With Means To Supply The Gas Patents (Class 250/379)
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Patent number: 4862005Abstract: An apparatus for detecting radioactive contamination in hand-held objects, such as tools used to service a nuclear power facility, is disclosed herein. The apparatus generally comprises a radiation detector assembly having a gas-flow proportional detector, and a platform assembly formed from a perforated sheet of rigid material disposed over the topside of the detector for both supporting the hand-holdable objects and uniformly spacing the object from the detector. The radiation detector assembly is contained within a shielding cabinet having an access opening that is offset out of alignment with the top side of the detector for allowing an operator to deposit and withdraw an object onto and off of the platform. The walls of the shielding cabinet include pocket-like mounting assemblies for releasably holding one or more sheets of lead shielding material so that the amount of background radiation-reducing shielding may be advantageously adjusted.Type: GrantFiled: June 2, 1988Date of Patent: August 29, 1989Assignee: Westinghouse Electric Corp.Inventors: Alfred N. Johnson, Martin D. Humphrey
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Patent number: 4837440Abstract: Aerosol particles, resulting from the combustion of organic substances with insufficient oxygen supply, usually contain toxic, higher hydrocarbonic substances (e.g. tar) on their surface. These substances, e.g. tar, has the property to be photoelectrically more active than other substances contained in the atmosphere. In the method and apparatus according to the invention an aerosol, i.e. the carrier gas containing the particles to be characterized, is used which has been brought to at least one predetermined temperature sufficient for evaporation or decomposition or preventing condensation of molecules on particles of said aerosol that quench or enhance photoelectric activity. Such aerosol is exposed to electromagnetic radiation and, thereby, activated to electron emission. Thereafter the charge of the photoelectrically positively charged particles is determined by means of size selective filter means which are connected to current or charge measuring equipment.Type: GrantFiled: November 3, 1986Date of Patent: June 6, 1989Assignee: Matter & Siegmann AGInventors: Heinz Burtscher, Adnreas Schmidt-Otl, Hans-Christoph Siegmann
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Patent number: 4820925Abstract: A housing assembly for use with a room air monitor for simultaneous collection and counting of suspended particles includes a casing containing a combination detector-preamplifier system at one end, a filter system at the other end, and an air flow system consisting of an air inlet formed in the casing between the detector-preamplifier system and the filter system and an air passageway extending from the air inlet through the casing and out the end opposite the detector-preamplifier combination. The filter system collects suspended particles transported directly through the housing by means of the air flow system, and these particles are detected and examined for radioactivity by the detector-preThe U.S. Government has rights in this invention pursuant to Contract No. DE-AC04-76DP03533 between the Department of Energy and Rockwell International Corporation.Type: GrantFiled: March 23, 1987Date of Patent: April 11, 1989Assignee: The United States of America as represented by the United States Department of EnergyInventors: David K. Balmer, William H. Tyree
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Patent number: 4804846Abstract: An improved photoionization detector has a sweep gas inlet which is used to introduce sweep gas near the window of the detector's ultraviolet lamp. The detector's chamber has a vent which allows selective removal of spurious analyte. The detector is adapted to have directly mounted on it, a second detector. Sweep gas used to keep analyte away from the window may be used as a reagent in the second detector. In addition, a means for regulating the ionization lamp voltage is disclosed which prolongs lamp life expectancy.Type: GrantFiled: December 4, 1987Date of Patent: February 14, 1989Assignee: O. I. CorporationInventor: Randall C. Hall
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Patent number: 4789783Abstract: A discharge ionization detector has a detector body with first and second chambers and an interconnecting aperture passageway. A glow discharge emission in the first chamber is directed through the aperture to cause ionization of column effluent species in the second chamber. A polarizing electrode creates an electric field to cause acceleration of ionized species toward a collector electrode coupled to an electrometer. The detector body is of an electrically-conductive material and is coupled to ground potential to reduce entry of glow discharge-produced electrons into the second chamber.Type: GrantFiled: April 2, 1987Date of Patent: December 6, 1988Inventor: Robert D. Cook
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Patent number: 4775795Abstract: A method for detecting very small concentrations of gases in gas mixtures passed as a gas stream through a measuring cell having a chamber through which the gas stream flows through, a drift zone provided between an inlet and an outlet of the chamber, a gas stream ionizing radiation source located at the inlet of the drift zone, a collector electrode located at the outlet of the drift zone, a grid consisting of two groups of parallel wires located in the drift zone current adjacent grid wires are supplied with different electrical voltages and whereat an AC voltage of adjustable frequency is fed to the two groups of grid wires, and a measuring apparatus for detecting the collector current, including the steps of inducing the movement of the ions through the drift zone by means of a ventilator which generates a controlled gas flow to the collector electrode, periodically changing the frequency of the AC voltage applied to the groups of grid wires either continuously or stepwise, simultaneously measuring the coType: GrantFiled: February 12, 1987Date of Patent: October 4, 1988Assignee: Honeywell-Elac-Nautik GmbHInventors: Karl-Ernst Biehl, Egon Tyssen, Conrad G. von Roedern
