sleeve 13 which surrounds the insert tightly. When pressure of liquid within the insert 12 is increased above a critical pressure PI, the pressure forces elastic sleeve 13 to expand in an expanding space 18 between casing 11 and insert 12 as shown for example by dotted line 20.

Then liquid flows out from insert 12 through perforations

17, and will continue to flow between outside walls of insert 12 and inside walls of elastic sleeve 13 out through outlet 16. Perforations 19 in the casing 11 connect expanding space 18 with the external surroundings of the preset pressure responsive valve 8 allowing for fluids, namely, external air, to flow into the expanding space 18 and permitting the elastic sleeve to expand into the space. When the valve is at its close position and elastic sleeve 13 surrounds tightly insert 12, fluid namely air, penetrates casing 11 through perforations 19 filling up the space between the elastic sleeve 13 and the casing 11. When valve 8 opens and a liquid flows through the valve, elastic sleeve 13 expands, pressing against perforation 19 and against the fluid surrounding elastic sleeve 13 which its pressure is increased and it is forced to flow out through outlet 16 where it is mixed and ejects with the liquid that flows .through the valve 8. When liquid pressure in the insert 12 is reduced below

P.l, elastic sleeve 13 will return to its position, sealing perforations 17 and preventing liquid within insert 12 from flowing until liquid pressure in the insert 12 is increased again to the critical pressure PI. The pressure PI which forces elastic sleeve 13 to expand, depends on the wall thickness of the elastic sleeve and the material it is made from. A thicker wall of the elastic sleeve will increase critical pressure PI. Inlet 15 is designed to snap on the outlet 4 of spike 1 in Fig. 1. Outlet 16 is designed so that rigid tube 9 in Fig. 1 can be snapped to it.

As shown in Fig. 1 water from the irrigation tube 7 flows through hose 6 and pressure compensated dripper 5 at a low continuously controlled flow Q2 to spike 1 in which it is being accumulated and its pressure is increased to a critical pre-designed pressure PI at which elastic sleeve 13 of preset pressure responsive valve 8, which is connected to outlet 4 from spike 1, expands, and allow water to flow out from the spike 1 through preset pressure responsive valve 8 to a small sized inside diameter tube 9. Friction loss at tube 9 forces elastic sleeve 13 to widely expand, allowing for a high flow Ql of water to be ejected from spike 1 through preset pressure responsive valve 8 and tube 9. The high flow ejected from the spike flows through nozzle 10a of a spray device 10 and spreads by deflector 10b over large designated area.

While water ejects from spike 1 at a high flow Ql, it is supplied into spike 1 through dripper 5 at a low flow Q2, as a result the volume and pressure within spike 1 decreases to P2, lower than P.l and the preset pressure responsive valve 8 closes itself and closes outlet 4 from the spike 1, until more water flows from dripper 5 and accumulates in spike 1 increasing the pressure within the container to PI and starting a new pulsating cycle.

Due to the quick response of the preset pressure responsive valve 8, a "Water Hammer" is created which increases the pressure and velocity of the ejected water. When valve 8 close and opens itself, fluid namely air, flows into the casing 11 and out through the valve outlet 16 at pulses mixing with the liquid that flows through the valve.

Instead of the elastic sleeve type of valve described above, a conventional spring loaded normally closed valve may be used.

Fig. 3 describes an alternative manner of installing the device shown in Fig. 1 in which the spike container is divided into two sections lb and lc which are designed to encircle and engage the circumference of water conduit 6a which in effect passes through the container and may be engaged at spaced intervals by additional spike units of the same type. During assembly of the sections a compensating dripper 5a is inserted into opening 3a in the conduit positioned in the upper section as shown, and a controlled flow of water is passed into the chamber 2a and passed through outlet 4a into valve 8a and tube 9a as described above with respect to Fig. 1. The two sections are secured to the conduit by cementing or otherwise and to ensure against leakage a pair of gasket rings 21 may be cemented in place as shown.

Fig. 4 illustrates a pulsating minisprinkler in which the container, instead of being in the form of a spike, utilized to support a sprinkler or similar unit, is in the form of a flexible tube 22 which is connected to water supply 7 by means of a suitable fitting and in turn to a compensating dripper 24 and by means of another fitting to inlet 25 of the tube and the tube is connected at its outlet 26 by means of fitting 27 to valve 28. The function of the device is similar to that described with respect to

Fig. 1 and 2. and support for the device of Fig. 4 is provided by means of a rod 30 or similar member which is affixed at its upper end to the valve and may be inserted into the ground as shown, to elevate the tubular container. Fig. 5 illustrates a pulsating device as shown in Fig. 1 where a small receptacle 31 which is formed of semi-rigid or flexible material containing air is placed within the receptacle to permit trapped air to increase the ejected amount of liquid in each pulse.

Fig. 6 illustrates a pulsating device as shown in Fig.l, where the pressure compensating dripper of Fig. 1 is replaced by a small nozzle 56 which controls flow into the receptacle. the same use of a nozzle can be applied in place of the drippers shown in Figures 3 and 4.

Fig. 7 illustrates a pulsating device with a mechanical obstacle in the form of a ball which floats with the pressure of liquid that flows through the valve 8. The ball is incorporated within the outlet structure of the valve in Fig. 2. The ball is placed within a compartment formed by an inner ring 33 provided with an opening 34 and a fitting 35 also provided with an outlet opening 36.

Fig 8a and .8b illustrates the pumping action described above is shown with arrows in 10a showing the direction of flow of the secondary fluid, which as shown in Fig. 2 enters perforations 19 and fills space 18 confined between elastic sleeve 13 and the outer casing until such time during each pulse that the valve remains closed. When, as described above, the pressure reached the point at which the valve opens, the sleeve expands to the position shown in Fig. 8a also shown in dotted line in Fig. 2. This causes the closure of perforations 19 and forces the fluid from space 18 and out between the elastic sleeve and the casing out through outlet 16 to become intermingled with the main fluid. The secondary fluid may be gas, such as air.

When the unit is positioned to be surrounded by a liquid above the perforations, this secondary liquid will become admixed with the primary liquid thus functioning as an injection pump. When the liquid level is below the perforations that flow will cease and only air will enter through perforations 19.

Fig. 9 illustrates two types of pulsating valves by which a low continuous flow is converted to a high pulsating flow. Type A is a normally closed pulsating valve and type

B is a normally open valve.

Fig 9/1 illustrates a normally closed pulsating valve type A. The valve consists of elastic tube 9101, casing 9102 and insert 9103. Insert 9103 has a fluid inlet 9104 and fluid outlet 9105.

Casing 9102 has a port 9106 through which space 9107 surrounding the elastic tube 9101 is vented. Insert 9103 has a barb 9108 for holding the elastic tube 9101 at a fixed place. Insert 9103 has an opening 9109 which can be used for supporting the valve on a rod. Insert 9103 at its inlet 9104 has an opening in the shape of a cylinder 9110 plugged at its end 9111 and having perforations 9112 at its circumference. At its outlet 9105 insert 9103 has an opening in the form of a cylinder 9113 plugged at its end

9114 and having perforations 9115 at its circumference. Section 9116 of insert 9103 and step 9117 are made for connecting casing 9102 to insert 9103. Outside diameter 9118 of insert 9103 allows the valve to be connected with its outside diameter at its inlet 9104 to a pipe or a fitting.

Fluid inlet 9104 has also an opening in the shape of a casing 9119 for a flow control type B [please see Fig. 7/2] in which a tube 9120 can be installed for controlling the flow Q.O into the valve. Center section 9121 of insert

9103 has an outside diameter smaller than section 9108.

Section 9122 of insert 9103 has an outside diameter smaller than section 9121. Section 9123 of insert 9103 has an outside diameter larger than section 9122 and it is made for holding elastic tube 9101 at a fixed position. Section 9124 of insert 9103 is made for connecting a spraying device by fitting it to the outside diameter of section 9124 or by inserting it into its inside diameter.

Elastic tube 9101 has an inside diameter smaller than the outside diameter of insert 9103 at sections 9121 and 9122. Fig. 9/la shows the normally closed pulsating valve type A at its closed position. Elastic tube 9101 surrounds tightly insert 9103 sealing perforations 9112 preventing a fluid to flow from inlet 9104 through the valve to outlet 9105.

Fig. 9/lb shows the normally closed pulsating valve type A at its pulsating stage. When the pressure P.l of a fluid at inlet 9104 is higher than the preset pressure P.O of the valve a fluid at a low controlled flow Q.O controlled by a flow control 9120 [or by another type of flow control which can be a pressure compensated dripper, a dripper or a nozzle connected to inlet 9104] flows into cylinder 9110 at the fluid inlet 9104 of the pulsating valve. The pressure P.l of the fluid at cylinder 9110 forcing elastic tube 9101 to expand and its diameter to increase to D.l in respond to the pressure P.l. The fluid then flows through perforations 9112 to the space 9125 created between the outside diameter 9121 of insert 9103 and the inside diameter D.l of elastic tube 9101. At this stage the fluid flows at a flow Q.O through the small open cross section created at space 9125 around section 9121. A pressure drop dP is created along section 9121 and in order that the fluid will be able to continue to flow at a rate Q.O the pressure at cylinder 9110 has to increase from P.l to P.2 and P.2 = P.l + dP. In response to the to pressure P.2 at cylinder 9110 the inside diameter of elastic tube 9101 is increasing to D.2.

A volume dV of fluid accumulates between the elastic tube 9101 inside diameter D.2 and the insert outside diameter at section 9121. The large open cross section of space 9125 created between outside diameter 9121 of insert 9103 and the inside diameter D.2 of elastic tube 9101 allows the volume dV of the fluid to flow at a high rate Q.l through sections 9121 and 9122 perforations 9115 and cylinder 9113, out through the fluid outlet 9105. While fluid flows out from space 9125 at a high flow Q.l and flow into space 9125 at a low flow Q.O, the volume dV of the fluid in space 9125 decreases, the pressure in space 9125 decreases, the inside diameter of elastic tube 9101 decreases, and becomes smaller than the outside diameter of insert 9103 at section 9121. The elastic tube 9101 surrounds tightly perforations 9112 closing the fluid inlet 9104 and terminating one pulsating cycle.

Fig. 9/2 illustrates a normally closed pulsating valve type A with its outlet formed into a deflector for controlling the pattern of the ejected flow.

The valve consists of elastic tube 9201, casing 9202 and insert 9203. Insert 9203 has a fluid inlet 9204 and fluid outlet 9205. Casing 9202 has a port 9206 through which space 9207 surrounding the elastic tube 9201 is vented.

Section 9208 of insert 9203 has a large outside diameter formed as a barb for holding elastic tube 9201 at a fixed place. An opening 9209 at the bottom of insert 9203 can be used for supporting the valve on a rod. Fluid inlet 9204 has an opening in the form of a cylinder 9210 plugged at its end 9211 and having perforations 9212 at its circumference. At its other end insert 9203 is formed in a shape of deflector 9213. Section 9214 and step 9215 of insert 9203 are made for connecting casing 9202 to insert 9203. Section 9216 of insert 9203 has an outside diameter that can be used to connect the valve with its outside diameter to a pipe or a fitting. Fluid inlet 9204 has also a space 9217 which can be used for installing a flow control type B in which a tube 9218 or the same can be installed inside insert 9203 for controlling the flow of fluid Q.O into the pulsating valve.

A flow control, a dripper, a pressure compensated dripper or any type of means for controlling the flow of a fluid into the pulsating valve can be connected to the fluid inlet 9204 either by connecting it to the outside diameter of section 9216 or by its inside diameter. Center section 9219 of insert 9203 has an outside diameter smaller than section 9208. Section 9220 of insert 9203 has an outside diameter smaller than section 9219.

Elastic tube 9201 has an inside diameter smaller than the outside diameter of insert 9203 at sections 9219 and 9220. Fig. 9/2a shows the normally closed valve type A at its closed position. At this stage the pressure of the fluid at inlet 9204 and at cylinder 9210 is lower than the preset pressure P.O of the valve, elastic tube 9201 surrounds tightly section 9219 of insert 9203, sealing perforations 9212 and preventing the fluid from flowing from inlet 9204 through the valve to outlet 9205.

Fig. 9/2b shows the normally closed pulsating valve type A at its pulsating stage.

