WO2018096528A1

WO2018096528A1 - Drip irrigation emitter, an irrigation pipe with a plurality of such emitters and method for producing such emitters

Info

Publication number: WO2018096528A1
Application number: PCT/IL2017/051260
Authority: WO
Inventors: Nimrod ARI; Gil Rafael Tsouri
Original assignee: Terracuity Technologies Ltd.
Priority date: 2016-11-23
Filing date: 2017-11-19
Publication date: 2018-05-31
Also published as: IL249153A0

Abstract

A drip irrigation emitter comprising an emitter inlet, an emitter outlet, an irrigation fluid path extending therebetween including a pressure-reducing mechanism configured to convert fluid flow entering the emitter inlet under pressure, into a drip flow from the outlet; a space via which the pressure reduced fluid has to pass in order to reach the emitter outlet; and a mechanism based on a fluid-accumulation chamber which is configured for being brought into fluid communication with an exterior of the emitter for receiving therefrom at least indirectly an accumulatable fluid and further configured to allow introduction of the accumulatable fluid into a chamber to cause the chamber to change over time its state between a first state, in which the amount of said accumulatable fluid in the chamber is minimal and a second state, in which the amount of the accumulatable fluid in the chamber is maximal and in which fluid communication between the pressure-reducing mechanism and the emitter outlet is prevented, wherein the emitter is characterized by a further one-way valve having a valve inlet downstream from the pressure-reducing mechanism and a valve outlet upstream to said space and configured to allow the drip flow from the valve outlet into said space as long as fluid pressure differential between the valve inlet and the valve outlet is not less than an operational pressure differential, and wherein the a fluid-accumulation chamber mechanism is configured to change a state of the fluid irrigation path between a first, operational state allowing said drip flow via said valve and said space towards the emitter outlet, and a second state in which fluid communication is prevented between said space and the emitter outlet, causing the pressure differential at said valve to drop below the operational pressure differential.

Description

DRIP IRRIGATION EMITTER, AN IRRIGATION PIPE WITH A PLURALITY OF SUCH EMITTERS AND METHOD FOR PRODUCING SUCH EMITTERS

TECHNOLOGICAL FIELD

The presently disclosed subject matter is directed to the field of drip irrigation and, particularly, to the control of amount of fluid dispensed by a drip irrigation emitter when mounted in or on a drip irrigation pipe.

BACKGROUND

Drip irrigation emitters are commonly comprised of an inlet, an outlet and a pressure- reducing mechanism therebetween configured to convert fluid flow entering the emitter inlet under pressure, into a drip flow from the emitter outlet. The emitter is connected to an irrigation pipe to draw fluid through its inlet and dispense it to the outside environment by dripping from its outlet. Patents US 3,753,527 ; US 4,317,539 ; US 3,954,223 are representative examples of existing emitters following the aforementioned description.

Typically, multiple drip irrigation emitters are connected externally or internally to an irrigation pipe and multiple such irrigation pipes are spaced apart on the ground to irrigate areas.

GENERAL DESCRIPTION

The presently disclosed subject matter constitutes a modification of the subject matter described and claimed in PCT Application No. PCT/IL2016/050633 of the Applicants.

According to one aspect of the presently disclosed subject matter, there is provided a drip irrigation emitter comprising:

an emitter inlet, an emitter outlet, an irrigation fluid path extending therebetween and comprising

o a pressure-reducing mechanism configured to convert fluid flow entering the emitter inlet under pressure, into a drip flow from the outlet;

o a space via which the fluid has to pass in order to reach the emitter outlet; and o a valve having a valve inlet downstream from the pressure-reducing mechanism and a valve outlet upstream to said space and configured to allow the drip flow from the valve outlet into said space as long as fluid pressure differential between the valve inlet and the valve outlet is not less than an operational pressure differential, and

a mechanism configured to change a state of the fluid irrigation path between a first, operational state allowing said drip flow via said valve and said space towards the emitter outlet, and a second state in which fluid communication is prevented between said space and the emitter outlet, causing the pressure differential at said valve to drop below the operational pressure differential.

In accordance with a further aspect of the presently disclosed subject matter, there is provided a method for producing a drip emitter, comprising inter alia, providing the emitter with the mechanism and the valve as defined above and, optionally having features described below.

The above mechanism can be in the form of a fluid-accumulation chamber configured for being brought into fluid communication with an exterior of the emitter for receiving therefrom at least indirectly an accumulatable fluid and further configured to allow introduction of the accumulatable fluid into the chamber to cause the chamber to change its state between a first state, in which the amount of said accumulatable fluid in the chamber is minimal and a second state, in which the amount of the accumulatable fluid in the chamber is maximal and in which fluid communication between said space and the emitter outlet is prevented, causing the pressure differential at said valve to drop below the operational pressure differential.

