WATER HEATER WITH PLASTIC STORAGE TANK MADE FROM CONCENTRIC TABULAR SHELLS AND INTEGRAL RIBS IN BETWEEN

An electric water heater has a body structure formed in a manner eliminating the need for a separate metal water storage tank therein. The body structure is formed from a coaxially and sealingly joined series of one-piece molded plastic body sections including opposite end sections having closed outer ends. Each one piece molded plastic body section has tubular inner and outer shell portions that are coaxial with one another and radially separated by a circumferentially spaced series of radially extending ribs molded integrally therewith and defining therebetween a circumferentially extending series of arcuate insulation spaces. In the assembled body structure the inner shell portions entirely define in the water heater an internal water storage vessel portion that is outwardly enveloped by the insulation spaces and structurally reinforced, via the integral ribs, by the outer shell sections. Suitable inlet and outlet piping is operatively communicated with the interior of the body structure, and water disposed in the internal storage vessel portion thereof may be selectively heated by one or more electric resistance type heating elements operatively mounted on the water heater body structure.