When the pressure P.l of the fluid at inlet 9204 increases and becomes higher than the preset pressure P.O of the valve, the pressure P.l of the fluid forces elastic tube 9201 to expand and its inside diameter to increase to D.l in respond to the pressure P.l. Fluid at a low controlled flow Q.O than flows from cylinder 9210 through perforations 9212 to space 9221 created between the inside diameter D.l of elastic tube 9201 and outside diameter of insert 9203 at section 9219. The fluid then flows at a low flow Q.O through the small open cross section created around section 9219 and a pressure drop dP is created along section 9219. In order that the fluid will continue to flow, the pressure at cylinder 9210 has to increase to P.2 and P.2 = P.l+dP In response to pressure P.2 the elastic tube 9201 inside diameter is increasing to D.2. At this stage a volume dV of fluid is accumulating between the elastic tube 9201 inside diameter D.2 and the insert outside diameter at section 9219. The larger open cross section created between the insert 9203 at section 9219 and the elastic tube 9201 inside diameter D.2 allows the volume dV of the fluid to flow at a high rate Q.l from space 9221 through sections 9219 and 9220 out through the valve outlet 9205 created around insert 9203 when elastic tube 9201 expands. The fluid then flows through port 9206 in casing 9202 to the deflector 9213 which controls the pattern of the ejected fluid. Since the fluid flows out from space 9221 at a high rate Q.l and flows into space 9221 at a low controlled rate Q.O, the volume of fluid dV in space 9221 decreases, the pressure of the fluid inside space 9221 decreases, the elastic tube 9201 inside diameter decreases and becomes smaller than the outside diameter of insert 9203 at section 9219, the elastic tube 9201 surrounds tightly perforations 9212 preventing the fluid from flowing out from cylinder 9210, closing the "valve" and terminating one pulsating cycle. Fig. 9/3 illustrates a "normally open pulsating valve" type B consisting of elastic tube 9301, casing 9302, inlet fitting 9303, and outlet fitting 9304. Inlet fitting 9303 has a fluid inlet 9305 and a port 9306 through which space 9307 surrounding elastic tube 9301 is pressurized. Outside diameter of inlet fitting 9303 at section 9308 is formed as a barb. Sections 9309 and step 9310 of the inlet fitting 9303 are formed for connecting casing 9302 to inlet fitting 9303. Outlet fitting 9304 has a fluid outlet 9311 and a barb 9312. Barbs 9308 and 9312 are made for holding elastic tube 9301 at a fixed place.

At the normally open position of the pulsating valve, fluid with a controlled low flow Q.O and a pressure P.l enters fluid inlet 9305 and then flows through the elastic tube 9301.

The fluid also enters through port 9306 to space 9307 pressurizing space 9307 with the same pressure P.l of the fluid at inlet 9305. As a result of friction loss in the elastic tube 9301 a pressure drop dP is created along the elastic tube 9301 and the pressure P.l inside elastic tube 9301 at its inlet 9313 drops to P.2 at section 9314 of the elastic tube 9301. The pressure surrounding the elastic tube 9301 is P.l which is higher than the pressure P.2 inside the elastic tube 9301 at section 9314 and as a result, elastic tube 9301 at section 9314 becomes flat, closing the valve. Since at this stage the fluid does not flow, and no pressure drop dP exists, the pressure at section 9314 increases to P.l, the elastic tube 9301 expands, the valve opens, and a volume dV of fluid ejects from elastic tube 9301 through fluid outlet 9311 at a high flow Q.2, terminating one pulsating cycle.

When the pressure at the fluid inlet 9305 is increased and becomes then a preset pressure P.C the elastic tube 9301 becomes flat and the valve will stay closed. The normally open pulsating valve can be produces also with a center rod supported by ribs where inlet fitting, outlet fitting, center rod, the ribs and the barbs are producedas oneunit, an insert. Fig. 10 illustrates a self cleaning filter having a pulsating valve structure.

The construction of this valve is the same as pulsating valve type A described in Fig. 9/1 in which part of the elastic tube section is perforated creating a "screen".

The valve consists of elastic tube 10101, casing 10102, and insert 10103. Insert 10103 has a fluid inlet 10104 and a fluid outlet 10105. Casing 10102 has a port 10106 through which space 10107 surrounding elastic tube 10101 can be vented. Port 10106 is also the filtered fluid outlet. Insert 10103 has a barb 10108 for holding elastic tube 10101 in a fixed position. Insert 10103 has a hole 10109 by which the valve can be supported on a rod. Fluid inlet 10104 has a hole in the form of a cylinder 10110 plugged at its end 10111 and having perforations 10112 at its circumference. Fluid outlet 10105 has an opening in the form of a cylinder 10113 plugged at its end 10114 and having perforations 10115 at its circumference. Section 10116 of insert 10103 and step 10117 are formed for connecting casing 10102 to insert 10103. Outside diameter of insert 10103 at section 10118 can be used for connecting the valve with its outside diameter at the fluid inlet to a fluid supply pipe or fitting. Fluid inlet 10104 has also an opening in the form of a casing 10119 for a flow control type B and as an option the flow through the valve can be controlled by elastic tube 10120. Center section 10121 of insert 10103 has an outside diameter smaller than section 10108. Section 10122 has a larger diameter than section 10121 and smaller than section 10108. Section 10123 has an outside diameter smaller than that of section 10121 and section 10124 has an outside diameter larger than section 10123. Outside or inside diameters of section 10125 can be used for connecting a deflector to the valve. Elastic tube 10101 surrounding insert 10103 at part of section 10121, between perforations 10112 and section 10122 is perforated forming a "screen".

Elastic tube 10101 inside diameter is smaller than the outside diameter of the insert at sections 10121 and 10123 and it surrounds tightly the insert 10103.

Fig. 10a shows the filter valve at its closed position. When the pressure of the fluid at cylinder 10110 is lower than the preset pressure P.O of the valve, elastic tube 10101 surrounds tightly section 10121 and perforations 10112 preventing from the fluid to flow out from cylinder 10110 through perforations 10112 and the valve stays close. Fig. 10b shows the filter valve at its filtering stage.

When the pressure P.l at cylinder 10110 is higher than a preset pressure P.O the fluid pressure forces elastic tube 10101 to expand and its inside diameter at section 10121 increases to D.l larger than the outside diameter of insert 10103. The fluid then flows from space 10126 through the perforations of the "screen" to space 10107 and out through port 10106. When perforations of elastic tube 10101 at its "screen" portion gets plugged up, the filter valve is converted to a pulsating valve, the pressure inside space 10126 increases, the elastic tube inside diameter becomes larger than the outside diameter of insert 10103 at section 10122, and fluid then ejects at a high pulsating flow from space 10126 through the open cross section created between the elastic tube 10101 inside diameter and the outside diameter of the insert 10103 at sections 10121, 10122 and 10123, through perforations 10115 and cylinder 10113 out through the fluid outlet 10105, flushing the "screen" allowing for the fluid to flow again through the "screen".

Fig. 11 illustrates different types of pumps having a pulsating valve structure and different applications of these pumps. Fig. 11/1 illustrates a fluid injection pump. The injection pump has a similar construction to that of a pulsating valve type A shown in Fig. 9/1 with the port in the casing locating opposite the perforations at the valve fluid inlet.

The injection pump consists of elastic tube 11101, casing 11102 and insert 11103. Insert 11103 has a fluid inlet 11104 and fluid outlet 11105. Casing 11102 has a port 11106 through which a fluid surrounding the pump can enter into space 11107 surrounding elastic tube 11101. Section 11108 of insert 11103 has a large outside diameter in the form of a barb for holding elastic tube 11101 in a fixed position. Insert 11103 has an opening 11109 by which the pump can be supported on a rod. Fluid inlet 11104 has an opening in the form of a cylinder 11110 plugged at its end 11111 and perforations 11112 at its circumference.

Fluid outlet 11105 has an opening in the shape of a cylinder 11113 plugged at its end 11114 and having perforations 11115 at its circumference. Section 11116 of insert 11103 and step 11117 are made for connecting casing 11102 to insert 11103. Outside diameter of section 11118 can be used as an option for connecting a fluid supply pipe or fitting to the pump. Fluid inlet 11104 has an opening in the form of a casing 11119 for flow control type B by which an elastic tube 11120 can be used for controlling the flow into the pump. Center section 11121 of insert 11103 has an outside diameter smaller than its diameter at section 11108 and larger than its diameter at section 11122. Inside and outside diameters of the insert 11103 at section 11123 can be used for connecting a pipe or a fitting for delivering the discharged fluid from the pump.

Fig. 11/la shows an injection pump at the stage in which the "pulsating valve" is close and a fluid M which surrounds the pump enters its casing 11102 through port 11106 filling space 11107.

Fig. 11/lb shows the stage at which fluid N enters the pump at a flow Q.l from its fluid inlet 11104 causing elastic tube 11101 to expand, pressing elastic tube 11101 against casing 11102 sealing port 11106 and increasing the pressure of the fluid M in space 11107. Fluid M then flows through the open space 11124 created between section 11122 of the insert 11103 and the elastic 11101 tube which is forced to expand and increase its inside diameter in response to the pressure of fluid N that flows through the pump in pulses. Fluid M than enters cylinder 11113 mixing and ejecting with fluid N and the mixture than flows through the pump outlet 11105 at a flow Q.3 and Q.3 = Q.l + Q.2.

Fig. 11/2 illustrates a "fluid driven pump" consisting of a pulsating device type A in which its casing has one port through which fluid M enters the pump, when the pulsating valve, is at its closed position and a second port through which fluid M is discharged from the pump at a higher pressure, when a fluid N flows through the pulsating valve forcing it to pulsate.

The pump consists of elastic tube 11201, casing 11202 and insert 11203. Insert 11203 has a fluid N inlet 11204 and a fluid N outlet. Casing 11202 has a port 11206 through which fluid M surrounding the pump can enter space 11207 surrounding elastic tube 11201. Casing 11202 has a second port 11208 trough which fluid M can be ejected from space 11207. Insert 11203 has a hole 11209 by which the pump can be supported on a rod. Fluid N inlet 11204 has an opening formed in the shape of a cylinder 11210 plugged at its end 11211 and having perforations 11212 at its circumference. Fluid N outlet 11205 has an opening in the form of a cylinder 11213 plugged at its end 11214 and having perforations 11215 at its circumference. Section 11216 of insert 11203 and step 11217 are made for connecting casing 11202 to insert 11203.

Section 11218 of insert 11203 can be used for connecting the pump by its outside diameter to a fluid N pipe supply or fitting.

Fluid N inlet 11204 has also a hole 11219 in the form of a casing for a flow control type B and the flow Q.l of fluid N into the pump can be controlled by an elastic tube 11220.

Section 11221 of insert 11203 has a large outside diameter in the form of a barb for holding the elastic tube 11201 at a fixed place. Center section 11222 has an outside diameter smaller than of section 11221. Section 11223 has an outside diameter smaller than that of section 11222, and section 11224 has an outside diameter larger than that of section 11223.

Outside and inside diameters of sections 11225 can be used for connecting a discharging pipe to fluid N outlet 11205.

Fig. ll/2a shows the pump at the stage in which the "pulsating valve" is at its closed position and fluid M flows through port 11206 into space 11207 filling it up.

Fig. ll/2b shows the pump at the stage in which fluid N enters the pump through the valve fluid N inlet 11204, causing it to pulsate. Elastic tube 11201 expands pressing against casing 11202, sealing port 11206, pressurizing the fluid in space 11207 and forcing it to eject through port 11208 at a flow Q.2 while fluid N is ejected through the valve fluid N outlet at a pulsating flow.

Fig. 11/3 illustrates the arrangement of an injection pump 11/1 pumping water from a reservoir M at a flow Q.2 mixing it and ejecting it with water N that enters the pump at a flow Q.l from source N, and the mixture flows out at a total flow Q.3 = Q.l + Q.2.

The system consists of an injection pump 11/1 connected to water supply pipe 11302, valve 1,1302 connected to outlet of injection pump 11/1, and a pipe 11303 connected to outlet of valve 11302. Water M in the reservoir is at elevation 11304 and it flows by gravity at a rate of Q.2 into the pump through its port 11106.

Water N enters the pump at a flow Q.l and flows out from it at a flow Q.3 = Q.l + Q.2.

Fig. 11/4 illustrates A pump 11/2 that is pumping water from a reservoir M when water from source N flows through the pump.

