Miniature high-precision laser methane remote sensing instrument

Abstract

The invention discloses a miniature high-precision laser methane remote sensing instrument, and belongs to the technical field of gas detection. Through optimized layout and single key operation of core devices such as the driving board, the indicating laser, the TO laser, the photoelectric detector, the interference filter and the reference gas pool, the technical effects that the telemeter is miniaturized and can be held by one hand are achieved; self-calibration of emergent laser is achieved through the reference gas pool, correction of measured values is completed, actual measured values are corrected in combination with the temperature and pressure sensor, and the measurement accuracy of the remote measuring instrument is remarkably improved; in addition, an interference light filter is arranged in front of the front end of the photoelectric detector, so that the transmittance and narrow band-pass characteristic of measurement light are improved, and high-precision remote measurement of methane gas is realized.

Description

Technical Field

[0001] The invention relates to the technical field of laser spectrum gas detection, in particular to a miniature high-precision laser methane remote detection instrument. Background Art

[0002] Methane, as a common greenhouse gas and flammable and explosive gas, is widely present in natural gas, biogas, coalbed methane and certain industrial production processes. Its colorless and odorless characteristics make leakage difficult to detect. Therefore, timely and accurate detection of methane concentration is crucial to preventing safety accidents such as fire and explosion. Traditional gas detection methods such as catalytic combustion or infrared absorption may be interfered by environmental factors and require sampling contact. The laser methane telemeter based on TDLAS technology can achieve non-contact and long-distance measurement, which is suitable for monitoring dangerous or inaccessible environments. TDLAS technology uses the narrow linewidth characteristics of lasers to accurately detect methane at low concentration levels, and is not interfered by background gases. It has high sensitivity and measurement accuracy. Compared with traditional detection equipment, laser methane telemeters usually have lower maintenance costs and higher reliability, and also provide strong technical support for environmental protection and safe production.

[0003] However, although the size of existing laser gas telemeters is getting smaller and smaller, they are limited by the layout of core components and cannot be truly portable. They are not convenient to carry in pockets for measurement. At the same time, the complex multi-button setting increases the difficulty of use for operators and cannot achieve one-button measurement. Existing laser gas telemeters are easily affected by environmental factors such as temperature and pressure changes and laser drift during long-term use, which may affect the measurement results. At the same time, in open path measurements, atmospheric scattering, stray light and other interference may affect the measurement data and produce false alarms. Summary of the invention

[0004] In view of the above problems, the present invention provides a miniature high-precision laser methane telemeter. By optimizing the layout of core components and single-button operation, the telemeter is miniature and can be held in one hand. The self-calibration of the output laser is achieved through a reference gas pool to complete the correction of the measured value. The actual measured value is corrected in combination with a temperature and pressure sensor, which significantly improves the measurement accuracy of the telemeter. In addition, the pre-interference filter at the front end of the photodetector is used to improve the transmittance and narrow bandpass characteristics of the measuring light, thereby realizing high-precision remote sensing of methane gas.

[0005] To achieve the above object, the technical solution adopted by the present invention is.

[0006] A miniature high-precision laser methane telemeter, comprising a signal processing system, a photoelectric detector, an interference filter for accurately selecting the wavelength range of the transmission light of the measuring light and improving the transmittance and narrow bandpass of the measuring light, a receiving lens, a TO laser, a semi-transparent and semi-reflective lens, a reflector, a reference gas cell, and a temperature and pressure sensor for obtaining ambient temperature and pressure data and forming a correction factor 2 to correct the laser parameters; an interference filter is arranged at the front end of the photoelectric detector; The laser output by the TO laser forms measurement light and reference light after passing through a semi-transparent and semi-reflective lens. The measurement light passes through the gas to be measured and is output to the surface of the target object. After being reflected by the target object, it passes through the gas to be measured, a receiving lens, an interference filter, and a photoelectric detector in sequence and is output to a signal processing system. The reference light passes through a reflector and a reference gas cell in sequence, and the reference gas cell performs self-calibration on the laser to form a correction coefficient 1, which is output to the signal processing system to correct the laser parameters. By comparing the absorption spectra of the measurement light of the gas to be measured and the reference light of the reference gas cell, the high-precision measurement of the concentration of the gas to be measured is achieved in combination with the Lambert-Beer law.

