In-situ real-time non-intrusive acetylene content monitoring gas relay and device

Abstract

The invention discloses an in-situ real-time non-intrusive acetylene content monitoring gas relay and device in the technical field of transformers of power transmission and transformation equipment, two inspection windows are symmetrically arranged on the gas relay along the flowing direction of oil flow, each inspection window adopts a circular three-layer composite structure, and each inspection window adopts a three-layer composite structure. The middle layer is a light-transmitting magnetic fluid cavity filled with magnetic fluid, a Halbach permanent magnet array ring is bonded outside the inspection window, an electromagnetic coil is arranged on the outer side of the ring, and the device comprises a light source unit, a photoacoustic detection unit and a magnetic fluid control device. The problem that acetylene gas cannot be detected in situ in real time in the prior art is solved by additionally arranging a light beam analyzer and a smudginess sensor, and the beneficial effects of improving the monitoring accuracy and real-time performance and enhancing the fault early warning capability are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of power transmission and transformation equipment transformers, and specifically to an in-situ real-time non-invasive acetylene content monitoring gas relay and device. Background Art

[0002] Oil-immersed transformers use transformer oil as an insulating medium and a cooling medium. When internal faults occur in the transformer, such as overheating, insulation damage, or partial discharge, the transformer oil will decompose and generate a series of characteristic gases. The composition and concentration of these gases are closely related to the type and severity of the internal faults in the transformer. Therefore, real-time monitoring of the changes in the composition and concentration of characteristic gases is of great significance for ensuring the safe operation of oil-immersed transformers. The gas relay is an important part of the non-electrical protection of oil-immersed transformers. Among them, the light gas protection of the gas relay has the ability to quickly detect and respond in the early stage of internal discharge. However, when the transformer is poorly sealed or the oil level drops, non-fault gases such as air may enter the gas relay, resulting in false alarms. Currently, gas chromatography is commonly used for characteristic gas analysis to judge the correctness of early fault alarms. The detection period of this method is on the hour level, while the time interval from the generation of fault characteristic gases to a transformer deflagration accident may be as short as a few minutes, making it difficult to meet the real-time requirements of deflagration warning. In addition, gas chromatography relies on manual on-site sampling, which not only increases the response delay but also brings significant safety hazards. There are also solutions that use photoacoustic spectroscopy gas detection methods to detect gases, but additional gas sampling is required through photoacoustic cells, etc., and in-situ real-time detection cannot be achieved. Summary of the Invention

[0003] Aiming at the deficiencies of the prior art, the present invention provides an in-situ real-time non-invasive acetylene content monitoring gas relay and device to solve the problem that the prior art cannot detect acetylene gas in-situ and in real-time.

[0004] To achieve the above objectives, the present invention is realized through the following technical solutions: An in-situ real-time non-invasive acetylene content monitoring gas relay includes gas signal contacts, oil flow rate signal contacts, and inspection windows. There are two inspection windows, which are symmetrically arranged along the oil flow direction. Each inspection window adopts a circular three-layer composite structure. The inner and outer layers of the three-layer composite structure are both solid transparent materials, and the middle layer is a light-transmitting ferrofluid cavity. A Halbach permanent magnet array ring is coaxially bonded to the outside of each inspection window. An electromagnetic coil is arranged outside the permanent magnet array ring. The ferrofluid cavity is sealed with ferrofluid, and the electromagnetic coil is provided with an interface for external connection.

[0005] Preferably, the solid transparent material is made of quartz glass, the ferrofluid is silicone oil filled with 20 vol% carboxylated Fe3O4 nanoparticles, and the nanoparticles are surface-treated with sodium laurate.

[0006] Based on the same inventive concept, the present application also discloses an in-situ real-time non-invasive acetylene content monitoring device for in-situ real-time non-invasive acetylene content monitoring of a gas relay, including a light source unit, a photoacoustic detection unit, and a ferrofluid control device. The light source unit is used to emit an infrared beam through the permanent magnet array ring of the aforementioned in-situ real-time non-invasive acetylene content monitoring gas relay and through the inspection window to the acetylene gas accumulated above the oil level in the gas relay. The photoacoustic detection unit is used to capture the acoustic signal generated by the acetylene gas through a sensor closely attached to the inspection window and then calculate the concentration of acetylene gas in the gas relay in real time. The ferrofluid control device includes a controller, and the controller is connected to the interface externally connected to the electromagnetic coil of the aforementioned in-situ real-time non-invasive acetylene content monitoring gas relay. The controller is used to stabilize the light spot of the beam emitted by the light source unit and strip the contaminated oil film on the inner side of the inspection window by controlling the current output to the coil.

