A magnet apparatus for generating a high gradient and/or high strength magnetic field, comprises: two main permanent magnets 2, 4 located side-by-side with oppositely oriented magnetic field polarities and end surfaces of opposite polarities next to one another, wherein the magnetic anisotropy of the magnets 2, 4 exceeds the magnetic induction of the material of the magnets 2, 4; and at least one mask 6 on a first end of each of the adjacent permanent magnets 2, 4, the masks 6 comprising a permanent magnet material covering adjacent end surfaces of the two permanent magnets 2, 4 with a gap 8 in the masks along a joining line between the two permanent magnets 2, 4 to form a zone of high-gradient magnetic field above the joining line; wherein the permanent magnet of each mask 6 is oriented with an opposite polarity to the main permanent magnet 2, 4 that it is attached to.

The magnetic bearings make use of magnet assemblies with a high magnetic field gradient. The magnet assemblies use two permanent magnets with opposite polarization in a Kittel open domain structure. The basic factor of magnetic separation is the magnetic force, which acts on a particle of the substance and which is proportional to the magnetic susceptibility of the substance, the value of the magnetic induction B and the value of the gradient B of the applied magnetic field. Therefore, increasing the sensitivity and selectivity of magnetic separation will require use of the highest possible values of magnetic induction B and magnetic field gradient B, or their united factorthe product BB. The magnetic assembly have repulsive magnetic systems each having two juxtaposed permanent magnets 2, 4 with opposite magnetization in the form of a Kittel open domain structure. In such an system, near the edges of the faces of the joining magnets, a strong magnetic stray field appears and the value of the product BB reaches 10.sup.11 mT.sup.2/m. To concentrate the magnetic stray field shields 6 are provided on top of the two magnets 2,4 with a gap 8 between the shields at the joint of the two magnets 2, 4 forming zones of high magnetic field gradient 14 with increased magnitude for the product BB.

A landing bearing assembly for a rotary machine rotatable around a central axis and having a stator, a rotor with a shaft, a magnetic bearing, an auxiliary rolling bearing with two lateral faces, a landing sleeve facing, in normal operation of the rotary machine when the rotor is supported only by the magnetic bearing, the auxiliary rolling bearing at a nominal distance defined as the landing airgap El, the auxiliary rolling bearing coming into contact with the landing sleeve upon landing of the rotor in the event of a high shock. The assembly further provides a compliance ring with a nominal thickness Eo made from a material with a lower mechanical stiffness than the material constituting the other components of the landing bearing assembly to first absorb some energy of the shock by elastic deformation resulting in a reduction of its thickness.

A roller module includes a roller, a magnetic bearing, a permanent magnet, at least one pair of magnetic coring, and a plurality of gap sensors. The roller has a protrusion and has a cylindrical shape. The protrusion is formed at both outer surfaces of the roller with a stepped portion and has the cylindrical shape. The magnetic bearing is formed at the roller. The permanent magnet is formed at the roller. At least one pair of magnetic coring covers an outer circumference of the protrusion. The gap sensors are formed along an axial direction and a radial direction of the roller.

A hybrid magnetic suspension of a rotor (1) having compressor wheels (2, 3) having permanent magnets (104, 114) integral to shrunk fit rings (8, 18) arranged on the rotor (1) in the vicinity of the compressor wheels (2, 3), permanent magnets (124, 134) integral to stationary rings (23, 33) coaxially arranged with the rotor (1) and associated with a resilient material (5, 15) to define a passive radial magnetic bearing, coils (6, 16) associated with magnetic armatures (10, 20) and facing rotor parts (7, 17) being located perpendicularly to the rotor (1), and axial sensors (60, 160) configured for sensing the axial position of the rotor (1) and control means (200) configured for feeding the coils (6, 16) as a function of the outputs of the axial sensors (60, 160) for generating both axial bearing forces and a motor torque and thereby being adapted for defining an axial bearingless motor.

A hybrid airfoil bearing for a shaft is provided and includes airfoil bearing components and passive magnetic bearing components. The airfoil bearing components include a top foil immediately surrounding the shaft and additional components. The passive magnetic bearing components are integrated into the shaft and the additional components of the airfoil bearing components to remove a static load of the shaft on the top foil.

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.

The present invention relates to a rim driven propeller unit for a vessel, where a number of permanent magnets (4) are arranged round the propeller unit's rotatable rotor housing (1), comprising a number of propeller blades (3), and a number of permanent magnets round the propeller unit's external, stationary casing (2) housing the rotatable rotor housing, where the permanent magnets round parts of the rotatable rotor housing and the external, stationary casing's circumference are provided located above one another with like polarity, while other parts of the rotatable rotor housing and the external, stationary casing are provided located facing one another with opposite polarity, whereby the rotor housing and the stationary casing are repelled by and attracted to one another respectively, thereby being prevented from coming into contact with one another.

A hybrid airfoil thrust bearing is provided for a shaft including a thrust disc that rotates with the shaft. The hybrid airfoil thrust bearing includes airfoil bearing components and passive magnetic bearing components. The hybrid airfoil bearing components include a first top foil immediately adjacent to a first side of the thrust disc and surrounding the shaft, first additional components, a second top foil immediately adjacent to a second side of the thrust disc and surrounding the shaft and second additional components. The passive magnetic bearing components are integrated into the thrust disc and into the first and second additional components to remove a static load of the thrust disc on the first top foil and on the second top foil.

A compressor assembly is provided and includes a fluid pathway, a compressor disposed and configured to compress fluid flowing along the fluid pathway and a motor configured to drive operations of the compressor. The motor includes one or more hybrid airfoil bearings to support the shaft within a housing. Each of the one or more hybrid airfoil bearings includes airfoil bearing components including a top foil immediately surrounding the shaft and additional components and passive magnetic bearing components integrated into the shaft and the additional components of the airfoil bearing components to remove a static load of the shaft on the top foil.