CN111413281A - High-sensitivity telemetering type gas sensor - Google Patents
High-sensitivity telemetering type gas sensor Download PDFInfo
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- CN111413281A CN111413281A CN202010289370.7A CN202010289370A CN111413281A CN 111413281 A CN111413281 A CN 111413281A CN 202010289370 A CN202010289370 A CN 202010289370A CN 111413281 A CN111413281 A CN 111413281A
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- G—PHYSICS
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- 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
- G01N21/1702—Systems in which incident light is modified in accordance with the properties of the material investigated with opto-acoustic detection, e.g. for gases or analysing solids
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- 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
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- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
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- G01N2021/0118—Apparatus with remote processing
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- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/1702—Systems in which incident light is modified in accordance with the properties of the material investigated with opto-acoustic detection, e.g. for gases or analysing solids
- G01N2021/1704—Systems in which incident light is modified in accordance with the properties of the material investigated with opto-acoustic detection, e.g. for gases or analysing solids in gases
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Abstract
The invention belongs to the technical field of optical fiber sensing and trace gas detection, and discloses a high-sensitivity telemetering type gas sensor which comprises a metal shell, a buffer chamber, a resonant cavity, an integrated sensing probe, a sealing cover, a reflector and a gas hole. The sensor designed based on the T-shaped resonant photoacoustic cell and the optical fiber cantilever microphone can simultaneously realize high-sensitivity detection and long-distance remote measurement of trace gases. Because the T-shaped resonant photoacoustic cell is used as a generation place of the photoacoustic signal, high-sensitivity detection of trace gas can be realized. Because the detection light source and the excitation light source are all transmitted by the optical fiber, the long-distance remote measurement of the trace gas can be realized. But this high sensitivity remote measurement formula gas sensor simple structure, optic fibre cantilever beam microphone and T type photoacoustic cell can dismantle and be connected, and it is convenient to install. The special design of the cantilever beam diaphragm can ensure that the excitation light source passes through smoothly, and meanwhile, the high-sensitivity detection of the photoacoustic signal can be realized.
Description
Technical Field
The invention belongs to the technical field of optical fiber sensing and trace gas detection, and relates to a high-sensitivity telemetering gas sensor based on a T-shaped resonance photoacoustic cell and an optical fiber cantilever microphone.
Background
The method is mainly characterized in that gas chromatography, a semiconductor gas sensor method, an electrochemical sensor method, an absorption spectroscopy method and a photoacoustic spectroscopy method are mainly used for measuring multiple gases at the same time, the gas chromatography needs to be used together with carrier gas, the gas chromatography needs to be replaced regularly, the maintenance cost of instruments is high, the cost of the semiconductor gas sensor method and the cost of the electrochemical sensor method are low, the limit detection sensitivity respectively reaches the order of ppm (parts-per-million) and ppb (parts-per-bioclion), but the two sensors have short service life and serious cross interference between gases, the concentration measurement sensitivity of most gas molecules can be realized by adopting a proper light source and an infrared absorption spectroscopy analysis method, the measurement sensitivity of infrared absorption spectroscopy is in a proportional relation with the absorption range, the absorption spectroscopy generally needs a long absorption cell, the absorption cell is an absorption spectrum, the sensitivity of infrared absorption spectroscopy is changed into a high sensitivity spectrum of photoacoustic spectroscopy, the infrared absorption spectroscopy is changed into a high selectivity spectrum spectroscopy, the detection sensitivity of photoacoustic spectroscopy, the photoacoustic spectroscopy is changed into a high selectivity spectrum spectroscopy system based on the photoacoustic resonance of photoacoustic spectroscopy, the photoacoustic spectroscopy is changed into a photoacoustic spectroscopy, the photoacoustic spectroscopy is realized by using a photoacoustic spectroscopy, the photoacoustic spectroscopy of a photoacoustic spectroscopy, the photoacoustic spectroscopy is changed into a photoacoustic spectroscopy, the photoacoustic spectroscopy is carried out the photoacoustic spectroscopy, the photoacoustic spectroscopy is carried out by using a photoacoustic spectroscopy, the photoacoustic spectroscopy is carried out the photoacoustic spectroscopy, the photoacoustic spectroscopy is carried out the photoacoustic spectroscopy, the photoacoustic spectroscopy is carried out the photoacoustic spectroscopy, the photoacoustic spectroscopy is carried out the photoacoustic spectroscopy, the detection is carried out the photoacoustic spectroscopy is carried out the photoacoustic spectroscopy, the detection is carried out by the detection is.
