Explosion-proof combustible gas detection device

Abstract

The utility model provides an explosion-proof combustible gas detection device. The explosion-proof combustible gas detection device comprises: an infrared absorption sensor configured to detect the concentration of combustible gas; the temperature detection module is configured to detect the temperature of the infrared absorption type sensor; the first input end of the comparison circuit is connected with the output end of the temperature detection module, the output end of the comparison circuit is connected to the control end of the multiplexer switch, the common end of the first switch of the multiplexer switch is connected with the first input end of the TEC module, and the common end of the second switch of the multiplexer switch is connected with the second input end of the TEC module. A first selection end of a first switch of the multiplexer switch is connected with a first power supply, and a second selection end of the first switch of the multiplexer switch is grounded. According to the invention, the detection precision of the combustible gas can be improved.

Description

Technical Field

[0001] This disclosure relates to the field of detection technology, and in particular to an explosion-proof combustible gas detection device. Background Technology

[0002] In industrial sites such as petrochemical plants, natural gas extraction facilities, and coal mines, a leak of flammable gases (such as methane, propane, and hydrogen) that reaches a certain concentration can potentially trigger an explosion upon contact with an ignition source. Flammable gas detection devices can monitor gas concentrations in real time. When the concentration reaches a certain percentage of the lower explosive limit, an alarm will sound, alerting personnel to take measures such as evacuating staff, shutting down equipment, and cutting off power, thereby effectively preventing explosions.

[0003] The most commonly used sensor in combustible gas detection devices is the infrared absorption sensor. It utilizes the absorption of infrared light of specific wavelengths by different gases, determining the concentration of combustible gas by emitting infrared light and detecting the degree of absorption. When the temperature exceeds the normal range, the absorption spectrum emitted by the infrared absorption sensor may drift, thus affecting the accuracy of gas detection. Utility Model Content

[0004] This disclosure provides an explosion-proof combustible gas detection device to improve the detection accuracy of combustible gases.

[0005] This disclosure provides an explosion-proof combustible gas detection device, comprising:

[0006] An infrared absorption sensor is configured to detect the concentration of combustible gas;

[0007] A temperature detection module is configured to detect the temperature of the infrared absorption sensor.

[0008] The comparison circuit has a first input terminal connected to the output terminal of the temperature detection module, a second input terminal connected to a first reference voltage, and a third input terminal connected to a second reference voltage. The first reference voltage is less than the second reference voltage. The output terminal of the comparison circuit is connected to the control terminal of a multiplexer switch.

[0009] The common terminal of the first switch of the multiplexer is connected to the first input terminal of the TEC module, the first selection terminal of the first switch of the multiplexer is connected to the first power supply, and the second selection terminal of the first switch of the multiplexer is grounded; the common terminal of the second switch of the multiplexer is connected to the second input terminal of the TEC module, the first selection terminal of the second switch of the multiplexer is grounded, and the second selection terminal of the second switch of the multiplexer is connected to the first power supply.

[0010] In one exemplary embodiment of this disclosure, the comparison circuit includes a first comparator and a second comparator. The non-inverting input of the first comparator is the second input of the comparison circuit, the inverting input of the first comparator is connected to the non-inverting input of the first comparator, the inverting input of the first comparator is the first input of the comparison circuit, and the inverting input of the second comparator is the third input of the comparison circuit.

[0011] The output of the first comparator is connected to the first input of the AND gate circuit via a NOT gate circuit, and the output of the second comparator is connected to the second input of the AND gate circuit. The output of the AND gate circuit is the output of the comparator circuit.

[0012] In one exemplary embodiment of this disclosure, a switching transistor Q2 is disposed between the first selection terminal of the first switch of the multiplexer and the first power supply, and a switching transistor Q3 is disposed between the second selection terminal of the second switch of the multiplexer and the first power supply.

[0013] The explosion-proof combustible gas detection device also includes an XOR gate circuit.

