this device for inductively heating and fusing thermoplastics includes an alternating current passing through a tank circuit , the inductor member of the tank circuit being wrapped around a curved pole piece of a ferromagnetic material . the magnetic flux arising within the inductor coil member flows to the ends of the pole piece and into a screen placed between the materials to be joined . the flux induces a current in the screen , and heat is generated to melt the thermoplastics together . because only 30 - 150 watts of power are passed through the tank circuit , a wire which will remain cool under operational wattage may be selected , making air or fluid cooling unnecessary .