Dosimeter Patents (Class 436/902)
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Patent number: 8435796Abstract: A method for using of a fabric comprising a material chosen from metals, metallic alloys, polymers, inorganic compounds and mixtures thereof, which material is capable of detecting the presence of a chemical substance, for the detection of said chemical substance.Type: GrantFiled: November 16, 2010Date of Patent: May 7, 2013Assignee: Commissariat a l'Energie Atomique et aux Energies AlternativesInventors: Jean Brun, Catherine Durand, Alain Soubie
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Patent number: 5868856Abstract: A method of removing inorganic contamination from substantially the surface of a semiconductor substrate, the method comprising the steps of: reacting the inorganic contamination with at least one conversion agent, thereby converting the inorganic contamination; removing the converted inorganic contamination by subjecting it to at least one solvent agent, the solvent agent is included in a first supercritical fluid (preferably supercritical CO.sub.2); and wherein the converted inorganic contamination is more highly soluble in the solvent agent than the inorganic contamination.Type: GrantFiled: July 23, 1997Date of Patent: February 9, 1999Assignee: Texas Instruments IncorporatedInventors: Monte A. Douglas, Allen C. Templeton
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Patent number: 5747348Abstract: A fiber optic chemical dosimeter system detects the presence of hydrazine fuels and nitrogen tetroxide and nitrogen dioxide gases that are used at rocket launch sites using colorimetric sensors that react selectively with the gases and then absorb laser light communicating through a fiber optic network having a conventional diode laser source transmitting interrogation pulses to a plurality of distributed sensors covering a wide area launch site, the sensor being reactive cladding or distal end types both providing optical reflective returns well suited for reflective near infra-red and visible-red laser interrogation by an optical time domain reflectometry monitor which compares the interrogated laser pulses with sensor returns to determine the extent and location of gas cloud exposures over the distributed wide area.Type: GrantFiled: September 27, 1996Date of Patent: May 5, 1998Assignee: The Aerospace CorporationInventors: Bernardo Jaduszliwer, Charles M. Klimcak, Gary L. Loper
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Patent number: 5712166Abstract: A method and materials are described for the monitoring of ionizing radiation in a location or on a person. The method comprises providing a fluorescent organic sensor material in the location where monitoring is required, the fluorescent organic sensor material having a molecular structure comprising at least one pair of fluorophore units, the units being held together by a spacer unit such that they are capable of interacting to produce a distinct fluorescence spectrum different from those of the individual fluorophore units; exposing the sensor material to the radiation; and determining any change in the fluorescence spectrum of the sensor material after exposure.Type: GrantFiled: May 28, 1996Date of Patent: January 27, 1998Assignee: British Nuclear Fuels, PLCInventor: Christopher J. Broan
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Patent number: 5674751Abstract: A fiber optic chemical dosimeter system detects the presence of hydrazine fuels and nitrogen tetroxide and nitrogen dioxide gases that are used at rocket launch sites using colorimetric sensors that react selectively with the gases and then absorb laser light communicating through a fiber optic network having a conventional diode laser source transmitting interrogation pulses to a plurality of distributed sensors covering a wide area launch site, the sensor being reactive cladding or distal end types both providing optical reflective returns well suited for reflective near infra-red and visible-red laser interrogation by an optical time domain reflectometry monitor which compares the interrogated laser pulses with sensor returns to determine the extent and location of gas cloud exposures over the distributed wide area.Type: GrantFiled: May 10, 1996Date of Patent: October 7, 1997Assignee: The Aerospace CorporationInventors: Bernardo Jaduszliwer, Charles M. Klimcak
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Patent number: 5674752Abstract: A fabric chemical sensor, a process and an apparatus is disclosed. The sensor, process and apparatus are for the detection, classification, identification and/or quantitation of one or more component chemicals of a chemical vapor via a resistance measurment made across sensor in response to exposure of the sensor to the chemical vapor.Type: GrantFiled: October 16, 1995Date of Patent: October 7, 1997Assignee: The United States of America as represented by the Secretary of the NavyInventors: Leonard J. Buckley, Greg Collins
