GB2409702A - Self erecting rainwater collection tank - Google Patents

Abstract

A tank (1) comprises a waterproof floor (2) , semi-rigid continuous waterproof walls (4), a flexible seal (5) joining them and acting as a hinge, so that when empty the walls extend generally parallel to the floor. When rainwater collects on the floor it acts on the walls to urge them to a substantially vertical position. Preferably a portion of the wall (11, Figure 3) extends beyond the join with the hinge to protect the hinge. The tank may optionally include a tap, overflows, a pump, cover and/or water sterilisation means.

Description

RAINWATER COLLF,CTION TANK The present invention relates to a flexible

container for the capture and storage of rainwater.

More particularly' but not cxclusivcly, it relates to such a container which may easily be stored when not in uses but which automatically deploys as rain is captured therein.

In many parts ol' the world, lack ol' water for drinking or irrigation is a major problem.

Frcqucntly droughts are not the result of low raint'all but due to the rainfall being concentrated in brick, heavy downpours, either at particular times of the year or at unpredictable intervals, spaced by extremely dry spells. When the rainfall does arrive, the ground is often so dry, cracked and porous that the rain immediately soaks away deep underground. It is therel'orc not available for humans and livestock to drink, and only highly adapted plants, for example with very deepreaching roots, can benefit from it -- certainly very low useful crops are able to grow under such conditions. Even it'the rainwater reaches an underground aquil'er it may not be practicable to dig a well down to the aquifer and pump the water back to the surface, or the water may become polluted.

In other regions, problems may arise from the water falling in such sudden downpours flowing rapidly off' the surl'ace of the land into watercourses. While this water may perhaps be usable for irrigation, it will almost certainly be so heavily laden with silt (or worse) as to be undesirable as drinking water. Ilere too, water will be at its cleanest in the form of rain, but may easily become polluted once it has fallen.

It is hence desirable in such situations to capture rainwater before it can soak or flow away.

Guttering to collect run-oi'i' from rooks is not applicable in many regions, both on grounds of cost and because local building styles are incompatible. Large-scale dams and reservoirs require massive investment and elaborate inl'rastructure. Masonry tanks have been used in some parts of the world to collect monsoon water for irrigation, but they still involve a significant investment to build, and need regular maintenance and cleaning to remove silt and the like.

Transportable or temporary structures need to be sufficiently robust to avoid leaks, but easy to move to where they are needed and easy to put into action. Where rainfall may arrive at short notice or at night, there is little benefit in a structure which takes significant time or labour to assemble. Ideally, a structure or apparatus should be adapted to be lel't in place to collect water without needing any attention.

It is hence an object of the present invention to provide apparatus to capture and hold rainwater which is ease to transport and store, requires a minimum of el'fort to emplace, and automatically collects rainwater without human intervention.

According to a first aspect of the present invention, there is provided a rainwater collection and storage apparatus comprising waterproof floor means and semi-rigid continuous waterproof wall means, so linked to the floor means by flexible joint means that, in an empty configuration of the apparatus at least a majority of the wall means extends generally parallelly to the floor means while rainwater collecting on the floor means may act on the wall means to urge it towards a full configuration of the apparatus in which the wall means extends substantially vertically upwardly from the floor means.

Preferably, the floor means is flexible so as to conform generally to a surface on which it is placed.

Advantageously, said flexible joint means comprises a strip of material of greater flexibility than either the floor means or the wall means, extending sealingly between a peripheral zone of the floor means and a zone of the wall means adjacent its lower edge.

A portion of the wall means and/or the floor means may extend beyond a line along which said strip is mounted thereto, for example so as to shield said strip.

Preferably, the apparatus has a generally circular floor means and is, in its full configuration, generally cylindrical.

The apparatus is preferably provided with selectably operable outlet means through which rain water collected therein may be dispensed.

Advantageously, said outlet means comprises tap means mounted to the wall means.

Alternatively or additionally, the outlet means may comprise pump means connected to an interior of the apparatus, optionally submersible pump means.

Said pump means may be electrically powered, optionally by solar or windpowered electricity generating means.

The outlet means may be provided with filtration means.

The outlet means may be provided with sterilising means, such as water sterilising means employing ultraviolet light.

The apparatus may be provided with overflow means to lead excess collected rainwater controllably away therefrom.

The apparatus may be provided with cover means, detachably mountable thereto in said full configuration.

Said cover means may thus prevent ingress of insects and/or dust, and/or retard evaporation of collected rainwater.

According to a second aspect ol the present invention, there is provided a method for collecting, storing and dispensing rainwater comprising the steps of providing apparatus as described in the first aspect above, placing it in its empty configuration on a substantially level surface, allowing rain to collect therein and thereby erect it into its full configuration, and dispensing collected water therel'rom.

