Electrical resistance fluid heating apparatus

Apparatus for heating a fluid medium, comprising a housing having a fluid inlet and a fluid outlet, a fluid inlet channel and a fluid outlet channel communicating respectively with said fluid inlet and said fluid outlet, said housing defining a central passage opening into an exterior housing surface, a heating cartridge resident in said housing central passage and defining with said housing successive first and second interior channels in communication respectively with said fluid inlet channel and said fluid outlet channel, an electrical resistance heating element supported by said cartridge and extending successively through said first and second interior channels and having a mechanically stressed portion bridging said first and second interior channels, and means electrically shunting said portion of said heating element to eliminate electrical current flow through said portion to lessen the likelihood of failure of said heating element.

Apparatus for heating a fluid medium, comprising an elongate housing having a fluid inlet fitting and a fluid outlet fitting disposed on a first housing surface, a fluid inlet channel and a fluid outlet channel communicating respectively with said fluid inlet fitting and said fluid outlet fitting and extending from said first housing surface in mutual parallelism, said housing defining a generally cylindrical central passage opening into a second housing surface longitudinally opposite from said first housing surface, a generally cylindrical heating cartridge resident in said housing central passage and defining with said housing successive first and second interior channels in communication respectively with said fluid inlet channel and said fluid outlet channel and extending in mutual parallelism therewith, an electrical resistance heating element supported by said cartridge and extending successively through said first and second interior channels and having a mechanically stressed portion bridging said first and second interior channels, and means electrically shunting said portion of said heating element to eliminate electrical current flow through said portion to lessen the likelihood of failure of said heating element.

Apparatus for heating a fluid medium, comprising a housing having a fluid inlet channel and a fluid outlet channel, said housing defining a central passage opening into an exterior housing surface, a heating cartridge resident in said housing central passage and having first and second terminals accessible at the exterior of said housing, an electrical resistance heating element supported by said cartridge interiorly of said housing and connected with said first and second terminals, said heating element including a convoluted portion distal from both said first and second terminals, and means for electrically shunting said portion of said heating element to eliminate electrical current flow through said portion to lessen the likelihood of failure of said heating element.