Abstract: An electromagnetic, reciprocating linear motor or alternator having at least two armatures that are adjacent along an axis of reciprocation. The armatures have gaps that are linearly aligned along a gap path parallel to the axis. Field magnets reciprocate within the gap path. The field magnets include a main field magnet associated with each armature, each main field magnet having a magnetic polarization in the same direction across the gap path. A secondary magnet provides a centering spring force and is interposed between the main magnets. The secondary magnet extends in an axial direction from within a gap of one armature core to within an adjacent gap of an adjacent armature core. The secondary magnet is magnetically polarized in a direction opposite the polarization of the main magnets.

Abstract: An electromagnetic, reciprocating linear motor or alternator having at least two armatures that are adjacent along an axis of reciprocation. The armatures have gaps that are linearly aligned along a gap path parallel to the axis. Field magnets reciprocate within the gap path. The field magnets include a main field magnet associated with each armature, each main field magnet having a magnetic polarization in the same direction across the gap path. A secondary magnet provides a centering spring force and is interposed between the main magnets. The secondary magnet extends in an axial direction from within a gap of one armature core to within an adjacent gap of an adjacent armature core. The secondary magnet is magnetically polarized in a direction opposite the polarization of the main magnets.

Abstract: An apparatus and method for compressing gas refrigerant using two different compressors operated alternatively in a series or parallel mode for obtaining two different compression ratios and thereby provide efficient operation for both a relatively lower suction pressure and a relatively higher suction pressure. This system avoids an unbalanced mass flow rate when the compressors are operated in series by unloading a downstream one of the compressors. When operated in the series mode, refrigerant is bypassed back to a suction inlet of the downstream compressor during a portion of a compression stroke of the downstream compressor for equalizing the mass flow rate through the two compressors.

Abstract: Apparatus and method for separating oxygen directly from air, operating at substantially atmospheric pressure and recuperating energy used for cooling incoming air. An ambient air input leads from the atmosphere to a vessel for confining gases. A cryocooler has a cooled surface in the vessel for directly condensing oxygen from the air at substantially atmospheric pressure. The cryocooler cools the cold surface to a temperature greater than the boiling point temperature of nitrogen and not greater than the boiling point temperature of oxygen for condensing oxygen. A liquid/gas separator separates the liquid oxygen from residual gases which both flow out through separate outputs. Air is propelled through the system at substantially atmospheric pressure by an air impeller. A heat exchanger recovers cooling energy and dehumidifies incoming air by transferring heat from the incoming air to outgoing gases.

Abstract: The free piston cooler transient temperature control system of the present invention eliminates collisions during the transient cool-down period in a free piston cooler upon start-up. The transient temperature control system incorporates a free piston cooler, having a cold head and a warm end, a cold head temperature sensor, a relational interface, and a temperature controller. The cold head temperature sensor senses the temperature of the cold head and generates a temperature signal. The relational interface is in communication with the temperature signal and contains a predetermined relationship between the cold head temperature and a maximum piston stroke during the transient cool-down temperature range. The relational interface generates a transient range maximum allowable stroke signal from the temperature signal and the predetermined relationship.

Abstract: A method of forming a heat exchanger apparatus on a housing wall. The heat exchanger includes inner and outer annular rings. The rings have heat radiating, high surface area fins attached on oppositely facing surfaces. The inner ring has a radially outwardly facing surface that abuts the interior surface of the housing sidewall. The outer ring has a radially inwardly facing surface that abuts the exterior surface of the housing sidewall. When displaced longitudinally along the ring axes, which are coincidental, the sidewall is clampingly engaged therebetween, and an excellent thermal flow path is formed. Heat transferred into the inner fins from a working gas is conducted to the inner ring, through the sidewall, into the outer ring, then into the outer fins. Air impinging upon the outer fins absorbs the heat from the outer fins.

Abstract: A gas bearing structure including a cylindrical core and a cylindrical sleeve. The core has a radially outwardly facing surface with longitudinal and circumferential grooves formed thereon. The sleeve has a radially inwardly facing surface that sealingly abuts the outer core surface. The inwardly facing sleeve surface bridges over the grooves, defining fluid, preferably gas, flow paths within each groove. The gas flow paths permit gas to flow from the workspace to radial passages formed through the sleeve sidewall, thereby forming a gas bearing.

Abstract: In a free piston machine, a coil is mounted to its housing and magnetically linked to a permanent magnet or electromagnet on its piston member to form a linear motor. The coil and magnet are either added to embody the invention or are part of an AC linear alternator or AC linear motor which are a part of the free piston machine. A source of DC electrical current and a switch for connecting the DC source to the coil supply DC current to the coil when the switch is closed so that the coil and magnet temporarily operate as a DC linear motor until the piston is adequately centered for start-up without collision. The DC source voltage is temporarily applied to the coil to move the piston away from an end wall of the cylinder. This is accomplished by applying the DC current to the coil for a predetermined time interval, or by sensing when the piston has reached an adequately centered position.