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Patent number: 5610027Abstract: A method of determining cell membrane strength is disclosed, using focused light of selected frequency and energy density. The method is also useful in diagnosing the presence of certain diseases in cells, by comparing the membrane strength of cells exposed to cell-characteristic altering drugs to the membrane strength of a control group of cells.Type: GrantFiled: October 30, 1992Date of Patent: March 11, 1997Assignee: Micro-Med, Inc.Inventor: Frederick N. Miller
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Patent number: 5567622Abstract: A fiber optic chemical dosimeter system detects the presence of hydrazine fuels and nitrogen tetroxide and nitrogen dioxide gases that are used at rocket launch sites using colorimetric sensors that react selectively with the gases and then absorb laser light communicating through a fiber optic network having a conventional diode laser source transmitting interrogation pulses to a plurality of distributed sensors covering a wide area launch site, the sensor being reactive cladding or distal end types both providing optical reflective returns well suited for reflective near infra-red and visible-red laser interrogation by an optical time domain reflectometry monitor which compares the interrogated laser pulses with sensor returns to determine the extent and location of gas cloud exposures over the distributed wide area.Type: GrantFiled: July 5, 1995Date of Patent: October 22, 1996Assignee: The Aerospace CorporationInventors: Bernardo Jaduszliwer, Charles M. Klimcak
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Patent number: 5532139Abstract: A microphotolysis and microphotoanalysis process applying precise quantities of focused light energy to a precise microscopic area of a very small cell sample to activate a chemical agent which permits measurement of cell fragility.Type: GrantFiled: March 31, 1995Date of Patent: July 2, 1996Assignee: Micro-Med, Inc.Inventor: Frederick N. Miller
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Patent number: 5468645Abstract: A method for reading and analyzing a diffusion-cell colorimetric exposimeter for making a quantitative determination of the time-weighted average (TWA) exposure to airborne gases or vapors. The diffusion cell is optically scanned to form color video signal data representative of the primary color components of the image formed from the reaction of the chromophoric reagent and pollutant. The data is converted to digital data and processed to compute exposure for a given pollutant gas as a function of color intensity for at least one of the primary color components.Type: GrantFiled: July 26, 1993Date of Patent: November 21, 1995Inventors: Kirollos S. Kirollos, Gueorgui M. Mihaylov, Kevin L. Lockerby, Roman A. Stobnicki
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Patent number: 5358875Abstract: A sensing chemistry for halogenated hydrocarbons includes pyridine or a pyridine derivative and a strong organic alkoxide base. The sensing chemistry may be in a nonaqueous organic solvent or in a solid state matrix. The base reacts with the halohydrocarbon to produce a carbene intermediate reaction product, which in the absence of water preferentially reacts with the pyridine to form a colored and/or fluorescent product.Type: GrantFiled: June 25, 1993Date of Patent: October 25, 1994Assignee: FIC - FiberChem, Inc.Inventors: Kisholoy Goswami, Dileep K. Dandge, Stanley M. Klainer, Chuka H. Ejiofor
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Patent number: 5354689Abstract: The present invention provides for a method for detecting the presence of isocyanate in a sample by (a) contacting an isocyanate derivatizing reagent having the formula IR--R' (I)wherein R is 9-anthracenylmethyl or a derivative thereof and R' is a radical having a single isocyanate-derivatizing functionality comprising a radical derived from a cyclic secondary amine with a sample under conditions suitable to the formation of a reaction product capable of detection and (b) detecting the presence or absence of the reaction product as an indication of the presence or absence of isocyanate in said sample. The present invention also provides a method of quantifying the total isocyanate presence by quantifying the reaction product.Type: GrantFiled: May 10, 1993Date of Patent: October 11, 1994Assignee: The United States of America as represented by the Department of Health and Human ServicesInventor: Robert P. Streicher
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Patent number: 5223439Abstract: The invention provides a radon daughter dosemeter made up of a cyclone, a filter in a filter holder and a radiation detector spaced from the filter. The filter is arranged to filter dust and aerosol particles from air issuing from the air outlet of the cyclone, and the detector is arranged to detect radiation from dust and aerosol particles on the filter. The invention also provides a method of monitoring radiation exposure of persons; and an electrochemical etching cell for the etching of detectors used in the dosemeter.Type: GrantFiled: October 26, 1992Date of Patent: June 29, 1993Assignee: Atomic Energy Corporation of South Africa LimitedInventor: Rainer Rolle