[0007] Preferably, the light source unit includes a drive circuit, a broadband light source, and a filter device. The drive circuit is electrically connected to the broadband light source and controls the broadband power source to emit light. The filter device is arranged on the optical path between the light-emitting port of the broadband light source and the solid transparent material on the outer layer of the inspection window of the gas relay.

[0008] Preferably, the photoacoustic detection unit includes an acoustic wave sensor and a signal processing unit. The acoustic wave sensor is closely attached to the solid transparent material on the outer layer of the inspection window and is used to capture the acoustic signal generated by the acetylene gas and convert it into an electrical signal. The signal processing unit is used to process the electrical signal generated by the sensor unit to obtain the concentration of the target gas. The signal processing unit includes a lock-in amplifier and a host computer. The lock-in amplifier is electrically connected to the acoustic wave sensor and the host computer respectively. The lock-in amplifier is used to perform lock-in amplification processing on the electrical signal generated by the acoustic wave sensor. The host computer is used to analyze the electrical signal lock-in amplified by the lock-in amplifier to obtain the concentration of acetylene gas in the gas relay.

[0009] Preferably, the acoustic wave sensor uses a silver film fiber F-P acoustic wave sensor. The silver film fiber F-P acoustic wave sensor includes a housing, a silver film, a ceramic ferrule, and a single-mode optical fiber. The ceramic ferrule is cemented to the middle single-mode optical fiber and is arranged in the cavity of the housing. The rear end face of the ceramic ferrule is flat, and the front end face is provided with a symmetric inclination angle that shrinks forward. A silver film is arranged at the front part of the cavity.

[0010] Preferably, the inclination angle is 8°, the diameter of the silver film is 6 mm, the thickness is 0.6 μm, and the length of the Fabry-Perot cavity is 1500 μm.

[0011] Preferably, a beam analyzer is further included. The light incident port of the beam analyzer is arranged on the side of the gas relay opposite to the light source unit and is aligned with the light beam emitted by the light source unit. The data output end of the beam analyzer is electrically connected to the controller, and the beam analyzer is used to detect the spot diameter.

[0012] Preferably, a dirt sensor is further included. The dirt sensor is arranged in the incident point area of the incident inspection window of the light source unit above the oil fluid. The data output end of the dirt sensor is electrically connected to the controller, and the dirt sensor is used to detect the oil pollution state of the inner surface of the solid transparent material on the inner side of the inspection window.

[0013] Preferably, the dirt sensor uses a transmittance sensor.

[0014] Compared with the prior art, the beneficial effects of this solution are as follows: By improving the inspection window of the gas relay, the gas relay has the ability to cooperate with a suitable device to achieve in-situ real-time non-invasive monitoring of acetylene content, without the need for an additional photoacoustic cell. The in-situ real-time non-invasive acetylene content monitoring device disclosed in this application, which is combined with the gas relay, adopts the combination of a light source unit and a photoacoustic detection unit. All detection components are located outside the gas relay. Compared with the traditional gas chromatography method, the response delay is greatly reduced, real-time monitoring is realized, and the accuracy and safety of monitoring are further improved. Therefore, the concentration of acetylene gas in the gas relay can be accurately monitored. By determining the central wavelength of the filtering device, the photoacoustic signal intensity is increased, and the cross-interference of other gases is reduced. Using a fiber optic acoustic wave sensor instead of an ordinary acoustic-electric conversion device reduces the device size, improves the sound receiving sensitivity, and is not affected by electromagnetic interference. By adding additional components such as a magneto-fluid control device, a beam analyzer, and a dirt sensor, the light spot is stabilized, and the transparency of the inspection window is maintained, achieving the beneficial effects of improving the monitoring accuracy, real-time performance, and enhancing the fault warning ability. Description of the Drawings

[0015] Figure 1 It is a schematic diagram of the connection layout in the vertical oil flow direction of an embodiment of the connection between the gas relay and the monitoring device of this solution; Figure 2 It is a schematic diagram of the central cross-section of an embodiment of a silver film fiber optic F-P acoustic wave sensor; Figure 3 It is a schematic diagram of the parameters of the filter of an embodiment of the filtering device; Figure 4 It is the absorption spectrogram of other gases and the acetylene gas to be monitored near the wavenumber to be selected in the absorption spectrogram of acetylene in transformer oil; Among them, 1 - gas relay, 111 - fused silica, 112 - magnetorheological fluid chamber, 21 - Halbach permanent magnet array ring, 22 - coil, 23 - sealing ring, 31 - drive circuit, 32 - broadband light source, 33 - filter device, 41 - acoustic wave sensor, 411 - housing, 412 - silver film, 413 - ceramic ferrule, 414 - single - mode optical fiber, 42 - lock - in amplifier, 43 - host computer, 5 - beam analyzer, 6 - controller, 7 - transmittance sensor. Specific embodiments

