A concentration measurement device 100 includes a light source 22 for generating incident light to a measurement space 10A, a photodetector 24 for receiving light emitted from the measurement space, and an arithmetic control circuit 26 for calculating a concentration of a measurement fluid on the basis of an output of the photodetector, and the light source includes a first light-emitting element 22a for generating light having a first wavelength, and a second light-emitting element 22b for generating light having a second wavelength, and the concentration measurement device is configured so as to calculate the concentration using either light of the first wavelength or the second wavelength on the basis of the pressure or temperature of the measurement fluid.

Improved gas leak detection from moving platforms is provided. Automatic horizontal spatial scale analysis can be performed in order to distinguish a leak from background levels of the measured gas. Source identification can be provided by using isotopic ratios and/or chemical tracers to distinguish gas leaks from other sources of the measured gas. Multi-point measurements combined with spatial analysis of the multi-point measurement results can provide leak source distance estimates. Qualitative source identification is provided. These methods can be practiced individually or in any combination.

A concentration measuring device 100 comprises: a measurement cell 4 having a flow path, a light source 1, a photodetector 7 for detecting light emitted from the measurement cell, and an arithmetic circuit 8 for calculating light absorbance and concentration of a fluid to be measured on the basis of an output of the photodetector, the measurement cell includes a cell body, a window portion 3 fixed to the cell body so as to contact the flow path, and a reflective member 5 for reflecting light incident on the measurement cell through the window portion, the window portion is fixed to the cell body 40 by a window holding member 30 via a gasket 15, an annular sealing protrusion 15a is provided on a first surface of the gasket for supporting the window portion, and an annular sealing protrusion 42a is also provided on a support surface 42 of the cell body for supporting the second surface opposite to the first surface of the gasket.

An in-situ gas-measuring system (1) includes an IR photon source (10) and an IR photon detector (11). The in-situ gas-measuring system (1) has an expansion chamber (12), at which an optical element (16, 16′, 16″) is arranged. A connection element (13) provides a detachable fluid-communicating connection of the expansion chamber (12) to a gas reaction chamber (2). The IR-photon source (10), the optical element (16, 16′, 16″) and the IR photon detector (11) define an optical measuring path, which extends through the expansion chamber (12). The installation and maintenance of the in-situ gas-measuring system (1) are reduced by the features of the in-situ gas-measuring system (1).

Gas detection apparatus for the detection of a target gas in a gas mixture, having a radiation source, a first measurement chamber and a second measurement chamber, as well as a first and second measurement detector. A first gas mixture flows through the first measurement chamber, and a second gas mixture flows through the second measurement chamber. Electromagnetic radiation emitted by the radiation source passes initially through the first measurement chamber and subsequently through the second measurement chamber. The first measurement detector registers a physical effect in the first measurement chamber, this physical effect correlating with the intensity of the radiation passing through the first measurement chamber, and generates a first signal correlating with the physical effect. The second measurement detector is correspondingly configured for the second measurement chamber. A second measurement point is thus provided without requiring a second radiation source.

An optical gas concentration measurement apparatus is disclosed. The optical gas concentration measurement apparatus includes a thermally insulated enclosure that has a gas sample cell situated within. A thermally-insulating, light-guiding element passes through an access port of the thermally insulated enclosure and is configured to direct light from a light source outside of the thermally insulated enclosure to the gas sample cell. A light detector outside of the thermally insulated enclosure is optically coupled to the gas sample cell and an electronic assembly outside of the thermally insulated enclosure is configured to receive information from the light detector.

Systems and methods are described, and one method includes providing an optical fiber extending into a chamber with a volume of the gas; passing an optical beam, from an optical source, through the optical fiber; applying a spectral analysis to the optical beam as received after passing through the optical fiber, and outputting a corresponding spectral analysis signal; and determining, based on the output spectral analysis signal, whether a liquid is carried by the volume of the gas.

A concentration measurement device 100 includes a light source 22 for generating incident light to a measurement space 10A, a photodetector 24 for receiving light emitted from the measurement space, and an arithmetic control circuit 26 for calculating a concentration of a measurement fluid on the basis of an output of the photodetector, and the light source includes a first light-emitting element 22a for generating light having a first wavelength, and a second light-emitting element 22b for generating light having a second wavelength, and the concentration measurement device is configured so as to calculate the concentration using either light of the first wavelength or the second wavelength on the basis of the pressure or temperature of the measurement fluid.

A concentration measurement device 20 for measuring the concentration of the a gas flowing through a junction block 14 connected to a plurality of gas supply lines includes a light source 40 for generating light incident to a flow path formed in the junction block, a photodetector 44 for receiving light emitting from the flow path, and an arithmetic control circuit 46 for determining the concentration of the gas flowing through the flow path based on the output of the photodetector, translucent incident windows 26 and 23 for making light from the light source incident to the flow path and, at least one of the translucent emitting windows 28 and 23 for emitting light passing through the flow path being sealed and fixed to the junction block 14.

The concentration measurement device 100 includes an electric unit 20 having a light source 22 and a photodetector 24, a fluid unit 10 having a measurement cell 1, optical fibers 11 and 12 for connecting the electric unit 20 and the fluid unit 10 and is configured to measure the concentration of the fluid in the measurement cell by detecting the light incident from the light source 22 to the measurement cell and then emitted from the measurement cell by the photodetector 24, where optical connection parts 32 and 34 connected to the optical fibers 11, 12 and the light source 22 or the photodetector 24 are integrally provided in the electric unit 20.