Provided are a gas detection method and a gas detector which have a high durability to silicone poisoning and is capable of detecting the type and the concentration of a target gas to be detected with certain accuracy even when the detector is used in an environment where a silicone compound exists. The gas detector employs a contact combustion-type gas sensor which includes two gas detection elements, each intermittently driven, and in which only one gas detection element is supplied with a gas through a silicone removal filter. Acquired in an energization duration of each of the gas detection elements are two or more pieces of output data by the one gas detection element and two or more pieces of output data by the other gas detection element, which constitutes output variation patterns for a test gas. The output variation patterns are contrasted to a reference output variation pattern of each of four largely divided types of reference gases of a paraffinic hydrocarbon gas, a solvent gas, a hydrogen gas, and an argon gas, with the reference output variation patterns being acquired in advance, thereby identifying the type of the target gas being detected in the test gas.

Provided are a gas detection method and a gas detector which have a high durability to silicone poisoning and is capable of detecting the type and the concentration of a target gas to be detected with certain accuracy even when the detector is used in an environment where a silicone compound exists. The gas detector employs a contact combustion-type gas sensor which includes two gas detection elements, each intermittently driven, and in which only one gas detection element is supplied with a gas through a silicone removal filter. Acquired in an energization duration of each of the gas detection elements are two or more pieces of output data by the one gas detection element and two or more pieces of output data by the other gas detection element, which constitutes output variation patterns for a test gas. The output variation patterns are contrasted to a reference output variation pattern of each of four largely divided types of reference gases of a paraffinic hydrocarbon gas, a solvent gas, a hydrogen gas, and an argon gas, with the reference output variation patterns being acquired in advance, thereby identifying the type of the target gas being detected in the test gas.

A gas sensing device that includes a (a) gas reactive element that has a gas dependent temperature parameter; and (b) a semiconductor temperature sensing element that is spaced apart from the gas reactive element and is configured to sense radiation emitted from the gas reactive element and generate detection signals that are responsive to a temperature of the gas reactive element; wherein the gas reactive element and the semiconductor temperature sensing element are of microscopic scale.

A gas sensing device that includes a (a) gas reactive element that has a gas dependent temperature parameter; and (b) a semiconductor temperature sensing element that is spaced apart from the gas reactive element and is configured to sense radiation emitted from the gas reactive element and generate detection signals that are responsive to a temperature of the gas reactive element; wherein the gas reactive element and the semiconductor temperature sensing element are of microscopic scale.

The present invention provides a catalytic conversion-type sensor that detects a detection target gas by detecting a conversion gas produced through a reaction, the catalytic conversion-type sensor including: a gas flow path that allows the detection target gas to flow down; and a conversion portion that is connected to the gas flow path, the conversion portion including, on a side partitioned by a diffusion means that allows the detection target gas to naturally diffuse, a heated catalyst portion that produces a conversion gas by causing the detection target gas to come into contact with a heated catalyst and react with the heated catalyst, and a sensor element portion that is capable of detecting the conversion gas produced through the reaction.

The present invention provides a catalytic conversion-type sensor that detects a detection target gas by detecting a conversion gas produced through a reaction, the catalytic conversion-type sensor including: a gas flow path that allows the detection target gas to flow down; and a conversion portion that is connected to the gas flow path, the conversion portion including, on a side partitioned by a diffusion means that allows the detection target gas to naturally diffuse, a heated catalyst portion that produces a conversion gas by causing the detection target gas to come into contact with a heated catalyst and react with the heated catalyst, and a sensor element portion that is capable of detecting the conversion gas produced through the reaction.

A method and a gas sensing device are provided. The gas sensing device may include a bulk and an array of gas sensing elements that are thermally isolated from the bulk, wherein each gas sensing element of a plurality of gas sensing elements of the array comprises (i) a gas reactive element that has a gas dependent temperature parameter; and (ii) a semiconductor temperature sensing element that is thermally coupled to the gas reactive element and is configured to generate detection signals that are responsive to a temperature of the gas reactive element.

Method and apparatus for determining a heating value of a sample hydrocarbon-containing mixture having hydrocarbons and non-hydrocarbons as mixture components. The sample is reacted with an excess amount of oxidant gas in a reaction chamber to form a product gas containing residual oxygen. The molecular weight of the sample is measured and the residual oxygen concentration of the product gas is measured. The heating value is calculated from the measurements of the molecular weight and the residual oxygen concentration. Pure component hydrocarbon gases may be used to calibrate the system.

Method and apparatus for determining a heating value of a sample hydrocarbon-containing mixture having hydrocarbons and non-hydrocarbons as mixture components. The sample is reacted with an excess amount of oxidant gas in a reaction chamber to form a product gas containing residual oxygen. The molecular weight of the sample is measured and the residual oxygen concentration of the product gas is measured. The heating value is calculated from the measurements of the molecular weight and the residual oxygen concentration. Pure component hydrocarbon gases may be used to calibrate the system.

A gas measuring device (100) and a gas measuring process measure a concentration of a combustible target gas relatively reliably. An electrical voltage (U10, U11) is applied to both a detector (10) and a compensator (11). The applied electrical voltage heats an electrically conductive segment (20) of the detector (10) and an electrically conductive segment (38) of the compensator. The heated detector segment (20) oxidizes combustible target gas (CH.sub.4), while a passivation coating on the compensator segment (38) largely prevents the compensator segment (38) from oxidizing combustible target gas (CH.sub.4). The passivation coating includes iodine. The gas measuring device (100) determines the target gas depending on the temperature of the detector segment (20) and the temperature of the compensator segment (38) when operated in an oxidation measurement mode, and depending only on the temperature of the compensator segment (38) when operated in a heat conduction measurement mode.