CN202210074U - Portable infrared absorption type methane detector - Google Patents

Abstract

A portable infrared absorption methane detector relates to a methane detector, which solves the problems of low detection accuracy, narrow detection range, cumbersome adjustment and poor portability of existing methane detectors. It is powered by a lithium battery, and a modulation signal is generated by a control circuit to control a light source modulation circuit to generate a light source modulation signal required by a methane sensor; the methane concentration acquisition signal output end of the methane sensor is connected to the acquisition signal input end of the signal conditioning circuit; the conditioning signal output end of the signal conditioning circuit is connected to the analog signal input end of the A/D conversion circuit; the digital signal output end of the A/D conversion circuit is connected to the digital signal input end of the control circuit. The utility model is suitable for methane concentration detection.

Description

Portable infrared absorption methane detector

technical field

The utility model relates to a methane detector.

Background technique

In mining production, the lower explosive limit of methane content is 5.3%. Accurate detection of methane gas content and timely alarm play a vital role in the safe operation of industrial mines and personal safety. At present, the most commonly used methane detectors in my country's coal mines are carrier catalytic combustion type, optical interference type, and thermal conductivity type. The detection accuracy is low, the detection range is narrow, the adjustment is frequent, and the operation is cumbersome. resulting in accidents. Therefore, it is necessary to develop a reliable, economical and simple methane concentration detection and alarm instrument.

Utility model content

The utility model aims to solve the problems of low detection accuracy, narrow detection range, cumbersome adjustment and poor portability of the existing methane detector, thereby providing a portable infrared absorption methane detector.

A portable infrared absorption methane detector, which includes a control circuit, a light source modulation circuit, a methane sensor, a signal conditioning circuit, an A/D conversion circuit and a power supply circuit, the control circuit generates a modulation signal, and the light source modulation circuit generates the methane sensor required light source modulation signal; the methane concentration acquisition signal output end of the methane sensor is connected to the acquisition signal input end of the signal conditioning circuit; the conditioning signal output end of the signal conditioning circuit is connected to the analog signal input end of the A/D conversion circuit; The digital signal output end of the A/D conversion circuit is connected with the digital signal input end of the control circuit; the power supply circuit is used to provide working power for the detector.

The utility model has high detection precision, wide detection range, simple adjustment process, and the utility model can adopt a lithium battery for power supply, and has good portability.

Description of drawings

Fig. 1 is the structural representation of the utility model.

Detailed ways

Specific Embodiments 1. This specific embodiment is described in conjunction with FIG. 1, a portable infrared absorption methane detector, which includes a control circuit 1, a light source modulation circuit 2, a methane sensor 3, a signal conditioning circuit 4, an A/D conversion circuit 5 and a power supply Circuit 12, the control circuit 1 generates a modulation signal, and the light source modulation signal required by the methane sensor 3 is generated by the light source modulation circuit 2; the methane concentration acquisition signal output end of the methane sensor 3 and the acquisition signal input end of the signal conditioning circuit 4 Connect; the conditioning signal output end of the signal conditioning circuit 4 is connected with the analog signal input end of the A/D conversion circuit 5; the digital signal output end of the A/D conversion circuit 5 is connected with the digital signal input end of the control circuit; The power circuit 12 is used to provide working power to the detector.

Working principle: In this utility model, the timer inside the control module 1 and the light source modulation circuit 2 are used to jointly generate the modulation signal required by the methane sensor 3. The methane sensor 3 outputs two voltage signals, one corresponding to the methane concentration, and the other being Reference signal, the voltage signal is A/D sampled after signal conditioning, the A/D conversion circuit 5 converts the analog signal into a digital signal and sends it to the control module 1, and the control module 1 performs calculation and processing to obtain the detection result.

In this embodiment, a lithium battery circuit is used to supply power to the working components, and the lithium battery circuit is composed of a battery charging circuit and a voltage conversion circuit.

Embodiment 2. The difference between this embodiment and the portable infrared absorption methane detector described in Embodiment 1 is that it also includes a temperature/humidity measurement circuit 6, and the temperature/humidity of the temperature/humidity measurement circuit 6 is The measurement signal output terminal is connected with the temperature/humidity measurement signal input terminal of the control circuit 1 .

This embodiment can realize the detection of ambient temperature and humidity, and the temperature/humidity measurement circuit 6 is realized by using the SHT11 chip.

Embodiment 3. The difference between this embodiment and the portable infrared absorption methane detector described in Embodiment 1 or 2 is that it also includes a display circuit 9, the display signal input terminal of the display circuit 9 and the control circuit 1 display signal output connection.

Specific Embodiment 4. The difference between the specific embodiment and the portable infrared absorption methane detector described in the third specific embodiment is that the display circuit 9 is an LED display circuit.

In this embodiment, the LED display circuit is composed of 4 LED digital tubes, a display driver MC14499 and a current limiting resistor, and the control module 1 drives the light-emitting digital tubes to display the concentration of methane.

Embodiment 5. The difference between this embodiment and the portable infrared absorption methane detector described in Embodiment 1, 2 or 4 is that it also includes a button circuit 10, and the button signal output terminal of the button circuit 10 is connected to the The key signal input end of the control circuit 1 is connected.

Embodiment 6. The difference between this embodiment and the portable infrared absorption methane detector described in Embodiment 5 is that the key circuit 10 is a keyboard in the form of a 4×4 matrix.

