Abstract: In an exemplary embodiment, the present invention provides an exhaust constituent sensor comprising a planar sensing element securely held in place within a tubular inner shield by known methods. Improved thermal management of the sensor is provided by disposing a thermally conductive material between said planar sensing element and said tubular shield. In an exemplary embodiment, the thermally conductive material comprises a high thermal conductivity metal mesh which transfers heat within said tubular shield to said tubular shield via thermal conduction. The heat is then dissipated into the surrounding environment via thermal convection at an outer surface of the tubular shield. By optionally disposing an annular heat fin on the outer surface of the tubular shield, a greater amount of heat is dissipated into the surrounding environment via thermal convection in less time.

Abstract: The present invention provides a gas sensor element having properties capable of detecting methane and carbon monoxide selectively with 1 sensor by improving gas selectivity of the semiconductor gas sensor. The present invention relates to a gas sensor element, which has a carbon monoxide sensor layer with an ability to function as a catalyst film that blocks carbon monoxide, which impedes detection of methane at the underlying methane sensor, and has a layer-built structure where the surface of a methane sensor is covered with the carbon monoxide gas sensor which can be obtained by a gas-phase method.

Abstract: A resistance component of a sensor element for an air-fuel-ratio sensor is determined from a sensor current detected before changing an applied voltage to the sensor and a sensor current detected when a predetermined period elapses after changing the applied voltage to the sensor. A resistance component detecting apparatus includes operational amplifiers, resistors and transistors. The applied voltage is changed by switching the transistors. Accordingly, the resistance component of the sensor element is detected accurately.

Abstract: A sensor for determining an oxygen content of an exhaust gas of an internal combustion engine includes a flat-plate sensing element that is inserted in a gas-tight fashion via a hybrid seal in a ceramic shaped element that is arranged in a metal housing. The seal includes a powdered sealing packing, both placed around the sensing element in a recess at one end of the ceramic shaped element and a fusible glass seal located above the powdered sealing packing. The seal achieves gas-tight and gasoline-resistant isolation or immobilization of the sensing element in the ceramic shaped element.

Abstract: The present invention discloses an integrated ethanol gas sensor and fabrication thereof. The present invention utilities micro electro mechanical system (MEMS) technology and has a main sensing part in the form of a cantilever-bridge structure made of SiC thin film material arranged over a silicon substrate. The present invention integrates an SiC heater of comb or finger electrode shape and an SnO.sub.2 thin film gas sensing element applied over distinct portions on the same Si substrate together with Al2O3 and SnO2 thin films via a VLSI technology.

Abstract: A sensor is constituted by joining a pair of electrodes to a sensor body formed by binding hydrogen occluding metal with binders. Change in the electric resistance between the electrodes and the quantity of hydrogen occluded by the hydrogen occluding metal in the sensor body has a one to one relationship. Therefore, the quantity of hydrogen occluded by the hydrogen occluding metal can be estimated from the resistance value obtained by the sensor.

Abstract: An encapsulating device having a material encapsulated therein comprises a asic body provided with a recess for receiving therein the material and formed by microsystem technology in such a way that the material is fully arranged within the recess. A diaphragm extends across the basic body and is implemented in microsystem or thin-film technology. The diaphragm is used for encapsulating the material in the recess of the basic body in such a way that the diaphragm extends in spaced relationship with the material. An electrically actuable heating means is provided for destroying the diaphragm so as to expose the material.

Abstract: Systems and methods are described for providing a hydrogen sensing element with a more robust exposed metallization by application of a discontinuous or porous overlay to hold the metallization firmly on the substrate.

Abstract: A porous Al.sub.2 O.sub.3 thick film covers the SrTiO.sub.3 layer of an oxygen sensor, said SrTiO.sub.3 layer being contacted by means of two Pt electrodes and deposited on an Al.sub.2 O.sub.3 substrate. The electrically insulating Al.sub.2 O.sub.3 layer bears a protective layer, which is exposed to the exhaust gas and is preferably also made of SrTiO.sub.3. This construction ensures that the output signal of the sensor representing the oxygen partial pressure then depends only on the resistance or, respectively, conductivity value of the non-contaminated SrTiO.sub.2 sensor layer.

