Heat-treatment apparatus for synthetic fiber yarns

Claim 1

A heat-treatment apparatus for synthetic fiber yarns including a vertically elongated sealed vessel having its one side wall cOnstructed of a heat-exchanging wall with a heating surface for said yarns formed on its outside and forming a thermal medium vapor chamber inside of said sealed vessel; comprising A. an electric heater including an upright metallic tube closed at its lower end, an electric resistance element within said tube and electrically insulated therefrom; and a cover attached to the outer surface of said tube and covering substantially the whole surface thereof, said cover being a heat-resistive and mesh-type porous material having a porosity such that capillarity may occur therein for a given liquid thermal medium, the lower end portion of the heater being submerged in said liquid thermal medium enclosed at the bottom of said vertically elongated sealed vessel with most of the remainder thereof exposed in said thermal medium vapor chamber, B. a return liquid thermal medium guide plate attached to and disposed between the inner surface of said heat-exchanging wall and the portion of said electric heater exposed in the thermal medium vapor chamber. C. a separator tank communicated with the upper portion of said vertically elongated sealed vessel, and D. a return pipe having its upper end communicated with said separator tank, and having its lower end disposed within said sealed vessel at a position just above said electric heater.