A vacuum pump suitable for mounting to an engine includes: a casing having a cavity, the cavity including an inlet and an outlet; a moveable member arranged for rotation inside the cavity, the movable member being movable to draw fluid into the cavity through the inlet and out of the cavity through the outlet so as to induce a reduction in pressure at the inlet; a valve seat at the outlet; and an outlet valve including a reed element and a stop for restricting movement of the reed element. The stop is movable between a first operating position, in which movement of the reed element is restricted to a first opening degree, and a second start-up position, in which movement of the reed element is restricted to a second opening degree, which is larger than the first opening degree.

A pump apparatus which can more accurately determine the occurrence of an abnormal vibration. The pump apparatus includes: a pump; an electric motor for driving the pump; an inverter as a speed changing means for the electric motor; a vibration detector for detecting at least one of a vibration of the pump, a vibration of the electric motor and a vibration of the inverter; and a controller for controlling the pump. The controller includes a storage unit for storing a measured vibration value measured by the vibration detector. The storage unit has a storage table which, when the rotational speed of the pump is increased stepwise to a predetermined rotational speed, stores the measured vibration value measured at each step.

Dual- or multi-shaft vacuum pump comprising an engine, a first shaft and at least one second shaft, wherein the first shaft and the second shaft are synchronously driven by the motor via a common drive belt. The first shaft has a pumping element and the second shaft likewise has a pumping element which cooperates with the pumping element of the first shaft in order to convey a gaseous medium from an inlet to an outlet. The first shaft has a first emergency running gear and the second shaft likewise has a second emergency running gear which meshes with the first emergency running gear.

A pump cooling system may include a cooling body configured to be fitted to a pump housing to receive heat from the pump housing via a heat conducting path between the cooling body and pump housing. The cooling body may have a passage through which, in use, a cooling fluid is passed to conduct heat away from the cooling body. The pump cooling system includes a cooling control mechanism configured to provide a gap in the heat conducting path at pump operating temperatures below a predefined temperature so heat conduction from the pump housing to the cooling body is interrupted.

An automotive auxiliary assembly vacuum pump includes a housing composite structure with an electric motor section, a pump section, a pump inlet opening, and a pump outlet opening, a motor housing part, a bearing plate which closes the motor housing part proximally, and a pump rotor with a rotor body. The electric motor section includes a motor rotor which is surrounded by the motor housing part and which is closed by the bearing plate. The pump section includes a pump housing which defines a pump chamber and which includes a closure element, at least one pump chamber inlet opening, and at least one pump chamber outlet opening. The pump housing is formed at least by axially proximal and axially distal thrust washers and a radial thrust ring. Only the bearing plate and the axially proximal thrust washer are provided as a single-piece flange element.

A pumping unit is provided, including a primary vacuum pump of a multistage dry type, including at least four pumping stages fitted in series; and a two-stage Roots vacuum pump, including a first pumping stage and a second pumping stage fitted in series, the second pumping stage being fitted in series with and upstream of a first pumping stage of the primary vacuum pump in a direction of flow of gases to be pumped, in which a ratio of a volume displacement of the first pumping stage of the two-stage Roots vacuum pump to a volume displacement of the second pumping stage of the two-stage Roots vacuum pump is less than six, and in which a ratio of a volume displacement of the second pumping stage of the two-stage Roots vacuum pump to a volume displacement of the first pumping stage of the primary vacuum pump is less than six.

A motor vehicle vacuum pump includes a pumping chamber in which a pump rotor rotates to compress a gas, an outlet chamber into which the gas exits, a separation wall which includes a valve opening and a valve seat arranged on an outlet side of the separation wall around the valve opening. The separation wall separates the pumping chamber from the outlet chamber. An outlet valve is formed as a non-return valve in the separation wall. The outlet valve is formed by the valve opening in the separation wall and includes a valve body with a closing body. The outlet valve has the gas exit therethrough from the pumping chamber into the outlet chamber. A corresponding part of the closing body is supported on the valve seat when the closing body is in a closed position. The valve seat and/or the corresponding part of the closing body includes microgrooves.

A pump and method for pumping a gas are disclosed. The pump comprises a rotor and a stator. At least one of the rotor or stator comprises at least one liquid opening configured for fluid communication with a liquid source. The liquid opening is configured such that in response to a driving force exerted on liquid from the liquid source a stream of liquid is output from the opening, the stream of liquid forming a liquid blade between the rotor and the stator, gas confined by said stator, said rotor and said liquid blade being driven through said pump from a gas inlet towards a gas outlet.

A multi-stage rotary piston pump comprising two shafts in a housing, which support multiple rotary pistons. Corresponding rotary pistons form a respective rotary piston pair, wherein multiple rotary piston pairs are provided which form a respective pump stage. Neighboring pump stages are each connected to one another via connection channels. The multi-stage rotary piston pump also comprises a pump inlet that is connected to the first pump stage, as well as a pump outlet that is connected to the last pump stage. The built-in volume ratio is at least 15, so that high pumping capacities of at least 1500 m.sup.3/h can be achieved.

The invention relates to a scroll pump comprising a pressure sensor integrated into the scroll pump.