Rotary piston pump has many types of structures, among which the most commonly used one is Cam pump, Roots pump, etc.

The cam pump is a multi-purpose two-way positive displacement pump and one of the most advanced fluid conveying equipment in the world. It uses two synchronously moving rotors. The rotors are driven by a pair of external synchronous gears. The rotors are driven by the transmission shaft. It performs synchronous reverse rotation, and the rotors and the rotor and the pump body do not contact each other, but form a gap line or surface seal, thus forming a higher vacuum degree and discharge pressure, which is especially suitable for food, medicine, corrosive and Conveying of high viscosity media.

Roots pumps are similar in structure to cam pumps. The difference is that the liquid seal must also be formed between the rotors. Large pumps are mostly simply supported. Its processing is simpler than that of cam pumps, and its working pressure is lower than that of cam pumps.