In the first state of the chamber, it can be free of said accumulatable fluid.

In the second state of the chamber, the maximal amount of the accumulatable fluid can be such that fluid communication between the pressure -reducing mechanism and the emitter outlet is completely prevented, i.e. the flow rate through the outlet equals zero. This maximal value of the amount of the accumulatable fluid in the chamber can be selected so as to ensure that it is reached only after a predetermined amount of irrigation fluid has been dispensed from the emitter outlet. The maximal amount of the accumulatable fluid can be selected so as to ensure that this amount is reached only when a predetermined level of moisture has been reached at the exterior of the emitter outlet.

The drip irrigation emitter can comprise a housing having a housing front surface and a housing rear surface, the housing front surface being formed with said emitter inlet and the housing rear surface being formed with a housing outlet. In this case, the housing comprises a first part of said irrigation fluid path extending between said emitter inlet and the housing outlet, with said pressure -reducing mechanism and the valve therebetween. The housing can further comprise a cover formed with said emitter outlet, the cover being so assembled with the housing as to form a space between the housing rear surface and the emitter outlet, said space constituting a second part of said irrigation fluid path. This space can be configured to accommodate said chamber at least in the second state.

The fluid-communication chamber can comprise at least one chamber orifice configured for being in fluid communication with an exterior of the emitter for receiving therefrom the accumulatable fluid and for introduction of such fluid into the chamber. The orifice of the chamber can be in fluid communication with the emitter inlet via an accumulatable fluid path, so as to allow fluid entering the emitter via said emitter inlet to simultaneously flow along the first part of the irrigation fluid path and along the accumulatable fluid path, which can comprise a pressure-reducing mechanism partially or completely different from that of the irrigation fluid path.

The chamber can have an interior filled with a moisture- sensitive material, in which case its orifice can be in fluid communication with an exterior of the emitter at least at one location in the housing other than the emitter inlet such as to prevent fluid communication of the orifice with the emitter inlet.

The drip irrigation emitter can be of an on-line type, i.e. configured for being mounted onto an exterior surface of an irrigation pipe so as to provide fluid communication of the emitter inlet with an interior of the irrigation pipe, or of an in-line type, i.e. configured for being integrally attached to an interior surface of an irrigation pipe so as to provide fluid communication of the emitter inlet with an interior of the irrigation pipe and of the emitter outlet with an exterior of the pipe.

In accordance with a further aspect of the presently disclosed subject matter, there is provided an irrigation pipe comprising a plurality of drip irrigation emitters of the kind described above, disposed at different distances from a location, at which the pipe is configured to receive therein pressurized irrigation fluid. The irrigation pipe can be operable at least at one fluid pressure at said location so that, once said chamber is in its second state in at least one of the drip emitters, at least some of the remaining drip emitters will experience an increased pressure of fluid at their inlets.

In accordance with a still further aspect of the presently disclosed subject matter, there is provided an irrigation pipe comprising a plurality of drip irrigation emitters disposed at different distances from a location, at which the pipe is configured to receive therein pressurized irrigation fluid, each emitter comprising:

- an emitter inlet, an emitter outlet, an irrigation fluid path extending therebetween and comprising

o a pressure-reducing mechanism configured to convert fluid flow entering the emitter inlet under pressure into a drip flow from the outlet,

o a space via which the fluid has to pass in order to reach the emitter outlet; and

o a valve having a valve inlet downstream from the pressure-reducing mechanism and a valve outlet upstream to said space, and configured to allow the drip flow from the valve outlet into said space as long as fluid pressure differential between the valve inlet and the valve outlet is not less than an operational pressure differential, and

a mechanism configured to change a state of the fluid irrigation path between a first, operational state allowing said drip flow via said valve and said space towards the emitter outlet, and a second state in which fluid communication is prevented between said space and the emitter outlet, causing the pressure differential at said valve to drop below the operational pressure differential;

so that at least at one fluid pressure at said location, at least once the state of the irrigation fluid path reaches its second state in at least one of the drip emitters, at least some of the remaining drip emitters will experience an increased pressure of fluid at their inlets. BRIEF DESCRIPTION OF THE DRAWINGS

In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

Fig. 1 is a schematic illustration of a drip irrigation emitter with its fluid-accumulating chamber in its first state, according to an example of the presently disclosed subject matter.

Fig. 2 is a schematic illustration of the drip irrigation emitter of Fig. 1 with fluid- accumulating chamber in its second state.

Fig. 3 is an illustrative example of a drip irrigation system making use of any drip irrigation emitter of the presently disclosed subject matter.

Fig. 4 is a schematic illustration of an on-line drip irrigation emitter, in accordance with one embodiment of the presently disclosed subject matter.

Fig. 5 is a first exploded view of the emitter of Fig. 4.

Fig. 6 is a second exploded view of the emitter of Fig. 4.