Abstract: In a gas sensor which uses CuO as a p-type semiconductor, by adding Na.sub.2 CO.sub.3 in excess of 1 wt % relative to CuO, sensitivity to gases such as H.sub.2, NO, NO.sub.2 and SO.sub.2 is suppressed, whereby selectivity for CO is increased. Sensitivity to CO.sub.2 can also be obtained. In addition, by adding a sodium salt of tungstic acid or molybdic acid, CO.sub.2 sensitivity can be made lower than the CO sensitivity, and CO gas in the exhaust gases discharged from gas-fired water heaters or other combustion equipment can be selectively detected. It is therefore possible to detect incomplete combustion.

Abstract: The present invention provides a gas sensor element having physical, electrical and chemical properties capable of detecting methane and carbon monoxide selectively with 1 intergrated filtering, catalyzing sensor by improving gas selectivity of the semiconductor gas sensor. The present invention relates to a gas sensor element, which has a carbon monoxide sensor layer with an ability to function as a catalyst film that blocks carbon monoxide, which impedes detection of methane, and has a layer-built structure where the surface of a methane sensor is covered with the carbon monoxide gas sensor which can be obtained by a gas-phase method.

Abstract: A measuring sensor for measuring a fluid includes a longitudinally extending housing having first and second ends and having an inlet opening at the first end for the fluid to be measured, and a sensor chip provided in the housing. The sensor chip has a sensor element provided towards the inlet opening and at least one electrically conducting contact provided towards the second end of the housing. The electrically conducting contact is connected to the exterior by a metal jacket lead having an outer metal tube, at least one internal conductor, and a mineral material for electrically insulating the at least one conductor, the outer metal tubing connected in a fluid-tight manner to the second end of the housing. In order to secure the sensor to an installation opening, a collar is welded to an outside of the housing at a selected position corresponding to a selected installation depth of the opening of the housing into the measuring opening.

Abstract: A engine exhaust gas measuring sensor having a sealing device and having a sleeve suitable for connection to a housing including a sealing element which is arranged at an end of sleeve facing away from the housing so that a reference air chamber is formed within the sleeve. The sealing element also has at least one opening extending longitudinally and at least one oblong contact which penetrates the opening and serves the purpose of establishing an electrical bond with a sensor element of the lambda probe. A glass seal is placed within the opening for the purpose of sealing and insulation. The glass seal encloses a longitudinal section of the contact located within the opening in the form of a jacket. The sealing element and the sleeve are made of metal. A method for making such an engine exhaust gas sensor includes the steps of introducing solder glass in a sealing element opening, heating the solder glass so that it becomes fluid and cooling the glass so that is solidifies or sets.

Abstract: A method and sensor for distinguishing between different optical isomers (enantiomers), which sensor comprises a pair of spaced-apart contacts and a semi-conductive polymer material spanning the gap between the contacts, which polymer material includes chiral sites. The chiral sites in the polymer material are preferably formed by incorporating an optically active counterion into the polymer material, for example by growing the polymer in the presence of such a counterion, e.g. camphor sulphonic acid.

Abstract: To manufacture integrated semiconductor devices comprising chemoresistive gas microsensors, a semiconductor material body is first formed, on the semiconductor material body are successively formed, reciprocally superimposed, a sacrificial region of metallic material, formed at the same time and on the same level as metallic connection regions for the sensor, a heater element, electrically and physically separated from the sacrificial region and a gas sensitive element, electrically and physically separated from the heater element; openings are formed laterally with respect to the heater element and to the gas sensitive element, which extend as far as the sacrificial region and through which the sacrificial region is removed at the end of the manufacturing process.

