Abstract: Pool covers embodying the invention are formed of a very dense mesh material which ensures substantially one hundred percent shade while allowing water to pass uniformly through the cover and which is adequately strong to support the weight of an adult. The pool cover is formed of plastic fibers which are interwoven to form a dense mesh which is then subjected to a pressure and heat cycle to ensure that the resultant material has the requisite properties for allowing water to pass through at a desired rate (e.g., 0.1 to 5 gallons per square foot per minute) while blocking light (e.g., 100% shade). Thus, a self-filtering safety pool cover is formed which allows for water to pass through uniformly across its surface while blocking sunlight.

Abstract: Pool covers embodying the invention are formed of a very dense mesh material which ensures substantially one hundred percent shade while allowing water to pass uniformly through the cover and which is adequately strong to support the weight of an adult. The pool cover is formed of plastic fibers which are interwoven to form a dense mesh which is then subjected to a pressure and heat cycle to ensure that the resultant material has the requisite properties for allowing water to pass through at a desired rate (e.g., 0.1 to 5 gallons per square foot per minute) while blocking light (e.g., 100% shade). Thus, a self-filtering safety pool cover is formed which allows for water to pass through uniformly across its surface while blocking sunlight.

Abstract: A pool cover includes, in a preferred embodiment, an array of openings through an otherwise impervious pool cover sheet. A pair of filter units overlies the openings and allows only filtered water from the pool cover to drain into an underlying pool of water. A first (bottom) of the filter units is fixedly attached to the impervious sheet and includes a screen member tautly stretched across the array of openings for sharing stress in the sheet in the vicinity of the openings, and also includes a micromesh filter layer overlying the screen member. The second of the filter units is removably attachable to the first unit, as by VELCRO fastenings, and includes a lower micromesh filter layer, for directly overlying the micromesh filter layer of the first unit, and a macromesh filter layer directly overlying the micromesh filter layer.

Abstract: A system for optimizing current density versus voltage across a device for electroplating recoverablesilver from expended photographic solutions by controlling voltage applied across the electrodes of the device as a controlled function of current flow through the device, current being sensed in terms of voltage across a resistance in series with the device, and that voltage, after comparison with reference voltages being employed to control a voltage regulator in the circuit between a source of dc voltage and the electrodes. The cathode of the device is a removable flexible stainless steel cylinder, and is contained in a cylindrical tank of larger diameter than that of the cathode. The anode is a hollow graphite cylinder on which pivots an arm bearing two stirring paddles which is rotated from interiorly of the anode by means of a magnetic clutch.