GB2331325A

GB2331325A - Fastening for floating cover

Info

Publication number: GB2331325A
Application number: GB9808092A
Authority: GB
Inventors: Milivoy Peter Grkinic
Original assignee: DRC Polymer Products Ltd
Current assignee: DRC Polymer Products Ltd
Priority date: 1998-04-17
Filing date: 1998-04-17
Publication date: 1999-05-19
Anticipated expiration: 2018-04-17
Also published as: GB9808092D0; GB2331325A9; ZA985062B; GB2331325B

Abstract

A floating cover for reservoirs comprises a plurality of panel units fastened together by fastening means comprising a male member 1 and a female member 2, the male member having a head 3 and a shank 4 having a plurality of teeth 5, the female member having a collar 7 having a bore 8 with mating teeth therein to co-operatively engage with the teeth of the male member. Female members fasten each of two panel edges to the male shank.

Description

2331325 FLOATING COVER

Field of the Invention

The present invention concerns improvements in and relating to floating covers suitable for use to cover reservoirs, settling ponds or other large bodies of water. The present invention also concerns novel fastening means for fastening together the ends of overlapping panels or other structural members.

Background to the invention

Unless they are sub-terranean, water reservoirs are inherently vulnerable to depletion by excessive evaporation during periods of low rainfall and high temperatures. Over recent decades this has begun to prove a substantial problem even in the United Kingdom where there is comparatively high rainfall throughout the year. The problem is far greater in more add regions of the world.

In order to reduce evaporation losses but also to reduce airborne pollution, a number of covering systems have been developed, many making use of plastics sheeting to cover the expanse of the body of water.

More recently, covers have been developed comprising a plurality of linked panels. For the larger bodies of water such modular covers are far more practical to deploy and manoeuvre. One example of a prior covering system comprising a plurality of sealed panel units which are linked together by a system of cables to cover settling ponds is described in US patent US 5,400,549. The covering in the case of that patent is specifically adapted to use on settling ponds and serves to reduce gas and odour emissions and to provide thermal insulation to enhance biodegradation of organic materials in the settling pond.

1 Whereas the modular covering described in US 5, 400, 549 is more easy to manoeuvre than earlier coverings it does require a substantial amount of labour to install over any large expanses of water and larger areas of covering are vulnerable to uplift and dislodgement when exposed to high winds. For the small settling ponds in sheltered locations and situations where it is feasible to secure the periphery of the cover in anchoring trenches this may not be a major problem. However, for large open expanses of water the installation time and the risk of substantial wind uplift and dislodgement represent major drawbacks.

SummaM of the Invention According to a first aspect of the present invention there is provided a floating cover for reservoirs or other large bodies of liquid, which cover comprises a plurality of panel units, each panel unit being fastened to each adjacent panel unit, directly or indirectly, by fastening means, said fastening means each comprising a male member and a female member, the male member having a head with a substantially straight and substantially rigid shank upstanding therefrom, the shank being provided with a plurality of teeth, the female member being a collar having a bore with mating teeth therein to co-operatively engage with the teeth of the male member to allow the shank of the male member to enter the bore of the collar but prevent withdrawal.

By use of this novel fastening system the assembly of the cover by fastening together of the panels is made simple, quick, efficient and reliable.

According to a second aspect of the present invention there is provided a fastening means for fastening together a pair of panels or other structural elements, which fastening means comprises a male member and a female member, the male 2 member having a head with a substantially straight and substantially rigid shank upstanding therefrom, the shank being provided with a plurality of teeth, the female member being a collar having a bore with mating teeth therein to co-operatively engage with the teeth of the male member to allow the shank of the male member 5 to enter the bore of the collar but prevent withdrawal.

The teeth are inclined to provide for the movement of the shank of the male into the female but prevent withdrawal. The fastening means differs markedly from a cable tie especially in the adaptation of the shank to be sufficiently rigid to be substantially straight and upstanding from the head, adapting the fastening means for use like a nut-and-bolt, with the male member penetrating two structural members to be fastened together and secured by the female member.

According to a third aspect of the present invention there is provided a method of assembling a floating cover for a reservoir or other large exposed body of liquid, which method comprises:

(i) providing a cover having a plurality of panel units which when linked together form the cover and providing fastening means to fasten together adjacent panel units, which fastening means comprise a male member and a female member, the male member having a head with a shank upstanding therefrom, the shank being provided with a plurality of teeth, the female member being a collar having a bore with mating teeth therein to co-operatively engage with the teeth of the male member to allow the shank of the male member to enter the bore of the collar but prevent withdrawal; (ii) offering up the male member of the fastening means to an edge of a panel with the shank of the male member passing up through an aperture in said edge; 3 (iii) fitting a said female member over the shank of the male member to fasten the female member to the male member on the opposite face of the panel unit edge and with a portion of the shank of the male member protruding therefrom; (iv) offering the protruding part of the shank of the male member up through an aperture in an edge of an adjacent said panel unit; and (v) fastening a further said female member over the part of the shank of the male member protruding up through the edge of the further adjacent panel unit, thereby securing said panel to said adjacent panel.