[0016] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0017] In an embodiment of a gas relay 1 for in - situ real - time non - invasive acetylene content monitoring, it includes gas signal contacts, oil flow rate signal contacts, and inspection windows. There are two inspection windows, which are symmetrically arranged along the oil flow direction. Each inspection window adopts a circular three - layer composite structure. The inner and outer layers of the three - layer composite structure are both solid transparent materials, and the middle layer is a light - transmissive magnetorheological fluid chamber 112. A Halbach permanent magnet array ring 21 is coaxially bonded to the outside of each inspection window. An electromagnetic coil 22 is arranged outside the permanent magnet array ring 21. The magnetorheological fluid chamber 112 is sealed with magnetorheological fluid, and the electromagnetic coil 22 has an interface reserved for external connection. The three - layer composite structure is conducive to realizing the synergistic effect of light - magnet - force.

[0018] In this embodiment, the magnetorheological fluid is prepared by chemical precipitation method to obtain Fe3O4 nanoparticles, and then sodium laurate is used to treat the particles on the surface to make their surfaces charged, preventing the nanoparticles from precipitating in the base liquid. Silicone oil with a viscosity of 5000 cP and a refractive index of 1.40 is selected as the dispersion medium, and the concentration of the magnetorheological fluid is 20 vol%. In this embodiment, the solid transparent material is fused silica 111. The outer layer uses high - transmittance fused silica 111 with a light transmittance > 99.7% and a thickness of 5 mm, and the inner layer also uses 5 - mm fused silica 111. There is a 0.5 - mm - thick magnetorheological fluid chamber 112 between the two layers of fused silica 111. The edge of the magnetorheological fluid chamber 112 is sealed with a PDMS sealing ring 23 with an oil - corrosion resistance grade of ASTM D471 standard and an expansion rate < 3% in 72 hours. The sealing ring 23 forms a molecular - level bond with the glass interface through vacuum hot - pressing process. The particle size distribution of the silicone - based magnetorheological fluid of carboxylated Fe3O4 nanoparticles is 10 - 20 nm. The fused silica 111, magnetorheological fluid, etc. in the embodiment can be replaced by other suitable materials, such as high - transmittance PMMA, and other magnetorheological fluids with Fe2O3, Ni, and Co, etc. as nanoparticles.

[0019] In this embodiment, the Halbach permanent magnet array ring 21 and the electromagnetic coil 22 are arranged in the form of concentric rings outside the outer layer of quartz glass 111. The inner edge of the permanent magnet array ring 21 is 10 mm away from the outer edge of the outer layer of quartz glass 111, forming an annular regulation area. The Halbach permanent magnet array ring 21 uses neodymium iron boron with N52 grade and remanence of 1.45 T to provide a basic magnetic field. A copper flat coil 22 is superimposed outside the permanent magnet array ring 21. The copper wire with a wire diameter of 0.5 mm is used, with 200 turns per unit. A superimposed magnetic field is generated by adjusting the current, and finally an adjustable magnetic field gradient of 0.2 - 1 T / m is formed. In the conditions of 15 MPa oil pressure and temperature change from -40 °C to 120 °C, the deviation of magnetic field uniformity is < ±5%, and the fluctuation of light transmittance is < 1.5%. By cooperating with the controller 6 of the in-situ real-time non-invasive acetylene content monitoring device, the spot diameter can be kept stable by adjusting the current of the coil 22, so as to obtain a stable signal.

