CN108375555A - Optical fiber methane sensing module, optical fiber multiple spot photo-electric methane transducer and system - Google Patents

Abstract

The invention relates to an optical fiber methane sensing module, an optical fiber multi-point photoelectric methane sensor and a system. The system includes an optical fiber multi-point photoelectric methane sensor, and the sensor includes a VCSEL laser, an optical fiber methane sensing module, an optical fiber beam splitter, and a Signal processing device for signal transmission and reception. The system is a long-distance, multi-channel (or multi-detection point) methane sensing system that can be implemented by optical fiber connection. The signal processing device for transmitting and receiving optical signals is connected to the optical fiber splitting device. The optical signal emitted by the signal processing device is distributed to each optical fiber channel through the optical fiber splitting device and transmitted to the corresponding optical fiber methane sensing modules arranged at different detection points. The invention not only increases the integration degree of the detection system, but also expands the coverage range that can be detected, improves the adaptability of the system in different occasions, and reduces the production and processing cost at the same time.

Description

Optical fiber methane sensing module, optical fiber multi-point photoelectric methane sensor and system

technical field

The invention belongs to the technical field of laser spectrum methane sensors, and in particular relates to an optical fiber methane sensing module, an optical fiber multi-point photoelectric methane sensor and a system.

Background technique

In recent years, with the continuous advancement of China's urbanization process, people's requirements for living environment and production safety have been increasing. Therefore, people's demand for monitoring various potential hazards is also increasing. For example, in urban underground pipe corridors, underground waterways, a large number of coal dumps, garbage dumps and other places, there will be random occurrence of methane and gas, which constitutes a potential source of danger. It has become a growing market demand to be able to conduct large-scale, effective and real-time detection of these hazards.

Among the many methane detection technologies, the photoelectric technology based on the principle of infrared laser spectrum absorption to measure the composition and concentration of methane has excellent characteristics such as large concentration range, high measurement accuracy, and no need for long calibration time, so that the laser spectrum methane sensor can be widely used Applied to different production processes and safety precautions.

Optical spectral absorption methane sensors include infrared spectral absorption type and infrared laser spectral absorption type. Since different methane has different characteristic spectral absorption peaks in the infrared region, when the measured methane passes through infrared light or infrared laser, its light intensity will be modulated by the measured methane at the characteristic spectral absorption peak, and the amplitude of the light intensity modulation is the same as the measured methane It is directly proportional to the concentration of methane, so by detecting and analyzing the light intensity change of the infrared absorption peak, the concentration of the measured methane can be detected.

Relatively speaking, the optical spectral absorption methane sensor has a high ability to resist methane cross-interference, especially the laser spectral methane sensor has a good anti-methane cross-interference ability. Combined with modern electronic processing technology, these sensors can realize the functions of continuous testing and automatic operation of the measured methane; they have the characteristics of automatic calibration, high measurement accuracy and fast response time. This type of sensor can be used in many industrial production processes, such as petrochemical, mining, semiconductor industry and other industrial and mining production detection and alarm, such as hydrogen sulfide, oxygen, carbon monoxide, carbon dioxide, chlorine, methane and combustible hydrocarbons are the main detection methane . Detection of items such as phosphorus, arsenic, and silane are major applications in the semiconductor industry. These sensors can also be used for security detection and alarm in public and home environments. It is mainly used in households to detect leaks of gas, natural gas and liquefied petroleum gas and to provide safety reminders and alarms.

However, generally single-point methane sensors detect methane in the space near the sensor, and for large-area, long-distance actual measurement scenarios, it is required to form a quasi-distributed multi- Channel or multi-point photoelectric methane sensor system. This greatly increases the complexity of the measurement system and increases the power consumption of the entire system, resulting in increased production and maintenance costs of the system. Therefore, it can meet the monitoring and control requirements of multi-point and multi-parameter gases in gas detection and industrial process control, reduce the cost of the whole system, simplify the system light source and signal detection and processing system, and enhance the reliability of the system. solved problem.

