Abstract: The present invention is directed to a magnet for a magnetic bearing arrangement, a bearing arrangement comprising said magnet, and a vacuum pump comprising said bearing arrangement. In particular the invention can be particularly useful in a magnetic bearing arrangement that reduces stray magnetic fields for a turbomolecular vacuum pump, although it is understood that the invention is not limited to this field and other applications will be understood by the skilled person.

Abstract: A pump insert (50) for supporting a rotor (14) of a pump comprises an annular resilient support (52) for engaging the body (26) of the pump, the support (52) extending about a rolling bearing (10) having an inner race (12) for engaging the rotor (14), an axially preloaded outer race (16) fixed to the support (52), and a plurality of rolling elements (18) located between the races. During assembly, the rolling bearing (10) can be accurately positioned within the support (52) so that there is a very low tolerance stack-up when the insert (50) is fitted to the rotor (14). Consequently, the position of the rotor (14) will hardly change, if at all, when the rolling bearing (10) is replaced during servicing of the pump.

Abstract: The present invention is directed to a magnet for a magnetic bearing arrangement, a bearing arrangement comprising said magnet, and a vacuum pump comprising said bearing arrangement. In particular the invention can be particularly useful in a magnetic bearing arrangement that reduces stray magnetic fields for a turbomolecular vacuum pump, although it is understood that the invention is not limited to this field and other applications will be understood by the skilled person.

Abstract: Stray magnetic fields created by non-symmetrical magnetisation of the permanent magnets in a rotating magnet array of a magnetic bearing assembly, when used in turbo molecular pumps, can cause significant problems to devices such as scanning electron microscopes. In order to minimise the stray fields, at least the dipole and quadrupole moments of each magnet in the array is first measured. The magnets in the array are then arranged relative to one another such that both the dipole and quadrupole moments are minimised, thus minimising the stray magnetic field when the magnet array rotates in the turbomolecular pump.

Abstract: A pump insert (50) for supporting a rotor (14) of a pump comprises an annular resilient support (52) for engaging the body (26) of the pump, the support (52) extending about a rolling bearing (10) having an inner race (12) for engaging the rotor (14), an axially preloaded outer race (16) fixed to the support (52), and a plurality of rolling elements (18) located between the races. During assembly, the rolling bearing (10) can be accurately positioned within the support (52) so that there is a very low tolerance stack-up when the insert (50) is fitted to the rotor (14). Consequently, the position of the rotor (14) will hardly change, if at all, when the rolling bearing (10) is replaced during servicing of the pump.

Abstract: A pump insert (50) for supporting a rotor (14) of a pump comprises an annular resilient support (52) for engaging the body (26) of the pump, the support (52) extending about a rolling bearing (10) having an inner race (12) for engaging the rotor (14), an axially preloaded outer race (16) fixed to the support (52), and a plurality of rolling elements (18) located between the races. During assembly, the rolling bearing (10) can be accurately positioned within the support (52) so that there is a very low tolerance stack-up when the insert (50) is fitted to the rotor (14). Consequently, the position of the rotor (14) will hardly change, if at all, when the rolling bearing (10) is replaced during servicing of the pump.

Abstract: A vacuum pump comprises a housing, a drive shaft supported by a beating arrangement for rotation relative to the housing about an axis, and a pumping mechanism comprising a stator component mounted on the housing and a disk-shaped rotor component mounted on the drive shaft axially proximate the stator component. The bearing arrangement comprises a bearing supported in both radial and axial directions by a resilient support, comprising inner and outer annular portions connected by a plurality of flexible members, so that there is a fixed relation between the inner race of the bearing and the outer portion of the resilient support to determine the axial clearance between the rotor and stator components of the pumping mechanism.

Abstract: Stray magnetic fields created by non-symmetrical magnetisation of the permanent magnets in a rotating magnet array of a magnetic bearing assembly, when used in turbo molecular pumps, can cause significant problems to devices such as scanning electron microscopes. In order to minimise the stray fields, at least the dipole and quadrupole moments of each magnet in the array is first measured. The magnets in the array are then arranged relative to one another such that both the dipole and quadrupole moments are minimised, thus minimising the stray magnetic field when the magnet array rotates in the turbomolecular pump.

Abstract: A vacuum pump having a vacuum pumping mechanism mounted for rotation by a shaft and a brushless motor for rotating the shaft where the vacuum pumping mechanism comprises a turbo pumping mechanism comprising pumping stages, and a molecular drag pumping mechanism comprising at least one pumping stage, and a shaft supported for rotation by bearings, and where the motor comprises a permanent magnet rotor fixed relative to the shaft and the rotor has four poles and a stator has non-overlapping stator coils.