[0007] Preferably, an adjustable collimator is provided in the middle of the TO laser and the semi-transparent and semi-reflective lens.

[0008] Preferably, the adjustable collimator comprises a lens holder, an optical collimating lens and a tube holder.

[0009] Preferably, the interference filter adopts a multi-layer thin film structure, and the transmission wavelength range of the measurement light is accurately selected through the interference effect of the multi-layer thin film.

[0010] Preferably, the laser methane telemeter also includes an indicator laser, a module fixing frame and a driving board for performing visible light pointing and auxiliary measurement of the gas to be measured and the target object.

[0011] Preferably, the indicator laser is a green laser.

[0012] Preferably, a layer of thermal conductive silicone grease is evenly coated on the contact surface between the indicator laser and the module fixing frame.

[0013] Preferably, the reference gas pool is provided with methane gas, CO gas or ammonia gas of standard absolute concentration.

[0014] Preferably, the driving board is installed at the rear end of the module fixing frame and is used to drive and power the TO laser, the indicator laser and the photoelectric detector.

[0015] Due to the adoption of the above technical solution, the present invention has the following beneficial effects.

[0016] (1) The present invention optimizes the layout of the optical machine module, drive board, indicator laser, TO laser, photodetector, interference filter, reference gas cell and other components to reduce the size of the telemeter body to a size that can be easily held in one hand. A single button operation is used to achieve one-button detection. At the same time, the entire telemeter is assembled with screws to ensure the structural stability of the telemeter. Anti-slip soft stickers are provided at both ends, which not only increases the comfort of hand-held grip, but also increases the appearance of the entire device.

[0017] (2) In order to solve the technical problem that the measurement results of the telemeter may be affected by environmental factors such as temperature and pressure changes and laser drift during long-term use, the present invention adds a built-in reference gas pool, which corrects the measured values ​​through direct self-calibration by light output. At the same time, the actual measured values ​​are corrected by adding a temperature and pressure sensor, thereby improving the measurement accuracy of the telemeter.

[0018] (3) The present invention aims to solve the technical problem that atmospheric scattering, stray light and other interferences may affect the measurement data in open path measurement. The present invention sets an interference filter at the front end of the photodetector. Compared with the traditional narrow-band filter with a single coating, the interference filter uses the interference effect of a multi-layer thin film to have a higher transmittance and a narrow bandpass characteristic, thereby further improving the accuracy of the measurement data. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The following is a detailed discussion of the making and application of the preferred embodiments of the present invention. However, it should be understood that the present invention provides many applicable inventive concepts that can be embodied in various specific environments. The specific embodiments discussed are only for the purpose of illustrating the specific ways of making and using the present invention, and do not limit the scope of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative work.

[0020] Figure 1 It is a structural schematic diagram of the present invention.

[0021] Figure 2 It is a schematic diagram of the three-dimensional structure decomposition of the present invention.

[0022] Figure 3 It is a schematic diagram of assembling the bottom shell and the anti-skid soft sticker of the present invention.

[0023] Figure 4 It is a schematic diagram of the assembly of the upper shell of the present invention.

[0024] Figure 5 It is a schematic diagram of the arrangement of the optomechanical module components of the present invention.

[0025] Figure 6 It is a schematic diagram of the structure of the adjustable collimator of the present invention.

