Metal sheath heating element and method of manufacturing same

Abstract

A metal sheath heating element for substantially dry applications is disclosed. In one embodiment, the heater is substantially elongate and cylindrical, and comprises a coiled resistive heater wire. The heater wire is disposed within a stainless steel outer sheath. Granular insulating material is introduced into the sheath to electrically insulate the heating element from the outer sheath, and to thermally conduct heat from the heating element to the sheath. At least one small hole is formed in outer sheath to permit any moisture trapped therein to escape, advantageously minimizing the potential for current leakage between the heating element and the outer sheath, as well as minimizing the likelihood of depletion of oxygen from the filler material due to oxidation occurring within the sheath. In one embodiment, a plurality of holes are formed at spaced intervals along the length of the sheath.

Dependencies are inferred from the claim text.