To sum up, in the prior art, how to detect methane gas in a large-area and long-distance measurement environment while satisfying the problems of low cost and high reliability still lacks an effective solution.

Contents of the invention

Aiming at the deficiencies in the prior art and solving the problem of how to detect methane gas in a large-area and long-distance measurement environment in the prior art while satisfying low cost and high reliability, the present invention provides an optical fiber methane detector. Sensing module, optical fiber multi-point photoelectric methane sensor and system. The multi-channel optical fiber methane sensing system not only increases the integration of the detection system, but also expands the coverage that can be detected, and improves the system's use in different occasions. Adaptability, while reducing production and processing costs.

The first object of the present invention is to provide an optical fiber methane sensing module.

In order to achieve the above object, the present invention adopts the following technical scheme:

An optical fiber methane sensing module, comprising:

A housing with accommodating space, inside the housing is provided with an incoming optical fiber and an outgoing optical fiber, at least two gas sensing air chambers parallel to each other between the incoming optical fiber and the outgoing optical fiber, the gas sensing air chambers Through the optical fiber connection, according to the transmission direction of the optical signal, the gas chamber incident light conversion unit and the gas chamber exit light conversion unit are respectively arranged before and after the gas sensing gas chamber;

The gas chamber incident light conversion unit converts the outgoing light beam of the optical fiber into a parallel light beam and injects it into the gas sensing gas chamber, and the gas chamber outgoing light conversion unit couples the outgoing light beam of the gas sensing gas chamber into the connection The optical fiber or the outgoing optical fiber of the gas sensing gas chamber.

As a further preferred solution, the incident light conversion unit of the air chamber adopts a fiber optic collimator lens.

As a further preferred solution, the light conversion unit emitted from the air chamber adopts a fiber optic focusing lens.

As a further preferred solution, several air holes are arranged on the side of the gas sensing chamber, and a metal filter is arranged on the air holes.

As a further preferred solution, the housing includes a housing, and the upper and lower covers of the housing are respectively provided with an upper cover and a lower cover to form a structure with accommodating space, the upper cover is provided with a through hole, and the connecting optical fiber and the connecting optical fiber The optical fiber passes through the through hole, a calibration nozzle with a through hole is arranged on the lower cover, a powder metallurgy filter is arranged above the calibration nozzle, and a plug is arranged between the casing and the lower cover.

As a further preferred solution, a replaceable metal filter screen is arranged inside the upper cover.

As a further preferred solution, a reference air chamber with a temperature and pressure sensor is arranged in the housing.

The second object of the present invention is to provide an optical fiber multi-point photoelectric methane sensor, which adopts the above optical fiber methane sensing module.

In order to achieve the above object, the present invention adopts the following technical scheme:

An optical fiber multi-point photoelectric methane sensor, comprising: several optical fiber methane sensing modules, an optical fiber splitting device, and a signal processing device for transmitting and receiving optical signals; the signal processing device for transmitting and receiving optical signals is connected to the optical fiber splitting device The optical signal emitted by the optical signal transmitting and receiving signal processing device is distributed to each optical fiber channel through the optical fiber splitting device and transmitted to the corresponding optical fiber methane sensing module arranged at different detection points.

As a further preferred solution, the optical fiber splitting device adopts a 1XN optical fiber splitter, a CWDM optical splitter or multiple fiber couplers.

As a further preferred solution, the splitting ratio of the optical fiber splitting device is evenly distributed among the channels;

Or adjust the light splitting ratio distributed between each channel according to the distance from the detection point where the optical fiber methane sensing module is located, and the light intensity of the optical signal distributed by the channel is proportional to the length of the channel.

As a further preferred solution, the signal processing device for transmitting and receiving optical signals includes a microprocessor module, the microprocessor module is respectively connected to the light source module and the optical signal acquisition module through the communication module, the microprocessor module, the communication module , the light source module and the optical signal acquisition module are respectively connected to the power module;

The microprocessor module is used for tuning the light source signal in the light source module and processing the measurement signal in the light signal acquisition module;

The communication module is used to transmit control instructions of the microprocessor module and measurement signals in the optical signal acquisition module.

