Abstract: An analysis system of the centrifugal analyzer type has an analysis station for receiving a multi-cuvette rotor unit with means at the analysis station for performing analyses on the contents of a plurality of cuvettes of a multi-cuvette rotor unit concurrently, and means at the analysis station for spinning the rotor unit. Rotor hold down means at the analysis station includes disc structure for seating engagement with loading ports of the rotor unit at the analysis station, a disc support for allowing the disc to rotate freely in alignment with the drive axis of the drive mechanism, and mechanical means for moving the freely rotatable disc between an operative position in seating engagement with the loading ports of the rotor unit and a second position spaced from the seated position.

Abstract: An analysis system has a first region in which sample materials are stored at an appropriate storage temperature and an analysis region which is maintained at a controlled and stabilized temperature higher than the temperature of the first region. Transfer mechanism for transferring a quantity of sample material from the first region for loading into an analysis cuvette in the analysis region includes a liquid handling probe that is mounted on a probe transport carriage, and a drive for moving the transport carriage between the first and second regions. The transport carriage includes a storage chamber connected to the liquid handling probe, thermal energy supplying means in heat exchange relation with the storage chamber, and thermal sensor means carried by the transport carriage. Means responsive to the thermal sensor supplies thermal energy to the transport carriage to maintain the storage chamber at substantially the same temperature as the analysis region.

Abstract: A system for analyzing a biological fluid or the like includes a series flow loop that extends between an inlet valve array and an outlet valve array. The flow loop includes an analysis region to which a measuring system is connected in sensing relation and an accumulator chamber connected to the outlet of the analysis region. The inlet valve array is arranged to selectively and alternately connect a sample inlet port and an auxiliary fluid reservoir to the flow loop while the outlet valve array is arranged to selectively connect a controlled source of reduced pressure to the flow loop.

Abstract: A preheater suitable for a laboratory furnace provides improved furnace temperature uniformity and atmosphere control. The preheater comprises a rectangular chamber which is adapted to be placed in the bottom of the furnace chamber. The preheater includes a pair of longitudinal passageways on opposite sides of the preheater chamber. There is a plurality of perforations in the top wall at one end of the preheater and along each passageway for distributing preheated air or other gas into the furnace chamber. In a preferred embodiment, the preheater is made of stainless steel, and the preheater chamber contains stainless steel wool which aids in heat transfer.

Abstract: A self-sealing ceramic crucible and lid combination suitable for proximate analysis of coal or coke samples. The combination comprises a generally cylindrical crucible vessel having a substantially flat outside bottom surface one one end and being open on the other end, the wall of the vessel terminating at its open end in a rim which is finished circumferentially for sealing with the lid. The inside bottom surface is also preferably substantially flat. The lid member is generally cup-shaped and has a circular top wall and a depending circumferential skirt portion, the upper surface of the top wall being generally flat, the inside diameter of the top wall being slightly greater than the outside diameter of the crucible vessel, such that when the lid member is placed on the crucible vessel, the lower surface of the top wall which has a finished annular recess rests on the rim of the crucible, and the skirt of the lid member extends downwardy along the wall of the crucible and terminates in a circular edge.

Abstract: A spark source circuit has a discharge circuit including reactive means connected in circuit between a capacitor and an analytical spark gap and switching means for effectively removing the capacitor from the discharge circuit after an initial flow of current through the spark gap so that the current flow through the spark gap is essentially unidirectional. At the start of the capacitor discharge, the discharge circuit is essentially of the classical RLC oscillatory discharge type; and the switching action converts the discharge circuit to essentially a classical RL discharge type circuit for the remainder of the spark discharge. The circuit is simple and efficient, permits use of ceramic capacitors, and may be housed in a sealed enclosure.

Abstract: An improved method of potentiometrically titrating a sample to an unknown endpoint or endpoints is disclosed. The method includes delivering a titrant to the sample until an endpoint or endpoints are reached, while continuously monitoring the volume of the titrant delivered to the sample and continuously monitoring the potential of the sample during titration. The improvement in the method is accurately determining the endpoint or endpoints by establishing a substantially constant rate of change in sample potential during titration proximate to the endpoint or endpoints and maintaining the established rate of change in sample potential by adjusting the rate of delivery of the titrant.

