Abstract: A semiconductor gas sensor device includes a first cavity that is enclosed by opposing first and second semiconductor substrate slices. At least one conducting filament is provided to extend over the first cavity, and a passageway is provided to permit gas to enter the first cavity. The sensor device may further including a second cavity that is hermetically enclosed by the opposing first and second semiconductor substrate slices. At least one another conducting filament is provided to extend over the second cavity.

Abstract: A gas monitoring apparatus and system that provides for reliable and accurate monitoring of gaseous hydrogen and other compounds in dielectric oil. The apparatus provides an environment for and is used in conjunction with metal oxide semiconductor sensors. Thermal conditioning zones for oil provide an environment in which variations in oil temperature and ambient temperature are eliminated to insure that analytical data are not affected by these environmental conditions.

Abstract: A structure for operating a system for utilizing exhaust heat of a vehicle may include a high-temperature part with an exhaust pipe and a bypass passage installed in the exhaust pipe, a thermoelectric element attached to an exterior of the exhaust pipe for generating electricity, a low-temperature part attached to an exterior of the thermoelectric element for flowing a coolant, a first exhaust gas passage installed in the low-temperature part and having both ends connected to the exhaust pipe, a first valve to selectively open or close the first exhaust gas passage, a second exhaust gas passage formed in a space between the inner circumferential surface of the exhaust pipe and an outer circumferential surface of the bypass passage, a second valve disposed at a rear end of the bypass passage, coupled to a valve shaft and rotatable on the basis of the valve shaft, and an operating unit.

Abstract: Provided is a gas sensor that needs no temperature sensor for detecting a temperature of a heater for preventing dew condensation. The gas sensor comprises a hydrogen sensor 1 including: an element housing 13 having a detection chamber 13a to which hydrogen is introduced; a detection element 31 arranged in the detection chamber 13a and detecting hydrogen; a heater 21 for heating the detection chamber 13a by heat generation via passing an electric current through the heater 21, a resistance value of the heater 21 being changed corresponding to a temperature of the detection chamber 13a; and a microcomputer 51 and a heater operation circuit 52 for controlling the heater 21. Herein, the microcomputer 51 controls a temperature of the detection chamber 13a by adjusting the electric current passing through the heater 21 based on the resistance value of the heater 21.

Abstract: A gas-sensing element configured to measure a concentration of a specific component of a gas is mounted to a first circuit board which includes a driving circuit configured to drive the gas-sensing element. A moisture-proof material is disposed over at least one side of the first circuit board disposed in a tubular gas-sensing element case fixed to a sensor case. A gas-sensing chamber is defined by the first circuit board and an inner tubular surface of the gas-sensing element case, and opens at an open end of the gas-sensing element case to receive the gas to be monitored. A second circuit board which includes a control circuit configured to control the gas-sensing element via the driving circuit is fixed to a sensor case, and disposed in a position separate from the gas-sensing chamber such that the second circuit board is kept out of contact with the gas to be monitored.

Abstract: Methane gas in a ruminant exhalation may be oxidized to reduce the amount of methane gas output by the ruminant.

Abstract: A gas sensor is provided. The substrate of the gas sensor has a first surface, a second surface and a cavity. The cavity has an opening at the first surface. An insulating film is disposed on the first surface and covers the opening. A heating unit is embedded in the insulating film and located above the opening. An electrode pair is disposed on the insulating film and electrically separated from the heating unit. A buffer layer is disposed on the insulating film and located above the heating unit. The buffer layer is electrically connected to the electrode pair, and at least part of an orthogonal projection of the buffer layer on the first surface is located on the substrate next to the opening. The gas sensing layer is disposed on the buffer layer and has a nano-catalyst therein.

Abstract: A gas sensor includes a substrate having a low thermal conductivity. Localized heating can be produced using a serpentined heater carried by the substrate. The low thermal conductivity of the substrate substantially confines the generated heat to a region local to the heater thereby reducing required power to operate the sensor. Multiple sensing elements can be deposited onto the substrate adjacent to respective heaters and relatively close together because of the thermal isolation provided by the substrate. In one embodiment, the sensor can include the ceramic substrate, the heater, catalytic material overlying the heater with a gas impermeable layer overlying, at least in part the catalytic material.

