Abstract: A radial position sensor includes four capacitive electrodes oriented about a shaft, arranged in two diametrically opposite pairs. Sensor circuitry generates an output signal in proportion to the capacitance between the electrodes and the shaft; the capacitance between an electrode and the shaft increases as the shaft approaches the electrode and decreases as the shaft recedes from the electrode. The sensor circuitry applies an alternating voltage to one electrode of a pair and a 180 degree out of phase alternating voltage to the other electrode of the pair. The electrical responses of the two electrodes to their respective input signals are summed to form a radial deviation signal which is relatively free from the alternating voltage and accurately represents the position of the shaft relative to the electrodes of the pair.

Abstract: The present invention is directed to a seal for demountable joints operating over a wide temperature range down to liquid helium temperatures. The seal has anti-extrusion guards which prevent extrusion of the soft ductile sealant material, which may be indium or an alloy thereof.

Abstract: A gas thrust bearing for a shaft mounted for rotation and limited axial movement in a housing. As disclosed, the axial shaft load is supported by pressurized gas between an end of the shaft serving as a first thrust surface and a cylindrical thrust pad providing a second thrust surface having an outlet orifice at its center. Pressurized gas is introduced between the shaft and the housing and flows between the thrust surfaces to the outlet orifice. The outlet orifice is surrounded by a small raised annulus. The thrust pad carrying the second thrust surface is supported on a flexible diaphragm which moves in response to changes in the thrust load in a manner to damp out oscillations of the shaft.

Abstract: In a regenerative rotodynamic compressor, a portion of a disc-like impeller adjacent the impeller periphery extends radially through an annular chamber in the compressor casing concentric with the impeller, thereby dividing said chamber into two annular side channels, one on each side of the impeller. The portion of the impeller lying in the annular chamber has scooped out annular cavities or recesses in its sides in which are disposed rings of aerodynamic blades, and fluid flow passing around the annular chamber from an inlet to an outlet is caused to circulate repeatedly, flowing radially outward through the blading in the impeller cavities and radially inward in the annular side channels alongside the impeller outside the impeller cavities. The aerodynamic blades are designed so that the angle between the entry and exit flows of each blade is greater than 90.degree..

Abstract: A regenerative fluid dynamic machine, typically a blower or exhauster, includes a rotor (21) having a set of blades (24) which are curved, and preferably of aerofoil cross-section, in a manner which causes fluid flow passing through the set of blades to be turned with respect to the blades through an angle more than 90.degree., preferably 100.degree. to 140.degree.. The rotor is enclosed in stator structure (20) defining a toroidal passage (25) between inlet and outlet ports (26, 27) fluid flow in said passage following a path which forms a spiral centered within the cross section of the passages so that it passes through the set of blades more than once between the inlet and outlet.

Abstract: In a regenerative rotodynamic compressor, a portion of a disc-like impeller adjacent the impeller periphery extends radially through an annular chamber in the compressor casing concentric with the impeller, thereby dividing said chamber into two annular side channels, one on each side of the impeller. The portion of the impeller lying in the annular chamber has scooped out annular cavities or recesses in its sides in which are disposed rings of aerodynamic blades, and fluid flow passing around the annular chamber from an inlet to an outlet is caused to circulate repeatedly, flowing radially outward through the blading in the impeller cavities and radially inward in the annular side channels alongside the impeller outside the impeller cavities. Shroud rings at the blade tips form cores around which this circulation takes place. The blades are cast integrally with the impeller disc or with the shroud rings.