GB2338879A - Self-regulating irrigation system - Google Patents

Description

2338879 A NATURAL FLOW IRRIGATION SYSTEM The present invention relates to

a system of irrigation which can be used for household plants,horticulture or agriculture in which the water flow through the unit is controlled entirely by the requirement of the plant's roots.

There are many irrigation systems in present use, but to the best of my knowledge all are operated by switch control either manual or mechanical, which can result in water wastage, as for example in the case of overhead spraying where a large amount is lost through evaporation. And in root watering systems,as for instance where perforated pipes are used. Overwatering at times is certain to occur, for example during rain. How can it be easily established just how wet the soil is at the plant's roots The present invention provides a cheap and simple answer to these and other problems with a longlife system which once installed allows plants to extract from it just the correct amount of water they require and when the soil is naturally damp, cease to flow.

It has a further great advantage in the fact that dissolvable fertilizers can be introduced into the water of the system when required, to be extracted by the plants roots directly,so preventing waste and possible run-off of access into waterways.

--2 The specific embobiment of the invention is now described by way of example with reference to the accompanying drawings Figure 1 illustrates a cutaway section side view of of the system's water storage header tank. 1.2 the inlet pipe controlled by for example'a float valve. Connected into the side of the tank is a water delivery tube 1.3. This tube is of the required diameter to carry water to the furthest point of the system and is of a flexible nature e.g. plastic. But it must be sufficiently strong to withstand the outside pressure that will be placed upon it,so that it will not be squeezed flat and the flow stopped. The reason for this will become clear later in the description. The tube must also be porous and able to lose water along it's entire length.eg. A slit along one side.

Totally surrounding the delivery tube is another of a larger diameter and is a casing tube as shown 1.4 This tube is also fastened to the side of the tank, but has no need of direct connection to the water. It is made from a porous flexible material preferably such as a spunbonded geotextile of a rot resisting nature as used in road construction to prevent the upward penetration of silts into the aggregate. It must be of sufficient strength to withstand the required internal pressure placed upon it, but at the same time allow free water flow through it's sides.

In the space between the delivery tube and the inner wall of the casing tube, there is alayer of a substance that will absorbe and 3 swell upon contact with water. For example water absorbing poly crystals or certain clays. The water gel crystals are the prefered option.On contact with water they swell to many times their dry size & do not deteriate with use.

Figure 2 shows in larger detail the tubes aRd gel layer as described. 2.1 the side of the header tank. 2.2 the outlet pipe from the tank onto which the delivery tube 2.3 is connected. The cut slit running down the side of the delivery tube is shown 2.4.

2.5 shows the outer casing tube with the side cutaway to show the delivery tube surrouned by the gel crystals 2.7. 2.6 illustrates where the casing tube is fastened to the header tank.

Figure 3 shows a cut through facing view of the complete water feeding system. 3.1 th e outer casing. 3.2 the gel crystals. 3.3 the delivery tube running through the centre with the side slit marked.

Other feeding lines can be taken directly as shown from the header tank, or branching off a main line as at 1.5.

The feed lines are installed at the desired depth required for various crops below the soil and can be ploughed in by the use of, a a mole plough, or trenched. ' Once installed in the desired position water is fed into the header tank, which passes through the delivery tube into the gel crystals which absorbe it and swell and place pressure upon the sides of the delivery tube closing and sealing the slit. At the same time the pressure of the gel against the inside of the outer casing tube completely seals this also and the water flow is then restricted to the passage through the centre of the delivery pipe, as it passes through it the water escapes where the slit still --remains open until the whole feeding pipe is sealed along the entire length. It will then be in fact a tube filled with encased water which can be moved around without any loss if desired. When the water is extracted from the feed-line by the fact that the soil surrounding it is drying out, because it is used by.the plant. Then the process is reversed. The gel relaxes it's pressure in that place and the water seeps,into it and it swells and seals again. Actually as can be seen, if water remains in the header tank the feedpipe and the soil around it never really dries out. In wet conditions eg. after rain. The pipe remains sealed.

Sizes and amounts of crystals or absorbent material to be used have not been given as this obviously is dicated by the user's requirement. And other types of materials other than those named can successfully be used to ob tain the desired savings. These would be considered to fall within the-scope of the..invention.

Although the water supply source has been named and illustrated as a header tank for purposes of explanation,it can of course be any clean water and indeed if the water is free of air and the water duct is quite airtight throughout the system, then it could be situated a long distance away from the point where it will be actually needed, also below ground level.

Also although in the illustration a continuous slit is shown extending along the entire length of the delivery tube, this can be a question of choice guided 'by requirement and the tube pierced accordingly.

Sizes and amounts of crystals or absorbent types of material to be used have not been given, as this is dictated by the need and requirement. Many other types of materials other than those that have been named can be successfully used in the manner as described to obtain the desired results and water savings. these would be considered to fall within the scope of the invention.

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Claims (7)

1 An irrigation system the flow of which is controlled by the requirement of the environment and plant life it supports which consists of a porous central water supply duct connected to a water supply source which is completely surrounded by-a-medium which expands upon contact with water tothe extent that it will restrict the flow from the porous duct when it is encased between it and a flexible non-expandable porous outer skin due to the pressure exerted by the expansion and allows the flow from the duct to resume as the medium contracts as the pressure is relaxed due to the water being extracted from it through the encasing skin by plant life and environmental demand.

2 An irrigation system as described in claim 1 which is capable of providing water to plants by a natural means from a source which can be either above or below ground level.

3 An irrigation system as described in claims 1 & 2 in which the porousity of the materials used in it's construction is such that it will permit the passage of water and air but prevent penetration by a dry powdered expanding medium.

4 An irrigation system as described in the previous claim where the materials used in it's construction are of a non-degragable nature.

5 An irrigation system as described in the prevoius claims in which the central water carrying duct is made from a material strong 7 enough to withstand the pressure applied by the surrounding expanding medium to ensure that it will not collapse under it consequently resticting the flow.

6 An irrigation system as described in the prevoius claims where the porous outer skin is of suffient strength to prevent any rupturing when placed under pressure f rom the expanding medium which it contains.

7 An irrigation system as claimed in the previous claims substantially as described in the specification with reference to and as illustrated in the accompanying drawings.