Abstract: An oxygen sensor comprising an oxygen sensing compound and configured to substantially mitigate leaching of the oxygen sensing compound from the oxygen sensor to an outer surface thereof is provided. The oxygen sensor may comprise one or more layers. A first portion of the oxygen sensor is configured to be permeable to gas and comprises an oxygen sensing material. A second portion is disposed with or on the first portion and is configured to be permeable to gas and substantially impermeable to the oxygen sensing material.

Abstract: A device for sensing a gas comprises a plastics housing (106, 107) moulded in situ around at least one portion of a conducting lead frame (100), the housing defining an enclosure (113) and being provided with means for enabling gas flow into the enclosure. A gas sensitive element (114) within the enclosure (113) is mounted to the conducting lead frame (100). The conducting lead frame (100) comprises connection leads which are accessible through, and at least partially encapsulated by, the wall of the housing.

Abstract: A microfabricated TID comprises a microhotplate and a thermionic source disposed on the microhotplate. The microfabricated TID can provide high sensitivity and selectivity to nitrogen- and phosphorous-containing compounds and other compounds containing electronegative function groups. The microfabricated TID can be microfabricated with semiconductor-based materials. The microfabricated TID can be combined with a microfabricated separation column and used in microanalytical system for the rapid on-site detection of pesticides, chemical warfare agents, explosives, pharmaceuticals, and other organic compounds that contain nitrogen or phosphorus.

Abstract: A gas detection apparatus A comprises a signal processing circuit 20, a Wheatstone bridge circuit 21, integrating circuits 22 and 23, a differential amplification circuit 24, a direct current power supply circuit 25, a heater voltage application circuit 26. The Wheatstone bridge circuit 21 is configured of parallel combination of series circuits: one composed of a catalytic combustion type gas sensor 1 and a load resistor R1, and the other composed of a resistor R2, a variable resistor VR1 and a resistor R3. The heater voltage application circuit 26 is configured to generate a pulsed heater voltage by switching a direct current voltage of the direct current power supply circuit 25 through a transistor TR1 for applying the pulsed heater voltage to the Wheatstone bridge circuit 21. The integrating circuit 22 integrates a voltage at a connection point between the gas sensor 1 and the load resistor R1.

Abstract: A circuit with at least one catalytic measuring element (1), in which the at least one catalytic measuring element (1) is connected to a supply voltage (5) without a protective resistor and without a thermal safety device arranged upstream. The circuit makes it possible to develop gas-measuring devices with catalytic measuring elements that are characterized by an especially low power consumption.

Abstract: A gas sensor which includes walls delimiting a gas detection chamber, and having an introduction port (or an inlet) through which an observed gas is introduced into the gas detection chamber, a measuring element disposed in the gas detection chamber and measuring concentration of a subject gas contained in the observed gas, and a heater constituting at least a portion of the walls, the portion facing the gas detection chamber.

Abstract: A gas sensor includes a substrate having a low thermal conductivity. Localized heating can be produced using a serpentined heater carried by the substrate. The low thermal conductivity of the substrate substantially confines the generated heat to a region local to the heater thereby reducing required power to operate the sensor. Multiple sensing elements can be deposited onto the substrate adjacent to respective heaters and relatively close together because of the thermal isolation provided by the substrate. In one embodiment, the sensor can include the ceramic substrate, the heater, catalytic material overlying the heater with a gas impermeable layer overlying, at least in part the catalytic material.

Abstract: A gas sensor including: a gas detection element; a metal shell extending in an axial direction; and a metal cylinder extending in an axial direction, wherein a leading end portion of the metal cylinder surrounds a base end portion of the metal shell and is fixed to the metal shell via a circumferential welded portion. The metal shell includes: Fe in an amount equal to or more than 50.0 mass %; C in an amount of 0.02 mass % to 0.15 mass %; Cr in an amount of 11.5 mass % to 18.0 mass %; and Nb in an amount equal to or more than twice amount of C in mass %.

Abstract: A low power consumption catalytic gas sensor includes three beads. A trigger bead, which is smaller than either a sensing on a compensating bead can be monitored for the presence of a combustible gas. Where gas has been sensed, the sensing and compensating beads can be energized to establish a gas concentration.

