A portable natural gas leak detection device

Abstract

The utility model relates to natural gas leak detection technical field, concretely provides a kind of portable natural gas leak detection device, the detection device includes prefilter, for filtering impurity in gas;Detection pool;Suction pump, the prefilter, the detection pool and the suction pump are connected by tracheal structure;Laser transmitter, the laser transmitter generates preset light intensity, wavelength is 3.2 or 3.3 μm laser, the laser is incident to the detection pool inside;Light intensity detection component, the light intensity detection component is provided with first photodetector on the detection pool;Data processor, the first photodetector is electrically connected with the data processor, the data processor is based on the electrical signal of first photodetector and the laser light intensity detection methane concentration incident to the detection pool inside;The utility model has the advantages of fast detection speed, high detection precision, is suitable for the patrol inspection of methane leakage.

Description

Technical Field

[0001] This utility model relates to the field of natural gas leak detection technology, and in particular to a portable natural gas leak detection device. Background Technology

[0002] With the widespread use of natural gas in the energy sector, its safety has become an increasingly important concern. A natural gas leak not only wastes energy but can also trigger serious safety accidents such as fires and explosions, posing a significant threat to life and property.

[0003] Currently, existing natural gas leak detection methods and devices have certain limitations. Some traditional detection equipment has low accuracy and is difficult to detect minute leaks; some devices have slow detection speeds and cannot meet the needs of large-area rapid inspections; and some detection devices are greatly affected by environmental factors, such as in complex weather conditions or environments with other interfering gases, resulting in inaccurate detection results. Therefore, this application proposes a portable natural gas leak detection device. Utility Model Content

[0004] The purpose of this invention is to provide a portable natural gas leak detection device to solve the problem of low accuracy in current natural gas leak detection devices.

[0005] To achieve the above objectives, this utility model provides the following technical solution: A portable natural gas leak detection device, the detection device comprising: A pre-filter is used to filter impurities in gas; Detection pool; The air pump, the pre-filter, the detection cell and the air pump are connected by an air pipe structure. The air pump draws gas from the detection cell and discharges it, so that the external sample gas enters the detection cell after passing through the pre-filter. A laser emitter that generates a laser with a preset intensity and a wavelength of 3.2 or 3.3 μm, the laser being incident on the interior of the detection cell; A light intensity detection component, wherein a first photodetector is provided on the detection pool, and laser light incident into the detection pool irradiates the first photodetector; A data processor is provided, wherein the first photodetector is electrically connected to the data processor, and the data processor detects the methane concentration based on the electrical signal from the first photodetector and the intensity of the laser light incident on the detection cell.

[0006] Furthermore, the pre-filter has a three-stage filtration structure, and the pre-filter includes: an internally disposed... The primary filtration system is a filter screen structure used to intercept larger particles of impurities. Secondary filtration, which is used to filter out smaller impurities and moisture; The three-stage filtration system is an activated carbon filter structure used to absorb and remove residual fine particles as well as adsorb odors and some interfering gases in the gas. The air entering the pre-filter flows through the first-stage filter, the second-stage filter, and the third-stage filter in sequence.

[0007] Furthermore, the pre-filter also includes: A filter housing includes a filter mounting plate, a filter core tube, and a filter outer tube. The filter core tube is fixedly connected to the filter mounting plate and is used for primary filtration inside the filter core tube. The filter outer tube is fixedly connected to the filter mounting plate and is coaxially arranged with the filter core tube. The filter inner shell is a cylindrical shape with an opening at one end. The inner diameter of the filter inner shell is larger than the outer diameter of the filter core tube. The opening of the filter inner shell is fixed to the filter mounting plate. A filter communication hole is provided on the filter inner shell near the filter mounting plate. The secondary filter is fixed to the end of the filter core tube located inside the filter inner shell. The outer filter tube is located on the outside of the filter inner shell. The tertiary filter is filled between the outer filter tube and the filter inner shell. A filter rear cover plate is fixedly connected to the end of the filter outer tube away from the filter mounting plate. The filter rear cover plate is provided with filter air outlet holes. Multiple filter support columns are also fixed between the bottom of the filter rear cover plate and the filter inner shell.