The installation consists of a pump 11/2, check valve 11401 connected to fluid N outlet of the pump. Fluid N water supply pipe 11402 fluid N discharging pipe 11403. Check valve 11404 connected to port 11208 of pump 11/2 [shown in Fig. 11/2 ] and fluid M discharging pipe 11405 connected to the outlet of check valve 11404. Water in reservoir M is at elevation 11406 and it flows by gravity at a rate of Q.2 into port 11206 of pump 11/2 filling space 11207 [see Fig. 11/2 ] of the pump when the "pulsating valve" is at its closed position. Fluid N that flows from pipe 11402 through pump 11/2 valve 11401 and fluid N discharge pipe 11403 causing the valve to pulsate and fluid M to eject at elevated pressure from space 11207 of pump 11/2 through its port 11208, check valve 11404 to M discharging pipe 11405. By operating pump 11/2 as described when fluid N flows through the pump at a flow Q.l water M is pumped and eject at a flow Q.2 at elevated pressure from reservoir M.

Fig. 11/5 illustrates a soaping device consisting of a "fluid driven pump" 11/2 with a liquid soap container 11501 connected to port 11208 of the pump. [please see also Fig. 11/2.]. The device is connected to a faucet which supplies water N to the fluid N inlet to the valve. Container 11501 is filled up with liquid soap.

Fig. ll/5a shows the valve at its closed position. Liquid soap from container 11501 flows through port 11206 of pump 11/2 into space 11207 of pump 11/2.

Fig. ll/5b shows the device at its soaping position. Water N flows through the pump 11/2 causing the "pulsating valve" to pulsate. Air enters port 11206 of pump 11/2 and flows out through the liquid soap at space 11207 of the pump and through port 11208 into container 11501 through the liquid soap 11502 in container 11501 converting the liquid soap to foam which flows by gravity to the pump 11/2 outlet 11205 where it is mixed and ejected with the water that flows at a high pulsating flow.

The pumps described in these figures have the same construction as pulsating valves type A as described is Fig. 9 with the port in the casing located opposite of the perforations at the inlet to the "receptacle container" of the pulsating valve. The perforations at the inlet to the "receptacle container" are located at one of its ends and the fluid flows out from the container at its other end.

At the closed position of the pulsating valve, the volume of fluid in the "receptacle container" is zero and the elastic tube surrounds tightly the insert. At this stage a fluid M which surrounds the valve, enters the casing of the valve through its port. When a fluid N enters the pulsating valve inlet, the elastic tube expands, pressing against the port at the casing, sealing it and compressing fluid M against the casing wall.

11/1 Injection pump is a pump as described in which fluid M enters the casing of the pump at a flow Q.l and fluid N enters the pump at a flow Q.2 and the two fluids are mixed and ejected through the pump outlet as a mixture with a flow Q.3 = Q.l + Q.2.

11/2 Fluid driven pump in this pump as described, in which fluid M enters the casing of the pump at one port is pressurized and flows out from the pump through a second port in the casing, when fluid N enters the pump inlet, it causes it to pulsate and become ejected through the pump outlet.

- When fluid N is water and fluid M ia air, the pump is a "Water Driven Compressor".

- When fluid N is air and fluid M is water, the device is an "Air Driven Pump".

11/3 Pumping water from a reservoir by means of injection pump. When the injection pump 11/2 is installed in a reservoir M, water N at a flow Q.l enters the pump inlet while M enters the pump through the casing port at a flow Q.2, a total flow Q.3 = Q.l + Q.2 flows out from the pump.

11/4 Pumping water from a reservoir by air driven fluid pump.

When pump 11/2 is installed in a reservoir with water M. When water N flows through the pump and causing it to pulsate, water M enters the pump through one port in its casing and flows out at a higher pressure from a second port at the casing. ll/5a soaping device functions as a "water driven compressor" with a liquid soap container connected to the air outlet at the casing of the pump. The device is connected to a faucet and when water flows through the liquid soap, it converts it to foam which flows by gravity to the pump outlet where it is mixed and eject with the water that flows out from the pump at high pulsating flow.

Fig. 12 illustrates pulsating low flow: spray heads, minisprinklers, rotating sprinklers and driplines for irrigation, connected to a lateral by means a pulsating valve.

Fig. 12/1 shows a pulsating spray head such as shown in Fig.9/1 or Fig. 9/2 connected by means of a rigid riser 12101 and Tee 12102 to a rigid pipe 12103.

A low flow Q.2 of water flows from pipe 12103 through riser

12101 through a flow control installed inside the pulsating valve

9/1 at which the low continuous flow Q.2 is converted to a high pulsating flow Q.l which ejects through a deflector to can be connected at the outlet from pulsating valve 9/1 or is formed at the outlet of pulsating valve 9/2. The high ejected flow Q.l that flows through the deflector is sprayed to a large designated area.

Fig. 12/2 shows a pulsating spray head such as shown in Fig.9/1 or Fig. 9/2 installed with its outlet below its inlet and connected by means of a riser 12201 and a Tee 12202 to pipe 12203.Such an arrangement can be used for example in green houses.

Fig. 12/3 shows a pulsating spray head such as shown in Fig. 9/1 or Fig. 9/2 connected to a flexible tube 12301 by means of flexible tube 12302. Pulsating spray head 9/2 is supported with a rod 12303 which is inserted into the ground 12304.

Fig. 12/4 shows pulsating spray heads such as shown in Fig.9/1 or Fig. 9/2 connected to the outlets of rotating sprinkler 12401.

The pulsating valve can be also installed at the inlet to the sprinkler head.

Fig. 12/5 Shows a pulsating drip tube in which irrigation tube 12501 supplies irrigation water through a pressure compensated dripper 12502 which supplies a low controlled flow Q.2 to a pulsating valve 12503 at which the low flow Q.2 that enters the pulsating valve from the dripper 12502 is converted to a high pulsating flow Q.l that flows through the fitting 12504 to tube 12505 and out through perforations 12506. The high pulsating flow Q.2 that flows through the perforations 12506 allow the size of perforation 12506 to be very large yet the amount of water that flows through each perforation 12506 is very small and equal to the amount of water that flows through dripper 12502 divided by the number of perforations in the tube 12505.

Fig. 13 illustrates a plant frost control system consisting of a screen 13101 surrounding a plant 13102 and a pulsating sprinkler 13103 connected with riser 13104 a to water supply pipe 13105. Screen 13101 is floating and supported by plant 13102 and hold at a fixed place by a pile of dirt 13106. By operating pulsating sprinkler 13103 a layer of water 13107 is held by the screen 13101 which at low temperature of 32 degrees F. is converted to ice forming an "Igloo" which isolates a volume of air 13108 which surrounds the plant 13102.

The theory by which this system operates is exactly the same theory by which the Eskimo igloo operates. The invention describes a method for building an igloo which surrounds the item that need to be protected from frost. The frost protection system according to this method consists of 2 basic elements:

- A "Sheath" for covering the item that needs frost protection.

- A pulsating spray head for wetting the "sheath" by using small application rates of water.

When the temperature drops to 32 degrees F. the water held on the "sheath" is converted to ice creating an igloo which confines a limited volume surrounding the item that needs protection. The "Sheath" should be made and installed according to the following specification:

Materials and shape of the sheath:

The sheath can be made of any material that can be wetted. Water can be held by the sheath in different ways:

- By absorption, such can for example be even paper.

- By surface tension, such can be for example a screen made of certain materials and having certain perforations size and shape. To assure good protection . the "igloo" should be completely sealed. An opening in the "igloo" will allow wind to flow through and the warm air inside the "igloo" will be replaced by cold air from outside. For this purpose the sheath has to be installed in such a way that it will be completely wet by the sprayer.

Plants have some specific requirements: Plants need light and they cannot be covered for a long period of time by a material that blocks the light.

- The space surrounding the plants has to be vented. - The plants require different treatments like chemical spraying, fertilizing, irrigation, etc..

In a large grove, covering the trees a short time before frost is expected and uncovering the trees a short time after the frost passes, is practically impossible. And for this purpose a screen can be used. By using a screen the space surrounding the plant is vented and has light and at the end of the frost the ice on the screen melts. The light can immediately penetrate through the screen and so does fresh air. By using screens the plants can be covered and removed a substantial long time before frost is expected and long time after the frost forecasting time.

Different types of screens can be used made of different materials. The screens can be durable, disposable or degradable and of a suitable degree of porosity or opening size.

For some applications floating screens can be used. Such screens are supported by the plants themselves. Other supporting means can be used too if needed.

The pulsating sprayer in order to wet the screen any type of sprinkler can be used yet a sprinkler with a high rate of water application will create a heavy layer of ice which will cause the screen to collapse. Sprinklers can apply small quantities of water when controlled by a timer. During frost if the sprinklers do not operate, the water freezes in the sprinklers' risers and nozzles and as a result operating high flow sprinklers in cycles is not a practical solution. In a large range, in order to protect all the plants, all the screens covering all the plants should be wetted at the same time, all the time. Most irrigation systems cannot operate this way because of their high flow. Most sprinklers systems operate in cycles. At the end of each irrigation cycle the water from the pipes, or from some of them, drains through the sprinklers nozzles and a certain time is wasted during the time in which the pipes are filled up again.

The pulsating sprinklers provide a solution for those problems. They can apply a low application of water to each screen, all the pulsating sprinklers can be operated at the same time and controlled by one valve, the pipes do not drain and no time is wasted for filling back the pipes. Such a system can be connected to a temperature sensor which automatically operates the system at a preset temperature.

The pulsating sprinklers can be installed inside or outside the "igloo" providing they fully wet the screens. A pulsating sprinkler installed inside the "igloo" has a few advantages: - As long as the pulsating sprinkler is operating water and energy is added to the isolated volume, elevating its temperature.

- The same pulsating sprinkler can ,be used for irrigation at regular times.

- Since the pulsating sprinkler itself is protected by the "igloo", water won't freeze in the sprinklers and they can be operated in cycles if needed.

Fig. 14 illustrates a self cleaning low flow pulsating pop up sprinkler consisting of casing 14101, casing's fluid inlet fitting 14102, casing's outlet fitting 14103, sliding guide 14104 riser 14105, "0 ring" 14106, pulsating low flow sprayer 14107 and sleeve 14108. Sliding guide 14104 is a filter in the form of a cylinder with the riser 14105 fits tightly its open end 14109. Casing outlet fitting 14103 has an inside diameter 14110 larger than the outside diameter of riser 14105 and a space 14111 is created at the outlet fitting between its inside diameter 14110 and outside diameter of riser 14105. The outside diameter of sliding guide 14104 and of "O ring" 14106 is smaller than the inside diameter of casing 14101.

Fig. 14a shows the pop up pulsating sprayer at its low position. At this position the pressure at casing inlet 14112 is low and no water flows into the pop up casing 14101. Fig. 14b shows the pop up sprayer at its rising stage. At this stage the irrigation valve which controls the flow to the lateral is turned on and pressurized water flows through casing inlet 14112 into casing 14101.

Water at this position flows to space 14115 between the fluid inlet 14112 and the sliding guide 14104 and than around the screen at space 14113 flushing the screen. The flushing water than flows out through space 14113, space 14114 and space 14111 out from the casing outlet which at this stage is open.

The pressure in space 14115 at this stage is lower than the preset pressure P.O of the pulsating spray head 14107 and no water flows through the normally closed pulsating spray head 14107. Fluid enters casing inlet 14112 at a flow Q.l and flows to space 14115. Some of the fluid flows at a rate of Q.2 out from casing 14101 through space 14113, space 14114 and space 14111. The rest of the fluid having a flow Q.3 = Q.l - Q.2 is used for increasing volume of space 14115, forcing the sliding guide 14106, the "0 ring" 14104, the riser 14105 and the sprayer 14107 to move up to its highest elevation.

Fig. 14/c shows the pulsating pop-up sprayer at its open position. At this stage sliding guide 14104 is pressing "0 ring" 14106 against the bottom of outlet fitting 14103, sealing space 14111. The pressure in space 14115 increases to P.2 higher than the preset pressure P.O of the pulsating sprayer and fluid flows through filter 14104 to riser 14105 and to pulsating sprayer 14107 at a low flow Q.O wetting a large designated area.

At any new irrigation cycle, fluid at a flow Q.2 flows through space 14113 flushing the filter 14104 and ejecting the flushing fluid through the open space 14111. - Since the pulsating sprinkler is normally closed, during the lifting stage of the sprinkler, no water flows through the sprinkler.

