Abstract: Apparatus for determining the concentration of the various components of a sample, which includes a spectrophotometer for receiving a sample to be analyzed and performing extinctions of the sample at a plurality of preselected wavelengths to form a sample spectrum; memory devices for storing a standard spectra of each of the individual components; circuitry for weighting the sample spectrum at different wavelengths in conformity with each of the standard spectra and providing estimated values of the concentrations of the components from the sample spectra thus weighted; circuitry for reconstructing the sample spectrum as a linear combination of the estimated values of the concentrations and the standard spectra; a subtractor for forming a difference spectrum from the sample spectrum and the reconstructed sample spectrum; circuitry for weighting the difference spectrum at different wavelengths in conformity with each of the standard spectra and providing corrective values of the concentrations of the component

Abstract: The fluid flow switching apparatus includes a housing defining a chamber, a bore in communication with the chamber, fluid inlet and outlet ports respectively in communication with the chamber and bore, and a valve body movable within the chamber and carrying a sealing means for sealing about the bore. The valve body carries a pin which projects laterally into a cam track formed in the housing and which serves to releasably lock the valve body in a position enabling flow between the inlet and outlet ports through the chamber and bore and in a valve closed position preventing flow between the inlet and outlet ports. The valve body is movable manually between the valve open and closed positions by consecutive depressions of a push key connected to the valve body.

Abstract: Closure for a sample vial utilized to introduce sample into a gas chromatograph in accordance with the head space method. The closure includes a flexible disc for closing the opening through the neck of the vial and overlying the margin of the neck about the vial opening. A cap having a central aperture defining an annular shoulder about the aperture overlies the disc. The cap has an annular depending skirt encompassing the disc for clamping about the neck of the vial to retain the disc and the cap on the vial. A portion of the closure is deformable for venting the vial to atmosphere in response to a pressure within the vial when the closure is applied thereto in excess of a predetermined pressure.

Abstract: The invention relates to a spectrometer including a rotatable dispersive element, a stepping motor for varying the angular position of said dispersive element, a program transmitter for controlling said stepping motor, a timing generator and a recording instrument.

Abstract: Gaseous measuring samples like element hydrides are generated from liquid samples by reacting the same with reducing reagents in a reactor. In the reactor a countercurrent of inert gas strips the volatile reduction products from the reactor to convey the products to the measuring cell of an analytical measuring instrument. Various embodiments of the apparatus automatically controlling the supply of liquid sample and reagents to the reactor are disclosed such as mechanically or pneumatically controlled pumps. In each measuring cycle the reactor and respective components are washed to prevent contamination of succeeding samples; also, analytical determination of blank values as well as reference values can be included in each measuring cycle.

Abstract: Atomic absorption spectrometer sample supply apparatus for producing a gaseous sample for analysis and for transferring the sample to the atomic measuring cuvette. The sample supply is in a sealed vessel and, by directing the flow of a pressurized inert gas, the sealed sample vessel is first purged of contaminating air, a volatilizing reagent is forced by inert gas pressure into the sample, and a small specimen of the gaseous sample is transferred by gas pressure into the cuvette inlet tube.

Abstract: An automatic sampling apparatus for withdrawing samples from a continuously flowing liquid for analysis by a flameless atomic absorption spectrometer includes a sample vessel which, at predetermined times, receives pumped samples of the liquid to be tested, a neutral dilutant liquid, or a calibrated liquid for recalibrating the spectrometer system. A probe having a pipette-like tip is mechanically actuated to dip into the sample vessel and an intake and dispensing pump connected to the probe draws a small sample into the probe tip whereupon the probe mechanism lifts and rotates the probe and inserts the tip into the graphite atomizer tube of the atomic absorption spectrometer. The probe mechanism then returns the probe where it is first flushed with a flushing liquid pumped through the probe and is then returned to the sample vessel to draw the next test sample.

Abstract: Inaccuracies resulting from measuring the internal temperature of absorption spectrophotometer graphite tube furnaces by pyrometric measurements of a spot on the external surface of the graphite tube are overcome by a novel arrangement in which the pyrometer detector measures the interior through the tube end and at an angle that permits a view of the entire interior length without interfering with the spectrophotometer sample beam.

Abstract: Disclosed is a sample feeding apparatus having a housing defining first and second chambers sealed one from the other and a needle movable longitudinally with respect to the housing. The first and second chambers continuously receive carrier and purging gases respectively through suitable conduits. The needle has an opening normally in communication with the second chamber for continuously purging the needle. Upon application of a sample vessel to a member telescopically received about the housing, the needle is displaced through a seal into the first chamber. Carrier gas is thus provided through the needle into the head space of a sample vessel and the sample will flow to the injection block of a gas chromatograph in response to pressure compensation between the injection block and head space. Upon withdrawal of the sample vessel from below the sampling apparatus, the needle is spring returned to its initial position preventing carrier gas from flowing from the first chamber through the needle.

Abstract: A precision digital flow rate control system particularly suitable for controlling the flow of an inert gas into the atomizing furnace of an atomic absorption spectrometer. The selection of the desired flow rate is made by switching the flow through one or more of the plurality of tubes having restrictors that limit the flow according to digital steps. The flow is switched by directional control solenoid valves that direct the flow either through a flow restrictor to the atomizing furnace or through an identical flow restriction to a vent. Therefore, there will always be a constant flow through each valve and, since the inlet pressure regulator will always see a constant load, it can maintain a very constant pressure to the valves.

