A pump-out laser gas sensor

Abstract

The utility model relates to gas sensor technical field, and disclose a kind of pump extraction formula laser gas sensor, including lower shell, the top of lower shell is clamped with upper cover, the inside assembly of lower shell has gas chamber, and one end of lower shell is welded with detector board, and detector is welded on detector board, and one end of detector is bonded on the first end wall of gas chamber, the other end of lower shell is welded with laser board, and laser is welded on laser board, and one end of laser is bonded on the second end wall of gas chamber, and the above of gas chamber is provided with sensor mainboard, and the both ends of two sensor mainboards are respectively welded with detector board, laser board.The utility model uses pump extraction formula active air intake, overcome the shortcoming that diffusion formula sensor waits gas slow diffusion, can quickly extract the gas of distal end leak point to measuring gas chamber, greatly shorten the response time of system, and it is crucial for the industrial safety scene needing fast alarm.

Description

Technical Field

[0001] This utility model relates to the field of gas sensor technology, and more specifically, to a pump-extracting laser gas sensor. Background Technology

[0002] Preventing gas explosions is a key aspect of safe production. Developing highly reliable and stable flammable and explosive gas sensors is of great significance for safe production. Currently, gas sensors used in the market are divided into catalytic, semiconductor, and infrared types. Catalytic sensors have high sensitivity, fast response time, are less affected by humidity and temperature, and are easy to use. However, they have a small range, are susceptible to poisoning from high concentrations of gas and sulfides, and suffer from zero drift and sensitivity drift, requiring frequent calibration. Semiconductor sensors are small in size, less susceptible to poisoning, and have a long lifespan, but have poor selectivity, especially affected by water vapor, resulting in poor accuracy and near saturation at higher concentrations. Infrared sensors have high accuracy, good selectivity, are less susceptible to poisoning and aging from harmful gases, have fast response speed, and good stability. However, infrared gas sensors have disadvantages such as requiring periodic calibration and being susceptible to cross-interference from other gases.

[0003] Laser gas sensors based on tunable semiconductor laser absorption spectroscopy (TSL) technology offer advantages such as real-time measurement, high accuracy, good selectivity, and no need for frequent calibration, making them ideal for gas leak detection and alarm applications. Tunable semiconductor laser absorption spectroscopy utilizes the wavelength tuning characteristics of semiconductor lasers and the selective absorption of laser light by the target gas to detect gas concentration. The principle is that a tunable semiconductor laser emits laser light of a specific wavelength under the modulation of a driving current. With the modulation of a periodic injected current, the wavelength changes periodically. Wavelength scanning allows the laser output center wavelength to be aligned with the absorption spectrum of the target gas. The concentration of the target gas is then deduced from the spectral intensity signal obtained after gas absorption.

[0004] Most gas leak detection sensor modules on the market currently use a diffusion method for gas collection. They are typically screwed onto the alarm or built into the alarm device and installed in some industrial sites. This diffusion method has a slow response speed and is inconvenient to disassemble, install, and maintain. For some places that require a fast response, local measurement locations cannot meet the requirements. Gas sensor modules that require gas extraction using a pump to meet the needs of a fast response are mostly not based on laser detection principles and do not have the advantages of laser sensors. Moreover, the sensor installation structure and gas circuit connection are more complex. Utility Model Content

[0005] To overcome the shortcomings of existing technologies, this utility model provides a pump-extraction laser gas sensor, which solves the problems of slow response speed and inconvenient disassembly and maintenance of existing diffusion-type gas collection methods.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a pump-extraction type laser gas sensor, comprising a lower housing, a top cover snapped onto the top of the lower housing, a gas chamber assembled on the inner side of the lower housing, a detector plate welded to one end of the lower housing, a detector welded to the detector plate, one end of the detector being adhered to the first end wall of the gas chamber, a laser plate welded to the other end of the lower housing, a laser welded to the laser plate, one end of the laser being adhered to the second end wall of the gas chamber, and a sensor main board disposed above the gas chamber, with the two ends of the two sensor main boards respectively welded to the detector plate and the laser plate.

[0007] Preferably, an air inlet pipe is provided at one end of the bottom of the air chamber, and an air outlet is provided at the other end of the bottom of the air chamber.