At present, trace gas detection systems based on photoacoustic spectroscopy can be divided into two types according to different working models, namely resonant photoacoustic systems and non-resonant photoacoustic systems. The resonant photoacoustic cell modulates a light source by a certain eigenfrequency of the acoustic wave propagating in the photoacoustic cell, the acoustic wave forms a standing wave in the photoacoustic cell, and the photoacoustic signal realizes resonance amplification. The resonance type photoacoustic system has a large photoacoustic signal amplitude and a strong noise suppression capability, and thus has a higher detection sensitivity. In conclusion, the resonant photoacoustic spectroscopy gas sensor which can realize remote telemetry and has high sensitivity has important application value.
Disclosure of Invention
The invention aims to provide a high-sensitivity telemetering type gas sensor based on a T-shaped resonant photoacoustic cell and an optical fiber cantilever beam microphone, aims to solve the problem that the long-distance telemetering and the high-sensitivity detection of a traditional photoacoustic spectroscopy gas detection system cannot be realized simultaneously, and expands a larger space for the application of a photoacoustic spectroscopy detection technology in the field of long-distance telemetering of trace gases.
The technical scheme of the invention is as follows:
a high-sensitivity telemetering type gas sensor comprises a metal shell 1, a buffer chamber 2, a resonant cavity 3, an integrated sensing probe 4, a sealing cover 5, a reflector 6 and an air hole 7; wherein, a cylindrical buffer chamber 2 and a resonant cavity 3 structure are processed in the cylindrical metal shell 1, and the two structures form a T-shaped resonant photoacoustic cell; one side of the metal shell 1, which is close to the buffer chamber 2, is detachably connected with a cylindrical sealing cover 5; a reflector 6 is embedded in the middle of the sealing cover 5 and used for improving the reflection efficiency of the excitation light source; a plurality of air holes 7 are formed in the sealing cover 5 and used for gas exchange; one side of the metal shell 1, which is close to the resonant cavity 3, is detachably connected with the integrated sensing probe 4, and an excitation light source with the modulation frequency identical to the first-order resonance frequency of the T-shaped resonant photoacoustic cell is emitted from the middle part of the integrated sensing probe 4 to cause the periodic vibration of the gas to be detected in the resonant cavity 3, so that a resonant photoacoustic signal is generated; the position of the integrated sensing probe 4 is the antinode position of the resonant photoacoustic signal, and the photoacoustic signal is maximum; the integrated sensing probe 4 collects the resonant photoacoustic signals and obtains the concentration information of the gas to be measured through signal processing.
The integrated sensing probe 4 mainly comprises a threaded shell 8, a detection optical fiber 9 of an optical fiber F-P acoustic wave sensor, an incident optical fiber 10 of an excitation light source, an F-P cavity 11 and a cantilever beam diaphragm 12; wherein, the threaded shell 8 is detachably connected with the metal shell 1 of the high-sensitivity telemetering type gas sensor; the front end of a detection optical fiber 9 of the optical fiber F-P acoustic wave sensor is level with the side of the F-P cavity 11, which is far away from the cantilever beam diaphragm 12, deviates from the central position of the cross section of the integrated sensing probe 4 and is used for transmitting a detection light source of the optical fiber F-P acoustic wave sensor; the front end of an incident optical fiber 10 of the excitation light source is level with the cantilever beam diaphragm 12 and is positioned at the central position of the cross section of the integrated sensing probe 4, and the excitation light source is used for transmitting the photoacoustic signal.
The cantilever beam diaphragm 12 mainly comprises a stainless steel sheet 13, a small hole 14 and a cantilever beam 15; wherein, the center of the stainless steel sheet 13 is provided with a small hole 14, and the photoacoustic signal excitation light source transmitted in the incident optical fiber 10 of the excitation light source passes through the small hole 14; the position of the cantilever beam 15 and the detection optical fiber 9 of the optical fiber F-P acoustic wave sensor are on the same axis, so that a detection light source emitted from the detection optical fiber 9 of the optical fiber F-P acoustic wave sensor just irradiates to the position below the middle beam of the cantilever beam 15, and the detection sensitivity of the integrated sensing probe to the photoacoustic signal is the maximum at the moment.