By securing the male member to the first panel unit by the first female member before mounting the second panel unit and second female member, handling of the panel units in assembly of the cover is greatly facilitated. Furthermore, by having a female member of substantial height, a substantial gap between panel units of the assembled cover for drainage of rainwater from the cover into the reservoir is provided for.

According to a fourth aspect of the present invention there is provided a floating cover for reservoirs or other large expanses of exposed liquid, which cover comprises a plurality of panel units linked together in use with each adjacent panel unit fastened to its neighbour, wherein the floating cover further comprises one or more anchoring means or ballasting means mounted to the floating cover. Such anchoring or ballasting means are suitably provided mounted to the cover at the overlapping edges of the adjacent panel units or may be integral to the panel units.

In one preferred embodiment the floating cover is held down by a weight system which is adapted to allow the cover to rise and fall with the water level of the 4 reservoir but to resist air uplift of the cover. Suitably the weight is suspended beneath the cover via a pulley.

In an alternative preferred embodiment one or more drag elements are suspended from the cover, in use, to provide drag counteracting any uplift movement. The drag elements may suitably comprise large planar baffles or opentopped receptacles.

In one particularly preferred embodiment the or each drag element is formed as an intermediate bridging unit between the panel units and comprises a chamber which may be filled with a fluid medium, preferably water, to a desired level to maintain the buoyancy of the floating cover but resist uplift. In the context of the method of the third aspect of the invention it should be understood that in that method the first panel unit may be fastened by the fastening means to the intermediate bridging unit and the bridging unit then fastened by further said fastening means to the adjacent panel unit.

Alternatively, one or more of the panel units may be adapted to partially fill with water, or other ballasting fluid to provide a ballasting function.

In all embodiments the panel units may be filled as appropriate with an insulating foam or other lightweight filling and may be covered by an impermeable membrane e.g. a biogas cover.

Brief Description of the Drawings

Preferred embodiments of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, wherein:

Figure 1 is a perspective view of a male member of a novel fastening means of the present invention suitable for fastening together panel units of a modular floating cover for reservoirs.

Figure 2 is a perspective view of a fastening means female member to co5 operatively engage with the male member of Figure 1.

Figure 3 is a perspective view from above of four panel units of a modular floating cover of the present invention.

Figure 4 is a side elevation view of a panel unit of the Figure 3 embodiment and showing a fastening means fastened to one edge of the panel unit.

Figure 5 is a view similar to that of Figure 4 but illustrating a second panel unit mounted and fastened to the first panel unit edge by the fastening means.

Figure 6 is a perspective view of a weighted anchoring means of the present invention.

Figure 7 is a perspective view of a drag element mounted to the floating cover suspended therebeneath.

Figure 8 is a transverse sectional view of a drag element to reduce uplift which comprises an intermediate bridging unit/ballast module.

Figure 9 is a perspective view of the ballast module of figure 8 in position in the cover, bridging between two adjacent panel units.

Figure 10 is a sectional view similar to that of Figure 4, showing one edge of a panel unit where the panel unit has been modified to itself serve as a ballast module.

Description of the Preferred Embodiments

Figure 1 and Figure 2 illustrate a novel fastening means suitable for securing together the adjacent panel unitsimodules of a floating reservoir cover. The 6 fastening means comprise a male member 1 and a female member 2. These two members are formed of a plastics polymer which may be nylon or another suitable material.

The male member 1 is moulded to have a discoid head 3 and an upstanding stake-like shank 4 - in other words, the shank 4 extends substantially perpendicularly from the head 3 and is sufficiently rigid to maintain this substantially perpendicular orientation to facilitate insertion through an aperture in one of the structural members to be connected to another.

The shank 4 is provided with a plurality of teeth 5 each of which is inclined away from the head 3.

The female member 2 is illustrated as moulded with a discoid base portion 6 and rectangular body portion 7. The shape or configuration of the female member 2 is, however, open to a substantial amount of designer freedom the differentiation into a base portion 6 and body portion 7 is not essential. However, what is essential is that the female member 2 has a bore 8 therethrough which has at least one and preferably a plurality of teeth therein to co-operatively engage with the teeth 5 of the male member 1 The inclination of the teeth 5 of the male member 1 enables the shaft 4 of the male member 1 to be inserted through the bore 8 of the female member 2 in one direction but prevents movement in the reverse direction, i.e. prevents its withdrawal.

