WO2022034152A1 - Gas detector system - Google Patents

Gas detector system Download PDF

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Publication number
WO2022034152A1
WO2022034152A1 PCT/EP2021/072420 EP2021072420W WO2022034152A1 WO 2022034152 A1 WO2022034152 A1 WO 2022034152A1 EP 2021072420 W EP2021072420 W EP 2021072420W WO 2022034152 A1 WO2022034152 A1 WO 2022034152A1
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WO
WIPO (PCT)
Prior art keywords
module
light
optical interface
gas
cavity
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PCT/EP2021/072420
Other languages
French (fr)
Inventor
Preben STORÅS
Lasse IRVAM
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Optronics Technology As
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Publication of WO2022034152A1 publication Critical patent/WO2022034152A1/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/01—Arrangements or apparatus for facilitating the optical investigation
    • G01N21/03—Cuvette constructions
    • G01N21/031—Multipass arrangements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/255—Details, e.g. use of specially adapted sources, lighting or optical systems
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/0004—Gaseous mixtures, e.g. polluted air
    • G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
    • G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/01—Arrangements or apparatus for facilitating the optical investigation
    • G01N21/03—Cuvette constructions
    • G01N21/031—Multipass arrangements
    • G01N2021/0314—Double pass, autocollimated path
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/01—Arrangements or apparatus for facilitating the optical investigation
    • G01N21/15—Preventing contamination of the components of the optical system or obstruction of the light path
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2201/00—Features of devices classified in G01N21/00
    • G01N2201/02—Mechanical
    • G01N2201/022—Casings
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2201/00—Features of devices classified in G01N21/00
    • G01N2201/02—Mechanical
    • G01N2201/024—Modular construction