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Patent number: 5185129Abstract: An ozone monitor including an ozone reactive surface, held within a container, which is adapted to specifically react with ozone. The surface is also adapted to fail to react with nitrogen dioxide in an amount which affects ozone quantitation by more than 20% when the nitrogen dioxide is provided at a concentration of 76 ppb and ozone is provided at a concentration of 30 ppb within a test gas.Type: GrantFiled: February 28, 1991Date of Patent: February 9, 1993Assignee: President and Fellows of Harvard CollegeInventors: Petros Koutrakis, Jack M. Wolfson
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Patent number: 5145645Abstract: A selective chemical species detector including a conductive polymer based sensing element having a detectable characteristic, for example, the polymer resistivity, permanently altered on exposure to a first chemical species and not permanently altered on exposure to a second chemical species. The detector then determines a permanent change in the detected characteristic and indicates the presence of a chemical species on detection of a such a permanent characteristic change. Also disclosed is a method of fabricating such a sensing element to achieve the desired selectivity.Type: GrantFiled: June 3, 1991Date of Patent: September 8, 1992Assignee: Spectral Sciences, Inc.Inventors: Mitchell R. Zakin, Lawrence S. Bernstein, Richard A. Moody
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Patent number: 5128268Abstract: An apparatus for detecting or measuring the concentration of an analyte gas in a gas sample, which apparatus comprises a donor polymer and a halogen-containing compound positioned to contact the analyte gas and capable of reacting with the analyte gas to yield halogen; and a method for using the apparatus.Type: GrantFiled: June 20, 1989Date of Patent: July 7, 1992Assignee: President and Fellows of Harvard CollegeInventors: Masakazu Hishinuma, Yukio Yanagisawa
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Patent number: 5116577Abstract: The invention is directed to a dosimeter for detecting gaseous or aerosol substances. The dosimeter contains a collecting reagent in a tubular shell made of a membrane permeable for the substance to be detected. The dosimeter is improved so that also substances which cannot be absorbed by the collecting reagent can be made detectable. The dosimeter includes an outer shell wherein at least one additional inner shell is provided extending coaxially to the outer shell. The two shells conjointly define an intermediate space wherein a conversion reagent is accommodated for converting the substance to be detected into a conversion product. The inner shell defines an inner space wherein the collecting reagent is disposed for collecting the conversion product.Type: GrantFiled: March 8, 1990Date of Patent: May 26, 1992Assignee: Dragerwerk AktiengesellschaftInventors: Edgar Eickeler, Ralf Loffelholz
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Patent number: 5112768Abstract: A method and device involving use of the reaction product of an aldehyde acidified with sulfuric acid in acetone for sensing moisture. The reaction product is used as a coating for colorimetric detection of humidity, the color of the coating changing as a function of the humidity level. The coating is applied to a thin layer chromatography plate which is received in a badge housing to provide a real-time colorimetric dosimeter for monitoring humidity and indicating its presence.Type: GrantFiled: June 18, 1990Date of Patent: May 12, 1992Inventor: Patricia T. Carver
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Patent number: 5110551Abstract: A personal dosimeter for measuring the average concentration of undesirable contaminants gases such as nitrogen oxide includes a gas permeable web-like wafer formed of a material inert to polyamine. The wafer has a surface area having a numerical value at least one thousand times the value of the axial width of the wafer. The wafer is soaked in an absorptive medium not containing the ambient contaminant gas to be measured. The wafer, so soaked, is inserted within a gaseous impermeable housing from which the wafer may be selectively release and re-inserted. During an interval of release of the wafer, it is exposed for a predetermined interval of time to the ambient atmosphere. After re-insertion, the dosimeter is taken to an analysis site at which the wafer is removed and the molar concentration of products reaction with the atmospheric contaminant is measured.Type: GrantFiled: January 3, 1991Date of Patent: May 5, 1992Assignee: ORE Research InstituteInventor: Jan Michal
