Infrared methane sensor

Abstract

The utility model discloses an infrared methane sensor, which belongs to the technical field of gas detection, and adopts the technical scheme that the infrared methane sensor comprises a shell, a gas chamber is arranged in the shell, one end of the gas chamber is provided with a laser, the laser comprises a transmitting module and a receiving module, and the other end of the gas chamber is provided with a light reflection structure; a plurality of vent holes communicated with the gas chamber are formed in the shell, and a waterproof breathable film covering all the vent holes is arranged on the shell. Compared with the existing gas chromatography flame ionization detector, the gas chromatography flame ionization detector disclosed by the utility model has the beneficial effects that the gas chromatography flame ionization detector is simple and easy to use, low in equipment manufacturing cost, low in operation cost and convenient and fast to manage; the sensor not only is small and portable, but also can obtain methane concentration data in real time, consumables do not need to be replaced frequently, and the use and maintenance cost is greatly reduced; the problems existing in current methane gas detection equipment are effectively solved, and the detection efficiency and practicability are improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of gas detection, and in particular relates to an infrared methane sensor. Background Art

[0002] In existing technologies, the prevention and control of gas disasters in production safety mainly relies on the accurate detection of methane concentration. However, the traditional gas chromatography flame ionization detector (GC-FID) method has problems such as complex equipment, large size, high cost, non-portability, long detection time, and the need to frequently replace the carrier gas nitrogen cylinder and chromatographic column, which makes its operating cost and maintenance difficulty high in actual application. Utility Model Content

[0003] The purpose of the utility model is to provide an infrared methane sensor.

[0004] The utility model is realized by the following measures: an infrared methane sensor, characterized in that it comprises a shell, a gas chamber is provided in the shell, a transmitting module and a receiving module are provided at one end of the gas chamber, and a light reflecting structure is provided at the other end;

[0005] The shell is provided with a plurality of vent holes communicating with the gas chamber, and the shell is provided with a waterproof breathable membrane covering all the vent holes to ensure that the gas to be measured can enter smoothly without being affected by moisture.

[0006] Furthermore, the transmitting module generally uses a light source of non-dispersive infrared light.

[0007] Furthermore, the transmitting module and the receiving module are arranged up and down, and the light reflecting structure includes a first reflecting plate corresponding to the transmitting module and a second reflecting plate corresponding to the receiving module;

[0008] Light from the transmitting module enters the receiving module via the first and second reflectors, which increases the optical path length within the gas chamber and allows for better contact with the internal gas. The first and second reflectors are generally symmetrically arranged, and their adjacent ends can be connected by a vertical plate, which can also be a reflector.

[0009] The surfaces of the receiving module and the light reflecting structure are generally plated with a reflective coating, which can improve the reflection efficiency and reduce the attenuation of light energy.

[0010] Furthermore, a mounting plate is arranged in parallel in the shell, and the gas chamber is formed between the mounting plate and the top plate of the shell.

[0011] Furthermore, a main control board is integrated inside the installation board. The main control board is a computing unit for processing and calculating the signal of the receiving module. The computing unit adopts the existing technology and will not be described in detail here.

[0012] Furthermore, the main control board also includes a port for signal interaction with the outside world, and the port uses pin-type pins to interact with the outside world.

[0013] Furthermore, the housing includes an upper housing and a lower housing connected in a detachable manner.

[0014] Furthermore, the lower housing is a rectangular base plate, and the upper housing is a rectangular cover that matches the rectangular base plate. External convex plates are provided on both sides of the rectangular base plate, and the two ends of the rectangular base plate are embedded in the rectangular cover. The bottom of the side wall of the rectangular cover is provided with a notch for the external convex plates. The external convex plates can be easily disassembled and repaired later.

[0015] Furthermore, a plurality of guide posts are symmetrically arranged on the inner wall of the shell, and a guide groove matching the guide posts is provided on the mounting plate, so as to facilitate positioning and installation of the mounting plate.

[0016] Furthermore, the ventilation holes are distributed in a matrix on the upper end surface of the shell.

[0017] Furthermore, a plurality of limiting protrusions are provided on the inner wall of the shell and below the mounting plate to ensure that there is a gap between the mounting plate and the shell.

[0018] Working principle:

[0019] The gas to be measured enters the gas chamber through the waterproof breathable membrane and vents. The transmitting module emits laser light, which, after passing through the light reflective structure, is captured by the photodiode of the receiving module. The receiving module converts the received optical signal into an electrical signal and outputs it. During this process, the computing unit receives the electrical signal in real time, processes it, and calculates the methane concentration. The calculated methane concentration can be communicated to the outside world via the communication port.