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Patent number: 4733086Abstract: A thermal electron source suitable for use in an electron capture detector comprises a source of stable ultra-violet light, an ultra-violet transparent support member (20,31) located in the path of the ultra-violet light (41) and a thin photo-emissive metallic layer (1A, 24, 33) coated over the surface of the support member remote from the source. In one form the source is a cylindrical mercury vapor lamp (1) with the photo-emissive layer coated directly on the lamp. The coated lamp may then be enclosed within a cylindrical anode (8) with a gas flow between them and the electrical current is measured between the anode and cathode. In an alternative arrangement a planar geometrical assembly is provided. Preferably the photo-emissive material is gold and the carrier gas is an argon-methane mixture.Type: GrantFiled: March 7, 1986Date of Patent: March 22, 1988Assignee: The Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern IrelandInventor: Peter G. Simmonds
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Patent number: 4721858Abstract: Method and apparatus for differentiating organic compounds based on their electron affinity. An electron capture detector cell (ECD) is operated at pressures ranging from atmospheric to less than 1 torr. Through variation of the pressure within the ECD cell, the organic compounds are induced to either capture or emit electrons. Differentiation of isomeric compounds can be obtianed when, at a given pressure, one isomer is in the emission mode and the other is in the capture mode. Output of the ECD is recorded by chromatogram. The invention also includes a method for obtaining the zero-crossing pressure of a compound, defined as the pressure at which the competing emission and capture reactions are balanced and which may be correlated to the electron affinity of a compound.Type: GrantFiled: April 21, 1986Date of Patent: January 26, 1988Assignee: The United States of America as represented by the United States Department of EnergyInventors: Michelle V. Buchanan, Marcus B. Wise
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Patent number: 4705948Abstract: A helium ionization detector for gas chromatography is operated in a constant current, pulse-modulated mode by configuring the detector, electrometer and a high voltage pulser in a closed-loop control system. The detector current is maintained at a fixed level by varying the frequency of fixed-width, high-voltage bias pulses applied to the detector. An output signal proportional to the pulse frequency is produced which is indicative of the charge collected for a detected species.Type: GrantFiled: February 24, 1986Date of Patent: November 10, 1987Assignee: The United States of America as represented by the United States Department of EnergyInventors: Roswitha S. Ramsey, Richard A. Todd
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Patent number: 4684807Abstract: A small volume electron capture detector has a cylindrical cell 120 inside which there is provided a generally funnel-shaped insert structure 130 having a cup-shaped section and a cylindrical section. The rims of the cup-shaped section nearly touch the inner walls of the cell 120 so as to separate the active volume from the areas at the top corners of the cell 120 which are not actively swept by the carrier gas, thus reducing the tailing of chromatographic peaks.Type: GrantFiled: May 13, 1985Date of Patent: August 4, 1987Assignee: Varian Associates, Inc.Inventor: Gregory J. Wells
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Patent number: 4680472Abstract: When using an electron capture detector for the molecular identification of electrophilic compounds, the sensitivity of the detector is made reproducible by controlling the voltage or frequency of the pulses applied to it to maintain a reference current whose set value is produced automatically by the device after determination of the characteristics of the state of the detector, namely a so-called saturation current CM and a so-called spontaneous current CS, according to a law of proportionality between these two currents.In addition, knowledge of these state characteristics gives information on the physical and physicochemical anomalies of the analysis device having an effect on the sensitivity of the detector, and consequently enables them to be remedied.Type: GrantFiled: January 14, 1986Date of Patent: July 14, 1987Assignee: Giravions DorandInventor: Claude Mendes
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Patent number: 4651008Abstract: An electron capture detector for use with a capillary column is provided with a sample inlet comprising a tubular anode through which sample molecules and a make-up gas are introduced into the detector cell. The tubular anode has side ports for producing a plug-like flow inside the cell. The inner surface of the anode is protected by an insulating tube so that the capillary column can be extended to a point beyond the side ports without the fear of its electrical contact with the anode. This allows the sample molecules to flow nearly entirely in the center section of the cell. The peripheral regions of the cell where a radioactive foil is disposed is swept nearly entirely by the make-up gas entering the cell through the side ports. This has the effects of reducing sample dilution by the make-up gas and sample loss due to contact with the detector walls.Type: GrantFiled: September 6, 1983Date of Patent: March 17, 1987Assignee: Varian Associates, Inc.Inventor: Gregory J. Wells