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Patent number: 5106759Abstract: A method for collecting radon in a confined area and testing therefor includes the initial step of providing a container with a molecular sieve material for attracting radon and placing the container in a confined area where radon is suspected to be present. The container has an open inlet end, into which radon will be attracted by the molecular sieve material in the container. The container is left in the confined area for a predetermined time, after which the container is removed so as to remove any radon present within the confined area and the molecular sieve is tested for radon.Type: GrantFiled: December 13, 1989Date of Patent: April 21, 1992Inventor: Clark D. Addison
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Patent number: 5069879Abstract: The invention is directed to an arrangement for detecting gaseous components in air wherein an air pumping device pumps a sample quantity through the testing tube. The air pumping device includes a receiver for the testing tube and the charge in the testing tube is evaluated. The arrangement is improved in that the detection of different components with the corresponding testing tubes is conducted automatically in that the data characteristic for the measurement is automatically considered and processed to a display of the measured values. For this purpose, the testing tube is provided at its outer periphery with a machine-readable memory whose data is detected by a read unit when the testing tube is introduced into the receiver of the pumping device. The data from the machine-readable memory is conducted to an evaluation unit.Type: GrantFiled: June 16, 1989Date of Patent: December 3, 1991Assignee: Dragerwerk AktiengesellschaftInventors: Kurt Leichnitz, Wolfgang May, Wolfgang Bather, Wolfgang Evers
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Patent number: 5023055Abstract: The invention is directed to a flow tester for air wherein at least two different materials are accommodated in at least two supply chambers. A visible aerosol is formed when the materials are mixed. The flow tester is improved with respect to an optimal adjustment of the mixing ratio of the components as well as providing a reduction of the flow resistance. The flow tester includes at least two supply chambers which are connected in parallel with respect to the flow therethrough.Type: GrantFiled: October 21, 1988Date of Patent: June 11, 1991Assignee: Dragerwerk AktiengesellschaftInventor: Johannes Heckmann
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Patent number: 5013668Abstract: A method of estimating a cumulative exposure to a component of a gas which comprises contacting a liquid reagent held by surface tension in a reservoir with a body of the gas through a conduit into which substantially only diffusional migration of the component from the body of gas occurs.Type: GrantFiled: February 10, 1989Date of Patent: May 7, 1991Assignee: Imperial Chemical Industries PLCInventor: Bernard Fields
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Patent number: 4963324Abstract: The invention relates to a colorimetric dosimeter including an indicator housing openable at one end and having a wall defining an interior space extending along the length thereof. The housing is partitioned into a first portion starting at the one end and a second portion following behind the first portion. A strip indicator defines a high-sensitivity region and is disposed in the first portion so as to conjointly define a clear through diffusion passage with the wall which extends to the second portion. A granular indicator defining a low-sensitivity region is disposed in the second portion.Type: GrantFiled: September 1, 1988Date of Patent: October 16, 1990Assignee: Dragerwerk AktiengesellschaftInventor: Wolfgang May
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Patent number: 4946649Abstract: A colorimetric gas diffusion testing tube is disclosed that is to be opened at one end and that contains a granular indicator layer. The testing tube detects a gas that does not directly change the color of the indicator layer. When the tube is viewed from the end which is to be opened, the indicator layer that is adjacent the opening end is inert to the gas that is to be detected. The indicator layer is followed by a porous reagent layer for converting this gas into the substances that change the color of the indicator layer.Type: GrantFiled: January 30, 1986Date of Patent: August 7, 1990Assignee: Dragerwerk AktiengesellschaftInventor: Karl-Heinz Pannwitz
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Patent number: 4933144Abstract: The invention is directed to a gas measuring device having a pretreatment device for converting the gas to be detected into a substance indicatable via a colorimetric indicator. The gas measuring device simplifies the detection of fluorine and includes a pretreatment device which has a chloride compound containing a metal of the first or second main groups of the periodic system and is exposed to the fluorine and has a chlorine indicator.Type: GrantFiled: March 11, 1988Date of Patent: June 12, 1990Assignee: Dragerwerk AktiengesellschaftInventor: Wolfgang May
