Long-optical-path multi-reflection type oxygen concentration detection device

Abstract

The utility model provides a long-optical-path multi-reflection type oxygen concentration detection device which is used for solving the technical problems that an existing oxygen concentration detection device is low in identifiability and not high in sensitivity. The device comprises a laser transmit-receive optical system, a controller and a drive control unit, the controller is connected with the drive control unit, the drive control unit is connected with a laser of the laser transmit-receive optical system, a photoelectric detector of the laser transmit-receive optical system is connected with the controller, the laser transmit-receive optical system further comprises a gas absorption cell, and the gas absorption cell is connected with the controller. A long-optical-path multiple-reflection optical system is arranged in the gas absorption cell, the laser is arranged in front of a light input port of the long-optical-path multiple-reflection optical system, and the photoelectric detector is arranged on a light path of a light output port of the long-optical-path multiple-reflection optical system. The device has high resolution, and interference with other molecules can be avoided; the structure is simple and easy to realize; not only is the operation easy, but also the cost is effectively saved; the measurement process is very easy to realize and the practicability is very strong.

Description

Technical Field

[0001] The utility model relates to the technical field of concentration detection, in particular to a long optical path oxygen concentration detection device. Background Art

[0002] Oxygen (O2) is not only a key component of the atmosphere but also a vital gas in industrial production processes and medical equipment. Monitoring oxygen concentration plays a vital role in environmental monitoring and industrial process control. In industrial production, in particular, oxygen is a crucial combustion aid. Adjusting oxygen concentration can reduce pollutant emissions and effectively minimize environmental pollution. Furthermore, when oxygen concentrations reach dangerous levels during combustion, they can cause explosions and other accidents, resulting in significant loss of life and property. Traditional oxygen detection methods have varying measurement principles depending on the application requirements and measurement environment, primarily including ultrasonic, paramagnetic, galvanic cell, zirconia, and fluorescence quenching methods. This utility model primarily introduces a detection method based on TDLAS technology.

[0003] Traditional oxygen measurement methods have the following main shortcomings: First, these methods cannot effectively identify the gas to be measured in the mixed gas, and due to their low recognition, they are not sensitive. These problems may affect the long-term stability and performance of the instrument, thereby affecting the accuracy of the measurement results; second, traditional measurement methods have a complex measurement process, high system stability requirements, and require system calibration and maintenance, which cannot meet long-term working requirements.

[0004] The measurement of gas concentration based on tunable semiconductor laser absorption spectroscopy (TDLAS) has the advantages of fast response speed, accurate measurement results, simple and stable measurement system, etc. It has very good adaptability to harsh measurement environments and is suitable for application in industrial production, medical equipment, aerospace and other fields.

[0005] The invention patent with application number 202010603015.2 discloses a long optical path gas detection system based on a quantum cascade laser, comprising: a light source control module for outputting light; an optical path auxiliary module for collimating the light output from the light source control module, and the collimated light enters a long optical path gas chamber; a long optical path gas chamber for accommodating the gas to be measured, and outputting the collimated light after multiple refractions and reflections; a photoelectric detector for detecting the output light of the long optical path gas chamber and converting the detected light signal into an electrical signal; a photoelectric signal acquisition module for collecting the electrical signal emitted by the photoelectric detector and analyzing the electrical signal to obtain the concentration of the gas to be measured. The above-mentioned long optical path gas chamber refracts and reflects the light entering the long optical path gas chamber multiple times, thereby increasing the optical path of the incident light, thereby improving the detection accuracy of the detection system. However, the above-mentioned patent has a large number of lenses and prisms in the entire system, making it difficult to adjust the optical path. Utility Model Content

[0006] In response to the technical problems of low recognition and low sensitivity of existing oxygen concentration detection devices, the utility model proposes a long-path multiple-reflection oxygen concentration detection device that can detect and distinguish the unique absorption spectral lines related to oxygen in the mixed gas, and then calculate and process the identified spectral lines to achieve qualitative and quantitative analysis of oxygen.