- The sprinkler operates at a low flow Q.O which is controlled by the flow control or by pressure compensated dripper at the inlet to the pulsating valve. As a result, the flow that enters the casing of the pop-up at the lifting stage and the operating flows are low. And when the ρoρ—up sprinklers operate, each sprinkler can have the same flow regardless of the pressure in the irrigation system..

- Since the required flows at the lifting and operating stages are low, a small size pop-up casing and riser can be used.

- Lifting height of the pop-up sprayer is theoretically unlimited.

- Sliding guide of this pop-up can be is a screen which filters the water that flows through the flow control and the pulsating sprayer. The screen is being flushed at each new irrigation cycle.

Fig. 15 illustrates by diagram and structure a method and devices for controlling different outlets connected to the same pipe and operate separately by changing the pressure in the pipe.

Fig. 15/1 shows a "limiting valve" consisting of a normally closed valve which opens itself at a preset pressure P.O connected to the outlet of a normally open valve which closes itself at a preset pressure P.C. higher than P.O

Fluid can flow through such a "limiting valve" from its fluid inlet 15101 to its fluid outlet 15102 only when its pressure at the fluid inlet 15101 is at a range of P.O. to P.C. At any pressure lower than P.O. at the fluid inlet 15101 to the "limiting valve". The normally closed valve eliminates the fluid from flowing through the valve. At any pressure higher than P.C. at the fluid inlet 15101 to the "limiting valve" the normally open valve eliminates the fluid from flowing through the valve. Fig. 15/2 is a schematic drawing showing an example of a system consisting of 6 groups of outlets connected to the same pipe and operating separately by changing the pressure in the pipe. Group 15201 consists of a normally open valve with a preset closing pressure P.C. = 20 psi is connected to outlet 15202 from pipe 15203.

Group 15204 consists of "limiting valve" 15/1 with pressure opening range of 25 to 30 psi and connected to outlet 15207 from pipe 15203.

Group 15208 consists of "limiting valve" 15/1 with pressure opening range of 30 to 35 psi connected to outlet 15209 from pipe 15203. Group 15210 consists of "limiting valve" 15/1 with opening range of 25 to 40 psi connected to outlet 15211 from pipe 15203.

Group 15212 consists of normally closed valve with a preset opening pressure of 40 psi connected to outlet 15213 from pipe 15203. The pressure in pipe 15203 is controlled by valve 15214.

- At any pressure lower than 20 psi at pipe 15203 fluid flows out from pipe 15203 only through outlet 15202 and group 15201. - At any pressure ranging from 20 to 25 psi at pipe 15203 fluid flows only through outlet 15205 and group 15204.

- At any pressure ranging from 25 to 30 psi at pipe 15203 fluid flows out from pipe 15203 only through outlet 15207 and group 15206. - At any pressure range of 30 to 35 psi at pipe 15203 fluid flows out from pipe 15203 only through outlet 15209 and group 15208.

- At any pressure ranging from 35 to 40 psi at pipe 15203 fluid flow out from pipe 15203 only through outlet 15211 and group 15210.

- At any pressure higher than 40 psi at pipe 15203 fluid flows out from pipe 15203 only through outlet 15213 and group 15212. Fig. 16 illustrates two types of normally open hydraulic valves.

Fig. 16/1 illustrates a normally open hydraulic valve type A consisting of elastic tube 1101, casing 1102, inlet fitting 1103 and outlet fitting 1104. Inlet fitting 1103 has a fluid inlet 1105 and outlet fitting 1104 has a fluid outlet 1106. Casing 1102 has a port 1107 through which space 1108 surrounding the elastic tube 110l can be pressurized, for closing the valve, or vented for opening the valve. Inlet fitting 1103 has a barb 1109 and outlet fitting 1104 has a barb 1110. Barbs 1109 and 1110 are made for holding the elastic tube 1101 at a fixed position.

Fig. 16/la shows the hydraulic valve at its normally open position when space 1108 is vented. Fluid at this position of the valve can flow from fluid inlet 1105 through elastic tube 1101 out through fluid outlet 1106.

Fig. 16/lb shows the valve at its close position when space 1108 is pressurized. Elastic tube 1101 becomes flat with its walls pressed against each other, closing the valve and eliminating from a fluid to flow from the fluid inlet 1105 to the fluid outlet 1106.

As shown in the figure, the valve comprises an elastic tube installed inside a rigid casing having fluid inlet, fluid outlet and a port through which the space surrounding the elastic tube is pressurized for closing the valve and vented for opening the valve. At the normally open position of the valve fluid flows through the elastic tube and out through the valve's outlet.

When the space surrounding the elastic tube is pressurized the elastic tube becomes flat, its walls become pressed against each other, closing the valve.

Fig. 16/2 illustrates a normally open hydraulic valve type B which has the same shape as the normally open hydraulic valve type A in which inlet fitting and outlet fitting are connected by means of a center rod.

This valve consists of elastic tube 1201, casing 1202 and insert 1203. Insert 1203 has a fluid inlet 1204 and fluid outlet 1205.

Casing 1202 has a port 1206 through which space 1207 surrounding elastic tube 1201 is pressurized for closing the valve and vented for opening the valve. Insert 1203 has a large outside diameters formed as barbs 1208 and 1209 by which elastic tube 1201 is held at a fixed place. Insert 1203 has a center rod 1210 and supporting ribs 1211 at the inlet 1204 and 1212 at the outlet 1205. This allows inlet fitting 1204, outlet fitting 1205, center rod 1210, supporting ribs 1211 and 1212 and barbs 1208 and 1209 to be produced as one part, insert 1203.

Elastic tube 1201 inside diameter is larger than the outside diameter of center rod 1210.

Fig. 16/2a shows normally open hydraulic valve type B at its normally open position. At this position of the valve a fluid can flow from fluid inlet 1204, bypassing ribs 121l^", through space 1213, surrounding center rod 1210, bypassing ribs 1212, and out through fluid outlet 1205. Fig. 16/2b shows the normally open hydraulic valve type B at its closed position. At this stage space 1207 is pressurized, elastic tube 1201 is pressed against center rod 1210 surrounding tightly the rod 1210 and eliminating the fluid from flowing from the fluid inlet 1204 to the fluid outlet 1205, closing the valve. The normally open hydraulic valve may include also a center rod as shown with an outside diameter smaller than the inside diameter of the elastic tube. The center rod is supported between the inlet and the outlet by means of ribs or the like. At the normally open position of the valve, fluid flows from the inlet, bypassing the ribs, through the space created between the elastic tube and the rod, bypassing the ribs at the outlet and out through the fluid outlet. At its close position the elastic tube surrounds tightly the center rod.

Fig. 17 illustrates a normally closed hydraulic valve consisting of elastic tube 2101, casing 2102 and insert 2103. Insert 2103 has a fluid inlet 2104 and a fluid outlet 2105. Casing 2102 has a port 2106 through which space 2107 surrounding elastic tube 2101 can be pressurized or vented. Insert 2103 has large outside diameter in the form of barbs 2108 and 2109 for holding the elastic tube 2101 at a fixed place. Insert 2103 has a center rod 2110, supporting ribs 2111 at inlet 2104 and ribs 2112 at outlet 2105. Section 2113 of rod 2110 has a diameter larger than the inside diameter of elastic tube.

The term "barbs" as used herein and elsewhere in the specification and claims refers to transverse projections on the insert which serve to define the diameter of the insert and retain the tubular elastic member. In most cases the tube ends will be held in position by the elastic tension but where necessary cementing may also be used at such points. Fig 17a shows the normally closed hydraulic valve at its normally closed position. At this position elastic tube 2101 surrounds tightly rod 2110 at its large diameter portion 2113, eliminating from a fluid to flow from the valve fluid inlet 2104 to the fluid outlet 2105. Fig.17b shows the normally close hydraulic valve at its open position. At this position the pressure of the fluid at the fluid inlet 2104 is higher than the preset pressure P.O of the valve, and the pressure of the fluid is forcing the elastic tube 2101 to expand, its inside diameter increases and becomes larger than the outside diameter of the center rod 2110 at section 2113, allowing the fluid to flow from inlet 2104, bypassing ribs 2111 through the elastic tube 2101 and the space 2114 created around the rod 2110 at its large section 2113, bypassing ribs 2112 and out through outlet 2105. At this stage the valve can be closed by pressurizing space 2107 or by decreasing the pressure at the fluid inlet 2104 bellow the preset pressure P.O of the valve. This valve has the same construction as that of a normally open hydraulic valve with the elastic tube surrounding a center rod. Part of the rod has a diameter larger than the inside diameter of the elastic tube. At its normally closed position the elastic tube surrounds tightly the large portion of the rod

This hydraulic valve will open itself when the port in the casing is vented and the pressure at the valve inlet is higher than a preset pressure P.O The valve will close itself when the pressure at the inlet is reduced to a pressure lower than P.O or when the space surrounding the elastic tube is pressurized through the port in the casing.

Fig.18 illustrates a normally closed valve consisting of elastic tube 3101, casing 3102, and insert 3103. Insert 3103 has a fluid inlet 3104 and a fluid outlet 3105 .

Casing 3102 has a port 3106 through which space 3107 surrounding the elastic tube is vented.

Insert 3103 has barbs 3108 and 3109 by which elastic tube 3101 is held its place. Fluid inlet 3104 has a hole in the form of a cylinder 3110 plugged at its end 3111 and has perforations 3112 at its circumference. Fluid outlet 3105 has a hole in the form of a cylinder 3113 plugged at its end 3114 and has perforations 3115 at its circumference. Insert 3103 has an outside section 3116 and a step 3117 by which casing 3102 is connected to insert 3103. At inlet 3104 insert 3103 has an outside diameter 3118 that can be used for connecting the pulsating valve at its outside diameter to a fluid supply pipe or a pipe fitting .

Outlet fitting 3105 has an outside diameter 3119 that can be used for connecting the pulsating valve at its outside diameter to a sprinkler or any other device.

Center section of insert 3103 has an outside diameter 3120 larger than inside diameter of elastic tube 3101 and elastic tube surrounds tightly the insert 3103.

Fig. 18a shows the normally close valve at its normally closed position. At this position elastic tube 3101 surrounds tightly the insert 3103, closing perforations 3112 and 3115, eliminating from fluid to flow from the fluid inlet 3104 to the fluid outlet 3105 keeping the valve in a closed position.

Fig. 18b shows the valve at its open position.

When the pressure of the fluid at the fluid inlet 3104 and at cylinder 3110 is increased and becomes higher than a preset pressure P.O of the valve, the pressure of the fluid forces the elastic tube 3101 to expand and its inside diameter to become larger than the outside diameter 3120 of insert 3103. The fluid than flows from fluid inlet 3104 through cylinder 3110 and perforations 3112 to space 3121 created between the insert 3103 and the elastic tube 3101, through perforations 3115 to cylinder 3113 and out through outlet 3105. The valve will stay at its open position as long as the pressure at the valve fluid inlet 3104 is higher than the preset pressure P.O of the valve.

This valve operates only in response to pressure changes at the inlet to the valve and for this purpose a normally closed hydraulic valve with its port in the casing vented can be used. Normally closed valves can also consists of two elements, an insert, and elastic tube surrounding tightly the insert.

Such a valve comprises an insert in which each of its ends has a cylindrically shaped hole perforated at its circumference and plugged at its end. Both ends are formed as barbs by means of which the elastic tube is held fixed. The center section of the insert has an outside diameter larger than the inside diameter of the elastic tube. When the pressure at the inlet [or the outlet] is lower than a preset pressure P.O the elastic tube surrounds tightly the center section of the insert and the perforation of the cylinders at the inlet and the outlet. When the pressure at the inlet is P.2 higher than P.O, the fluid flows from the cylinder at the inlet through the perforation in its circumference to a space created between the outside diameter of the insert and the elastic tube to the perforations of the cylinder at the outlet then through the cylinder and out from the valve outlet. The casing is used to protect and support the elastic tube assembly. Fig. 19 illustrates a normally open pressure responsive valve consisting of elastic tube 4101, casing 4102, and insert 4103. Insert 4103 comprise of fluid inlet 4104, fluid outlet 4105, port 4106 through which space 4107 surrounding elastic tube 4101 is pressurized, barbs 4108 and 4109 by which elastic tube 4101 is held at a fixed place, a center rod 4110 supported by ribs 4111 at inlet 4104 and ribs 4112 at outlet 4105. Insert 4103 has an outside diameter 4113 by which a fluid supply pipe or fitting 4114 can be connected to the valve. The Figure shows the valve at its normally open position in which a fluid can flow from the fluid inlet 4104, bypassing ribs 4111 through elastic tube 4101 around center rod 4110, bypassing ribs 4112 and out through fluid outlet 4105. In space 4107 the fluid has the same pressure as at the fluid inlet 4104. When the pressure at the fluid inlet is increased and becomes higher than a preset pressure P.C. the force created by the fluid at space 4107 pressing on elastic tube 4101 outside diameter becomes larger than the force acting on elastic tube 4101 on its inside diameter and as a result the elastic tube 4101 inside diameter decreases and the elastic tube 4101 surrounds tightly center rod 4110 eliminating from fluid to flow from inlet 4104 to outlet 4105 closing the valve. The valve will stay closed as long as the pressure of the fluid at inlet 4104 will be higher than a preset pressure P.C.