As a further preferred solution, when the environmental conditions of the optical fiber methane sensing module are the same as or close to the environmental conditions of the optical signal transmitting and receiving signal processing device, the microprocessor module receives the light source module The temperature and pressure information is used to compensate the measured gas.

As a further preferred solution, the light source module uses a VCSEL laser.

The third object of the present invention is to provide an optical fiber multi-point photoelectric methane sensor system, which adopts the above-mentioned optical fiber multi-point photoelectric methane sensor.

Beneficial effects of the present invention:

1. A kind of optical fiber methane sensor module, optical fiber multi-point photoelectric methane sensor and system described in the present invention adopts an uncharged methane sensor module, so that each module can be placed in any potentially dangerous area, such as high Electromagnetic radiation areas, flammable and explosive areas, areas with potential hazards to human body, etc.

2. An optical fiber methane sensing module, optical fiber multi-point photoelectric methane sensor and system described in the invention adopts a passive optical fiber network structure, and each methane sensor module is connected by an optical fiber, so that each measurement point can be flexibly set , and placed arbitrarily according to the distance of the measurement point.

3. A kind of optical fiber methane sensing module, optical fiber multi-point photoelectric methane sensor and system described in the invention adopts a series design of two or more gas chambers in the optical fiber methane sensing module of the methane sensor, which not only reduces the The volume of the sensor also increases the absorption optical path, which is conducive to improving the detection signal-to-noise ratio and measurement accuracy and measurement sensitivity.

4. The optical fiber methane sensing module, optical fiber multi-point photoelectric methane sensor and system described in the invention use VCSEL lasers to realize the fiber multi-point photoelectric methane sensing measurement without increasing the power consumption of the system .

Description of drawings

Fig. 1 is the structural representation of the optical fiber methane sensing module of the present invention;

Fig. 2 is the shell structure schematic diagram of the optical fiber methane sensing module of the present invention;

Fig. 3 is a schematic structural view of the beam splitting device of the present invention;

4 is a schematic diagram of a signal processing device for optical signal transmission and reception of the present invention;

Fig. 5 is a schematic diagram of the system of the present invention.

Detailed ways:

Below in conjunction with accompanying drawing and embodiment the present invention will be further described:

It should be pointed out that the following detailed description is exemplary and intended to provide further explanation to the present application. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It should be noted that the terminology used here is only for describing specific implementations, and is not intended to limit the exemplary implementations according to the present application. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural, and it should also be understood that when the terms "comprising" and/or "comprising" are used in this specification, they mean There are features, steps, operations, means, components and/or combinations thereof.

As mentioned in the background, if the existing single-point laser methane sensor is used to form a large-scale, long-distance methane detection system, the complexity of the measurement system will be greatly increased, and the power consumption of the entire system will be increased. As a result, the system The production cost and maintenance cost increase.

Aiming at the deficiencies in the prior art and solving the problem of how to detect methane gas in a large-area and long-distance measurement environment in the prior art while satisfying low cost and high reliability, the present invention provides an optical fiber methane detector. Sensing module, optical fiber multi-point photoelectric methane sensor and system. The multi-channel optical fiber methane sensing system not only increases the integration of the detection system, but also expands the coverage that can be detected, and improves the system's use in different occasions. Adaptability, while reducing production and processing costs.

Example 1:

The purpose of Embodiment 1 is to provide an optical fiber methane sensing module.

In order to achieve the above object, the present invention adopts the following technical scheme:

As shown in Figure 1 and Figure 2,

An optical fiber methane sensing module, comprising:

A housing with accommodating space, inside the housing is provided with an incoming optical fiber and an outgoing optical fiber, at least two gas sensing air chambers parallel to each other between the incoming optical fiber and the outgoing optical fiber, the gas sensing air chambers Through the optical fiber connection, according to the transmission direction of the optical signal, the gas chamber incident light conversion unit and the gas chamber exit light conversion unit are respectively arranged before and after the gas sensing gas chamber;

The gas chamber incident light conversion unit converts the outgoing light beam of the optical fiber into a parallel light beam and injects it into the gas sensing gas chamber, and the gas chamber outgoing light conversion unit couples the outgoing light beam of the gas sensing gas chamber into the connection The optical fiber or the outgoing optical fiber of the gas sensing gas chamber.

