AU2001293496B2

AU2001293496B2 - Automatic irrigation system and control device therefor

Info

Publication number: AU2001293496B2
Application number: AU2001293496A
Authority: AU
Inventors: Frederick John Zass
Original assignee: Individual
Current assignee: Zass Frederick
Priority date: 2000-09-28
Filing date: 2001-09-28
Publication date: 2007-12-20
Anticipated expiration: 2021-09-28

Description

05/12/2007 16:30 05/2/001830freehilIs 12345878 4/7 005063643 c~Kl AUTOMATIC IRRIGATION SYSTEM AND CONTROL DEVICE TH-EREFOR This invention relates to irrigation systems, and more particularly to a system and device for automatically controlling the supply of irrigation water in accordance with the moisture 0 content of the soil to be irrigated.

5 Automatic irrigation systems have previously been proposed in which the system is programmed to operate at particular times. Such systems may also include devices, such as probes inserted into the soil, for monitoring the moisture content of the soil so that the system does not operate when the moisture content exceeds a predetermined value. However, such o automatically controlled irrigation systems can be complex and expensive to manufacture, install S 10 and maintain.

Another disadvantage of prior irrigation systems is that the controls are usually located above ground, and are susceptible to damage, e. g by vandalism, when the system is installed in public places such as public parks or gardens.

It is therefore desirable to provide a simple, yet effective, device for automatically controlling the supply of irrigation water according to the moisture content of the soil.

It is also desirable to provide an automatic control for an irrigation system which is readily inexpensive and which is not susceptible to damage.

According to one aspect of the invention, there is provided an irrigation control device comprising a receptacle for water adapted to be buried in soil underground, the receptacle having an upper part with perforated sides for receiving water from the soil underground and a lower part without perforations for collecting water; and an electrical switch means adapted to be connected electrically to a flow control valve of an irrigation system to control operation of the flow control valve in accordance with the level of water collected in the lower part of the receptacle, the switch means having a state indicative of the water collected in the receptacle being above a predetermined upper level and a state indicative of the water being below a predetermined lower level, wherein the switch means causes the flow control valve to be closed when the water collected in the receptacle rises above the predetermined upper level, and wherein the switch means causes the flow control valve to open when the water collected in the receptacle falls below the predetermined lower level.

COMS ID No: ARCS-171303 Received by IP Australia: Time 16:32 Date 2007-12-05 05/12/2007 10:06 05/2/20710:5 reehllls 12345878 7/11 o -2o The water level in the receptacle depends upon the moisture content of the surrounding soil, which in turn is dependent upon factors such as weather conditions, irrigation and plant transpiration. The switch means is adapted to open the flow control valve so that irrigation water is supplied to the soil when ON the water collected in the receptacle falls below the predetermined lower level.

o The receptacle will then collect water from the soil as inrigation (or rain) takes Cl place, causing the water level in the receptacle to rise. The switch means is then adapted to close the flow control valve to turn off the supply of irrigation water when the water in the receptacle rises above a predetermined upper level.

Preferably, the upper part of the receptacle has a plurality of vertically and horizontally spaced holes, and in a particularly preferred embodiment the predetermined upper level corresponds approximately to the lowest level of holes in the receptacle.

The switch means is preferably a float-operated switch which comprises a float body and a tilt switch mounted on or within the float body. The float body may be mounted for pivotal movement on a side wall of the receptacle, so that when the float body pivots between a first position corresponding to the predetermined upper level and a second position corresponding to the predetermined lower level, the tilt switch opens or closes to control the operation of the flow control valve.

According to another aspect of the invention, there is provided an automatically controlled irrigation system comprising: an irrigation system control device in accordance with the first aspect of the invention; and a flow control valve having an inlet connected to a water supply, at least one outlet connected to one or more irrigation pipes, and an electrically-operated valve member adapted to control the passage of water from the water supply through the flow control valve to the irrigation pipes, wherein the flow control valve is connected to the irrigation system control device in such a manner that the COMS ID No: ARCS-171199 Received by IP Australia: Time 10:08 Date 2007-12-05 PCT/AU01/01219 Received 22 August 2002 -2aswitch means of the control device controls operation of the electricallyoperated valve member in accordance with the level of water in the receptacle of the control device, the switch means being adapted to move the electrically operated valve member into a closed position when the water collected in the receptacle rises above a predetermined upper level, and the switch means is adapted to move the electrically-operated valve member into an open position when the level of water collected in the receptacle falls below a predetermined lower level.

/a&JaEmDo SHEE

IPI-VAU

WO 02/26027 PCT/AU01/01219 -3- Such an automatically controlled irrigation system does not require a programmed timer to operate at programmed times, and is operated solely by the level of water in the receptacle which is dependent upon the actual moisture of the soil surrounding the receptacle. This is in turn dependent upon weather conditions and plant transpiration.