[0008] Furthermore, the detection pool is a Heriot-Limited Pool.

[0009] Furthermore, the light intensity detection component also includes: A semi-transparent, semi-reflective mirror is located in the optical path between the laser emitter and the detection cell; The second photodetector is used to detect the intensity of the laser light emitted from the semi-transparent mirror. The laser light generated by the laser emitter is incident on the semi-transparent mirror. Half of the laser light is reflected by the semi-transparent mirror to the detection cell, and the other half of the laser light passes through the semi-transparent mirror and is incident on the second photodetector.

[0010] Furthermore, a light-shielding box is also provided on the outside of the semi-transparent mirror and the second photodetector.

[0011] Furthermore, the detection device also includes: A temperature control mechanism is used to control the ambient temperature of the laser emitter and the detection pool.

[0012] Furthermore, the detection device also includes: The outer casing contains a detection chamber, and the laser emitter and the detection pool are both installed inside the detection chamber. The temperature control mechanism blows constant-temperature air into the detection chamber.

[0013] In summary, this utility model has the following advantages compared with the prior art: The portable natural gas leak detection device disclosed in this embodiment of the invention detects and measures methane concentration based on the principle of light absorption. Compared with traditional technology, it has the advantages of fast detection speed and high detection accuracy, and is suitable for inspection of methane leaks. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the portable natural gas leak detection device disclosed in the embodiments of this utility model.

[0015] Figure 2 This is a schematic diagram of the internal structure of the portable natural gas leak detection device disclosed in an embodiment of this utility model.

[0016] Figure 3 This is a front view of the portable natural gas leak detection device disclosed in an embodiment of this utility model.

[0017] Figure 4 for Figure 3 Sectional view of AA.

[0018] Figure 5 for Figure 3 A sectional view of CC.

[0019] Figure 6 for Figure 3 A cross-sectional view of BB.

[0020] Figure 7 for Figure 4 A magnified view of a section at point I.

[0021] Figure label: 100. Housing; 110. Detection chamber; 200. Pre-filter; 210. Filter housing; 211. Filter mounting plate; 212. Filter core tube; 213. Filter outer tube; 220. Filter inner shell; 221. Filter connecting hole; 230. Filter rear cover plate; 231. Filter outlet; 240. Primary filter; 250. Secondary filter; 260. Tertiary filter; 270. Filter support column; 300. Detection tank; 310. Tank body; 320. Reflective surface; 330. Detection air inlet; 340. Detection air outlet; 4 00. Laser emitter; 500. Light intensity detection component; 510. First photodetector; 520. Semi-transparent mirror; 530. Second photodetector; 540. Light shield; 600. Data processor; 700. Intake pump; 800. Temperature control mechanism; 900. Air outlet; 910. Air outlet housing; 911. Air outlet mounting plate; 912. Air outlet core tube; 913. Air outlet outer tube; 920. Air outlet inner shell; 921. Air outlet connecting hole; 930. Air outlet rear cover plate; 931. Air outlet interface; 940. Air outlet support column. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.

[0023] Figures 1 to 7As shown in the figure, one embodiment of this utility model provides a portable natural gas leak detection device. The detection device includes a housing 100, a pre-filter 200, a detection pool 300, a laser emitter 400, a light intensity detection component 500, a data processor 600, and a suction pump 700. The pre-filter 200, detection pool 300, laser emitter 400, light intensity detection component 500, data processor 600, and suction pump 700 are all installed inside the housing 100. The pre-filter 200, the detection pool 300, and the suction pump 700 are connected by a gas pipe structure. The suction pump 700 draws gas from the detection pool 300 and discharges it. The external sample gas enters the detection cell 300 after passing through the pre-filter 200. The laser emitter 400 generates a laser with a preset intensity and wavelength of 3.2 or 3.3 μm. The laser is incident on the detection cell 300. The light intensity detection component 500 is equipped with a first photodetector 510 on the detection cell 300. The laser incident on the detection cell 300 irradiates the first photodetector 510. The first photodetector 510 is electrically connected to the data processor 600. The data processor 600 detects the methane concentration based on the electrical signal of the first photodetector 510 and the light intensity of the laser incident on the detection cell 300.