In this embodiment, the incident light conversion unit of the gas chamber adopts a fiber optic collimator lens. The light conversion unit emitted by the air chamber adopts a fiber optic focusing lens.

For example, the optical fiber methane sensing module with two gas sensing gas chambers as shown in Figure 1 is provided with an access optical fiber, a first optical fiber parallel light lens, a first gas sensing gas chamber, The first optical fiber focusing lens, the gas sensing air chamber connection optical fiber, the second optical fiber parallel light lens, the second gas sensing air chamber, the second optical fiber focusing lens and the outgoing optical fiber, the optical fiber fusion splicer for the above optical fiber devices according to the pre-designed The optical paths are fused together to form a complete gas detection optical path.

This embodiment can be further improved, the first gas sensing chamber and the second gas sensing chamber are provided with a number of ventilation holes on the sides, and metal filter screens are arranged on the ventilation holes. The methane to be measured diffuses into the gas sensing chamber through a vent hole provided with a metal filter screen.

In this embodiment, the access optical fiber may be a single-mode optical fiber or a multi-mode optical fiber; the first optical fiber parallel lens converts the output beam of the access optical fiber into a parallel beam and injects it into the first gas sensor The gas chamber; the laser beam emitted from the first gas sensing chamber is coupled into the gas sensing chamber connecting optical fiber by the first fiber focusing lens; the outgoing laser beam from the gas sensing chamber connecting optical fiber The laser beam is turned into a parallel beam by the second optical fiber parallel optical lens and enters the second gas sensing gas chamber; the laser beam emitted from the second gas sensing gas chamber is transmitted by the second optical fiber The focusing lens is coupled into the outgoing optical fiber; the laser beam becomes a laser beam modulated by the measured gas through the above process. Then, the outgoing optical fiber transmits the laser beam modulated by the measured gas back to the signal processing device for transmitting and receiving optical signals.

In the optical fiber methane sensing module, the purpose of adopting the double gas sensing gas chamber is to increase the optical path of the sensing gas chamber, increase the test sensitivity and improve the test accuracy. Due to the adoption of the design of connecting the gas sensing gas chamber to the optical fiber, the two gas chambers can be installed in parallel, thereby reducing the volume of the entire optical fiber methane sensing module. Under the requirement of high precision in some special measurements, the present invention adopts the design of the multi-gas chamber (greater than two gas chambers, such as three gas chambers, four gas chambers, etc., in series) design, which can be achieved without increasing the transmission rate. Under the condition of reducing the volume of the sensing module, the measurement accuracy of gas detection is further improved. At this time, factors that need to be considered are fabrication complexity, optical loss, and fabrication cost.

In this embodiment, all the optical fiber devices in the optical fiber methane sensing module are installed in a special housing with accommodating space, and all the optical fiber devices are installed in a specially designed methane sensing module so as to control the optical fiber bend, and protect the fiber from being scratched during installation. After all the optical fiber components are successfully installed in the module, sealant is used to fix and seal the optical fiber components according to the design scheme.

It should be noted that the shape of the housing of the optical fiber methane sensing module can be adjusted according to the requirements of customers and application scenarios, including but not limited to cylindrical, elliptical cylindrical, and rectangular cylindrical.