Definitions

  • the present invention relates to a modular gas measuring and detection system, especially related to optical gas measurements.
  • Gas detectors of different types have been well known for a long time, for example as described in US6337741 , EP3198261 or US9678010, involving a light source transmitting a light beam through a gas and a receiver means measuring and analyzing the received light in order to detect the presence of a gas.
  • the spectrum analysis may be performed by changing the wavelength of the source, e.g. using tunable lasers, or by analyzing the received light from a known source after having passed through the gas volume.
  • the gas volume is a closed volume with input and output for providing a gas flow through the volume.
  • Point Gas Detectors measures the gas that reaches the detection point of the detector and must therefore be close to the leak point, and positioned correct relative to the wind direction.
  • Open Path Detectors consists of one unit that is emitting light and another unit that measures the light, and these two units can be placed far from each other. These two units can detect gases passing between them. This way, large areas can be "fenced" in with a few Open Path detectors effectively monitoring for gas. Using Point Detectors to monitor such an area would in many situations demand too many detectors, but may have other advantages such as being less sensitive to other materials and disturbances entering the measured area, e.g. as is discussed in international application No. PCT/EP2020/072644.
  • the gas measuring system according to the present invention is primarily a point detector, but may with some modifications be used as an open path detector depending on the use. It may be used in a number of environments such as hydrocarbon production, mining, or in ships, with necessary adaptations to the gas to be detected, to facilitate testing and calibration or to the general situation at the site, e.g. protecting against rain, mosquitos, particles etc.
  • the existing solutions are, however, not very flexible, making these adaptations.
  • the present invention provides a modular system for providing a convenient and inexpensive solution for improving the flexibility of the optical gas detector.
  • Fig. 1 a,b illustrates the preferred embodiment of the system according to the invention.
  • Fig. 2a-2d illustrates different modules to be used in the present invention.
  • Fig. 3 illustrates the cross section of a preferred embodiment of the invention.
  • Figure 1 a shows a schematic illustration of the system according to the invention including a sensor unit 4, including light source, light receiver and necessary supporting circuitry for analyzing, power supply and possibly wired and/or wireless communication with external computers and network.
  • the sensor unit 4 is per se known in the art and will not be discussed in detail here.
  • the sensor unit 4 includes a housing part 5 with a cavity or recess 1 for releasable containing a module A,B,C,D.
  • the sensor unit 4 includes an optical interface 2 on one side of the cavity 1 for directing light from the light source into the cavity and also for receiving light from the cavity 1 , the optical interface 2 may include one or more suitable windows, lenses etc. for controlling the light beam, from the light source and back into the sensor or just a defined opening.
  • cavity 1 in the housing part 5 also includes a mirror or reflector 3a, preferably a retroreflector, at the opposite end 3 of the cavity 1 thus defining a volume in which the measurements may be performed, the cavity 1 having a defined length from the optical interface 2 to the opposite end 3 preferably containing the reflector 3a.
  • the modules according to the preferred embodiment having a length corresponding to the cavity length and at least enclosing a volume defined by the light beam between the optical interface 2 and the cavity end 3.
  • the reflector may be positioned inside the module or, if used as an open path detector, at a different position.
  • the advantage of having the reflector integrated in the housing is that it maintains a consistence in the measurements which removes one variable in e.g. calibrations, which could be caused by using different reflectors in different modules.
  • the housing part 5 may be of any shape providing mechanical protection, allowing gas in the environment pass unhindered and preferably also have sealing surfaces on or preferably around the optical interface 2 and reflector 3a or cavity end 3 so as to be able to allow a module to contain a gas between the interface and reflector without adding additional elements in the optical beam path.
  • the shape of the cavity 1 may correspond directly to the shape of at least one of the modules or be larger to make sure future module types may be used. The important feature being that the light is allowed to pass unhindered through the optical interface 2 to or from the source and sensor and the reflector 3a. Referring to figure 1 b the preferred embodiment of the invention therefor has the opening in the housing for introducing the module B into the side of the housing part 5 so that the module is entered into the cavity between the optical interface on one end and the reflector on the other end.
  • the sensor unit 4 and housing 5 with reflector 3 will be capable of measuring a chosen gas in the cavity without a module mounted therein.
  • the inventive design will, however, provide the benefits of the present invention by introducing a chosen module in the cavity, e.g. for protection, calibration or testing purposes, or for connecting the cavity to a chamber of conduit leading a gas flow through the module.
  • Possible modules may come from the following list as illustrated in figures 2a, 2b, 2c, 2d where the modules include end sections 8,9 for positioning over the optical interface and reflector for allowing the light beam 15 to propagate between the end sections, respectively:
  • Gas sampling module 6 in fig. 2a the module may be constituted by a pipe with a gas input and output 7 capable of being positioned in the cavity and is provided with sealing rings or similar at the ends 8,9 toward the optical interface 2 and reflector 3a.
  • the module is telescopically extendable 10 so as to apply a force toward the cavity ends to push and seal the chamber toward sealing surfaces around the optical interface and the opposite end, possibly including the reflector.
