WO2004064498A1

WO2004064498A1 - Sprinkler system

Info

Publication number: WO2004064498A1
Application number: PCT/IL2003/001114
Authority: WO
Inventors: Kobi David
Original assignee: Kobi David
Priority date: 2003-01-21
Filing date: 2003-12-30
Publication date: 2004-08-05
Also published as: AU2003290391A1; IL154067A0

Abstract

The present invention relates to sprinkler systems for efficiently irrigating lawns, gardens or other areas of any shape. The disclosed sprinkler system includes a device disposed in a water supply line upstream of a standard rotary sprinkler, capable of automatically adjusting the velocity of the water supplied to the sprinkler, thereby controlling a spray distance and irrigation area of the sprinkler. The system also includes means for controlling the device according to data of an area to be watered, for spraying the area substantially in conformity with the boundaries of the area.

Description

S P R I N K L E R S Y S T E M

FIELD OF THE INVENTION

The present invention relates to sprinkler systems for efficient irrigation of areas of various shapes and, more particularly, to kits that may be retrofitted to existing irrigation sprinkler systems to enable them to irrigate more efficiently.

BACKGROUND OF THE INVENTION

Sprinkler systems for watering lawns and trees have long been known and generally include a valve such as a faucet, and a sprinkler coupled to a water line. Such sprinklers include, for example, rotating sprinklers and central sprinkler heads capable of irrigating a circular area or a limited circular section.

Sprinklers which are used in these systems often include a hammer- type mechanism, or another manual or mechanical mechanism for automatically rotating the spout of the sprinkler by utilizing the water pressure, to project water in a desired direction, such as those shown in US Patent 691,419 to Vandervoort and US Patent 5,372,306 to Yianilos. Other systems known in the art have automatic controllers, which fully open and close valves according to a pre-selected schedule.

Various conventional computerized sprinkler systems are shown, for example, in US Patents 4,209,131 to Barash et al., 5,021,939 to Pulgiese, 5,602,728 to Madden et al., and 6,098,898 to Storch.

A major disadvantage of such systems is that they are unable to water efficiently areas of different shapes, but rather require extensive overlapping of irrigation in order to fully water the desired area, or irrigate beyond the borders of the area to be watered, or leave edges or corners unwatered, thus causing water to be wasted or leaving flora without irrigation. In addition, such systems often require a relatively large number of sprinklers in order to cover the entire area. In practice, the water supply valves in conventional irrigation systems are computer controlled for fully open or fully closed operation to selectably permit or prevent the flow of water.

Various solutions to this problem have been sought, some of which utilize the principle that changing the pressure of a flow of water will change the distance from the water outlet that the water flow can reach.

Thus, by increasing the pressure, a jet of water may extend to a greater distance from the outlet.

Prior art patents utilized this principle by designing new and complex sprinkler heads, which include therein complicated mechanisms for changing the angle of the sprinkler spout, or for changing the water pressure or flow rate inside the sprinkler.

US Patent 4,613,077 to Aronson describes a mechanically programmable sprinkler having a sprinkler body and a rotatable head assembly with a laterally directed nozzle for directing a stream of fluid to cover a selected area around the sprinkler. A variable flow control valve consists of a slide mounted in the head of the sprinkler for controlling the flow of fluid to the nozzle. A mechanically programmed cam is mounted on the body of the sprinkler, and a cam follower, mounted on the valve slide, follows the cam to vary the valve opening in relation to the rotational position of the head relative to the body. The valve controls the volume and throw of the fluid stream so that the sprinkler covers uniformly an area of irregular noncircular configuration.

US Patent 4,819,875 to Beal describes a contour control device for use with rotary irrigation sprinklers. The device includes a housing, within which is disposed a throttling means comprising a flexible, resilient band, and a plurality of adjustment pins which cooperate with a rotating inlet to the sprinkler to throttle the volume of water flow to the sprinkler in accordance with the rotary position of the sprinkler relative to the housing. US Patent 5,248,093 to Pleasants describes an automatic robotic lawn sprinkler including a manually programmable base assembly for anchoring to the ground and containing site specific range data, an azimuth rotor assembly rotatably mounted to the base in a horizontal plane, a range rotor assembly rotatably mounted in a vertical plane substantially perpendicular to the azimuth rotor, an azimuth actuation and control system, a range actuation and control system, and a mechanism for variably controlling range rate and flow volume.

