A cyclone includes a hollow cylindrical upper portion and a hollow conical lower portion having an inclined wall and a base wall. The base wall and the inclined wall are continuous contact with each other, and the inclined wall of the hollow conical lower portion is in continuous contact with an outer wall of the hollow cylindrical upper portion. A total cyclone height is from about 10 to about 30 millimeters, and a ratio of the total cyclone height to an inner diameter of the hollow cylindrical upper portion is from about 0.7 to about 1.3. An angle between an inner surface of the base wall and an inner surface of the inclined wall is from about 110 to about 130 degrees.

A gas analyzer and a method for performing mass spectrometry analysis includes a membrane configured to receive an input flow of carrier gas. The membrane defines a variable thickness region between first and second positions along an input face of the membrane and separates the analyte sample into an output flow of analyte molecules. A mass spectrometer is disposed downstream of the membrane and includes an input orifice for receiving the output flow. The mass spectrometer is configured to perform a response profile analysis of the analyte molecules in the sample analyte.

A gas monitor configured to monitor at least one target gas in an environmental mixture, by separating and concentrating the target gas and then adjusting for the concentration factor. The adjustment may also take into account sensor sensitivities to other gases. Methods for adjustment of target gas results and increasing accuracy of monitoring are described.

A measurement station for measuring airborne molecular contamination includes at least one gas analyser, at least two controllable isolation valves connected in parallel to the input of the at least one gas analyser, a conditioning pump, at least two calibrated orifices connected in parallel to the input of the conditioning pump, at least one distributor to connect each controllable isolation valve with, on one side, a sampling line and, on the other side, a calibrated orifice, and a control unit linked to the controllable isolation valves. The control unit commands the opening or the closing of the controllable isolation valves in order to be able to connect the at least one gas analyser with at least one sampling line.

A gas detector comprises a metal oxide semiconductor gas sensor whose resistance decreases in reducing gases and a digital information processing device that treats the output of the gas sensor and compares the output with a comparison value for gas detection. The digital information processing device extracts data representing the resistance of the gas sensor in air from the output of the gas sensor and generates the comparison value such that the larger the resistance of the gas sensor in air is, the larger the ratio between the resistance of the gas sensor in air and a resistance value corresponding to the comparison value is.

The invention relates to a sensor device (1) for detecting a gas (G), particularly a permanent gas such as H.sub.2, CO, CO.sub.2, CH.sub.4, comprising: an adsorption filter (30) comprising a body (2) consisting of a molecular sieve material, a sensing element (10) for detecting said gas (G), and a carrier (4) for carrying the sensing element (10), wherein the carrier (4) comprises an opening (50) via which said gas (G) to be detected can reach the sensing element (10), and wherein the adsorption filter (30) is connected, particularly glued, to the carrier (4) and closes said opening (50) so that said gas (G) to be detected can diffuse through said body (2) towards the sensing element (10).

The present application provides a hazardous gas detection system to determine hazardous gas concentrations and/or temperatures within a flow of exhaust air in an exhaust duct of a gas turbine compartment. The hazardous gas detection system may include one or more sensors positioned within or in communication with the exhaust duct and a static mixer positioned upstream of the one or more sensors to promote mixing of the flow of exhaust air.

According to an example aspect of the present invention, there is provided a method for preparing a gaseous isotope reference, the method comprising: providing a solid or liquid carbon-containing material exhibiting a carbon isotope ratio; providing oxygen gas or a gas mixture comprising oxygen gas, wherein said gas or gas mixture exhibits an oxygen isotope ratio; determining said carbon isotope ratio in the solid carbon-containing material and/or determining said oxygen isotope ratio in the oxygen gas or the gas mixture comprising oxygen; bringing the solid carbon-containing material in contact with the oxygen gas or the gas mixture comprising oxygen gas, in a high temperature in order to oxidize at least a part of the solid carbon-containing material to carbon dioxide to obtain the gaseous carbon and/or oxygen isotope reference in the form of carbon dioxide.

The gas measurement device includes a gas sensor disposed in a gas chamber, a filter configured to control passing gas molecules to the gas chamber, and a driving unit configured to move at least a part of a member defining the gas chamber.

A sensor element for detecting a specific gas concentration in a measurement-object gas includes: an element body provided with a measurement-object gas flow section therein, the measurement-object gas flow section introducing the measurement-object gas and causing the measurement-object gas to flow therethrough; a reference electrode disposed inside the element body; and a reference-gas introduction section that causes a reference gas to flow to the reference electrode, wherein the reference-gas introduction section has a reference-gas flow path, and one or more preliminary chambers which are disposed in a middle of the reference-gas flow path, and have a diffusion resistance lower than a diffusion resistance of the reference-gas flow path, and at least part of the reference-gas flow path is composed of a porous body so that any of the one or more preliminary chambers does not directly communicate with an outside of the element body.