Abstract: Detecting air ingredients is obtained, a heater and gas sensitive acting layers are arranged on a substrate, which are connectable to an analyzing unit. Electrical resistances of n acting layers are connected in series; heater is a temperature sensor connected in parallel with this series connection, electrical resistance of heater is smaller than the sum of electrical resistances of acting layers and resistances are connected with a total of n+1 electrical terminals via electrodes so that heater is connected with two terminals and n?1 other terminals are connected with a respective junction that interconnects two acting layers. Heater is intermittently heated so that a predefined constant temperature of acting layers is achieved, temperature of acting layers is acquired by determining electrical resistance of heater; voltages in the series connection of acting layers are analyzed and a concentration of gases are determined from electrical resistances of acting layers.

Abstract: A vapor analysis system comprising a vapor analyzer capable of collecting and analyzing a vapor sample for detection of a compound that may be contained within the vapor sample. A controller is coupled to the vapor analyzer. The controller is programmed to produce an indicator signal indicative of a relative concentration of the compound detected by the vapor analyzer within the vapor sample. A sample probe includes a housing containing a vapor channel through which the vapor sample is collected, and a vapor cable couples the sample probe to the vapor analyzer to allow collection and channeling of the vapor sample to the vapor analyzer. A multi-dimensional user indicator is disposed on the housing of the sample probe receives and operates in response to the indicator signal to indicate the relative concentration of the compound detected within the vapor sample for presentation via a multi-directional stimulus to a user of the vapor analysis system.

Abstract: A microelectro-mechanical chemical sensor includes an active cantilever beam having a chemically selective material layer disposed thereon and at least one, preferably two, resistors with the resistance corresponding to the cantilever beam deflection. The sensor also has at least two, and preferably four, auxiliary cantilever beams adjacent to the active cantilever and attached to the same substrate, each having a piezoresistor disposed thereon. The piezoresistors are elements of a Wheatstone bridge, and the Wheatstone bridge output indicates the amount of a predetermined target chemical sorbed by the chemically selective material layer. The sensor is electrostatically actuated in order to monitor the resonant frequency.

Abstract: An installation structure for a gas sensor capable of detecting gas concentration in a highly accurate manner is provided. The installation structure for a gas sensor which detects concentration of gas circulating inside an outlet-side piping comprises a through hole 18 in an inner wall of the outlet-side piping and the gas sensor comprises a gas inlet portion with one face open within the outlet-side piping 14, and the gas sensor is installed to the outlet-side piping in a condition where the gas inlet portion does not protrude from the inner wall of outlet-side piping.

Abstract: A contact combustion-type gas sensor that can maintain its initial sensitivity over a long period of time in the presence of silicon vapor, wherein an induction portion 5 of a gas detecting element 1 contains not less than 30 percent by weight of an oxidation catalyst, and is aged in advance in an environment that contains silicon vapor serving as a poisoning substance.

Abstract: A hydrogen sensor 25 has a fitting base plate 29 in which a gas-sensing chamber 34 is formed, a specimen gas intake 35 formed on said fitting base plate 29, opening toward an exit passage 24 and introducing hydrogen gas into the gas-sensing chamber 34, a gas-sensing element 39 held in the gas-sensing chamber 34 and adapted to sense hydrogen gas, and a water-repelling filter 44 covering the specimen gas intake 35.

Abstract: In order to provide a step capable of reliably detecting a CO concentration in a reformed gas at low cost and a hydrogen purifier capable of fully exerting a function of a CO purifying catalyst, a gas concentration detector comprising a reaction chamber which has a catalyst layer and a gas temperature detector and capable of detecting the concentration of carbon monoxide in the gas by means of a signal of the temperature detector referring to a reformed gas passing along through the reaction chamber.

Abstract: New sensors and methods for qualitative and quantitative analysis of multiple gaseous substances simultaneously with both high selectivity and high sensitivity are provided. The new sensors rely on a characteristic difference in energy between the interaction of a particular substance with a catalyst coated heat transfer device (HTD) and a non-catalyst coated (or one coated with a different catalyst) reference HTD. Molecular detection is achieved by an exothermic or endothermic chemical or physical reaction between the catalytic surface of the sensor and the molecule, tending to induce a temperature change of the sensor. Both high temperature and non-destructive low temperature detection are possible. The magnitude and rate of endothermic or exothermic heat transfer from a specific molecule-catalyst interaction is related to molecular concentration.

