Electrically heated multi-section hose having electrically heated hose

Abstract

A hot melt hose has multiple electrically heated hose sections physically and electrically interconnected end-to-end between a pressurized hot melt source and hot melt dispenser, such as a hand-held gun having a trigger-controlled valve for regulating the flow of hot melt from the gun. Each of the hose sections includes an inner, fluid impervious, chemically inert tube, preferably fabricated of tetrafuoroethlene; an electrically conductive multi-strand braided resistance heating sheath snugly embracing the exterior surface of the inner tube and in intimate heat transfer contact therewith for supplying strength and heat to the tube; and an outer sheath of thermal insulating material for minimizing heat loss. The hose sections are interconnected by a heated joint which comprises electrically conductive hose end fittings electrically connected to the braided sheath and connected by threaded swivel nuts to an electrical insulating fitting. Internally of the insulating fitting there is an electrical resistance heater spring which extends between and electrically interconnects the hose end fittings. The spring has an electrical resistance such that the flow of current from the braided sheath of one hose section to that of the other produces sufficient heat in the fitting so that the interior of the joint is maintained at approximately the same temperature as the interior of the hose sections.