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Patent number: 4913881Abstract: The invention relates to a dosimeter wherein the substances to be detected color a chemical sensor layer. The degree of coloration of the chemical sensor layer is measured by a photometric diffusion-reflectance measuring device. This dosimeter is improved with respect to a measurement occurring during the time that the contaminant substance is effective. The foregoing is accomplished with the dosimeter of the invention in that the dosimeter has a measuring chamber which receives a diffusion element and with a light impermeable wall portion which closes off the diffusion element while at the same time being permeable to the substance to be detected. A light source and a photosensor are arranged in the measuring chamber.Type: GrantFiled: October 13, 1988Date of Patent: April 3, 1990Assignee: Dragerwerk AktiengesellschaftInventor: Wolfgang Evers
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Patent number: 4913882Abstract: A diffusion sampler includes a vessel which has at least one inlet opening exposed to the gas to be investigated and which has a moderating zone. In its interior, the vessel has a collecting region provided with a collecting medium as well as a conversion region for converting the gas into substances which can be taken up by the collecting medium. The diffusion sample is improved in that its detection sensitivity is increased and that the collecting region as well as the converting region are provided with large areas in a manner adapted to the geometry of the vessel so that a smaller and more manipulable configuration is obtained. In addition, long-term dosimetry is made possible. For this purpose, the moderating zone is configured as a permeable barrier from which the converting region as well as the collecting region extend and determine the diffusion path in the entire interior of the vessel with each region being applied to a carrier.Type: GrantFiled: September 1, 1988Date of Patent: April 3, 1990Assignee: Dragerwerk AktiengesellschaftInventors: Wolfgang May, Edgar Eickeler, Wolfgang Evers
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Patent number: 4904449Abstract: The invention is directed to a colorimetric gas measuring device with an indicator path which is accessible for the gas to be detected via at least one inlet opening and which, however, is otherwise closed off with respect to the ambient. The colorimetric gas measuring device is improved so that the measuring time is extended and the sensitivity increased while at the same time providing a space-saving configuration. The gas measuring device is small and convenient to handle and can be carried on the person. For this purpose, the indicator paths are configured so as to extend in circuitous manner.Type: GrantFiled: March 11, 1988Date of Patent: February 27, 1990Assignee: Dragerwerk AktiengesellschaftInventor: Johannes Heckmann
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Patent number: 4900681Abstract: A solution of various benzaldehyde derivatives dissolved in suitable solvents are used in impinger sampling or as a coating on substrates to provide passive, real-time visual colorimetric indication of the presence of hydrazine and its derivatives.Type: GrantFiled: June 2, 1988Date of Patent: February 13, 1990Inventors: Patricia A. Taffe, Susan L. Rose-Pehrsson
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Patent number: 4900936Abstract: A dosimeter for detection of noxious substances which are collected on a plaque-like substrate carrier, which is closed off against the outside by a diffusion membrane fitted to it, is improved so that a uniform fit can be achieved over the entire surface of the membrane. For this, the substrate carrier is curved outwardly.Type: GrantFiled: June 10, 1988Date of Patent: February 13, 1990Assignee: Dragerwerk AktiengesellschaftInventor: Wolfgang Evers
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Patent number: 4844867Abstract: A colorimetric detector such as a gas dosimeter, contains a strip-like carrier with a detection reagent in a transparent housing that can be opened at least at one end thereof. The detector is expanded in terms of its use to such reagent systems in which the pigment formed diffuses beyond the reaction zone. For this purpose, the detection reagent is provided such that it is contained in impregnated tabs arranged in a row on the carrier.Type: GrantFiled: May 20, 1987Date of Patent: July 4, 1989Assignee: Dragerwerk AktiengesellschaftInventor: Wolfgang Bather
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Patent number: 4795611Abstract: An indicator for the documentation of chlorine by discoloration of potassium iodide applied on a support is to be improved so that it is sufficiently sensitive for the documentation of the low chlorine concentrations and also has, for the documentation of high concentrations, a stable dicoloration. To this end it is provided that the indicator comprises an addition of manganese chloride.Type: GrantFiled: April 21, 1987Date of Patent: January 3, 1989Assignee: Dragerwerk AGInventor: Carl-Ernst van der Smissen