Abstract: A method of determining bias in a measurement of a constituent concentration level in a sample gas is provided. The method comprises establishing a sample gas flow from an emission stream into a sample gas line of an emissions monitoring system. The method further comprises removing water from the sample gas flow and cooling the sample gas flow to a temperature below about 41° F. to produce a cooled, dried sample gas flow. The constituent concentration level is then determined for the cooled, dried sample gas flow. The method further comprises introducing a span gas having a known span gas constituent concentration level into the sample gas flow to form a combined sample and span gas flow, the span gas being introduced at a desired span gas flow rate. The method still further comprises removing water from the combined sample and span gas and cooling the combined sample and span gas to a temperature below about 41° F. to produce a cooled, dried, combined sample and span gas flow.

Abstract: A device and method for quantifying an impurity in an input gas stream. The device and method employ a catalyst to convert the impurity to a detectable species in an output gas stream, and the concentration of the detectable species is then measured by means of a detector.

Abstract: Provided is a gas molecule sensor, characterized in that the sensing element is a polycrystalline tin oxide film having a thickness less than 1 ?m. The sensing element is produced by electrolytic deposit of a tin film on an insulating support in an electromechanical cell, where the anode is comprised of tin and the cathode is a conductive film applied on the surface of the insulating support at one of its ends, the two electrodes being separated by an electrolyte comprised of a tin salt solution, and by passing a constant current through said cell. The deposit step is followed by an oxidizing step.

Abstract: A powder filler is stuffed in a filler space defined between a housing and a gas sensing element so as to airtightly seal a clearance between the housing and the gas sensing element. The powder filler contains grains whose diameter is in a range from 80 ?m to 5,000 ?m when measured before being stuffed into the filler space. A weight percentage of the grains having the diameter of 80 ?m to 5,000 ?m is equal to or larger than 80% with respect to an overall weight of the powder filler.

Abstract: Of a gas detector 100, a chamber 105 formed between a center cover 150 and a cover 160 is a part of an air flow channel AF. A first shielding plate 165 is provided in the chamber 105. Water droplets that have entered the chamber from a chamber entrance 103 with air hit and adhere to an entrance-opposed surface 165E of the first shielding plate 165. The water thus adhering to the surface is pushed by the air flowing along the entrance-opposed surface 165E and by gravity, to thereby advance downward. The water then drips downward and is accumulated on a bottom wall surface 105WD which serves as an upper surface of a bottom wall section 161WD. The water is pushed by the flow of air, to thereby advance toward a chamber exit 104. The water is then drained downward from the chamber exit 104.

Abstract: A lightweight and portable analyzer is provided. At least one component of the analyzer is made from a lightweight material, such as ABS. A manifold can have a plate and gas passages ultrasonically welded together. By having at least one component made from a lightweight material, the analyzer is lighter.

Abstract: A chemiresistor sensor probe for detecting target analytes. The probe includes a body having a first control surface and a second control surface recessed within the first. A sensor film comprises numerous conductive particles disposed upon the second surface. The film swells upon absorbing one or more analytes for which it has an affinity, thus causing the conductive particles to become more dispersed and increasing the resistance between the particles. The thickness of the film is equal to the distance between the first surface and the second surface, thus permitting the thickness to be controlled by varying the distance between the control surfaces. The robustness of the sensor probe is enhanced by placing a porous or mesh electrode along with, or in place of, a chemical binding agent between the film and the terminals. The robustness is also improved by placing a diode in series with the sensor circuit.

Abstract: A hydrocarbon sensor and collector. An element that is capable of absorbing and releasing hydrocarbons is positioned in the air intake system of a vehicle, upstream from the engine and wholly in the airflow. The element has a plurality of chambers defined in it that allow air to pass through the element. The hydrocarbon sensor and collector also includes a means for detecting the level of hydrocarbons absorbed by the element.

Abstract: A poison resistant combustible gas sensing element, a method for its production and a method for determining poisoning of the element. The element includes an electric heating element, an inner layer coated on the electric heating element and containing a precious metal catalyst supported on a porous oxide, the precious metal catalyst catalyzing combustion of a combustible gas to be detected by the element, and an outer layer overlaying the first layer, and containing a catalytic compound capable of trapping gases which poison the precious metal catalyst, the catalytic compound being supported on a porous oxide.

