A passive superconductor bearing system and process for supporting a rotating member uses permanent magnets in the bore of the rotating member, stationary permanent magnets which encircle the shaft, superconducting materials at the shaft ends, and a duct and pinhole outlet which directs a flow of gas towards one shaft end. The stationary permanent magnets interact with the permanent magnets in the shaft to radially position the shaft in the center of the stationary permanent magnets due to radial repulsive forces between poles of the same polarity. In order to enhance stability, a gas jet is directed towards one end of the shaft to counteract the unbalancing axial force on the shaft caused by permanent magnet interaction. The superconductor-magnet interaction generates a restoring force as the shaft is transversely displaced in any direction away from its equilibrium position. The interaction does not assist shaft rotation, but adds to the stiffness and damping of the bearing system.
Highly-miniaturized rotary artificial hearts small enough to be implanted within the natural heart are provided. The entire radial load of a high-speed pump rotor and most of the axial load is carried by a radially stable arrangement of high-energy-product permanent magnets. The rotor is fully suspended and rotated magnetically, with the exception of a single thrust-bearing contact point which utilizes ultra-hard, wear-resistant material, preferentially diamond, located at the axis of rotation in a high-flow region of the pump. No sensors or electromagnets are required for the bearings. One preferred embodiment utilizes dual mirror-image axial or mixed flow impellers mounted on a single axis so as to pump from a central inflow port out both ends of the device. This achieves thrust balancing, reduces pump speed by approximately half for a given flow and pressure, and is well-accommodated anatomically with double outflow grafts, one anastomosed directly to the aorta within the heart, and the second connected via the apex to the descending thoracic aorta.
A damping arrangement (FIG. 1) for axial vibrations in a turbomachine shaft 10 comprises at least one circumferentially extending annular damping chambers 34 and 35 open towards a shaft thrust face 19.sub.A and 19.sub.B of a radially extending collar 20 and to which gas is supplied alternately by gas flow controllers 42.sub.A and 42.sub.B. Each controller contains fluidic devices switched by sensing pressures in radially displaced pressure sensing chambers 51, 53, or even the same chambers, as such pressure are modulated by the variations in shaft and collar position, to divert the gas from source 40. The diversion of gas flow is arranged to cause pressure fluctuations, which exert axial thrust on the thrust faces, advanced in phase to approach of the shaft so as to damp the vibration. The fluidic devices may be implemented by flow amplifiers 47.sub.A, 47.sub.B or fluid logic flip flop 61 (FIG. 2) and may be multistage devices to increase gain, all of which may be formed without moving parts and embedded in the housing. Flow diversion may be effected by other forms of sensing, such as leakage from a nozzle facing the shaft. The arrangement may be combined with, or serve as, a gas seal or be part of a bearing arrangement.
A ferromagnetic member (21) of a movable part (2) is disposed on a side of a stationary part (1) such that the ferromagnetic member (21) faces a high temperature superconductor (11) of the stationary part (1). The high temperature superconductor (11) is brought into a superconductive state by cooling it to a temperature below a critical temperature in a magnetic field. The magnetic flux pinned to the high temperature superconductor (11) is caused to pass through the ferromagnetic member (21) so that an attractive force is generated between the high temperature superconductor (11) and the ferromagnetic member (21) to hold the movable part (2). When the ferromagnetic member (21) has a shape such that when the gap becomes lower than a predetermined value, the attractive force decreases, the movable part (2) can be stably suspended in a non-contacting manner, without the necessity of control, by the combination of the high temperature superconductor (11) and the ferromagnetic member (21).
A superconducting bearing assembly includes a coil field source that may be superconducting and a superconducting structure. The coil field source assembly and superconducting structure are positioned so as to enable relative rotary movement therebetween. The structure and coil field source are brought to a supercooled temperature before a power supply induces a current in the coil field source. A Meissner-like effect is thereby obtained and little or no penetration of the field lines is seen in the superconducting structure. Also, the field that can be obtained from the superconducting coil is 2-8 times higher than that of permanent magnets. Since the magnetic pressure is proportioned to the square of the field, magnetic pressures from 4 to 64 times higher are achieved.
An apparatus, and methods of making and using the apparatus, including at least a first path of magnetic flux perpendicular to and penetrating a first plane in space; preferably, a second path of magnetic flux perpendicular to the first plane and having a gradient such that no net flux passes the first plane; and a passive first null flux coil adjacent to the first plane; whereby when one of the first null flux coil and a combination of the paths is moving, the first null flux coil and the paths, combinatorily, are magnetically induced into alignment with respect to the first plane.
