Circumferential Piston Pump

A circumferential piston pump (also called an external circumferential piston pump) is a type of rotary positive displacement pump that uses two rotors mounted on separate shafts. These rotors are externally timed so they never touch each other as they turn. The most common rotor style is a bi-wing design. In operation, the rotors trap and carry fluid around the inside of the pump casing, creating flow in a manner similar to, but distinct from, a lobe pump.

1. What is a circumferential piston pump?
It’s a rotary positive displacement pump with a pair of independently driven, externally timed, non-contacting rotors that trap and move fluid through the pump housing.

2. How does a circumferential piston pump work?
As the rotors turn, they form cavities at the inlet that draw liquid into the spaces between the rotor tips. The fluid is carried around the pump casing inside these cavities and then forced out the discharge as the cavities shrink — all without the rotors contacting each other.

3. What are circumferential piston pumps used for?
Because they have large fluid-carrying cavities and a non-contacting design, these pumps are well suited for handling both thin and viscous liquids as well as liquids containing solids. They also lend themselves to sanitary, easily cleaned applications where frequent cleaning is required.