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Patent number: 4585932Abstract: A system for monitoring potentially hazardous conditions in an area. The monitor system provides a continuous check of the atmosphere in a given area for nuclear radiation hazard and for combustion hazard. When a predetermined radiation level or combustion condition occurs in the area an alarm is activated which indicates the particular kind of danger existing. A small bomb calorimeter housing or vessel supports and houses a radiation sensor and a combustion sensor. Detection circuitry responds to the radiation and combustion sensors to provide an output signal when a predetermined, dangerous threshold condition exists in the area. A screen capacitor, electroscope, and a periodic charging circuit comprise the radiation hazard detection circuitry. A reflex surge generator comprised of a sparking circuit and a spark gap in conjunction with a resistance thermometer detector provide the fire hazard circuitry. Indicator or annunciator circuitry coupled to the detectors disclose the status of the two circuits.Type: GrantFiled: August 6, 1984Date of Patent: April 29, 1986Inventors: Thomas G. Roberts, Thomas E. Honeycutt
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Patent number: 4567368Abstract: In operating an ECD in constant current mode, two pulses are implemented either to the same electrode or to separate electrodes, thereby dispersing the space charge sheath near the collector electrode and thus enhancing electron extraction at high frequencies. This has the effect of extending both the dynamic range and the linear dynamic range.Type: GrantFiled: January 19, 1984Date of Patent: January 28, 1986Assignee: Varian Associates, Inc.Inventors: Gregory J. Wells, Richard K. Simon
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Patent number: 4538066Abstract: Metastable ionization detectors used for chromatographic analysis usually employ a fixed high voltage for the ionization potential. For this reason, the operating range is limited to about three orders of magnitude. By use of the technique disclosed in the instant invention, operating ranges of about nine orders of magnitude are obtained.The output current from a metastable ionization detector (MID) is applied to a modulation voltage circuit. An adjustment is made to balance out the background current, and an output current, above background, is applied to an input of a strip chart recorder. For low level concentrations, i.e., low detected output current, the ionization potential will be at a maximum and the metastable ionization detector will operate at its most sensitive level.Type: GrantFiled: February 22, 1984Date of Patent: August 27, 1985Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space AdministrationInventors: Glenn C. Carle, Daniel R. Kojiro, Donald E. Humphry
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Patent number: 4527064Abstract: A method and apparatus for detecting and imaging alpha particles sources is described. A conducting coated high voltage electrode (1) and a tungsten wire grid (2) constitute a diode configuration discharge generator for electrons dislodged from atoms or molecules located in between these electrodes when struck by alpha particles from a source (3) to be quantitatively or qualitatively analyzed. A thin polyester film window (4) allows the alpha particles to pass into the gas enclosure and the combination of the glass electrode, grid and window is light transparent such that the details of the source which is imaged with high resolution and sensitivity by the sparks produced can be observed visually as well. The source can be viewed directly, electronically counted or integrated over time using photographic methods.Type: GrantFiled: July 5, 1983Date of Patent: July 2, 1985Assignee: The United States of America as represented by the United States Department of EnergyInventor: David F. Anderson
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Patent number: 4445037Abstract: A conventional Kanne tritium monitor has been redesigned to reduce its sensitivity to such contaminants as tritiated water vapor and tritiated oil. The high voltage electrode has been replaced by a wire cylinder and the collector electrode has been reduced in diameter. The area sensitive to contamination has thereby been reduced by about a factor of forty while the overall apparatus sensitivity and operation has not been affected. The design allows for in situ decontamination of the chambers, if necessary.Type: GrantFiled: January 27, 1981Date of Patent: April 24, 1984Assignee: The United States of America as represented by the United States Department of EnergyInventor: David F. Anderson
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Patent number: 4426580Abstract: The present invention is directed to a detection device comprising: (1) an entrance chamber, (2) a central chamber, and (3) an exit chamber. The central chamber includes an ionizing gas, anode, and means for connecting the anode with an external power supply and pulse counter.Type: GrantFiled: May 18, 1983Date of Patent: January 17, 1984Assignee: The United States of America as represented by the United States Department of EnergyInventor: Jay E. Smith
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Patent number: 4388411Abstract: The invention relates to apparatus for detecting a constituent gas in a gas flow. Means is provided for removing the constituent gas from a sample flow and directing this sample flow together with a reference flow containing the constituent gas through an equilibrator means wherein contaminants can be removed before the sample gas and the reference gas are compared in detector means, for example, an electron capture detector. The apparatus and method are also applicable to the detection of a liquid in a flow thereof.Type: GrantFiled: April 29, 1981Date of Patent: June 14, 1983Assignee: Hewlett-Packard CompanyInventor: James E. Lovelock