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Patent number: 4790857Abstract: A gaseous contaminant dosimeter apparatus for collecting, for subsequent analysis, a gaseous contaminant in proportion to its average concentration in the ambient atmosphere over a predetermined collection period. The gaseous contaminant dosimeter apparatus includes a closed chamber containing a medium capable of chemically or physically combining with the selected gaseous contaminant, and porous diffusive material formed from a material through which the contaminant may diffuse at a rate that is proportional to its atmospheric concentration and substantially unaffected by convective movements of the ambient atmosphere, is mounted in fluid impeding relation with the chamber. The diffusive material includes at least two layers of microporous membrane material having a multiplicity of pores which individually have effective cross-sectional dimensions that are smaller than the mean free path length of the contaminant, the membrane material being mounted on the opposite sides of a porous support substrate.Type: GrantFiled: November 20, 1986Date of Patent: December 13, 1988Inventor: Robert R. Miksch
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Patent number: 4791155Abstract: An assembly for monitoring ionising radiation which comprises coated on a base a binder layer containing a polychlorinated hydrocarbon and a color former.The assembly can be used to monitor levels of radiation of from 0.1 MRads to 10.0 MRads.Type: GrantFiled: July 22, 1987Date of Patent: December 13, 1988Assignee: Ciba-Geigy AGInventors: David P. Gregory, Bernard J. Dean, Stephen R. Postle
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Patent number: 4783316Abstract: A colorimetric gas dosimeter, which contains a granular indicator substance in a closed, transparent, hollow unit that can be opened on one side, is provided in such a way that the diffusion cross section for the hazardous substance molecules is independent of the degree of discoloration of the indicator substance and the detection sensitivity is thereby increased. This is achieved by sub-dividing the hollow unit into several chambers extending along its longitudinal axis, at least one of which is filled with the granular indicator, and is located adjacent to an indicator free chamber and is separated from this by a separating wall permeable to gas.Type: GrantFiled: September 30, 1986Date of Patent: November 8, 1988Assignee: Dragerwerk AGInventor: Karl-Heinz Pannwitz
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Patent number: 4780282Abstract: A dosimeter for collecting vapors and gases of hydrazine and of hazardous derivatives of hydrazine such as monomethylhydrazine and 1,1-dimethylhydrazine, employs a housing with a perforated cover. Situated inside the housing is a removable disk on which is coated a solution of citric acid in methanol. The solution initially contains 20% to 30% of citric acid monohydrate dissolved in methanol and the solution is permitted to age for seven or eight days before being coated on to the disk.Type: GrantFiled: September 9, 1986Date of Patent: October 25, 1988Assignees: Geo-Centers, Inc., United States of AmericaInventors: James R. Holtzclaw, Susan L. Rose, Jeffrey R. Wyatt, Chester M. Hawkins
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Patent number: 4748930Abstract: A device for indicating the presence of a gas includes a closed housing having an interior wall with a color indicator disk on one side wall and an opposite wall having an opening with an inflow pipe for the inflow of the gas to be detected. The interior of the housing forms a flat measuring chamber having the side wall with the detector disk of a size comparable to the length and diameter of the inflow pipe so as to form a diffusion area across which a mass transport of the gas to be detected takes place, that is, largely independent of air currents. The color indicated disk advantageously has a circular periphery and the inflow pipe is of cylindrical section and it is smaller than one-fifth the diameter of the measuring chamber having the disk. Advantageously, the length of the pipe section is less than the thickness of the measuring chamber.Type: GrantFiled: February 19, 1987Date of Patent: June 7, 1988Assignee: Dragerwerk AktiengesellschaftInventor: Kurt Leichnitz
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Patent number: 4731333Abstract: A solid detecting reagent for gaseous hydrides and a gaseous hydride detecting method are disclosed, said reagent comprising a basic copper carbonate as a color changing component and undergoing color change upon contact with at least one gaseous hydride selected from the group consisting of arsine, phosphine, diborane, hydrogen selenide, germane, monosilane, disilane and dichlorosilane. The reagent is applicable to all of these gaseous hydrides and, upon contact therewith, rapidly changes from an initial blue color to a black color, said black color standing for a long period of time.Type: GrantFiled: June 25, 1986Date of Patent: March 15, 1988Assignee: Japan Pionics., Ltd.Inventors: Koichi Kitahara, Takashi Shimada
