Abstract: A rotor drive shaft assembly for use in a centrifugation system. The rotor drive shaft has a bearing material configured as a sleeve and mounted on the inside wall of a spindle hub with a clearance existing between the sleeve and a housing that surrounds the lower base of the shaft. When the rotor and hub experience radial displacement at a critical speed, the sleeve makes contact with the housing in order to limit further radial displacement. Alternatively, the sleeve can be mounted on the outside of the housing with the clearance existing between the sleeve and the spindle hub, with the sleeve making contact with the spindle hub at the critical speed in order to limit further radial displacement. In another embodiment, a support tube is provided which surrounds the lower portion of the shaft with a clearance existing between the shaft and the support tube.

Abstract: An improved configuration of refrigerant tubing and means for attaching the tubing to the centrifuge chamber. The tubing is preformed to provide a flat contact surface against the outside surface of the centrifuge chamber. The centrifuge tubing is tightly wound around the centrifuge chamber in a continuous fashion including a flat spiral at the base of the centrifuge chamber. For the section of the tubing in contact with the vertical cylindrical wall of the centrifuge chamber, the pressure for maintaining contact pressure between the flat surface of the tubing and the chamber wall is provided by the tension in the wrapping of the tubing. For the section of the tubing at the base of the centrifuge chamber, contact pressure may be provided by a clamping mechanism. To further enhance heat transfer between the refrigerant coils and the centrifuge chamber, a high heat conductive epoxy may be applied between the tubing and the centrifuge chamber surface.

Abstract: A centrifuge includes a drive shaft-to-hub coupling assembly for providing vibration damping that is selective to torsional damping over lateral damping. An impeller is fixed to a drive shaft and a receiver is fixed to a rotor-bearing hub. Relative rotation between the impeller and the receiver is restricted to compression and decompression of elastomers trapped between teeth extending from the impeller and from the receiver. The elastomers function to damp torsional vibrations and torsionally induced lateral vibrations. The receiver is prevented from becoming axially misaligned with the impeller by including one or more rigid annular bushings that maintain the distance between the hub and the drive shaft, thereby preventing the elastomers from being deformed in a manner which would damp lateral vibrations. The annular bushing is mounted to allow relative rotation between the impeller and the receiver.

Abstract: An assembly for transferring rotation from a centrifuge drive system to a centrifuge rotor includes a hub that is connected to the drive system for rotation about an axis. A sleeve member is attached to the hub in a position to support the centrifuge rotor. The sleeve member is formed of a material having a low coefficient of friction and is positioned to reduce the likelihood of rotor-to-hub lock. The resistance of the sleeve member to wear and to the absorption of foreign matter are also important in the selection of a material for forming the sleeve member. An acetal-based compound is preferred. By connecting the sleeve member to the hub such that the exterior surface of the sleeve member is raised relative to the surface of the hub, rotor-to-hub contact is reduced, thereby further reducing the risk that the rotor and the hub will become locked to one another.

Abstract: A device for centrifugally separating a sample includes a housing which defines an enclosed chamber from which gas is evacuated via an evacuation port protected by a spinning rotor. The evacuation port is preferably located proximate to the axis of rotation of the rotor and within the interior of the rotor. A drive shaft connects the rotor to a motor positioned outside of the chamber. An annular sleeve having an inside diameter greater than the diameter of the shaft extends coaxially along the drive shaft into the chamber. The outlet of the gap between the drive shaft and the annular sleeve defines the evacuation port. A hub is fixed to the upper end of the drive shaft and includes a downwardly depending skirt that has an inside diameter greater than the outside diameter of the annular sleeve. Gas evacuation from the chamber is initially in an upward direction along the gap between the hub skirt and the sleeve and in a downward direction from the evacuation port to a vacuum pump.

Abstract: A salt belt for insertion into a centrifugal test rotor is provided which is used to hold and contain a plurality of test components during mechanical testing. The slat belt is a flat polymeric belt which adhesively affixes a plurality of L-shaped slat members to its upper surface. When the belt is laid flat, it accommodates the easy positioning of components into channels. As the belt is curled for insertion into the test rotor, the slats move closer to one another and clasp the components into channels formed by adjacent pairs of radially directed slat arms. Upon completion of the test run, the slat belt is removed from the rotor and unrolled whereby the components are easily removed from the belt.

Abstract: A liquid flow monitor. The device includes a thermistor placed in the path of liquid flow. A circuit including the thermistor in a Wheatstone bridge is used to sense the liquid flow by sensing the change in resistance of the thermistor. A transistor connected to the bridge is used to maintain the thermistor within predetermined levels to prevent overheating of the device.

Abstract: A tube-cutting apparatus and method for separating centrifuged materials are shown in which a resilient axial compressive force is exerted on the tube during cutting by spaced tube-holding members; and the cutting knife has flat upper and lower sides against which the severed portions of the tube are held in sealing engagement by the axial force. Independent adjustment is provided for (a) the relative positions of the tube and the cutting knife, and (b) the relative positions of the spaced tube-holding members.

