GB2334071A

GB2334071A - Apparatus for the distribution of a liquid under pressure

Info

Publication number: GB2334071A
Application number: GB9718532A
Authority: GB
Inventors: David Alfred Lucas
Original assignee: LONG REACH IRRIGATION Ltd
Current assignee: LONG REACH IRRIGATION Ltd
Priority date: 1997-09-01
Filing date: 1997-09-01
Publication date: 1999-08-11
Anticipated expiration: 2017-09-01
Also published as: GB2334071B; GB9718532D0

Abstract

An apparatus for the distribution of a liquid under pressure comprises a reservoir 2 having an inlet 3 and an outlet 7 and means for filling liquid into the reservoir 2 via the inlet 3. The outlet 7 includes an outlet valve 9 switchable between an open position in which liquid is able to pass from the reservoir 2 through the outlet 7 and a closed position in which the liquid is prevented from passing through the outlet 7. The apparatus further includes a pressure means for detecting the pressure in the apparatus and signal generating means for generating an electrical signal when the pressure in the apparatus is at a predetermined value. The electrical signal causes the outlet valve 9 to switch between the open and closed positions. The apparatus is particularly suitable for distributing water in high pressure bursts over a large area, for example a sports field.

Description

Apparatus for the Distribution of a Liquid The present invention relates to apparatus for the distribution of a liquid. In particular, the invention relates to irrigation apparatus for the distribution of water.

A problem with many irrigation systems is the provision of liquid at a sufficient pressure that a long "throw" of the liquid is obtained, that is the liquid travels for a long distance from the device before reaching the ground. By increasing the throw of the liquid the number of irrigation devices required for a given area to be irrigated is reduced. Where the liquid to be distributed is water, water is often used directly from the mains supply and often the pressure of the mains water is not sufficient to provide the desired throw of water. It is therefore desirable to provide means in the irrigation apparatus for pressurising the liquid.

That is especially important where the area to which the liquid is to be supplied is large, for example a sports field. If the liquid could be pressurised sufficiently for the liquid from the device to reach further than halfway across the area, it would be necessary to provide irrigation apparatus only outside the boundary of the area and thus it would be possible to provide fixed irrigation apparatus rather than relying on portable apparatus to distribute liquid to the centre of the area.

Devices are generally known for pressurising water in a vessel for supplying water to, for example, domestic or industrial water supplies. In one such type of device, water is pumped from, for example, the mains water supply into a bladder which is confined within a pressure tank. As the water is pumped into the bladder, the bladder expands thereby pressurising the air in the tank around the bladder and increasing the pressure in the tank. When sufficient water has been pumped into the bladder for the pressure in the tank to reach a certain predetermined pressure, the pump is stopped. The pressurised water may then be drawn off under pressure as required, for example from a tap. When the pressure in the pressure tank falls below a certain level as the water is drawn off, the pump is turned on and more water is pumped into the bladder.

British Patent Application No. 2 263 421 describes a liquid delivery apparatus for irrigating farm land.

The apparatus uses a bladder device to pressurise water before it is released and sprayed onto the land. In the devices described in GB 2 263 421, water is pumped into a bladder which is contained in a pressure tank. As the bladder expands with the addition of the liquid, the air between the bladder and the walls of the pressure tank is compressed. A pipe is provided between the tank and a valve device and when the pressure of the air in the tank exceeds a predetermined amount, a valve opens allowing liquid in the bladder to escape via an outlet pipe.

The arrangements described in GB 2 263 421 are complex mechanical arrangements. Furthermore, the pressure at which the liquid is released from the bladder is determined by several different factors and the selection of the pressure at which the valve is opened and is closed, and thus the pressure at which the liquid is released, is difficult. Moreover, in the apparatus described, the outlet from the bladder to the outlet pipe is partially obstructed by the mechanical closure mechanism so that the liquid leaving the bladder is impeded and the speed that the bladder is emptied is reduced to some extent.

It is an object of the invention to provide an apparatus which overcomes or mitigates the abovementioned disadvantages.

According to the invention there is provided apparatus for the distribution of a liquid under pressure, the apparatus comprising a reservoir having an inlet and an outlet, means for filling liquid into the reservoir via the inlet, the outlet including an outlet valve switchable between an open position in which liquid is able to pass from the reservoir through the outlet and a closed position in which the liquid is prevented from passing through the outlet, the apparatus further including a pressure means for detecting the pressure in the apparatus and signal generating means for generating an electrical signal when the pressure in the apparatus is at a predetermined value, the electrical signal causing the outlet valve to switch between the open and closed positions.

As liquid is fed into the reservoir, the pressure in the apparatus increases. Thus liquid is stored under pressure in the reservoir. When the pressure in the apparatus reaches a first predetermined level as liquid is filled into the reservoir via the inlet, the pressure means causes an electrical signal which effects the opening of the outlet valve and the liquid is released in large volumes at high pressure. In the apparatus of the present invention, the outlet valve is opened by electricity and thus the outlet valve opens very quickly allowing the fast release of liquid from the reservoir.