The invention has the beneficial effects that: the sensor designed based on the T-shaped resonant photoacoustic cell and the optical fiber cantilever microphone can simultaneously realize high-sensitivity detection and long-distance remote measurement of trace gases. Because the T-shaped resonant photoacoustic cell is used as a generation place of the photoacoustic signal, high-sensitivity detection of trace gas can be realized. Because the detection light source and the excitation light source are all transmitted by the optical fiber, the long-distance remote measurement of the trace gas can be realized. But this high sensitivity remote measurement formula gas sensor simple structure, optic fibre cantilever beam microphone and T type photoacoustic cell can dismantle and be connected, and it is convenient to install. The special design of the cantilever beam diaphragm can ensure that the excitation light source passes through smoothly, and meanwhile, the high-sensitivity detection of the photoacoustic signal can be realized. The invention provides a new technical means for high-sensitivity remote gas telemetering in high-risk environment.
Drawings
FIG. 1 is a schematic diagram of a high sensitivity telemetric gas sensor.
FIG. 2 is a schematic diagram of an integrated sensing probe for emitting excitation light sources and detecting photoacoustic signals.
Figure 3 is a schematic view of a cantilever beam diaphragm.
In the figure: 1 a metal housing; 2 a buffer chamber; 3, a resonant cavity; 4, integrating a sensing probe; 5, sealing the cover; 6, a reflector; 7 air holes; 8, a threaded shell; 9, a detection optical fiber of the optical fiber F-P acoustic wave sensor; 10 an incident optical fiber for exciting a light source; 11F-P cavity; 12 cantilever beam diaphragm; 13 stainless steel sheet; 14 small holes; 15 cantilever beam.
Detailed Description
The following further describes a specific embodiment of the present invention with reference to the drawings and technical solutions.
The invention provides a high-sensitivity telemetering gas sensor shown in figure 1, which comprises a metal shell 1, a buffer chamber 2, a resonant cavity 3, an integrated sensing probe 4, a sealing cover 5, a reflector 6 and an air hole 7. The cylindrical buffer chamber 2 and the resonant cavity 3 both form a T-shaped resonant photoacoustic cell, and photoacoustic signals realize resonance amplification in the T-shaped resonant photoacoustic cell, so that the detection limit sensitivity of gas is improved. The sealing cover 5 is provided with a plurality of air holes 7, and a reflecting mirror 6 is embedded in the center of the sealing cover and can be detachably connected with the metal shell 1. The metal shell 1 is detachably connected with the integrated sensing probe 4 on one side close to the resonant cavity 3.
Fig. 2 shows a schematic diagram of an integrated sensing probe for emitting an excitation light source and detecting a photoacoustic signal, which includes a threaded housing 8, a detection fiber 9 of a fiber F-P acoustic wave sensor, an incident fiber 10 of the excitation light source, an F-P cavity 11 and a cantilever diaphragm 12. The front end of a detection optical fiber 9 of the optical fiber F-P acoustic wave sensor is level with the side of the F-P cavity 11 far away from the cantilever beam diaphragm 12, and deviates from the central position of the cross section of the integrated sensing probe 4. The front end of an incident optical fiber 10 of the excitation light source is level with the cantilever diaphragm 12 and is positioned at the central position of the cross section of the integrated sensing probe 4.
Figure 3 shows a cantilever beam diaphragm schematic comprising a stainless steel plate 13, an aperture 14, and a cantilever beam 15. The stainless steel sheet 13 is provided with a plurality of small holes 14 at the center. The cantilever beam 15 is on the same axis with the detection optical fiber 9 of the optical fiber F-P acoustic wave sensor.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (3)
1. A high-sensitivity telemetering type gas sensor is characterized by comprising a metal shell (1), a buffer chamber (2), a resonant cavity (3), an integrated sensing probe (4), a sealing cover (5), a reflector (6) and an air hole (7); wherein, a cylindrical buffer chamber (2) and a resonant cavity (3) structure are processed in the cylindrical metal shell (1), and the two structures form a T-shaped resonant photoacoustic cell; one side of the metal shell (1) close to the buffer chamber (2) is detachably connected with the cylindrical sealing cover (5); a reflector (6) is embedded in the middle of the sealing cover (5) and used for improving the reflection efficiency of the excitation light source; the sealing cover (5) is provided with a plurality of air holes (7) for gas exchange; one side of the metal shell (1), which is close to the resonant cavity (3), is detachably connected with the integrated sensing probe (4), and an excitation light source with the modulation frequency same as the first-order resonance frequency of the T-shaped resonant photoacoustic cell is emitted from the middle part of the integrated sensing probe (4) to cause the periodic vibration of the gas to be detected in the resonant cavity (3), so that a resonant photoacoustic signal is generated; the integrated sensing probe (4) is positioned at the position of an antinode of the resonant photoacoustic signal, and the photoacoustic signal is maximum; the integrated sensing probe (4) collects the resonant photoacoustic signals and obtains the concentration information of the gas to be measured through signal processing.