  • This force may be provided by a threaded connection 10 or a spring force sealing against the cavity ends 8,9.
  • a known gas can be led through the chamber and the gas sensor may be tested.
  • the gas sampling module has a relatively small volume changes in the gas composition will be detected quickly.
  • Gas filter module 11 in fig. 2b.
  • This module may be fitted into the cavity and contains an optical filter 12, preferably an absorption or diffractive filter, to be installed in the module, the filter having known spectral properties, for example corresponding to at least part of the absorption spectrum of a gas to be measured or chosen to test or calibrate the spectral resolution and accuracy of the sensor.
  • the filter 12 may preferably be an absorption filter or possibly a diffractive filter, and may be exchangeable and be introduced through a slot 16 in the module into the light path so that different tests may be performed depending in the situation. In this case the module should be sufficiently closed to avoid gas from the surroundings or external light entering the module and disturbing the measurements.
  • the filter may be of any type suitable for obtaining the relevant attenuation in the light beam within the required wavelengths.
  • This module includes means for protecting the cavity from water, for example rain or spray from irrigation systems, fire extinguishers etc. It may also constitute mosquito nets or filters for stopping bugs or particles from entering the cavity or be a hydrophobic filter for humid environments.
  • the shield will preferably enclose a space sufficient 14 for allowing a test gas container or conductor inside the shield 13 between the optical interface 2 and the reflector 3a.
  • Alternative gas filter module 11 in fig. 2d.
  • the filter 12a is a reflective filter positioned at an angle relative to the light beam 15 transmitting the selected wavelengths corresponding to the gas to be detected through the filter 12a, while reflecting the rest of the light 15a out of the light path 15.
  • the module may be transparent of treated so as to absorb the reflected light 15a.
  • light corresponding to the gas to be detected is reflected out from the light path while other wavelengths continue through the filter. Remaining light received at the detector is compared to outgoing light. The change in light of the incoming light compared to outgoing light corresponds to the gas to be detected and thereby simulating a gas response.
  • Figure 3 illustrates the cross section of the module housing 5 with a cavity 1 with a module receiver 15 adapted to receive and hold the module with a corresponding shape.
  • the module housing is adapted to receive and also mechanically protect the modules and cavity and thus may have openings for allowing gas flowing freely though both the housing circumference and the module receiver.
  • the shape and size of the modules may vary with the implementation and in the case of the case of the gas sampling module the part of the cavity holding the module in place may be the sealing surfaces around the optical interface 2 and reflector 3a, so that the volume in the module is small, only containing the volume directly between the optical interface and reflector, and thus minimizing the response time for detecting a change in the gas composition in the module.
  • the modules may simply fit into the cavity and be held in place with suitable locking devices, but should fit sufficiently against the cavity ends to protect the optical interface and reflector. Similar may apply to the shape of the gas filter module 11 , which also should be sufficiently closed against the end surfaces 2,3 to avoid gas entering which could interfere with the calibrations and adjustments.
  • an optical measuring system including a sensor unit with a light source directing a light beam in a predetermined wavelength range through an optical interface along a predetermined light path, and a light receiver with a directional sensitivity field directed through said optical interface along said light path for receiving optical signals within the predetermined wavelength range.
  • the system also including a reflector at a predetermined distance from the optical interface reflecting the light beam from the source back to the receiver.
  • the sensor unit includes a housing part 5 defining a cavity 1 extending along the light path from the optical interface 2 to said reflector 3a, the cavity having shape adapted to receive and contain a module in said in said light path so that the light is emitted into the module and the light receiver receives light from the cavity, the cavity for containing said module extending from said optical interface.
  • the reflector 3a is preferably positioned in the housing at the end 3 of the cavity opposite from the optical interface 2, but may be positioned in said module.
  • the optical interface 2 may include one or more lenses for focusing the emitted or received light beam.
  • the cavity defined by the housing part may include sealing means between the module and the sensor unit enclosing said optical interface 2 as well as the cavity end preferably enclosing the reflector 3a.
  • the system according to the invention may include different measurements modules including a module having an optical filter to be positioned in the defined light path, where the filter is adapted to have the same absorption and/or transmission spectrum as a chosen gas, thus being adapted to test the response of the sensor unit.
  • the filter may be exchangeable and be positioned in a suitable slot in the module.
  • the system may also include a module including an enclosed sample gas corresponding to the gas to be detected, thus being adapted to test the response of the sensor unit.
  • the system may also include a module which includes a gas chamber with input and output channels for leading the gas through the chamber, the input including fluid interface for receiving the gas, where the module preferably is open in the direction of the optical interface as well as, if applicable, to the reflector at the opposite cavity end, and including an axially extendable module housing adapted to provide a sealing between the opening and around the optical interface.
  • the system may also include a module includes openings for allowing gas flow, the openings being dimension to stop water, insects and/or particles to enter into the module.

