CN220323119U

CN220323119U - Methane ethane detector based on TDLAS principle

Info

Publication number: CN220323119U
Application number: CN202321286801.XU
Authority: CN
Inventors: 李亮亮; 李庆坤; 周锐; 李英杰
Original assignee: Wuhan Energy Technology Engineering Co ltd
Current assignee: Wuhan Energy Technology Engineering Co ltd
Priority date: 2023-05-25
Filing date: 2023-05-25
Publication date: 2024-01-09
Anticipated expiration: 2033-05-25

Abstract

The utility model relates to the technical field of gas detection, in particular to a methane-ethane detector based on a TDLAS principle, which comprises an upper cover and a lower box which are connected with each other, wherein a circuit board is arranged in the upper cover, an optical path pool and an air pump connected with the optical path pool are arranged in the lower box, a beam combiner is also arranged in the lower box, a methane laser and an ethane laser are arranged on the circuit board, and a light beam emitted by the methane laser and a light beam emitted by the ethane laser enter the optical path pool after being coupled by the beam combiner; and a photoelectric detector is arranged on the optical path cell and is electrically connected with the circuit board. The methane-ethane detector based on the TDLAS principle provided by the utility model can be used for instantaneously and simultaneously measuring the content of methane and ethane, has the advantages of high precision, high sensitivity and high response speed, can be used for rapidly distinguishing natural gas from methane according to the detected content of methane and ethane, can be used for rapidly identifying natural gas leakage, and provides a favorable technical support for gas pipeline inspection.

Description

Methane ethane detector based on TDLAS principle

Technical Field

The utility model relates to the technical field of gas detection, in particular to a methane-ethane detector based on a TDLAS principle.

Background

Along with the acceleration of urban construction in China, the types and lengths of underground pipelines are rapidly increased, when gas workers check leakage sources, biogas interference is often caused, incorrect excavation is possibly caused, a large amount of manpower and material resources are wasted, and the problem of industry puzzling first-line operators is solved. The main components of the natural gas and the biogas are methane, the natural gas contains more ethane than the biogas, and other gas species are not found in nature to contain ethane, so that the ethane can be used as characteristic gas and used as characteristic index for judging the natural gas, and the natural gas and the biogas are distinguished by detecting the ethane. The ethane identification instrument based on the traditional chromatographic principle can analyze according to the diffusion speed of ethane molecules, and can output curve graph results only in a few minutes.

The tunable semiconductor laser absorption spectroscopy (Tunable Diode Laser Absorption Spectroscopy, TDLAS for short) is an optical detection technique for detecting gas molecules by taking a tunable semiconductor laser (DFB) as an active detection light source and utilizing the physical phenomenon that gas molecules absorb the characteristics of light with specific wavelengths. The TDLAS technology fully utilizes the advantages of tunable semiconductor laser, good coherence, narrow bandwidth, good single mode property, small volume and the like, so that the technology has the advantages of high spectral resolution, high sensitivity, short response time and the like when being used for gas detection. The existing detector based on the TDLAS principle can only detect methane or ethane singly, can not detect methane and ethane at the same time, and can not distinguish natural gas and methane rapidly.

Disclosure of Invention

The utility model aims to provide a methane-ethane detector based on the TDLAS principle, which can detect the content of methane and ethane simultaneously and distinguish natural gas from methane, can rapidly identify natural gas leakage and has the advantages of high precision, high sensitivity and high response speed.

In order to achieve the above purpose, the technical scheme of the utility model is a methane-ethane detector based on the TDLAS principle, which comprises an upper cover and a lower box which are connected with each other, wherein a circuit board is arranged in the upper cover, an optical path pool and an air pump connected with the optical path pool are arranged in the lower box, a beam combiner is also arranged in the lower box, a methane laser and an ethane laser are arranged on the circuit board, and a light beam emitted by the methane laser and a light beam emitted by the ethane laser enter the optical path pool after being coupled by the beam combiner; and a photoelectric detector is arranged on the optical path cell and is electrically connected with the circuit board.

Further, a processing module, a filter circuit, an amplifying circuit and an AD conversion circuit are further arranged on the circuit board.

