Abstract: The invention relates to a cryopump having a casing (1), a gas inlet opening (8) to which a chamber (30) can be attached through a valve (31), a vacuum pump (18) connected through a valve (16) to the casing, a two-stage refrigerator (4) in the casing as cold source, and pumping surfaces (7, 9, 12, 13) which, on both of the refrigeration stages (5, 11) of the refrigerator, are equipped with an electrical heating means (23, 24). To achieve a great shortening of the time required for regeneration and start-up it is proposed that a sensor (41) be provided to monitor the pressure within the pump casing, and that a control unit (28) be present by which the operation of the cryopump can be monitored and controlled on the basis of the signals supplied by the sensor.

Abstract: A refrigerating machine having a displacer reciprocable in a hollow space having a substantially-closed end for the refrigerating operation has a spring between the displacer and the substantially-closed end of the hollow space for damping vibration and noise of the displacer reciprocation.

Abstract: A cryopump has a two-stage refrigerator in a housing with a pumping surface area in thermal communication with each stage of the refrigerator for gas-pumping by adsorption or absorption when the refrigerator is operated. A roughing vacuum pump provides a pressure of from about 1 to about 10.sup.-3 mbar to the housing and at least the pumping surface area of the second refrigerator stage is heated sufficiently to prevent gas adsorption or absorption thereon before the cryopump is operatively connected to a space to be evacuated therewith as a starting method for improving the cryopumping of, particularly, helium and a regenerating method after use of the cryopump.

Abstract: A cryopump having a generally axially symmetrical housing provided at one end with an entrance opening defined by a plane for passage of molecules of the gas to be pumped and plates defining condensation surfaces arranged to be brought to low temperature for condensation of molecules of the gas to be pumped, and a thermal radiation shield disposed in the region of the entrance opening, with the condensation surfaces being oriented substantially at right angles to the plane of the entrance opening and the radiation shield being composed of a plurality of elongate metal strips so positioned that their longitudinal axes are parallel to the condensation surfaces.

Abstract: A turbomolecular vacuum pump has a housing, a vertically oriented hollow pump rotor situated in the housing, and a vertically upwardly oriented stub shaft affixed to the housing and extending into the hollow pump rotor. The pump rotor is supported on the stub shaft by a magnetic axial bearing and at least one magnetic radial bearing, all disposed in the space surrounded by the hollow pump rotor.

Abstract: A turbomolecular vacuum pump has a stator, a rotor having a vertical axis of rotation and disposed in the stator; a drive motor for rotating the rotor; a downwardly open, axially extending chamber in the rotor; a vertically upwardly oriented, stationarily supported stub shaft projecting into the rotor chamber; and axial, as well as radial gas bearings disposed within the rotor chamber for generating gas cushions between the rotor and the stub shaft.