A multi-stage vacuum pump comprising a stator defining multiple pumping chambers is discussed. The stator comprises a plurality of transfer channels for providing a fluid passage from an outlet port of one of the plurality of pumping chambers to an inlet port of a subsequent pumping chamber. Some of the transfer channels comprise two side channel sections on opposing sides of the stator. One of the transfer channels comprises a single side channel section on one side of the stator. The vacuum pump further comprises a gas ballast inlet channel arranged on an other side of the stator to the one side of the stator.

A scroll pump has a tip seal between an axial end of the scroll blade of one of stationary and orbiting plate scrolls of the pump and the plate of the other of the stationary plate and orbiting plate scrolls. The scroll pump may have a ballast gas supply system and use the operation of the ballast gas supply system to assess the condition of the tip seal. Alternatively, the scroll pump may have two pressure sensors that sense pressure at two locations spaced along a compression mechanism of the pump to assess the condition of the tip seal.

A production apparatus for a liquid containing gas bubbles includes a casing, a pump unit, and a gas bubble-mixing unit. The casing is provided with a main flow channel for a liquid, the main flow channel having a liquid inflow port and a liquid outflow port. The pump unit is disposed in the main flow channel and pumps the liquid to the liquid outflow port from the liquid inflow port. The gas bubble-mixing unit includes a first choke portion that is disposed in the main flow channel and has an inner diameter decreased and a gas supply channel that supplies the first choke portion with a gas.

A vacuum pump is provided that includes rotor elements arranged in a suction chamber. An outlet duct is connected to an exhaust pipe. For the purpose of silencing, sound expansion spaces are provided in the outlet duct, which are integrated into the pump housing. Alternatively or in addition to these sound expansion spaces, sound expansion spaces may be provided in an inlet duct which is used for the inlet of gas ballast, said sound expansion spaces being preferably likewise integrated into the pump housing.

A rotary piston compressor/pump/blower includes a housing spatially limiting a working chamber, an intake connection for guiding fluid into the working chamber, a pressure connection for guiding the fluid out of the working chamber, and a rotor assembly having a first rotor rotatably arranged in a first working sub-chamber and a second rotor cooperating with the first rotor and rotatably arranged in a second working sub-chamber. The rotary piston compressor/pump/blower also includes a ventilation channel, formed in the housing and connected to the working chamber via a ventilation channel opening, for the temporally limited introducing of air into the working chamber, wherein the ventilation channel opening is open at least in sections, in particular completely open, in a compression phase.

A multi-stage vacuum pump comprising a stator defining multiple pumping chambers is discussed. The stator comprises a plurality of transfer channels for providing a fluid passage from an outlet port of one of the plurality of pumping chambers to an inlet port of a subsequent pumping chamber. Some of the transfer channels comprise two side channel sections on opposing sides of the stator. One of the transfer channels comprises a single side channel section on one side of the stator. The vacuum pump further comprises a gas ballast inlet channel arranged on an other side of the stator to the one side of the stator.

A rotary piston compressor/pump/blower includes a housing spatially limiting a working chamber, an intake connection for guiding fluid into the working chamber, a pressure connection for guiding the fluid out of the working chamber, and a rotor assembly having a first rotor rotatably arranged in a first working sub-chamber and a second rotor cooperating with the first rotor and rotatably arranged in a second working sub-chamber. The rotary piston compressor/pump/blower also includes a ventilation channel, formed in the housing and connected to the working chamber via a ventilation channel opening, for the temporally limited introducing of air into the working chamber, wherein the ventilation channel opening is open at least in sections, in particular completely open, in a compression phase.

A vacuum pump comprises rotor elements arranged in a suction chamber. An outlet duct is connected to an exhaust pipe. For the purpose of silencing, sound expansion spaces are provided in the outlet duct, which are integrated into the pump housing. Alternatively or in addition to these sound expansion spaces, sound expansion spaces may be provided in an inlet duct which is used for the inlet of gas ballast, said sound expansion spaces being preferably likewise integrated into the pump housing.

A rotary piston engine comprises a housing (1) spatially limiting a working chamber (2), an intake connection (4) for guiding gas into the working chamber (2), a pressure connection (6) for guiding the gas out of the working chamber (2), and a rotor assembly (4) having a first rotor (14) rotatably arranged in a first working sub-chamber (12) and a second rotor (21) cooperating with the first rotor (14) and rotatably arranged in a second working sub-chamber (13). The rotary piston engine also comprises a ventilation channel (8), formed in the housing (1) and connected to the working chamber (2) via a ventilation channel opening (9), for the temporally limited introducing of air into the working chamber (2), wherein the ventilation channel opening (9) is open at least in sections, in particular completely open, in a compression phase.

A vacuum pump system includes an air-cooled, O-ring sealed vacuum pump and an oil management system with an LED illuminated clear tank for observation of the oil condition as well as a large oil inlet and outlet for rapid and safe oil changes while the pump is operating. The oil management system is also configured to prevent oil from the sump from being drawn into an evacuated AC/R system when the pump is stopped and the intake ports are not sealed from the high vacuum AC/R system. The oil management system includes a preferential vacuum relief system that allows air instead of the oil from the sump to be drawn back into the evacuated lines.