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Abstract

The present invention relates to an optical measuring system including a sensor unit with a light source directing a light beam in a predetermined wavelength range through an optical interface along a predetermined light path, and a light receiver with a directional sensitivity field directed through said optical interface along said light path for receiving optical signals within the predetermined wavelength range. The system also includes a reflector at a predetermined distance from the optical interface reflecting the light beam from the source back to the receiver. The sensor unit includes a housing part defining a cavity extending along the light path from the optical interface to said reflector, the cavity having shape adapted to receive and contain a module in said in said light path so that the light is emitted into the module and the light receiver receives light from the cavity, the cavity for containing said module extending from said optical interface.

Description

GAS DETECTOR SYSTEM
The present invention relates to a modular gas measuring and detection system, especially related to optical gas measurements.
Gas detectors of different types have been well known for a long time, for example as described in US6337741 , EP3198261 or US9678010, involving a light source transmitting a light beam through a gas and a receiver means measuring and analyzing the received light in order to detect the presence of a gas. The spectrum analysis may be performed by changing the wavelength of the source, e.g. using tunable lasers, or by analyzing the received light from a known source after having passed through the gas volume. In EP3198261 the gas volume is a closed volume with input and output for providing a gas flow through the volume.
Two types of Optical Gas detectors dominate: Point Gas Detectors and Open Path Detectors. Point Detectors measures the gas that reaches the detection point of the detector and must therefore be close to the leak point, and positioned correct relative to the wind direction. Open Path Detectors consists of one unit that is emitting light and another unit that measures the light, and these two units can be placed far from each other. These two units can detect gases passing between them. This way, large areas can be "fenced" in with a few Open Path detectors effectively monitoring for gas. Using Point Detectors to monitor such an area would in many situations demand too many detectors, but may have other advantages such as being less sensitive to other materials and disturbances entering the measured area, e.g. as is discussed in international application No. PCT/EP2020/072644.
The gas measuring system according to the present invention is primarily a point detector, but may with some modifications be used as an open path detector depending on the use. It may be used in a number of environments such as hydrocarbon production, mining, or in ships, with necessary adaptations to the gas to be detected, to facilitate testing and calibration or to the general situation at the site, e.g. protecting against rain, mosquitos, particles etc. The existing solutions are, however, not very flexible, making these adaptations. Thus it is an object of the present invention to provide a practical solution making it possible to use the same sensor unit in different environments or situations. This is obtained with a system as specified in the accompanying claims.
This way the present invention provides a modular system for providing a convenient and inexpensive solution for improving the flexibility of the optical gas detector.
The present invention will be described below with reference to the accompanying drawings illustrating the invention by way of examples.
Fig. 1 a,b illustrates the preferred embodiment of the system according to the invention.
Fig. 2a-2d illustrates different modules to be used in the present invention.
Fig. 3 illustrates the cross section of a preferred embodiment of the invention.
Figure 1 a shows a schematic illustration of the system according to the invention including a sensor unit 4, including light source, light receiver and necessary supporting circuitry for analyzing, power supply and possibly wired and/or wireless communication with external computers and network. The sensor unit 4 is per se known in the art and will not be discussed in detail here.
The sensor unit 4 includes a housing part 5 with a cavity or recess 1 for releasable containing a module A,B,C,D. In the drawing the sensor unit 4 includes an optical interface 2 on one side of the cavity 1 for directing light from the light source into the cavity and also for receiving light from the cavity 1 , the optical interface 2 may include one or more suitable windows, lenses etc. for controlling the light beam, from the light source and back into the sensor or just a defined opening.
In the preferred embodiment cavity 1 in the housing part 5 also includes a mirror or reflector 3a, preferably a retroreflector, at the opposite end 3 of the cavity 1 thus defining a volume in which the measurements may be performed, the cavity 1 having a defined length from the optical interface 2 to the opposite end 3 preferably containing the reflector 3a. The modules according to the preferred embodiment having a length corresponding to the cavity length and at least enclosing a volume defined by the light beam between the optical interface 2 and the cavity end 3.
In some cases the reflector may be positioned inside the module or, if used as an open path detector, at a different position. The advantage of having the reflector integrated in the housing is that it maintains a consistence in the measurements which removes one variable in e.g. calibrations, which could be caused by using different reflectors in different modules.
The housing part 5 may be of any shape providing mechanical protection, allowing gas in the environment pass unhindered and preferably also have sealing surfaces on or preferably around the optical interface 2 and reflector 3a or cavity end 3 so as to be able to allow a module to contain a gas between the interface and reflector without adding additional elements in the optical beam path. The shape of the cavity 1 may correspond directly to the shape of at least one of the modules or be larger to make sure future module types may be used. The important feature being that the light is allowed to pass unhindered through the optical interface 2 to or from the source and sensor and the reflector 3a. Referring to figure 1 b the preferred embodiment of the invention therefor has the opening in the housing for introducing the module B into the side of the housing part 5 so that the module is entered into the cavity between the optical interface on one end and the reflector on the other end.
The sensor unit 4 and housing 5 with reflector 3 will be capable of measuring a chosen gas in the cavity without a module mounted therein. The inventive design will, however, provide the benefits of the present invention by introducing a chosen module in the cavity, e.g. for protection, calibration or testing purposes, or for connecting the cavity to a chamber of conduit leading a gas flow through the module.
Possible modules may come from the following list as illustrated in figures 2a, 2b, 2c, 2d where the modules include end sections 8,9 for positioning over the optical interface and reflector for allowing the light beam 15 to propagate between the end sections, respectively:
• Gas sampling module 6 in fig. 2a. In this case the module may be constituted by a pipe with a gas input and output 7 capable of being positioned in the cavity and is provided with sealing rings or similar at the ends 8,9 toward the optical interface 2 and reflector 3a. Preferably the module is telescopically extendable 10 so as to apply a force toward the cavity ends to push and seal the chamber toward sealing surfaces around the optical interface and the opposite end, possibly including the reflector. This force may be provided by a threaded connection 10 or a spring force sealing against the cavity ends 8,9.
A known gas can be led through the chamber and the gas sensor may be tested. As the gas sampling module has a relatively small volume changes in the gas composition will be detected quickly.
As an alternative a closed gas sample container may be fitted into the cavity, thus not requiring any sealing or input and output, but on the other hand the characteristics of the container must be known so as not to affect the measurements. Gas filter module 11 in fig. 2b. This module may be fitted into the cavity and contains an optical filter 12, preferably an absorption or diffractive filter, to be installed in the module, the filter having known spectral properties, for example corresponding to at least part of the absorption spectrum of a gas to be measured or chosen to test or calibrate the spectral resolution and accuracy of the sensor. The filter 12 may preferably be an absorption filter or possibly a diffractive filter, and may be exchangeable and be introduced through a slot 16 in the module into the light path so that different tests may be performed depending in the situation. In this case the module should be sufficiently closed to avoid gas from the surroundings or external light entering the module and disturbing the measurements. The filter may be of any type suitable for obtaining the relevant attenuation in the light beam within the required wavelengths.
Environment shield 13 in fig. 2c. This module includes means for protecting the cavity from water, for example rain or spray from irrigation systems, fire extinguishers etc. It may also constitute mosquito nets or filters for stopping bugs or particles from entering the cavity or be a hydrophobic filter for humid environments.
The shield will preferably enclose a space sufficient 14 for allowing a test gas container or conductor inside the shield 13 between the optical interface 2 and the reflector 3a.
Alternative gas filter module 11 in fig. 2d. In this case the filter 12a is a reflective filter positioned at an angle relative to the light beam 15 transmitting the selected wavelengths corresponding to the gas to be detected through the filter 12a, while reflecting the rest of the light 15a out of the light path 15. The module may be transparent of treated so as to absorb the reflected light 15a.
Again, light corresponding to the gas to be detected is reflected out from the light path while other wavelengths continue through the filter. Remaining light received at the detector is compared to outgoing light. The change in light of the incoming light compared to outgoing light corresponds to the gas to be detected and thereby simulating a gas response.
Figure 3 illustrates the cross section of the module housing 5 with a cavity 1 with a module receiver 15 adapted to receive and hold the module with a corresponding shape. As stated above the module housing is adapted to receive and also mechanically protect the modules and cavity and thus may have openings for allowing gas flowing freely though both the housing circumference and the module receiver.
As mentioned above the shape and size of the modules may vary with the implementation and in the case of the case of the gas sampling module the part of the cavity holding the module in place may be the sealing surfaces around the optical interface 2 and reflector 3a, so that the volume in the module is small, only containing the volume directly between the optical interface and reflector, and thus minimizing the response time for detecting a change in the gas composition in the module.
In other cases, like with the environmental protecting modules 13, the modules may simply fit into the cavity and be held in place with suitable locking devices, but should fit sufficiently against the cavity ends to protect the optical interface and reflector. Similar may apply to the shape of the gas filter module 11 , which also should be sufficiently closed against the end surfaces 2,3 to avoid gas entering which could interfere with the calibrations and adjustments.
To summarize the present invention relates to an optical measuring system including a sensor unit with a light source directing a light beam in a predetermined wavelength range through an optical interface along a predetermined light path, and a light receiver with a directional sensitivity field directed through said optical interface along said light path for receiving optical signals within the predetermined wavelength range. The system also including a reflector at a predetermined distance from the optical interface reflecting the light beam from the source back to the receiver.
The sensor unit includes a housing part 5 defining a cavity 1 extending along the light path from the optical interface 2 to said reflector 3a, the cavity having shape adapted to receive and contain a module in said in said light path so that the light is emitted into the module and the light receiver receives light from the cavity, the cavity for containing said module extending from said optical interface.
The reflector 3a is preferably positioned in the housing at the end 3 of the cavity opposite from the optical interface 2, but may be positioned in said module.
The optical interface 2 may include one or more lenses for focusing the emitted or received light beam.
The cavity defined by the housing part may include sealing means between the module and the sensor unit enclosing said optical interface 2 as well as the cavity end preferably enclosing the reflector 3a.
The system according to the invention may include different measurements modules including a module having an optical filter to be positioned in the defined light path, where the filter is adapted to have the same absorption and/or transmission spectrum as a chosen gas, thus being adapted to test the response of the sensor unit. The filter may be exchangeable and be positioned in a suitable slot in the module.
The system may also include a module including an enclosed sample gas corresponding to the gas to be detected, thus being adapted to test the response of the sensor unit. The system may also include a module which includes a gas chamber with input and output channels for leading the gas through the chamber, the input including fluid interface for receiving the gas, where the module preferably is open in the direction of the optical interface as well as, if applicable, to the reflector at the opposite cavity end, and including an axially extendable module housing adapted to provide a sealing between the opening and around the optical interface. The system may also include a module includes openings for allowing gas flow, the openings being dimension to stop water, insects and/or particles to enter into the module.