[0024] Specifically, in this embodiment, during inspection, the detection device is carried to the detection location and activated. The suction pump 700 starts, drawing gas from inside the detection pool 300, creating negative pressure within the pool. Outside air enters the pool 300 through the pre-filter 200. After the suction pump 700 has run for a preset time, the filtered outside air fills the detection pool 300. The laser emitter 400 is then activated, and the laser light generated by the emitter 400 is incident on the detection pool 300. Since methane has a wavelength of 3.2 nm... The laser has strong absorption at 3.3 μm, while the absorption of other gases is weak to the point of being negligible. After passing through the gas, the laser is incident on the first photodetector 510. The first photodetector 510 detects the intensity of the laser after absorption by the gas. When the laser irradiates the first photodetector 510, the first photodetector 510 generates an electrical signal. The data processor 600 detects the intensity of the electrical signal of the first photodetector 510 to identify the intensity of the laser irradiating the first photodetector 510. The concentration of methane is calculated by comparing the intensity of the laser light incident into the detection cell 300 with the intensity of the absorbed laser light.

[0025] The portable natural gas leak detection device disclosed in this embodiment of the invention detects and measures methane concentration based on the principle of light absorption. Compared with traditional technology, it has the advantages of fast detection speed and high detection accuracy, and is suitable for inspection of methane leaks.

[0026] Specifically, in this embodiment, the housing 100 is a magnesium alloy explosion-proof cavity. The housing 100 is composed of multiple magnesium alloy plates fixedly connected by screws to form a box-shaped structure. The pre-filter 200 is fixedly connected to the housing 100 by screws. The air inlet of the pre-filter 200 is located on the outside of the housing 100, and the air outlet of the suction pump 700 is located on the side of the housing 100 away from the pre-filter 200, so that the air inlet of the pre-filter 200 and the air outlet of the suction pump 700 are not in the same direction.

[0027] like Figures 4 to 7 As shown in the preferred embodiment, the pre-filter 200 has a three-stage filtration structure, comprising a primary filter 240, a secondary filter 250, and a tertiary filter 260. The primary filter 240 is a filter mesh structure used to intercept larger particles of impurities, such as dust and sand. For example, the primary filter 240 may be a sponge block or non-woven fabric. The secondary filter 250 is used to filter smaller impurities and moisture. For example, the secondary filter 250 may be a hydrophobic membrane or a PEFR hydrophobic membrane with a pore size ≤ 5 μm. The tertiary filter 260 is an activated carbon filter structure used to absorb and remove residual fine particles, as well as adsorb odors and some interfering gases in the gas, ensuring the purity of the gas sample entering the laser detection module.

