Automatic calibration device for coal mine gas sensor and gas mixing method

Abstract

The invention relates to the technical field of coal mine gas sensor calibration, in particular to an automatic coal mine gas sensor calibration device and a gas mixing method.The automatic coal mine gas sensor calibration device comprises a zero gas assembly which comprises a zero gas cylinder and a zero gas pressure reducing valve connected with the zero gas cylinder; the standard gas assembly comprises a standard gas cylinder and a standard gas pressure reducing valve connected with the standard gas cylinder; the flow control assembly is connected with the zero gas pressure reducing valve and the standard gas pressure reducing valve so as to control the flow of the zero gas and the standard gas and enable the zero gas and the standard gas to be mixed according to a set proportion; the gas concentration sensor is connected with the flow control assembly so as to measure the actual gas concentration after the zero gas and the standard gas are mixed, and the actual gas concentration is fed back to the flow control assembly. Automatic gas mixing of zero gas and standard gas is achieved through the flow control assembly, gas concentration monitoring and feedback are conducted through the gas sensor, then gas with different specified concentrations needed by calibration is output, the number of sensors capable of being calibrated for single calibration operation underground is increased, and calibration compliance and accuracy are improved.

Description

Technical Field

[0001] The invention relates to the technical field of coal mine gas sensor calibration, and in particular to an automatic calibration device for a coal mine gas sensor and a gas mixing method. Background Art

[0002] At present, most coal mines use simple gas sensor calibrators for ventilation calibration. The main parts of the calibrator include: gas cylinders, pressure reducing valves and float flow meters. When using the calibrator for calibration, operators need to operate the remote control, pressure reducing valve, flow meter, timer, check the sensor, and observe the sensor value. The calibration process is complicated and the operation is cumbersome. The weight of the gas calibrator is generally more than 5kg, which is inconvenient to carry; the flow rate needs to be manually adjusted when using the calibrator, and the flow rate is difficult to control; the zero gas and standard gas of the calibrator need to be manually switched, and the pressure regulating valve needs to be frequently operated, resulting in serious gas waste. The overall intelligence and automation level of the calibrator is not high, which makes it impossible to quickly carry out the sensor calibration work, affecting the reliable operation of the sensor.

[0003] The calibration of underground sensors requires manual operation of pressure reducing valves, manual operation of flow meters, observation sensors, remote control sensors, operation timers, etc. The sensors need to be calibrated for zero point, calibration accuracy, and the alarm, power-off, and power-on functions of the sensors need to be tested during the calibration gas process (taking the methane sensor at the return air corner of the coal mining face as an example, the methane standard gas concentration is 2%, the alarm concentration is ≥1.0%, the power-off concentration is ≥1.5%, and the power-on concentration is <1.0%). A single person has to operate the sensor and control the gas calibrator, which is extremely cumbersome and the calibration efficiency is low. The standard gas concentration is fixed, and it is impossible to output gas of a specified concentration to test the sensor function at the corresponding concentration point. Only 2% concentration methane gas can be introduced at a small flow rate, hoping to complete the alarm, power-off, and power-on function tests during the process of the sensor value rising. However, on the one hand, it is not easy to accurately control the flow when manually adjusting the flow rate, and on the other hand, the sensor based on the existing laser detection principle responds very quickly, and the sensor value cannot effectively stay at the corresponding concentration.

[0004] Traditional gas calibration can only calibrate the zero point and the standard gas point concentration separately, and the accuracy of the two-point calibration is low. The actual concentration of the output standard gas cannot be effectively verified. The use of multi-point calibration can effectively improve the detection accuracy of the sensor and obtain the performance curve of the sensor itself.

[0005] According to the underground calibration process of coal mine sensors, the calibration flow rate of a single methane sensor is 200-300ml / min, and it generally takes 60s to pass zero gas and 300s to pass standard gas. The consumption of standard gas samples is much greater than that of zero gas samples, and zero gas samples cannot be consumed completely. Standard gas samples directly determine the number of sensors that can be calibrated in a single underground calibration operation. Increasing the volume of the standard gas cylinder will increase the difficulty of carrying, and there is also a problem of gas waste in the zero gas cylinder. Summary of the invention

[0006] The technical problem to be solved by the present invention is: in order to solve the technical problems in the prior art, the present invention provides a gas mixing method for an automatic calibration device for a coal mine gas sensor. The automatic calibration device can realize automatic mixing of zero gas and standard gas, and then output gases of different specified concentrations required for calibration, thereby reducing the difficulty of calibration operation, increasing the number of calibrable sensors in a single calibration operation underground, and improving the compliance and accuracy of calibration.

[0007] The technical solution adopted by the present invention to solve its technical problems is: an automatic calibration device for coal mine gas sensors, including a zero gas component, including a zero gas cylinder and a zero gas pressure reducing valve connected to the zero gas cylinder; a standard gas component, including a standard gas cylinder and a standard gas pressure reducing valve connected to the standard gas cylinder; a flow control component, connected to the zero gas pressure reducing valve and the standard gas pressure reducing valve, to control the flow of zero gas and standard gas, and to mix the zero gas and standard gas according to a set ratio; a gas concentration sensor, connected to the flow control component, to measure the actual gas concentration after the zero gas and standard gas are mixed, and feed back to the flow control component.