In such a system, it is desirable to prevent the direct ingress of rain water from above the receptacle, and for this purpose a closed lid is preferably provided for the rcccptaclc.

A preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic diagram of an automatic irrigation system in accordance with the invention; Figure 2 is a section on the line 2-2 of Figure 1 through an irrigation control device of the system installed underground; Figure 3 is a section on the line 3-3 of Figure 2; and Figure 4 is an exploded perspective view of the components of the device of Figure 2.

The irrigation system illustrated schematically in Figure 1 comprises a flow control valve 10 and an irrigation system control device 20. The flow control valve has an inlet 12 connected to a water supply 14 by a supply pipe 15, at least one outlet 16 connected to an irrigation pipe 17, and a solenoid-operated valve member 18 which is moveable between a closed position in which it shuts-off a passage between the inlet 12 and the outlet 17, and an open position in which it allows the water to flow from the inlet 12 connected to the water supply to the irrigation pipe 17. The flow control valve 10 of Figure 1 is shown having a plurality of outlets 16 each connected to a respective irrigation pipe 17, although it will be appreciated that a flow control valve having only a single outlet may be provided.

An electrical power supply 30 is connected by an electrical wire 31 to a solenoid 19 of the flow control valve 10 and by another electrical wire 32 to the irrigation control device 20 which is also connected electrically by a further electrical WO 02/26027 PCT/AU01/01219 -4wire 33 to the solenoid 19.

Referring more particularly to Figures 2 to 4, the irrigation control device comprises a perforated receptacle 21 for water and a float-operated electrical switch The perforated receptacle 21 has a base 22, a cylindrical side wall 23 and a closed lid 24. The side wall 23 has a perforated upper part 26 provided with a plurality of vertically and horizontally spaced holes 27, and a lower imperforate part 28 which is adapted to collect moisture and water passing through the holes 27 from the soil surrounding the receptacle 21.

The receptacle is preferably made from a synthetic plastics material, such as PVC, although it will be appreciated that it may be made from any other convenient material provided it has a perforate upper part and an impervious lower part 28.

The float-operated electrical switch 40 comprises a mounting plate 42 mounted to the inner surface of the cylindrical wall 23 of the receptacle, e.g by one or more mounting bolts (not shown) extending through one or more the holes 27, a pair of side limbs 44 extending from the each side of the mounting plate 42 into the receptacle, and a float member in the form of a cylindrical body 46 pivotally mounted on a shaft extending between the side limbs 44. The body 46 of the float member is preferably made from a light plastics material and a tilt switch 48 is mounted on or within the body 46. The tilt switch 48 is electrically connected by wires 32 and 33 to the electrical power supply 30 and to the solenoid 19 of the flow control valve respectively. The tilt switch 48 may be a commercially available mercury tilt switch.

The electrical power supply is preferably a mains power supply, although an electrical battery could be used instead.

The irrigation control device 20 may also include an outer protection tube The protection tube 50 as shown in Figures 2 to 4 has open upper and lower ends 51, 52 and a perforated side wall 53 having apertures 54 extending throughout the height of the side wall 53 to allow moisture to pass from the soil outside the protective tube into the space surrounding the inner perforated receptacle 21.

In use, as shown in Figures 2 and 3, the irrigation control device 20 is buried in WO 02/26027 PCT/AU01/01219 soil 60 underground. The space between the irrigation control device 20 and the outer protective tube 50 may be filled with soil, or it may be filled with a more pervious material, such as small stones or pebbles 61, so that the passage of moisture and water from the soil 60 into the receptacle 21 is not impeded.

The irrigation control device 20 is connected to the electrical power supply and to the solenoid-operated flow control valve 10 of the irrigation system described with reference to the schematic diagram in Figure 1.

The float-operated electrical switch 40 of the irrigation control device 20 is arranged to control the operation of the flow control valve in the following manner.

The receptacle 21 of the control device 20 collects moisture and water from the soil as rain or irrigation is taking place. The water rises in the receptacle and this causes the pivotally mounted float body 46 to rise. When the water level has reached a predetermined upper level which preferably corresponds approximately to the lowest level of holes 27 in the receptacle 21, the tilt switch 48 operates to close the solenoidoperated control valve 10 so that the supply of irrigation water to the irrigation pipes 17 is shut off by the flow control valve 10. The solenoid-operated flow control valve is turned off prior to field capacity, and thereafter no more irrigation takes place until warmer and drier weather conditions and/or plant transpiration causing moisture to evaporate from the soil and from the lower part of the receptacle results in the level of water within the receptacle falling to a predetermined lower level 70 as illustrated in Figure 2. When the water collected in the receptacle falls below the predetermined lower level 70, the tilt switch 48 of the float-operated switch 40 is adapted to open the flow control valve 10 so that irrigation water is supplied through the flow control valve from the water supply 14 to the irrigation pipes 17.