As shown in Figure 2, in the optical fiber methane sensing module, in addition to the access optical fiber, the first optical fiber parallel light lens, the first gas sensing gas chamber, the first optical fiber focusing lens, the gas sensing gas chamber connecting optical fiber, The second optical fiber parallel optical lens, the second gas sensing gas chamber, the second optical fiber focusing lens and the mechanical mechanism other than the outgoing optical fiber are composed of an upper cover, a housing, a temperature and pressure sensor, a powder metallurgy filter, a plug, and a lower cover It is composed of components such as a calibration nozzle, the shell includes a housing, and the housing is provided with an upper cover and a lower cover respectively to form a structure with accommodating space, the upper cover is provided with a through hole, and the access optical fiber and the connection The outgoing optical fiber passes through the through hole, a calibration nozzle with a through hole is arranged on the lower cover, a powder metallurgy filter is arranged above the calibration nozzle, and a plug is arranged between the housing and the lower cover.

This embodiment can be further improved, and a replaceable metal filter screen is arranged in the upper cover. It is used to prevent dust, impurities, etc. from entering the absorption cell and contaminating the optical components in the optical path.

This embodiment can be further improved, and a reference air chamber with a temperature and pressure sensor is arranged in the housing. When the environmental conditions of the optical fiber methane sensing module are the same as or close to the environmental conditions of the optical signal transmitting and receiving signal processing device, the microprocessor module receives the temperature and pressure of the optical fiber methane sensing module The pressure and temperature information sent by the sensor is used for compensation of the measured gas.

Example 2:

The purpose of Embodiment 2 is to provide an optical fiber multi-point photoelectric methane sensor, which adopts the above optical fiber methane sensing module.

In order to achieve the above object, the present invention adopts the following technical scheme:

As shown in Figure 5,

A fiber optic multi-point photoelectric methane sensor, comprising: several fiber optic methane sensing modules (fiber optic methane sensing module 1···fiber optic methane sensing module N), fiber optic beam splitting device, and signal processing for optical signal transmission and reception device; the optical signal transmitting and receiving signal processing device is connected to the optical fiber splitting device, the optical signal emitted by the optical signal transmitting and receiving signal processing device is distributed to each fiber channel through the optical fiber splitting device and transmitted to Correspondingly, the optical fiber methane sensing modules are arranged at different detection points.

In this embodiment, the optical fiber splitting device adopts a 1XN optical fiber splitter, a CWDM optical splitter or multiple optical fiber couplers, as shown in FIG. 3 . The splitting ratio of the optical fiber beam splitting device is evenly distributed among the channels; or the splitting ratio distributed among the channels is adjusted according to the distance between the detection point where the optical fiber methane sensing module is located, and the optical signal light distributed by the channel Strongly proportional to the channel length.

It should be noted that the splitting ratio of the optical fiber splitting device is usually evenly distributed among the channels. For some special application requirements, the splitting ratio of the optical fiber splitting device can be adjusted according to the specific test environment. Generally speaking, for a channel used at a detection point that needs to be measured at a relatively long distance, due to the long length of the optical fiber of this channel, the loss of light energy during transmission is relatively large, so the allocated light intensity for this channel can be larger.

As shown in Figure 4, the signal processing device for transmitting and receiving optical signals includes a microprocessor module, and the microprocessor module is respectively connected to the light source module and the optical signal acquisition module through the communication module, and the microprocessor module, communication module , the light source module and the optical signal acquisition module are respectively connected to the power module;

The microprocessor module is used for tuning the light source signal in the light source module and processing the measurement signal in the light signal acquisition module;

The communication module is used to transmit control instructions of the microprocessor module and measurement signals in the optical signal acquisition module.

In this embodiment, the light source module uses a VCSEL laser. The optical signal acquisition module uses a photodetector. The device for transmitting and receiving optical signals is a near-infrared vertical cavity surface emitting laser (VCSEL) as its light source module, and the tuning circuit converts the tuning signal into a tuned optical signal through the VCSEL laser and sends it to the optical fiber branch. The access fiber of the beam device; the VCSEL laser is tuned by the drive circuit and emits a tuned beam, which is coupled to a 1XN fiber beam splitter (N can be 2, 4, 6, ... etc.). Each of the N channels of fiber optic channels should be connected to an optical fiber interface, so as to form a transmitting end of the N channels of measurement channels.