US Patent 5,280,854 to Das also describes a robotic sprinkler head, this one including a nozzle connected to its outlet pipe which produces a jet of water which travels like a projectile and lands at a distance from the sprinkler head to water only a small circular area at that location. The outlet pipe can rotate in both horizontal and vertical planes, the rotation in the vertical plane controlling the distance where water drops. The rotation of the outlet pipe is controlled by a computer, which may also take into account the variation of water pressure when adjusting the vertical angle of the outlet pipe.

US 6,402,048 to Collins describes an accurate horticultural sprinkler system including a unique irritation sprinkler head design. The sprinkler head of the Collins reference is electrically controllable during delivery of water to vary angular position and flow rate of water to limit water delivery to the planted area of interest.

Programmable valves for liquids are also known in the art, such as those shown in US Patents 5,960,813 and 6,257,264 to Sturman et al. These patents disclose solar powered programmable valves, including a single chip computer controller for the valve. The solar cells provide actuating power to a latching solenoid of a pilot operated valve, and programming of the microcontroller causes the valve to operate at subsequent times to fully open or close the valve.

A fluid flow control valve, which is mechanically programmable, to enable the control of flow rate and/or timing of the supply of fluid there through, is described in US Patent 6,047,949 to Beauchemin, Jr.

Another problem encountered in irrigation systems is that of variable water pressure in the main water supply. Thus, there can be surges of water through a sprinkler head, which is likely to break down under such conditions. In order to prevent this, it is desirable to provide a pressure regulator to maintain the pressure in the system at a substantially constant level.

One example of an adjustable pressure regulator is marketed by The Drip Store, Escondido, California, USA. These regulators are used on large systems to increase the pressure at the head assembly, to enable longer runs of tubing with more consistent emitter flow rates.

A pressure actuated control system for sprinkler and irrigation systems is described in US Patent 5,878,953 to Coffman. This multiple section irrigation sprinkler system incorporates pilot operated, pressure actuated and sequenced valve assemblies, and incorporates a device to increase or decrease the water pressure in the water supply lines at a controllable rate. The system includes a dump valve to relieve the water pressure during the pressure reduction cycle, to greatly reduce water hammer effects. The predetermined sequence of water pressure levels is utilized to sequentially activate the pilot operated pressure actuated and sequenced valve assemblies.

Generally, the sprinkler systems described above are incapable of efficiently watering non-circular areas, and the modified sprinklers of the prior art are expensive and complicated to manufacture and maintain. There is thus a widely recognized need for, and it would be highly advantageous to have a computerized sprinkler system which is programmable for efficient irrigation of areas of any shape, without requiring a complicated sprinkler head, but covering all corners and edges of the irrigated area, without wasting water and using a minimum number of sprinklers. SUMMARY OF THE INVENTION

According to the present invention there is provided a sprinkler system including a device disposed upstream of a standard rotary sprinkler, for automatically adjusting water velocity to the sprinkler, thereby controlling a spray distance and an irrigation area of the sprinkler; and means for controlling the device according to data of the irrigation area, for spraying the area substantially in conformity with boundaries of the area.

According to one embodiment of the invention, the device comprises a controllable valve assembly for adjusting water velocity, the valve assembly having an outlet orifice of variable size.

According to a preferred embodiment, the valve assembly controls water velocity supplied to the sprinkler according to a pre-stored pattern.

According to another embodiment, the means for controlling includes computerized control means for generating control signals according to pre- stored data, and using the control signals for automatically adjusting water velocity to the sprinkler.

According to yet another embodiment, the control signals are fed to the valve assembly for automatically varying the size of the outlet orifice, thereby automatically varying the water velocity to the sprinkler.

According to another aspect of the present invention the device includes a controllable pressure regulator for adjusting water velocity to the sprinkler.

According to one embodiment, the pressure regulator controls water velocity supplied to the sprinkler according to a pre-stored pattern.

According to another embodiment, the control signals are fed to the pressure regulator for automatically varying the water pressure, thereby automatically varying the water velocity to the sprinkler.