[0020] Based on the same inventive concept, this application discloses an in-situ real-time non-invasive acetylene content monitoring device for use in conjunction with the in-situ real-time non-invasive acetylene content monitoring gas relay 1, including a light source unit, a photoacoustic detection unit, and a magnetohydrodynamic control device. The light source unit is used to emit an infrared beam through the inside of the permanent magnet array ring 21 of the aforementioned in-situ real-time non-invasive acetylene content monitoring gas relay and through the inspection window to the acetylene gas accumulated above the oil liquid level in the gas relay. In this embodiment, the light source unit includes a drive circuit 31, a broadband light source 32, and a filtering device 33. The drive circuit 31 is electrically connected to the broadband light source 32 and controls the broadband power supply to emit light. The drive circuit 31 outputs a square wave current signal with a frequency of 50 Hz, a high level of 2.4 V, a low level of 0 V, and a duty cycle of 50%. The broadband light source 32 uses a blackbody radiation infrared broad-spectrum light source with a wavelength range of 4000 nm to 11000 nm. The filtering device 33 is arranged on the optical path between the light emitting port of the broadband light source 32 and the solid transparent material on the outer layer of the inspection window of the gas relay 1. In this embodiment, the filtering device 33 uses a filter. The parameters of the filter are shown as Figure 3 , where CWL in the figure is the center wavelength of the filter, and T peak is the maximum transmittance of the filter, and HW is the full width at half maximum. The selection of the filter parameters is based on the condition that the photoacoustic signal generated by acetylene gas is the largest and the interference of other gases is the smallest. As shown in Figure 4, A is the infrared absorption spectral peak of acetylene near 3050 nm, and B is the infrared absorption peak of other gas components that cause cross-interference in the detection of acetylene. In this embodiment, the center wavelength of the filter is preferably 3050 nm, and the full width at half maximum is preferably 100 nm, which can greatly reduce the interference of other characteristic gases. The drive circuit 31 modulates the intensity of the incident light, then passes it through the filter and enters the gas accumulated above the oil level through one inspection window of the gas relay 1. The spectral passband of the filter covers the characteristic absorption peak of acetylene gas in the mid-infrared band. The light of a specific wavelength is selectively absorbed by acetylene gas, and the gas generates periodic expansion, thereby generating an acoustic signal.

[0021] The photoacoustic detection unit is used to calculate the concentration of acetylene gas in the gas relay in real time by capturing the acoustic signal generated by acetylene gas through a sensor closely attached to the inspection window from the outside. In this embodiment, the photoacoustic detection unit includes an acoustic wave sensor 41 and a signal processing unit. The acoustic wave sensor 41 is attached to the outer solid transparent material of the inspection window and is used to capture the acoustic signal generated by acetylene gas and convert it into an electrical signal. The signal processing unit is used to process the electrical signal generated by the sensor unit to obtain the concentration of the target gas. The signal processing unit includes a lock-in amplifier 42 and a host computer 43. The lock-in amplifier 42 is electrically connected to the acoustic wave sensor 41 and the host computer 43 respectively. The lock-in amplifier 42 is used to amplify, filter, lock-in, etc. the electrical signal generated by the acoustic wave sensor 41, and convert the captured weak acoustic signal into a DC signal reflecting the amplitude of the acoustic signal frequency component corresponding to the modulation frequency. The amplitude of this signal is the photoacoustic signal intensity. The host computer 43 is used to analyze the electrical signal lock-in amplified by the lock-in amplifier 42 to obtain the concentration of acetylene gas in the gas relay. The concentration is calculated according to the clear linear relationship between the photoacoustic signal intensity and the acetylene gas concentration. The clear linear relationship between the photoacoustic signal intensity and the acetylene gas concentration can be calibrated through a pre-calibration process. A commercially available standard concentration acetylene gas can be used to calibrate the photoacoustic signal intensity of this band to establish the correlation between the measured value and the gas concentration.

[0022] To achieve a better sound collection effect, the acoustic wave sensor 41 uses a silver film optical fiber F-P acoustic wave sensor. The silver film optical fiber F-P acoustic wave sensor includes a housing 411, a silver film 412, a ceramic ferrule 413, and a single-mode optical fiber 414. The ceramic ferrule 413 is cemented to the middle single-mode optical fiber 414 and disposed in the cavity of the housing 411. The rear end face of the ceramic ferrule 413 is flat, and the front end face is provided with a symmetric taper angle that tapers forward. A silver film 412 is provided at the front part of the cavity. In this embodiment, the taper angle is 8°, the diameter of the silver film 412 is 6 mm, the thickness is 0.6 μm, and the distance from the front cone vertex of the ceramic ferrule 413 to the silver film 412 is 1500 μm. Using an optical fiber acoustic wave sensor instead of a traditional capacitive microphone has the advantages of small size, high sensitivity, and immunity to electromagnetic interference. The metal silver film has good compactness and is easy to form a film. At the same time, silver has a small Young's modulus. Using metal silver as the sensitive diaphragm of the fiber optic F-P acoustic wave sensor can obtain higher sensitivity. The acoustic wave sensor 41 is arranged as close as possible to the gas aggregation area, that is, the position close to the incident optical axis. To avoid affecting the operation of other components, in this embodiment, the vertical distance between the acoustic wave sensor and the incident optical axis is greater than or equal to 3 mm.