[0014] The first input terminal of the XOR gate circuit is connected to the output terminal of the second comparator, the second input terminal of the XOR gate circuit is connected to the output terminal of the first comparator, the output terminal of the XOR gate circuit is connected to the control terminal of the switching transistor Q2, the first terminal of the switching transistor Q2 is connected to the first power supply, and the second terminal of the switching transistor Q2 is connected to the first selection terminal of the first switch of the multiplexer.

[0015] The output terminal of the XOR gate circuit is connected to the control terminal of the switching transistor Q3. The first terminal of the switching transistor Q3 is connected to the first power supply, and the second terminal of the switching transistor Q3 is connected to the second selection terminal of the second switch of the multiplexer.

[0016] In one exemplary embodiment of this disclosure, the temperature detection module includes a resistor R1 and a thermistor RT.

[0017] The first end of the resistor R1 is connected to the first power supply, and the second end of the resistor R1 is grounded through the thermistor RT. The second end of the resistor R1 is the output end of the temperature detection module.

[0018] In one exemplary embodiment of this disclosure, the infrared absorption sensor includes a voltage regulator module and a laser diode.

[0019] The input terminal of the voltage regulator module is connected to the second power supply, the output terminal of the voltage regulator module is used to output the first power supply, the output terminal of the voltage regulator module is connected to the anode of the laser diode, and the cathode of the laser diode is grounded.

[0020] In one exemplary embodiment of this disclosure, the explosion-proof combustible gas detection device further includes a backup battery, a power management module, a switching transistor Q1, and a diode D1.

[0021] The positive terminal of the backup battery is connected to the power supply terminal of the power management module, the output terminal of the voltage regulator module is connected to the detection input terminal of the power management module, the drive output terminal of the power management module is connected to the control terminal of the switching transistor Q1, the first terminal of the switching transistor Q1 is connected to the positive terminal of the backup battery, and the second terminal of the switching transistor Q1 is connected to the first power supply.

[0022] The output terminal of the voltage regulator module is connected to the anode of diode D1, and the cathode of diode D1 is connected to the first power supply.

[0023] In one exemplary embodiment of this disclosure, the explosion-proof combustible gas detection device further includes a charging circuit.

[0024] The output of the voltage regulator module supplies power to the backup battery through the charging circuit.

[0025] The working principle and beneficial effects of the explosion-proof combustible gas detection device provided in this embodiment are as follows:

[0026] In this embodiment, the temperature detection module can detect the temperature of the infrared absorption sensor in real time. The comparison circuit compares the detected temperature with two different reference voltages (the first reference voltage is less than the second reference voltage) to determine the temperature state of the infrared absorption sensor. Based on the temperature state of the infrared absorption sensor, the TEC module is controlled to operate, and the temperature of the infrared absorption sensor is precisely controlled, avoiding problems such as sensor absorption spectrum drift caused by temperature changes. This improves the accuracy of combustible gas concentration detection and reduces false alarms and missed alarms, which is of great significance in scenarios with extremely high safety requirements such as explosion-proof environments. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a circuit diagram of an explosion-proof combustible gas detection device provided in an embodiment of this disclosure;

[0029] Figure 2 This is a circuit schematic diagram of the voltage regulator module provided in the embodiments of this disclosure;

[0030] Figure 3 This is a circuit schematic diagram of the power management module provided in an embodiment of this disclosure. Detailed Implementation

[0031] To enable those skilled in the art to better understand this solution, the technical solutions in the embodiments of this solution will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this solution, not all of them. Based on the embodiments of this solution, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this solution.

[0032] The term "comprising" and any other variations thereof in the specification, claims, and accompanying drawings of this invention mean "including but not limited to," and are intended to cover a non-exclusive inclusion, not limited to the examples listed herein. Furthermore, the terms "first" and "second," etc., are used to distinguish different objects, not to describe a specific order.

[0033] The implementation of this disclosure will be described in detail below with reference to the specific accompanying drawings:

[0034] Figure 1 A circuit diagram of an explosion-proof combustible gas detection device provided in an embodiment of this disclosure. (Refer to...) Figure 1 The explosion-proof combustible gas detection device includes:

[0035] An infrared absorption sensor is configured to detect the concentration of combustible gas;

[0036] The temperature detection module is configured to detect the temperature of the infrared absorption sensor.