Further according to the present invention there is provided a sprinkler system including a water supply line; a standard rotary sprinkler coupled to the water supply line; a device disposed in the water supply line upstream of the sprinkler, for automatically adjusting water pressure in the supply line and, in turn, the velocity of the water supplied to the sprinkler, thereby controlling a spray distance and irrigation area of the sprinkler; and means for controlling the device according to pre-stored data of the irrigation area, for spraying the area substantially in conformity with boundaries of the area.

According to another embodiment, the sprinkler system further comprises a conventional valve for providing and preventing water flow to the device.

According to yet another embodiment, the valve assembly includes a variable water valve and at least one electric motor coupled to the variable water valve and arranged and configured to open and close an outlet orifice of the variable water valve to any required size. According to one preferred embodiment the valve assembly includes two oppositely disposed electric motors mechanically coupled to the variable water valve, the motors being controllably coupled to a system computer.

According to another preferred embodiment the valve assembly includes one computer controllable electric motor including a conventional gear system coupled to a variable water valve.

According to one embodiment, the means for controlling includes at least one computer arranged to control the device according to an angular position of the sprinkler.

According to a preferred embodiment, the computer runs a control program with at least three variables: angular position of the sprinkler at each point throughout its axial rotation; distance of the sprinkler from the boundaries of the area at each angular position; and a correlation between the velocity of the water supplied to the sprinkler and the spraying distance of the sprinkler. According to one embodiment, the sprinkler includes an adjustable water outlet having an adjusting screw for adjusting size and shape of the water outlet, to select the spraying spread of the water jet of the sprinkler.

According to the present invention, there is also provided a method for irrigating an area, the method including automatically adjusting the water velocity to a standard rotary sprinkler by means of a device disposed upstream of the sprinkler, thereby controlling a spray distance and irrigation area of the sprinkler; and controlling the device according to data of the irrigation area, for spraying the area substantially in conformity with boundaries of the area. According to one preferred embodiment, the method includes providing water in a water supply line to a standard rotary sprinkler coupled to the water supply line; and automatically adjusting water pressure in the supply line and, in turn, velocity of water supplied to the sprinkler, by means of a device disposed in the water supply line upstream of the sprinkler, thereby controlling a spray distance and irrigation area of the sprinkler; and controlling the device according to pre-stored data of the irrigation area, for spraying the area substantially in conformity with boundaries of the area.

According to a. preferred embodiment, the data are entered by a peripheral device such as a scanner or video camera, scanning a drawing of the irrigation area. Alternatively, the data are entered manually during a learning phase, and stored in a computer for later use.

Further according to the present invention there is provided a kit adapted to be integrated with an existing sprinkler irrigation system having a water supply line and a standard rotary sprinkler, to enable the sprinkler to spray substantially in conformity with boundaries of the area, the kit including a device arranged to be disposed upstream of the sprinkler, for automatically adjusting water velocity to the sprinkler, thereby controlling a spray distance and irrigation area of the sprinkler; and means for controlling the device according to data of the irrigation area. According to one embodiment, the device includes a variable water valve assembly having an outlet orifice of controllable surface area. Alternatively, the device may include a pressure regulator for adjusting water pressure in the water supply line, to provide controlled increase or decrease of water velocity in the water supply line.

BRIEF DESCRD?TION OF THE DRAWINGS

The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein: Figure 1 is a schematic illustration of an irrigation system constructed and operative in accordance with one embodiment of the present invention;

Figure 2 is a perspective view of a variable water valve assembly constructed and operative in accordance with one embodiment of the present invention; Figure 3 is a schematic illustration of an irrigation system constructed and operative in accordance with another embodiment of the present invention; and

Figure 4 is a schematic illustration of an irrigation system in accordance with one embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to sprinkler systems for efficiently irrigating lawns, gardens or other areas of any shape. The disclosed sprinkler system includes a device disposed in a water supply line upstream of a standard rotary sprinkler, capable of automatically adjusting the velocity of the water supplied to the sprinkler, thereby controlling a spray distance and irrigation area of the sprinkler. The system also includes means for controlling the device according to data of an area to be watered, for spraying the area substantially in conformity with the boundaries of the area. For purposes of the present invention, a "standard" sprinkler should be understood to mean an off-the-shelf rotary sprinkler which does not require a mechanism inside the sprinkler head for changing the water pressure or velocity or water outlet angle.