[0008] Preferably, the outer wall of the air intake pipe is provided with a sealing groove, and a sealing ring is fitted inside the sealing groove.

[0009] Preferably, the bottom of the lower housing is provided with a mounting groove that matches the air intake pipe, and a sealing gasket is fitted at the connection point between the mounting groove and the air intake pipe.

[0010] Preferably, the sensor motherboard is provided with a socket for communication and power-on.

[0011] Preferably, the sensor motherboard integrates signal processing, communication interface and laser driving circuit, and the detector and laser are electrically connected to the sensor motherboard.

[0012] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0013] 1. This utility model adopts a pump-extraction type active air intake, which overcomes the shortcomings of diffusion type sensors that wait for gas to diffuse slowly. It can quickly extract gas from remote leak points to the measuring gas chamber, greatly shortening the system response time, which is crucial for industrial safety scenarios that require rapid alarm.

[0014] 2. This utility model, through its unique structural design, arranges the air intake pipe and the circuit socket in the same direction (bottom). During installation, simply align the module with the air connector and circuit plug on the mounting base, and press it once to simultaneously complete the air sealing connection and circuit connection, achieving true "one-click" quick disassembly and assembly. This simplifies the installation process and facilitates daily maintenance, calibration, or replacement.

[0015] 3. By highly integrating the laser, detector, gas chamber, and mainboard into a modular housing, the structure is very compact and small in size, saving installation space; through the multiple sealing design of sealing rings and gaskets, a high degree of airtightness is ensured between the gas chamber and the outside world, as well as between the module and the mounting base, which not only prevents leakage of the gas to be measured, but also avoids the intrusion of external environmental gases or dust, ensuring the accuracy and long-term stability of the measurement.

[0016] 4. Based on TDLAS technology, the laser wavelength scans only the characteristic absorption lines of the gas molecules to be measured, with excellent selectivity and is basically unaffected by cross-interference from other background gases. The optical measurement principle is non-contact and does not consume components. It does not have the "poisoning" failure problem of catalytic combustion sensors, has a longer lifespan, and does not require frequent calibration, thus reducing the cost of later maintenance. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of a pump-extraction laser gas sensor according to the present invention.

[0018] Figure 2 This is a schematic diagram of the disassembly structure of a pump-extracting laser gas sensor according to the present invention.

[0019] Figure 3 This is a diagram showing the airflow path of the air chamber in this utility model.

[0020] Figure 4 This is a schematic diagram of the optical path of this utility model.

[0021] In the diagram: 1. Lower outer shell; 2. Sealing gasket; 3. Sealing ring; 4. Detector; 5. Detector board; 6. Air chamber; 61. First end wall; 62. Second end wall; 63. Air inlet pipe; 64. Air outlet; 65. Sealing groove; 7. Laser; 8. Laser board; 9. Sensor main board; 91. Socket; 10. Top cover. 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. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] like Figures 1 to 4As shown, this utility model provides a pump-extraction type laser gas sensor, including a lower housing 1, with a top cover 10 snapped onto the top of the lower housing 1. A gas chamber 6 is assembled inside the lower housing 1. A detector plate 5 is welded to one end of the lower housing 1, and a detector 4 is welded to the detector plate 5. One end of the detector 4 is adhered to the first end wall 61 of the gas chamber 6. A laser plate 8 is welded to the other end of the lower housing 1, and a laser 7 is welded to the laser plate 8. One end of the laser 7 is adhered to the second end wall 62 of the gas chamber 6. A sensor main board 9 is arranged above the gas chamber 6, and the two ends of the two sensor main boards 9 are respectively welded to the detector plate 5 and the laser plate 8. An air inlet pipe 63 is opened at one end of the bottom of the gas chamber 6, and an air outlet 64 is opened at the other end of the bottom of the gas chamber 6. A sealing groove 65 is opened on the outer wall of the air inlet pipe 63, and a sealing ring 3 is assembled inside the sealing groove 65.

[0024] After the external air pump (not shown in the figure, connected through the mounting slot at the bottom of the lower housing 1) is started, it generates negative pressure, drawing the gas in the environment to be tested into the gas chamber 6 through the air inlet pipe 63. The gas forms a stable flow path in the gas chamber 6, and after fully filling the entire optical cavity, it is finally discharged through the air outlet 64. This active pump extraction method replaces the traditional passive diffusion, greatly accelerating the speed of gas sampling and replacement.