[0037] The comparator circuit has its first input connected to the output of the temperature detection module, its second input connected to a first reference voltage, and its third input connected to a second reference voltage. The first reference voltage is less than the second reference voltage. The output of the comparator circuit is connected to the control terminal of a multiplexer switch.

[0038] The common terminal of the first switch of the multiplexer is connected to the first input terminal of the TEC module, the first selection terminal of the first switch of the multiplexer is connected to the first power supply, and the second selection terminal of the first switch of the multiplexer is grounded; the common terminal of the second switch of the multiplexer is connected to the second input terminal of the TEC module, the first selection terminal of the second switch of the multiplexer is grounded, and the second selection terminal of the second switch of the multiplexer is connected to the first power supply.

[0039] In this embodiment, the temperature detection module is used to detect the temperature of the infrared absorption sensor in real time. The comparison circuit compares the detected temperature with two different reference voltages (first reference voltage REF1 and second reference voltage REF2). When the output voltage of the temperature detection module is less than the first reference voltage REF1, it indicates that the temperature of the infrared absorption sensor is too low. When the output voltage of the temperature detection module is greater than the second reference voltage REF2, it indicates that the temperature of the infrared absorption sensor is too high.

[0040] The multiplexer U4 can specifically be a 74HC157, which contains four 2-to-1 selector switches. In this embodiment, the first and second switches of the multiplexer are used. By inputting a high-level control signal to the control terminal of the multiplexer U4, the common terminal of the first and second switches can be connected to the first selector terminal. Correspondingly, by inputting a low-level control signal to the control terminal of the multiplexer U4, the common terminal of the first and second switches can be connected to the second selector terminal.

[0041] The TEC module can use the TEC-127 semiconductor cooling chip, which has two pins, a positive pin and a negative pin. When current flows into the positive pin and out of the negative pin, the TEC-127 will generate a temperature difference between its two sides, thereby achieving the cooling function. Conversely, when the current direction changes, that is, when it flows into the negative pin and out of the positive pin, the TEC-127 will achieve the heating function.

[0042] When the temperature of the infrared absorption sensor is too high, the comparator circuit outputs a high-level signal to the control terminal of the multiplexer U4. The common terminal of the first and second switches is connected to the first selection terminal. The first input terminal of the TEC module is connected to the first power supply, and the second input terminal of the TEC module is grounded. The TEC module operates in cooling mode to cool the infrared absorption sensor. When the temperature of the infrared absorption sensor is too low, the comparator circuit outputs a low-level signal to the control terminal of the multiplexer U4. The common terminal of the first and second switches is connected to the second selection terminal. The second input terminal of the TEC module is connected to the first power supply, and the first input terminal of the TEC module is grounded. The TEC module operates in heating mode to heat the infrared absorption sensor.

[0043] As can be seen from the above, the temperature detection module in this embodiment can detect the temperature of the infrared absorption sensor in real time. The comparison circuit compares the detected temperature with two different reference voltages (the first reference voltage is less than the second reference voltage) to determine the temperature state of the infrared absorption sensor. Based on the temperature state of the infrared absorption sensor, the TEC module is controlled to operate, and the temperature of the infrared absorption sensor is precisely controlled, avoiding problems such as sensor absorption spectrum drift caused by temperature changes. This improves the accuracy of combustible gas concentration detection and reduces false alarms and missed alarms, which is of great significance in scenarios with extremely high safety requirements such as explosion protection.

[0044] Reference Figure 1 In one exemplary embodiment of this disclosure, the comparison circuit includes a first comparator and a second comparator. The non-inverting input of the first comparator is the second input of the comparison circuit, the inverting input of the first comparator is connected to the non-inverting input of the first comparator, the inverting input of the first comparator is the first input of the comparison circuit, and the inverting input of the second comparator is the third input of the comparison circuit.