According to a preferred embodiment of the invention, the device includes a valve assembly. According to another embodiment, the device includes a pressure regulator. A preferred sprinkler system includes a water supply line, a standard sprinkler, and a computer controlled valve assembly for changing the water pressure in the water supply line, which changes the water velocity supplied to the sprinkler according to pre-stored data of the contour of the area to be irrigated, thereby controlling the sprinkler's spray distance and enabling it to conform substantially to the outer edges of the irrigated area.

It is believed that, as the size of the outlet orifice of the valve assembly decreases, the water pressure in the supply line increases, thereby increasing the water velocity supplied to the sprinkler, thus increasing the spraying distance. And, conversely, when the outlet orifice of the valve assembly increases, the water pressure in the supply line decreases, thereby decreasing the water velocity supplied to the sprinkler, and decreasing the spraying distance. Alternatively, increasing or decreasing the water pressure in the line, while the diameter of the supply line remains constant, also results in the increase or decrease of water velocity supplied to the sprinkler through the supply line.

It is a particular feature of the present invention that the ability to dynamically alter the distance covered by the water jet from a standard sprinkler permits saving water and using significantly fewer sprinklers than in conventional systems. The system may further include a conventional valve for permitting or preventing water flow through the water supply line. Alternatively, the valve assembly, itself, can also be utilized to permit or prevent water flow through the water supply line. Referring now to Fig. 1, there is shown a schematic illustration of an irrigation system 10 constructed and operative in accordance with one embodiment of the present invention. System 10 includes a water supply line 12 coupled to a valve 14. Valve 14 can be controlled manually or by a system computer 22 as in conventional systems. Water supply line 12 supplies water to a standard sprinkler 16, disposed at any point inside, or adjacent to, an area 18 to be watered. The illustrated system further includes a computer controlled device 20, mounted in water supply line 12, and controlled by system computer 22, for variably adjusting the water velocity in the supply line, thereby controlling the sprinkler's spray distance at any angle of its axial rotation, and as the sprinkler rotates, its irrigation area. Device 20 adjusts the water velocity according to data of the contour of the area to be irrigated, which can be pre-stored in system computer 22.

According to one preferred embodiment of the invention, computer controlled device 20 is adapted and configured to adjust the water velocity in the supply line by means of a variable valve assembly having an outlet orifice of controllable size, to provide controlled increase or decrease of water pressure in the water supply line, thereby controlling the water velocity supplied to the sprinkler. One example of a suitable computer controlled valve assembly is illustrated in perspective view in Fig. 2, and generally designated 30. Valve assembly 30 includes two connectors 32 and 34 for connecting the valve assembly to the water supply line. In the illustrated embodiment, valve assembly 30 includes two oppositely disposed electric motors 36 and 38, mechanically coupled to a variable water valve 40, as by arms 42. Motors 36 and 38 can be controlled by the system computer (not shown in Fig. 2) and arranged and configured to open and close the outlet orifice of variable water valve 40 to any required size, in precise conformity to the computer commands, so as to provide a pre-selected, and preferably pre- stored, dynamically changing water velocity through the supply line to the sprinkler, from which the water is ejected to a desired distance to closely follow the shape of the area to be irrigated.

Alternatively, valve assembly 30 can include a single electric motor comprising a conventional gear system, coupled to variable water valve 40 to control the size of the outlet orifice of the valve. In addition, control valves capable of being controlled by computers are available on the market, such as Series 300 Automatic Control Valves manufactured and marketed by Dorot Ltd., of Kibbutz Dorot, Israel.

