... , sole pump, etc. When the 2 simultaneous reverse rotating rotors (with 2-4 gears) revolve, it produces suction force at the ... it revolves to position a, only housing I is filled with medium;when it revolves to position b, housing B encloses ... , medium (material) is transpor-ted continuously. Welcome to contact us for more information Screw pump,High Quality Pump,Delivery Pump ...