Further, a radiator is further arranged in the lower box and fixed on the top surface of the optical path cell, two bosses are arranged on the radiator, and the lower end of the methane laser and the lower end of the ethane laser are respectively fixed on the two bosses.

Further, a liquid crystal circuit board is mounted on the upper cover, and the liquid crystal circuit board is connected with the circuit board through a flat cable.

Further, a film key is further arranged on the top surface of the upper cover, and the film key is connected with the circuit board through a flat cable.

Further, two ends of the lower box are respectively provided with an air inlet joint and an air outlet joint, the optical path cell is provided with an air inlet and an air outlet, the air inlet is connected with the air inlet joint through an air pump, and the air outlet is connected with the air outlet joint.

Still further, the air inlet connector is connected with a filter cover, and a filter membrane is arranged between the air inlet connector and the filter cover.

Still further, sealing rings are provided between the air inlet connector and the lower case, between the air outlet connector and the lower case, and between the air outlet connector and the filter cover.

Further, a battery pack is arranged in the lower box and is connected with the circuit board; and a heat-conducting silica gel sheet is arranged on the bottom surface of the lower box at a position corresponding to the battery pack.

Further, the optical path length of the optical path cell is 10 meters.

Compared with the prior art, the utility model has the beneficial effects that:

(1) The methane-ethane detector based on the TDLAS principle can instantaneously and simultaneously measure the content of methane and ethane, has the advantages of high precision, high sensitivity and high response speed, can rapidly distinguish natural gas from methane according to the detected content of methane and ethane, and rapidly identify natural gas leakage, and is more rapid and visual than the traditional method;

(2) The methane-ethane detector based on the TDLAS principle provided by the utility model has the advantages of long service life, strong anti-interference capability and convenience in use.

Drawings

In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a perspective view of a methane-ethane detector based on the TDLAS principle according to an embodiment of the present utility model;

fig. 2 is an exploded view of a methane-ethane detector based on the TDLAS principle according to an embodiment of the present utility model;

in the figure: 1. an upper cover; 2. a lower box; 3. an air pump; 4. an optical path cell; 5. a filter cover; 6. an air outlet joint; 7. a connecting screw; 8. a liquid crystal circuit board; 9. a laser fixing screw; 10. a methane laser; 11. a circuit board fixing screw; 12. a circuit board; 13. a radiator fixing screw; 14. a heat sink; 15. a battery pack; 16. a seal ring; 17. a nut; 18. a seal ring; 19. an air inlet joint; 20. a seal ring; 21. a film key; 22. a thermally conductive silicone sheet; 23. an ethane laser; 24. a boss; 25. and (5) hanging the ear.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

In the description of the present utility model, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate describing the present utility model and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model.

As shown in fig. 1-2, the embodiment provides a methane-ethane detector based on the TDLAS principle, which comprises an upper cover 1 and a lower box 2 which are connected with each other, wherein a circuit board 12 is arranged in the upper cover 1, an optical path pool 4 and an air pump 3 connected with the optical path pool 4 are arranged in the lower box 2, a beam combiner is also arranged in the lower box 2, a methane laser 10 and an ethane laser 23 are arranged on the circuit board 12, and a light beam emitted by the methane laser 10 and a light beam emitted by the ethane laser 23 enter the optical path pool 4 after being coupled by the beam combiner; the optical path cell 4 is provided with a photodetector, and the photodetector is electrically connected to the wiring board 12. In this embodiment, the light beam emitted by the methane laser 10 and the light beam emitted by the ethane laser 23 are coupled into one beam by the beam combiner and then enter the optical path pool 4, the light beam is received by the photoelectric detector and converted into an electric signal after being reflected for multiple times in the optical path pool 4, the electric signal is processed to obtain the methane and ethane content, and the detector of this embodiment can instantaneously and simultaneously measure the methane and ethane content.

