GB2438361A

GB2438361A - Irrigation system

Info

Publication number: GB2438361A
Application number: GB0610166A
Authority: GB
Inventors: Graham Gwilliam
Original assignee: ASBESTOSTRIP INNOVATIONS UK LT
Current assignee: ASBESTOSTRIP INNOVATIONS UK LT
Priority date: 2006-05-23
Filing date: 2006-05-23
Publication date: 2007-11-28
Anticipated expiration: 2026-05-23
Also published as: GB2438361B; GB0610166D0

Abstract

A system for irrigating live plant material includes a pressurised source of irrigation liquid 4, 7 and a pipeline 2 for distributing liquid to a plurality of dispensing positions for administration to live plant material. The flow of liquid at each of said dispensing positions is accurately and independently controlled by means of a respective adjustable flow control valve 15 and injector needle 16. The valves have a rotatable control disc with an aperture in registration with a flow control channel of reducing cross-sectional area.

Description

Asbestostrip Innovations UK Limited

PLANT IRRIGATION SYSTEM

TECHNICAL FIELD OF THE INVENTION

This invention relates to the irrigation of living plant material such as plants, trees, shrubs, fruit crops, seeds, cuttings and the like.

BACKGROUND

Water continues to be in short supply in many parts of the world. There are many known forms of plant irrigation system already in use, but in general these lack the ability to accurately control the quantity of liquid which is delivered at different parts of the system. As a result, the existing systems often use more water than is would be strictly necessary to achieve optimum irrigation at each port of the system.

The present invention seeks to provide a new and inventive plant irrigation system which overcomes these shortcomings.

SUMMARY OF THE INVENTION

The present invention proposes a method of irrigating live plant material which includes: -providing a pressurised source of irrigation liquid, -distributing liquid from said pressurised source to a plurality of dispensing positions for administration to live plant material; and -controlling the flow of liquid at each of said dispensing positions by means of a respective adjustable flow control valve such that the rate of delivery of liquid to the plant material at the said dispensing position is accurately controlled.

The invention also provides apparatus for irrigating live plant material which includes: -a pressurised source of irrigation liquid, -a distribution system for distributing liquid from said pressurised source to a plurality of dispensing positions for administration to live plant material; and -a respective adjustable flow control valve for controlling the flow of liquid at each of said dispensing positions such that the rate of delivery of liquid to the plant material at the said dispensing position is accurately controlled.

BRIEF DESCRIPTION OF THE DRAWINGS

The following description and the accompanying drawings referred to therein are included by way of non-limiting example in order to illustrate how the invention may be put into practice. In the drawings: Figure 1 is a general diagrammatic overview of a plant irrigation system in accordance with the invention; Figure 2 is a general view of one of the flow control valves for use in the irrigation system; Figure 3 is an exploded general view of the valve; Figure 4 is an axial section through the assembled valve; and Figure 5 is a plan view through an upper end of the valve body shown in Fig. 4.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to Fig. 1, the plant irrigation system 1 comprises a distribution pipe 2 for distributing water, aqueous fertilizer or similar irrigation liquid to a number of dispensing positions 3 for administration to live plant material. The pipe 2 may be a length of flexible thermoplastic tubing which is fed from a pressurised source of irrigation liquid, four alternative examples of which are illustrated in the drawing. In the first example pressurised water is drawn from a water main 4 via an isolating valve 5 and a double check valve 6. The remaining examples use a refillable pressure vessel 7, such as a 50 litre thermoplastic bottle, which is filled with a quantity of irrigation liquid, when required, through a screw-top sealing closure 8. The pressure vessel may be pressurised by various means. In the second example atmospheric air is pumped into the vessel using a reciprocating hand pump 9. In the third example a pressurising gas such as carbon dioxide or nitrogen is supplied from a cylinder 10, when required, via a control valve 11. The fourth example uses a small electrical compressor pump 12 to raise the air pressure within the vessel 7. Re-pressurisation will normally occur intermittently, although a pressure sensor may be used to automatically control the valve 11 or the pump 12 when the pressure falls. A pressure-relief valve 13 could also be provided to prevent excess pressure build-up within the pressure vessel 7. A pressure of around 3 to 4 bar will normally be sufficient for short distances between the pressure source and the farthest dispensing position, although increasing the pressure to around 10 bar will allow distribution to take place at up to at least 200 metres.

Downstream of the liquid source the distribution pipe 2 includes an isolation (on/off) valve 14, allowing the flow of liquid to be completely stopped when required. Each dispensing position 3 is provided with an individual flow control valve 15 and an injector needle 16. The valves 15 are connected in series along the distribution pipe 2, with an end stop 17 provided after the final valve. The needle 16 is a length of metal tube, typically between 50mm and 1,000 mm long. The needle has a closed end remote from the valve 15 but has a series of perforations along its length, typically each about 0.2 mm in diameter. The needle can be inserted into the soil or other growing medium allowing liquid to be distributed to the roots of the plants in an economical manner without risk of blockage. As with the needle 16.1, at least some of the needles may include an angular portion adjacent to the valve 15 so that they can lie on the surface of the ground.

