Electrically heated hose for heating melted adhesive and atomizing air fed to a spraying head

Claim 1

A hose for feeding a melted adhesive from an adhesive-liquifying device to an adhesive-spraying head, comprising a flexible tubular central core made of plastic for feeding an adhesive therethrough; a helical electric heating tape provided on the exterior of said core, said heating tape being helically wrapped around said core so that said tape has adjacent turns spaced from each other; an outer layer of thermal insulation surrounding said heating tape and said central core, said layer of thermal insulation being radially spaced from said central core to form a ring-shaped space therebetween, said heating tape being disposed in said space; an inlet end for connection to the adhesive-liquifying device; an outlet end for connection with the adhesive-spraying head, said hose being provided with an air passage disposed in heat-transmitting relation with said heating tape, said air passage being defined between surfaces of said helically wrapped heating tape, said core and an inner surface of said outer layer whereby said passage extends about said core over a helical path; air-admitting means provided on the hose in the region of said inlet end and connected to said passage; and air-discharging means provided on the hose in the region of said outlet end and connected to said passage, whereby air entering said air-admitting means is heated while flowing through said passage and enters the adhesive-spraying head via said air-discharging means in pre-heated condition to atomize an adhesive sprayed out from the adhesive-spraying head.