Fig. 7 is a side view of a housing of the emitter of Fig. 4 with fluid-accumulating chamber in its second state.

Fig. 8 illustrates one example of an interior, which a housing of the emitter of Fig. 4 can have, between front surface of the housing and rear surface of the housing.

Fig. 9 shows a housing of an on-line drip irrigation emitter, in accordance with another embodiment of the presently disclosed subject matter.

Fig. 10 illustrates interior of the emitter of Fig. 9 between front surface of housing and rear surface of housing.

Fig. 11 is an exploded view of an integral drip irrigation emitter, in accordance with yet another embodiment of the presently disclosed subject matter.

Fig. 12 is a side view of a housing of the emitter of Fig.1 1 with its fluid-accumulating chamber in its second state.

Fig. 13 is an exploded view an integral drip irrigation emitter, in accordance with a yet another embodiment of the presently disclosed subject matter.

Fig. 14 is a side view of a housing of the emitter of Fig. 13 with its fluid-accumulating chamber in its second state.

Fig. 15 illustrates another example of an interior, which the housing of the emitter of Fig. 4 can have, between front surface of housing and rear surface of housing. Fig. 16 is an exploded view of an integral drip irrigation emitter, in accordance with yet another embodiment of the presently disclosed subject matter.

Fig. 17A and Fig. 17B are top and bottom views of a single diaphragm integrating multiple functions, in accordance with yet another embodiment of the presently disclosed subject matter, with a fluid-accumulating chamber portion of the diaphragm being in its first state.

Fig. 18 is a top view of the diaphragm shown in Fig. 17A, with its fluid-accumulating chamber portion being in its second state.

DETAILED DESCRIPTION OF EMBODIMENTS

Fig. l schematically shows one example of a drip irrigation emitter 10 of the presently disclosed subject matter. The drip irrigation emitter 10 comprises an emitter inlet 11, an emitter outlet 12 and an irrigation fluid path extending therebetween including a pressure- reducing mechanism 13, a valve 17 and a space 18 adjacent to the emitter outlet 12, the valve 17 having a valve inlet 17' (not seen) downstream from the pressure -reducing mechanism 13 and a valve outlet 17" upstream to the space 18. The drip irrigation emitter 10 further comprises a sealed fluid-accumulation chamber 14 disposed within the space 18 and having at least one chamber orifice 15 in fluid communication with emitter's exterior via accumulatable fluid path 16. The sealed fluid-accumulation chamber 14 is presented in its first state of being free of accumulatable fluid. Fig.2 shows drip irrigation emitter 10 with the fluid-accumulation chamber 14 in its second state of containing a predetermined amount of accumulatable fluid.

The valve 17 is configured to pass fluid therethrough from the pressure-reducing mechanism 13 to the space 18 as long as pressure differential between its inlet and outlet is not lower than its predetermined operational pressure differential. Thus, when pressurized fluid from an irrigation pipe (not shown in Figs. 1 and 2) enters the emitter inlet 11, the pressure-reducing mechanism 13 converts fluid flow to a drip flow, which enters the valve 17, and when the pressure differential between the valve inlet 17' and the valve outlet 17" rises until it reaches the operational pressure differential, the valve 17 allows drip flow therethrough into the space 18 and out of the emitter outlet 12. When the accumulatable fluid path 16 introduces accumulatable fluid to the sealed fluid-accumulation chamber 14 via the chamber orifice 15, the sealed fluid-accumulation chamber 14 transitions from its first state of being free of accumulatable fluid and allowing drip flow through outlet 12 to its second state of containing a predetermined amount of accumulatable fluid and preventing drip flow through outlet 12. Once drip flow is prevented from the outlet 12, the fluid pressure in the space 18 surrounding the fluid-accumulation chamber 14 rises until the pressure differential between the valve inlet 17' and the valve outlet 17" becomes too low to allow fluid flow therethrough. At this point, fluid ceases to flow from the valve outlet 17", with the fluid- pressure at the space 18 remaining below the fluid-pressure at the inlet 11. Simultaneously, the fluid pressure inside the fluid-accumulation chamber 14 rises, as the accumulatable fluid path 16 introduces additional accumulatable fluid to the sealed fluid-accumulation chamber 14 via the chamber orifice 15, until it is higher than the fluid pressure at the remaining space 18 surrounding it, thereby allowing the sealed fluid-accumulation chamber 14 to block in a stable manner the flow from the space 18 to the outlet 12 until pressure in the irrigation pipe is dropped and the fluid accumulation chamber 14 returns to its first state by discharging its content to the exterior of drip irrigation emitter 10 from the chamber orifice 15 via the accumulatable fluid path 16 thereby reverting back to its first state of being free of accumulatable fluid.