Abstract: Oxygen sensor for measuring resistance as a function of oxygen partial pressure, made of alkaline-earth-doped perovskitic lanthanum ferrites with the general formulaLa.sub.1-x Me.sub.x FeO.sub.3-.delta.where Me is one of alkaline earth metals, Mg, Ca, Sr, and Ba, x is a degree of doping of the lanthanum ferrites. The oxygen sensor oxygen deficit of anion is 6=0 to 0.25, and the degree of doping of the lanthanum ferrites is x=0.1 to 0.3 and is selected to provide a temperature independent resistance property to the oxygen sensor in a lean range.

Abstract: The invention provides a sensor arrangement for monitoring the concentrat of moisture and gaseous substances in ambient air. A gas sensitive intermediate layer is sandwiched between top and bottom electrodes, each of which comprises first and second interdigitated conductive elements, which are coupled to an opposite polarity voltage. The top and bottom electrodes are super-imposed on opposite sides of the gas-sensitive intermediate layer, with fingers of the top electrode having a voltage polarity which is opposite that of adjacent super-imposed fingers of the bottom electrode.

Abstract: The present invention relates to a solid electrolyte thin film and a manufacturing method for the same. The solid electrolyte thin film of the present invention comprises yttrium stabilized zirconia and is characterized in that the thickness of the film is 10 to 50 .mu.m. In an embodiment, 80% or more of the surface area of the film is occupied by crystals having a crystal grain size of 6 to 18 .mu.m. The present invention also includes a method for producing a solid electrolyte thin film comprising a sintered body of solid electrolyte powders. The method includes regulating the grain size of said solid electrolyte powders in the range of 0.1 to 5.0 .mu.m; preparing a slurry solvent by mixing a binder and other materials with a solvent containing 10 to 80 wt % of a low volatile solvent, and mixing the slurry solvent with the solid electrolyte powder; and coating the obtained slurry onto a substrate. The slurry composition is prepared so that it has a viscosity in the range of 1 to 500 cps.

Abstract: An NO.sub.x sensor is produced by sintering a plurality of columnar crystals of .beta.-type Nb.sub.2 O.sub.5. The average value M of aspect ratios b/a (wherein a represents a width and b represents a length) in the columnar crystals is set in a range of 2.11<M.ltoreq.5. The NO.sub.x sensor has a high sensitivity to NO.sub.x via an enhancement attained by control of crystal type and structure.

Abstract: A coating for the structured production of conductors on the surface of electrically insulating substrates, in particular for producing sensor elements and printed circuit boards. The coating is formed from a doped tin oxide layer having the composition Sn.sub.1-(y+z) A.sub.y B.sub.z O.sub.2, in which A is Sb or F and B is In or Al. The relative proportions in the coating of the dopants antimony (or fluorine) and indium (or aluminum) are defined by the limits 0.02<y+z<0.11 and satisfy the condition 1.4<y/z<2.2. The coating can be structured by ablation using electromagnetic laser radiation in the wavelength range 157-1064 nm. The creates an economical means for high resolution and waste-free structuring of insulating channels in thin, electrically conductive layers having high chemical, mechanical and thermal resistance on glass or ceramic substrates.

Abstract: A polymeric gas sensor utilizes a variety of electrode geometries to generate varied responses to selective gases. The characteristic response to various gases of each electrode geometry permits the construction of a gas sensor having desirable and reproducible characteristic responses to specific gases. The gas sensor array of the invention produces characteristic responses from a plurality of sensors. These responses collectively produce a characteristic response pattern that can be used for the identification of specific gases with pattern recognition techniques.

Abstract: A combustible gas sensor having a pair of temperature sensor sections is here disclosed. One of the pair of temperature sensor sections is covered with porous oxidizing catalytic layers (23, 24) for oxidizing a combustible gas, and the other is not covered with the oxidizing catalyst layers. In the one temperature sensor section, the combustible gas is burned, and in the other temperature sensor section, the temperature of a gas to be measured is compensated. The temperature sensor sections each comprises temperature sensitive portions (13, 14) made of a dense ceramic material, resistors (21, 22) buried therein and having a positive resistance temperature coefficient, current leads (31, 32, 41, 42) and voltage leads (33, 34, 43, 44). A method for measuring the concentration of the combustible gas by the use of this combustible gas sensor is also disclosed.

