Multi-section roots vacuum pump of reverse flow cooling type with internal flow division arrangement

Abstract From the Canadian patent

A multi-section Roots vacuum pump of the reverse flow cooling type with internal flow division arrangement includes a sequence of pump sections, casings for the pump sections including housings for accommodating pairs of rotor therein, inlet passages and outlet passages connected to the casing for pump sections upper peri-, pheral gas passages connected to the inlet passage formed around an upper portion of the housing lower, peripheral gas passages connected to a supply inlet of reverse flow cooling gas formed around a lower portion of the housing, partition walls between the upper and lower peripheral gas passages, and inter-section walls for separating adjacent pump sections. …