This valve has the same construction as that of a normally open hydraulic valve with its pressurizing port connected constantly to a pressure source at the valve inlet. The elastic tube is exposed to the same pressure inside and outside its circumference and since the outside diameter of the elastic tube is larger than its inside diameter the force F.3 on the elastic tube from outside is larger than the force F.2 on the pipe from inside.

The force deferential d F = F.3 - F.2 will cause the tube to become flat when it is larger than the resistance dF.O of the tube to become flat at a certain preset pressure P.C according to the conditions described in formula (5) . Fig. 20 illustrates a normally closed valve for spray heads consisting of elastic tube 5101, casing 5102 and insert 5103. Insert 5103 has a fluid inlet 5104 and fluid outlet 5105. Casing 5102 has a port 5106 through which space 5107 surrounding elastic tube 5101 is vented. Insert 5103 has a barb 5108 by which elastic tube 5101 is held at a fixed place. Insert 5103 has a hole 5109 by which the valve can be supported on a rod. Fluid inlet 5104 has a hole in the form of a cylinder 5110 plugged at its end 5111 and having perforations 5112 at its circumference. Insert 5103 has a hole 5113 by which a deflector 5114 is connected to the valve. Insert 5103 has a section 5115 and a step 5116 by which casing 5102 is connected to insert 5103. Insert 5103 has at its center section an outside diameter 5117 smaller than the inside diameter of elastic tube 5101. Fig. 20a shows the valve at its closed position. Elastic tube 5101 surrounds tightly outside diameter 5117 of insert 5103 and perforations 5112 preventing fluid flow from the fluid inlet 5104 and perforations 5112 to the fluid outlet 5105.

Fig. 20b shows the valve at its open position.

When the pressure of the fluid at the fluid inlet 5104 and in cylinder 5110 is increased and becomes higher than the preset pressure P.O of the valve. The pressure of the fluid forces the elastic tube 5101 to expand, its inside diameter becomes larger than the outside diameter 5117 of insert 5103 and the fluid than flows from the fluid inlet

5104 and cylinder 5110 through perforations 5112 and space

5118 created between the insert 5103 and the elastic tube 5101 through outlet 5105 and port 5106 to deflector 5114 which controls the pattern of the flowing fluid.

The fluid will continue to flow through the valve and the deflector 5114 as long as the pressure of the fluid at inlet 5104 will be higher than the preset pressure P.O of the valve.

As shown, the valve consists of an insert surrounded tightly by an elastic tube and having a cylindrical hole at one end which is the inlet of fluid to the valve. The cylinder is plugged at its end and has perforations at its circumference communicating with the elastic tube. Outside diameter of the insert at the inlet section is formed as a barb for holding the elastic tube at a fixed place. Outside diameter of the insert, at its end, is the fluid outlet, from which the fluid flows, when the valve opens and the elastic tube expands, through the space created between the elastic tube and the insert. The fluid flows to a deflector connected to the insert end, which controls the pattern of the ejected fluid. The elastic tu_be has an

c iMnsert. Wh^βen the^Ufl^Λuid pres^Wsure at the inlet's cylinder is lower than a preset pressure P.O the valve stay close. When the pressure at the cylinder is higher than the preset pressure P.O the valve opens. * The deflector is connecter to the valve without a bridge.

* The fluid does not flow from the valve to the deflector through a nozzle.

* When the valve is closed, its outlet is closed.

* Solid particles trapped at the valve outlet do not change the flow through the valve and cannot eliminate the valve from closing itself at a low pressure.

* Solid particles trapped at the valve outlet are causes the elastic tube to expand more, flushing them.

Fig. 21 illustrates a normally closed spray head with a deflector being an integral part of the insert. The drawing shows the valve at its normally closed position.

The valve consists of elastic tube 6101, casing 6102 and insert 6103. Insert 6103 has a fluid inlet 6104 and a fluid outlet 6105. Casing 6102 has a port 6106 through which space 6107 surrounding elastic tube 6101 is vented.

Insert 6103 has a barb 6108 by which elastic tube 6101 is held at a fixed place.

Insert 6103 has a hole 6109 by which the valve can be supported on a rod. Fluid inlet 6104 has a hole in the form of a cylinder 6110 plugged at its end 6111 and having perforations 6112 at its circumference.

Section 6113 and step 6114 of insert 6103 are formed for connecting casing 6102 to insert 6103. Top of insert 6103 is formed in a shape of a deflector 6115.

Center section of insert 6103 has an outside diameter 6116 larger than the inside diameter of the elastic tube 6101 and the elastic tube 6101 surrounds tightly the insert 6103.

The Figure shows the valve at its normally closed position.

Elastic tube 6101 surrounds tightly insert 6103 at its outside diameter 6116 sealing perforations 6112 and eliminating fluid flow from the fluid inlet 6104 to the fluid outlet 6105.

When the pressure at the fluid inlet 6104 and at cylinder

6110 is increased and becomes higher than the preset pressure P.O of the valve the pressure of the fluid forces the elastic tube 6101 to expand, its inside diameter becomes larger than the outside diameter 6116 of insert

6103 and the fluid then flows from the fluid inlet 6104 and cylinder 6110, through perforations 6112 out through a space created between the elastic tube 6101 and the insert

6103, through the fluid outlet 6105 and port 6106 to deflector 6115 which controls the pattern of the ejected fluid. The valve will stay open as long as the pressure at the fluid inlet 6104 is higher than the preset pressure P.O of the valve.

This normally closed spray head has the same construction as that of the valve described above, with the deflector being part of the valve itself. The deflector is created by different combinations of the insert and the elastic tube.

Fig.22 illustrates two types of flow controls.

Fig. 22/1 illustrates flow control type A which has a similar construction to that of a normally open valve. The valve consists of elastic tube 7101, casing 7102, inlet fitting 7103 and outlet fitting 7104. Inlet fitting 7103 has a fluid inlet 7105 and a port 7106 through which space 7107 surrounding elastic tube 7101 is constantly pressurized at the same pressure of the fluid at the fluid inlet 7105. Inlet fitting has a barb 7108. Inlet fitting has also section 7109 and step 7110 for connecting casing 7102 to inlet fitting 7103. Outlet fitting 7104 has a fluid outlet 7111 and a barb 7112. Barbs 7108 and 7112 are formed for holding elastic tube 7101 at a fixed place. Elastic tube 7101 has a length and inside diameter such that at a certain nominal flow Q.O a fluid can pass through the elastic tube 7101 without or with a negligible pressure drop along the tube. When the pressure P.3 at the fluid inlet 7105 increases a flow increase results in a pressure drop dP in the elastic tube 7101 and as a result of the pressure drop dP, the pressure inside the elastic tube 7101 drops from P.3 to P.2 where P.2 = P.3 - dP. The force on the outside diameter of elastic tube 7101 becomes larger than the force on the inside diameter of elastic tube 7101 and as a result inside diameter of elastic tube 7101 between cross section 7113 at the inlet to elastic tube 7101 and cross section 7114 at the outlet from elastic tube 7101, decreases, preventing the flow of the fluid through the valve from increasing. The range of pressures P.3 at which this valve operates as a flow control depends on the dimensions and physical properties of the elastic tube 7101 as well as the pressure drop dP created in the elastic tube 7101. When the pressure P.3 of the fluid at the fluid inlet 7105 increases and becomes higher than a preset pressure P.C. the flow control will close itself.

Fig. 22/1 shows the flow control at a position in which the pressure at the fluid inlet 7105 is lower than P.C. and the fluid is flowing through the valve at a controlled flow Q.O. Fig. 22/2 illustrates a flow control type B which operates at the same way flow control type A operates. Flow control type B consists of elastic tube 7201, casing 7202 and insert 7203. Insert 7203 has a fluid inlet 7204 and casing 7202 has a fluid outlet 7205. Casing 7202 has an inside diameter 7206 by which insert 7203 with its outside diameter 7207 is connected to the casing 7202. Casing 7202 has also a smaller inside diameter 7208 with slots 7209 at its inside circumference which at section 7210 are deeper than slots 7209. At section 7211 the casing 7202 has no slots and, casing 7202 has a hole in the form of a cylinder 7212 having an inside diameter smaller than in section 7211. Cylinder 7212 is plugged at its end 7213 and has perforations 7214 at its circumference which are also the fluid outlet 7205 of the flow control. Elastic tube 7201 at its outside diameter fits casing 7202 at its inside diameter 7211.

Fluid flows from the fluid inlet 7204 through, through elastic tube 7201 and out through the fluid outlet 7205 and at the same time the fluid fills slots 7209 and as a result the pressure P.3 of the fluid surrounding the elastic tube 7201 is the same pressure P.3 of the fluid at the fluid inlet 7204. When the fluid is flowing at a nominal flow Q.O, negligible pressure drop is created along elastic tube 7201. When pressure P.3 increases a pressure drop dP is created in the elastic tube 7201 and the pressure inside the elastic tube 7201 drops from P.3 at the inlet 7215 to the elastic tube 7201 to a pressure P.2 at the outlet 7216 from elastic tube 7201 and P.2 = P.3 - dP. The pressure inside elastic becomes lower than the pressure P.3 surrounding the elastic tube 7201 and as a result the elastic tube inside diameter decreases, eliminating from the nominal flow Q.O to increase thus controlling the flow through the valve. The flow controls described have the same construction as the construction of a normally open valve in which the elastic tube has such dimensions, length and inside diameter, that when the pressure P.3 at the inlet increases, fluid flow through the tube and a pressure drop dP is created in the elastic tube and as a result the pressure in the elastic tube drops from P.3. at the inlet to the tube to P.2. at any cross section along the tube. The space surrounding the elastic tube is connected to the fluid inlet and has the same pressure P.3 as the inlet to the elastic tube. Because of the pressure differential dP = P.3 - P.2 the inside diameter of the elastic tube decreases, restricting the flow from increasing, thus controlling it. The conditions at which this valve controls the flow are described in formula (4) .

Flow control type A has the same construction as a normally open valve and consists of a casing, inlet, outlet and elastic tube connected between the inlet and the outlet fittings. The inlet fitting has a hole through which the space surrounding the elastic tube is pressurized and has the same pressure P.3 as at the inlet to the elastic tube. The elastic tube has an inside diameter and a length such that when fluid flows through it at a flow higher than a certain "nominal flow' Q.O. friction lose or pressure drop dP causes the pressure to the elastic tube to decrease from P.3 at the inlet to P.2 at the outlet and as a result the pressure P.3 surrounding the elastic tube becomes larger than the pressure P.2 and the elastic tube is forced to decrease its inside diameter, restricting increase in flow. Flow control type B operates exactly like flow control type A although it has a different structure. Flow control type B consists of a casing having a cylindrical shaped inlet plugged at its end and having perforations at its circumference which are the outlet of the flow control. The cylinder has an inside diameter in which an elastic tube is installed.

The casing has a slot which creates an open space surrounding the elastic tube. A fluid that enters the valve's inlet enters the space surrounding the elastic tube pressurizing with the same pressure that the fluid has at the inlet to the elastic tube.

At a nominal flow, pressure drop along the elastic tube is minor, the pressure surrounding the elastic tube is the same as the pressure at the outlet from the elastic tube.

When the pressure at the inlet to the valve is increasing, the flow through the elastic tube tends to increase, but a flow increase through the elastic tube results in a pressure drop along the tube. The pressure in the space sui- rctimr- ϊ ncr h o as i r; -. nV-x- hι-rτιτnc.e; T amor f '^{a r}' the pressure inside the elastic tube and as a result the inside of the elastic tube decreases and this prevents the flow through the valve from increasing thus controlling it.

