Abstract: An open coil electric heater comprising a rigid support frame composed of a pair of longitudinally extending, laterally spaced members, with cross members between and secured to the longitudinal members. The cross members carry ceramic coil supports which are detachably connected to the cross members. Each coil support has an end formed with a cross slot to pass a part of a convolution of a coil and hook-like projections are formed on opposite sides of a coil support and are cooperable with the coil convolution part to detachably hold the same to the coil support. The heating coil is secured to the coil supports in expeditious manner and without the use of tools by twisting the coil so that said convolution part is aligned sufficiently with said cross slot to enable said part to be seated within said slot. The coil is then permitted to spring back so that the convolution fits against opposite side faces of said coil support and held in position by said hook-like projections.

Abstract: Our invention relates to open coil electric heating elements of conventional construction but treated to resist corrosion and to electrically insulate exposed metallic surfaces. In accordance with the invention, the component parts of the heater, except the coiled resistance wire and in some cases the supporting insulating bushings, are assembled and then coated with a silicone resin-based coating composition. The composition is applied in a flowable state to cover all exposed surfaces and fill all cracks and crevices to thereby prevent accumulation of moisture thereat.