Abstract: A vibration isolator is described for inhibiting transfer of vibration to an apparatus during evacuation thereof by a pump. The isolator comprising a bellows for isolating from the ambient atmosphere fluid drawn from the apparatus by the pump. A first flange is connected to one end of the bellows for mounting the isolators the apparatus, and a second flange is connected to the other end of the bellows for mounting the isolator to the pump. The bellows surrounds a resilient element, preferably a helical tension spring, which is substantially co-axial with the bellows. The resilient element has a first end located proximate to the first flange and connected to the second flange, and a second end located proximate to the second flange and connected to the first flange.

Abstract: A turbomolecular vacuum pump (54) comprises a housing (70) and a rotor (52) supported by a bearing arrangement (64) for rotation relative to the housing (70). The bearing arrangement (64) comprises a bearing (72, 74, 76, 78) supported in both radial and axial directions by a resilient support (80) comprising inner (86) and outer (88) annular portions connected by a plurality of flexible members (84), the resilient support (80) having a radial stiffness in the range from 50 to 500 N/mm.

Abstract: A pre-compressed vibration damper is provided for inhibiting transfer of vibration to an apparatus during the evacuation thereof by a pump.

Abstract: A vacuum pump (50) includes a pumping arrangement, a shaft (10) for driving the pumping arrangement, a motor (60) for rotating the shaft (10) and a bearing arrangement supporting the shaft (10) for rotation, the bearing arrangement having a rolling bearing (12), supporting a first portion of the shaft (10), and a thrust bearing (30). The thrust bearing (30) houses a plurality of rolling elements (36) such that they are maintained in bearing contact with an outer race (18) of the rolling bearing (12) and a race (34) of the thrust bearing (30). In this way axial movement of the rolling bearing (12) can be resisted whilst allowing radial movement of the rolling bearing (12).

Abstract: A turbomolecular vacuum pump (54) comprises a housing (70) and a rotor (52) supported by a bearing arrangement (64) for rotation relative to the housing (70). The bearing arrangement (64) comprises a bearing (72, 74, 76, 78) supported in both radial and axial directions by a resilient support (80) comprising inner (86) and outer (88) annular portions connected by a plurality of flexible members (84), the resilient support (80) having a radial stiffness in the range from 50 to 500 N/mm.

Abstract: A lithographic apparatus is configured to project a pattern from a patterning device onto a substrate. The apparatus includes a gas purged sealing aperture extending between at least two different zones of the apparatus, and a gas supplier configured to supply the sealing aperture one or more gases selected from a group including hydrogen, deuterium, heavy hydrogen, deuterated hydrogen, and a mixture of argon and hydrogen.

Abstract: A vacuum pump comprises a housing, a drive shaft supported by a beating arrangement for rotation relative to the housing about an axis, and a pumping mechanism comprising a stator component mounted on the housing and a disk-shaped rotor component mounted on the drive shaft axially proximate the stator component. The bearing arrangement comprises a bearing supported in both radial and axial directions by a resilient support, comprising inner and outer annular portions connected by a plurality of flexible members, so that there is a fixed relation between the inner race of the bearing and the outer portion of the resilient support to determine the axial clearance between the rotor and stator components of the pumping mechanism.

Abstract: A vibration isolator is described for inhibiting transfer of vibration to an apparatus during evacuation thereof by a pump. The isolator comprising a bellows for isolating from the ambient atmosphere fluid drawn from the apparatus by the pump. A first flange is connected to one end of the bellows for mounting the isolators the apparatus, and a second flange is connected to the other end of the bellows for mounting the isolator to the pump. The bellows surrounds a resilient element, preferably a helical tension spring, which is substantially co-axial with the bellows. The resilient element has a first end located proximate to the first flange and connected to the second flange, and a second end located proximate to the second flange and connected to the first flange.

Abstract: A vacuum pump having a vacuum pumping mechanism mounted for rotation by a shaft and a brushless motor for rotating the shaft where the vacuum pumping mechanism comprises a turbo pumping mechanism comprising pumping stages, and a molecular drag pumping mechanism comprising at least one pumping stage, and a shaft supported for rotation by bearings, and where the motor comprises a permanent magnet rotor fixed relative to the shaft and the rotor has four poles and a stator has non-overlapping stator coils.

Abstract: A lithographic apparatus includes a patterning device for patterning a beam of radiation, a projection system for projecting the patterned beam of radiation onto a substrate, a gas purged sealing aperture extending between different zones of the apparatus, and a gas supply arrangement for supplying a mixture of at least argon and hydrogen to the sealing aperture.

Abstract: A pre-compressed vibration damper is provided for inhibiting transfer of vibration to an apparatus during the evacuation thereof by a pump.