Abstract: The graphite sample tube used in flameless atomic spectroscopy is mounted in coaxial bores of two separated heating electrodes, each supported by a cooling jacket for carrying off the excess heat produced by the sample tube. Instead of being sealed with sealing rings, the cooling jackets contain seamless tubing that is tightly pressed in the grooves and carries a flow of suitable coolant. The tubing eliminates fluid eddies and thermal stresses which inevitably leads to coolant leaks. An additional feature is that one of the two cooling jacket housings is pivotally movable by a pneumatic actuator for easy removal of the graphite sample tubes and the inspection of the bores of the electrodes.

Abstract: A graphite tube atomizer for flameless atomic absorption spectroscopy includes a graphite tube disposed to permit passage of a measuring beam therethrough. The graphite tube is engaged at opposite ends by annular contact pieces which are coupled to a source of electrical current. The contact pieces are supported in housing portions which serve to surround the graphite tube and provide a chamber into which cooling gasses can be admitted. The cooling gasses also serve to reduce deterioration of the graphite tube. The housing portions are selectively movable either toward or away from each under the power of a drive mechanism. The housings may be urged by the drive mechanism toward each other so the contacts mounted thereon are in selectable pressure engaging contact opposite ends of the graphite tube.

Abstract: In a spectrophotometer having a cuvette, a photoelectric detector having a photosensitive surface, a light source arranged for passing a light beam through the cuvette onto the photosensitive surface, an imaging optical system arranged between the cuvette and the photosensitive surface or a rear image thereof being located in a focal plane of the optical system outside the image plane of the light source, whereby the light beam impinges on the photosensitive surface as a relatively large light spot of substantially uniform illumination and, as a result, the location and size of the light spot is not adversely affected by parallel offset, and the demands as to accuracy and alignment of the cuvette are reduced.

Abstract: The desired element in a specimen to be analyzed by atomic absorption spectroscopy is deposited in the spectroscope measuring tube in a concentrated form by first distilling away all components of the specimen that are more volatile than the element, then increasing the heat to distill off the desired element which is condensed on the cooler walls of the measuring tube while all components less volatile than the element will remain in the adjacent heated specimen crucible.

Abstract: Disclosed is an apparatus and method for using same for atomic absorption determination of volatile, thermally decomposable compounds. The test sample is converted to a gaseous sample in a reaction vessel with an inert gas atmosphere. The gaseous sample in the inert gas is then introduced into a heatable measuring cell arranged in the ray path of an atomic absorption spectrometer. To further assist decomposition, the inert gas is heated prior to entering the measuring cell.

Abstract: The combustion of hydrogen at the open ends of an atomic absorption spectrometer heated atomizing tube that is being supplied with substances or reagents containing volatile hydrides is eliminated by tube extensions of low heat conductive material that lower the temperature of the gas below its flash point.

Abstract: Method and apparatus for generating a gaseous test sample from a liquid sample and for transferring this test sample into a measuring cuvette of an atomic absorption spectrometer, in which an inert gas flow is directed through a sample vessel and into a measuring cuvette and, after the air has been displaced from the sample vessel, a reagent is added for generating a gaseous test sample, the test sample being carried into the measuring cuvette by the inert gas flow, wherein prior to the adding of the reagent, the flow rate of the inert gas flow is changed-over from a higher value to a lower value.

Abstract: The invention relates to a method and apparatus for measuring the temperature of an object within a temperature range of between about 100.degree. C and about 2700.degree. C by deriving a signal indicative of the temperature of the object from the total radiation within a limited wavelength range extending from about 8 to about 14 microns. In one form of the invention, a device is provided which includes a radiation detector, a reference member, a temperature control device for automatically maintaining the temperature of the reference member at a substantially constant value, a device for alternately directing radiation from the object and from the reference through a filter to the radiation detector, a signal processing system for receiving signals from the radiation detector and outputting a signal indicative of the temperature of the object, responsive to the difference between the radiation detected from the object and from the reference member.

Abstract: The invention relates to a graphite tube assembly for use in an atomic absorption spectrometer for measuring the flameless absorption of samples when passing a beam of radiation therethrough, which includes a graphite tube and an inner body disposed in the interior of the graphite tube, but externally of the beam of radiation when passing through the tube, said inner body extending only over a portion of the length of the graphite tube.

Abstract: An atomic absorption spectrophotometer incorporating discrimination against "background" absorption, i.e., absorption not caused by the resonant line absorption by the element being measured. The device includes a resonant line emitting source (e.g., a hollow cathode lamp) and a continuous spectrum light source (e.g., a deuterium lamp), a monochromator and a detector system. The improvement comprises a specific chopper arrangement which sequentially causes: (a) the resonant line light from the hollow cathode lamp to go to the sample path, (b) this light to go to the reference path, (c) the continuous spectrum light from the deuterium lamp to go to the reference path, and finally (d) the continuous spectrum light to go to the sample path. By comparing the light intensities during intervals (c) and (d) the effect of the background absorption can be determined and compensated for so as to determine the relationship between (a) and (b) free of the effect of such background absorption.