As a further modification, a processing module, a filter circuit, an amplifying circuit, and an AD conversion circuit are also provided on the wiring board 12. The photoelectric detector converts the reflected laser signal into an electric signal, and then extracts a harmonic signal through the filter circuit and the amplifying circuit, and then transmits the harmonic signal to the processing module through the AD converting circuit for data processing and concentration calculation, in this embodiment, the processing module is a single-chip microcomputer, the chip type STM32F407VET6, the filter circuit, the amplifying circuit and the AD converting circuit are all in the prior art, and a person skilled in the art can select a suitable circuit to connect on the basis of the scheme, so that the description is omitted here.

As a further improvement, the lower case 2 is further provided therein with a radiator 14, the radiator 14 is fixed on the top surface of the optical path cell 4 by a radiator fixing screw 13, two bosses 24 are provided on the radiator 14, the lower end of the methane laser 10 and the lower end of the ethane laser 23 are respectively fixed on the two bosses 24 by a laser fixing screw 9, and the laser and the radiator 14 are ensured to be fully connected so as to perform better heat dissipation on the laser. The optical path cell 4 of the present embodiment is fixed in the lower case 2 by a heat sink and a screw, ensuring the stability of the optical path cell 4.

As a further improvement, a liquid crystal circuit board 8 is mounted on the upper cover 1, and the liquid crystal circuit board 8 is connected with a circuit board 12 through a flat cable. Specifically, the upper cover 1 is provided with a mounting window and a mounting stud, the liquid crystal circuit board 8 is fixed in the mounting window through the mounting stud, and the display surface of the liquid crystal circuit board 8 faces outwards, so that the methane concentration and ethane concentration data calculated by the processing module can be displayed.

As a further improvement, a film button 21 is further provided on the top surface of the upper cover 1, and the film button 21 is connected with the circuit board 12 through a flat cable.

As a further improvement scheme, two ends of the lower box 2 are respectively provided with an air inlet joint 19 and an air outlet joint 6, the optical path pool 4 is provided with an air inlet and an air outlet, the air inlet of the optical path pool 4 is connected with the air inlet joint 19 through the air pump 3, and the air outlet of the optical path pool 4 is connected with the air outlet joint 6.

As a further improvement scheme, the air inlet connector 19 is connected with the filter cover 5, a filter membrane is arranged between the air inlet connector 19 and the filter cover 5, and impurities in the gas sucked into the instrument can be filtered through the filter membrane, so that the detection accuracy is ensured.

As a further development, the air inlet connector 19 and the air outlet connector 6 are respectively fixed with the side wall of the lower box 2 through nuts 17, and optimally, a sealing ring 18 is arranged between the air inlet connector 19 and the lower box 2, a sealing ring 16 is arranged between the air outlet connector 6 and the lower box 2, and a sealing ring 20 is arranged between the air outlet connector 6 and the filter cover 5, so that the sealing performance is ensured.

As a further improvement, a battery pack 15 is arranged in the lower case 2, the battery pack 15 is connected with the circuit board 12, and the circuit board 12 is powered by the battery pack 15. Specifically, the battery pack 15 is disposed on one side of the optical path pool 4, the beam combiner may be fixed on the battery pack 15 and located below the circuit board 12, the light emitting directions of the methane laser 10 and the ethane laser 23 face the beam combiner, the light beam emitted by the methane laser 10 and the light beam emitted by the ethane laser 23 enter the beam combiner to be coupled into a path of combined light, and the combined light is injected into the optical path pool 4, and after multiple reflections, the light signals are received by the photoelectric detector and converted into electrical signals. Further, the bottom surface of the lower box 2 is provided with a heat conducting silica gel piece 22, and the heat conducting silica gel piece 22 can be specifically arranged under the battery pack 15, so that heat emitted by the battery pack 15 can be timely conducted out, and the influence on optical devices is avoided.

As a further improvement, a nameplate is also stuck on the bottom surface of the lower box 2.

As a further improvement scheme, four corner portions of the upper cover 1 and the lower box 2 are provided with screw holes, the middle parts of two sides of the length direction of the upper cover 1 and the lower box 2 are provided with screw holes, the screw holes on the upper cover 1 and the lower box 2 are in one-to-one correspondence, and the upper cover 1 and the lower box 2 can be detachably fixed together through screwing the connecting screws 7 into the screw holes corresponding to the upper cover and the lower box.

