Multi-point laser multi-component gas measuring device

Abstract

The utility model relates to the technical field of gas detection, in particular to a multi-point laser multi-component gas measuring device which comprises a wide tuning spectrum light source, an optical fiber coupling lens, a frequency modulator, an optical fiber beam splitter, a gas standard pool, an optical absorption pool, a photoelectric detector and a controller, the wide tuning spectrum light source is in optical fiber connection with the frequency modulator through the optical fiber coupling lens, the frequency modulator is in optical fiber connection with the input end of the optical fiber beam splitter, and the output end of the optical fiber beam splitter is respectively connected to the gas standard pool and the optical absorption pool through transmission optical fibers. Output ports of the gas standard cell and the optical absorption cell are respectively connected with a photoelectric detector, the photoelectric detector is electrically connected with a controller, and the controller is electrically connected with a wide tuning spectrum light source. The wide tuning spectrum light source is adopted to improve the output power of the laser, the optical fiber beam splitter is adopted to carry out multi-point distributed measurement, and the device can be widely applied to in-situ gas measurement of multiple components in a coal mine.

Description

Technical Field

[0001] The utility model relates to the technical field of gas detection, in particular to a multi-point laser multi-component gas measuring device. Background Art

[0002] Mine fire is one of the main disasters in coal mines. When a fire occurs, a large amount of high-temperature smoke and toxic and harmful gases will be produced, which will cause harm to underground personnel. Mine fires are also prone to cause gas and coal dust explosions, causing more serious disasters. Therefore, mine fire prevention and control is an important task for coal mine safety production.

[0003] Highly sensitive real-time monitoring of multi-component gases such as carbon monoxide, methane, carbon dioxide, acetylene, and ethylene can effectively provide early warning of mine fires. At present, laser fiber distributed gas measurement technology can achieve single-point measurement, but due to the weak energy of the laser, it is difficult to distribute to multiple optical probes. And as the area of ​​the mining area increases, there are obvious defects in using multiple laser light sources to achieve multiple point measurements. The inconsistent performance between different laser light sources leads to low measurement accuracy; the increase in the number of laser light sources also increases the workload and maintenance costs. Utility Model Content

[0004] In order to solve the above problems, the utility model provides a multi-point laser multi-component gas measuring device.

[0005] The technical solution is as follows:

[0006] A multi-point laser multi-component gas measurement device comprises a wide-tuning spectrum light source, a fiber coupling lens, a frequency modulator, a fiber beam splitter, a gas standard cell, an optical absorption cell, a photodetector and a controller. The wide-tuning spectrum light source is connected to the frequency modulator optical fiber via the fiber coupling lens, the frequency modulator is connected to the input end optical fiber of the fiber beam splitter, the output end of the fiber beam splitter is respectively connected to the gas standard cell and the optical absorption cell via a transmission optical fiber, the output ports of the gas standard cell and the optical absorption cell are respectively connected to the photodetector, the photodetector is electrically connected to the controller, and the controller is electrically connected to the wide-tuning spectrum light source.

[0007] The controller includes a multi-channel data acquisition card, a processing module, a high-speed phase lock, a microwave source and a frequency multiplier. The multi-channel data acquisition card is electrically connected to the photodetector, the processing module is electrically connected to the multi-channel data acquisition card, the high-speed phase lock and the microwave source respectively, the processing module is electrically connected to the wide tuning spectrum light source, and the microwave source is connected to the high-speed phase lock via the frequency multiplier.

[0008] As a specific implementation, the optical fiber beam splitter is a two-way optical fiber beam splitter, wherein one optical path is connected to the second optical fiber beam splitter, and the second optical fiber beam splitter is connected to the gas standard cell via a transmission optical fiber.

[0009] The other optical path of the two-way optical fiber splitter is connected to the third optical fiber splitter, and the third optical fiber splitter is connected to the optical absorption cell via a transmission optical fiber.

[0010] The 2-way optical fiber beam splitter is a 99 / 1 optical fiber beam splitter.

[0011] The gas standard pool includes a carbon monoxide standard pool, a methane standard pool, a carbon dioxide standard pool, an acetylene standard pool and an ethylene standard pool.

[0012] The wide tunable spectrum light source comprises a seed laser and an optical parameter module, and the optical parameter module is connected to the seed laser.

[0013] The photoelectric detector includes a single-channel photoelectric detector and a multi-channel photoelectric detector. The signal input end of the single-channel photoelectric detector is connected to the output port optical fiber of the gas standard cell, and the signal input end of the multi-channel photoelectric detector is connected to the output port optical fiber of the optical absorption cell.

[0014] An optical lens is also arranged between each output light path of the third optical fiber beam splitter and the optical absorption cell.

[0015] In order to achieve high-sensitivity measurement of trace gases such as CO, the length of the optical absorption cell is greater than 500 m.

