Piston pumps are used for some large level vacuum applications. These pumps have a sliding sleeve by which the gas enters, after that drawn right into a cylindrical chamber and Rotary Piston Vacuum Pump exhausted by a rocking piston plunger. These pumps are very hardy and have pumping 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 services.