Mechanical booster pumps (a.k.a. "Roots Blowers") can be used on the inlet of primary roughing pumps, such as oil-sealed rotary vane pumps, dry pumps, scroll pumps or water ring backing pumps to improve the pumping speed in the 75 Torr to 75mTorr pressure range, where pumping speeds of roughing pumps often falls off dramatically. The PRC-A roots type pump series is designed for general purpose, semiconductor and liquid crystal display processes which require extreme cleanliness of the pump, both inside and out. The PMB-040C & 060C models are well suited for the large volume evacuation required by vacuum heating and vacuum melting furnaces, and other large volume pumpdown work such as space simulation chambers