Since the flow is controlled by a tube and not by an orifice a tube with a relatively large open cross section can be used for controlling low flow of liquids.

Fig. 23 represents different types of receptacle containers.

Fig. 23/1 illustrates receptacle container type A. The container consists of elastic tube 8101 plugged at one end 8102 [or a balloon] and an insert 8103 which incorporates the inlet 8104 to the container which serves also as the outlet from the container. Insert 8103 has a barb 8105 by which elastic tube 8101 is held at fixed place. Insert 8103 has a hole in the form of a cylinder

8106 plugged at one end 8107 and having perforations 8108 at its circumference. Insert 8103 has at section 8109 an outside diameter smaller than the outside diameter of barb 8105. Elastic tube 8101 has an inside diameter smaller than the outside diameter of insert 8103 at section 8109 and the elastic tube 8101 surrounds tightly insert 8103 and perforations 8108 forming a normally closed valve.

Fig. 23/la shows the container at its empty position. Elastic tube 8101 is flat and at this stage the container has zero volume. A fluid can enter the container through the fluid inlet 8104 only if its pressure is higher than the preset pressure P.O of the valve.

Fig.23/lb shows the receptacle type A full with pressurized fluid.

In order that a fluid will enter the container it has to be injected through the fluid inlet 8104 at a pressure P.l higher than the preset pressure P.O of the normally closed valve created at the valve inlet/outlet 8104 by the elastic tube 8101 which surrounds tightly perforations 8108 at section 8109. A fluid at a pressure P.l higher than P.O forces the elastic tube 8101 to expand and the fluid then flows from inlet 8104 through perforations 8108 into space 8110 created when the elastic tube 8101 expands. When a volume dV enters space 8110 the volume of the container itself is increasing by dV. When the fluid ^' flows into space 8110 the pressure of the fluid in space 8110 increases from zero [atmospheric pressure] to P.2. At a pressure P.2 lower than P.O injection of the fluid stops. The fluid can flow out from space 8110 only when its pressure becomes higher than the preset pressure P.O. The pressure inside space 8110 can be increased by pressing on elastic tube 8101 and by doing it, the pressure inside space 8110 increases and become higher than P.O and the fluid than flows from space 8110 out through outlet 8104. When a volume dV of fluid flows out from the container the volume of the container itself decreases by dV. Fig. 23/2 illustrates receptacle type B. The container consists of elastic tube 8201, casing 8202 and insert 8203. Insert 8203 has a fluid inlet 8204 and a fluid outlet 8205. Casing 8202 has a port 8206 through which space 8207 surrounding the elastic tube is vented. 5 The outside diameter of insert 8203 at section 8208 and step 8209 are made for connecting casing 8202 to insert 8203. Fluid inlet 8204 has an opening in the form of a cylinder 8210 plugged at its end 8211 and having perforations 8212 at its circumference. Fluid outlet 8205 10 has a hole in the form of a cylinder 8213 plugged at its end 8214 and having perforations 8215 at its circumference. The outside diameter of insert 8203 at section 8216 is larger than at section 8217 and smaller than at section 8218. Center section 8219 of insert 8203 has an outside 15 diameter smaller than at section 8216 and smaller than its diameter at section 8220. At section 8221 the insert 8203 has an outside diameter larger than in section 8220. Elastic tube 8201 has an inside diameter smaller than the outside diameter of insert 8203 at its center section 8219 z σ cn_α _τs suωi cue t- α_> ι_-n-- LUJJC O Λ KJ J.. am J. uu.ι.n_> — -j.yu *--J-_ — JW-J. >- 8203 .

Fig. 23/2a shows the container at its empty position. At this stage a fluid can flow through the valve inlet,or outlet only if it is injected at a pressure which is higher 5 than the preset pressure P.0/1 of the valve at the inlet or

P.0/2 at the outlet.

Fig. 23/2b illustrates the receptacle container full with pressurized fluid.

In order to fill the container a fluid is injected 0 through inlet 8204 at a pressure P.l higher than the preset pressure P.0/1 of the normally closed valve created by the elastic tube 8201 which surrounds tightly the large outside diameter at section 8216 of insert 8203. The pressurized fluid then enters space 8222 created between the center section 8219 of insert 8203 and the elastic tube 8201 which expands in respond to the pressure of the fluid. At a certain pressure P.2 inside space 8222 the injection of the fluid into the receptacle container terminates. Pressure P.2 is lower than the preset pressure P.0/2 of the normally closed valve created at outlet 8205 by the elastic tube 8201 which surrounds tightly outside diameter 8220 of insert 8203. By pressing on the flexible casing 8202 the pressure inside space 8222 increases to P.3 which is higher than P.0/2 and lower than P.0/1 and the fluid flows from space 8222 out through outlet 8205. When a volume dV of fluid flows out from space 8222 the volume of the receptacle container decreases from V.O to V.l and the pressure inside space 8222 decreases from P.2 to P.4. When all the fluid stored at space 8222 is forced to flow out from the container the pressure in space 8222 drops to P.5 which means even the last drop in the container is under pressure. No fluid can enter space 8222 neither from inlet 8204 nor from outlet 8205 unless it is injected at a pressure higher than the preset pressures P.0/1 or P.0/2. The fluid can be ejected from space 8222 also by pressurizing space 8207 through port 8206 at casing 8202. By pressurizing space 8207 the pressure inside space 8222 increases to P.2 higher than the preset pressure P.0/2 and the fluid is forced to eject from space 8222 out through outlet 8205.

Fig. 23/3 illustrates receptacle type C which has a normally closed spring loaded valve at its outlet. [The normally closed spring loaded valve is not shown in the drawing]. The container consists of elastic tube 8301, casing 8302 and insert 8303. Insert 8303 has a fluid inlet 8304 and a fluid outlet 8305. Casing 8302 has a port 8306 through which space 8307 surrounding elastic tube 8301 is vented. Section 8308 and step 8309 are made in insert 8303 for connecting casing 8302 to insert 8303. Fluid inlet 8304 has an opening with a shape of a cylinder 8310 plugged at its end 8311 and having perforations 8312 at its circumference. At its outlet 830.5 insert 8303 has an opening in the form of a cylinder 8313 plugged at its end 8314 and having perforations 8315 at its circumference. Section 8316 of insert 8303 has an outside diameter larger than the outside diameter at section 8317 and smaller than at section 8318. Center section 8319 of insert 8303 has an outside diameter smaller than section 8316 and smaller than of section 8320. Elastic tube 8301 has an inside diameter smaller than the outside diameter of the center section 8319 of insert 8303 and as such the elastic tube 8301 surrounds tightly the insert 8303. Fig. 23/3a shows the container at its empty position. At this position a fluid can enter the container only if its pressure is higher than a preset pressure P.O of the normally closed valve created at the inlet 8304 to the container. Fig. 23/3b shows the receptacle full with pressurized fluid. When a fluid is injected to the container from inlet 8304 at a pressure P.l higher than the preset pressure P.0/1 of the normally closed valve created at section 8317 of insert 8303 the fluid enters space 8321 created between the outside diameter 8319 of insert 8303 and the elastic tube 8301 which is forced to expand in response to the pressure of the fluid. When the pressure of the fluid is P.2 lower than the preset pressure P.0/1 the injection of the fluid terminates. The pressure of the fluid at inlet 8304 drops to zero [atmospheric pressure] and _he normally closed valve at the inlet 8304 closes itself, at sections 8316 and 8317 preventing the fluid at space 8321 from flowing back through inlet 8304. Outlet 8305 is sealed with a normally closed spring loaded valve. By pressing on the spring loaded valve, outlet 8305 opens and the fluid flows out from space 8321 through outlet 8305 and the spring loaded valve. When a volume dV of fluid flows out from space 8321 the volume of the container decreases by dV. The pressure of the fluid at space 8321 is at a range of P.2 when the container is full to P.3 when it is empty "last drop". No fluid can enter space 8321 through inlet 8304 or outlet 8305 unless it is pressurized.

The pressure by which the fluid ejects from space 8321 can be increased by pressing on casing 8302 or by pressurizing space 8307 through port 8306.

Casing 8302 can be also rigid and without port 8306. In this case when a fluid is injected into space 8321 the air at space 8307 is compressed creating additional pressure on the fluid stores at space 8321.

As shown in the figures different types of receptacle containers are described which have "zero" volume when they are empty and when fluid is injected into the containers the volume of the container increases at the same volume V of the fluid that flows into the container and at the same time the pressure inside the container increases from P.l to P.2.

- No fluid can penetrate into the container unless its pressure is higher than a preset pressure P.O. - The fluid inside the container is pressurized and it flows out from the container only if its pressure increases to a pressure higher than a preset pressure P.O or by turning on a valve at its outlet.

- The fluid is stored in the container at a pressure P.3 when the container is full and a pressure P.2 when the container is empty [last drop of fluid] which are lower than a preset pressure P.O.

Three types of expandable containers are described as follow: Tvoe A. (23/la + 23/lb)

This container has a form of a "Balloon" having a fluid inlet at one end and plugged at its other end. Such a balloon can be produced at the same way balloons are produced or by using elastic tube plugged at the end. The fluid inlet to the container which is also the outlet of fluid from the container is formed at the same way a normally closed valve is produced. The inlet fitting consists of an insert which is surrounded tightly by the elastic tube which forms the container. The elastic tube can be a flat tube and as such it has zero volume when empty and it can be a regular tube which compressed. Its volume decreases to zero before liquid is injected into the container through the inlet fitting. Fluid is injected into the container at a pressure higher than P.O which is the pressure at which the normally closed valve opens. The volume of the fluid inside the container increases and so does its pressure. When the pressure inside the container increases to P.l which is lower than P.O. the injection of fluid stops, the pressure at the inlet drops to zero [atmospheric pressure] and the valve closes itself. At this stage the container stores a volume of fluid V at a pressure P.l. By pressing on the elastic tube the pressure inside the container increases to P.3 higher than P.O and the fluid flows out through the container outlet. When a volume dV flows out from the container, the volume of the container decreases by dV. When all the fluid stored in the container flows out from it, the pressure inside the container drops to zero yet no fluid can enter the container unless its pressure is higher than P.O. In order to press the elastic tube and cause the fluid to flow out, different means can be used as follow: - The elastic tube can be pressed by hand. - The container can be installed inside a vented flexible container which by pressing it the surrounding the elastic tube flows out through the casing-vent and the elastic tube is compressed. - By connecting an air pumping device to the casing described above.

Tvoe B. (23/2a + 23/2b)

The type B container consists of an insert surrounded tightly by an elastic tube. The insert and the elastic tube are formed by one normally closed valve at the fluid inlet and one normally closed valve at the outlet. The normally closed valve at the inlet has a higher preset pressure P.0/1 than the preset pressure P.0/2 of the valve at the outlet. The insert at the center section has an outside diameter D.l larger than the inside diameter D.O of the elastic tube.

At the "normally closed valve" of the inlet, the insert has an outside diameter D.2 which controls the pressure P.0/1 at which the fluid can enter into the container which is provided by the center section which has an outside diameter D.l smaller than D.2. At the "normally closed valve" of the outlet, the insert has an outside diameter D.3 which controls the preset pressure P.0/2 at which the valve at the outlet opens. D.3 is larger than D.l and smaller than D.2.

Fluid is injected into the container at a pressure P.l higher than P.0./1, the fluid flows to the center section which is the "receptacle container". The volume of liquid in the container increases and so does its pressure. When the pressure of the fluid in the container is at a level of P.3 slightly lower than P.0/2 the injection of the fluid into the container terminates.

The pressure at the inlet to the container drops to atmospheric pressure [zero] and the normally closed valve at the inlet closes itself, at this stage the container stores a volume v of fluid at a pressure P.3. By pressing on the elastic tube the pressure of the fluid in the container increases to P.4 which is higher than P.0/2 and lower than P.0/1 and a volume dV of the fluid flows out through the container outlet. The volume of the container decreases by dV from V.O to V.l and the pressure of the fluid inside the container decreases from P.3 to P.3/1. When all the fluid flows out from the container the pressure of the "last drop" is P.3/L. At this stage the elastic tube which has an inside diameter D.O smaller than D.l continues to press on the last drop at a pressure P.3/L. In order to eject the fluid from the container, the elastic tube can be pressed in different ways for example by using a flexible vented container which surrounds the container.