Embodiment 7. The difference between this embodiment and the portable infrared absorption methane detector described in Embodiment 1, 2, 4 or 6 is that it also includes a sound and light alarm circuit 11, and the sound and light alarm circuit 11 The alarm signal input end of the control module 1 is connected with the alarm signal output end of the control module 1.

In this embodiment, if the detected methane concentration is higher than the set alarm value, the audible and visual alarm circuit 11 will issue an audible and visual alarm.

Embodiment 8. The difference between this embodiment and the portable infrared absorption methane detector described in Embodiment 7 is that it also includes a reset and watchdog circuit 7, and the reset of the reset and watchdog circuit 7 And the watchdog signal output end is connected with the reset signal input end of the control circuit 1.

The reset and watchdog circuit 7 in this embodiment is used to enable the control module to perform power-on reset and manual reset. The watchdog uses the X25045 chip, which can provide independent protection for the control module 1 .

Embodiment 9. The difference between this embodiment and the portable infrared absorption methane detector described in Embodiment 9 is that the control circuit 1 is realized by a single-chip microcomputer, and the single-chip microcomputer is a single-chip microcomputer whose model is AT89LV51.

Embodiment 10. The difference between this embodiment and the portable infrared absorption methane detector described in Embodiment 1, 2, 4, 6 or 8 is that the power circuit 12 is realized by a lithium battery.

In this embodiment, the single-chip microcomputer 1 is the core of the methane detector, and the AT89LV51 chip is selected to generate the light source modulation signal to complete functions such as data collection, processing, output, display and alarm; the output voltage of the light source modulation circuit 2 is the same frequency as the output modulation signal of the single-chip microcomputer , the output voltage is added to both ends of the light source; the methane sensor 3 is the key to accurately detect the concentration of methane gas, and the detector uses the IR32BC infrared absorption methane gas sensor; the signal conditioning circuit 4 amplifies and filters the analog signal, and then sends it to the analog signal. Digital conversion circuit for sampling; A/D conversion circuit 5 digitizes the amplified signal, using four-channel 12-bit A/D converter ADS784; temperature and humidity measurement 6 can measure ambient temperature and humidity, using SHT11 chip; The reset and watchdog circuit 7 enables the system to have power-on reset and manual reset. The watchdog selects the X25045 chip to provide independent protection for the single-chip system; the sound and light alarm circuit 8 provides sound and light alarm signals; the LED display circuit 9 consists of 4 Composed of LED digital tube, a display driver MC14499 and a current limiting resistor, the methane concentration and ambient temperature and humidity can be displayed in real time through the keyboard selection; key input 10 adopts a keypad in the form of a 4×4 matrix; the lithium battery circuit provides power for the system. The battery charging circuit and the voltage conversion circuit are composed of two parts.

Claims (10)

1. The portable infrared absorption methane detector is characterized in that it includes a control circuit (1), a light source modulation circuit (2), a methane sensor (3), a signal conditioning circuit (4), and an A/D conversion circuit (5) and a power supply circuit (12), the control circuit (1) generates a modulation signal, and the light source modulation signal required by the methane sensor (3) is generated by the light source modulation circuit (2); the methane concentration acquisition signal of the methane sensor (3) The output terminal is connected with the acquisition signal input terminal of the signal conditioning circuit (4); the conditioning signal output terminal of the signal conditioning circuit (4) is connected with the analog signal input terminal of the A/D conversion circuit (5); the A/D The digital signal output end of the conversion circuit (5) is connected with the digital signal input end of the control circuit; the power supply circuit (12) is used for providing working power to the detector. 2. The portable infrared absorption type methane detector according to claim 1 is characterized in that it also includes a temperature/humidity measurement circuit (6), and the temperature/humidity measurement signal output terminal of the temperature/humidity measurement circuit (6) It is connected with the temperature/humidity measurement signal input end of the control circuit (1). 3. according to claim 1 or 2 described portable infrared absorption type methane detectors, it is characterized in that it also comprises display circuit (9), the display signal input terminal of described display circuit (9) and control circuit (1) Shows signal output connections. 4. The portable infrared absorption methane detector according to claim 3, characterized in that the display circuit (9) is an LED display circuit. 5. The portable infrared absorption methane detector according to claim 1, 2 or 4, characterized in that it also includes a key circuit (10), the key signal output terminal of the key circuit (10) and the control circuit (1 ) is connected to the key signal input terminal. 6. The portable infrared absorption methane detector according to claim 5, characterized in that the button circuit (10) is a keyboard in the form of a 4×4 matrix. 7. according to the described portable infrared absorption methane detector of claim 1,2,4 or 6, it is characterized in that it also comprises acousto-optic alarm circuit (11), the alarm signal input of described acousto-optic alarm circuit (11) The terminal is connected with the alarm signal output terminal of the control module (1). 8. The portable infrared absorption methane detector according to claim 7, characterized in that it also includes a reset and watchdog circuit (7), and the reset and watchdog of the reset and watchdog circuit (7) The signal output end is connected with the reset signal input end of the control circuit (1). 9. The portable infrared absorption methane detector according to claim 1, 2, 4, 6 or 8, characterized in that the control circuit (1) is realized by a single-chip microcomputer, and the single-chip microcomputer is a single-chip microcomputer whose model is AT89LV51. 10. The portable infrared absorption methane detector according to claim 1, characterized in that the power supply circuit (12) is realized by a lithium battery.

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