Fig. 3 shows a drip irrigation system 50 comprised of a main fluid line 51, an optional flow controller 52, an optional pressure and/or flow meter 53, a secondary fluid line 54 and a network of pipes 55 each with a plurality of drip irrigation emitters 10 of a kind similar to the emitter 10 described above, disposed at different distances from the location where the pipes 55 receive pressurized irrigation fluid from the secondary fluid line 54. The pipes 55 may cover great distances and/or varying topography.

When at least some of the fluid- accumulation chambers 14 of the emitters 10 are in their first state and the irrigation system 50 introduces pressurized fluid to the pipes 55, the emitters 10 along the pipes 55 experience varying fluid pressure at their inlets 11 depending on on their distance from the secondary fluid line 54 and their topographical position. Over time, the fluid-accumulation chambers 14 of some of the emitters 10 along the pipes 55 transition to their second state, thereby increasing the pressure of fluid at the inlets 11 of the emitters along the pipes 55 whose fluid-accumulation chamber 14 is still in its first state. Eventually, all the fluid-accumulation chambers 14 of the emitters 10 along the pipes 55 transition to their second state. When the system 50 stops introducing pressurized fluid to the secondary fluid line 54. The fluid-accumulation chambers 14 of the emitters 10 along the pipes 55 revert to their first state according to their discharge configuration. The operation of irrigation system 50 described above constitutes one example of an irrigation cycle and may be repeated depending on irrigation needs.

Fig. 4 shows one embodiment of the presently disclosed subject matter in the form of an on-line drip irrigation emitter 20 designed so that its fluid-accumulation chamber transitions to its second state only when a predetermined amount of irrigation fluid has been dispensed from the emitter's outlet.

Fig. 5 shows a first exploded view of drip irrigation emitter 20 comprising a housing 22 and a cover 23. The housing 22 has a housing front surface formed with the inlet nozzle 25. The cover 23 has an interior and an emitter outlet 26.

Fig. 6 shows a second exploded view of the drip irrigation emitter 20 with the inlet nozzle 25 pointing away from viewer. The housing 22 comprises a valve 27 in its rear surface and a chamber orifice 28 sealed by an expandable membrane forming with an adjacent portion of the housing surrounding the orifice 28 a fluid-accumulation chamber 29 presented in its first state of being free of fluid. Fig. 7 shows a side view of the housing 22 when the fluid-accumulation chamber 29 is in its second state of containing a predetermined amount of accumulatable fluid.

When housing 22 and cover 23 are assembled, the interior of cover 23 forms a space between the housing rear surface and the emitter outlet 26.

Fig. 8 shows interior of the housing 22 between the front surface of the housing 22 and rear surface of the housing 22. The inlet nozzle 25 leads to the channel 30 that splits into an irrigation fluid path and an accumulatable fluid path. The first part of the irrigation fluid path is from the channel 30 to the valve 27 through the pressure-reducing labyrinth 33 in the interior of the housing 22 and through the channel 32. The second part of the irrigation fluid path is from the valve 27 to the emitter outlet 26 through the space formed in interior of the cover 23. The accumulatable fluid path is from the channel 30 to the fluid-accumulation chamber 29 through the pressure-reducing labyrinth 31, the channel 34 and the chamber orifice 28.

The inlet nozzle 25 is designed to be inserted into an irrigation pipe. When an irrigation cycle starts, the pressurized fluid entering the inlet nozzle 25 from the irrigation pipe flows from the channel 30 to the inlet of valve 27 through the pressure-reducing labyrinth 33 and the channel 32. The fluid pressure differential between inlet and outlet of the valve 27 increases until it reaches the operational pressure differential resulting in a drip flow from the outlet of the valve 27 into the empty space surrounding the fluid-accumulation chamber 29 and enclosed by the interior of cover 23 and from the drip flow continues to the outside environment through the emitter outlet 26. Simultaneously to the drip flow from the emitter outlet 26, the pressurized fluid in the irrigation pipe flows through the accumulatable fluid path from the channel 30 to the fluid- accumulation chamber 29 through the pressure- reducing labyrinth 31, the channel 34 and the chamber orifice 28.

As time progresses during the irrigation cycle, the fluid-accumulation chamber 29 accumulates fluid and fills the space enclosed by the interior of cover 23. When the fluid- accumulation chamber 29 accumulates a fluid amount that expands the fluid-accumulation chamber 29 sufficiently to block the emitter outlet 26, it transitions from its first state of being free of accumulatable fluid and allowing drip flow from the emitter outlet 26 to its second state of containing a predetermined amount of fluid and blocking drip flow from the emitter outlet 26. The fluid pressure in the remaining space surrounding the fluid-accumulation chamber 29 and enclosed by the interior of cover 23 rises until the pressure differential between the inlet and outlet of the valve 27 becomes too small to allow fluid flow therethrough. At this point, fluid flow ceases from the outlet of the valve 27 and the fluid- pressure at the remaining space surrounding the fluid-accumulation chamber 29 and enclosed by the interior of cover 23 remains below the fluid-pressure at the inlet nozzle 25. Simultaneously, the fluid pressure inside the fluid- accumulation chamber 29 rises to the fluid pressure at the inlet nozzle 25. The fluid pressure inside the fluid- accumulation chamber 29 is higher than the fluid pressure at the remaining space surrounding it ensuring a stable blocking of fluid flow from the emitter outlet 26. The fluid- accumulation chamber 29 remains in its second state, thereby continuing to block flow from the emitter outlet 26, as long as the irrigation pipe remains pressurized.