[0028] Preferably, in this embodiment, the pre-filter 200 further includes a filter housing 210, a filter inner shell 220, and a filter rear cover plate 230. The primary filter 240, secondary filter 250, and tertiary filter 260 are installed inside the filter housing 210, the filter inner shell 220, and the filter rear cover plate 230. The filter housing 210 includes a filter mounting plate 211, a filter core tube 212, and a filter outer tube 213. The filter core tube 212 is fixedly connected to the filter mounting plate 211 and penetrates the filter mounting plate 211. The primary filter 240 is fixed by an interference fit. The filter inner shell 220 is a cylindrical shape with an opening at one end, and its inner diameter is larger than the outer diameter of the filter core tube 212. The opening of the filter inner shell 220 is fixed to the filter mounting plate 211, so that the filter inner shell 220 is fastened to the outside of the filter core tube 212. A filter communication hole 221 is provided near the filter mounting plate 211 in the filter inner shell 220 to connect the inner and outer sides of the filter inner shell 220. The secondary filter 250 is fixed to the end of the filter core tube 212 located inside the filter inner shell 220. The filter outer tube... 213 is a cylindrical tube with openings at both ends. The outer filter tube 213 and the filter mounting plate 211 are fixedly connected. The outer filter tube 213 and the filter core tube 212 are coaxially arranged. The outer filter tube 213 is located outside the inner filter shell 220. The three-stage filter 260 is filled between the outer filter tube 213 and the inner filter shell 220. The rear filter cover plate 230 is fixedly connected to the end of the outer filter tube 213 away from the filter mounting plate 211. The rear filter cover plate 230 is provided with a filter outlet hole 231. The rear filter cover plate 230 and the bottom of the inner filter shell 220 are connected. Multiple filter support columns 270 are also fixed, creating an airflow gap between the filter cover plate 230 and the filter inner shell 220. Air entering from the primary filter 240 passes through the primary filter 240, filter core tube 212, and secondary filter 250 before entering the channel between the filter inner shell 220 and filter core tube 212, then entering the tertiary filter 260, and finally entering the detection pool 300 through the filter outlet 231. The arrangement of the filter housing 210, filter inner shell 220, and filter housing 210 forms a labyrinthine channel at the air inlet, effectively improving explosion-proof performance.

[0029] Preferably, the detection cell 300 is a Heriot-Limiter cell. Laser light incident into the detection cell 300 is reflected multiple times before reaching the first photodetector 510. The detection cell 300 includes a cell body 310, a reflective surface 320, a detection air inlet 330, and a detection air outlet 340. The cell body 310 is a cylindrical body with openings at both ends. The reflective surface 320 is fixedly connected to both ends of the cell body 310. One side of the reflective surface 320 on the inner side of the cell body 310 is concave. The reflective surface 320 is used for... The reflected laser is incident inside the detection cell 300 and, after multiple reflections by the reflective surface 320, is incident on the first photodetector 510. The reflective surface 320 is designed to increase the optical path and extend the interaction time between the laser and methane. The detection inlet 330 and the detection outlet 340 are located on different reflective surfaces 320. The reflective surfaces 320 are positioned to avoid the laser reflection point on the reflective surface 320. The first photodetector 510 is embedded in the reflective surface 320.

[0030] Preferably, the laser entrance hole on the reflective surface 320 is sealed by a calcium fluoride lens.

[0031] The laser emitter 400 is a tunable semiconductor laser, and the laser emitter 400 is connected to the detection cell 300 via an optical fiber.

[0032] As a preferred embodiment of this example, Figure 6 As shown, the light intensity detection component 500 further includes a semi-transparent mirror 520 and a second photodetector 530. The semi-transparent mirror 520 is located in the optical path between the laser emitter 400 and the detection cell 300. The second photodetector 530 is used to detect the intensity of the laser light emitted from the semi-transparent mirror 520. The laser light generated by the laser emitter 400 is incident on the semi-transparent mirror 520. Half of the laser light is reflected by the semi-transparent mirror 520 to the detection cell 300, and the other half of the laser light passes through the semi-transparent mirror 520. The laser light is incident on the second photodetector 530, enabling the second photodetector 530 to detect the intensity of the laser light entering the detection cell 300. For some lasers, the intensity of the laser light is affected by voltage and temperature. When the intensity of the laser light fluctuates, it can easily affect the measurement accuracy. The semi-transparent and semi-reflective mirror 520 can divide the laser into two identical parts. One part is incident on the detection cell 300, and the other part is incident on the second photodetector 530 and detected by the second photodetector 530.

[0033] Preferably, a light-shielding box 540 is also provided outside the semi-transparent mirror 520 and the second photodetector 530. The laser emitter 400 is connected to the light-shielding box 540 through an optical fiber, and the light-shielding box 540 is connected to the detection cell 300 through an optical fiber.