The system computer 22 (Fig. 1) runs a computer program which is arranged and configured to provide commands to motors 36 and 38 for controlling valve 40 to open or close its outlet orifice to the desired size. It will be appreciated that the computer program must accommodate at least three variables: (i) the angular position of the sprinkler at each point throughout its axial rotation; (ii) the distance of the sprinkler from the edges of the area at each angular position; and (iii) the correlation between the velocity of the water supplied to the sprinkler and the spraying distance of the sprinkler. It will further be appreciated that such a computer program is readily programmable by those skilled in the art. Needless to say, the location of the sprinkler relative to the area to be watered determines the limits of the irrigation zone of the sprinkler, to be manually set. Preferably, motors 36 and 38 are controlled according to the computer program to change the size (surface area) of the outlet orifice of the variable valve according to the radial position of the sprinkler at each point throughout its axial rotation. The data of the contours of the area to be irrigated can be entered into the computer by a peripheral device, such as a scanner, as by scanning a drawing of the area to be irrigated, and the computer program can be arranged to transform the contour data into commands for motors 36 and 38, to control the outlet orifice size of valve 40 at any angular position of the sprinkler along its axial rotation. The peripheral device can alternatively include a video camera, or any other device capable of inputting to the computer contour data of an area to be irrigated.

Alternatively, the motors may be activated during an initial learning phase by commands given manually by a user utilizing a remote or other controller to change the outlet orifice size of the valve according to the water velocity that is required to obtain the desired distance of water spray. These manual commands are simultaneously fed into the system computer, and recorded in any known fashion for activation of motors 36 and 38 by the computer, on later occasions, for automatic watering. Optionally, device 20 may include a computer controlled pressure regulator (not shown) or other device for changing water pressure in the water supply line at a controlled rate, thereby controlling the water velocity to the sprinkler, and, thus, the spraying distance of the sprinkler.

According to this embodiment of the invention, instead of changing the orifice size of a valve assembly, the water pressure in the supply line can be adjusted, so as to provide a selected water velocity to the sprinkler, at any given time. Thus, an automated water pressure regulator can be provided, to adjust the water pressure in the supply line and the water velocity supplied to the sprinkler in accordance with the rotation of the sprinkler, allowing areas of any shape to be efficiently irrigated with reduced water loss and fewer sprinklers.

Referring now to Fig. 3, there is shown a sprinkler system constructed and operative according to another embodiment of the present invention, and generally designated 50. System 50 is arranged to irrigate a plurality of differently shaped areas 52, 54, 56.

Irrigation system 50 includes a main water supply line 58 coupled to a conventional valve 60, as described with reference to valve 14 in Fig. 1. System 50 also comprises at least one water supply sub-line 62 supplying water to standard sprinklers 64, 66, 68 and 68', which are associated with areas 52, 56, and 54, respectively. It will be appreciated by those skilled in the art that, according to the present invention, sprinklers 64, 66, 68 and 68' may also be disposed outside the boundaries of the areas to be watered.

Each water supply sub-line 62 is coupled to a computer controlled device 70, for variably adjusting water velocity in the supply line, which may be substantially similar to device 20 in Fig. 1. It will be appreciated that each sprinkler associated with an area of a different shape or size requires its own device, if it is desired that all such areas be irrigated at the same time. However, sprinklers such as sprinklers 68 and 68', each arranged to irrigate an area of the same shape and size, and positioned at the same location relative to the area, can share a common device and irrigate both areas at the same time.

Furthermore, because of the possibility according to the present invention of precisely irrigating geometric shaped areas, a large area to be irrigated can be divided among a number of sprinklers, each arranged to cover a selected portion of the total area, such as a square, as schematically illustrated by area 54 in Fig. 3. It will be appreciated that no irrigation overlapping is required, as necessary with conventional irrigation systems, thereby saving water, requiring fewer sprinklers, and providing uniform irrigation over the entire area. According to an embodiment of the present invention, computer controlled device 70 is connected between the main water supply line 58 and a water supply sub-line 62. Alternatively, device 70' can be connected in the supply sub-line 62'. It will be appreciated that, in this case, water is supplied to each sub-line at the pressure required for irrigation of the entire area associated with the sub-line, which can be achieved in any conventional manner.

It will be further appreciated that the system can include several main supply lines, each having its own conventional valve, whether computer controlled or manual, and a valve assembly or pressure regulator, to permit irrigation of different areas at different times of the day and for different durations. A single system computer can control all conventional valves and valve assemblies/pressure regulators to irrigate a plurality of different areas, all, or a group of areas, at once, or each area separately, at different times and for different durations. Alternatively, several computers can be employed in a single system.