When the irrigation cycle is complete and fluid pressure at the inlet nozzle 25 drops, the fluid-accumulation chamber 29 contracts and discharges its fluid content through the chamber orifice 28 back into the irrigation pipe through the channel 34, the labyrinth 31, the channel 30 and the inlet nozzle 26. At the end of this discharging process, the fluid- accumulation chamber 29 reverts back to its first state of being free of accumulatable fluid.

Fig. 9 shows yet another embodiment of the presently disclosed subject matter in the form of an on-line drip irrigation emitter having housing 60 with the fluid-accumulation chamber 63 in its first state of being free of accumulatable fluid. The housing 60 is designed so that its fluid-accumulation chamber 63 transitions to its second state only when a predetermined level of moisture has been reached at the exterior of the emitter.

The housing 60 is a modification of the housing 22 of the emitter 20 designed to facilitate the same irrigation fluid path but a different accumulatable fluid path. The structure of the cover 23 is the same as that of the emitter 20, as is the irrigation fluid path from inlet nozzle 25 to emitter outlet 26.

Fig.10 shows the interior of the housing 60 between front surface of housing 60 and rear surface of housing 60. The housing 60 further comprises multiple openings 61 to the emitter's exterior, a round channel 64 and two orifices 65 connecting the round channel 64 to the fluid-accumulation chamber 63. The interior of the round channel 64, the orifices 65 and the fluid-accumulation chamber 63 house a moisture- absorbing material 62. The fluid- accumulation chamber 63 further houses a moisture- sensitive material 66 with the property of expanding when its moisture level increases and contracting when its moisture level decreases. The accumulatable fluid path of housing 60 is formed from the exterior of the emitter to the fluid-accumulation chamber 63 through the openings 61, the round channel 64 and the orifices 65. The irrigation flow path and accumulated-fluid path are arranged to prevent fluid communication of the orifices 65 with the emitter inlet 25.

When the moisture level at the exterior of the emitter increases, the moisture- absorbing material 62 transfers moisture from the exterior of the emitter to the moisture- sensitive material 66 via the accumulatable fluid path of the housing 60. In response to the rising moisture level, the moisture-sensitive material 66 expands, thereby accumulating fluid in the fluid-accumulation chamber 63 to a point where it transitions to its second state of blocking drip flow from the outlet 26.

When the moisture level at the exterior of the emitter decreases, the moisture- absorbing material 62 transfers moisture from the moisture- sensitive material 66 via the accumulatable fluid path of the housing 60 to the exterior of the emitter. In response to dropping moisture level, the moisture- sensitive material 66 contracts, thereby collapsing the fluid-accumulation chamber 63 to a point where it transients back to its first state of being free of accumulatable fluid and allowing drip flow from the emitter outlet 26.

It should be clear from the aforementioned operation of the housing 60 that there is a variety of materials that can be used as the moisture-absorbing material 62. For example, the moisture-absorbing material 62 may be a microfiber cloth supporting capillary action. One example of such cloth is a cleaning cloth of the kind produced by Starfiber®.

There is also a variety of materials that can be used as the moisture-sensitive material 66. For example, the moisture-sensitive material 66 may be a super absorbent polymer based on potassium polyacrylate.

Fig.11 illustrates a yet another embodiment of the presently disclosed subject matter in the form of an inline drip irrigation emitter 80 designed so that its fluid-accumulation chamber transitions to its second state only when a predetermined amount of irrigation fluid has been dispensed from its emitter outlet.

The drip irrigation emitter 80 is configured for being integrally attached to an interior surface of an irrigation pipe so as to provide fluid communication of the emitter inlets 86, 90 with an interior of the irrigation pipe and of the emitter outlet 84 with an exterior of the pipe.

Drip irrigation emitter 80 comprises a housing implemented using a first layer 82 and a second layer 83. Emitter 80 further comprises a cover 81. The first layer 82 is attached on top of second layer 83 to form a housing with open space 85 over which the cover 81 is placed. The second layer 83 is presented with the fluid-accumulation chamber 93 in its first state of being free of accumulatable fluid. Fig.12 shows the second-layer housing 83 with the fluid-accumulation chamber 93 in its second state of containing a predetermined amount of accumulatable fluid. The fluid-accumulation chamber 93 can be in the form of a diaphragm sealingly held in place by the first layer 82.

