Floating cover for a liquid storage reservoir

Abstract

.Iadd. A floating cover for a liquid storage reservoir to prevent contamination of the stored liquid. The cover includes a continuous sheet of flexible material overlying the liquid and attached to the upper periphery of the reservoir, the area of the sheet being greater than the area encompassed by the upper periphery of the reservoir. The cover further includes floats in the central portion to float it higher than the peripheral portion whereby the excess material in the peripheral portion forms a depending rainwater collection sump..Iaddend.

We claim: 
     
       1. A floating cover for a liquid storage reservoir wherein the level of the stored liquid varies, said cover comprising: a continuous sheet of flexible material impervious to and adapted to completely overlie the liquid in the storage reservoir in coextensive relationship to the reservoir periphery for attachment thereto, the area and flexibility of said sheet permitting formation of depending folds in said sheet;   a plurality of anchors adapted to rest upon the bottom of said reservoir;   a plurality of flexible lines connecting said anchors to various portions of said sheet to constrain said sheet against lateral movement over the surface of the stored liquid;   and flotation means on said sheet interiorly of the outer periphery thereof for supporting said sheet upon the surface of the stored liquid whereby said depending folds tend to define a sump section adjacent the outer periphery of said sheet, rain water tending to collect in said depending folds and force said folds deeper into the stored liquid as the volume of rain water increases.   
     
     
       2. In combination with a liquid storage reservoir wherein the level of the stored liquid varies, a floating cover comprising: a continous sheet of flexible material impervious to and adapted to completely overlie said liquid in coextensive relationship to the reservoir periphery, the area of said sheet being greater than the area of said reservoir at the upper extremity thereof whereby depending folds are formed in said sheet;   fastening means for securing the outer periphery of said sheet adjacent the reservoir periphery;   a plurality of sets of individually inflatable float units attached to said sheet in spaced relationship across said sheet interiorly of the outer periphery thereof for supporting said sheet upon the surface of the stored liquid whereby said depending folds form adjacent the outer periphery of said sheet and define a sump section, rain water tending to collect in said depending folds each said set of float units defining an unsupported area of said sheet therebetween;   and drain lines extending across said sheet and having inlet openings in communication with said sump section and with each said unsupported area, and further having a discharge portion adapted for connection to a pump, said float units being adapted for individual inflation whereby rain water tends to flow away from the more highly inflated ones of said float units and into said unsupported areas adjacent the less inflated ones of said float unit.   
     
     
       3. In conbination: a liquid storage reservoir having sloping side walls and a peripheral berm;   anchor means located about the periphery of said reservoir adjacent said berm and including fixed and movable portions constituting jaws, and further including means for urging said jaws closed;   a continuous sheet of flexible material impervious to and adapted to completely overlie the liquid in the storage reservoir in coextensive relationship to the reservoir berm, the area and flexibility of said sheet permitting formation of depending folds in said sheet, the peripheral edges of said sheet being disposed between said jaws and firmly held thereby in the closed position thereof;   a plurality of anchors adapted to rest upon the bottom of said reservoir;   a plurality of flexible lines connecting said anchors to various portions of said sheet to constrain said sheet against lateral movement over the surface of the stored liquid;   and flotation means on said sheet interiorly of the outer periphery thereof for supporting said sheet upon the surface of the stored liquid whereby said depending folds tend to define a sump section adjacent the outer periphery of said sheet, rain water tending to collect in said depending folds and force said folds deeper into the stored liquid as the volume of rain water increases.   
     
     
       4. In combination: a liquid storage reservoir having sloping side walls and a peripheral berm;   anchor means located about the periphery of said reservoir adjacent said berm and including fixed and movable portions constituting jaws, and further including means for urging said jaws closed, said anchor means mounting a plurality of cable mounts;   a continuous sheet of flexible material impervious to and adapted to completely overlie the liquid in the storage reservoir in coextensive relationship to the reservoir berm, the area and flexibility of said sheet permitting formation of depending folds in said sheet, the peripheral edges of said sheet being disposed between said jaws and firmly held thereby in the closed position thereof;   flotation means on said sheet interiorly of the outer periphery thereof for supporting said sheet upon the surface of the stored liquid whereby said depending folds tend to define a sump section adjacent the outer periphery of said sheet, rain water tending to collect in said depending folds and force said folds deeper into the stored liquid as the volume of rain water increases;   and a plurality of cables extending between said cable mounts and beneath said sheet in positions to support said sheet in the absence of liquid in said reservoir.   
     
