a gear - type pump for thermoplastic materials including synthetic and natural polymers or resins , the pump including a housing , intermeshing gears disposed in the housing , the housing having an inlet conduit for directing bulk thermoplastic materials to the gears and an outlet conduit for movement of the material from the gears , and heater structure disposed in the housing and proximate the gears and the inlet and outlet conduits to impart heat to the material as the material flows through the pump .