EP0164821A1

EP0164821A1 - Covers

Info

Publication number: EP0164821A1
Application number: EP85301763A
Authority: EP
Inventors: James William Davey
Original assignee: Aquatan Pty Ltd
Current assignee: Aquatan Pty Ltd
Priority date: 1984-03-16
Filing date: 1985-03-14
Publication date: 1985-12-18
Also published as: AU4006085A; MW485A1

Abstract

An air tight water reservoir cover comprises a number of semi-rigid panels (10, 12) joined together along their edges by foldable strips (14). The overall effective area of the cover is varied by the folding and unfolding of the strips (14).

Description

BACKGROUND OF THE INVENTION

The invention relates to covers for reservoirs or the like.
It is preferable if-possible to cover a reservoir not only to reduce evaporation but .also to inhibit or prevent Pollution. of the. water, the latter being caused by airborne contaminants as well as algae and the like. Generally,if there is no oxygen in contact with the surface of the water algae and the like cannot survive or breed.
It is already known to cover reservoirs with highly flexible plastics material which floats on the strface of the water to inhibit evaporation and pollution.

SUMMARY OF TIE INVENTION

According to the invention there is provided an air tight cover for a reservoir which is supported in use on the surface of the water, the cover consisting of a number of panels separated from one another and formed of semi-rigid plastics material, the panels being joined together along their edges by strips of foldable flexible material extending between the panels which are arranged to unfold. and fold to allow the effective overall dimensions of the cover to increase and decrease respectively as required when the reservoir empties and fills.
Preferably, the edges of the panels are provided with ribs to increase the rigidity of the panels. The ribs can also facilitate joining the edges of the panels to the flexible strips and to each other where required.

BRIEF DESCRIPTION OF THE DRAWINGS

A cover for a reservoir according to the invention will now be described by way of example with reference to the accompanying drawings in which:-

Figure 1 is a. schematic plan view of the cover;
Figures: 2A and 2B show the cover in cross-sectional elevation in two configurations covering a full reservoir and an empty reservoir respectively; and
Figure 3 shows a cross-sectional view of a joint in the cover.

DESCRIPTION OF PREFERRED EMBODIWENT

Referring to the drawings, in Figure 1 the cover consists of a central panel 10, of semi-rigid plastic material such as heavy duty polythylene, and four side panels 12 of the same material. The edges of the panels 10 and 12 are joined together by strips 14 and 16 of flexible plastics material, such as Hypalon (Trade Mark), which extend between those edges.
In Figures 2A and 2B it can be seen how the cover is able to change its effective overall dimensions between extreme positions in use. on a reservoir when the reservoir is full and when the reservoir is empty. The flexible strips 14 automatically form folds when. the reservoir is full (see Figure 2A) which unfold cmpletely or almost completely when the reservoir is empty (Figure 2B).
Referring to Figure 3, the panels 10 and 12 have ribs 18 of closed cell foam material attached along their edges which support those edges and also provide firm structures to facilitate mechanical connection between the. edges of the panels and edges of the strips 14. A sand sausage or a number of sand sausages are placed in the folds formed by the strips 14 to cause the folds to form downwards to below the surface of the water to some extent. This not only controls the folds to -form a uniform downward direction along the lengths of the strips 14, but also ensures that the folds can be used to collect rain water from the top of the cover. It is possible to vary the effective width of the strip 14 from one end-of the strip to the other so that-a natural gradient for surface water is provided in practice. This ensures that.the rain water flows or tends to flow to one end of each strip 14 from where it can be pumped away if required..
Normally, conventional reservoir covers are preferably provided with vents or inspection ports and the described cover is generally rigid and strong enough to allow an inspector to walk safely and comfortably across the top of the cover. With flexible covers of the prior art this was often hazardous or not possible.
The panels 10 and 12 may be provided with additional intermediate ribs to improve or increase the overall effective rigidity of the panels.
Similarly, as the panels 10 and 12 may not and need not be fonned necessarily of single.sheets of material, floats can be conveniently provided along the perimeter of separate sheets making up the panels 10 and 12 to facilitate: forming joints along such perimeters. Covers according to the invention may have various configurations and dimensional combinations of semi-rigid and flexible material parts. However, covers according to the invention are formed of predominantly semi-rigid material that is, at least approximately 70% of the total effective maximum surface area is formed of semi-rigid material. material. The portions of flexible material are provided to allow the cover to change its overall effective dimensions as normally required by their folding and unfolding, when and as the height of the water in the reservoir changes.Thus, the cover can remain at all times floating on the surface of the water as the reservoir fills and empties while the extremities of the cover remain firmly secured or anchored to the surrounding ground or perimeter walls of the reservoir as the case may be.
The ribs may be formed of pipes made of plastics or other material. It will be noted that the ribs or pipes and more particularly the strips 14 extending downwards into the surface of the water reduce any tendency in their regions for transverse movement of the cover. This enhances the overall stability of the cover in use.

Claims

1. An airtight cover for a reservoir which is supported in use on the surface of the water, the cover consisting of a number of panels separated from one another and formed of semi-rigid plastics material, the panels being joined along their edges by strips of foldable. flexible material extending between the panels which are arranged to unfold and fold to allow the effective overall dimensions of the cover to increase and decrease respectively as required when the reservoir empties and fills.

2. An air tight. cover according to Claim 1, in which ribs are provided along the underside edges of the panels.

3. An air tight cover according to Claim 1 or 2, in which intermediate ribs are provided attached to the underside of the panels to increase the effective rigidity thereof.

4. An air tight cover according to any one of Claims 1 to 3, in which some of the panels are formed of two or more separate sheets of material joined together.

5. An air tight cover according to any one of Claims 1 to 4, in which the panels comprises at least 70% of the maximum effective plan area of the cover.

6. An air tight cover according to any one of Claims 1 to 5, in which the effective width of at least some of the strips reduces along their length such that when the edges of the strip are separated by the panels moving apart a natural gradient for water drainage along the strip is provided.