Abstract: A resistive gas sensor has a gas sensing layer (11) overlaid as a layer on an array of electrodes (12, 14, 16) with unequal gaps (22, 24) between them. Signals from the different electrodes represent resistances in different regions of the sensing layer. The layer is applied as a succession of sub-layers, with application of each sub-layer modifying the microstructure of the preceding sub-layers. The resulting variation in microstructure within the sensing layer (11) is used for distinguishing between a reactive gas and a less reactive gas. The sensor has domestic applications for carbon monoxide detection.

Abstract: A thin film hydrogen sensor, includes: a substantially flat ceramic substrate with first and second planar sides and a first substrate end opposite a second substrate end; a thin film temperature responsive resistor on the first planar side of the substrate proximate to the first substrate end; a thin film hydrogen responsive metal resistor on the first planar side of the substrate proximate to the fist substrate end and proximate to the temperature responsive resistor; and a heater on the second planar side of the substrate proximate to the first end.

Abstract: A semiconductor chemical sensor device (2) comprises a sensitive layer (4) for detecting specific chemicals and a heater for heating the sensitive layer, which is formed by a heater portion (6) of a conductive layer (8) in the semiconductor chemical sensor device (2). The semiconductor chemical sensor device (2) further comprises a thermocouple (12) for detecting the temperature of the sensitive layer (4), the thermocouple comprising a P/N junction (14) formed as part of or adjacent the heater portion (6) of the conductive layer (8) such that a signal developed across the P/N junction (14) is representative of the temperature of the sensitive layer (4).

Abstract: The invention is a sensing method and an oxygen sensor for detecting a change of oxygen partial pressure in an ambient atmosphere through a change of a measurable physical property of a sensing material. The sensor includes a sensing material selected from metal or its oxides which, when at an elevated temperature and exposed to a gas containing a changing partial pressures of oxygen, is capable of changing from one metal or metal oxide phase to another such oxide phase and vice versa. Associated with such phase change is a change in a measurable physical property of the material. The sensor also includes an electrical heating source, connectable to a power source, maintaining a temperature gradient across the sensing material since it is critical that the sensing material exist in at least two phases during active sensing.

Abstract: A high-temperature gas sensor for the detection of the heat tone of combustible gases includes a semiconducting ceramic layer with thermistor properties. The semiconducting ceramic layer is formed of an oxide ceramic semiconducting material having a defined crystalline structure and a thermistor characteristic of high sensitivity. A process for the manufacture of the high-temperature gas sensor includes sintering a loosely structured layer of powder particles of an oxide semiconductor with both a defined composition and high sinter activity for achieving a required high porosity of a semiconducting ceramic layer with thermistor properties.

Abstract: An air fuel ratio sensor has a sensor element having a sensing portion and a flange portion in contact with a tapered portion of an accommodation hole of a housing. The sensor element is hot crimped at a hot crimping portion of a housing. At least the hot crimping portion is made of a ferritic stainless steel formed by cold forging and having a composition content comprising a total amount of C and N impurities of 0.03 wt % or below. The average hot crimping temperature of the housing is performed at lower than 1000.degree. C. as applied for a time period of one second or less.

Abstract: An oxygen sensor made of alkaline-earth-doped perovskitic lanthanum ferrites with the general formula:La.sub.1-x Me.sub.x FeO.sub.3-.delta.where Me is one of the alkaline earth metals, Mg, Ca, Sr, and Ba and x is the degree of doping, and the oxygen deficit of anion .delta.=0 to 0.25. The degree of doping of the lanthanum ferrites is x=0.1 to 0.3 and resistance is measured in the lanthanum ferrites as a function of oxygen partial pressure.