Abstract: A thick walled centrifuge tube with a generally constant internal diameter and having at least one circumferential groove within the exterior surface of the tube. The groove is designed to have a depth slightly less than the wall thickness of the tube. The circumferential groove is designed to assist in slicing of the tube subsequent to centrifugation in order to isolate different separated particles of a fluid sample which have formed fraction bands at certain levels in the tube. The groove reduces the cutting force required to partition the tube. The groove provides a guide for a slicing blade. The groove is formed in such a manner that a fluid tight seal is formed between the slicing blade and the tube as the blade proceeds through the tube. The centrifuge tube wall at the base of the groove, after slicing, is resilient enough to allow the tube sections to be rejoined under force and create a fluid tight seal.

Abstract: A variable slip drive system for driving a variable speed induction motor. The system includes a tachometer for providing a signal proportional to the speed of the motor and a slip oscillator. The output of the tachometer and slip oscillator are combined by a motor drive oscillator to provide a motor drive signal. The frequency of the motor drive signal equals the tachometer signal, less the frequency of the slip signal. The motor drive signal is converted into a proportional, three-phase, high power signal for powering the motor. The frequency of the slip signal is controlled so as to be proportional to the motor speed as a means of optimizing the motor's performance.

Abstract: A centrifuge rotor for carrying a plurality of centrifuge tubes at a fixed angle with respect to the spin axis of the rotor wherein the rotor has a containment annulus located above the tube cavities in the rotor for containment of any excess fluid from the centrifuge tubes during centrifugation. The containment annulus is designed in such a manner that it will receive all possible excess fluids from the centrifuge tubes during centrifugation and none of the excess fluid will contact or exert pressure on the rotor lid.

Abstract: A rotor having a plurality of swinging carriers designed to receive specimen samples for subjection to centrifugation. The carriers are pivotally mounted to a rotor frame in such a manner that the generally flat support faces of each of the carriers assumes a parallel orientation with respect to the rotational axis of the rotor during operational speeds of the rotor. When the rotor is not operating, the support surfaces of each of the carriers assumes the perpendicular or acute angle orientation with respect to the rotational axis of the rotor. In order to overcome any resistive frictional forces which may be generated at the interface between the rotor frame and the pivoting carrier, the pivot axis of the carrier is shifted from the central or center of gravity plane of the carrier to ensure that the support surface of the carrier will positively assume its proper parallel orientation with the rotor spin axis.

Abstract: A vacuum seal for use in a continuous flow centrifuge apparatus for minimizing heat transfer from the vacuum bushing to the rotary transfer tube which is conducting the sample solution to the centrifuge rotor. An elongate, cylindrical sleeve surrounds the transfer tube, coaxial therewith and spaced therefrom, adjacent the upper end thereof, between the transfer tube and the vacuum bushing, the bushing creating an oil film around the transfer tube to provide the vacuum seal, the annulus formed between the inner surface of the sleeve and the outer surface of the transfer tube isolating the transfer tube from the heat created in the oil film.

Abstract: In a swinging bucket centrifuge rotor of the type including a core with outwardly extending support arms having removable trunnion pins for supporting a plurality of bucket assemblies, each bucket assembly including a rotor bucket support having a pocket on opposite sides thereof for receiving the extremities of adjacent pins, there is disclosed an improvement wherein each of the arms has only a single hole formed in the outer end thereof, perpendicular to the longitudinal axis thereof, for receipt of a single trunnion pin including a central portion and acutely oriented opposite extremities, the opposite extremities of each trunnion pin extending outwardly from the arms towards and coaxial with the outwardly extending extremities of the pins of adjacent arms, and wherein the pockets in each support are cut into the sides thereof at an acute angle relative to the axis thereof.

Abstract: In a centrifuge including a centrifuge rotor and a drive shaft for spinning the rotor at selected rotational speeds, a safety device adapted to prevent the rotor from attaining a rotational speed likely to cause the rotor to explode with a force that could not be contained within the centrifuge housing. The device includes a safety link handle assembly supported on the top of the rotor on the rotation axis thereof having an arm designed to rupture and depart from the handle assembly at a predetermined speed thereby creating an imbalance condition of such a magnitude that the rotor separates from the drive shaft and is thereby prevented from attaining a hazardous rotational speed.

Abstract: A centrifuge test tube cap assembly for a thin flexible test tube including a stem member having a stud adapted to extend out the mouth of the test tube and having a cylindrically shaped skirt dimensioned to fit snugly within the inner surface of the mouth of the test tube, the stem member also having a slanting annular surface between the skirt and the stud, slanting outwardly in the downward direction, and the assembly also including a crown member having a depending outer lip, the outer diameter of which is substantially the same as the outer diameter of the thin flexible tube and having an annular inner surface slanting outwardly in the downward direction, the slanting surface of the lip conforming to the shape and slant of the slanting annular surface of the stem member so that when the crown is positioned over the stem and tightened axially on the stem member the upper edge of the flexible tube is deformed inwardly to squeeze the upper edge of the tube between the respective slanting surfaces of the ste