Twin shaft rotary piston pump for simultaneously producing vacuum and excess pressure

摘要

The rotary piston pump has two rotary pistons (4) mounted on parallel shafts. The pump is single-stage and in addition to its inlet (6) on the suction side also has at least a further inlet opening (9) as connection from the atmosphere into the pump chamber at a point where the prevailing work pressure is less than the atmospheric or surrounding pressure outside the pump. During rotation of the rotary pistons (4) the additional inlet opening is screened and sealed from both the inlet at the suction side and from the outlet (7) on the pressure side.