Abstract: A sensor has a voltage output circuit and a potentiometric resistor for dividing the voltage of the voltage output circuit. The resistance of the potentiometric resistor is regulated by trimming in order to regulate the output voltage of the sensor. A sensor has a voltage output circuit and a serial resistor connected in series with the voltage output circuit. The total resistance of the voltage output circuit and the serial resistor is regulated by trimming so as to have a certain relation with the output voltage of the voltage output circuit. The resistance of the potentiometric resistor or the serial resistor may be 100 times or more as much as the resistance of the voltage output circuit. The voltage output circuit may comprise a resistor having a positive resistance temperature coefficient, a semiconductor whose resistance changes in accordance with a gas concentration, or a piezoelectric element for converting a stress into a piezoelectric signal.

Abstract: In order to avoid measurement signal drift, a gas sensor has a gas sensitive layer which is provided on its upper side with a measuring electrode structure and on its lower side with an electrically conductive layer.

Abstract: A film heater and thick-film electrode pads are provided on one main surface of a heat-resistant insulating substrate and are connected by through holes to a metal oxide semiconductor film on the tail surface. Pads are made of a gold alloy such as Au--Pt and connected to leads of Pt--W, etc.

Abstract: A substrate carrying a first electrode and a second electrode, the first and second electrodes being disposed adjacent to one another, the first electrode being disposed between the substrate and a gas-sensitive component, the gas sensitive component comprising an n-type semiconductor, the gas-sensitive component having a resistance that is gas-dependent and temperature-dependent, and the second electrode being disposed between the substrate and a non-gas-sensitive component, the non-gas-sensitive component comprising a n-type semiconductor and a p-type semiconductor, the non-gas-sensitive component having a resistance that is temperature-dependent and that is not gas-dependent and wherein the n-type semiconductor of the non-gas-sensitive component is Ga.sub.2 O.sub.3 and the p-type semiconductor of the non-gas-sensitive component is ZrO.sub.2.

Abstract: A gas sensor includes a one-piece housing sleeve having a length dimension; an exhaust gas-side end and an opposite, exhaust gas-remote end, an inner space, an external thread, a terminal length portion which includes the exhaust gas-side end and which is exposable to an exhaust gas and a shoulder extending along an entire inner circumference of the housing sleeve at the terminal length portion thereof. A protecting sleeve which is disposed in the terminal length portion has a sealing collar seated on the shoulder of the housing sleeve. A ceramic supporting member is disposed in the inner space and has a throughgoing aperture parallel to the length dimension of the housing sleeve. The ceramic supporting member separates the inner space into a reference gas chamber and an exhaust gas chamber. The exhaust gas chamber is surrounded by the terminal length portion of the housing sleeve. A sensor element passes through and is fixedly held in the throughgoing aperture of the ceramic supporting member.

Abstract: Cuprate mixed oxides having the general formula Ln.sub.2 CuO.sub.4+y, in which Ln stands for at least lanthanum or a trivalent element from the group of rare earths with atomic numbers from 58 to 71, and the O.sub.2 stoichiometric deviation y lies in the 0.001 to 0.1 range, are particularly suitable for use in oxygen sensors, for example in exhaust gas systems.

Abstract: A semiconductor device (50) comprises a semiconductor base, a heater (20) formed over the semiconductor base from conductive material, such as polysilicon, and a layer (22) for heating by the heater. The heater (20) comprises first (24) and second (26) arms extending over the semiconductor base from a heater portion (28) and an opening (34) extending vertically through the heater portion (28). A first heater contact (30) is coupled to an end of the first arm (24) and a second heater contact (32) is coupled to an end of the second arm (26). The layer (22) is formed over the opening (34) and heater portion (28) such that a vertical axis through the center (36) of the opening (34) extends through the center (36) of the layer (22).

Abstract: Air pollution gas sensor which efficiently detects smell from smoking, ordinary stinks such as TMA and CH3SH, smell of Kimchi, acetaldehyde, and etc. and also a method for fabricating the same is revealed and described including a substrate, a heater formed on said substrate, electrodes each formed on said substrate insulated from the heater, and a sensing layer formed of SnO.sub.2, including WO.sub.3 on said substrate including said electrodes, with the method for fabricating the gas sensor including the steps of forming the heater on the substrate, forming the electrodes on the substrate insulated from the heater, and forming a sensing layer of SnO.sub.2 including WO.sub.3 on the substrate including the electrodes.