[0007] In order to achieve the above-mentioned purpose, the technical solution of the present invention is implemented as follows: a long optical path multiple reflection type oxygen concentration detection device includes a laser transceiver optical system, a controller and a drive control unit, the controller is connected to the drive control unit, the drive control unit is connected to the laser of the laser transceiver optical system, the photoelectric detector of the laser transceiver optical system is connected to the controller, the laser transceiver optical system also includes a gas absorption cell, a long optical path multiple reflection optical system is provided in the gas absorption cell, the laser is arranged in front of the light input port of the long optical path multiple reflection optical system, and the photoelectric detector is arranged on the optical path of the light output port of the long optical path multiple reflection optical system.

[0008] Preferably, the laser is a tunable semiconductor laser.

[0009] Preferably, the laser is a 760nm laser, which can output 760nm collimated light without the need for an additional optical path auxiliary module.

[0010] Preferably, a front lens is provided in front of the gas absorption cell, and the front lens is arranged on the optical path between the gas absorption cell and the laser and the photodetector respectively.

[0011] Preferably, the long optical path multiple reflection optical system comprises a first reflector and a second reflector, the first reflector and the second reflector are arranged opposite to each other and spaced apart; the second reflector is provided with a light input port and a light output port.

[0012] Preferably, the first reflector is a plane reflector, and the second reflector is a concave reflector.

[0013] Preferably, the photodetector is connected to the controller via a signal amplification module to amplify the signal collected by the photodetector.

[0014] Preferably, the driving control unit includes a temperature control unit and a current driving unit, the controller is connected to the temperature control unit and the current driving unit respectively, and the temperature control unit and the current driving unit are both connected to the controller.

[0015] Preferably, the controller is a single chip microcomputer, which is provided with a phase-locked amplifier circuit.

[0016] Preferably, the single chip microcomputer is connected to a display screen.

[0017] Compared with the existing technology, the beneficial effects of this utility model are: it can meet the monitoring and early warning needs of fast detection speed, high accuracy and few false alarms, and make up for the defects of existing detection methods and technologies. At the same time, it also has:

[0018] 1. Its most significant feature is its high resolution and ability to avoid interference with other molecules, which is unmatched by other measurement technologies.

[0019] 2. The structure is simple, very easy to implement, and can be self-calibrated in the air, and can be widely used in production and life;

[0020] 3. The system is not only easy to operate but also effectively saves costs and is more easily applied to real-time monitoring in industrial processing and production;

[0021] 4. Fast response speed, very conducive to achieving fast real-time online gas monitoring in industrial field applications.

[0022] 5. The measurement process is very easy to implement and highly practical. Usually, it is only necessary to tune the laser and scan the wavelength within a certain range to detect different types of gases. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 It is a structural diagram of the present utility model.

[0025] Figure 2 for Figure 1 Schematic diagram of the structure of the long optical path multiple reflection optical system in the gas absorption cell shown.

[0026] Figure 3 for Figure 2 The optical path simulation diagram of the long optical path multiple reflection optical system shown.

[0027] Among them, 1 is a temperature control unit, 2 is a current driving unit, 3 is a laser, 4 is a front lens, 5 is a gas absorption cell, 51 is a light input port, 52 is a light output port, 53 is a first reflector, 54 is a second reflector, 6 is a photodetector, 7 is a signal amplification module, and 8 is a controller. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] like Figure 1 As shown, a long optical path multiple reflection type oxygen concentration detection device includes a laser transceiver optical system, a controller 8 and a drive control unit. The laser transceiver optical system is used to transmit and receive laser light. The controller 8 is connected to the drive control unit. The drive control unit is connected to the laser 3 of the laser transceiver optical system. The drive control unit is used to drive and temperature control the laser 3. The laser 3 emits a detection laser. The photoelectric detector 6 of the laser transceiver optical system is connected to the controller 8. The photoelectric detector 6 is used to receive the laser light after passing through the target gas and convert it into an electrical signal and transmit it to the controller 8. The laser transceiver optical system also includes a gas absorption cell 5. The gas absorption cell 5 is encapsulated with standard concentration oxygen as the target gas. The gas absorption cell 5 is provided with a long optical path multiple reflection optical system. The long optical path multiple reflection optical system causes the incoming detection light to be reflected multiple times in the gas absorption cell 5. A longer optical path can be achieved in a smaller structural size, thereby reducing the volume of the device. Figure 2 As shown, laser 3 is positioned in front of the optical input port 51 of the long optical path multiple reflection optical system, ensuring that the detection laser light emitted by laser 3 can enter the long optical path multiple reflection optical system. Photodetector 6 is positioned in the optical path of the optical output port 52 of the long optical path multiple reflection optical system, ensuring that the laser light after passing through the gas absorption cell 5 is transmitted to photodetector 6. Photodetector 6 is model PDCT01-205. The controller 8 is a single-chip microcomputer equipped with a phase-locked amplifier circuit. The model of the single-chip microcomputer is STM32G431CBT6. The single-chip microcomputer is connected to a display screen, which is used to display the obtained oxygen concentration.

