Device for heating liquid in a container

Claim 1

A flexible heating cable assembly for immersion heating of a liquid in a container, said cable comprising: (a) a heating element disposed in coiled, axially spaced internally unsupported pitches of substantially uniform diameter having a length substantially greater than the coil diameter, said element being formed of bare wire having a high electrical resistance; (b) a flexible braided sheath of fibrous glass material received over said coiled pitches along the length thereof, said sheath having the inner periphery thereof disposed in closely fitting arrangement with the outer diameter of said coiled pitches and in direct free sliding contact therewith; (c) an outer tubular casing formed of resilient electrical insulating material having a low surface coefficient of friction and a high resistance to heat and attacks by acid and alkaline solutions, said casing being received over said sheathed coiled element and in direct free sliding contact with said braided sheath along the length thereof; (d) connecting means attached to each end of said coiled element and disposed within said casing; (e) power lead means attached to each of said connectors, said lead means extending beyond the respective adjacent end of said casing, said lead means being adapted for connection to a source of electrical power; and (f) said braided sheath being sized such that upon flexing of said cable assembly, deformation, axial contact and collapse of said coiled pitches of said element are resisted by tensioning of the braid of the sheath.