The light intensity of the tuned optical signal is distributed to each channel through the optical fiber splitting device and transmitted to the corresponding methane sensing module. The laser light modulated by the measured gas concentration will form a modulated light beam and be transmitted back to the signal processing device through the return optical fiber. The modulated light beam transmitted back from each channel is received by a photodetector and processed by the signal processing circuit in the microprocessor module to obtain the methane concentration test result of the channel. A schematic diagram of the device for transmitting and receiving optical signals is shown in FIG. 4 .

In the VCSEL laser optical signal transmitting and receiving processing device, each channel has another optical fiber interface, which can be used to connect the outgoing optical fiber of the optical fiber methane sensing module. The optical fiber in the optical fiber interface is connected to a photodetector. The optical signal transmitted back from the optical fiber methane sensing module is converted into an electronic signal by the photodetector, and the signal is amplified, A/D converted, and then sent to the microprocessor module for processing.

In the optical fiber methane sensing module, there is an access optical fiber that transmits the light beam of the VCSEL to the optical fiber methane sensing module, and the other output optical fiber transmits the light beam tuned by methane in the optical fiber methane sensing module back to the signal processing device .

Since the optical fiber methane sensing module and the signal processing device can be connected through an optical fiber port, the distance from the optical fiber methane sensing module to the signal processing device can be adjusted by adjusting the length of the connecting line. Generally speaking, the shortest distance from the optical fiber methane sensing module to the signal processing device is 1 meter, and the longest distance is 150 meters.

The location of the optical fiber methane sensing module can be designed according to actual application requirements. For example, in the detection of the coal mining field, it can be found between the coal mining face frame, behind the working face frame, the nose, the tail corner of the machine, the top of the loader, the return air chute of the coal mining face, the upper corner, and the mining face. Optical fiber methane sensing modules are placed at all locations where electrical equipment is installed on the coal face; or in the application of pipe gallery detection, optical fiber methane sensing modules are placed at certain distances along the direction of the pipe gallery as required.

This embodiment can be further improved by setting a temperature and pressure sensor next to the reference gas chamber. When the environmental conditions of the optical fiber methane sensing module are the same as or close to the environmental conditions of the signal processing device for transmitting and receiving the optical signal, the microprocessor module receives the pressure and temperature sent by the temperature and pressure sensor Information for compensation of the measured gas.

Example 3:

The purpose of Embodiment 3 is to provide a fiber optic multi-point photoelectric methane sensor system. Based on the above-mentioned Embodiment 1 and Embodiment 2, the above-mentioned fiber optic multi-point photoelectric methane sensor is used, as shown in FIG. 5 .

Beneficial effects of the present invention:

1. A kind of optical fiber methane sensor module, optical fiber multi-point photoelectric methane sensor and system described in the present invention adopts an uncharged intrinsically safe methane sensor module, so that each module can be placed in any potentially dangerous area, For example, areas with high electromagnetic radiation, flammable and explosive areas, areas with potential hazards to human body, etc.

2. An optical fiber methane sensing module, optical fiber multi-point photoelectric methane sensor and system described in the invention adopts a passive optical fiber network structure, and each methane sensor module is connected by an optical fiber, so that each measurement point can be flexibly set , and placed arbitrarily according to the distance of the measurement point.

3. A kind of optical fiber methane sensing module, optical fiber multi-point photoelectric methane sensor and system described in the invention adopts a series design of two or more gas chambers in the optical fiber methane sensing module of the methane sensor, which not only reduces the The volume of the sensor also increases the absorption optical path, which is conducive to improving the detection signal-to-noise ratio and measurement accuracy and measurement sensitivity.

4. The optical fiber methane sensing module, optical fiber multi-point photoelectric methane sensor and system described in the invention use VCSEL lasers to realize the fiber multi-point photoelectric methane sensing measurement without increasing the power consumption of the system .

