Abstract: A lubricating system which is completely self contained within the vacuum environment of an electric direct drive system for an ultracentrifuge rotor. The lubricating system also functions as a cooling means for an electric motor within the drive system by the use of a unique cooling feed tube in the central portion of the drive system. An orifice in the top of the cooling feed tube will control the head of the lubricating medium within the system. Specific design of the fit between the direct drive assembly and the drive housing in conjunction with the head on the lubricating medium will regulate the drip rate of the lubricating medium to the bearings. The use of the unique lubrication and cooling system maintains the close tolerances of the various elements such as the high speed bearings of the drive system because the temperature of the overall drive system is controlled.

Abstract: In accordance with the present invention, there is provided an air driven centrifuge including a rotor housing having an access door in which there is mounted the illuminating and sensing elements of a photo-optical tachometer with the elements so constructed and arranged that they are positioned over the rotor when the door is in a closed position. There is also provided a rotor cover having at least a portion of its surface conditioned to alternately absorb and reflect incident light, and digital display means to display the rotor speed in R.P.M.

Abstract: A gas discharge display having valve means comprising a pellet cooperating with a conical opening of a base plate of a display panel, the valve means allowing the continuous introduction of mercury vapor from a liquid mercury reservoir to the envelope of the display, but preventing the entrance of liquid mercury.

Abstract: A test tube holder for insertion into a cylindrical test tube cavity in a centrifuge rotor to support a plurality of relatively small test tubes within the rotor cavity. The holder includes a body whose shape is substantially that of a cylinder or a longitudinal section thereof. The body has a plurality of small cavities for holding test tubes, the smaller cavities being spaced apart in a direction along the longitudinal dimension of the body. Each of the smaller cavities is arranged at an angle relative to the longitudinal dimension of the body, and each has a mouth opening onto an exterior surface of the body. The test tube holder further includes means for orienting the holder in the centrifuge rotor test tube cavity so that the mouths of the smaller cavities face the rotational axis of the centrifuge rotor when the test tube holder is inserted into said centrifuge rotor test tube cavity.

Abstract: A large diameter air driven centrifuge rotor which holds a plurality of centrifuge tubes in a fixed horizontal position. The rotor is designed to operate in a stable and smooth condition on a rotor seat which is smaller than the diameter of the rotor. Although the rotor essentially covers the rotor seat portion of the centrifuge, the rotor is designed in such a manner that the air flow from the driving air being exerted on the rotor will properly exit from between the rotor and the seat without affecting a stable smooth operation of the rotor.

Abstract: A fluid-containing means for each bore of a centrifuge rotor is disclosed which combines a self-capped tube and a floating cap resting on the top of the tube and arranged to resist deformation of the tube by the centrifugal forces developed therein. The floating cap has an annular skirt which engages the top of the tube and which is sufficiently thick in cross-section to prevent deformation of the floating cap. The floating cap is formed from a relatively light plastic, having a density less than that of the centrifuged fluid, thereby preventing bottoming of the floating cap in the bore in the event of rupture of the tube.

Abstract: A substantially enclosed centrifuge tube having a small fill or access port at one end. In its preferred form there is integrally formed adjacent the fill port a neck or stem which is fused to hermetically seal the centrifuge tube to provide a permanent and complete seal of the centrifuge tube. A plug is securely mounted within the centrifuge rotor above the centrifuge tube when placed in the rotor to provide solid support adjacent the complete exterior surface of the tube. The interior of the plug is shaped to conform and mate with the upper end of the centrifuge tube. The use of a removable capping means placed on the centrifuge tube is eliminated. Access to the tube subsequent to the centrifugation run requires puncturing or cutting of the tube.

Abstract: A centrifuge tube holder designed for use in a centrifuge rotor to hold a plurality of small volume tubes in such a manner that, when the centrifuge rotor is at rest, the tubes will be oriented at an inclined angle, but will assume essentially a horizontal orientation when the centrifuge rotor is operating. The holder provides improved collar support for the centrifuge tube during centrifugation and also provides for the inclusion of a tube pivot point in the plate to enhance the proper movement of the tube from its at-rest position to the correct support position during operational speeds of the centrifuge rotor.

Abstract: A multiplexed display system which prevents closely positioned electrodes from causing erroneous displays. The electrodes are divided into selectively enabled groups. The electrodes are connected to switching circuits in a pattern such that the first one or more electrodes in each group are not connected to the same switching circuits as any of the electrodes in the preceding group, and the last one or more electrodes in each group are not connected to the same switching circuits as any of the electrodes in the next succeeding group.

Abstract: A centrifuge tube holder which not only provides support for the tubes in a vertical orientation when placed on a workbench, but also horizontal and radial support when the tubes are placed in a centrifuge rotor. The tube holder has at least two sections which are pivotally connected to allow for upright or vertical orientation of the tubes when placed on a workbench. The two sections can be pivotally oriented with respect to each other to place the tubes horizontally in a centrifuge rotor at different radial angles with respect to each other with reference to the spin axis of the rotor. The holder also incorporates means for securely holding the tubes within the holder while they are being transported, so that the holder can be inverted without the escape of the tubes. On the other hand, the biasing or securing means for the tubes in the holder is eliminated when the holder is at rest on the workbench to permit convenient and easy insertion or removal of the centrifuge tubes.