Tvoe c. (23/3a + 23/3b)

This container has the same design as container type B in which the normally closed valve at the outlet is replaced with a normally closed preset spring loaded valve as commonly used in aerosol containers. Pressurized fluid is ejected from the container through the valve nozzle when top of the valve is pressed. The receptacle can be installed inside any type of container. Fig. 24/1 illustrates a normally closed perforated elastic tube serving as a dripline for irrigating trees or other plants.

The drawing shows perforated elastic tube 24101 connected by means of a tee fitting 24102 to a dripper 24103 which is connected to irrigation lateral 24104. A normally closed valve or pulsating valve 24105 is connecting in parallel to dripper 24103 lateral 24104 and elastic perforated tube 24101. At any pressure P.l in lateral 24101 lower than the pre¬ set opening pressure P.O of valve 24105, valve 24105 stays closed and the water flows from the lateral 24101 through the ripper 24103 to the perforated elastic tube 24101. The pressure inside elastic tube 24101 increases, the perforations in the elastic tube opens to a degree at which the flow Q.l of the dripper 24103 can flow through the perforations in the elastic tube 24101. If elastic tube 24101 has N perforations, the average through each perforation is q.l = Q.l/N. When dripper 24103 is a pressure compensated dripper or a flow control, the flow Q.l is pressure compensated and does not change in response to pressure changes in the lateral 24104. When the pressure in lateral 24104 is P.2 higher than the pre-set pressure P.O of the valve 24105, water at a higher pressure and at a higher flow Q.2 enters the elastic tube 24104 through valve 24105. In response to pressure P.2 the elastic tube 24101 expands, its inside diameter increases, the size of the perforations increases to allow an average flow of q.2 to flow through each perforation and q.2 = Q.2/N. Such an arrangement allows the irrigation system to operate at a low pressure and at low flow Q.l per tree or at a higher flow Q.2 per tree and by increasing the pressure the perforations can be periodically flushed, eliminating them from plugging up.

Fig. 24/2 illustrates a normally closed perforated elastic dripline that can be used for irrigating any type of plants.

Elastic tube 24201 is connected by means of a dripper 24202 to lateral 24203 and a normally closed valve or pulsating valve 24204 is connected to lateral 24203 in parallel to dripper 24202.

End 24205 of elastic tube 24201 is plugged by means of a plug or normally closed valve 24206. Such elastic dripline operates as the dripline described above in Fig. 24/1.

When the pressure inside elastic tube 24201 increases, the inside diameter of the elastic tube 24201 increases and a higher flow can pass through the tube 24201. Normally closed valve 24206 can be used for periodically flushing the tube 24201.

Being normally closed the elastic tubes 24101 and 24202 described in Fig. 24/1 and in Fig. 24/2 can be installed below the ground surface.

Fig. 24/3 illustrates a perforated elastic tube in which the flow through each perforation is pressure compensated and as such stays the same regardless of the pressure inside the elastic tube. Such elastic perforated tube 24301 has a cross . section such that a section of it 24302 in which the perforation 24303 is made is caved into the center of the elastic tue 24301 and when he pressure inside the elastic tube 24301 increases, the caved portion 24302 is forced out rom the center and the size of the perforations becomes smaller thus controlling the flow through the perforation. At a certain pressure inside the elastic tube 24301, its cross section becomes round and at a higher pressure the elastic tube 24301 expands and the cross section of the perforations 24303 increases, the flow through the perforation 24303 increases and it is being flushed.

Claims

CIAIMS

1. Apparatus for converting pressurized low continuous liquid flow to a high intermittent pulsating flow which comprises a pressure container having a low elasticity means for supplying a continuous flow of liquid thereto at a controlled low flow rate and thereby establishing a pressurized body of liquid within said container, a pre-set normally closed valve connected to an outlet from said container, said valve remaining closed and preventing liquid from flowing out of the pressure container at a lower pressure and opening at a pre-set higher pressure at which liquid flows out of the container and closes itself at said lower pressure, whereby the outlet from the pressure container will remain closed until liquid flowing into the container causes pressure within the container to increase and the pre-set valve to reopen thus allowing for a volume of the liquid that was accumulated in the container when pressure was increased, to be ejected through container outlet and the pre-set valve, conduit means connected to the outlet of said pre-set valve, means associated with said conduit means providing sufficient resistance to liquid flow said pre-set valve, when it opens, to become widely open, thus allowing for liquid at a high rate of flow to be ejected from said container thereby causing the volume and pressure of the liquid within the container to decrease and said pre-set valve to close, said pre-set valve having a quick response as a result of said resistance whereby a "Water Hammer" effect is created thus causing the liquid to be ejected at a higher pressure and velocity than that of the incoming liquid flow.

2. Apparatus according to Claim 1 wherein the pre-set valve consists of an outer casing surrounding and spaced from a hollow insert having perforations in its side wall, an elastic sleeve covering tightly the outside of the insert and its perforations, additional perforations in the outer casing which are exposed to the surroundings of the pre-set valve, an expansion space between the outer casing and the sleeve, said expansion permitting said elastic sleeve to expand into said expansion space when pressure within the insert is increased, thus allowing liquid to flow from the insert out through its perforations and then between the inside of the sleeve and the outside of the insert and out through the outlet of the valve.

3. Apparatus according to Claim 2 wherein fluid surrounding the outer casing of the valve is drawn through the perforations therein to become mixed and ejected along with the liquid from the container.

4. Apparatus according to Claim 1 wherein the means for supplying continuous flow of liquid includes a pressure compensated dripper.

5. Apparatus according to Claim 1 in which pressure container is formed of a rigid material with low flexibility such that pressure increase within the container will cause some deformation and thereby increase its volume while under pressure.

6. An apparatus according to Claim 1, in which the container is made of rigid material and includes trapped air in a secondary container there within.

7. An apparatus according to Claim 1 in which the pressure container is made of non-elastic material.

8. An apparatus according to Claim 1, in which liquid flow to the pressure container is controlled by a non- compensated dripper. 82

9. An apparatus according to Claim 1 in which liquid flow to the pressure container is controlled by a small nozzle.

10. An apparatus according to Claim 1 in which outlet of the liquid flow controlling mean is connected to the inlet of the pressure container.

11. An apparatus according to Claim 1 in which liquid flow is controlled by a means incorporated within the pressure container.

12. An apparatus according to Claim 1 in which resistance to the flow is created by a small inside diameter tube connected to the outlet of the pre-set valve, which said tube has dimensions such as to permit said "Water Hammer" effect to occur.

13. An apparatus according to Claim 1 in which resistance to the flow is created by a long tube, connected to the outlet to the pre-set valve, said tube having a length sufficient to permit said "Water Hammer" effect to occur.

14. An apparatus according to claim 1 wherein resistance to liquid flow from the outlet of the valve is created by a small orifice connected to said outlet in the path of liquid flow therefrom, said orifice being sufficiently restricted to permit said "Water Hammer" effect to occur.

15. Apparatus according to Claim 1 wherein resistance to flow from the pressure container outlet is imparted by an elevated spray nozzle connected to said outlet by an elongated tube the length of which is sufficient to impart sufficient resistance to flow to permit said "Water Hammer" effect to occur.

16. Apparatus according to Claim 1 wherein resistance to flow of liquid from the pressure container outlet and the pre-set valve is created by means of a mechanical obstacle connected to the outlet of pre-set valve positioned in the path of said flow, said obstacle restricting said flow sufficiently to permit said "Water Hammer" effect to occur. ,

17. A sprinkler in which a pressurized low continuous liquid flow is converted to a high intermittent pulsating flow which comprises a pressure container having low elasticity in the form of a spike, means for supplying a continuous flow of liquid thereto at a controlled low flow-rate by means of a pressure compensated dripper and thereby establishing a pressurized body of liquid within said container, a pre-set normally closed valve connected to an outlet from said pressure container said valve having an elastic sleeve within a perforated casing, said valve remaining closed and preventing liquid from flowing out of said pressure container at a lower pressure and opening at a pre-set higher pressure whereby the outlet from said pressure container will remain closed until liquid flowing into the container causes pressure therein to increase and the pre-set valve to open this allowing for a volume of the liquid that accumulated in the container while pressure was being increased to be ejected through the container outlet and valve, and a spray device connected to the outlet of said valve by means of a small inside diameter tube, thereby providing a sprinkler in which liquid is ejected at a high pressure created by "Water Hammer" resulting from a quick response of the pre-set valve while permitting air to be drawn through said perforations to become mixed and ejected with the liquid.

18. A plurality of sprinklers according to Claim 17 in which each has a pre-set valve with a different opening pressure connected to the same irrigation system and controlled by changing pressures in the irrigation system.

19. A plurality of sprinklers according to Claim 17 connected by a common tube to one or more common drippers.

20. Apparatus according to Claim 3 wherein the ejection and mixing of fluid surrounding the outer casing of the valve functions as a fluid injection pump operating at a low flow.

21. Apparatus according to Claim 1 in which a liquid at a low flow rate is sprayed over a designated area by means of a spray nozzle connected to the outlet of the valve.

22. A spray device according to Claim 3 in which the pressure compensated dripper controls and pressure compensates the ejected flow from the spray device.

23. A method for converting pressurized low continuous liquid flow to a high intermittent pulsating flow which comprises supplying liquid at a constant continuous relatively controlled rate to a closed chamber having low elasticity having inlet and outlet means and establishing a body of liquid under pressure therein, preventing outflow of liquid through said outlet means until a designated pre-determined pressure is achieved, then allowing said liquid to flow out from said chamber through said outlet means until the pressure is diminished to a predetermined level while at the same time restricting said outflow sufficiently to create a "Water Hammer" effect to generate a high pressure liquid pulse and at that point quickly discontinuing emission of liquid until pressure within said chamber is again increased to said pre-determined level and repeating said sequence repeatedly for a desired period of time to achieve said intermittent pulsating effect.

24. A method according to Claim 23 wherein the liquid is water wherein said water is discharged adjacent to growing plants for irrigation purposes.

25. A method according to Claim 24 wherein the outflow of said water is quickly interrupted during each cycle to cause pressurized ejection thereof by means of said "Water Hammer" effect created thereby, in the form of a spray.

26. A sprinkler according to Claim 17 wherein the spike is divided into upper and lower sections which encompass and communicate with a liquid conduit which passes between said sections together with the dripper positioned there within.

27. A sprinkler according to Claim 17 wherein a plurality of said spike units are positioned at spaced intervals along said conduit.

28. Apparatus according to Claim 1 wherein the pressure container is in the form of a section of flexible tubing connected to a liquid supply means at its inlet and to said valve at its outlet.

29. Apparatus according to Claim 2£ wherein said flexible tubing is supported in an elevated position by means of a vertical rod connected at its upper end to said valve.

30. Apparatus according to Claim 2 wherein the pressure container is provided within the valve structure itself due to accumulation of fluid between the said elastic member and the said insert in response to the increase in pressure.

31. Apparatus according to Claim 30 wherein said elastic member surrounds tightly also outlet of said apparatus thus creating a receptacle between said elastic member and said insert along a section of the apparatus between its normally closed sections at the inlet and its normally closed section at the outlet, pulsating flow.

32. valve structure which comprises an elastic tubular member defining a passage for fluid flow therethrough, inlet and outlet fittings engaged by the ends of said elastic member and means for subjecting said elastic member to elastic deformation to cause modification of the dimensions of said passage in response to fluid pressure applied thereto.

33. A normally open valve structure according to Claim 32 wherein said elastic member is positioned within and concentric with a rigid tubular member, and means for admitting a fluid under pressure into said rigid member to cause elastic compression of said elastic member and thereby restrict said passage.

34. A normally open valve structure according to Claim 33 wherein the elastic member is positioned within and concentric with a rigid tubular member, a rigid insert is positioned within and spaced from the walls of said elastic members to allow normally open fluid to flow through said elastic member, and means for introducing fluid under pressure into said rigid tubular member to cause elastic deformation of said elastic member and contact with said insert to close or restrict flow throughsaidelasticmember.

