A gas measurement system as disclosed can include a coherent light source, which emits a light beam; a detector; a beam path formed between the light source) and the detector; and a gas cell arranged in the beam path such that the detector receives light transmitted through the gas cell. The gas cell can include a porous ceramic and have an optical path length which is a multiple of the actual layer thickness of the gas cell. A optical element can be arranged in the beam path between the light source and the gas cell with the light beam emitted by the light being widened and unfocussed as the light beam enters the gas cell.

A method and apparatus are described for measuring the concentration of a gas with an absorption band in the ultraviolet range. The device includes an absorption chamber containing a gas, a light source, a selected optical bandpass filter, and ultraviolet photodetectors. The gas concentration is measured by the ratio of a transmitted intensity to an incident intensity with the Beer-Lambert Law relation. A second light source may be used for a compensation signal. A second method periodically changes the absorption coefficient by inserting a transparent material in the absorption path to measure the optical compensation signal. A third method periodically shortens the optical absorption path by moving the active detector closer to the light source to measure the optical compensation signal. The fourth method uses an optical element to deflect the optical beam to create a shorter absorption path as a reference for the incident signal using one detector.

A concentration measurement method is performed using a concentration measurement device comprising: a measurement cell for flowing a fluid to be measured; a light source for generating light incident on the measurement cell; a photodetector for detecting light emitted from the measurement cell; an arithmetic unit for calculating the absorbance and concentration of the fluid to be measured based on an output of the photodetector; and a temperature sensor for measuring the temperature of the fluid to be measured. The concentration measurement method includes: a step of flowing a gas whose molecular structure varies with the temperature as the fluid to be measured in the measurement cell; a step of making light of a wavelength absorbable by the fluid to be measured to be incident from the light source to the measurement cell; a step of measuring the intensity of light emitted from the measurement cell by the photodetector; and a step of calculating the concentration of the fluid to be measured based on the temperature and the output of the photodetector measured by the temperature sensor.

A combustion-zone chemical sensing system (100) is disclosed that includes pitch reflective optics (110) that collimate MIR electromagnetic energy from an input fiber (150), a reflector (120), catch reflective optics (112) that focus reflected MIR electromagnetic energy into an output fiber (152), and a detector (140) to detect MIR electromagnetic energy from the output fiber. An optical head (102) for sensing a combustion zone (104) is disclosed that includes pitch reflective optics (110) that collimate MIR electromagnetic energy from an input fiber (150) towards a reflector (120), catch reflective optics (112) that focus MIR electromagnetic energy, reflected from the reflector, into an output fiber (152), and an alignment housing that interfaces with structure adjacent the combustion zone. A method for determining gas concentration within a combustion zone is disclosed that includes collimating MIR electromagnetic energy exiting from an input fiber to traverse a combustion zone and focusing reflected MIR electromagnetic energy from the combustion zone into an output fiber.

A gas analyzer that easily facilitates alignment is provided. The gas analyzer is a gas analyzer for measuring a predetermined component in a measurement gas by irradiating light on the measurement gas from a light emitting element and receiving light that passes through the measurement gas. The gas analyzer includes a base member configured to be adjustable in position along at least one axis that is not parallel to the optical axis of the light emitting element, and a holding member configured to hold the light emitting element and to be held to the base member in an angularly adjustable manner around at least one axis that is not parallel to the optical axis.

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.

A concentration measurement method is performed using a concentration measurement device comprising: a measurement cell for flowing a fluid to be measured; a light source for generating light incident on the measurement cell; a photodetector for detecting light emitted from the measurement cell; an arithmetic unit for calculating the absorbance and concentration of the fluid to be measured based on an output of the photodetector; and a temperature sensor for measuring the temperature of the fluid to be measured. The concentration measurement method includes: a step of flowing a gas whose molecular structure varies with the temperature as the fluid to be measured in the measurement cell; a step of making light of a wavelength absorbable by the fluid to be measured to be incident from the light source to the measurement cell; a step of measuring the intensity of light emitted from the measurement cell by the photodetector; and a step of calculating the concentration of the fluid to be measured based on the temperature and the output of the photodetector measured by the temperature sensor.

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, a first light-transmission member 11 for transmitting light from the light source to the measurement cell, a second light transmission member 12 for transmitting light from the measurement cell to the photodetector, a lens 3A provided in the fluid unit, the lens 3A being arranged such that light from the first light transmission member is to be incident on the first position and light is to be emitted from the second position to the second light transmission member, a pressure sensor 5 for measuring pressure of fluid flowing through the measurement cell, and an arithmetic circuit 28 for detecting concentration of the fluid flowing through the measurement cell, the arithmetic circuit being configured to calculate the fluid concentration based on the output of the photodetector and a correction factor related to the pressure output by the pressure sensor and the concentration of fluid in order to reduce the measurement error due to the refractive index of the fluid.

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.

A Concentration measurement device 100 comprises: a measurement cell 4 having a flow path through which a gas flows, a light source 1 for generating incident light to the measurement cell, a photodetector 7 for detecting light emitted from the measurement cell, a pressure sensor 20 for detecting a pressure of the gas in the measurement cell, a temperature sensor 22 for detecting a temperature of the gas in the measurement cell, and an arithmetic circuit 8 for calculating a concentration of the gas based on an output P of the pressure sensor, an output T of the temperature sensor, an output I of the photodetector, and an extinction coefficient α, wherein the arithmetic circuit 8 is configured to calculate the concentration using the extinction coefficient α determined on the basis of the output of the temperature sensor 22.