US Patent 7360639 Hot rotary screw pump

A screw feeder can be used to transport a high temperature particulate material. A housing contains the material within the screw feeder which includes an inlet and an outlet port. A screw is rotatably positioned within the housing to advance the material from the inlet port to the outlet port, which rotates axially. A labyrinth seal can be formed around and in communication with the screw to eliminate reverse movement of the material. A cooling medium can be directed into contact with at least the housing. A fluid can be injected through the screw to prevent blockage of the particulate material. A pressure differential is created from the inlet to the outlet port of at least 0.069 MPad.