Abstract: The invention concerns a method and measuring device for determining the water content of a gas. The measuring device comprises a measuring sensor arrangement which consists of: a capacitive sensor thermally coupled to a heating element and to a temperature sensor; an energy source connected to the heating element; a first evaluation circuit connected to the temperature sensor. The heating element and the temperature sensor are formed by a common temperature-dependent resistor. Together with the temperature dependent resistor and the energy source, the second evaluation circuit forms a control circuit for keeping the temperature of the capacitive sensor constant. As a function of the capacity of the capacitive sensor as the sole variable the first evaluation circuit determines the actual value of the relative humidity of the gas from previously determined calibrating values at the same constant temperature by interpolation or extrapolation of the calibrating values.

Abstract: A method of manufacturing a nitrogen oxide sensor for detecting a nitrogen oxide to be used in the field of e.g. reducing or decomposing nitrogen oxides, as well as such sensor and material suitable for manufacturing the sensor are disclosed. For manufacturing the sensor material, a precursor containing components for constituting the sensor material in a predetermined equivalent ratio of stoichiometry between chemical elements is prepared. First, the precurser is subjected to sintered to a preliminary sintering step. Then, the resultant sintered material is subjected to at least two cycles of main sintering step at 815.degree. to 848.degree. C. (T1) with an intermediate grinding step of the sintered material therebetween, thus obtaining the gas detecting portion comprised mainly of oxide compound having a composition represented by:Bi.sub.2 Sr.sub.2 YCu.sub.2 O.sub.8+y(0.ltoreq.y.ltoreq.1)and having the 2212 phase of crystal structure.

Abstract: A hydrocarbon gas detection device operates by dissociating or electro-chemically oxidizing hydrocarbons adsorbed to a silicon carbide detection layer. Dissociation or oxidation are driven by a varying potential applied to the detection layer. Different hydrocarbon species undergo reaction at different applied potentials so that the device is able to discriminate among various hydrocarbon species. The device can operate at temperatures between 100.degree. C. and at least 650.degree. C., allowing hydrocarbon detection in hot exhaust gases. The dissociation reaction is detected either as a change in a capacitor or, preferably, as a change of current flow through an FET which incorporates the silicon carbide detection layers. The silicon carbide detection layer can be augmented with a pad of catalytic material which provides a signal without an applied potential. Comparisons between the catalytically produced signal and the varying potential produced signal may further help identify the hydrocarbon present.

Abstract: 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.

Abstract: A hydrogen sensitive metal alloy contains palladium and titanium to provide a larger change in electrical resistance when exposed to the presence of hydrogen. The alloy is deposited on a substrate and a thin film and connected across electrical circuitry to provide a sensor device that can be used for improved sensitivity and accuracy of hydrogen detection.

Abstract: A sensor including a micro-bridge heater which is located above a depression in the surface of a substrate. The heater includes a first insulating film on the substrate, a conductive film on the first insulating film, and a second insulating film on the conductive film. The first and second insulating films are made of the same material, preferably tantalum oxide (Ta.sub.2 O.sub.5) and are the same thickness. A foundation film is not employed as an adhesive between the first insulating film and the conductive film due to the strong adherence between the first insulating film and the conductive film which is preferably made of platinum or a platinum alloy. Because the first and second insulating films are made of the same material and have the same thicknesses, the insulating films have similar rates of thermal expansion and the expansion or contraction of the insulating films offset each other, thus reducing the thermal stress imposed on the conductive film.

Abstract: A gas sensing apparatus is disclosed including a gas sensing device that is self-heated due to an applied voltage, whose resistance variation amount is varied to thereby sense gas; a voltage supply for variably supplying a voltage to the gas sensing device; a current detector for detecting the current flowing through the gas sensing device thereby generating a current-voltage characteristic for the gas sensing apparatus under the effect of a given gas exposure; and a control and judgement portion for controlling the voltage supply to control a variation value of a voltage supplied to the gas sensing device and to determine the kind and density of a gas in an ambient atmosphere, using current-voltage characteristic reference data.