Claims

Claims
1 . Modular gas detection system including a sensor unit with a light source directing a light beam in a predetermined wavelength range through an optical interface along a predetermined light path, and a light receiver with a directional sensitivity field directed through said optical interface along said light path for receiving light within the predetermined wavelength range, the system also including a reflector at a predetermined distance from the optical interface reflecting the light beam from the source back to the receiver, and the sensor unit includes a housing part defining a cavity extending along the light path from the optical interface to said reflector, wherein the cavity have a shape adapted to receive and contain a module in said in said light path so that the light is emitted into the module and the light receiver receives light from the module.
2. Measuring system according to claim 1 , wherein said reflector is positioned in the housing at the end of the cavity opposite from the optical interface.
3. Measuring system according to claim 1 , wherein said reflector is positioned in said module.
4. Measuring system according to claim 1 , wherein said optical interface includes one or more lenses for focusing the emitted or received light beam.
5. Measuring system according to claim 1 , including sealing means between the module and the sensor unit enclosing said optical interface.
6. Module for use in a system according to claim 1 , wherein the module includes an optical filter to be positioned in said light path and wherein said filter is adapted to have the same absorption or transmission spectrum as a chosen gas, thus being adapted to test the response of the sensor unit. Module according to claim 6 wherein the optical filter is exchangeable. Module for use in a system according to claim 1 , wherein the module includes a gas chamber including a sample gas corresponding to the gas to be detected, thus being adapted to test the response of the sensor unit. Module for use in a system according to claim 1 , wherein the module includes a gas chamber and input and output channels for leading a gas through the chamber, the input including fluid interface for receiving the gas. Module according to claim 9, wherein the module is open in the direction of the optical interface and including an axially extendable module housing adapted to provide a sealing between the opening and around the optical interface. Module according to claim 10, wherein the module is open in the direction of the cavity end, the end including a reflector, and adapted to provide a sealing between the opening and around the reflector. Module for use in a system according to claim 1 , wherein the cavity and the module includes openings for allowing gas flow, the openings in the modules being dimensioned to stop water, insects and/or particles to enter into the module.
PCT/EP2021/072420 2020-08-14 2021-08-11 Gas detector system WO2022034152A1 (en)

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NO20200904 2020-08-14
NO20200904A NO20200904A1 (en) 2020-08-14 2020-08-14 Gas detector system

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Citations (7)

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