     
       5. Apparatus for preventing contamination of the stored liquid in an open reservoir, comprising: a continuous sheet of flexible, relatively thin material impervious to and completely overlying said liquid in coextensive relationship to the periphery of said reservoir, the size of said sheet being greater than the area encompassed by the upper periphery of said reservoir;   anchor means securing the outer periphery of said sheet to the upper periphery of said reservoir in fluid-tight relationship therewith;   and float means on said sheet spaced inwardly from the upper periphery of said reservoir to raise and lower said sheet on the surface of said liquid as the level thereof varies, with said float means supporting the area of said sheet engaged by said float means at a higher elevation than the .Iadd.peripheral .Iaddend.portion of said sheet spaced outwardly of said float means and inwardly of said anchor means whereby said .Iadd.peripheral .Iaddend.portion forms a depending rainwater collection sump, .Iadd.said float means comprising a plurality of float units arranged across the central portion of said sheet bounded by said peripheral portion, at least some of said float units being spaced apart to define paths for rain water to flow from said central portion toward said peripheral portion, said peripheral portion being unsupported by said float means whereby said peripheral portion is adapted to sink below the level of said central portion of said sheet to form said sump. .Iaddend..Iadd. 6. Apparatus for preventing contamination of the stored liquid in an open reservoir, comprising:   a continuous sheet of flexible, relatively thin material impervious to and completely overlying said liquid in coextensive relationship to the periphery of said reservoir, the size of said sheet being greater than the area encompassed by the upper periphery of said reservoir;   anchor means securing the outer periphery of said sheet to the upper periphery of said reservoir in fluid-tight relationship therewith;   and float means on said sheet spaced inwardly from the upper periphery of said reservoir to raise and lower said sheet on the surface of said liquid as the level thereof varies, with said float means supporting the area of said sheet engaged by said float means at a higher elevation than the peripheral portion of said sheet spaced outwardly of said float means and inwardly of said anchor means whereby said peripheral portion forms a depending rainwater collection sump, said float means comprising a plurality of float units arranged in a pattern across the entire central portion of said sheet bounded by said peripheral portion, at least some of said float units being spaced apart to define paths for rain water to flow from said central portion toward said peripheral portion, said peripheral portion being unsupported by said float means whereby said peripheral portion is adapted to sink below the level of said central portion of said sheet to form said sump in response to the weight of rain water collecting on said peripheral portion. .Iaddend..Iadd. 7. Apparatus for preventing contamination of the stored liquid in an open reservoir, comprising:   a continuous sheet of flexible, relatively thin material impervious to and completely overlying said liquid in coextensive relationship to the periphery of said reservoir, the size of said sheet being greater than the area encompassed by the upper periphery of said reservoir;   anchor means securing the outer periphery of said sheet to the upper periphery of said reservoir in fluid-tight relationship therewith;   and float means on said sheet spaced inwardly from the upper periphery of said reservoir to raise and lower said sheet on the surface of said liquid as the level thereof varies, with said float means supporting the area of said sheet engaged by said float means at a higher elevation than the peripheral portion of said sheet spaced outwardly of said float means and inwardly of said anchor means whereby said peripheral portion forms a depending rainwater collection sump, said peripheral portion normally being empty of any liquid whereby it is adapted to receive and collect rain water and sink below the level of said central portion of said sheet to form said sump. .Iaddend..Iadd. 8. Apparatus for preventing contamination of the stored liquid in an open reservoir, comprising:   a continuous sheet of flexible, relatively thin material impervious to and completely overlying said liquid in coextensive relationship to the periphery of said reservoir, the size of said sheet being greater than the area encompassed by the upper periphery of said reservoir;   anchor means securing the outer periphery of said sheet to the upper periphery of said reservoir in fluid-tight relationship therewith;   and float means on said sheet spaced inwardly from the upper periphery of said reservoir to raise and lower said sheet on the surface of said liquid as the level thereof varies, with said float means supporting the area of said sheet engaged by said float means at a higher elevation than the peripheral portion of said sheet spaced outwardly of said float means and inwardly of said anchor means whereby said peripheral portion forms a depending rainwater collection sump, said float means comprising a plurality of elongated floats, arranged in a plurality of strings extending across the central portion of said sheet bounded by said peripheral portion, said strings being disposed in parallel, spaced relationship to one another, to define paths for rain water to flow from said central portion toward said peripheral portion, said peripheral portion being unsupported by said float means whereby said peripheral portion is adapted to sink below the level of said central portion of said sheet to form said sump. .Iadd. 9. Apparatus for preventing contamination of the stored liquid in an open reservoir, comprising:   a continuous sheet of flexible, relatively thin material impervious to and completely overlying said liquid in coextensive relationship to the periphery of said reservoir, the size of said sheet being greater than the area encompassed by the upper periphery of said reservoir;   anchor means securing the outer periphery of said sheet to the upper periphery of said reservoir in fluid-tight relationship therewith;   and float means on said sheet spaced inwardly from the upper periphery of said reservoir to raise and lower said sheet on the surface of said liquid as the level thereof varies, with said float means supporting the area of said sheet engaged by said float means at a higher elevation than the peripheral portion of said sheet spaced outwardly of said float means and inwardly of said anchor means whereby said peripheral portion forms a depending rainwater collection sump, said peripheral portion being unweighted and unsupported by said float means, whereby said peripheral portion is adapted to sink below the level of said central portion of said sheet to form said sump solely in response to the weight of rain water collecting on said peripheral portion. .Iadd. 10. Apparatus for preventing contamination of the stored liquid in an open reservoir, comprising:   a continuous sheet of flexible, relatively thin material impervious to and completely overlying said liquid in coextensive relationship to the periphery of said reservoir, the size of said sheet being greater than the area encompassed by the upper periphery of said reservoir;   anchor means securing the outer periphery of said sheet to the upper periphery of said reservoir in fluid-tight relationship therewith;   and float means on said sheet spaced inwardly from the upper periphery of said reservoir to raise and lower said sheet on the surface of said liquid as the level thereof varies, with said float means supporting the area of said sheet engaged by said float means at a higher elevation than the peripheral portion of said sheet spaced outwardly of said float means and inwardly of said anchor means whereby said peripheral portion forms a depending rainwater collection sump, said float means comprising a plurality of float units arranged in a pattern across the entire central portion of said sheet bounded by said peripheral portion, at least some of said float units being spaced apart to define paths for rain water to flow from said central portion toward said peripheral portion, said peripheral portion being unsupported by said float means and normally empty of any liquid whereby it is adapted to receive and collect rain water and sink below the level of said central portion of said sheet to form said sump, said peripheral portion being unweighted whereby only the weight of rain water collecting on said peripheral portion is operative to form said sump..Iaddend.