Abstract: The susceptibility of microorganisms to various antibiotics is determined by propagating microorganisms in the presence of different concentrations of various antibiotics in a plurality of test chambers, using a serial dilution technique. Microgram quantities of each antibiotic are retained in a graduated series of concentrations in each of a series of test chambers by poly(vinyl pyrrolidone) as a water-soluble bulking agent and carrier, in frozen-dried form.

Abstract: This invention relates to apparatus for processing histological tissue specimens and the method of processing the specimens utilizing the apparatus. More particularly, the apparatus provides means for automatically processing the specimens in a single container by sequentially introducing and removing solvents and/or paraffin into and from said container.

Abstract: Indirect test for the qualitative and quantitative determination of immunoglobulins, G, A or M in human body fluid utilizing immuoglobulins (IgG, IgA and IgM) chemically coupled to latex carrier particles as the reagent.

Abstract: Indirect test for the qualitative and quantitative determination of the presence of fibrinogen degradation products in human serum or urine utilizing the purified D and E fragments of fibrinogen chemically coupled to latex carrier particles as the reagent.

Abstract: The susceptibility of microorganisms to various antibiotics is determined by propagating microorganisms in the presence of different concentrations of the antibiotic in a plurality of test wells or chambers, in a culture test plate which has a row of rectangular wells for photomechanical optical reading. The test plate is disposable of one piece plastic, with a separate protective cover, and readily moldable. A series of concentrations of a particular antibiotic are prepackaged and stored dry in the test wells of a single test plate. Various antibiotics in test plates may be stacked for convenience in handling and incubation.

Abstract: The dispensing apparatus includes a syringe having a plunger therein and appropriate inlet and discharge openings associated therewith. Two cams are positioned in spaced relationship with a connecting rod mounted to an eccentric of each cam and pivotally to the plunger in the syringe. Motor elements cause rotation of one of the cams with the second cam acting as the fixed pivot point to move the plunger through a first distance. Rotation of the second cam with the first cam acting as the fixed pivot point causes the plunger to move through a second distance. Two liquid volumes are, therefore, dispensed from a single syringe in which one-half cycle of rotation of either cam acts to fill the syringe and the other half cycle acts to discharge the syringe. A multistation dispenser is provided by using a plurality of syringes and connecting two such cam assemblies to a cross bar which causes simultaneous reciprocation of the various plungers associated with the plurality of syringes.

Abstract: An improved incubator includes a heated door which increases temperature uniformity inside the incubator.

Abstract: Our system for determining the sulfur content of a sample includes combusting the sample to form a gas in which the sulfur is converted primarily to sulfur dioxide in known ratio with the sulfur trioxide. The gas sample is passed into a reaction vessel containing a substantially pyridine solvent. The sulfur dioxide is scrubbed from the sample (trapping) via a binding action with the pyridine. The bound sulfur dioxide is titrated with elemental iodine in the presence of alcohol and excess water. The trapping and titration sequence can be simultaneous and continuous. A polarized electrode pair is preferably employed as the detection means with the end point determination occurring when the electrodes become current conducting in the presence of excess iodine. The titrant volume is then converted to a sulfur analysis by standard means. The apparatus is disclosed for carrying out the method.

Abstract: A humidifier for conditioning fluid for delivery to a test chamber, such as an incubator, includes means for automatically regulating the quantity, level and temperature of a body of water through which mixed gases, such as air and CO.sub.2, are bubbled to entrain moisture in the gases. The water is heated to below its boiling point. The relative humidity of the saturated mixture delivered to the test chamber is usually at least 90% at temperatures between about 30.degree. - 60.degree.C.

Abstract: A spark source is disclosed having an analytical spark gap, a capacitor, a power supply for charging the capacitor, and an electronic switching tube connected in a series circuit between the capacitor and the spark gap. When the tube is rendered conductive by a triggering pulse or other signal, the capacitor is discharged through the spark gap and the switching tube, which carries the entire discharge current.