When the water level in the receptacle 21 has again risen to the predetermined upper level indicated by broken line 71 in Figure 2, the tilt switch 48 again activates the solenoid-operated flow control valve 10 to turn off the supply of water to the irrigation pipes 17.

Preferably, the predetermined upper and lower levels are factory set so that the lower level corresponds to a moisture content of the soil prior to the plant wilting point, and the predetermined upper level corresponds to just prior to field capacity for PCT/AU01/01219 Received 22 August 2002 -6the irrigation system. In a particularly preferred embodiment, the predetermined lower level is from 4 to 10 millimetres below the predetermined upper level, and more preferably approximately 6 millimetres below the predetermined upper level.

It will be appreciated from the description above that the present invention provides a relatively simple and inexpensive irrigation system control device which can be used in an automatic irrigation system which does not require any complicated timing or programming system to control the flow control valve. The location of the irrigation system control device in a buried position underground is advantageous in several respects. The control device is able to control the irrigation system solely in accordance with the moisture content of the soil surrounding the irrigation control device. Also, because it is buried underground, it is less susceptible to damage from vandalism etc. as opposed to irrigation control boxes located above the ground.

It will also be appreciated that various modifications may be made to the preferred embodiments described above without departing from the scope and spirit of the present invention. For example, the shape and dimension of the receptacle of the control device may be varied for different applications, and whilst a mercury tilt switch is used in the preferred embodiment, the switch means may take a variety of different forms.

AMENDED SHEET IpEANJ

Claims

2. A control device according to claim I wherein the upper part of the receptacle has a plurality of vertically and horizontally spaced holes, and the level of the water collected in the lower part, of the receptacle is dependent upon water and moisture passing from the soil surrounding the receptacle through the holes into the receptacle.
3. An irrigation control device according to claim 2 wherein the level of the water collected in the lower part of the receptacle is dependent upon moisture passing through the holes from the receptacle into the soil owing to plant transpiration.
4. A control device according to claim 2 or claim 3 wherein the predetermined upper level corresponds approximately to the lowest level of holes in the receptacle. A control device according to any one of the preceding claims wherein switch means comprises a float-operated switch having a float body and a tilt switch mounted on or within the float body.
6. A control device according to claim 5 when the float body is mounted for pivotal movement on a side wall of the receptacle. COMS ID No: ARCS-171303 Received by IP Australia: Time 16:32 Date 2007-12-05 WO 02/26027 PCT/AU01/01219 -11-
7. A control device according to claim 6 wherein the float body is pivotally mounted on a shaft extending between limbs projecting into the receptacle from a mounting plate on a side wall of the receptacle.
8. A control device according to any one of the preceding claims wherein the receptacle has a closed lid for preventing the ingress of rain water from above the receptacle.
9. An irrigation system control device according to any one of the preceding claims wherein an outer protective perforated tube is provided around the receptacle.
10. An automatically controlled irrigation system comprising: an irrigation system control device in accordance with any one of the preceding claims; and a flow control valve having an inlet connected to a water supply, at least one outlet connected to one or more irrigation pipes, and an electrically- operated valve member adapted to control the passage of water from the water supply through the flow control valve to the irrigation pipes; wherein the flow control valve is connected to the irrigation system control device in such a manner that the switch means controls operation of the electrically-operated valve member in accordance with the level of water in the receptacle of the control device, the switch means being adapted to move the electrically-operated valve member into a closed position when the water collected in the receptacle rises above a predetermined upper level, and the switch means being adapted to move the electrically-operated valve member into an open position when the water collected in the receptacle falls below a predetermined lower level.
11. An irrigation system according to claim 10 wherein the level of water collected in the receptacle is dependent upon water and moisture passing from the soil surrounding the receptacle through a perforated side wall of the upper part of the receptacle. AMENDED SHEET (ARTICLE 19) s~ PCT/AU01/01219 Received 22 August 2002 -9-
12. An irrigation system according to claim 11 wherein the level of the water collected in the receptacle is dependent upon moisture passing through the holes from the receptacle into the soil owing to plant transpiration.
13. An irrigation system according to any one of claims 10 to 12 wherein movement of the electrically-operated valve member is controlled by a solenoid connected to the switch means of the control device.
14. An irrigation system according to any one of claims 10 to 13 wherein the receptacle of the control device has a closed lid for preventing the ingress of rain water from above the receptacle.
15. An irrigation system according to any one of claims 10 to 13 wherein the switch means comprises a float-operated switch. AmIraA'D sll 1pe%4AVd