35. A normally closed valve according to Claim 32 having pulsating characteristics wherein a low continuous fluid flow can be converted to a high pulsating flow ejected therethrough which comprises a rigid insert positioned within said elastic member said insert having a diameter greater than said elastic member whereby it is stretched tightly there over, said elastic member being affixed to said insert at each end thereof, said insert having inlet and outlet openings in communication with the inner surface of said elastic member, whereby expansion of said elastic member occurs when inlet fluid pressure is increased sufficiently to cause expansion of said elastic member and fluid flows between it and said insert accumulating in a receptacle created between the elastic tube and the insert and when the pressure within said receptacle increases sufficiently to cause expansion of the elastic tube at the outlet and fluid flows from the receptacle through said outlet, and an hydraulic resistance to the flow is causing the elastic tube at the outlet to expand and the fluid than to flow at a high flow from the receptacle while fluid flows into the receptacle at a low flow and as a result of which the volume of fluid in the receptacle decreases, the pressure of fluid in the receptacle decreases, the elastic member contracts sealing the openings of the insert at the fluid inlet to the receptacle terminating one pulsating cycle.

36. A normally closed pulsating valve according to Claim 11 in which the elastic member and its insert are enclosed in a rigid casing having a vent opening therein, said casing having an inside diameter such that the expansion of the elastic member is restricted thereby creating conditions for production of a "Water Hammer" effect in response to quick response of the valve resulting in ejection of fluid at high pulsating flow and at high velocity or pressure.

37. A normally closed pulsating valve according to Claim 36 in which, a deflector is affixed to the outlet for controlling the pattern of the ejected fluid.

38. A normally closed pulsating valve according to Claim 37 in which the deflector is integral with the insert.

39. A valve structure according to Claim 35 which functions as a self-cleaning filter wherein the elastic member is partly perforated and during its filtering stage fluid that enters the valve through its inlet flows out through the perforations in the elastic member to the space surrounding the elastic member and out through a port in the valve casing and when the perforations get plugged up, a receptacle is created and the valve operates as a pulsating valve ejecting the fluid and the solid particles from the receptacle out through the valve outlet flushing and cleaning the filter.

40. A valve structure according to Claim 35 which functions as a fluid driven injection pump in which a main fluid that flows through the valve is causing it to pulsate, the elastic tube inside the casing expands and contracts causing a second fluid to enter the casing, compressed, eject and mixed with the main fluid at the outlet of the valve.

41. A valve according to Claim 35 which functions as a fluid driven pump where the casing of the pulsating valve has a second port through which a second fluid that enters the venting port in the casing is ejected at elevated pressure.

42. A pumping system which incorporates a valve structure according to Claim 39 wherein water from a reservoir flows by gravity into the casing of the pump mixed and eject with the water that flows into the valve at a certain flow causing it to pulsate and ejects through the pump outlet at a higher flow thus pumping water from the reservoir.

43. A pumping system which incorporates a valve structure according to Claim 40 wherein water from a reservoir flows by gravity into the casing of the pump and eject at elevated pressure through a second port in the casing when water flows through the pump causing it to pulsate.

44. A valve structure according to Claim 40 which functions as a soaping device wherein a container with liquid soap is connected to the secondary fluid discharge outlet of a fluid driven pump which its main inlet is connected to a faucet which when turned on discharge water into the valve causing it to pulsate and forcing air to enter the casing of the valve,flow through the soap in the container,converted it to foam which ejects and mixed with the water that ejects from the main outlet of the valve.

45. A pulsating liquid spryer according to Claim 36 where a spray head is connected to the outlet from the valve.

46. A pulsating sprinkler according to Claim 45 where the spray head is a sprinkler.

47. A pulsating drip line according to claim 35 where the inlet to a drip line is connected to the outlet from a pulsating valve.

48. A frost control method and apparatus which comprises a sheath substantially enclosing a plant and means for applying a small application rates of water by means of a pulsating minisprinkler according to Claim 44 forming a fine layer of water which is retained thereby and converted to ice when a freezing temperature is reached thereby creating a protected zone about said plant.

49. A self cleaning low flow pulsating pop-up sprinkler comprising an outer hollow cylindrical casing open at one end and provided with a liquid inlet at the other end, a hollow cylindrical riser with a pulsating sprinkler, according to claim 44, hood positioned within said casing said riser being shorter in length than said casing and a positioned therein to be spaced therefrom and concentric therewith, the base of said riser being provided with a cylindrical screen filter with a gasket such as "0-ring" positioned around said .riser above said screen, and an outlet fitting positioned within said casing at a selected intermediate point therein adapted to be engaged by said gasket when the riser is in elevated position, whereby liquid flowing into the inlet of said casing will flush said screen and cause the riser to rise until it contacts said outlet fitting at which point the liquid will flow through said screen and riser to said sprinkler head.

50. A Normally open hydraulic valve structure according to

Claim 32 wherein said elastic member is held at a fixed place at both of its ends by surrounding tightly an inlet and outlet fluid fittings and the elastic tube is positioned within a tubular casing having a port through which the space surrounding the elastic tube can be pressurized, causing the elastic tube to become flat with its walls pressed against each other preventing from a fluid to flow through it thus closing the valve or vented causing the elastic tube to become round and permitting a fluid to flow freely through it thus maintaining the valve open.

51. A normally open hydraulic valve structure according to Claim 32 wherein the elastic tube is positioned within concentric and rigid tubular casing and rigid insert is positioned within the elastic tube and spaced from the walls of said elastic member to allow, at the normally open position of the valve a free fluid flow through said elastic member, and a port for introducing fluid under pressure into said rigid tubular casing to cause deformation of said elastic tube causing it to contract and surround tightly said insert and prevent a fluid to flow through the elastic tube and thus closing the valve and when said port is vented, the elastic tube expands and becomes round permitting fluid to freely flow through the elastic tube thus maintaining the valve open.

52. A normally closed valve structure according to Claim 33 where the elastic member is positioned within concentric rigid casing, and a rigid insert having a fluid inlet and a fluid outlet is positioned within the elastic tube which is held at fixed place at both of its ends by surrounding tightly the insert which its center section has an outside diameter larger than the inside diameter of the elastic tube which as such surrounds tightly this portion of the insert preventing from fluid at a low pressure to flow from the inlet to the outlet and when the pressure of the fluid at the inlet increase,the elastic tube expands its inside diameter increases and becomes larger than the outside diameter of the insert at its center portion and fluid than flows from the inlet through the elastic tube to the outlet.

53. A normally closed preset pressure responsive valve structure according to claim 33 wherein the elastic member is positioned within a rigid tubular enclosure and spaced therefrom, and comprises a rigid insert surrounded by and tightly engaged within the walls of said elastic member which is stretched there over, a fluid inlet opening within one end of said insert, said opening communicating with said elastic member at one end thereof, a fluid outlet opening in said insert at the other end thereof communicating with said elastic member of the other end thereof, whereby fluid under pressure which enters said inlet opening can cause elastic expansion and separation of said elastic member from said insert to permit flow therebetween and removal through said outlet opening, and an opening in the wall of said rigid tubular member to permit release of pressure caused by expansion of said elastic member.

54. A normally closed pressure responsive valve structure according to Claim 1 wherein the elastic tubular member surrounds and tightly engages a rigid insert, said insert having an elongated opening therein forming a fluid inlet, laterally expanding openings from said elongated opening communicating with said elastic member, said insert having an enlarged diameter near the base thereof over which the lower portion of said elastic member is tightly stretched and mounted, said insert with said elastic member mounted thereon being positioned within a rigid tubular member and concentric therewith and affixed to its base, an opening at the top of said rigid tubular member, said elongated opening and said laterally extending openings permitting fluid under pressure to expand said elastic member away from said insert to permit fluid to flow outward through said opening at the top of said rigid tubular member.

55. A normally closed pressure responsive valve structure according to Claim 54 wherein said insert extends out from said opening in said rigid tubular member and wherein said extension supports a fluid deflector positioned to deflect fluid in the form of a spray.

56. A normally open valve according to Claim 33 having flow regulating characteristics which comprises a rigid tubular enclosure, inlet and outlet fittings positioned respectively at each end thereof, an elastic tubular member positioned within said enclosure and spaced concentrically therefrom, said elastic member being affixed at each end respectively to said inlet and outlet fittings, inlet and outlet . openings extending respectively through said fittings communicating with the interior of said elastic member for the circulation therethrough of a fluid under pressure a separate opening extending through said inlet fitting communicating with the space between said elastic member and said disclosure for the introduction of other fluid under predetermined pressure, whereby flow control may be effected by the pressure differential between the inside of the elastic member and its surrounding area in response to elastic deformation of said elastic member.

57. A normally open valve according to Claim 33 having flow control characteristics which comprises a rigid enclosure open at one end, a rigid insert fitted within said open end said insert having an inlet opening leading into said enclosure, an elastic tubular member positioned within said enclosure between the insert and the closed end thereof and spaced from the inner walls of said enclosure said elastic member defining inlet and outlet passages which communicate with said inlet opening, and openings within the closed end of said enclosure communicating with the outlet passage of said elastic member, whereby fluid under pressure can circulate through the tubular elastic member while said elastic member is surrounded by fluid in order that as fluid flow through said tube increases a resulting pressure drop will cause compression of said elastic member from said surrounding fluid.

58. A receptacle which comprises a normally closed preset pressure response valve structure according to Claim

32 wherein such valve member has a receptacle closure in the form of an insert having an inlet opening which includes lateral side passages extending to the edge thereof, said insert being incorporated within and tightly surrounded by the open end of a collapsed flexible elastic tubular member which is closed at its other end whereby fluid introduced through said inlet opening and said passages at sufficient pressure to separate said elastic member at the juncture with said insert to flow into the bottom portion of said collapsed tube to be retained therein.

59. A receptacle according to claim 32 having a preset pressure response valve structure at its inlet and a preset pressure response normal closed valve structure at its outlet comprises an elastic tubular member having an inlet opening and an outlet opening, an elongated rigid insert coextensive with and surrounded by said elastic member said insert having an outside diameter greater than the inside diameter of said elastic member and being tightly engaged thereby, said insert at the inlet position of said elastic member having a passageway for inlet fluid leading to the inner surface of said elastic tube in contact therewith, the diameter of said insert at said inlet position being predetermined to permit fluid to cause separation of said elastic member therefrom and fluid to enter said elastic member, at a predetermined inlet pressure and accumulate therebetween said insert at the outlet position of said elastic member having a passageway for outlet fluid leading to the inner surface of said elastic member, the diameter of said insert at outlet position from said insert at a predetermined outlet pressure and release of fluid accumulated between said insert and said elastic member.

60. An apparatus according to claims 1 and 32 in which the elastic member is elastic tube.

61. An apparatus according to claims 32 in which the casing and the elastic member are one part which consist of tube having a shape of a pipe within a pipe where the outside portion of the tube is serving as a casing and the inside portion of said tube is serving as elastic member.

62. An apparatus according to Claim 1 and 32 where the casing is a tube and the insert with said elastic member are surrounded by said tube.

63. An apparatus according to claim 62 in which said insert and elastic member are inserted into said elastic tube during the extrusion of the tube.

64. A limiting valve structure according to Claim 32 wherein the inlet of the normally closed valve which opens at a given preset pressure is connected to the outlet of a normally open valve having a preset closing pressure higher than the pre-set opening pressure of the normally closed valve whereby fluid can flow through the combined valves only when its pressure at the inlet to the combined valve is within a limited range of pressures.

65. A control method and apparatus comprising a limiting pressure range valves according to Claim 64 and or normally closed valves and or normally open valves connected to different outlets from the same pipe or system are controlled separately in respond to pressure changes at the pipe.

66. A pre-perforated normally closed elastic member that when the pressure of a fluid enclosed inside said member is low the perforations in said member are closed and at higher fluid pressure within said elastic member,the walls of said elastic member expands, the perforations opens and the fluid flows from the enclosed pressurized space in the elastic member, through the perforations out to the space surrounding said elastic member.

67. An apparatus according to Claim 66 where said elastic member is elastic perforated tube plugged at its end.

68. An apparatus according to Claim 67 where said perforated elastic tube is a drip irrigation tube.

69. A normally closed dripline according to Claim 68 in which irrigation water flows to its inlet through a dripper.

70. A normally closed dripline according to Claim 69 in which said dripper is a pressure compensate dripper or a flow control.

71. A normally open pulsating valve according to claim 32 where the elastic tubular member is enclosed in a casting and the space surrounding the elastic tube is connected with the fluid inlet to the elastic member thus a fluid that enters said valve has the same pressure at sad elastic member fluid inlet and at the space surrounding said member and a pressure drop along said elastic member causes it to close and open itself and a fluid that enters the valve at a low continuous flow is ejected form the valve at high intermittent pulsating flow.