[0045] The output of the first comparator is connected to the first input of the AND gate circuit through a NOT gate circuit, and the output of the second comparator is connected to the second input of the AND gate circuit. The output of the AND gate circuit is the output of the comparator circuit.

[0046] In this embodiment, the comparison circuit consists of a first comparator U3A and a second comparator U3B. When the temperature of the infrared absorption sensor is too high, the output voltage of the temperature detection module is greater than the second reference voltage REF2. The first comparator U3A outputs a low level, and the second comparator U3B outputs a high level. After the output of the first comparator U3A is inverted by the NOT gate U5A, the NOT gate U5A outputs a high level to the first input of the AND gate U8, and the second comparator U3B outputs a high level to the second input of the AND gate U8. The AND gate U8 outputs a high level to the control terminal of the multiplexer switch, controlling the TEC module to work in cooling mode.

[0047] When the temperature of the infrared absorption sensor is too low, the output voltage of the temperature detection module is less than the first reference voltage REF1. The first comparator U3A outputs a high level, and the second comparator U3B outputs a low level. After the output of the first comparator U3A is inverted by the NOT gate U5A, the NOT gate U5A outputs a low level to the first input of the AND gate U8. The second comparator U3B outputs a low level to the second input of the AND gate U8. The AND gate U8 outputs a low level to the control terminal of the multiplexer switch, controlling the TEC module to work in heating mode.

[0048] As can be seen from the above, the configuration of the first comparator U3A and the second comparator U3B in this embodiment can detect the temperature status of the infrared absorption sensor in real time, thereby providing a basis for the control of the TEC module.

[0049] Reference Figure 1 In one exemplary embodiment of this disclosure, a switching transistor Q2 is disposed between the first selection terminal of the first switch of the multiplexer and the first power supply, and a switching transistor Q3 is disposed between the second selection terminal of the second switch of the multiplexer and the first power supply.

[0050] Explosion-proof combustible gas detection devices also include XOR gate circuits.

[0051] The first input of the XOR gate is connected to the output of the second comparator, and the second input is connected to the output of the first comparator. The output of the XOR gate is connected to the control terminal of the switching transistor Q2. The first terminal of the switching transistor Q2 is connected to the first power supply, and the second terminal of the switching transistor Q2 is connected to the first selection terminal of the first switch of the multiplexer.

[0052] The output of the XOR gate is connected to the control terminal of the switch Q3. The first terminal of the switch Q3 is connected to the first power supply, and the second terminal of the switch Q3 is connected to the second selection terminal of the second switch of the multiplexer.

[0053] In this embodiment, when the temperature of the infrared absorption sensor is too high, the first comparator U3A outputs a low level to the first input terminal of the XOR gate circuit U10, the second comparator U3B outputs a high level to the second input terminal of the XOR gate circuit U10, the XOR gate circuit U10 outputs a high level signal to the control terminals of the switching transistors Q2 and Q3, the switching transistors Q2 and Q3 are turned on, the positive terminal of the TEC module is connected to the first power supply VCC, and the TEC module operates in cooling mode.

[0054] When the temperature of the infrared absorption sensor is too low, the first comparator U3A outputs a high level to the first input terminal of the XOR gate circuit U10, and the second comparator U3B outputs a low level to the second input terminal of the XOR gate circuit U10. The XOR gate circuit U10 outputs a high level signal to the control terminals of the switching transistors Q2 and Q3, and the switching transistors Q2 and Q3 are turned on. The negative terminal of the TEC module is connected to the first power supply VCC, and the TEC module operates in heating mode.

[0055] When the temperature of the infrared absorption sensor is within the normal temperature range, the output voltage of the temperature detection module is between the first reference voltage REF1 and the second reference voltage REF2. The first comparator U3A and the second comparator U3B both output low-level signals to the input of the XOR gate circuit U10. The XOR gate circuit U10 outputs low-level signals to the control terminals of the switching transistors Q2 and Q3. When the switching transistors Q2 and Q3 are turned off, the TEC module is powered off and stops working, which can save power consumption.

