Swimming pool cover

Abstract

A thermally insulative buoyant swimming pool cover floats on the surface of the pool for covering the pool and for retaining the heat within the pool. Sinking means, such as weights or a mechanical pull-down structure, may be secured to the pool cover along certain predetermined action lines such as fold lines. In one embodiment, an inflatable and deflatable bladder is coupled to the weights. The bladder is dimensioned relative to the weights such that when inflated it overcomes the negative buoyancy of the weights to retain the pool cover in the fully covered position. However, when the bladder is deflated, the weights overcome the positive buoyancy of the cover along the certain fold lines causing the cover to be at least partially pulled below the surface of the pool and folded while at the same time being retracted against one of the side walls of the pool. Pool water is circulated over or through channels of the pool cover to provide solar heating. Pool water is circulated over the top of the cover for cleaning thereof. The weights, in one embodiment, are hollow to receive the inflatable bladders. Air permeable structures are contained within the bladders to obtain more uniform inflation thereof. The lip of the cover contains additional positive buoyancy for additional support at the lip. In an alternative embodiment, air and water are fed into a container or conduit portion of the cover, the ratio by volume of air to water is changed for switching the cover between a pool covering and a pool uncovering state. Air is injected via a venturi into the pool return line which is connected to the cover. The air and water mixture is fed through solar heating channels of the cover for solar heating of the pool water.