[0025] Furthermore, the bottom of the lower outer casing 1 is provided with a mounting groove that matches the air inlet pipe 63, and a sealing gasket 2 is fitted at the connection point between the mounting groove and the air inlet pipe 63. Through the multiple sealing design of the sealing ring 3 and the sealing gasket 2, a high degree of airtightness is ensured between the air chamber 6 and the outside environment, as well as between the lower outer casing 1 and the mounting base. This prevents leakage of the gas to be measured and avoids the intrusion of external environmental gases or dust, thus ensuring the accuracy and long-term stability of the measurement.

[0026] Furthermore, the sensor motherboard 9 is equipped with a socket 91 for communication and power-on.

[0027] Furthermore, the sensor motherboard 9 integrates signal processing, communication interfaces, and laser driving circuits. The detector 4 and laser 7 are both electrically connected to the sensor motherboard 9.

[0028] Workflow: Under the modulation of the laser drive circuit integrated on the sensor motherboard 9, the laser 7 emits a near-infrared laser with a wavelength precisely aligned with a specific absorption line of the gas molecules to be tested. The laser beam passes through the gas chamber 6, and the gas to be tested drawn into the gas chamber 6 will selectively absorb the laser, resulting in a decrease in laser intensity. The higher the concentration of the gas to be tested, the more the laser is absorbed, and the more significant the light intensity attenuation.

[0029] After penetrating the gas, the laser beam reaches the detector 4 at the other end of the gas chamber 6. The detector 4 converts the received light signal into an electrical signal proportional to its intensity. The weak electrical signal generated by the detector 4 is first preliminarily processed and amplified by the detector board 5, and then transmitted to the sensor main board 9. The signal processing circuit (usually a microprocessor or a dedicated digital signal processing chip) on the sensor main board 9 uses harmonic detection or direct absorption algorithms to accurately deduce the concentration value of the gas to be tested by analyzing the degree of laser intensity attenuation. The calculated concentration data is output in real time to the host computer or alarm system through the communication interface (such as RS485, 4-20mA or digital bus) on the sensor main board 9 via the socket 91. The timing control, laser modulation and data communication of the entire process are all coordinated by the sensor main board 9.

[0030] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0031] 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 pump-extraction type laser gas sensor, comprising a lower housing (1), wherein a top cover (10) is snapped onto the top of the lower housing (1), characterized in that: An air chamber (6) is assembled on the inner side of the lower outer shell (1). A detector plate (5) is welded to one end of the lower outer shell (1). A detector (4) is welded to the detector plate (5). One end of the detector (4) is attached to the first end wall (61) of the air chamber (6). A laser plate (8) is welded to the other end of the lower outer shell (1). A laser (7) is welded to the laser plate (8). One end of the laser (7) is attached to the second end wall (62) of the air chamber (6). A sensor main board (9) is arranged above the air chamber (6). The two ends of the two sensor main boards (9) are welded to the detector plate (5) and the laser plate (8) respectively.

2. The pump-driven laser gas sensor according to claim 1, characterized in that: An air inlet pipe (63) is provided at one end of the bottom of the air chamber (6), and an air outlet (64) is provided at the other end of the bottom of the air chamber (6).

3. The pump-driven laser gas sensor according to claim 2, characterized in that: The outer wall of the air intake pipe (63) is provided with a sealing groove (65), and a sealing ring (3) is fitted inside the sealing groove (65).

4. The pump-driven laser gas sensor according to claim 2, characterized in that: The bottom of the lower outer shell (1) is provided with an assembly groove that matches the air intake pipe (63), and a sealing gasket (2) is fitted at the connection point between the assembly groove and the air intake pipe (63).

5. A pump-driven laser gas sensor according to claim 1, characterized in that: The sensor motherboard (9) is equipped with a socket (91) for communication and power-on.

6. The pump-driven laser gas sensor according to claim 1, characterized in that: The sensor motherboard (9) integrates signal processing, communication interface and laser driving circuit. The detector (4) and laser (7) are electrically connected to the sensor motherboard (9).

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