[0056] As can be seen from the above, the configuration of the XOR gate circuit U10, the switch Q2, and the switch Q3 in this embodiment can turn off the TEC module when the temperature of the infrared absorption sensor is within the normal temperature range, thereby reducing power consumption.

[0057] Reference Figure 1 In one exemplary embodiment of this disclosure, the temperature detection module includes a resistor R1 and a thermistor RT.

[0058] The first end of resistor R1 is connected to the first power supply, the second end of resistor R1 is grounded through the thermistor RT, and the second end of resistor R1 is the output terminal of the temperature detection module.

[0059] In this embodiment, resistor R1 and thermistor RT form a series voltage divider circuit. When the temperature of the infrared absorption sensor increases, the resistance of thermistor RT increases, and the output voltage of the temperature detection module increases. When the temperature of the infrared absorption sensor decreases, the resistance of thermistor RT decreases, and the output voltage of the temperature detection module decreases. Therefore, the temperature of the infrared absorption sensor can be obtained by detecting the output voltage of the temperature detection module.

[0060] As can be seen from the above, this embodiment uses resistor R1 and thermistor RT to realize the temperature detection of infrared absorption sensor, and the circuit structure is simple and easy to implement.

[0061] Reference Figure 2 In one exemplary embodiment of this disclosure, the infrared absorption sensor includes a voltage regulator module and a laser diode.

[0062] The input terminal of the voltage regulator module is connected to the second power supply, the output terminal of the voltage regulator module is used to output the first power supply, the output terminal of the voltage regulator module is connected to the anode of the laser diode, and the cathode of the laser diode is grounded.

[0063] In this embodiment, the second power supply is an external power supply. The voltage regulator module U1 specifically adopts LP3985. After being converted by the voltage regulator module U1, the external power supply provides a stable first power supply for the laser diode, which is beneficial for the laser diode to output infrared light with a stable wavelength.

[0064] Reference Figure 3In one exemplary embodiment of this disclosure, the explosion-proof combustible gas detection device further includes a backup battery, a power management module, a switching transistor Q1, and a diode D1.

[0065] The positive terminal of the backup battery is connected to the power supply terminal of the power management module, the output terminal of the voltage regulator module is connected to the detection input terminal of the power management module, the drive output terminal of the power management module is connected to the control terminal of the switching transistor Q1, the first terminal of the switching transistor Q1 is connected to the positive terminal of the backup battery, and the second terminal of the switching transistor Q1 is connected to the first power supply.

[0066] The output terminal of the voltage regulator module is connected to the anode of diode D1, and the cathode of diode D1 is connected to the first power supply.

[0067] In this embodiment, by setting up a backup battery and a power management module U2, when the external power supply is normal, the voltage VIN at the output of the voltage regulator module is greater than the voltage of the backup battery, the drive output of the power management module U2 is at a high level, the switching transistor Q1 is turned off, and the output of the voltage regulator module provides the first power supply VCC to the infrared absorption sensor through the diode D1; when the external power supply suddenly fails, the voltage VIN at the output of the voltage regulator module is less than the voltage of the backup battery, the drive output of the power management module U2 is at a low level, the drive switching transistor Q1 is turned on, and the backup battery provides the first power supply VCC to the infrared absorption sensor, thus avoiding the impact of sudden power failure on the normal operation of the infrared absorption sensor.

[0068] As can be seen from the above, the configuration of the backup battery and power management module U2 in this embodiment can ensure reliable power supply to the infrared absorption sensor and avoid missed detections caused by power outages.

[0069] Reference Figure 3 In one exemplary embodiment of this disclosure, an explosion-proof combustible gas detection device further includes a charging circuit.

[0070] The output of the voltage regulator module supplies power to the backup battery through a charging circuit.

[0071] In this embodiment, when the external power supply is normal, the output of the voltage regulator module charges the backup battery through the charging circuit, thereby ensuring that the backup battery has sufficient power.

[0072] The above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit it. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this disclosure.