[0026] Among them, 1-optical lens; 2-front shell; 3-anti-slip soft sticker; 4-high-transparency acrylic plate; 5-round button; 6-buffer sleeve; 7-adapter board; 8-rear shell; 801-TYPEC charging port; 9-main control board; 10-vibration motor; 11-buzzer; 12-lower shell; 13-upper shell; 1301-display window installation slot; 14-optical machine module; 141-indicator laser; 142-receiving lens; 143- Reflector; 144-semi-transparent and semi-reflective lens; 145-photoelectric detector; 146-reference gas pool; 147-driving board; 1471-temperature and pressure sensor; 1472-signal processing system; 150-adjustable collimator; 1501-lens holder; 1502-tube holder; 153-optical collimating lens; 154-module fixing frame; 16-anti-loosening screw; 17-battery; 1701-buffer cotton; 18-antenna board; 110-housing assembly. DETAILED DESCRIPTION

[0027] The following is a detailed discussion of the making and application of the preferred embodiments of the present invention. However, it should be understood that the present invention provides many applicable inventive concepts that can be embodied in various specific environments. The specific embodiments discussed are only intended to illustrate specific ways to make and use the present invention and do not limit the scope of the present invention.

[0028] The present invention aims at the technical problem that the telemeter is easily affected by environmental factors such as temperature and pressure changes and laser drift during long-term use, which may affect the measurement results. The present invention adds a built-in reference gas pool 146, which is directly self-calibrated by light output to complete the correction of the measured value. At the same time, the temperature and pressure sensor 1471 is added to correct the actual measured value, thereby improving the accuracy of the telemeter measurement. In addition, an interference filter is set at the front end of the photodetector 145. Compared with the traditional narrow-band filter with a single coating filter, the interference filter uses the interference effect of a multi-layer thin film to have a higher transmittance and narrow bandpass characteristics, further improving the accuracy of the measurement data.

[0029] The following is combined with Figure 1-6 Further elaboration.

[0030] like Figure 1 A miniature high-precision laser methane telemeter shown includes a signal processing system 1472, a photoelectric detector 145, an interference filter for accurately selecting the transmission wavelength range of the measuring light and improving the transmittance and narrow bandpass of the measuring light, a receiving lens 142, a TO laser, a semi-transparent and semi-reflective lens 144, a reflector 143, a reference gas pool 146 and a temperature and pressure sensor 1471 for obtaining ambient temperature and pressure data and forming a correction factor 2 to correct the laser parameters; an interference filter is arranged at the front end of the photoelectric detector 145.

[0031] The laser output by the TO laser forms measurement light and reference light after passing through the semi-transparent and semi-reflective lens 144. The measurement light passes through the gas to be measured and is output to the surface of the target object. After being reflected by the target object, it passes through the gas to be measured, the receiving lens 142, the interference filter, and the photoelectric detector 145 in sequence and is output to the signal processing system 1472. The reference light passes through the reflector 143 and the reference gas cell 146 in sequence, and the reference gas cell 146 performs self-calibration on the laser to form a correction coefficient 1, which is output to the signal processing system 1472 for correcting the laser parameters. By comparing the absorption spectra of the measurement light of the gas to be measured and the reference light of the reference gas cell 146, combined with the Lambert-Beer law, high-precision measurement of the concentration of the gas to be measured is achieved.

[0032] An adjustable collimator 150 is provided in the middle of the TO laser and the semi-transparent and semi-reflective lens 144. The adjustable collimator 150 includes a lens holder 1501, an optical collimating lens 153 and a tube holder 1502. The interference filter adopts a multi-layer film structure, and the wavelength range of the transmitted light of the measuring light is accurately selected through the interference effect of the multi-layer film. The laser methane telemeter also includes an indicator laser 141, a module fixing frame 154 and a driving board 147 for visible light pointing and auxiliary measurement of the gas to be measured and the target. The indicator laser 141 adopts a green laser. A layer of thermal conductive silicone grease is evenly coated on the contact surface between the indicator laser 141 and the module fixing frame 154. The reference gas pool 146 is provided with a standard absolute concentration of methane gas, CO gas or ammonia gas. The driving board 147 is installed at the rear end of the module fixing frame 154, and is used to drive and power the TO laser, the indicator laser 141 and the photodetector 145.