According to another embodiment of the present invention illustrated in Fig. 4, irrigation system 80 includes a main water supply line 82 coupled x to a conventional valve 84 (as described with reference to valve 14 in Fig. 1), and one water supply sub-line 86 supplying water to standard sprinklers 88, 90, 92, and 94, which are associated with differently shaped or sized areas 96, 98, 100, and 102, respectively. A computer controlled device 104, substantially similar to device 20 in Fig. 1, is mounted between main water supply line 82 and water supply sub-line 86. Conventional electric control valves 106, 108, 110 and 112, for permitting or preventing water flow, are disposed in supply sub-line 86 between a common computer controlled valve assembly or pressure regulator 104 and sprinklers 88, 90, 92 and 94, respectively. Valve 84, valve assembly 104 and control valves 106, 108, 110 and 112 are all coupled to system computer 114 and controlled thereby. The system computer allows for only one area to be irrigated at a time by closing the control valves associated with the other areas of the system. For example, to irrigate area 96, computer 114 opens valve 84 and control valve 106, closes control valves 108, 110 and 112, and controls valve assembly /pressure regulator 104 according to the contour data of area 96 which was pre-stored in the computer.

It will be appreciated that the sprinkler can include an adjustable water outlet, as known. The size and shape of the water outlet can be adjusted by an adjusting screw, to select the spraying spread of the water jet of the sprinkler. With further reference to Fig. 1, operation of the sprinkler system of this embodiment is as follows. When an area is to be irrigated, valve 14 controlling the main water supply line 12 is opened, and water flows, at the pressure and rate of the mains water supply, or any other water supply arrangement, as known, towards sprinkler 16. Device 20 is mounted in supply line 12 for controlling the water pressure in the supply line, so as to dynamically adjust the water velocity according to a pre-determined pattern, and apply water substantially within the boundaries of the area 18 to be irrigated. Device 20 is activated by system computer 22 according to pre- stored data of the shape and size of area 18 to be irrigated, the location of sprinkler 16 relative to area 18, etc., as described above. According to one embodiment of the invention, the computer feeds the device with control signals according to the pre-stored program, and the valve assembly or pressure regulator adjusts the water pressure in the supply line and thereby the velocity of the water reaching the sprinkler, according to the control signals.

In this way, as the standard sprinkler 16 rotates, it will be supplied with water at velocities which vary relatively to the angular position of the sprinkler along its axial rotation, so as to evenly irrigate the area to be watered substantially within the boundaries of the area, thereby saving water which is not wasted on overlapping or on extending beyond the edges of the area, and evenly covering the entire surface to be watered.

It will be appreciated that the sprinkler system of the present invention can be marketed as a kit for retrofitting to existing irrigation systems. Thus, the invention also includes a kit adapted to be integrated with an existing sprinkler irrigation system including a water supply line and a standard sprinkler, to enable the sprinkler to irrigate efficiently areas of any shape. The kit includes a valve assembly or pressure regulator adapted for insertion into the water supply line upstream of the sprinkler, for adjusting water velocity in the supply line. While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications, and other applications of the invention may be made.

Claims

WHAT IS CLAIMED IS:

1. A sprinkler system comprising: a device disposed upstream of a standard rotary sprinkler, for automatically adjusting water velocity to said sprinkler, thereby controlling a spray distance and an irrigation area of the sprinkler; and means for controlling said device according to data of said irrigation area for spraying said area substantially in conformity with boundaries of the area.

2. The sprinkler system according to claim 1, wherein said device comprises a controllable valve assembly for adjusting water velocity, said valve assembly having an outlet orifice of variable size.

.

3 The sprinkler system according to claim 2, wherein said valve assembly controls water velocity supplied to the sprinkler according to a pre- stored pattern.

4. The sprinkler system according to any of claim 1 - 3, wherein said means for controlling includes computerized control means for generating control signals according to pre-stored data, and using said control signals for automatically adjusting water velocity to said sprinkler.

5. The sprinkler system according to claim 4, wherein said control signals are fed to said valve assembly for automatically varying the size of said outlet orifice, thereby automatically varying the water velocity to said sprinkler.

6. The sprinkler system according to claim 1, wherein said device comprises a controllable pressure regulator for adjusting water velocity to said sprinkler.

7. The sprinkler system according to claim 6, wherein said pressure regulator controls water velocity supplied to the sprinkler according to a pre- stored pattern.

