Film-type solar water heater

Claim 1

A SOLAR WATER HEATER OF THE CHARACTER DESCRIBED, COMPRISING A RIGID, PLANAR, BACKING SHEET HAVING ONE SURFACE THEREOF PAINTED A DARK, HEAT-ABSORBING COLOR, SAID BACKING SHEET BEING SUPPORTED IN AN INCLINED POSITION WITH RESPECT TO THE HORIZONTAL SO AS TO BE EXPOSED TO THE SUN, A WATER INLET TUBE MOUNTED IN THE VICINITY OF THE UPPER END OF THE BACKING SHEET, SAID TUBE INCLUDING MEANS FOR DISCHARGING A STREAM OF WATER TRANSVERSELY ALONG THE BACKING SHEET, A WATER COLLECTING HEADER MOUNTED ON THE LOWER END PORTION OF SAID BACKING SHEET, MEANS FOR INTRODUCING WATER INTO THE INLET TUBE TO PROVIDE A GRAVITATIONAL FLOW OF WATER OF CAPILLARLY THICKNESS DOWN THE SURFACES OF THE INCLINED BACKING SHEET, A THIN PLIABLE PLASTIC FILM OVERLYING THE WATER CONTACTING SURFACE OF THE BACKING SHEET, ONE END OF THE PLASTIC FILM BEING SECURED TO THE WATER INLET TUBE AND THE OPPOSITE END OF THE PLASTIC FILM BEING SECURED TO THE COLLECTING HEADER, THE LATERAL EDGES OF THE PLASTIC FILM BEING FREE FROM CONNECTION TO THE BACKING SHEET, AND MEANS OPERATIVELY CONNECTED TO THE BACKING SHEET FOR MAINTAINING THE PLIABLE PLASTIC FILM CLOSELY ADJACENT AND PARALLEL TO THE WATER CONTACTING SURFACE OF THE BACKING SHEET, WHEREBY THE SURFACE TENSION OF THE THIN FILM OF WATER FLOWING GRAVITATIONALLY DOWNWARDLY OF THE BACKING SHEET DRAWS THE PLASTIC FILM IN THE DIRECTION OF THE WATER CONTACTING SURFACE OF THE BACKING SHEET, THEREBY CAUSING THE WATER FLOWING DOWNWARDLY THEREON TO SPREAD INTO A THIN, UNIFORM LAYER COVERING SUBSTANTIALLY THE ENTIRE AREA OF THE BACKING SHEET.