Combining at least one centrifugal compression stage and at least one positive displacement compression stage in an integrally geared compressor to allow for different types of compression based on a temperature or a volume of gas to be compressed by the integrally geared compressor.

A vacuum pump, vacuum pump arrangement and method are disclosed. The vacuum pump comprises: at least one rotor; and a stator, an inlet for receiving gas during operation; and an exhaust for exhausting the gas. The vacuum pump comprises a shaft extending through a centre of said pump and comprising a plate mounted on an end of the shaft towards the inlet. The vacuum pump comprises control circuitry configured to control an axial position of the plate, a change in axial position of the plate providing a change in inlet conductance of gas to the vacuum pump. The plate is mounted such that it extends beyond the inlet in at least some axial positions of the rotor such that the plate is not on the same side of the inlet as the stator.

A vacuum system includes a vacuum pump and an electric motor for driving the vacuum pump. A cooling arrangement cools the vacuum system. A control performs at least one of decreasing voltage and increasing frequency of a signal applied to the electric motor to decrease an amount of magnetic flux generated in the electric motor instead of decreasing the current applied to the electric motor to arrive at a desired torque generated by the electric motor in response to pumping requirements of the vacuum pump.

A vacuum pump system for evacuating at least five volumes comprising a turbomolecular pump and a forevacuum pump arranged to pump an output of the turbomolecular pump arrangement to atmosphere. The turbomolecular pump has at least five pumping stages separated by rotor blades. Not more than three pumping stages have pumping speeds in excess of of the highest pumping speed when under vacuum and/or a pumping port cross section in excess of of the highest pumping port cross section, and at least two pumping stages have pumping speeds less than of the highest pumping speed when under vacuum and/or a pumping port cross section of less than of the biggest pumping port cross section. The ratio of pressures between the pumping stage with the highest pressure and the pumping stage with the lowest pressure is at least 100000:1 when under vacuum.

A device for leak detection on a test specimen, comprising a mass spectrometer (12), an at least three-stage turbomolecular pump (14), the input stage (18) of which is connected to the mass spectrometer (12) and which has a first intermediate gas inlet arranged between the input pump stage and the intermediate pump stage (26) and a second intermediate gas inlet arranged between the intermediate pump stage (26) and the output pump stage (24), an at least two-stage booster pump, the input pump stage (46) of which can be connected to the test specimen to be examined and which has an intermediate gas outlet (54) arranged between the input pump stage (46) and the output pump stage (48) and a pre-vacuum pump (22) which is connected to the outlet (20) of the output pump stage (24) of the turbomolecular pump (14) and is configured to generate a pre-vacuum pressure of less than 50 mbar at the outlet (20) of the turbomolecular pump (14) and to evacuate it against atmospheric pressure, characterized in that the intermediate gas outlet (54) of the booster pump is connected in a gas-conducting manner to the first intermediate gas inlet (36) of the turbomolecular pump (14) via a first connecting branch (62), and in that the outlet of the output pump stage (48) of the booster pump is connected in a gas-conducting manner to the second intermediate gas inlet of the turbomolecular pump (14) via a second connecting branch (64).

A compressor including a gear system configured to be driven by a drive unit, a plurality of compression stages coupled to the gear system, wherein the plurality of compression stages includes at least one centrifugal compression stage and at least one positive displacement compression stage, is provided. Furthermore, an associated method is also provided.

Provided is a vacuum pump having a stator disc having a divided structure, in which gaps or misalignments that occur between connection surfaces at which the divided structure is connected are reduced. In a turbo-molecular pump according to this embodiment, a mating relationship between a stator disc and a stator member for alignment (center-alignment) is opposite from that of the related art. Specifically, in a structure in which a base and the stator disc are fitted together, center alignment (positioning/centering) is performed through a structure in which an outer peripheral surface of the stator disc is held (restrained from an outer side) by an inner peripheral surface of the base to be connected thereto. Further, the mating structure of the stator disc includes an integral component. Moreover, the mating position of a stator blade and the mating position of the stator disc having a Siegbahn structure are provided separately.

A vacuum pump system comprising a main vacuum pump that is connected to a chamber that is to be evacuated. An auxiliary pump is connected to an outlet of the main vacuum pump. Furthermore, a sealing gas supply device is connected to the main vacuum pump. The sealing gas supply device is switched on and off with the aid of a control device as a function of a predetermined control variable. Additionally, a method for controlling the vacuum pump system.

A vacuum pump that limits accumulation of deposits while providing a satisfactory permissible flow rate is obtained. The vacuum pump includes a rotor, a plurality of stator portions that are disposed facing the rotor and have a gas compression function, and a reference member 301 that is one of members stacked toward an inlet port 101 from a base portion 129 and serves as a reference in an axial direction for the plurality of stator portions. The plurality of stator portions are disposed downstream of the reference member 301 (the side corresponding to the outlet port 133).

A vacuum pump system for evacuating at least five volumes comprising a turbomolecular pump and a forevacuum pump arranged to pump an output of the turbomolecular pump arrangement to atmosphere. The turbomolecular pump has at least five pumping stages separated by rotor blades. Not more than three pumping stages have pumping speeds in excess of of the highest pumping speed when under vacuum and/or a pumping port cross section in excess of of the highest pumping port cross section, and at least two pumping stages have pumping speeds less than of the highest pumping speed when under vacuum and/or a pumping port cross section of less than of the biggest pumping port cross section. The ratio of pressures between the pumping stage with the highest pressure and the pumping stage with the lowest pressure is at least 100000:1 when under vacuum.