In Figure 3, the fastening means 1, 2 are shown in use with male members 1 projected upwardly through an aperture 11 in a flattened edge portion 9 of each panel unit 10 a-d for forming the cover. The panel units 10 a-d are each formed of a suitable tough material such as flexible poly- propylene alloy or SCP1E and suitably 7 i 1 1 are filled with an insulating foam such as closed cell polystyrene. Each male member 1 projecting up through an aperture 11 is secured in place straight away by placing a female member 2 over the shank 4 thereof. The next panel 10c to be joined to the already interlinked panels 10 a-d is simply lifted into place with apertures 11 in the edge 9 thereof being mounted over the protruding shanks 5 of the male members 1. The latest panel unit 10 c is then simply fastened in place by engaging a further female member 2 on that part of the shank 1 that protrudes up through the aperture 11 in the latest panel unit 10c. This simple procedure is repeated as many times as necessary to build up the cover from the individual modules/panel units 10. it will be appreciated immediately that the handling of the panels during assembly is greatly facilitated. At no stage does the user have to clamp the fastening members from beneath which would prove difficult to do. By following the procedure the floating cover can be made up from the modules conveniently and rapidly.

In practice, the modules will be assembled together sequentially with the first modules being pushed out and floated on the surface of the body of water and as each further successive module is added the cover is floated out further over the body of water, thereby making the job of assembly comparatively less laborious. Much of the weight of the assembled cover is borne by the water and the assembler needs only to raise one panel unit at the point of joining that panel unit to the rest.

Turning now to Figure 6, this shows an arrangement for anchoring the assembled floating cover to resist wind uplift and dislodgement of the floating cover in use.

8 The anchoring system comprises a pulley 12 suspended from the cover suitably by a cable 13a secured to one of the apertures 11 in an edge 9 of a panel unit 10.

A pair of weights 14, 15 are secured at opposite ends of a second cable 13b suspended over the pulley wheel of the pulley 12. One of the weights 15 is substantially lighter than the other 14. The heavier weight 14 provides a substantial anchoring action while the lighter weight 15 is able to resist wind uplift but will not prevent the cover rising as the level of water in the reservoir rises.

The heavier weight 14 may, if desired, be firmly embedded in the base of the reservoir or else be sufficiently heavy that even the strongest uplift forces to be encountered are effectively resisted.

An example of wind uplift calculation is given hereinafter and provides a model for the magnitude of uplift force likely to be experienced and also shows how this differs between the centre of the cover and the perimeter.

9 Example Wind Uplift Calculation Design windspeed Vs = V x S1 x S2 x S3 x S4 Basic wind speed x Topography Factor x Ground roughness x S1 1.00 S2 1.09 x Statistical factor Design windspeed S4 1.00 Vs In mls 43.60 Dynamic load q K Vs2 0.61311000 x W2 1,900.96 q in M m2= 1.17 Wind Loadings External pressure -cpe Internal pressure - CpiLoad F = (Cpe + Cpi) x q Perimeter 2.00 Perimeter 0.20 Perimeter 2.56 kNM2 Field 1.00 Field 0.20 Field 1.40 kNM2

Ridge 0.90 Ridge 0.20 Ridge 1.28 kNM2 v in mls 40.00 Statistical concep S3 1.00 K Perimeter = 15% of reservoir length/width Reservoir Details Perim Length (m) 159.00 Width (m) 55.00 Elevation 1.00 In accordance with the above criteria the calculated field area uplift force applied to the interior of the reservoir cover is of the order of 1.56 kNIM2. At the perimeter the 2 uplift force is of the order of 2.56 kN/m By way of an alternative to the anchoring or ballasting system of Figure 6, Figure 7 illustrates a short cylindrical tray 16 suspended beneath the cover. Unlike the preceding embodiment, this tray 16 is designed to resist uplift through the weight of the water trapped above the tray 16 and through ffictional resistance. The tray 16 acts as a drag element to provide dragging counteraction to any uplift.

A further alternative embodiment is illustrated in Figures 8 and 9 and comprises a ballast module 19 which is adapted to be mounted between adjacent panel units 10 and has lateral edges 20 that correspond to and overlap the lateral edges 9 of the panel units 10. It is secured to those panel units 10 by the same fastening means 1, 2 as used for fastening together the panel units 10.

