Abstract Tubular electrical resistance heater having a flexible heater element composed of a core with a resistance wire wound helically around the core and integral unheated terminal portions. The heater element is disposed in an open ended metallic tube with its unheated portions extending from within to without the tube where a lead wire is connected to the ends of the unheated terminal portions. A conductive ground wire is in electrical contact with the outer surface of said tube at a location corresponding to the unheated terminal portions of the heater element. A unitary moisture impervious sealing material encapsulates the end of the tube, the connection of the heater to the lead wire and the connection of the ground wire to the tube.
Tubular electrical resistance heater comprising a hollow aluminum tube, open at at least one end, an insulated resistance heater disposed in said tube and having nonheating terminal sections extending from within to without said open end, an insulated lead conductor wire connected to the unheated terminal section outwardly of the tube, an insulated ground wire having a copper conductor with a bare end portion, a conductive metal band clampingly retaining said bare end portion in electrical contact with the surface of said metal tube adjacent said open end and at a location on said tube in axial correspondence with a nonheating terminal section, said ground conductor and tube being dissimilar metals, and a unitary, moisture impervious elastomeric material encapsulating the open end of said tube, the connection to said lead conductor wire and the portion of the ground conductor in contact with said tube, said nonheating terminal section extending inwardly beyond the inner end of the encapsulating material.
Claim 2
Dependent Claim
158 words
Tubular electrical resistance heater comprising a hollow aluminum tube, open at at least one end, an insulated resistance heater disposed in said tube and having nonheating terminal sections extending from within to without said open end, an insulated lead conductor wire connected to the unheated terminal section outwardly of the tube, an insulated ground wire having a copper conductor with a bare end portion, a conductive metal band clampingly retaining said bare end portion in electrical contact with the surface of said metal tube adjacent said open end and at a location on said tube in axial correspondence with a nonheating terminal section, said ground conductor and tube being dissimilar metals, and a unitary, moisture impervious elastomeric material encapsulating the open end of said tube, the connection to said lead conductor wire and the portion of the ground conductor in contact with said tube, said nonheating terminal section extending inwardly beyond the inner end of the encapsulating material.
Claim 3
Dependent Claim
112 words
Tubular electrical resistance heater as set forth in claim 1 in which said ground conductor and lead conductor extend in generally parallel relationship from the encapsulating elastomeric material, said lead wire being connected to the outer end of the nonheating terminal section by means of a metallic, electrically conductive connector, said grounding band comprising a generally split sleeve band composed at least in part of copper, fitted in clamping engagement about said tube adjacent an open end thereof, said band having axially spaced circumferentially extending slots, said conductor of the ground wire threaded through said slots whereby the ground conductor is held in intimate electrical and firm mechanical engagement with said tube.