The functionality of drip irrigation emitter 80 is the same as that of the embodiment described using Figs. 4-8 but its irrigation fluid path and accumulatable fluid path are constructed differently.

The first part of the irrigation flow path is formed from the inlet 86 through the pressure-reducing labyrinth 87, the channel 88 and the inlet of the valve 89. The second part of the irrigation flow path is formed from the outlet of valve 89 to the emitter outlet 84 through the space 85. The accumulated-fiuid path is formed from the inlet 90 to the fluid- accumulation chamber 93 through the pressure reducing labyrinth 91 and the orifice 92. The irrigation flow path and accumulated-fluid path are arranged to prevent fluid communication of the orifice 92 with the emitter inlet 86.

Fig. 13 shows a yet another embodiment of the presently disclosed subject matter in the form of an integral drip irrigation emitter 100 with the fluid-accumulation chamber 107 in its first state of being free of accumulatable fluid. Emitter 100 is designed so that the fluid- accumulation chamber 107 transitions to its second state only when a predetermined level of moisture has been reached at the exterior of the emitter outlet 108.

The drip irrigation emitter 100 is configured for being integrally attached to an interior surface of an irrigation pipe so as to provide fluid communication of the emitter inlet 103 with an interior of the irrigation pipe and of the emitter outlet 108 with an exterior of the pipe.

The functionality of emitter 100 is the same as that of the yet another embodiment described using Fig. 9-10 but its irrigation fluid path and accumulatable fluid path are constructed differently.

Drip irrigation emitter 100 comprises a housing 102 and a cover 101. The cover 101 is placed over the housing 102 to form an open space on top of the fluid-accumulation chamber 107. Fig. 14 shows the housing 102 with the fluid-accumulation chamber 107 in its second state of being full.

The first part of the irrigation flow path is formed from the inlet 103 to the to the inlet of the valve 105 through the pressure -reducing labyrinth 104. The second part of the irrigation flow path is formed from the outlet of the valve 105 to the emitter outlet 108 through the space enclosed by cover 101 above the fluid-accumulation chamber 107. The accumulatable fluid path of the housing 102 is from the exterior of the emitter outlet 108 to the fluid- accumulation chamber 107 through the openings 109, the channel 106 and the orifice 110. The openings 109, the channel 106, the orifice 110 and the fluid-accumulation chamber 107 house a moisture-absorbing material. The fluid-accumulation chamber 107 further houses a moisture-sensitive material.

The embodiments described above were presented by way of non-limiting examples only, and the presently disclosed subject matter has features different from those described above.

For example, the amount of fluid in the fluid-accumulation chamber when in its first and second state can be other than zero and maximal possible, respectively. In other words, in the first state the chamber does not need to be completely empty of fluid but rather can have a minimal amount of fluid therein, and in the second state the amount of fluid does not need to be such as to completely block the emitter outlet. Accordingly, the emitter can be configured to provide the rate of drip flow through the emitter outlet that will gradually decrease as the fluid-accumulation chamber transitions from its first state of being free of accumulatable fluid or having its minimal amount and allowing drip flow through the emitter outlet, to its second state of containing a predetermined amount of accumulatable fluid which is less than that needed for preventing drip flow through the emitter outlet.

It should also be clear that the irrigation cycle described with reference to Fig. 3 may follow a different regime of applying pressurized fluid to fluid lines 54. For example, it is possible to introduce into the pipe pressurized fluid of relatively low pressure for a relatively long period of time instead of a relatively high pressure for a relatively short period of time.

In all the above examples of emitters, the fluid-accumulating chamber can be made in a variety of ways. For example, it can be made of an expandable fluid impermeable material such as an elastomer sealingly attached to the rear surface of the housing around its orifice.

It should further be clear that in all the above examples of emitters, the restriction of drip flow from the emitter outlet following the transition of the fluid-accumulation chamber to its second state may be implemented in a variety of ways. For example, the fluid- accumulation chamber can be configured to actuate a mediating mechanism such as a gate valve or ball valve. In another example, the fluid-accumulation chamber can push a flexible diaphragm membrane to block drip flow from the emitter outlet.

In all the above examples of emitters, the valve can be a slit valve, an umbrella valve or any other valve, configured to pass fluid therethrough from the pressure-reducing mechanism to the space leading to the emitter outlet as long as pressure differential between the valve's inlet and outlet is not lower than its predetermined operational pressure differential.

It should further be clear that any of the emitters described above can also be fitted with an anti-drain valve disposed immediately after the emitter inlet, to prevent the flow of fluid from entering the emitter when pressure at the emitter inlet drops below some predefined value. The anti-drain valve can also facilitate pressure regulating functions when implemented using a flexible diaphragm as is well known in the art. Examples of further such embodiments are presented in Figs. 15-16.