[0033] The following is combined with Figure 1-6 Further detailed explanation and introduction.

[0034] As attached Figure 2-3 The schematic diagram of the structure of a miniature high-precision laser methane telemeter is shown. The telemeter consists of a housing assembly 110 and an optical-mechanical module 14. The optical-mechanical module 14 is fixed to the housing assembly 110 by screws and installed inside the housing assembly 110. The anti-loosening screws 16 are used to fix it to increase the stability of the overall structure and prevent the device from falling and the optical-mechanical module 14 from being damaged. A group of anti-skid soft stickers 3 are set at the fixing position of the anti-loosening screws 16 on the outside of the housing. While covering the anti-loosening screws 16, it ensures that the telemeter is not easy to slip during handheld use. At the same time, the stripes 301 set on the anti-skid soft stickers 3 are both beautiful and anti-skid, which increases the comfort of hand-held feel. The anti-skid soft stickers 3 are fixed by 3M adhesive.

[0035] The housing assembly 110 includes an upper housing 13, a lower housing 12, a front housing 2, and a rear housing 8. The front housing 2 has three holes, one for an optical receiving lens, one for an indicating laser through hole, and one for a detecting laser through hole. An optical lens enhancement sheet 1 is provided in front of the detecting laser lens hole, which can protect the internal laser while increasing the transmittance of the detecting laser.

[0036] The bottom of the lower shell 12 is provided with a limiting column for fixing the optical-mechanical module 14, so as to ensure that the optical-mechanical module 14 is conveniently and quickly installed and at the same time increase the stability of the optical-mechanical module 14. The bottom of the lower shell 12 is also provided with a battery compartment for installing a battery 17, so as to ensure the relative independence of the battery 17. A pair of buffer cottons 1701 are provided when the battery 17 contacts the shell assembly 110, so as to ensure that the battery 17 has a vibration buffering effect during the use of the telemeter.

[0037] The rear end of the lower shell 12 is provided with a mounting slot for a buzzer 11 and a mounting slot for a vibration motor 10. A sound-permeable hole is provided at the bottom of the mounting slot for the buzzer 11 to ensure that the sound of the buzzer 11 can be transmitted through the shell. At the same time, in order to avoid the risk of water ingress, a waterproof sound-permeable membrane is provided in front of the selected buzzer 11. An antenna mounting slot is provided on the left side of the lower shell 12, and an antenna board 18 is installed in the antenna mounting slot, and one end is connected to the main control board 9 through an IPX line to ensure the data transmission performance of the telemeter.

[0038] The rear shell 8 panel is provided with a TYPEC charging hole 801, and the TYPEC charging connector of the main control board 9 is a waterproof connector. At the same time, since the shell material is metal aluminum alloy 6061, in order to prevent TYPEC from conducting electricity through the shell assembly 110, an adapter plate 7 is arranged at the contact position between the rear shell 8 and the TYPEC. The material of the adapter plate 7 is ABS, and a pair of support columns 701 are arranged on the adapter plate 7 for supporting the main control board 9.

[0039] like Figure 2 As shown, the upper shell 13 is provided with a display window installation slot 1301, and a high-transparency acrylic plate 4 is installed in the display window to protect the display screen. At the same time, a round button 5 is arranged in the middle of the upper shell 13, and a button buffer cover 6 is arranged at the lower part of the button. The button buffer cover 6 is made of silicone material, which is first assembled with the button through the card slot and then fixed with the upper shell 13 by screws. While protecting the main control board 9, it also increases the resilience of pressing. Figure 4 shown.