[0016] The beneficial effects are as follows: the utility model is a multi-point laser multi-component gas measurement device, which increases the laser output power by adopting a wide-tuned spectrum light source, uses an optical fiber beam splitter for multi-point distributed measurement, and realizes simultaneous measurement of multiple gases through a gas standard cell. It can be widely used in in-situ gas measurement of multiple components in coal mines, and realizes effective detection of mine fire prevention and control; at the same time, a frequency modulator is used to modulate the laser, which can meet the light intensity requirements of a long optical path optical absorption cell and improve measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural diagram of a multi-point laser multi-component gas measurement device;

[0018] Figure 2 This is a schematic diagram of the controller structure. DETAILED DESCRIPTION

[0019] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings.

[0020] Example

[0021] See also Figure 1 This embodiment provides a multi-point laser multi-component gas measurement device, including a wide-tuning spectrum light source, a fiber-coupled lens, a frequency modulator, a fiber beam splitter, a gas standard cell, an optical absorption cell, a photodetector and a controller.

[0022] The wide-tuned spectrum light source is located at the initial end of the optical path of the entire device, and is electrically connected to the controller, and can receive the driving signal of the controller to generate a scanning laser. Its output end is coupled to a single-mode optical fiber through a fiber coupling lens, and the single-mode optical fiber is connected to the input end of a frequency modulator. The frequency modulator can modulate the intensity of the scanning laser emitted by the wide-tuned spectrum light source. The frequency modulator is connected to the input end of the fiber optic splitter, and the fiber optic splitter can divide the modulated laser into two paths, one of which is connected to the gas standard cell through a transmission optical fiber, and the other is connected to the optical absorption cell through a transmission optical fiber. The scanning laser enters from one end of the gas standard cell and the optical absorption cell respectively, and is detected by a photodetector connected to the other end. The photodetector can convert the detected optical signal into an electrical signal. The photodetector is connected to the controller and can transmit the detection signal to the controller for processing.

[0023] The wide-tunable spectrum light source includes a seed laser and an optical parameter module. The optical parameter module is connected to the seed laser. The laser wavelength generated by the seed laser is 1064nm, and its current can be adjusted in the range of 0-100mA, so that the laser output power is 500mW, which is equivalent to the output power of 50 semiconductor lasers. The optical parameter module can receive the laser wavelength tuning signal of the controller and use the optical parameter module to modulate the seed laser so that the output band range of the wide-tunable spectrum light source is 1500nm-1650nm, forming a scanning laser beam.

[0024] In a specific embodiment, the laser beam output by the wide-tuned spectrum light source is collimated by a fiber coupling lens and coupled to a single-mode optical fiber. The single-mode optical fiber is subjected to high-frequency micro-frequency modulation by an EOM frequency regulator, and modulated laser light is generated after intensity modulation. Then the beam is split by a fiber optic beam splitter, and the fiber optic beam splitter is a 2-way fiber optic beam splitter. Among them, the 2-way fiber optic beam splitter is a 99 / 1 fiber optic beam splitter, and the intensity-modulated laser beam is divided into two paths by the 99 / 1 fiber optic beam splitter, one of which is connected to the second fiber optic beam splitter, and the second fiber optic beam splitter is connected to the gas standard cell via a transmission optical fiber, so that the low-energy modulated laser light can be reflected and absorbed in the gas standard cell; the other optical path of the 2-way fiber optic beam splitter is connected to the third fiber optic beam splitter, and the third fiber optic beam splitter is connected to the optical absorption cell via a transmission optical fiber, so that the high-energy modulated laser light is transmitted in the optical absorption cell, and finally the signal is measured by the acquisition and detection of the photoelectric detector to realize the gas signal measurement of the gas standard cell.

[0025] In this embodiment, the second optical fiber beam splitter can be a 5-way optical fiber beam splitter, and the gas standard pool includes a carbon monoxide standard pool, a methane standard pool, a carbon dioxide standard pool, an acetylene standard pool, and an ethylene standard pool, which can split one path of low-energy modulated laser into five paths, and independently enter the gas standard pools of five different gases. The third optical fiber beam splitter can be a 64-way optical fiber beam splitter, which can split a large-energy modulated laser into 64 paths.

[0026] In order to achieve multi-point gas measurement, several optical absorption cells are provided, and the length of the optical absorption cells is greater than 500m. Each optical path of the third optical fiber beam splitter is coupled to the optical absorption cell with a long optical path through an optical lens, which can effectively achieve high-sensitivity measurement of trace gases such as CO.

[0027] In a specific embodiment, the photoelectric detector includes a single-channel photoelectric detector and a multi-channel photoelectric detector. The single-channel photoelectric detector is independently connected to the output port of each gas standard cell through an optical fiber, and the multi-channel photoelectric detector is connected to an optical absorption cell to receive the light signal reflected and absorbed by the optical absorption cell, and transmit it to the controller after photoelectric conversion to realize multi-point gas measurement.