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Patent number: 4345154Abstract: An ionization detector unit innovatively adapted to provide mobility to the nit and to render it especially suitable for convenient "field-use" in point-source sampling and monitoring of the compositional characteristics of a gaseous medium such as, for example, the ambient atmosphere, and in emitting a discernible electrical signal which in response to a perceptible change in the compositional characteristics in the medium being monitored by the detector will be altered sufficiently to activate, or trigger, a suitable alarm or warning mechanism.Type: GrantFiled: May 18, 1981Date of Patent: August 17, 1982Assignee: The United States of America as represented by the Secretary of the ArmyInventor: Augustus S. Bainbridge
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Patent number: 4304997Abstract: An electron capture detector in which a thermionic source such as a filament provides electrons for the reaction in a source chamber having a port that connects to a detection chamber having a collector. Guard gas is introduced into the source chamber and sample gas into the detection chamber, and an exhaust port is provided in the detection chamber.Type: GrantFiled: February 27, 1979Date of Patent: December 8, 1981Assignee: Hewlett-Packard CompanyInventors: James J. Sullivan, William P. Kruger, Douglass McManigill, Armand P. Neukermans
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Patent number: 4264817Abstract: An electron capture detector in which electrons for the reaction are supplied by a filament in a cylinder through which guard gas is passed. Apertures in the cylinder permit electrons from the filament to pass into an annular space surrounding the cylinder and between it and a collector. Sample gas is passed between the aperture and the collector, the pressures being such as to be capable of minimizing the diffusion of sample gas to the filament.Type: GrantFiled: February 27, 1979Date of Patent: April 28, 1981Assignee: Hewlett-Packard CompanyInventors: Armand P. Neukermans, Douglass McManigill
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Patent number: 4156813Abstract: A detector module for use in a gas monitor assembly to measure changes in electron flow resulting from absorption of electrons in an electron capture gas includes an internal housing for containing a radioactive source and electrodes suitably spaced apart to permit gas flow therepast. The internal housing along with couplings for interconnection with a gas flow source, a gas receiver and suitable electronic receiver means are disposed within a detector housing having integrally attachable closure means, the detector housing and closure means providing shielding for the radioactive source while being adapted in combination to prevent operating access to the couplings in order to prevent accidental or undesired exposure of the internal housing and radioactive source.Type: GrantFiled: July 25, 1977Date of Patent: May 29, 1979Assignee: Systems, Science and SoftwareInventors: Brian S. Flanagan, Phillip L. Turner, Richard D. Broce, Peter L. Lagus
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Patent number: 4149109Abstract: A location- or positionally-sensitive proportional counter tube of high resolution having a trough-shaped cathode in a counting chamber. A resiliently elastic wire forming the anode extends longitudinally through the counting chamber. Suitable fastening arrangements engage the ends of the wire so as to mount the wire equidistantly from the side walls of the cathode trough and in electrical communication with the input resistor of a preamplifier. The counting chamber is an openable high-pressure chamber with inlet and outlet apertures for a pressurized counter tube gas.Type: GrantFiled: October 27, 1977Date of Patent: April 10, 1979Assignee: M. Braun GmbHInventors: Werner Kreutz, Manfred Henne, Jurgen Fritz
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Patent number: 4129782Abstract: A curved location- or positionally-sensitive proportional counter tube having a trough-shaped cathode in a counting chamber. A curved resiliently elastic wire forming the anode extends longitudinally through the curved counting chamber in conformance with the curvature of the latter. Suitable fastening arrangements engage the ends of the wire so as to mount the wire in asymmetrical relationship to a counter tube window and equidistantly from the side walls of the cathode trough.Type: GrantFiled: August 25, 1977Date of Patent: December 12, 1978Assignee: M. Braun GmbHInventor: Werner Kreutz
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Patent number: 4117332Abstract: A circuit improvement is disclosed for use in an electron capture detector of the type including an electron capture cell, means for applying polarization pulses to the cell to derive a cell current, means for varying the pulse rate to maintain the cell current constant, and means for converting the pulse frequency to an analog signal indicative of the concentration of an electron-capturing component.Type: GrantFiled: February 26, 1976Date of Patent: September 26, 1978Assignee: Varian Associates, Inc.Inventors: John Robert Felton, Russell S. Gutow, Jr.
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Patent number: 3935464Abstract: A detector for ionizing radiation comprising a generally cylindrical enclosure which contains an ionizable gas, a central wire which with a peripheral wall constitute the electrodes of the device, and a window to permit entry of ionizing radiation. With appropriate potentials applied to the central wire and peripheral wall, ionizing radiation produces electrons which are attracted to the central wire and positive ions which are attracted to the peripheral wall in proportion to the intensity of the radiation. One or more auxiliary electrodes are provided which extend parallel to and between the central electrode and the peripheral wall. An appropriate potential is applied to this auxiliary electrode to neutralize the positive ions.Type: GrantFiled: December 17, 1973Date of Patent: January 27, 1976Inventor: William P. Zingaro