Thus, Fig.15 illustrates a housing 40 that can be used instead of the housing 22 in the online drip irrigation emitter 20 presented in Figs. 4-7.

The structure of the housing 40 is identical to that of the housing 22 except for the addition of an anti-drain valve 41 disposed downstream from inlet 25 and upstream to channel 30 (not shown). As known to those skilled in the art, the opening pressure and closing pressure of the anti-drain valve 41 can be set to prevent flow from entering the emitter when the pressure at the inlet 25 is below a predefined value. In the context of the presently disclosed subject matter, the opening pressure and closing pressure of the anti-drain valve 41 can be further set so that the difference between them corresponds to the predetermined operational pressure differential of valve 27, thereby ensuring that fluid does not flow through the accumulatable fluid path without also flowing through the entire irrigation fluid path.

Fig.16 illustrates a layer 73 that can be used instead of the layer 83 of the online drip irrigation emitter 80 presented in Fig. 11.

The structure of the layer 73 is identical to that of the layer 83 except for the addition of an anti-drain valve 94 disposed upstream to inlets 86 and 90 and an inlet 95 disposed upstream to anti-drain valve 94. The functionality of the anti-drain valve 94 is the same as the functionality of anti-drain valve 41 described for Fig. 15.

The valve 89 of the emitter 80 can be integral with the fluid-accumulating chamber 93 and, more particularly, they can constitute a single unitary component placed in the emitter 80. For example, the valve 89 and fluid-accumulating chamber 93 can be implemented on a single flexible diaphragm.

Furthermore, the valve 89, the fluid-accumulating chamber 93 and the anti-drain valve 94 can all be implemented on a single flexible diaphragm where all their three functions can be achieved using slits and variable thickness. More particularly, the diaphragm can be thicker and be non-expandable at the area of the valve 89 and the anti-drain valve 94, and be thinner and expandable at the area of the fluid-accumulating chamber 93.

One example of such diaphragm designated as 120 is shown in FIGS.17A to 18. Thus, in the top view of the diaphragm 120 shown in Fig. 17A, its upper surface is seen with the anti-drain slit valve inlet 124 and the slit valve inlet 125 as well as one side of the fiuid- accumulation chamber 126 while in its first state. In the bottom view of the diaphragm 120 shown in Fig. 17B, the diaphragm lower surface is seen with the anti-drain slit valve outlet 128 and the slit valve inlet 129, as well as the other side of the fluid-accumulation chamber 126 in its first state. Fig. 18 is a top view of the diaphragm 120 showing its upper surface when the fluid-accumulation chamber 126 is in its second state. Embodiments including diaphragm 120 would have their irrigation fluid path flow upstream to the anti-drain slit valve inlet 124 and downstream from the anti-drain slit valve outlet 128 and then upstream to the slit valve inlet 129 and downstream from the slit valve outlet 125.

Claims

CLAIMS:

1. A drip irrigation emitter comprising:

an emitter inlet, an emitter outlet, and an irrigation fluid path extending therebetween comprising:

o a pressure-reducing mechanism configured to convert fluid flow entering the emitter inlet under pressure, into a drip flow exiting the pressure- reducing mechanism, and

o a space, via which the drip flow has to pass in order to reach the emitter outlet; and

o a valve having a valve inlet downstream from the pressure-reducing mechanism and a valve outlet upstream to said space, and configured to allow the drip flow from the valve outlet into said space as long as fluid pressure differential between the valve inlet and the valve outlet is not less than an operational pressure differential; and

2. A drip irrigation emitter according to Claim 1, wherein said mechanism is a fluid- accumulation chamber configured for being brought into fluid communication with an exterior of the emitter for receiving therefrom at least indirectly an accumulatable fluid and further configured to allow introduction of the accumulatable fluid into the chamber to cause the chamber to change its state between a first state, in which the amount of said accumulatable fluid in the chamber is minimal and a second state, in which amount of the accumulatable fluid in the chamber is maximal and in which fluid communication between said space and the emitter outlet is prevented, causing the pressure differential at said valve to drop below the operational pressure differential.

3. A drip irrigation emitter according to Claim 2, wherein said space is configured to accommodate said chamber at least when in its second state.

4. A drip irrigation emitter according to Claim 2 or 3, wherein in the first state of the chamber, it is free of said accumulatable fluid.

5. A drip irrigation emitter according to any one of Claims 2, 3 and 4, wherein fluid communication of the fluid- accumulation chamber with the exterior of the emitter is provided along an accumulatable fluid path and, optionally, said chamber is configured for removal of the accumulatable fluid therefrom into the exterior of the emitter along the same accumulatable fluid path.