[0030] Furthermore, laser 3 is a tunable semiconductor laser. It is a 760nm laser that can output 760nm collimated light, eliminating the need for an additional optical path auxiliary module. Laser 3 model is XWVLD9A77-H-W53-S197-C752-P2.

[0031] Furthermore, in order to meet the explosion-proof requirements of the product, a front lens 4 is provided in front of the gas absorption cell 5 , and the front lens 4 is arranged on the optical path between the gas absorption cell 5 and the laser 3 and the photodetector 6 respectively.

[0032] The drive control unit includes a temperature control unit 1 and a current drive unit 2. A controller 8 is connected to the temperature control unit 1 and current drive unit 2, respectively. Both the temperature control unit 1 and current drive unit 2 are connected to the controller 8. The temperature control unit 1 adjusts the temperature inside the laser 3 in real time, ensuring that the wavelength output by the laser 3 is always locked to the absorption peak of the target gas. The current drive unit 2 is used to provide the operating drive current for the laser 3. The temperature control unit 1 is a temperature control chip with a model number of SGM41296, and the current drive unit 2 is an operational amplifier chip with a model number of SGM8541. The photodetector 6 is connected to the controller 8 via a signal amplification module 7, which amplifies the converted electrical signal and transmits it to the controller 8. The signal amplification module 7 is an operational amplifier chip with a model number of SGM8541.

[0033] The laser driving signal output by the single-chip microcomputer is transmitted to the laser current driving module, which drives the 760nm laser to emit a detection laser. The detection laser passes through the front lens 4 and enters the gas pool. After multiple reflections in the gas absorption pool 5, it passes through the front lens 4 again and enters the photodetector 6. The photodetector 6 is a silicon detector. The return light signal absorbed by the target gas undergoes photoelectric conversion by the photodetector 6, enters the single-chip microcomputer through the signal amplification module 7, and is converted and calculated by the phase-locked amplifier circuit in the single-chip microcomputer to obtain the concentration information of the target gas.

[0034] like Figure 2 As shown, the long optical path multiple reflection optical system includes a first reflector 53 and a second reflector 54. The first reflector 53 and the second reflector 54 are arranged opposite each other and spaced apart to facilitate multiple reflections of the detection laser light within the target gas. The first reflector 53 is provided with a light input port 51 and a light output port 52 to facilitate the entry and output of the detection laser light. The first reflector 53 is a plane reflector, and the second reflector 54 is a concave reflector. The first and second reflectors 53 and 54 form a multiple reflection optical system, which can achieve a long optical path within a compact structure. The collimated light beam emitted by the laser 3 enters the gas absorption cell 5 through the light input port 51 and undergoes multiple reflections between the first and second reflectors 53 and 54 before being emitted through the light output port 52. By adjusting the distance between the first and second reflectors 53 and 54, the number of reflections within the gas absorption cell 5 cavity can be adjusted, thereby extending the optical path within a limited space and achieving higher detection accuracy.