Abstract: A poison resistant combustible gas sensing element, a method for its production and a method for determining poisoning of the element. The element includes an electric heating element, an inner layer coated on the electric heating element and containing a precious metal catalyst supported on a porous oxide, the precious metal catalyst catalyzing combustion of a combustible gas to be detected by the element, and an outer layer overlaying the first layer, and containing a catalytic compound capable of trapping gases which poison the precious metal catalyst, the catalytic compound being supported on a porous oxide.

Abstract: Disclosed herein is a method and apparatus for analyzing, sensing and measuring the concentrations of various gases, including NOx, hydrocarbons, carbon monoxide and oxygen, in a multi-component gas system using chemical sensors and chemical sensor arrays. The sensors and sensor arrays use chemo/electro-active materials to analyze and detect the presence of gases.

Abstract: Intended for application on ducts through which flow a fluid at a high temperature, and particularly at a high pressure, comprising two bodies (4) and (8) which axially screw onto each other, one body (4) provided with a threaded neck (5) for attachment to the orifice of duct wall (3), which body (4) houses within it sensor element (2) of the probe which is thus placed inside the duct, with second body (8) screwed onto first body (4) and exerting on sensor element (2) the pressure required to secure it in its housing, with second body (8) further provided with an axial orifice through which passes a metallic tube (9) open to the exterior and which is provided with a metallic washer (10), soldered to said tube (9), which is separated from second body (8) by an electrically insulating washer (12).

Abstract: A combustible gas sensor includes an active element in electrical connection with a measurement circuit. The measurement circuit includes a thermistor network to compensate for the effect of changes in ambient temperature to the resistance of the active element. Another combustible gas sensor includes an active element having a geometric surface area no greater than approximately 0.5 mm2 in electrical connection with a measurement circuit. The measurement circuit includes a compensator that compensates for the effect of changes in ambient temperature to the resistance of the active element without compensating for heat lost by thermal conduction from the active element.

Abstract: A sensor for detecting a target matter includes a chemical sensitive layer that is operable to react when exposed to the target matter and a piezoresistive material coupled to the chemical sensitive layer. The chemical sensitive layer is configured such that the reaction of the target matter with the chemical sensitive layer creates an interfacial tension at the interface of the chemical sensitive layer and the piezoresistive material that changes the electrical resistance of the piezoresistive material. However, the chemical sensitive layer is configured such that the reaction of the target matter with the chemical sensitive layer does not affect the bulk properties of the chemical sensitive layer enough to change the electrical resistance of the piezoresistive material. The sensor also includes an electrical circuit coupled to the piezoresistive material that is operable to detect the change in the electrical resistance of the piezoresistive material due to the interfacial tension.

Abstract: Disclosed herein is a method and apparatus for analyzing, sensing and measuring information related to the concentrations of various gases, including NOx, hydrocarbons, carbon monoxide and oxygen, in a multi-component gas system using chemical sensors and chemical sensor arrays. The sensors and sensor arrays use chemo/electro-active materials to analyze and detect the presence of gases.

Abstract: An improved, affordable, and rapid fluid mixture composition or process monitor based on a thermal microstructure sensor. This is preferably accomplished with a microbridge sensor design that has reduced susceptibility to interfering components of the mixture. The sensor described herein is therefore suitable for monitoring the concentration of at least one component in a fluid mixture when the fluid mixture consists of either (1) two components with very different thermal conductivities; or (2) three or more components wherein at least one component has a very different thermal conductivity and the effects of the other components can be largely eliminated, especially if the component of interest is hydrogen and the interference is from the variability in the concentrations of CO2 and H2O.

Abstract: A single pass analyzer includes multiple infrared sensors, a catalytic converter, a scrubber and a thermal conductivity cell all coupled in series to provide a single pass (i.e., one sample) analyzer which allows for fast analysis, allows for the speciation of hydrogen samples, requires no purging between different sample types, utilizes a single carrier gas, and eliminates molecular sieves and Shutze converters. The resultant analyzer provides improved quicker results with less plumbing (i.e., gas conduits and valving) in a single instrument.