Abstract: A sensor is proposed for detecting nitrogen oxides (NO, NO.sub.2, N.sub.2 O.sub.4) in a test gas, having a semiconducting metal oxide layer (3) which is deposited on a ceramic substrate (10) and whose electrical resistance provides information about the concentration of nitrogen oxides (NO, NO.sub.2, N.sub.2 O.sub.4) in the test gas. The main components of the sensor are a converter layer (4) which is deposited on the metal oxide layer (3) and is made of a material which causes the oxidation of combustible components of the test gas and converts the nitrogen monoxide (NO) contained in the test gas into nitrogen dioxide (NO.sub.2) or dinitrogen tetroxide (N.sub.2 O.sub.4), which then reaches the metal oxide layer (3), as well as a heating device (5) which heats the metal oxide layer (3) and the converter layer (4). The converter layer is suitably constituted of titanium oxide (TiO.sub.2) and/or zirconium oxide (ZrO.sub.2) and/or silicon oxide (SiO.sub.2) and/or aluminum oxide (Al.sub.2 O.sub.

Abstract: The invention includes a sealing system for a heated flat plate exhaust gas sensor having a plurality of alternating layers of glass and steatite surrounding a flat plate sensing element. A ceramic tube surround the plurality of layers. The ceramic tube is carried in a tubular-shaped metal housing.

Abstract: A thin-film gas sensor and manufacturing method of the same is disclosed which includes a silicon substrate; an insulating layer formed on the surface of the silicon substrate; a heater formed in zigzag on the surface of said insulating layer; a temperature sensor formed in zigzag on the surface of the insulating layer in parallel with the heater; an interlayer insulating layer for electrically insulating the heater and temperature sensor formed on the insulating layer; a plurality of electrodes formed on the interlayer insulating layer placed between the heater and temperature sensor; a plurality of pairs of gas sensing layers disposed in an array on the electrodes and for reacting on detected gas; and a plurality of gas shielding layers formed on one gas sensing layer out of the pair of gas sensing layers and for shielding the detected gas so that the gas sensing layers do not react on the detected gas.

Abstract: A thermistor type temperature sensor having a substrate made from an electrically insulating ceramic plate. A thin or thick film detecting resistor is printed on the substratum. A thick or thin film pull-up resistor may also be printed on the substratum, and trimming of the resistors is possible. The ratio of B-constant values for the detecting resistor and the pull-up resistor may be selected so that it is locate between 0.4 to 0.9 or 1.1 to 1.5. The detecting resistor may be constructed from thermistor sections of the same composition and the sections may be connected in parallel or in series. The thermistor sensor can be connected to the pipe through which a gas passes. When the sensor is connected to the pipe, the angle of the measuring plane may be adjusted, so that a precise measurement can be obtained.

Abstract: A valve stem gas leak sensor or detector configured to surround a possibly leaking petrochemical or like flow line valve stem and provide for external monitoring equipment an electrical resistance related to the amount of hydrocarbon gas leakage occurring around the valve stem. Such a gas leak detector, termable a ring sensor, is configured as a stem surrounding enclosure, with interconnecting segments for ease of installation around and removability from a valve stem, with one or both of each such segments having an interiorly arranged layer of gas sensor particulate material characterized by change in electrical resistance in the presence of a changing concentration of hydrocarbon gas leakage around a valve stem, and with interengaging connector/conductor pins holding the segments together around the valve stem and across which the electrical resistance of one or both gas sensor material layers can be measured with the ring sensor in place on the valve stem.

Abstract: A metal-insulator-semiconductor diode sensor having a Pt/Ir alloy and/or a Pt/Sn alloy electrode is sensitive to and can detect ethylene. An array of metal-insulator-semiconductor diode sensors having varying sensitivity responses can indicate a fault in an electrical transformer by the detection of at least one of the key fault gases CO, H.sub.2, C.sub.2 H.sub.2 and C.sub.2 H.sub.4.