[0020] The beneficial effects of the technical solution provided by the embodiment of the present utility model are as follows: compared with the existing gas chromatography flame ionization detector, it is simple and easy to use, has low equipment manufacturing cost, low operating cost, and convenient management; the sensor is not only compact and portable, but also can obtain methane concentration data in real time, without the need for frequent replacement of consumables, greatly reducing the cost of use and maintenance; it effectively solves the problems existing in current methane gas detection equipment, improves detection efficiency and practicality, and is conducive to its wide application in various industrial production environments, especially for the prevention and control of gas disasters in coal mines and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solution of the present invention, a brief introduction will be given below to the drawings used in the embodiments. Obviously, the drawings listed 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.

[0022] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the utility model;

[0023] Figure 2 It is a schematic diagram of the structure with the waterproof breathable membrane removed;

[0024] Figure 3 It is a schematic diagram of the structure with the lower shell removed;

[0025] Figure 4 It is a schematic diagram of the structure with the upper shell removed;

[0026] Figure 5 It is a schematic diagram of the structure inside the shell;

[0027] Figure 6 It is a light path diagram of an embodiment of the utility model.

[0028] Figure 7 This is the circuit diagram of the transmitter module;

[0029] Figure 8 This is the circuit diagram of the receiving module;

[0030] Figure 9 This is the wiring diagram of the laser;

[0031] Figure 10 It is the power circuit.

[0032] In the accompanying drawings, the components represented by each number are listed as follows: 1. Shell; 2. Pin; 3. Gas chamber; 4. Light reflection structure; 5. Mounting plate; 6. Vent; 7. Waterproof and breathable membrane; 101. Lower shell; 10101. Outer convex plate; 102. Upper shell; 10201. Guide column; 10202. Notch; 10203. Limiting protrusion; 301. Transmitting module; 302. Receiving module. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. Of course, the specific embodiments described here are only used to explain the present invention and are not intended to limit the present invention.

[0034] See also Figures 1-6An infrared methane sensor, characterized in that it includes a housing 1, a gas chamber 3 is provided in the housing 1, a transmitting module 301 and a receiving module 302 are provided at one end of the gas chamber 3, and a light reflecting structure 4 is provided at the other end;

[0035] The housing 1 is provided with a plurality of vent holes 6 communicating with the gas chamber 3 . The housing 1 is provided with a waterproof breathable membrane 7 covering all the vent holes 6 to ensure that the gas to be measured can enter smoothly without being affected by moisture.

[0036] The transmitting module 301 generally uses a non-dispersive infrared light source.

[0037] The transmitting module 301 and the receiving module 302 are arranged in an upper and lower manner, and the light reflecting structure 4 includes a first reflecting plate corresponding to the transmitting module 301 and a second reflecting plate corresponding to the receiving module 302;

[0038] The light from the transmitting module 301 enters the receiving module 302 through the first and second reflective plates, which can increase the optical path in the gas chamber 3 and allow it to better contact the internal gas. The first and second reflective plates are generally symmetrically arranged.

[0039] The surfaces of the receiving module 302 and the light reflecting structure 4 are generally plated with a reflective coating, which can increase the reflection efficiency and reduce the attenuation of light energy.

[0040] A mounting plate 5 is arranged parallel to the housing 1 , and a gas chamber 3 is formed between the mounting plate 5 and the top plate of the housing 1 .

[0041] A main control board is integrated inside the mounting plate 5 . The main control board is a computing unit for processing and calculating the signal of the receiving module 302 . The computing unit adopts the existing technology and will not be described in detail here.

[0042] The main control board also includes a port for signal interaction with the outside world. The port uses a pin 2 type pin to interact with the outside world.

[0043] The housing 1 includes an upper housing 102 and a lower housing 101 that are detachably connected.

[0044] The lower shell 101 is a rectangular base plate, and the upper shell 102 is a rectangular cover that matches the rectangular base plate. Outer convex plates 10101 are set on both sides of the rectangular base plate, and the two ends of the rectangular base plate are embedded in the rectangular cover. A notch 10202 for placing the outer convex plate 10101 is set at the bottom of the side wall of the rectangular cover.

[0045] A plurality of guide posts 10201 are symmetrically arranged on the inner wall of the housing 1 , and a guide groove matching the guide posts 10201 is provided on the mounting plate 5 .

[0046] The ventilation holes 6 are distributed in a matrix on the upper end surface of the housing 1 .

[0047] A plurality of limiting protrusions 10203 are provided on the inner wall of the shell and below the mounting plate 5 .

[0048] This embodiment, as an infrared methane sensor, can detect methane concentration, and other structural features not mentioned can be realized by using existing technologies.

