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