As a further improvement, one side of the lower case 2 is also provided with a hanging lug 25, and the hanging lug 25 is connected with a rope or other connecting pieces, so that the detector can be conveniently carried.

As a further improvement scheme, the optical path length of the optical path cell 4 in the embodiment is 10 meters, the reflection times of the light beam in the optical path cell 4 is 3 times of the reflection times in the optical path cell 4 in the detector for detecting only single methane content, the sensitivity is higher, the detection limit is lower, and the detection result is more accurate.

Under the action of the air pump 3, the methane-ethane detector of the embodiment sucks air into the optical path pool 4 through the air inlet connector 19, the air pump 3 and the air inlet of the optical path pool 4, and then discharges the air through the air outlet connector 6 of the optical path pool 4 to form a complete air path circulation. The laser of the methane laser 10 and the laser of the ethane laser 23 are emitted and then are combined into a beam through a beam combiner and then are irradiated into the optical path pool 4, the combined beam is reflected in the optical path pool 4 for multiple times, then the photoelectric detector fixed on the optical path pool 4 receives optical signals and converts the optical signals into electric signals, harmonic signals are extracted through a filter circuit and an amplifying circuit, the harmonic signals are transmitted to a processing module through filtering and AD conversion for data processing and concentration calculation, and finally the data processing and concentration calculation are displayed through the liquid crystal circuit board 8, so that the methane-ethane detector is a methane-ethane detector with high precision, high sensitivity and high response speed, can quickly identify natural gas leakage, and provides favorable technical support for gas pipeline inspection.

The foregoing description of the preferred embodiments of the utility model is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the utility model.

Claims

1. The utility model provides a methane ethane detector based on TDLAS principle, includes interconnect upper cover and lower box, be provided with the circuit board in the upper cover, be provided with in the lower box optical path pond and with the air pump that optical path pond is connected, its characterized in that: a beam combiner is further arranged in the lower box, a methane laser and an ethane laser are arranged on the circuit board, and the light beams emitted by the methane laser and the light beams emitted by the ethane laser enter the optical path cell after being coupled by the beam combiner; and a photoelectric detector is arranged on the optical path cell and is electrically connected with the circuit board.

2. The TDLAS based methane ethane detector of claim 1, wherein: the circuit board is also provided with a processing module, a filter circuit, an amplifying circuit and an AD conversion circuit.

3. The TDLAS based methane ethane detector of claim 1, wherein: and a radiator is further arranged in the lower box and is fixed on the top surface of the optical path cell, two bosses are arranged on the radiator, and the lower end of the methane laser and the lower end of the ethane laser are respectively fixed on the two bosses.

4. The TDLAS based methane ethane detector of claim 1, wherein: the upper cover is provided with a liquid crystal circuit board, and the liquid crystal circuit board is connected with the circuit board through a flat cable.

5. The methane-ethane detector based on the TDLAS principle according to claim 4, wherein: the top surface of the upper cover is also provided with a film key, and the film key is connected with the circuit board through a flat cable.

6. The TDLAS based methane ethane detector of claim 1, wherein: the two ends of the lower box are respectively provided with an air inlet joint and an air outlet joint, the optical path cell is provided with an air inlet and an air outlet, the air inlet is connected with the air inlet joint through an air pump, and the air outlet is connected with the air outlet joint.

7. The TDLAS based methane ethane detector of claim 6, wherein: the air inlet connector is connected with a filter cover, and a filter membrane is arranged between the air inlet connector and the filter cover.

8. The TDLAS based methane ethane detector of claim 7, wherein: sealing rings are arranged between the air inlet connector and the lower box, between the air outlet connector and the lower box and between the air outlet connector and the filter cover.

9. The TDLAS based methane ethane detector of claim 1, wherein: a battery pack is arranged in the lower box and connected with the circuit board; and a heat-conducting silica gel sheet is arranged on the bottom surface of the lower box at a position corresponding to the battery pack.

10. The TDLAS based methane ethane detector of claim 9, wherein: the optical path length of the optical path pool is 10 meters.