Claims

1. An explosion-proof combustible gas detection device characterized by comprising: include: An infrared absorption sensor is configured to detect the concentration of combustible gas; A temperature detection module is configured to detect the temperature of the infrared absorption sensor. The comparison circuit has a first input terminal connected to the output terminal of the temperature detection module, a second input terminal connected to a first reference voltage, and a third input terminal connected to a second reference voltage. The first reference voltage is less than the second reference voltage. The output terminal of the comparison circuit is connected to the control terminal of a multiplexer switch. The common terminal of the first switch of the multiplexer is connected to the first input terminal of the TEC module, the first selection terminal of the first switch of the multiplexer is connected to the first power supply, and the second selection terminal of the first switch of the multiplexer is grounded; the common terminal of the second switch of the multiplexer is connected to the second input terminal of the TEC module, the first selection terminal of the second switch of the multiplexer is grounded, and the second selection terminal of the second switch of the multiplexer is connected to the first power supply.

2. The explosion-proof combustible gas detection device according to claim 1, wherein The comparison circuit includes a first comparator and a second comparator. The non-inverting input of the first comparator is the second input of the comparison circuit, and the inverting input of the first comparator is connected to its non-inverting input. The inverting input of the first comparator is the first input of the comparison circuit, and the inverting input of the second comparator is the third input of the comparison circuit. The output of the first comparator is connected to the first input of the AND gate circuit via a NOT gate circuit, and the output of the second comparator is connected to the second input of the AND gate circuit. The output of the AND gate circuit is the output of the comparator circuit.

3. The explosion-proof combustible gas detection device according to claim 2, wherein A switching transistor Q2 is provided between the first selection terminal of the first switch of the multiplexer and the first power supply, and a switching transistor Q3 is provided between the second selection terminal of the second switch of the multiplexer and the first power supply. The explosion-proof combustible gas detection device also includes an XOR gate circuit. The first input terminal of the XOR gate circuit is connected to the output terminal of the second comparator, the second input terminal of the XOR gate circuit is connected to the output terminal of the first comparator, the output terminal of the XOR gate circuit is connected to the control terminal of the switching transistor Q2, the first terminal of the switching transistor Q2 is connected to the first power supply, and the second terminal of the switching transistor Q2 is connected to the first selection terminal of the first switch of the multiplexer. The output terminal of the XOR gate circuit is connected to the control terminal of the switching transistor Q3. The first terminal of the switching transistor Q3 is connected to the first power supply, and the second terminal of the switching transistor Q3 is connected to the second selection terminal of the second switch of the multiplexer.

4. The explosion-proof combustible gas detection apparatus of claim 1, wherein The temperature detection module includes a resistor R1 and a thermistor RT. The first end of the resistor R1 is connected to the first power supply, and the second end of the resistor R1 is grounded through the thermistor RT. The second end of the resistor R1 is the output end of the temperature detection module.

5. The explosion-proof combustible gas detection apparatus of claim 1, wherein The infrared absorption sensor includes a voltage regulator module and a laser diode. The input end of the voltage stabilizing module is connected with the second power supply, the output end of the voltage stabilizing module is used for outputting the first power supply, the output end of the voltage stabilizing module is connected with the anode of the laser diode, and the cathode of the laser diode is grounded.

6. The explosion-proof combustible gas detection apparatus according to claim 5, wherein Further comprising a backup battery, a power management module, a switch tube Q1 and a diode D1, The positive pole of the backup battery is connected with the power supply end of the power management module, the output end of the voltage stabilizing module is connected with the detection input end of the power management module, the driving output end of the power management module is connected with the control end of the switch tube Q1, the first end of the switch tube Q1 is connected with the positive pole of the backup battery, and the second end of the switch tube Q1 is connected with the first power supply, The output end of the voltage stabilizing module is connected with the anode of the diode D1, and the cathode of the diode D1 is connected with the first power supply.

7. The explosion-proof combustible gas detection apparatus according to claim 6, wherein Further comprising a charging circuit, The output end of the voltage stabilizing module supplies power for the backup battery through the charging circuit.

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