Rotary Piston Vacuum Pump Piston pumps are used for some large scale vacuum applications. These pumps have got a sliding sleeve by which the gas enters, then 
drawn right into a cylindrical chamber and exhausted by a rocking piston plunger. These pumps are extremely 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 prepared for corrosive and oxygen provider.