2. The high-sensitivity telemetric gas sensor according to claim 1, wherein the integrated sensing probe (4) is mainly composed of a threaded housing (8), a detection fiber (9) of a fiber F-P acoustic wave sensor, an incident fiber (10) of an excitation light source, an F-P cavity (11) and a cantilever diaphragm (12); wherein, the threaded shell (8) is detachably connected with the metal shell (1) of the high-sensitivity telemetering type gas sensor; the front end of a detection optical fiber (9) of the optical fiber F-P acoustic wave sensor is level with one side of the F-P cavity (11) far away from the cantilever beam diaphragm (12), deviates from the central position of the cross section of the integrated sensing probe (4), and is used for transmitting a detection light source of the optical fiber F-P acoustic wave sensor; the front end of an incident optical fiber (10) of the excitation light source is level with the cantilever beam diaphragm (12), and is positioned at the central position of the cross section of the integrated sensing probe (4) and used for transmitting the excitation light source of the photoacoustic signal.
3. The high sensitivity telemetric gas sensor according to claim 2, wherein the cantilever beam diaphragm (12) is mainly composed of a stainless steel sheet (13), a small hole (14) and a cantilever beam (15); wherein, the center of the stainless steel sheet (13) is provided with a small hole (14), and the photoacoustic signal excitation light source transmitted in the incident optical fiber (10) of the excitation light source passes through the small hole (14); the position of the cantilever beam (15) and the detection optical fiber (9) of the optical fiber F-P acoustic wave sensor are on the same axis, so that a detection light source emitted by the detection optical fiber (9) of the optical fiber F-P acoustic wave sensor just irradiates to the position below the middle beam of the cantilever beam (15), and the detection sensitivity of the integrated sensing probe to the photoacoustic signal is the maximum.
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| CN202010289370.7A CN111413281B (en) | 2020-04-14 | 2020-04-14 | High-sensitivity telemetering type gas sensor |
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| CN202010289370.7A CN111413281B (en) | 2020-04-14 | 2020-04-14 | High-sensitivity telemetering type gas sensor |
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| CN207850906U (en) * | 2018-03-02 | 2018-09-11 | 苏州感闻环境科技有限公司 | A kind of resonant mode photoacoustic cell for the detection of gas optoacoustic spectroscopy |
| CN109490217A (en) * | 2019-01-07 | 2019-03-19 | 大连理工大学 | A kind of multi-cavity superposing type off-resonance photoacoustic cell and gas detecting system |
| CN110346302A (en) * | 2019-07-20 | 2019-10-18 | 大连理工大学 | The resonant gas sensor of diaphragm and detection system based on poly |
| CN110763630A (en) * | 2018-07-25 | 2020-02-07 | 南京诺威尔光电系统有限公司 | Resonant photoacoustic spectroscopy detection system and method |
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2020
- 2020-04-14 CN CN202010289370.7A patent/CN111413281B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7765871B2 (en) * | 2006-07-12 | 2010-08-03 | Finesse Solutions, Llc | System and method for gas analysis using photoacoustic spectroscopy |
| US20100147051A1 (en) * | 2008-12-11 | 2010-06-17 | Honeywell International Inc. | Apparatus and method for using the speed of sound in photoacoustic gas sensor measurements |
| CN207850906U (en) * | 2018-03-02 | 2018-09-11 | 苏州感闻环境科技有限公司 | A kind of resonant mode photoacoustic cell for the detection of gas optoacoustic spectroscopy |
| CN110763630A (en) * | 2018-07-25 | 2020-02-07 | 南京诺威尔光电系统有限公司 | Resonant photoacoustic spectroscopy detection system and method |
| CN109490217A (en) * | 2019-01-07 | 2019-03-19 | 大连理工大学 | A kind of multi-cavity superposing type off-resonance photoacoustic cell and gas detecting system |
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