[0040] like Figure 5As shown, the optical machine module 14 includes an adjustable collimator 150, an indicator laser 141, a TO laser 148, a photodetector 145, an interference filter 152, a receiving lens 142, a reference gas pool 146, a temperature and pressure sensor 1471, a reflector 143, a semi-transparent and semi-reflective lens 144, a module fixing frame 154, and a driving plate 147. The adjustable collimator 150 is composed of a lens holder 1501 and a tube holder 1502. An optical collimating lens 153 is installed at the front end of the lens holder 1501, and a TO laser 148 is installed at the rear end of the tube holder 1502. The lens holder 1501 and the tube holder 1502 are connected by threads, and the distance between the two can be adjusted, and the size of the light spot can be further adjusted. Due to the problem of the manufacturing process of the TO laser 148, it is impossible to achieve consistency in the light output angle and the light spot size. The adjustable collimator 150 ensures the consistency of the size of the light spot emitted by the TO laser 148, and further improves the stability of the telemeter. A heat sink 149 is provided at the rear end of the TO laser 148. The main material of the heat sink 149 is brass. The heat sink 149 is used for heat dissipation of the TO laser 148 to increase the service life of the laser. Figure 6 shown.

[0041] The indicator laser 141 uses a green laser, which has extremely high beam concentration and energy concentration, and can maintain the clarity of the light spot after long-distance transmission. However, the green light accumulates heat seriously during long-term use. The indicator laser 141 is installed on the module fixing frame 154. The main body of the module fixing frame 154 is made of aluminum, which has good thermal conductivity. At the same time, a layer of thermal conductive silicone grease is applied to the contact between the indicator laser 141 and the module fixing frame 154 to increase the overall heat dissipation performance of the indicator laser 141.

[0042] An interference filter 152 is arranged in front of the photodetector 145, and the interference filter 152 uses the interference effect of multi-layer thin films to accurately select the wavelength range of light to be transmitted. It has high transmittance and narrow bandpass characteristics, and can accurately control the absorption wavelength of methane.

[0043] A semi-transparent and semi-reflective lens 144 is arranged at the front end of the adjustable collimator 150. The light emitted by the TO laser 148 is collimated, and a part of the light is emitted through the semi-transparent and semi-reflective lens 144, directed to the target detection object, received by the receiving lens 142 after reflection, and focused and output to the photoelectric detector 145 after the interference filter 152 further improves the transmittance and narrow bandpass characteristics of the measurement light. The photoelectric detector 145 converts the optical signal into an electrical signal and outputs it to the signal processing system 1472 for comparison and calculation of the absorption spectrum; the other part is reflected to the reflector 143 through the semi-transparent and semi-reflective lens 144, and then reflected to the reference gas cell 146. The reference gas cell 146 performs self-calibration on the output light measurement, forms a correction coefficient and outputs it to the signal processing system 1472, automatically completing the power-on self-check and self-calibration operation. Conventional equipment calibration uses external references and requires separate calibration before each measurement, which increases the complexity of operation. The telemeter uses self-calibration and can complete the calibration process every time it is powered on and self-checked. At the same time, each measured value will be compared and corrected based on the correction factor 1 fed back by the reference gas pool 146 to increase the accuracy of the measurement.

[0044] The selected reference gas cell 146 contains an absolute concentration of methane gas to ensure the accuracy of the measurement results. By comparing the absorption spectrum of the gas to be measured with the spectrum of the reference gas cell 146, the concentration of the gas in the actual sample can be determined. A temperature and pressure sensor 1471 is set on the driving board 147 to identify the ambient temperature and pressure during the use of the telemeter. During the equipment calibration process, a correction coefficient 2 is formed based on the ambient temperature and pressure and fed back to the signal processing system 1472. The numerical value of each measurement is compared and corrected to further increase the accuracy of the measurement. The driving board 147 is installed at the rear end of the module fixing frame 154 and fixed with screws. It drives and powers the TO laser 148, the indicator laser 141, the photodetector 145, and the reference gas cell 146, and pre-processes the measurement data and outputs it to the main control board 9.