Embodiments of the present invention will now he more particularly described by way of example and with reference to the accompanying drawings, in which: Figure 1 is a cross-sectional of a peripheral zone ova first tank embodying the invention, in an empty, collapsed conl'iguration; Figure 2 is a cross-sectional elevation ol'a peripheral zone of the tank shown in Figure 1, in a full, erect configuration: Figure 3 is a cross-sectional elevation of a peripheral zone of a second tank embodying the invention, in a partially-full configuration; Figure 4 is a plan view of a circular tank embodying the invention, in an empty, collapsed configuration; and Figure 5 is a perspective view of the tank shown in Figure 4, in a full, erect configuration.

Referrhlg now to the Figures, and to Figure 1 in particulars a rainwater collection tank 1 comprises a base membrane 2 ol'tougll, waterproof material, sufficiently flexible to conform generally to a ground surface 3 on which it is laid but resistant to being punctured by sharp stones, thorns and the like. A continuous wall membrane 4 comprises a tough, waterproof material, stiffer than that of the base membrane 2 and is linked to the base membrane 2 around a periphery thereof by a hinge membrane 5 comprising a waterproof material significantly more flexible than either the base membrane 2 or the wall membrane 4. The flexible hinge membrane 5 allows the wall membrane 4 to extend generally horizontally, when the tank 1 is empty, overlying the base membrane 2 adjacent a majority of its periphery, as shown.

The tank 1 is hence relatively convenient to store and transport, and can be dragged into position on a generally level piece ol' ground 3 as required.

When rain 6 begins to fall, it will collect and pool on an upper surface of the base membrane 2. As water collects, it will flow between the base membrane 2 and the wall membrane 4.

As the water level rises further, it will begin to urge the wall membrane 4 outwardly and, since the hinge membrane 5 allows the wall membrane 4 to pivot freely with respect to the base membrane 2, upwardly into a substantially upright position.

Ultimately, the collected rainwater 7 will hold the wall membrane 4 tautly in a substantially upright position, as shown in Figure 2. 'I'he semi-rigid wall membrane 4 should not bow outwardly to a significant extent due to water 7 pressure. The tank] el'l'ectively erects itself as it fills.

One or more overflows 8 are provided adjacent an upper rim of the wall membrane 4. 'I'hese may be simple apertures h1 the wall membrane 4 or overflow pipes as shown. Should the tank 1 be on a sloping ground surface 3, or should the rain 6 be sufficient to overfill the whole tank 1, the overflow or overflows X allow excess water to leave the tank I in a controlled fashion. Otherwise, a sudden local overflowing of water 7, surging over the upper rim of the wall membrane 4, might wash away the ground 3 beneath that part of the wall membrane 4, undermining it, or it might lead to localised buckling of the wall membrane 4, and significant further escapes of collected water 7. The or each overflow X is preferably provided with a Byscreen or filter to prevent ingress by insects (see below).

In the embodiment shown, a simple drain cock 9 arrangement is provided, to tap ol'f water 7 from the tank I as required. This may be provided with an in-line filter (not shown) to remove particulate matter from the water 7, such as airborne dust which may have settled on the base membrane 2 before the rain 6 fell.

As an alternative, a conventional submersible pump could be located within the tank 1, resting on the base membrane 2. Such a pump could be powered by electrical batteries, or more appropriately for many of the regions in which sucl1 a tank would be deployed, by a solar power or wind- power arrangement. In this case, the in-line filter could be supplemented by an ultraviolet water sterilization unit for added safety.

Once the rain 6 is over, a thin plastic cover membrane 10 can be fitted to the tank 1, mounted to the upper rim ol'the upright wall membrane 4 by clips, studs, hooks and eyes, or any other convenient temporary attachment means. This cover membrane I () retards evaporation of the collected water 7, and prevents access by airborne dust or by insects, flies, mosquitoes or the like seeking to lay their eggs. Alternatively or additionally, the tank may be provided with a waterpervious but insect- proof cover, such as flyscreen material of gauge allowing free passage of rainwater.

Once the water 7 level in the tank I has run low, the cover membrane 10 is removed again, in readiness for the next rainl:all. Ideally, the dregs of the water 7 collected in the tank 1 would be used to clean out an interior of the tank I before re-use - even with the precautions above, there is always a chance of' some dust or other contamination entering the tank 1 when in use, and blocking pumps or l'ilters if allowed to accumulate.

A modified version of the rainwater collection tank is shown in Figure 3. The tank I shown in Figures I and 2 has its flexible hinge membrane 5 mounted to its wall membrane 4 along a lower (when upright) margin thereof. However, the wall membrane 4 of'the tank shown in Figure 3 is provided with an extension portion 11, which extends beyond a point at which the hinge membrane 5 is joined to the wall membrane 4.

