Abstract: The heater shutdown circuit is connected between an electric current source and a heating element in an electric heater and is operable to shut off the flow of current to the heating element when the heating element reaches a predetermined temperature and to maintain the flow of current shut off after the heating element cools to a temperature below the predetermined temperature. The heater shutdown circuit will maintain the electric current shut off until the heater shutdown circuit is disconnected from the current source for a predetermined period of time after which the heater shutdown circuit can be re-energized. The heater shutdown circuit includes a control circuit connected to the current source, a switching circuit coupled between the control circuit and the heating element, and a current sensing circuit coupled between the heating element and the junction between the control circuit and the switching circuit.

Abstract: The device comprises a body member having a liquid reservoir therein, a manually operable pump in communication with the reservoir, and an applicator post mounted on the pump. A metered amount of liquid is applied to the inner surface of a portion of a tubular member by manually placing the tubular member portion over the applicator post and then pressing inwardly of the device.

Abstract: An apparatus and method for deriving an oxygen association curve for a blood sample wherein the sample is placed on a transparent support and is covered by a gas-permeable membrane element. The support is mounted in a gas treatment chamber with transparent windows on opposite sides of the support to provide an optical path through the support normal to the sample. Radiant energy is directed along this optical path, said radiant energy including two light frequencies, one having a wavelength at which there is substantially no change in absorbance as between oxygenated and deoxygenated blood and the other having a wavelength at which there is a relatively large change in absorbance as between oxygenated and deoxygenated blood. A controlled source of deoxygenating gas, such as nitrogen, and a controlled source of oxygen are connected to the chamber. An oxygen electrode is mounted in the chamber and generates the X component, corresponding to oxygen in the chamber, in an X-Y recorder.

Abstract: A seal-less disposable flow system for use in conjunction with a centrifugal liquid processing apparatus or the like wherein a rotor assembly for subjecting a liquid to be processed to centrifugation is rotatably mounted on a rotor drive assembly, which is rotatably mounted to a stationary base. The rotor assembly is rotatably driven in the same direction as the rotor drive assembly with a speed ratio of 2:1. The flow system includes two containers adapted for mounting on the rotor assembly and a flexible umbilical cable which extends from the containers to a location external to the apparatus by way of a passageway provided in the support shaft of the rotor assembly and guide means carried on and rotatably mounted to the rotor drive assembly to maintain liquid communication with the containers during rotation of the rotor without the use of rotating seals. A reusable leader assembly facilitates installation of the flow system in the processing apparatus.

Abstract: A temperature control assembly for a centrifugal chemical treatment apparatus of the type having a temperature monitoring thermistor and a rotor heater. The heater is energized from a power source through a solid state relay. The thermistor is connected in a temperature Wheatstone bridge which delivers a voltage signal to a digital voltmeter. The digital voltmeter generates a binary output which is compared in a computer with a digital command signal from a keyboard unit. The binary computer output is a programmed function of the difference between the keyboard digital temperature command signal and the voltmeter output. This computer output controls a variable duty cycle multivibrator stage which provides a relay-operating signal whose "on" time is in accordance with the difference between the keyboard command temperature and the digital voltmeter output signal. This operating signal is delivered to the relay via an over-temperature and failure detector receiving signals from the digital voltmeter.

Abstract: A high pressure xenon arc illuminator bulb having a sapphire window generates a broad band of ultraviolet, visible and infrared radiation extending from about 180 nanometers to about 2000 nanometers.The emitted radiation in the range from about 180 to about 200 nanometers, in passing through the oxygen in the air, causes the molecules of oxygen in the form O.sub.2 to recombine to produce ozone, O.sub.3. Ozone is toxic.In the invention, a lens barrel, which holds a sapphire condensing lens, is joined to the xenon arc illuminator bulb with a lighttight and also hermetic connection. Thus, the condensing lens is optically rigid with the illuminator bulb and the ozone formed within the lens barrel is not released to the ambient environment, even though its local concentration within the lens barrel becomes high. Furthermore, the ozone confined within the lens barrel acts as an absorption filter for all of the wavelengths in the 180 to 200 nanometer band which are capable of producing ozone.

Abstract: A rotary sample changer for a spectrofluorometer has a revolving turret base which can be indexed and which carries an interchangeable sample carrier. Different sample carriers accommodate test cells, test tubes and cuvettes of different sizes and shapes.The revolving turret base and the interchangeable rotary sample carriers are constructed of material having good thermal conductivity and rotate on a large stationary hollow axle which is thermostated by thermally controlled internal fluid circulation to act as a heat source or sink to the samples. Thus, the sample carriers can readily be interchanged without disturbing the plumbing by which the thermostatic fluid is circulated.The revolving turret base is detented at the stations to which it is indexed without kinematic ambiguity and without application of any cocking force. Two spring biased ball detents, symmetrically spaced 180.degree. about the axis of rotation, are provided.

