Piston pumps are used for most large level vacuum applications. These pumps have a sliding sleeve through which the gas enters, then drawn into a cylindrical chamber and exhausted by a rocking piston plunger. These pumps are extremely hardy and also have pumping speeds that range Rotary Piston Vacuum Pump china between 15 cfm to 2,000 cfm and the pumps can reach a pressure of just one 1 x 10-4 Torr. Rotary piston pumps could be prepared for corrosive and oxygen assistance.