Patent Number: 048440493
Section: abstract

A water heater device including an inner tank for containing water surrounded in spaced apart relationship by an outer shell. The top end of the water heater device is closed by a cap, and the bottom end of the water heater construction is closed by a floor connected to the outer shell. The inner tank has a concave bottom wall. A collar of thermal insulation material, such as fiber glass is located in the annular space between the inner tank and outer sleeve proximate the bottom end of the water heater device concentric with the annular space such that the collar is in contact with the interior wall surface of the outer shell, in contact with the exterior wall surface of the inner tank, and in contact with the floor of the water heater device. The collar has a radial thickness greater than the radial width of the annular space such that the collar is compressed between the interior wall surface of the outer shell and exterior wall surface of the inner tank sufficiently to tightly seal the interface of the collar and inner wall surface of the outer sleeve, and seal the interface of the collar and exterior wall surface of the inner tank. A disc of thermal insulation material, such as fiber glass, is located within the concavity of the bottom wall of the inner tank. Further, the annular space above the annular collar is filled with an expandable foam thermal insulation material.