Abstract: In a recording spectrophotometer the ordinate of the plotter-scriber is controlled by the output of a photomultiplier while the abscissa of the plotter-scriber is controlled by a selectable mode manually adjusted controller.In one mode, the controller furnishes a time base signal of selected rate of change, so that the abscissa of the plotter-scriber varies with the passage of time in accordance with said rate of change.In aother mode, the controller furnishes a stepping signal of selected periodicity, for application to a stepping motor, which changes the wavelength adjustment of the spectrophotometer at a rate determined by the selected periodicity. The spectrophotometer furnishes to the plotter-scriber an analog voltge varying with the instantaneous wavelength setting of the spectrophotometer, so that the abscissa of the plotter-scriber correspondingly varies with the instantaneous value of the wavelength.

Abstract: An electric heating element assembly includes a solderless fitting for sealably securing a sheathed heating element through an aperture in a container wall or bulkhead, such as in a dishwasher or the like. The fitting includes a cylindrical sleeve positioned over the sheath of the heating element and through the aperture. A radial flange on the fitting is drawn tight against a gasket and the wall by means of a fastener on the outside surface of the sleeve to secure a watertight seal between the fitting and the wall. The sleeve is attached to the sheath by means of an annular lip on the face of the flange, circumferential portions of this lip being axially compressed during assembly so as to radially-inwardly deform corresponding circumferential portions of the sleeve and the sheath to obtain a rotationally-locked liquid-sealing engagement therebetween.

Abstract: A terminal housing for surface-type resistance heating elements includes interlocking housing sections which snap together to form compartments in which connections to the heating elements are mechanically and electrically protected. The use of identical housing sections with integral locking and strain relief provisions allows the terminal housing to be used with a wide variety of types of connections without the need for a large inventory of components.

Abstract: Disclosed herein is an improved electronic control system for the autoclaving sequence of a kidney dialysis machine, during which water is circulated at high temperature and pressure to clean and sterilize the machine. The circuit ensures that the machine will be autoclaved for a minimum period of time, such as 20 minutes, measured only while the temperature is above a minimum, such as 120.degree. centigrade. The circuit will remember the time of autoclaving previous to a power interruption, and will continue to time the autoclaving function only when the temperature has again exceeded the set minimum. Once an autoclaving sequence is initiated, the circuit prevents normal use of the machine until the sequence is completed. During the autoclave timing sequence, the kidney by-pass solenoid is energized and de-energized on a 50% duty cycle to make sure all flow paths in the machine are cleaned and sterilized.

Abstract: A lubrication system for a centrifugal liquid processing apparatus or the like having a bearing subject to operation in a centrifugal force field includes a reservoir wherein a quantity of fluid lubricant to be applied to the bearing is contained, an accumulator for receiving lubricant from the bearing, a first flow path from the reservoir through the bearing to the accumulator, and a second flow path from the accumulator to the reservoir. During operation of the apparatus lubricant is forced by the centrifugal force field to flow along the first flow path from the reservoir, through the bearing and into the accumulator under pressure. When the apparatus is stopped, lubricant is forced to return from the accumulator along the second flow path to the reservoir. An orifice is provided in the first flow path to control the flow and pressure of the lubricant within the bearing, and check valves are provided to restrict the lubricant to a circulating route through the bearing.

Abstract: The attachment is easily replaced, is flexible and elongated, and is adapted to be inserted into a tank for heating a liquid through an opening provided in the metal shell of the tank for mounting an electric immersion heater in the tank. The attachment includes a chain of metal segments which are interconnected by flexible metal wire and which are anodic to the metal shell, and includes a clamp for releasably, and electrically and mechanically, connecting one end of the chain of segments to the sheathed and grounded legs of the immersion heater.

Abstract: The noisy amplified signal from a photoelectric device is passed through an electronic low-pass filter before having its direct current component read on a meter. The cut-off frequency of the low-pass filter is adjusted in known manner by rotation of a control knob, so as to suitably match the cut-off frequency to the noisiness of the signal with a view towards speeding up the stabilization of the meter reading. To overcome the sluggishness of the system, the same control knob is briefly pushed, thereby overriding the low pass control. The method of using the system to speed up meter reading is described.

Abstract: Method of measuring the oxygen association state of blood samples, which includes the steps of disposing a blood sample within a blood-receiving receptacle, providing a controlled atmosphere chamber, incubating the sample by placing it in the chamber and controlling said atmosphere therein so as to maintain the humidity, temperature, and carbon dioxide content of the atmosphere at substantially constant levels, and thereafter analyzing the sample by changing the concentration of oxygen in said chamber from time to time while observing the changes of oxygen association of the sample with respect to the concentration of oxygen within the chamber.An apparatus which includes two sample holders receiving slides adapted to position the samples in the chamber in incubating and analyzing position, respectively.

Abstract: A hinge bar and product assembly for use in manufacture of partial dentures including a hinge bar having a cylindrical end surface thereon adapted to be received internal of a mating support member attached to supporting natural teeth. The cylindrical end surface of the hinge bar closely fitting the internal mating surfaces of the support therefor and having at the top portion thereof a stop surface to limit movement of the bar with respect to the support and having at the other end thereof notches which are adapted to receive an attaching member to be cast therearound, providing an extremely compact hinge assembly providing exceptional strength in preventing horizontal or lateral movement of the hinge bar thereof with respect to the support and presenting no pockets and/or recesses in which food or moisture can collect.