As the liquid is released from the reservoir, the pressure in the apparatus will fall and when it reaches a second predetermined level, the pressure means causes the signal generating means to terminate the electrical signal which causes the outlet valve to close. The pressure in the system will then build up again as more liquid is filled into the reservoir.

In an advantageous embodiment of the invention, the arrangement is such that, in use, the outlet valve is closed before all pressure in the system is lost and preferably there is only a small loss in pressure before the outlet valve is closed. Thus the apparatus of the present invention can be used to produce bursts of liquid at high pressure. By using electricity to open the valve, the predetermined pressures at which the outlet valve is opened and the liquid is released and at which the outlet valve is closed are easily set and it is possible to avoid the use of complex mechanical arrangements to control the release of the liquid.

It is possible to produce an apparatus in accordance with the invention using only readily available components. That is clearly most advantageous.

Advantageously, the apparatus further includes a pressure tank, the reservoir being arranged in the pressure tank. Advantageously, the reservoir comprises a flexible bladder. As indicated above, such arrangements are known in the prior art to allow water to be stored at high pressure before being released.

Advantageously, the pressure tank is a closed vessel. In such an arrangement, where a bladder device is used for the reservoir, as liquid is filled into the bladder, the bladder expands and air (or other fluid) between the bladder and the wall of the pressure tank is compressed.

In some applications, where the liquid is water, the water may be filled into the reservoir from the mains supply. Advantageously, however, the apparatus further includes a pump for pumping liquid into the inlet of the reservoir.

Advantageously, the inlet includes a non-return inlet valve, the valve preventing the passage of liquid from the reservoir back through the inlet.

Advantageously, the pressure means includes a pressure switch. When the pressure in the apparatus reaches a certain predetermined level, the pressure switch generates an electrical signal which opens the outlet valve.

In most cases, the arrangement will be such that the outlet valve tends to the closed position, the electrical signal causing the valve to open. It is envisaged, however, that the outlet valve may be open in the absence of the electrical signal, the signal causing the valve to close while the liquid is filled into the reservoir and the signal being stopped at a predetermined pressure, such that the outlet valve opens. Further, the arrangement might be such that one signal is generated to open the outlet valve and a second, separate signal is generated to close the outlet valve at the predetermined pressures.

Advantageously, the pressure means detects the pressure of the liquid. Thus direct control of the pressure at which the liquid leaves the outlet is possible. Preferably, the pressure means detects the pressure of the liquid in the region of the outlet valve.

The apparatus may be installed in the area to which the liquid is to be delivered, or the apparatus may be mobile.

According to the invention, there is further provided a method of distributing a liquid under pressure, the method comprising filling liquid into a reservoir of a liquid distribution apparatus, the reservoir having an inlet and an outlet, the outlet having an outlet valve an outlet valve switchable between an open position in which liquid is able to pass from the reservoir through the outlet and a closed position in which the liquid is prevented from passing through the outlet, the apparatus further including a pressure means for detecting the pressure in the apparatus and signal generating means for generating an electrical signal when the pressure in the apparatus is at a predetermined value, the electrical signal causing the outlet valve to switch between the open and closed positions.

Where the apparatus further includes a pump for pumping liquid into the inlet of the reservoir, the pumping of the liquid into the inlet of the reservoir is preferably continuous.

The apparatus is advantageously used for irrigation in which case the liquid will usually be water, but it will be appreciated that the apparatus has further applications in which case the liquid may not be water.

For example, the liquid may be liquid fertilizer.

Embodiments of the invention will now be described having reference to the accompanying drawings of which: Figure 1 shows a schematic diagram of an irrigation apparatus according to the invention.

The irrigation apparatus shown in Figure 1 includes a pressure tank 1 comprising a rigid material, for example metal. Inside the pressure tank is arranged a bladder for storing water under pressure. A water inlet pipe 3 is arranged to deliver water to the bladder via an inlet valve 4 which is a non-return valve which allows water to pass from the inlet pipe 3 into the bladder 2 put prevents the back flow of water from the bladder back down the inlet pipe 3. A pump (not shown) may be connected to the inlet pipe 3. The bladder 2 may comprise flexible rubber material which is extensible such that the bladder expands within the pressure tank 1 when water is pumped into the bladder 2 under pressure via the water inlet pipe 3. As water is pumped into the bladder cavity 5 under pressure, the pressure in the bladder 2 increases and the bladder 2 expands, reducing the size of the air space 6 between the bladder 2 and the pressure tank 1.

An outlet pipe 7 is also in communication with the bladder 2 and the end of the outlet pipe 7 remote from the bladder 2 is connected to a nozzle 8 from which water is discharged from the outlet pipe 7. The outlet pipe 7 includes an outlet valve 9 which, when closed, prevents water passing from the bladder 2 through the outlet pipe 7 to the nozzle 8.

Associated with the neck of the bladder 2 is a pressure switch 10. The pressure switch is electrically connected to the outlet valve 9 and electrical signals from the pressure switch, in use, open the outlet valve.

