Rotary vane: Rotary vane pumps are comprised of a series of vanes that are mounted to a rotor that turns inside a cavity. As the vanes rotate, centrifugal force extends them from their person slots, forming compression cells that get larger to draw air in from the intake and smaller to drive air out the exhaust.
Articulated piston: An articulated piston commercial vacuum pump works in a manner similar to that of an automobile engine. As the piston moves downward inside the cylinder, air flow is used through the intake valve. During the piston’s upward stroke, the surroundings is permitted to flee via an exhaust valve. Two spring-backed piston rings are accustomed to seal the piston to the cylinder.
Screw: Rotary screw pumnps include two parallel rotary screws in the pump casing. The screws are synchronized to turn in opposing directions, which causes the compression actions to occur. The gas is definitely compressed in the direction of the pump’s discharge port.
Liquid ring: Liquid ring pumps also operate via positive displacement. During operation, the pump’s impeller rotates within the pump casing. A rotating liquid ring after that seals the impeller and its blades. Liquid can be sucked in to the compression chamber to keep carefully the ring steady. Conveyed gas is usually compressed during each impeller revolution.
Claw: Claw vacuum pumps consist of two rotors that are extremely close but usually do not are exposed to one 
another during rotation. As the rotors convert they actually enlarge the area between them to draw in air, then because they rotate around, actually Industrial Vacuum Pumps reduce the space between them to compress the surroundings out from the chamber.