[0023] The magnetic fluid control device includes a controller 6. The controller 6 is connected to the interface externally connected to the electromagnetic coil 22 of the aforementioned in-situ real-time non-invasive acetylene content monitoring gas relay 1. The controller 6 includes a current controller for stabilizing the light spot of the light beam emitted by the light source unit and stripping the oil film contaminated on the inner side of the inspection window by controlling the current output to the coil 22. The stable light spot realizes the dynamic adjustment of the refractive index of the magnetic fluid by controlling the magnetic field to drive the Fe3O4 nanoparticles to form a density gradient, compensating for the laser beam divergence angle. The process of stripping the oil film can be carried out by timed stripping or by stripping when the inner side of the inspection window is detected to be dirty. The controller 6 activates the rotating magnetic field mode by starting the magnetic field eddy current flushing program: the coil array is activated in sequence to generate a rotating magnetic field with a rotation speed of 50 rpm. The nanoparticles of the magnetic fluid form a microscale turbulence with a Reynolds number Re≈200 under the drive of the Lorentz force, thereby stripping more than 90% of the oil film.

[0024] To better stabilize the light spot, the device further includes a beam analyzer 5. The light inlet of the beam analyzer 5 is arranged on the opposite side of the gas relay 1 relative to the light source unit and is aligned with the light beam emitted by the light source unit. The data output end of the beam analyzer 5 is electrically connected to the controller 6. During the process of monitoring the acetylene gas content of the gas relay 1, the light spot diameter in the beam geometric parameters is obtained through the beam analyzer 5. After the controller 6 detects the fluctuation of the light spot diameter, it adjusts the coil current to keep the light spot diameter stable, thereby obtaining a stable signal.

[0025] When the device is used to strip oil stains when detecting dirt on the inner side of the inspection window, the device further includes a dirt sensor. The dirt sensor is arranged in the incident point area of the light source unit above the oil liquid that enters the inspection window, as close to the incident point as possible, so as to judge the dirt condition of the incident point area on the inner side of the inspection window as accurately as possible. The data output end of the dirt sensor is electrically connected to the controller 6. The dirt sensor is used to detect the oil stain pollution state of the inner surface of the solid transparent material on the inner side of the inspection window. In this embodiment, the dirt sensor uses a transmittance sensor 7. The body of the transmittance sensor 7 is placed on the incident light side of the gas relay 1, and is separately placed on the other side of the gas relay 1 to simultaneously detect the dirt condition on the inner sides of the two quartz glasses 111. When the transmittance is less than a set threshold, such as 70%, the magnetic field eddy current flushing program is started to strip the oil stains.

[0026] In addition to using the transmittance sensor 7, the dirt sensor can also use other devices such as a camera to judge the dirt condition on the inner side of the inner layer quartz glass 111 by taking pictures.

[0027] The measurement percentage error of the acetylene gas concentration in the solution of this application does not exceed 10%. This solution can not only be used for acetylene gas detection, but also for other gas detections when using different filter devices 33 and the corresponding photoacoustic signal intensity correlation tables.

[0028] In the description of this specification, the schematic diagrams in the drawings highlight the main features and key parts of the figures, and appropriately simplify or omit details. Therefore, they do not represent the proportional and dimensional relationships in reality. The descriptions with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0029] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. An in-situ real-time non-invasive acetylene content monitoring gas relay, comprising a gas signal contact, an oil flow rate signal contact, and an inspection window, characterized in that: There are two inspection windows, which are symmetrically arranged along the oil flow direction. Each inspection window adopts a circular three-layer composite structure. The inner and outer layers of the three-layer composite structure are both solid transparent materials, and the middle layer is a light-transmitting magnetorheological fluid chamber (112). A Halbach permanent magnet array ring (21) is coaxially bonded to the outside of each inspection window. An electromagnetic coil (22) is arranged outside the permanent magnet array ring (21). The magnetorheological fluid chamber (112) is sealed with magnetorheological fluid, and the electromagnetic coil (22) is reserved with an interface for external connection.

2. The in-situ real-time non-invasive acetylene content monitoring gas relay according to claim 1, characterized in that: The solid transparent material is made of quartz glass. The magnetorheological fluid is silicone oil filled with 20 vol% carboxylated Fe3O4 nanoparticles, and the nanoparticles are surface-treated with sodium laurate.