Abstract: A combustible gas sensor includes an active element in electrical connection with a measurement circuit. The measurement circuit includes a thermistor network to compensate for the effect of changes in ambient temperature to the resistance of the active element. Another combustible gas sensor includes an active element having a geometric surface area no greater than approximately 0.5 mm2 in electrical connection with a measurement circuit. The measurement circuit includes a compensator that compensates for the effect of changes in ambient temperature to the resistance of the active element without compensating for heat lost by thermal conduction from the active element.

Abstract: The present invention relates to a filtration-detection device for detecting or quantifying an analyte in a test sample including a filtration device having a first binding material immobilized thereto, wherein the first binding material is capable of binding to a portion of the analyte, and a detection assembly positioned relative to the filtration device to detect or quantify analyte bound to the first binding material. The present invention also relates to methods of using the filtration-detection device.

Abstract: A base is provided with a concave and three leads, and the central lead is bent to the side opposite to the concave, and the other leads are bent to the side of the concave. A central electrode of a sensor element is attached to the central lead and the bottom of the concave and a coil serving as both a heater and an electrode is attached to the other leads to support the sensor element on a small base at four points.

Abstract: A gas sensor for the detection of gases comprises a housing and an active element disposed within the housing. The active element is surrounded by a porous insulating material having a bulk density no greater than 0.15 g/cc. Another gas sensor comprises an active element surrounded by a porous insulating material having a surface area no greater than approximately 200 m2/cc. Another gas sensor comprises a copper compound positioned so that gas contacts the copper compound before contacting the active element. Another gas sensor comprises an active element surrounded by a porous material having an average pore size of at least approximately 100 Å. Another gas sensor comprises a heating element surrounded by a porous material that supports a catalyst.

Abstract: In this method of analyzing a gas mixture containing at least one inflammable gas to determine its explosibility, a resistive heating element (15) is energized in an analysis enclosure (12) communicating with the gas mixture to be analysed to burn the gas mixture in the enclosure, an electrical signal (S) at the terminals of the resistive element (15) is measured during combustion, and the explosibility of the gas mixture is determined from a comparison of values of the signal measured during a transient phase in which the concentration of the inflammable gas in the gas mixture is falling. The measurements taken during the transient phase are taken at times chosen to obtain, for different inflammable gases, substantially identical measurement signals for concentrations corresponding to identical explosibilities.

Abstract: An apparatus for identifying an unknown reactive gas in a carrier gas, utilizing a sensor with a diffusion limited inlet. The apparatus includes a manifold of predetermined volume having an inlet and outlet, an inlet valve in the manifold inlet, an outlet valve in the manifold outlet, a gas detector in communication with the manifold, a diffusion barrier disposed between the manifold and the gas detector for limiting diffusion of gas from the manifold into the gas detector, means for opening and closing the inlet and outlet valves, means for detecting an output signal from the gas detector, means for determining a coefficient of diffusion for the reactive gas from the output signal, and means for identifying and quantifying the reactive gas from the determined coefficient of diffusion.

Abstract: A method and apparatus for identifying an unknown reactive gas in a carrier gas, utilizing a sensor with a diffusion limited inlet. After a signal is established for the carrier gas, a flow of the mixture of carrier gas and reactive gas is passed to the sensor and a steady state signal S is established. Then, the input to and output from the sensor are closed, and the steady state signal decays as a known volume of reactive gas is consumed. The decay curve of the signal is integrated to produce an integrated response .SIGMA., and the ratio S/.SIGMA. is proportional to the diffusion coefficient for the reactive gas. By comparing this ratio to the ratio for a known reactive gas, the identity of the unknown reactive gas can be determined.

Abstract: A multilayered gas sensor for detecting the presence of gases in air. In particular, sensors are described for sensing hydrocarbons and nitrogen oxides. An additional feature of the invention is to provide a device that is suitable for sensing gases in the harsh environment of an automobile exhaust system. The device features a ceramic substrate and a glass layer to adhere a catalyst support to the substrate. A catalyst layer of either platinum or rhodium is deposited on the catalyst support and a thermally sensitive resistor element detects reactions of hydrocarbons or nitrogen oxides on the corresponding catalyst.