[0045] The present invention optimizes the layout of components such as the optical machine module 14, the drive board 147, the indicator laser 141, the TO laser, the photodetector 145, the interference filter, and the reference gas cell 146, so that the size of the telemeter body can be easily held in one hand, and one-key detection is achieved by a single button operation. At the same time, the whole is assembled with screws to ensure the structural stability of the telemeter. Anti-slip soft stickers 3 are provided at both ends, which not only increases the comfort of hand-held grip, but also increases the appearance of the entire machine.

[0046] Although the specification has been described in detail, it should be understood that various changes, substitutions and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims. In addition, the specific embodiments described are not intended to limit the scope of the invention, and those of ordinary skill in the art can easily understand based on the present invention that currently existing or later to be developed processes, machines, manufactures, material compositions, means, methods, or steps can perform substantially the same functions as the embodiments of the present invention or obtain substantially the same results. Therefore, the appended claims are intended to include such processes, machines, manufactures, material compositions, means, methods or steps within their scope.

Claims

1. A miniature high-precision laser methane remote sensing instrument, characterized in that: It includes a signal processing system, a photoelectric detector, an interference filter for accurately selecting the wavelength range of the transmission light of the measuring light and improving the transmittance and narrow bandpass of the measuring light, a receiving lens, a TO laser, a semi-transparent and semi-reflective lens, a reflector, a reference gas cell, and a temperature and pressure sensor for obtaining the ambient temperature and pressure data and forming a correction factor 2 to correct the laser parameters; the interference filter is arranged at the front end of the photoelectric detector; The laser output by the TO laser forms measurement light and reference light after passing through a semi-transparent and semi-reflective lens. The measurement light passes through the gas to be measured and is output to the surface of the target object. After being reflected by the target object, it passes through the gas to be measured, a receiving lens, an interference filter, and a photoelectric detector in sequence and is output to a signal processing system. The reference light passes through a reflector and a reference gas cell in sequence, and the reference gas cell performs self-calibration on the laser to form a correction coefficient 1, which is output to the signal processing system to correct the laser parameters. By comparing the absorption spectra of the measurement light of the gas to be measured and the reference light of the reference gas cell, the high-precision measurement of the concentration of the gas to be measured is achieved in combination with the Lambert-Beer law.

2. A miniature high-precision laser methane remote sensing instrument as claimed in claim 1, characterized in that: An adjustable collimator is arranged in the middle of the TO laser and the semi-transparent and semi-reflective lens.

3. A miniature high-precision laser methane remote sensing instrument as claimed in claim 2, characterized in that: The adjustable collimator comprises a lens seat, an optical collimating lens and a tube seat.

4. A miniature high-precision laser methane remote sensing instrument as claimed in claim 1, characterized in that: The interference filter adopts a multi-layer thin film structure, and accurately selects the transmission light wavelength range of the measurement light through the interference effect of the multi-layer thin film.

5. A miniature high-precision laser methane remote sensing instrument as claimed in claim 1, characterized in that: The laser methane telemeter also includes an indicating laser, a module fixing frame and a driving board for performing visible light pointing and auxiliary measurement of the gas to be measured and the target object.

6. A miniature high-precision laser methane remote sensing instrument as claimed in claim 5, characterized in that: The indicator laser is a green laser.

7. A miniature high-precision laser methane remote sensing instrument as claimed in claim 6, characterized in that: A layer of thermal conductive silicone grease is evenly coated on the contact surface between the indicator laser and the module fixing frame.

8. A miniature high-precision laser methane remote sensing instrument as claimed in claim 1, characterized in that: The reference gas pool is provided with methane gas, CO gas or ammonia gas of standard absolute concentration.

9. A miniature high-precision laser methane remote sensing instrument as claimed in claim 5, characterized in that: The driving board is installed at the rear end of the module fixing frame and is used to drive and supply power to the TO laser, the indicator laser and the photoelectric detector.

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