3. An in-situ real-time non-invasive acetylene content monitoring device for in-situ real-time non-invasive acetylene content monitoring of a gas relay (1), characterized in that: It includes a light source unit, a photoacoustic detection unit, and a magnetorheological fluid control device. The light source unit is used to emit an infrared beam to pass through the permanent magnet array ring (21) of the in-situ real-time non-invasive acetylene content monitoring gas relay according to one of claims 1 to 2 and then pass through the inspection window to the acetylene gas accumulated above the oil surface in the gas relay. The photoacoustic detection unit is used to capture the acoustic signal generated by the acetylene gas through a sensor closely attached to the inspection window and then calculate the concentration of acetylene gas in the gas relay in real time. The magnetorheological fluid control device includes a controller (6). The controller (6) is connected to the interface for external connection of the electromagnetic coil (22) of the in-situ real-time non-invasive acetylene content monitoring gas relay according to one of claims 1 to 2. The controller (6) is used to stabilize the light spot of the beam emitted by the light source unit and strip the contaminated oil film on the inner side of the inspection window by controlling the current output to the coil (22).

4. The in-situ real-time non-invasive acetylene content monitoring device according to claim 3, characterized in that: The light source unit includes a drive circuit (31), a broadband light source (32), and a filter device (33). The drive circuit (31) is electrically connected to the broadband light source (32) and controls the broadband power source to emit light. The filter device (33) is arranged on the optical path between the light-emitting port of the broadband light source (32) and the solid transparent material of the outer layer of the inspection window of the gas relay (1).

5. The in-situ real-time non-invasive acetylene content monitoring device according to claim 4, characterized in that: The photoacoustic detection unit includes an acoustic wave sensor (41) and a signal processing unit. The acoustic wave sensor (41) is closely attached to the solid transparent material of the outer layer of the inspection window and is used to capture the acoustic signal generated by the acetylene gas and convert it into an electrical signal. The signal processing unit is used to process the electrical signal generated by the sensor unit to obtain the target gas concentration. The signal processing unit includes a lock-in amplifier (42) and a host computer (43). The lock-in amplifier (42) is electrically connected to the acoustic wave sensor (41) and the host computer (43) respectively. The lock-in amplifier (42) is used to perform lock-in amplification processing on the electrical signal generated by the acoustic wave sensor (41). The host computer (43) is used to analyze the electrical signal lock-in amplified by the lock-in amplifier (42) to obtain the concentration of acetylene gas in the gas relay.

6. The in-situ real-time non-invasive acetylene content monitoring device according to claim 5, wherein: The acoustic wave sensor (41) uses a silver film fiber optic F-P acoustic wave sensor, which includes a housing (411), a silver film (412), a ceramic ferrule (413), and a single-mode optical fiber (414). The ceramic ferrule (413) is cemented to the middle single-mode optical fiber (414) and is disposed in the cavity of the housing (411). The rear end face of the ceramic ferrule (413) is flat, and the front end face is provided with a symmetrically tapered angle that narrows forward. The silver film (412) is disposed at the front part of the cavity.

7. The in-situ real-time non-invasive acetylene content monitoring device according to claim 6, characterized in that: The tapered angle is 8°, the diameter of the silver film (412) is 6 mm, the thickness is 0.6 μm, and the distance from the front cone vertex of the ceramic ferrule (413) to the silver film (412) is 1500 μm.

8. The in-situ real-time non-invasive acetylene content monitoring device according to claim 1, characterized in that: It further includes a beam analyzer (5). The light inlet of the beam analyzer (5) is arranged on the opposite side of the gas relay (1) relative to the light source unit and is aligned with the beam emitted by the light source unit. The data output end of the beam analyzer (5) is electrically connected to the controller (6). The beam analyzer (5) is used to detect the spot diameter.

9. The in-situ real-time non-invasive acetylene content monitoring device according to claim 5, characterized in that: It further includes a dirt sensor. The dirt sensor is disposed in the incident point area of the incident inspection window of the light source unit above the oil fluid. The data output end of the dirt sensor is electrically connected to the controller (6). The dirt sensor is used to detect the oil pollution state of the inner surface of the solid transparent material on the inner side of the inspection window.

10. The in-situ real-time non-invasive acetylene content monitoring device according to claim 5, characterized in that: The dirt sensor uses a transmittance sensor (7).

Images