Abstract: A temperature regulating apparatus which increases optical sensitivity and resolution of a liquid in a reaction chamber by heating while providing rapid cooling to prevent vaporization of the liquid within the reaction chamber. The apparatus includes a heat exchanger containing the reaction chamber and an insulating chamber surrounding the heat exchanger. A coolant may be passed through the heat exchanger to prevent boiling should a change in liquid flow make such occurrence likely. The change in liquid flow is monitored by an analyzer monitor, and the temperature in the reaction chamber is changed accordingly.

Abstract: A modular spacer concept is disclosed for use in centrifuge bores. The arrangement is such that various sizes of tubes are available to allow for different amounts of fluid which may be inserted therein for centrifugation. A plurality of substantially identical spacers are provided, each of which has an effective length equal to a predetermined standard difference in tube sizes. The lower surface of each spacer has a concave center portion adapted to fit the convex center portion of the upper surface of a tube, and the upper surface of each spacer has a convex center portion adapted to fit the concave center portion of the lower surface of a substantially identical spacer.

Abstract: A method of closing or sealing a filler passage formed in a neck or stem protruding from the small access opening in the upper end of a substantially closed centrifuge tube. The neck is formed of a readily fusible material and a heat conductive cap member is positioned over the open end portion of the neck closely confining it therein. Heat and pressure are applied to the cap causing progressive portions of the neck to melt and fold into the filler passage where it forms a molten mass within the filler passage above the access opening to the tube. Heat and pressure are removed, permitting the cap to cool and the molten mass to solidify completely sealing or filler passage of the centrifuge tube. The cap is then removed and the centrifuge tube is fully prepared for centrifugation.

Abstract: A closed-loop drive system for variable speed induction motors for maintaining a constant slip frequency, regardless of motor speed. A slip frequency oscillator generates a signal having a frequency proportional to the desired slip of the motor and a tachometer generates a signal having a frequency proportional to the actual rotational speed of the motor. The stator frequency is the sum of the rotor speed and the slip frequency during acceleration and the difference between the rotor speed and the slip frequency during braking. Exclusive OR gates are used to add the slip frequency signal either to the tachometer signal or to the stator signal, the outputs of the gates being applied to a digital phase detector. The phase detector drives a voltage controlled oscillator which provides the stator signal. The output of the voltage controlled oscillator is used to trigger the slip frequency oscillator to prevent overlap of pulses to the digital phase detector.

Abstract: In an overspeed protection system for a centrifuge apparatus of the type including a rotor driven by a drive motor, a transducer for providing a signal whose frequency is a function of the rotational speed of the centrifuge rotor, an oscillator for generating a reference signal having a predetermined frequency, means for mixing the rotational speed signal with the reference signal to provide a difference frequency signal, a filter coupled to the output of the mixing means for passing signals having frequencies below a predetermined frequency, and means coupled to the filter for disconnecting power to the drive motor in response to an output signal from the filter, there is disclosed an improvement comprising a frequency comparator responsive to the rotational speed signal and the reference signal for generating an overspeed signal when the frequency of the rotational speed signal exceeds the frequency of the reference signal, and means for combining the outputs of the filter and the frequency comparator at th

Abstract: A multi-contact rotary switch in which arcuate cam lobes on the planar faces of a rotatable disc-shaped cam rotor selectively engage a plurality of switch elements. Each switch element is attached to one of two switch blocks positioned adjacent to either cam rotor face. Slots in the switch blocks laterally confine the switch elements to preserve their alignment. A raised annular bearing on the cam rotor face maintains the position of the cam rotor relative to the switch blocks. Terminal extensions from the switch elements extend perpendicular to and away from the planar faces of the cam rotor.

Abstract: A multicharacter dot matrix gas discharge display panel utilizing a plurality of connector lines which provide direct connection to the same corresponding matrix bit within each dot matrix group in the display. The gas display panel allows direct addressing of each bit to achieve high luminescence and viewability. The display has very high resolution. The display also incorporates means for positioning each dot matrix group in such a manner to closely border adjacent dot matrix group, so that the overall display dimension is decreased for a multicharacter dot matrix display panel.

Abstract: In a circuit for use with a multi-character alphanumeric gas discharge display tube in multiplex operation, each of the character locations is provided with a resistor between its keep-alive cathode and ground and an anode driver transistor connected in series circuit relation with each of the anodes. A switching transistor is connected to each of the resistors to shunt the resistors sequentially in response to receipt of multiplexed logic pulses. The shunting of a given resistor renders the anode driver transistor of an adjacent character conductive in response thereto.

Abstract: A secondary seal arrangement for use in a rotor to ensure the retention of the fluid sample within the test tube cavity of the rotor during high speed centrifugation in an ultracentrifuge. The secondary seal arrangement acts in cooperation with both a spacer member over the centrifuge tube and a sealing plug for the rotor cavity to provide a seal of the cavity over the test tube to reduce the possibility of escape of any fluid which may inadvertently exit the centrifuge tube itself. The secondary seal is positioned within the rotor tube cavity above the capping seal for the centrifuge tube to provide a closure of the rotor tube cavity above the centrifuge tube.