6. A drip irrigation emitter according to any one of Claims 2 to 5, wherein the maximal amount of the accumulatable fluid, which can be introduced in the chamber to bring it into said second state, is selected so as to ensure that this amount is reached only when a predetermined amount of irrigation fluid has been dispensed from the emitter outlet.

7. A drip irrigation emitter according to Claims 2 to 5, wherein the maximal amount of the accumulatable fluid, which can be introduced in the chamber to bring it into said second state, is selected so as to ensure that this amount is reached only when a predetermined level of moisture has been reached at the exterior of the emitter outlet.

8. A drip irrigation emitter according to Claims 2 to 6, further comprising a housing having a housing front surface and a housing rear surface, the housing front surface being formed with said emitter inlet and the housing rear surface being formed with said valve with said pressure-reducing mechanism therebetween.

9. A drip irrigation emitter according to Claim 8, further comprising a cover formed with said emitter outlet, the cover being so assembled with the housing as to form said space between the valve outlet and the emitter outlet.

10. A drip irrigation emitter according to Claim 5 or any one of Claims 6 to 9, when dependent on Claim 5, wherein said accumulatable fluid path comprises a pressure- reducing mechanism.

11. A drip irrigation emitter according to Claim 10, wherein the pressure-reducing mechanisms of the accumulatable fluid path and the irrigation fluid path are not identical.

12. A drip irrigation emitter according to Claim 5 and any one of Claims 6 to 11 when dependent on Claim 5, wherein the accumulatable fluid path provides fluid communication between the chamber and the emitter inlet, so as to allow fluid entering the emitter via said emitter inlet to simultaneously flow along the irrigation fluid path and along the accumulatable fluid path.

13. A drip irrigation emitter according to any one of Claims 2 to 11, wherein said chamber has an interior filled with a moisture-sensitive material, and is in fluid communication with an exterior of the emitter at least at one location thereof other than the emitter inlet such as to prevent fluid communication of the chamber with the emitter inlet.

14. A drip irrigation emitter comprising:

a fluid-accumulation chamber in fluid communication with the emitter inlet to cause fluid entering the emitter via said emitter inlet to simultaneously flow along the irrigation fluid path and into said chamber, the chamber being configured to change its state between a first state, in which the amount of said accumulatable fluid in the chamber is minimal and a second state, in which amount of the accumulatable fluid in the chamber is maximal and in which fluid communication between said space and the emitter outlet is prevented, causing the pressure differential at said valve to drop below the operational pressure differential.

15. A drip irrigation emitter according to any one of the preceding claims, configured for being mounted onto an exterior surface of an irrigation pipe so as to provide fluid communication of the emitter inlet with an interior of the irrigation pipe.

16. A drip irrigation emitter according to any one of Claims 1 to 14, configured for being integrally attached to an interior surface of an irrigation pipe so as to provide fluid communication of the emitter inlet with an interior of the irrigation pipe and of the emitter outlet with an exterior of the pipe.

17. A drip irrigation emitter according to any one of the preceding claims, further comprising an anti-drain valve disposed downstream from its inlet.

18. A drip irrigation emitter according to any one of Claims 2-17, where its valve and fluid- accumulation chamber are implemented on a single flexible diaphragm.

19. A drip irrigation emitter according to Claim 17, where its valve, anti-drain valve and fluid-accumulation chamber are implemented on a single flexible diaphragm.

20. A method of producing a drip irrigation emitter according to any one of the preceding claims, comprising providing the emitter with said mechanism and said valve configured to allow the drip flow from the valve outlet into said space as long as fluid pressure differential between the valve inlet and the valve outlet is not less than an operational pressure differential.

21. An irrigation pipe comprising a plurality of drip irrigation emitters of the kind defined in any one of Claims 1 to 19, disposed at different distances from a location, at which the pipe is configured to receive therein pressurized irrigation fluid.

22. An irrigation pipe according to Claim 20, operable at least at one fluid pressure at said location so that, once said chamber is in its second state in at least one of the drip emitters, at least some of the remaining drip emitters will experience an increased pressure of fluid at their inlets.

23. An irrigation pipe comprising a plurality of drip irrigation emitters disposed at different distances from a location, at which the pipe is configured to receive therein pressurized irrigation fluid, each emitter comprising:

o a pressure-reducing mechanism configured to convert fluid flow entering the emitter inlet under pressure into a drip flow from the outlet, o a space, via which the drip flow has to pass in order to reach the emitter outlet; and

a mechanism configured to change a state of the fluid irrigation path between a first, operational state allowing said drip flow through said valve and said space towards the outlet, and a second state in which fluid communication is prevented between said space and the emitter outlet, so that at least at one fluid pressure at said location, at least once the state of the irrigation fluid path reaches its second state in at least one of the drip emitters, at least some of the remaining drip emitters will experience an increased pressure of fluid at their inlets.