[0034] The data processor 600 is existing technology. For example, the data processor 600 includes a data acquisition card, a lock-in amplifier, and a computer. The electrical signals generated by the semi-transparent mirror 520 and the second photodetector 530 are transmitted to the data acquisition card. The data acquisition card transmits the signals to the lock-in amplifier. The lock-in amplifier amplifies the electrical signals and transmits them to the computer. The computer calculates the gas concentration of methane based on the Beer-Lambert law.

[0035] As stated, the computer calculates the methane concentration using formula (1): C = k·R·f(T, P); Formula (1) Wherein, C is the methane gas concentration, k is the proportionality coefficient obtained by calibration with standard concentration gas, R is the ratio of the laser light intensity incident into the detection cell 300 to the laser light intensity detected by the first photodetector 510, and f(T, P) is the temperature and pressure compensation formula. Both k and f(T, P) are obtained by laboratory experiments with standard concentration gas.

[0036] It should be noted that when the data processor 600 acquires the laser light intensity received by the first photodetector 510, it also acquires the pressure and temperature of the gas in the detection pool 300. Specifically, the data processor 600 acquires the gas temperature and pressure in the detection pool 300 through the temperature sensor and pressure sensor inside the detection pool 300.

[0037] The suction pump 700 is existing technology.

[0038] In a preferred embodiment of this invention, the detection device further includes a temperature control mechanism 800 for controlling the ambient temperature of the laser emitter 400 and the detection pool 300. In this embodiment, a detection chamber 110 is provided inside the housing 100, and both the laser emitter 400 and the detection pool 300 are installed inside the detection chamber 110. The temperature control mechanism 800 is a prior art technology, such as having an air flow structure (fan), a heating structure (electric heating element), and a cooling structure (compressor-type refrigerator or semiconductor refrigeration element) inside. The air flow structure draws in outside air and blows it sequentially onto the heating structure and the cooling structure. The air blown out from the cooling mechanism is blown into the detection chamber 110. A temperature sensor is provided inside the detection chamber 110. The data processor 600 controls the operation of the heating structure and the cooling structure by detecting the temperature inside the detection chamber 110, so that the air blown into the detection chamber 110 is maintained at a preset temperature.

[0039] As a preferred embodiment of this example, Figure 5 As shown, the detection device further includes: An air outlet 900 is provided, and the air outlet end of the suction pump 700 is connected to the air outlet 900. The air outlet 900 is fixedly connected to the housing 100. The air outlet 900 includes an air outlet housing 910, an air outlet inner housing 920, and an air outlet rear cover plate 930. The air outlet housing 910 includes an air outlet mounting plate 911, an air outlet core tube 912, and an air outlet outer tube 913. The air outlet core tube 912 is fixedly connected to the air outlet housing 100. On the mounting plate 911, the air outlet inner shell 920 is a cylindrical shape with an opening at one end. The inner diameter of the air outlet inner shell 920 is larger than the outer diameter of the air outlet core tube 912. The opening of the air outlet inner shell 920 is fixed to the air outlet mounting plate 911, so that the air outlet inner shell 920 is fastened to the outside of the air outlet core tube 912. The air outlet inner shell 920 is provided with an air outlet connecting hole 921 near the air outlet mounting plate 911 to connect the air outlet inner shell 920. On the inner and outer sides of the shell 920, the secondary filter 250 is fixed to one end of the air outlet core tube 912 located inside the air outlet inner shell 920. The air outlet outer tube 913 is a cylindrical tube with openings at both ends. The air outlet outer tube 913 is fixedly connected to the air outlet mounting plate 911. The air outlet outer tube 913 and the air outlet core tube 912 are coaxially arranged. The air outlet outer tube 913 is located on the outside of the air outlet inner shell 920. The air outlet rear cover plate 930 is fixedly connected to the end of the air outlet outer tube 913 away from the air outlet mounting plate 911. The air outlet rear cover plate 930 is provided with an air outlet interface 931. The air outlet interface 931 is connected to the air outlet end of the air intake pump 700. Multiple air outlet support columns 940 are also fixed between the air outlet rear cover plate 930 and the bottom of the air outlet inner shell 920, so that there is a gap for air flow between the air outlet rear cover plate 930 and the air outlet inner shell 920.