[0028] See also Figure 2 The controller includes a multi-channel data acquisition card, a processing module, a high-speed phase lock, a microwave source and a frequency multiplier. The processing module model is STM32F303RBT6. The multi-channel data acquisition card is electrically connected to the photodetector. The processing module is electrically connected to the multi-channel data acquisition card, the high-speed phase lock and the microwave source respectively. The processing module is electrically connected to the wide tuning spectrum light source, and the microwave source is connected to the high-speed phase lock via the frequency multiplier. The processing module drives the wide-tuned spectrum light source to output scanning laser through serial communication. The scanning laser is divided into a large energy modulated laser and a small energy modulated laser by a 99 / 1 optical fiber beam splitter after intensity modulation by a frequency modulator. The small energy modulated laser passes through a carbon monoxide gas standard cell, a methane gas standard cell, a carbon dioxide gas standard cell, an acetylene gas standard cell, and an ethylene gas standard cell, and is detected by a single-channel photoelectric detector and converted into an electrical signal and transmitted to a multi-channel data acquisition card. If the controller detects that there is a gas absorption signal in one of the five gas standard cells, the controller adjusts the wide-tuned spectrum light source to keep the wavelength of its scanning laser on the current absorption peak, and triggers the microwave source to generate a high-frequency microwave signal. The high-frequency microwave signal is transmitted to a high-speed phase lock as a reference signal through a frequency multiplier. At the same time, the multi-channel data acquisition card collects optical signals from several optical absorption cells, and transmits the converted electrical signals to the high-speed phase lock in chronological order. The processing module collects the signals after phase-locked demodulation by the high-speed phase lock, thereby realizing the measurement of gas in multi-point optical absorption cells.

Claims

1. A multi-point laser multi-component gas measurement device, characterized in that: It includes a wide tunable spectrum light source, a fiber-coupled lens, a frequency modulator, a fiber beam splitter, a gas standard cell, an optical absorption cell, a photodetector and a controller. The wide-tuning spectrum light source is connected to the frequency modulator optical fiber via a fiber coupling lens, the frequency modulator is connected to the input optical fiber of the fiber beam splitter, the output end of the fiber beam splitter is connected to the gas standard cell and the optical absorption cell respectively via a transmission optical fiber, the output ports of the gas standard cell and the optical absorption cell are connected to photodetectors respectively, the photodetector is electrically connected to a controller, and the controller is electrically connected to the wide-tuning spectrum light source.

2. The laser multi-component gas measuring device according to claim 1, characterized in that: The controller includes a multi-channel data acquisition card, a processing module, a high-speed phase lock, a microwave source and a frequency multiplier. The multi-channel data acquisition card is electrically connected to the photoelectric detector, the processing module is electrically connected to the multi-channel data acquisition card, the high-speed phase lock and the microwave source respectively, the processing module is electrically connected to the wide tuning spectrum light source, and the microwave source is connected to the high-speed phase lock via a frequency multiplier.

3. The laser multi-component gas measuring device according to claim 1, characterized in that: The optical fiber beam splitter is a two-way optical fiber beam splitter, wherein one optical path is connected to the second optical fiber beam splitter, and the second optical fiber beam splitter is connected to the gas standard cell via a transmission optical fiber.

4. The laser multi-component gas measuring device according to claim 3, characterized in that: The other optical path of the two-way optical fiber splitter is connected to the third optical fiber splitter, and the third optical fiber splitter is connected to the optical absorption cell via a transmission optical fiber.

5. The laser multi-component gas measuring device according to claim 3, characterized in that: The gas standard pool includes a carbon monoxide standard pool, a methane standard pool, a carbon dioxide standard pool, an acetylene standard pool and an ethylene standard pool.

6. The laser multi-component gas measuring device according to claim 3, characterized in that: The 2-way optical fiber beam splitter is a 99 / 1 optical fiber beam splitter.

7. The laser multi-component gas measuring device according to claim 1, characterized in that: The wide tunable spectrum light source comprises a seed laser and an optical parameter module, and the optical parameter module is connected to the seed laser.

8. The laser multi-component gas measuring device according to claim 1, characterized in that: The photoelectric detector includes a single-channel photoelectric detector and a multi-channel photoelectric detector. The signal input end of the single-channel photoelectric detector is connected to the output port optical fiber of the gas standard cell, and the signal input end of the multi-channel photoelectric detector is connected to the output port optical fiber of the optical absorption cell.

9. The laser multi-component gas measuring device according to claim 4, characterized in that: An optical lens is also arranged between each optical path of the third optical fiber beam splitter and the optical absorption pool.

10. The laser multi-component gas measuring device according to claim 9, characterized in that: The length of the optical absorption cell is greater than 500 m.

Images