The above descriptions are only preferred embodiments of the present application, and are not intended to limit the present application. For those skilled in the art, various modifications and changes may be made to the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included within the protection scope of this application. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. a kind of optical fiber methane sensing module, which is characterized in that including：

Shell with accommodation space is equipped with incoming fiber optic and picks out optical fiber inside the housing, the incoming fiber optic and picks out light At least two gas sensing gas chamber being mutually parallel between fibre is connected between the gas sensing gas chamber by optical fiber, is believed according to light It is single that the gentle room emergent light conversion of gas chamber incidence optical conversion element is respectively set before and after the gas sensing gas chamber in number transmission direction Member；

The outgoing beam of optical fiber is become collimated light beam and injects the gas sensing gas chamber by the gas chamber incidence optical conversion element, The outgoing beam of the gas sensing gas chamber is coupled into the connection gas sensing gas chamber by the gas chamber outgoing optical conversion element Optical fiber or pick out optical fiber.

2. a kind of optical fiber methane sensing module according to claim 1, which is characterized in that the gas chamber incident light conversion is single Member uses optical fiber parallel light lens.Or

The gas chamber outgoing optical conversion element uses fiber focus lens.

3. a kind of optical fiber methane sensing module according to claim 1, which is characterized in that the gas sensing gas chamber side Several ventholes are set, metal screen is set on the venthole.

Scheme as a further preference, the shell include shell, and upper cover and lower cover is respectively set up and down in the shell, are formed Structure with accommodation space, is arranged through-hole on the upper lid, the incoming fiber optic and picks out optical fiber via the through-hole, under described The calibration mouth for being provided with through-hole is covered, powder metallurgy strainer is set above the calibration mouth, is set between the shell and lower cover Set plug.

4. a kind of optical fiber methane sensing module according to claim 1, which is characterized in that setting can be set in the upper cover The metal screen changed.

Or, being provided with the reference gas chamber of temperature and pressure transmitter in the shell.

5. a kind of optical fiber multiple spot photo-electric methane transducer is passed based on a kind of optical fiber methane of claim 1-4 any one of them Feel module, which is characterized in that including：It several optical fiber methane sensing modules, fiber beam splitting device and optical signal launch and connects The signal processing apparatus received；The optical signal launch connects fiber beam splitting device, the light letter with the signal processing apparatus of receiving Number transmitting and receive signal processing apparatus transmitting optical signal by the fiber beam splitting device be assigned to each optical fiber lead to Road is simultaneously transmitted to the corresponding optical fiber methane sensing module for being set to different test points.

6. a kind of optical fiber multiple spot photo-electric methane transducer according to claim 5, which is characterized in that the fiber beam splitting Device uses a 1XN fiber splitter, a CWDM optical splitter or multiple fiber couplers.

Or, the light splitting ratio of the fiber beam splitting device is evenly distributed between each channel；

Or the light splitting between each channel is distributed according to the distance between test point adjustment where optical fiber methane sensing module Ratio, the optical signal light intensity that channel is distributed are directly proportional to the passage length.

7. a kind of optical fiber multiple spot photo-electric methane transducer according to claim 5, which is characterized in that the optical signal hair The signal processing apparatus penetrated and received includes microprocessor module, and the microprocessor module is separately connected light by communication module Source module and light signal collection module, the microprocessor module, communication module, light source module and light signal collection module difference It is connected with power module；

The microprocessor module is for tuning light source die light signal in the block and handling the light signal collection module In measuring signal；

The communication module is for transmitting the control instruction of the microprocessor module and the light signal collection mould survey in the block Measure signal.

8. a kind of optical fiber multiple spot photo-electric methane transducer according to claim 7, which is characterized in that in the optical fiber first The environmental condition of alkane sensing module is as the environmental condition of the signal processing apparatus of receiving or close with the optical signal launch In the case of, the microprocessor module receive the optical fiber methane sensing module temperature and pressure transmitter send pressure and Temperature information, for the compensation to being tested gas.

9. a kind of optical fiber multiple spot photo-electric methane transducer according to claim 7, which is characterized in that the light source module Using VCSEL lasers.

10. a kind of optical fiber multiple spot photo-electric methane transducer system, which is characterized in that described in claim any one of 5-9 A kind of optical fiber multiple spot photo-electric methane transducer.