Sheathed electric heating unit

Claim 1

A SHEATHED HEATING UNIT COMPRISING: (A) AN ELECTRICALLY CONDUCTIVE SHEATH HAVING A CLOSED END, (B) A HEATING ELEMENT OF GENERALLY HOLLOW OPEN-ENDED FORM SUBSTANTIALLY CENTRALLY SPACED FROM THE INNER WALL OF SAID SHEATH AND ELECTRICALLY CONNECTED TO SAID CLOSED END OF SAID SHEATH, (C) INSULATING MATERIAL INCLUDING AT LEAST ONE COMPRESSED TUBULAR FRANGIBLE MEMBER, SAID TUBULAR FRANGIBLE MEMBER POSITIONED PRIOR TO COMPRESSION BETWEEN THE INNER WALL OF SAID SHEATH AND THE OTHER SURFACE OF SAID HEATING ELEMENT TO MAINTAIN SAID HEATING ELEMENT WITH RESPECT TO SAID SHEATH, SAID INSULTING MATERIAL ALSO INCLUDING GRANULAR INSULATING WITHIN THE INTERIOR OF SAID HEATING ELEMENT, AND (D) A CYLINDRICAL, SUBSTANTIALLY SOLID TERMINAL HAVING ONE END ELECTRICALLY CONNECTED TO SAID HEATING ELEMENT AND BEING RELATIVELY CENTRALLY DISPOSED IN SAID SHEATH, SAID TERMINAL HAVING A SLOTTED DUCT FORMED IN SAID ONE END WHICH COMMUNICATES WITH THE INTERIOR OF SAID HEATING ELEMENT DURING MANUFACTURE, WHEREBY SAID GRANULAR INSULATION MAY BE INTRODUCED INTO THE INTERIOR OF SAID HEATING ELEMENT.