[0040] The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular forms “a,” “the,” and “the” used in this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0041] It should be understood that although the terms first, second, third, etc., may be used in this invention to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this invention, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0042] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A portable natural gas leak detection device, characterized in that, The detection device includes: A pre-filter is used to filter impurities in gas; Detection pool; The air pump, the pre-filter, the detection cell and the air pump are connected by an air pipe structure. The air pump draws gas from the detection cell and discharges it, so that the external sample gas enters the detection cell after passing through the pre-filter. A laser emitter that generates a laser with a preset intensity and a wavelength of 3.2 or 3.3 μm, the laser being incident on the interior of the detection cell; A light intensity detection component, wherein a first photodetector is provided on the detection pool, and laser light incident into the detection pool irradiates the first photodetector; A data processor, wherein the first photodetector is electrically connected to the data processor, and the data processor detects the methane concentration based on the electrical signal of the first photodetector and the intensity of the laser light incident into the detection cell; The pre-filter has a three-stage filtration structure, comprising a primary filter, a secondary filter, and a tertiary filter. The primary filter is a filter screen structure used to intercept larger particles of impurities. The secondary filter is used to filter smaller impurities and moisture. The tertiary filter is an activated carbon filter structure used to absorb and remove residual fine particles and adsorb odors and some interfering gases in the gas. The air entering the pre-filter flows through the primary filter, the secondary filter, and the tertiary filter in sequence.

2. The portable natural gas leak detection device according to claim 1, characterized in that, The pre-filter also includes: A filter housing includes a filter mounting plate, a filter core tube, and a filter outer tube. The filter core tube is fixedly connected to the filter mounting plate and is used for primary filtration inside the filter core tube. The filter outer tube is fixedly connected to the filter mounting plate and is coaxially arranged with the filter core tube. The filter inner shell is a cylindrical shape with an opening at one end. The inner diameter of the filter inner shell is larger than the outer diameter of the filter core tube. The opening of the filter inner shell is fixed to the filter mounting plate. A filter communication hole is provided on the filter inner shell near the filter mounting plate. The secondary filter is fixed to the end of the filter core tube located inside the filter inner shell. The outer filter tube is located on the outside of the filter inner shell. The tertiary filter is filled between the outer filter tube and the filter inner shell. A filter rear cover plate is fixedly connected to the end of the filter outer tube away from the filter mounting plate. The filter rear cover plate is provided with filter air outlet holes. Multiple filter support columns are also fixed between the bottom of the filter rear cover plate and the filter inner shell.

3. The portable natural gas leak detection device according to claim 1, characterized in that, The detection pool is a Heriot-Lewis pool.

4. The portable natural gas leak detection device according to claim 1, characterized in that, The light intensity detection component also includes: A semi-transparent, semi-reflective mirror is located in the optical path between the laser emitter and the detection cell; The second photodetector is used to detect the intensity of the laser light emitted from the semi-transparent mirror. The laser light generated by the laser emitter is incident on the semi-transparent mirror. Half of the laser light is reflected by the semi-transparent mirror to the detection cell, and the other half of the laser light passes through the semi-transparent mirror and is incident on the second photodetector.

5. The portable natural gas leak detection device according to claim 4, characterized in that, A light-shielding box is also provided on the outside of the semi-transparent mirror and the second photodetector.

6. The portable natural gas leak detection device according to any one of claims 1-5, characterized in that, The detection device further includes: A temperature control mechanism is used to control the ambient temperature of the laser emitter and the detection pool.

7. The portable natural gas leak detection device according to claim 6, characterized in that, The detection device further includes: The outer casing contains a detection chamber, and the laser emitter and the detection pool are both installed inside the detection chamber. The temperature control mechanism blows constant-temperature air into the detection chamber.

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