[0035] The oxygen concentration detection process of the present invention is as follows: First, oxygen of standard concentration is prepared and introduced into a gas absorption cell 5 for measurement. A single-chip microcomputer generates a modulation signal, and a current drive unit 2 modulates the wavelength of a laser 3. The laser light emitted by the laser 3 scans near the wavelength of a specific spectral line of the gas to be measured, then enters the gas absorption cell 5 and is partially absorbed by the gas to be measured. The temperature control unit 1 includes a semiconductor cooler drive unit, which ensures that the laser 3 operates at the set temperature while maintaining a stable output power. After passing through the gas absorption cell 5, the light is absorbed by the oxygen in the mixed gas. The transmitted light signal is received by a silicon detector and converted into a voltage signal. Due to its small amplitude, this signal is amplified by a pre-installed signal amplifier module 7 and then phase-sensitively demodulated using the phase-locked amplifier circuit of the single-chip microcomputer. After demodulation, a harmonic signal is obtained from the phase-locked amplifier. This signal amplitude is proportional to the gas concentration and carries gas information. After the single-chip microcomputer collects the signal and processes it using existing direct absorption methods, the oxygen concentration in the mixed gas is calculated and displayed on a liquid crystal display.

[0036] The long optical path multiple reflection process is as follows: the collimated light beam enters through the light input port 51 and first reaches the surface of the second reflector 54. According to the reflection law, it is reflected by the second reflector 54 to the surface of the first reflector 53, forming a first group of reflected light beams. Then, the collimated light beam reaches the second reflector 54 after being reflected by the first reflector 53. Subsequently, according to the reflection law, it is reflected multiple times between the first reflector 53 and the second reflector 54, as shown in FIG. Figure 3 As shown, a circle of reflected light spots is ultimately formed on each of the first and second reflectors 53 and 54. The number of light spots can be used to determine the number of reflections and the effective optical path length. Adjusting the distance between the first and second reflectors 53 and 54 changes the number of reflections. While maintaining a fixed structural length, the effective optical path length can be varied to enable detection of varying concentrations. The device automatically performs a self-calibration procedure upon startup to ensure accurate measurement results.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A long optical path multiple reflection type oxygen concentration detection device, comprising a laser transceiver optical system, a controller (8) and a drive control unit, wherein the controller (8) is connected to the drive control unit, the drive control unit is connected to the laser (3) of the laser transceiver optical system, and the photoelectric detector (6) of the laser transceiver optical system is connected to the controller (8), characterized in that: The laser transceiver optical system further comprises a gas absorption cell (5), wherein a long optical path multiple reflection optical system is provided in the gas absorption cell (5), the laser (3) is arranged in front of the light input port (51) of the long optical path multiple reflection optical system, and the photodetector (6) is arranged on the optical path of the light output port (52) of the long optical path multiple reflection optical system.

2. The long optical path multiple reflection type oxygen concentration detection device according to claim 1, characterized in that: The laser (3) is a tunable semiconductor laser.

3. The long optical path multiple reflection type oxygen concentration detection device according to claim 2, characterized in that: The laser (3) is a 760nm laser.

4. The long optical path multi-reflection oxygen concentration detection device according to any one of claims 1 to 3, characterized in that: A front lens (4) is provided in front of the gas absorption cell (5), and the front lens (4) is arranged on the optical path between the gas absorption cell (5) and the laser (3) and the photodetector (6).

5. The long optical path multi-reflection type oxygen concentration detection device according to claim 4, characterized in that: The long optical path multiple reflection optical system comprises a first reflector (53) and a second reflector (54), wherein the first reflector (53) and the second reflector (54) are arranged opposite to each other and spaced apart; and the second reflector (54) is provided with a light input port (51) and a light output port (52).

6. The long optical path multi-reflection type oxygen concentration detection device according to claim 5, characterized in that: The first reflector (53) is a plane reflector, and the second reflector (54) is a concave reflector.

7. The long optical path multi-reflection type oxygen concentration detection device according to claim 5 or 6, characterized in that: The photoelectric detector (6) is connected to the controller (8) via a signal amplification module (7).

8. The long optical path multi-reflection type oxygen concentration detection device according to claim 7, characterized in that: The drive control unit comprises a temperature control unit (1) and a current drive unit (2); the controller (8) is connected to the temperature control unit (1) and the current drive unit (2), respectively; and the temperature control unit (1) and the current drive unit (2) are both connected to the controller (8).

9. The long optical path multi-reflection type oxygen concentration detection device according to claim 8, characterized in that: The controller (8) is a single chip microcomputer, and a phase-locked amplifier circuit is provided inside the single chip microcomputer.

10. The long optical path multi-reflection type oxygen concentration detection device according to claim 9, characterized in that: The single chip microcomputer is connected to the display screen.

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