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