This extension portion 11 may bring several benefits. As the wall membrane 4 pivots towards an upright configuration under the pressure of' the collected rainwater 7, a lower rim of the extension portion 11 may engage with the ground 3, providing a firmer pivot point.

I'he extension portion 11 also helps to shield the flexible hinge membrane 5 from damage - being the most flexible part ol' the tank 1, it will also probably be the most vulnerable to being punctured.

The individual membranes 2, 4, 5 are either bonded, electronically stitched or ultrasonically welded, one to the other, so as to form tough, waterproof, flexible joints.

A particularly useful shape for such a tank is generally circular, as shown in Figures 4 and 5.

When the tank is full, as in Figure 5, the collected water 7 presses evenly outwardly on the cylindrical wall membrane 4, holding it in a very stable configuration. When the tank is empty, as in Figure 4, the wall membrane 4 folds over generally horizontally inwardly to overlie the base membrane 2' around a majority of its circumference, while folding generally outwardly over two smaller, generally diametrically opposed zones 4a. (Other patterns of folding are possible, but this is the simplest dei'onnational mode of an unsupported cylindrical surface).

I'here are clearly transitional zones between the outwardly-l'olding zones 4a and a remainder of the wall membrane 4 in which the semi-rigid wall membrane 4 is held clear of the plane of the base membrane 2. 'I'his eases the initial inflow of collected rainwater between the wall membrane 4 and the base membrane 2, to begin lilting the wall membrane 4 towards its upright configuration, as shown in Figure 5.

While other base membrane 2 shapes and wall membrane 4 profiles are possible, the generally circular/cylindrical fond shown is probably the most stable and reliable in use.

Figure 5 also shows how an in-1ine filter 12 may be attached to the drain cock 9 to remove particulate solids from water dispensed from the tank 1.

The tanks of the present invention are thus relatively cheap and simple to construct, and easier to transport than the raw materials needed t'or a masonry tank, or a tank provided with a supporting frame. It can either be left in a convenient position to catch rain as and when it occurs, or rapidly dragged out of storage as soon as rain threatens. Once it is Iying substantially flat on the ground, it will collect any rain l'alling thereon' automatically raising its walls as it fills.

In the regions of the world in which such tanks would be of greatest use, single rainstorms can easily deposit a measured rainfall of twelve inches or more' so a tank can collect useful amounts of water without needing to have water channelled into it from a wider catchment area. (Nevertheless, such a tank may also be used as a reservoir connected to a wider collection arrangement if so desired).

With minimal cleaning and maintenance, such a tank can be re-used many times. In conjunction with solar or wind-powered pumps, filters, and sterilization apparatus, a supply of drinking water up to potable quality by developed world standards can be achieved. Even in its most basic form, the tank allows the provision of water likely to be of better quality than could be obtained from wells or watercourses.

Claims (11)

1. A rainwater collection and storage apparatus comprising waterproof floor means and semi-rigid continuous waterproof wall means, so linked to the floor means by flexible joint means that, in an empty configuration of the apparatus at least a majority of the wall means extends generally parallelly to the floor means while rainwater collecting on the floor means may act on the wall means lo urge it towards a full configuration of the apparatus in which the wall means extends substantially vertically upwardly from the floor means.

2. An apparatus as claimed in claim 1, wherein the floor means is flexible so as to conform generally to a surface on which it is placed.

3. An apparatus as claimed in either claim I or claim 2, wherein said flexible joint means comprises a strip oi material of greater flexibility than either the floor means or the wall means, extending sealingly between a peripheral zone of the floor means and a zone of the wall means adjacent its lower edge.

4. An apparatus as claimed in any one of the preceding claims, wherein a portion of the wall means and/or the floor means extends beyond a line along which said strip is mounted thereto, so as to shield said strip.

5. An apparatus as claimed in any one of the preceding claims, wherein the apparatus has a generally circular floor means and is, in its full configuration, generally cylindrical.

6. An apparatus as claimed in any one of the preceding claims, further provided with selectably operable outlet means through which rain water collected therein may be dispensed.

7. An apparatus as claimed in claim 6 wherein said outlet means comprises tap means mounted to the wall means.

8. An apparatus as claimed in claim 6, wherein the outlet means comprises pump means connected to an interior of the apparatus, optionally submersible pump means.

9. An apparatus as claimed in any one of claims 6 to 8, wherein the outlet means is provided with sterilising means, such as water sterilising means employing ultraviolet light.

10. An apparatus as claimed in any one of the preceding claims, further comprising cover means to prevent ingress of insects and/or dust, and/or retard evaporation of collected rainwater, detachably mountable thereto in said full configuration

11. A rainwater collection and storage apparatus substantially as described herein with reference to the 1; igures of the accompanying drawings.