The ballast module, or intermediate bridging unit, 19 is an elongate bladder having a pair of openings at each end of the top face thereof with each having a valve 21 a or 21 b for filling with water or other suitable fluid to increase the weight of the module or for venting the fluid to decrease the weight until the desired ballasting level is reached.

Turning, to Figure 10, this shows a yet further alternative embodiment of ballasting system where the panel unit 10 has itself been modified to receive ballasting fluid - in this case water from the reservoir - into its internal chamber to partially fill the chamber. The adaptation comprises an aperture 22 in the rising base wall of the panel unit 10 which has a removable plug 23 whereby upon placing the panel unit 10 upon the reservoir surface water may enter the unit 10 and fill it to a substantially predetermined level to achieve the desired balance of buoyancy with weighting down. If further desired the chamber to receive the ballasting fluid may be only part of the internal volume of the unit 10. A separating wall may, for example, be employed within the panel unit 10 to separate the water- filled chamber from an air-filled or insulating foam-filled chamber.

11

Claims

Claims

1. A floating cover for reservoirs or other large bodies of liquid, which cover comprises a plurality of panel units, each panel unit being fastened to each adjacent panel unit, directly or indirectly, by fastening means, said fastening means each comprising a male member and a female member, the male member having a head with a substantially straight and substantially rigid shank upstanding therefrom, the shank being provided with a plurality of teeth, the female member being a collar having a bore with mating teeth therein to co-operatively engage with the teeth of the male member to allow the shank of the male member to enter the bore of the 10 collar but prevent withdrawal.

is 2. A fastening means for fastening together a pair of panels or other structural elements, which fastening means comprises a male member and a female member, the male member having a head with a substantially straight and substantially rigid shank upstanding therefrom, the shank being provided with a plurality of teeth, the female member being a collar having a bore with mating teeth therein to cooperatively engage with the teeth of the male member to allow the shank of the male member to enter the bore of the collar but prevent withdrawal.

3. A method of assembling a floating cover for a reservoir or other large exposed body of liquid, which method comprises:

(i) providing a cover having a plurality of panel units which when linked together form the cover and providing fastening means to fasten together adjacent panel units, which fastening means comprise a male member and a female member, the male member having a head with a shank upstanding therefrom, the 12 shank being provided with a plurality of teeth, the female member being a collar having a bore with mating teeth therein to co-operatively engage with the teeth of the male member to allow the shank of the male member to enter the bore of the collar but prevent withdrawal; (5) offering up the male member of the fastening means to an edge of a panel with the shank of the male member passing up through an aperture in said edge; (iii) fitting a said female member over the shank of the male member to fasten the female member to the male member on the opposite face of the panel unit edge and with a portion of the shank of the male member protruding therefrom; (iv) offering the protruding part of the shank of the male member up through an aperture in an edge of an adjacent said panel unit; and (v) fastening a further said female member over the part of the shank of the male member protruding up through the edge of the further adjacent panel unit, thereby securing said panel to said adjacent panel.

4. A floating cover for reservoirs or other large expanses of exposed liquid, which cover comprises a plurality of panel units linked together in use with each neighbouring panel unit fastened to its neighbour, wherein the floating cover further comprises one or more anchoring means or ballasting means mounted to the floating cover.

5. A floating cover as claimed in Claim 4 wherein a weight is suspended beneath the cover via a pulley.

13 6. A floating cover as claimed in Claim 4 wherein one or more drag elements are suspended from the cover, in use, to provide drag by virtue of the upper surface area of the drag element, counteracting any uplift movement.

7. A floating cover as claimed in Claim 4 wherein the floating cover comprises at least one modular unit that is adapted to be filled with water or other ballasting fluid to a desired level.

8. A floating cover as claimed in Claim 7, wherein the modular unit is an intermediate bridging unit between the panel units.

9. A floating cover as claimed in Claim 7 wherein the modular unit is a said panel unit and the panel unit has an aperture therein to allow partial or complete filling of a chamber within the panel unit with ballasting fluid.

10. A floating cover as claimed in Claim 9 wherein the aperture is provided on the underside of the panel unit.

11. A floating cover as claimed in Claim 10 wherein a removable plug is provided to selectively plug the aperture.

12. A floating cover substantially as hereinbefore described with reference to any suitable combination of the accompanying drawings.

14 13. A panel unit or bridging unit for a floating cover substantially as hereinbefore described with reference to any suitable combination of the accompanying drawings.

14. A fastening means for fastening together a pair of panels or other structural elements substantially as hereinbefore described with reference to any suitable combination of the accompanying drawings.