[0049] Working principle:

[0050] The gas to be measured enters the gas chamber through the waterproof, breathable membrane 7 and the vent 6. Transmitter module 301 emits laser light, which, after passing through light-reflecting structure 4, is captured by the photodiode of receiver module 302. Receiver module 302 converts the received optical signal into an electrical signal and outputs it. During this process, the computing unit receives and processes the electrical signal in real time, calculating the methane concentration. This calculated methane concentration can be communicated to the outside world via the communication port.

[0051] Example 2:

[0052] See also Figures 1-10 On the basis of the first embodiment, the transmitting module 301 includes an operational amplifier, and the single chip microcomputer uses the DAC function to control the voltage of the laser LED-pin through the operational amplifier voltage follower, thereby controlling the on-off operation of the laser.

[0053] The operational amplifier uses the LMV358MR operational amplifier, in which the non-inverting input of the operational amplifier is connected to the microcontroller, the inverting input is connected to the emitter of the transistor and resistor R6, and then grounded after resistor R6. The output of the operational amplifier is connected to the base of the transistor, and the collector of the transistor is connected to the LED-pin of the laser. Pin 8 of the operational amplifier is connected to the power supply and capacitor C19, one end of capacitor C19 is grounded, and pin 4 of the operational amplifier is grounded.

[0054] Receiving module 302 includes two stages of operational amplifiers. The inverting input of the first stage operational amplifier is connected to the OUT pin of the photodiode, the non-inverting input of the first stage operational amplifier is grounded, the output of the first stage operational amplifier is connected to capacitor C18, and capacitor C16 and resistor R11 are connected in parallel between the inverting input and output. The inverting input of the second stage operational amplifier is connected to resistor R13 and grounded, the non-inverting input of the second stage operational amplifier is connected to capacitor C18, the output of the second stage operational amplifier is connected to the microcontroller, and capacitor C17 and resistor R12 are connected in parallel between the inverting input and output. The first and second stage operational amplifiers generally use TLV2372IDR amplifiers. The OUT pin of the photodiode is connected to pin 2 of the TLV2372IDR operational amplifier, and the voltage after secondary amplification is collected by the microcontroller ADC.

[0055] In addition, if Figure 4Pins 6 and 8 are connected to the receiving photodiode, while pins 1, 2, 3, 4, 5, and 7 are connected to the laser. The laser is connected to the MCU's IO port via pin 3, sending the temperature analog value to the MCU. After the MCU obtains and processes the temperature analog value, it generates PWM control with different duty cycles through the MCU's IO port PWM pin, controlling the laser's pin 5, thereby achieving a constant operating temperature for the laser.

[0056] The above are only preferred embodiments of the present invention and are 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. An infrared methane sensor, characterized in that: It comprises a shell, a gas chamber is arranged in the shell, a laser is arranged at one end of the gas chamber, the laser comprises a transmitting module and a receiving module, and a light reflecting structure is arranged at the other end of the gas chamber; a plurality of ventilation holes connected with the gas chamber are opened on the shell, and a waterproof breathable membrane covering all the ventilation holes is arranged on the shell.

2. The infrared methane sensor according to claim 1, characterized in that: The transmitting module and the receiving module are arranged up and down, and the light reflecting structure includes a first reflecting plate corresponding to the transmitting module and a second reflecting plate corresponding to the receiving module; the light of the transmitting module enters the receiving module through the first reflecting plate and the second reflecting plate.

3. The infrared methane sensor according to claim 1, characterized in that: A mounting plate is arranged in parallel in the shell, and the gas chamber is formed between the mounting plate and the top plate of the shell.

4. The infrared methane sensor according to claim 3, characterized in that: A main control board is integrated inside the installation board.

5. The infrared methane sensor according to claim 4, characterized in that: The main control board also includes a port for signal interaction with the outside world.

6. The infrared methane sensor according to claim 1, characterized in that: The housing comprises an upper housing and a lower housing which are connected in a detachable manner.

7. The infrared methane sensor according to claim 6, characterized in that: The lower shell is a rectangular bottom plate, the upper shell is a rectangular cover matching the rectangular bottom plate, outer convex plates are arranged on both sides of the rectangular bottom plate, the two ends of the rectangular bottom plate are embedded in the rectangular cover, and a notch for placing the outer convex plate is arranged at the bottom of the side wall of the rectangular cover.

8. The infrared methane sensor according to claim 3, characterized in that: A plurality of guide posts are symmetrically arranged on the inner wall of the shell, and a guide groove matching the guide posts is arranged on the mounting plate.

9. The infrared methane sensor according to claim 3, characterized in that: The ventilation holes are distributed in a matrix on the upper end surface of the shell.

10. The infrared methane sensor according to claim 3, characterized in that: A plurality of limiting protrusions are arranged on the inner wall of the shell and below the mounting plate.

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