The operation of the irrigation apparatus is as follows. The outlet valve 9 is initially closed and water is pumped into the bladder 2 via the water inlet pipe 3. The bladder 2 expands as the water is pumped into the bladder and the pressure in the pressure tank 1 increases as the air in the air space 6 reduces. When the pressure of the water in the bladder 2 reaches a certain predetermined level, the pressure switch 10 is activated and sends an electrical signal to the outlet valve 9 which opens allowing the pressurised water in the bladder 2 to escape from the pressure tank 1 via the outlet pipe 7. The pressure at which the pressure switch 10 is actuated can be chosen such that a powerful jet of water is ejected from the nozzle and the water jet from the nozzle extends a long distance across the area to be watered.

As water is ejected from the nozzle 8, the pressure in the bladder 2 decreases and at a predetermined pressure, the pressure switch 10 causes the electrical signal to cease and the outlet valve closes and prevents further water being expelled from the outlet pipe 7.

The cycle then repeats as water is again pumped into the bladder 2 via the inlet pipe 3.

In a preferred embodiment of the invention, water is continuously fed into the bladder via the inlet pipe.

Preferably, however, a safety cut-out is provided such that the pump stops if the pressure in the apparatus reaches a critical level.

The nozzle 8 may take one of several forms depending on the type of area the water is to be supplied to. For example, the nozzle may simply take the form of a pipe, in which case a high pressure jet of water may be ejected from the apparatus. In a different embodiment, the nozzle includes a sprinkler head so that a shower of water droplets is produced. Other nozzles are arranged so that their orientation changes while the water is ejected from the nozzle and/or between ejections of water. Such nozzles are known in the prior art and those or other nozzles may be used to produce the desired water jet from the apparatus.

In one alternative embodiment of the invention, the apparatus is installed in a fixed location in the area to which the water is to be supplied. For example, in one embodiment of the invention, the apparatus is used to provide water to a field. The apparatus is installed in the field and the outlet pipe is connected to a network of underground pipes feeding a number of sprinklers in sequence.

In an alternative embodiment of the invention, the apparatus is provided as a mobile device and may be, for example, installed on a carriage. The water source for such a device may be the mains supply and/or a water pump.

The apparatus is described above in relation to the distribution of water, but it will be appreciated that other liquids may be distributed by the apparatus, for example liquid fertilizer. It will be understood, unless it is clear to the contrary, that the references to water above include references to other liquids which may be distributed using the apparatus in accordance with the present invention.

Claims

Claims: 1. Apparatus for the distribution of a liquid under pressure, the apparatus comprising a reservoir having an inlet and an outlet, means for filling liquid into the reservoir via the inlet, the outlet including an outlet valve switchable between an open position in which liquid is able to pass from the reservoir through the outlet and a closed position in which the liquid is prevented from passing through the outlet, the apparatus further including a pressure means for detecting the pressure in the apparatus and signal generating means for generating an electrical signal when the pressure in the apparatus is at a predetermined value, the electrical signal causing the outlet valve to switch between the open and closed positions.
2. An apparatus according to claim 1, wherein the apparatus further includes a pressure tank, the reservoir being arranged in the pressure tank.
3. An apparatus according to claim 2, wherein the pressure tank is a closed vessel.
4. An apparatus according to any of claims 1 to 3, wherein the reservoir comprises a flexible bladder.
5. An apparatus according to any of claims 1 to 4, wherein the apparatus further includes a pump for pumping liquid into the inlet of the reservoir.
6. An apparatus according to any of claims 1 to 5, wherein the inlet includes a non-return inlet valve, the valve preventing the passage of liquid from the reservoir through the inlet.
7. An apparatus according to any of claims 1 to 6, wherein the pressure means includes a pressure switch.
8. An apparatus according to any of claims 1 to 7, wherein the pressure means detects the pressure of the liquid.
9. An apparatus according to claim 8, wherein the pressure means detects the pressure of the liquid in the region of the outlet valve.
10. An apparatus according to any of claims 1 to 9, wherein the apparatus is mobile.
11. An apparatus for delivering a liquid under pressure, the apparatus being substantially as herein described having reference to Figure 1 of the drawings.
12. A method of delivering a liquid under pressure, the method comprising filling liquid into a reservoir of a liquid delivery apparatus, the reservoir having an inlet and an outlet, the outlet having an outlet valve an outlet valve switchable between an open position in which liquid is able to pass from the reservoir through the outlet and a closed position in which the liquid is prevented from passing through the outlet, the apparatus further including a pressure means for detecting the pressure in the apparatus and signal generating means for generating an electrical signal when the pressure in the apparatus is at a predetermined value, the electrical signal causing the outlet valve to switch between the open and closed positions.
13. A method according to claim 12, wherein the apparatus further includes a pump for pumping liquid into the inlet of the reservoir, the pumping of the liquid into the inlet of the reservoir being continuous.
14. A method of delivering a liquid under pressure, the method being substantially as herein described having reference to Figure 1 of the drawings.