The structure of the valves 15 will now be explained in more detail with reference to Fig.s 2 to 5. Referring firstly to Fig. 2, each valve 15 has a generally cylindrical body 20 with a pair of diametrically opposed inlet and outlet ports 21 and 22 for connection with sections of the distribution pipe 2. A third port 23 at the bottom end of the body 20 directly receives the injector needle 16. The top end of the body 20 is provided with a cap 24 with a radially projecting flow control lever 25, rotatable about the axis of the body 20. As can be seen from the exploded view of Fig. 3, the lever is part of a control element 26 which is contained within the valve body. The lever 25 is passed through a central hole 27 in the cap 24, which is in turn connected with the body in a bayonet-like manner, having inwardly-directed lips 28 to pass between and locate beneath part-circumferential ribs 29 on the outside of the valve body. The control element 26 has an upper portion 30, adjacent to the lever, which is connected to a drive disc 31 via a narrow stem 32. The stem 32 is aligned with the inlet and outlet ports 21 and 22 so that the flow between the ports is substantially unimpeded. The drive disc 31 has a key formation 34 for drivably engaging a circular sealing plate 35. Thus, rotation of the lever 25 causes corresponding rotation of the sealing plate 35.

Referring now to Fig. 4, the plate 35 makes sealing engagement with a bottom wall 37 of the valve body 20. The wall 37 contains a central stepped aperture 38 to communicate with the third port 23. The plate 35 has a single axial through-aperture 39 which is radially offset from the centre of the plate to register with an aperture 40 in the drive disk 31 and a flow control channel 41 formed in the opposing upper face of the wall 37. As shown in Fig. 5, the channel 41 occupies almost a complete circle, concentric with the axis of rotation of the control element 26, increasing steadily in cross-sectional area from one end to the other. At its widest end, the channel 41 is connected with the stepped aperture 38 via a radial section 42. Thus, a proportion of the liquid flowing through the valve between ports 21 and 22 may pass through the aligned apertures and 39 and flow via the channel 41 to exit through the port 23. The channel 41 acts as a continuously variable restriction allowing accurate control over the rate of flow through the port 23 and injection needle 16, typically ranging from a few drops per minute to around 100 ml per minute at a supply pressure of about 3 bar.

It is thus possible to accurately and independently set the rate at which liquid is distributed through the injection needles at each of the dispensing positions.

It will be appreciated that the features disclosed herein may be present in any embodiment of the invention in any feasible combination. Whilst the above description places emphasis on those areas which, in combination, are believed to be new, protection is sought for any inventive combination of the features disclosed herein.

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Claims

CLAIMS

1. A method of irrigating live plant material which includes: -providing a pressurised source of irrigation liquid, -distributing liquid from said pressurised source to a plurality of dispensing positions for administration to live plant material; and -controlling the flow of liquid at each of said dispensing positions by means of a respective adjustable flow control valve such that the rate of delivery of liquid to the plant material at the said dispensing position is accurately controlled.

2. A method according to Claim I in which each of the flow control valves is connected to a respective injector needle.

3. A method according to Claim 2 in which each injector needle has a closed end and a series of liquid distribution apertures spaced along its length.

4. A method according to Claim 2 or 3 in which the injector needle has an angular section adjacent to the flow control valve.

5. A method according to any preceding claim in which the distribution system includes an isolation valve between the pressurised source and the flow control valves.

6. A method according to any preceding claim in which each of the flow control valves has a valve body with a distribution inlet and outlet and a controlled flow outlet.

7. A method according to Claim 6 in which each flow control valve has relatively movable parts in sealing engagement, one of said parts having an aperture which is in registration with a flow control channel in said other part, and said flow control channel is of reducing cross-sectional area.

8. A method according to Claim 7 in which said parts are rotatable relative to each other.

9. A method according to Claim 8 in which the part having said aperture is rotatable and the part having said flow control channel is fixed with the valve body.

10. Apparatus for irrigating live plant material which includes: -a pressurised source of irrigation liquid, -a distribution system for distributing liquid from said pressurised source to a plurality of dispensing positions for administration to live plant material; and -a respective adjustable flow control valve for controlling the flow of liquid at each of said dispensing positions such that the rate of delivery of liquid to the plant material at the said dispensing position is accurately controlled.

11. Apparatus according to Claim 10 in which each of the flow control valves is connected to a respective injector needle.

12. Apparatus according to Claim 11 each injector needle has a closed end and a series of liquid distribution apertures spaced along its length.

13. Apparatus according to Claim 11 or 12 in which the injector needle has an angular section adjacent to the flow control valve.

14. Apparatus according to any of Claims 10 to 13 in which the distribution system includes an isolation valve between the pressurised source and the flow control valves.

15. Apparatus according to any of Claims 10 to 14 in which each of the flow control valves has a valve body with a distribution inlet and outlet and a controlled flow outlet.

16. Apparatus according to Claim 15 in which each flow control valve has relatively movable parts in sealing engagement, one of said parts having an aperture which is in registration with a flow control channel in said other part, and said flow control channel is of reducing cross-sectional area.

17. Apparatus according to Claim 16 in which said parts are rotatable relative to each other.

18. Apparatus according to Claim 17 in which the part having said aperture is rotatable and the part having said flow control channel is fixed with the valve body.

19. A method of irrigating live plant material substantially as described with reference to the drawings. - 20. Apparatus for irrigating live plant material substantially as described with reference to the drawings.

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