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Patent number: 4680165Abstract: A dosimeter is provided for collecting and detecting vapors and aerosols of organic compounds. The dosimeter comprises a lightweight, passive device that can be conveniently worn by a person as a badge or placed at a stationary location. The dosimeter includes a sample collector comprising a porous web treated with a chemical for inducing molecular displacement and enhancing phosphorescence. Compounds are collected onto the web by molecular diffusion. The web also serves as the sample medium for detecting the compounds by a room temperature phosphorescence technique.Type: GrantFiled: March 19, 1982Date of Patent: July 14, 1987Inventor: Tuan Vo-Dinh
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Patent number: 4666859Abstract: A novel colorimetric reagent for the selective determination of formaldehyde in solution or in air is described. The reagent comprises at least two chemicals: rubeanic acid or a rubeanic acid derivative, and a cyano complex of a metal. Upon addition of formaldehyde, a color is formed which is quantitatively related to the number of formaldehyde molecules reacted. The chromophoric reagent can be mixed with other inactive ingredients such as stabilizers, buffers, polymers, etc. and used in solutions as a coating on a flat surface, or on beads to detect and determine formaldehyde colorimetrically. One particular application of the colorimetric reagent is in a direct reading colorimetric gas dosimeter for formaldehyde.Type: GrantFiled: May 19, 1986Date of Patent: May 19, 1987Assignee: Perfect View IncorporatedInventor: Amir J. Attar
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Patent number: 4482635Abstract: There are disclosed an improved CO indicating composition consisting essentially of fumed silica having dispersed thereon dry residues of impregnation with a solution of palladium sulfate, sulfuric acid and ammonium molybdate, a CO indicator comprising a strip of a composite of expanded, amorphous-locked tetrafluoroethylene polymer and fumed silica having dried residues of impregnation with the aforesaid solution, an improved detector containing said indicating composition or said indicator, and improved process for detecting CO comprising exposing pre-dried air to the indicating composition or said indicator to effect a color change, extracting colored material with distilled water or an aqueous buffer solution, and measuring the depth of color in the resulting extract.Type: GrantFiled: September 22, 1983Date of Patent: November 13, 1984Assignee: E. I. Du Pont de Nemours & CompanyInventors: Thomas Herskovitz, William G. Peet
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Patent number: 4478792Abstract: A gas dosimeter comprises a stack of porous sheets, impregnated with a reagent that changes color on contact with the gas to be determined, contained in a housing which has an opening to expose one end of the stack to the atmosphere to be tested. The gas to be determined penetrates by diffusion the layers of porous sheets, causing the sheets in the stack to change color sequentially from the end of the stack exposed to the atmosphere. The degree of penetration through the layers of porous sheets is a function of dosage exposure. The housing may be transparent with each superposed sheet in the stack being larger than the adjacent underlying sheet, so that each sheet is visible through the housing endwall.Type: GrantFiled: September 16, 1983Date of Patent: October 23, 1984Assignee: Mine Safety Appliances CompanyInventors: Paul W. McConnaughey, Elmer S. McKee
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Patent number: 4436819Abstract: A device for chemically quantifying ethylene oxide exposure is disclosed as are methods for its use. The device comprises an ethylene oxide-permeable layer exhibiting unusual non-Fickian EO transport and containing a controlled amount of compound which forms a colored species upon reaction with ethylene oxide. Optionally, the response layer is laminated or otherwise joined with a support layer. The device can be used to quantify in industry accepted units of time and concentration sterilization dosages of ethylene oxide.Type: GrantFiled: March 3, 1982Date of Patent: March 13, 1984Assignee: Assay Tec Associates, Inc.Inventor: Charles R. Manning
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Patent number: 4380587Abstract: Method for the determination of fluidic-contained aldehydes. The method comprises bringing into contact said aldehyde and a chemically inert substrate having adhered to the surface thereof a substantially monodisperse system of particles of a derivatizing agent for the aldehydes thereby forming nucleating crystals; treating said nucleating crystals with a metastable supersaturated solution in which said nucleating crystals can grow; growing said nucleating crystals to form an optically measurable film of crystals; and optically measuring said film of crystals to determine the concentration of fluidic-contained aldehydes.Type: GrantFiled: August 20, 1981Date of Patent: April 19, 1983Assignee: Arthur D. Little, Inc.Inventor: Martin Koocher