8. The sprinkler system according to claim 6, wherein: said means for controlling includes computerized control means for generating control signals according to pre-stored data, and using said control signals for automatically adjusting water velocity to said sprinkler; and said control signals are fed to a pressure regulator for automatically varying the water pressure, thereby automatically varying the water velocity to said sprinkler.

9. A sprinkler system comprising: a water supply line; a standard rotary sprinkler coupled to the water supply line; a device disposed in said water supply line upstream of said sprinkler, for automatically adjusting water pressure in said supply line and, in turn, velocity of the water supplied to the sprinkler, thereby controlling a spray distance and irrigation area of the sprinkler; and means for controlling said device according to pre-stored data of said irrigation area, for spraying said area substantially in conformity with boundaries of the area.

10. The sprinkler system according to claim 9, wherein said device comprises a valve assembly.

11. The sprinkler system according to claim 10, wherein said device comprises a pressure regulator.

12. The sprinkler system according to any of claims 1 - 11, further comprising a conventional valve for providing and preventing water flow to said device.

13. The sprinkler system according to claims 2 or 10, wherein said valve assembly includes a variable water valve and at least one electric motor coupled to said variable water valve and arranged and configured to open an outlet orifice of said variable water valve to any required size.

14. The sprinkler system according to claim 13, wherein said valve assembly includes two oppositely disposed electric motors mechanically coupled to said variable water valve, said motors being controllably coupled to a system computer.

15. The sprinkler system according to claim 13, wherein said valve assembly includes one computer controllable electric motor including a conventional gear system coupled to said variable water valve.

16. The sprinkler system according to any of the preceding claims, wherein said means for controlling includes at least one computer arranged to control said device according to an angular position of the sprinkler.

17. The sprinkler system according to claim 16, wherein said computer runs a control program with at least three variables: angular position of the sprinkler at each point throughout its axial rotation; distance of the sprinkler from the boundaries of the area at each angular position; and a correlation between the velocity of the water supplied to the sprinkler and the spraying distance of the sprinkler.

18. The sprinkler system according to any of the preceding claims, wherein the standard rotary sprinkler includes an adjustable water outlet, having an adjusting screw for adjusting size and shape of the water outlet, to select a spraying spread of the water jet of said sprinkler.

19. A method for irrigating an area, the method comprising: automatically adjusting water velocity to a standard rotary sprinkler by means of a device disposed upstream of said sprinkler, thereby controlling a spray distance and irrigation area of the sprinkler; and controlling said device according to data of said irrigation area, for spraying said area substantially in conformity with boundaries of the area.

20. A method for irrigating an area to be watered, the method comprising: providing water in a water supply line to a standard rotary sprinkler coupled to the water supply line ; and automatically adjusting water pressure in said supply line and, in turn, velocity of water supplied to the sprinkler, by means of a device disposed in said water supply line upstream of said sprinkler, thereby controlling a spray distance and irrigation area of the sprinkler; and controlling said device according to pre-stored data of said irrigation area, for spraying said area substantially in conformity with boundaries of the area.

21. The method according to either of claims 19 and 20, wherein said data are entered by a peripheral device.

22. The method according to claim 21, wherein said data are entered by scanning a drawing of said irrigation area.

23. The method according to claim 21 , wherein said data are entered by means of a video camera scanning said irrigation area.

24. The method according to claim 21, wherein said data are entered manually during a learning phase, and stored in a computer for later use.

25. A kit adapted to be integrated with an existing sprinkler irrigation system having a water supply line and a standard rotary sprinkler, the kit comprising: a device arranged to be disposed upstream of the sprinkler, for automatically adjusting water velocity to said sprinkler, thereby controlling a spray distance and irrigation area of the sprinkler; and means for controlling said device according to data of said irrigation area, for spraying said area substantially in conformity with boundaries of the area.

26. The kit according to claim 25, wherein said device includes a variable water valve assembly having an outlet orifice of controllable size, to provide controlled increase or decrease of water velocity in the water supply line to the sprinkler.

27. The kit according to claim 25, wherein said device includes a pressure regulator for adjusting water pressure in the water supply line, to provide controlled increase or decrease of water velocity in the water supply line to the sprinkler.