[0008] The automatic calibration device for coal mine gas sensors of the present invention realizes automatic mixing of zero gas and standard gas through a flow control component, monitors and feedbacks gas concentration through a gas sensor, and then outputs gases of different specified concentrations required for calibration, thereby increasing the number of sensors that can be calibrated in a single calibration operation underground, and improving the compliance and accuracy of calibration. The traditional gas cylinder calibration method can only realize two-point calibration of zero concentration and standard gas concentration, and the calibration points are limited. The output signal of the probe and the gas concentration are generally nonlinear. The two-point calibration will cause local distortion of the detection value in the intermediate concentration section between zero gas and standard gas. The present solution can realize multi-point calibration with full coverage at multiple points, and the calibration accuracy is higher.

[0009] Further, the flow control assembly includes a zero gas electromagnetic proportional valve, a standard gas electromagnetic proportional valve, a zero gas flow sensor and a standard gas flow sensor, one end of the zero gas electromagnetic proportional valve is connected to the zero gas pressure reducing valve, and the other end is connected to the zero gas flow sensor, and the zero gas flow sensor is connected to the gas concentration sensor;

[0010] One end of the standard gas electromagnetic proportional valve is connected to the standard gas pressure reducing valve, and the other end is connected to the standard gas flow sensor, and the standard gas flow sensor is connected to the gas concentration sensor.

[0011] Furthermore, the flow control component includes a zero gas solenoid switch valve, a standard gas solenoid switch valve, a total solenoid proportional valve and a total flow sensor, one end of the zero gas solenoid switch valve is connected to the zero gas pressure reducing valve, and the other end is connected to the total solenoid proportional valve, one end of the standard gas solenoid switch valve is connected to the standard gas pressure reducing valve, and the other end is connected to the total solenoid proportional valve, the total solenoid proportional valve is connected to the total flow sensor, and the total flow sensor is connected to the gas concentration sensor.

[0012] Furthermore, a one-way valve is provided between the zero gas component and the gas concentration sensor, and between the standard gas component and the gas concentration sensor to prevent the gas from flowing back to the zero gas component or the standard gas component.

[0013] Furthermore, a filter is provided between the zero gas component or the standard gas component and the gas concentration sensor to remove impurities and moisture in the pipeline.

[0014] Furthermore, it also includes a control device, which is electrically connected to the gas concentration sensor and the flow control component to receive signals transmitted by the gas concentration sensor and the flow control component, and complete linear adjustment of the calibrated sensor according to the ventilation flow, gas concentration and ventilation duration.

[0015] A gas mixing method for an automatic calibration device for a coal mine gas sensor, based on the automatic calibration device for a coal mine gas sensor, comprises the following steps:

[0016] S1, the zero gas cylinder supplies zero gas to the zero gas pressure reducing valve, and the zero gas pressure reducing valve outputs zero gas at a constant pressure, and at the same time, the standard gas cylinder supplies standard gas to the standard gas pressure reducing valve, and the standard gas pressure reducing valve outputs standard gas at a constant pressure;

[0017] S2, the flow sensor monitors the flow rate output by the zero-gas electromagnetic proportional valve, and feeds back the signal to the control device, and the control device controls the flow rate output by the zero-gas electromagnetic proportional valve;

[0018] S3, the flow sensor monitors the flow rate output by the standard gas electromagnetic proportional valve, and feeds back the signal to the control device, and the control device controls the flow rate output by the standard gas electromagnetic proportional valve;

[0019] S4. The gas concentration sensor monitors the concentration of zero gas and standard gas output by the zero gas electromagnetic proportional valve and the standard gas electromagnetic proportional valve, and transmits the signal to the control device, and the control device completes the linear adjustment of the calibrated sensor according to the ventilation flow, gas concentration and ventilation duration.

[0020] Furthermore, in step S2, the zero air flow sensor adopts a thermal mass flow sensor, which outputs a 0-5VDC signal through a built-in temperature and pressure compensation module to achieve accurate measurement and digital feedback of the mass flow rate; the zero air flow sensor is calibrated through a float flowmeter to achieve accurate measurement of the volume flow rate; the flow sensor feeds back the flow measurement data to the control device, and the control device adjusts the PWM pulse of the zero air solenoid proportional valve according to the PID control algorithm, thereby achieving automatic control of the flow rate.

[0021] A gas mixing method for an automatic calibration device for a coal mine gas sensor, based on the above-mentioned automatic calibration device for a coal mine gas sensor, comprises the following steps: comprising the following steps: S1, the zero gas cylinder supplies zero gas to the zero gas pressure reducing valve, and the zero gas pressure reducing valve outputs zero gas of constant pressure, and at the same time the standard gas cylinder supplies standard gas to the standard gas pressure reducing valve, and the standard gas pressure reducing valve outputs standard gas of constant pressure; S2, the zero gas electromagnetic switch valve outputs zero gas of a fixed flow rate, and the standard gas electromagnetic switch valve outputs standard gas of a fixed flow rate; S3, the total flow sensor monitors the flow rate output by the total electromagnetic proportional valve, and feeds back the signal to the control device, and the control device controls the flow rate output by the total electromagnetic proportional valve to achieve stable output control of the flow rate; S4, the gas concentration sensor monitors the concentration of zero gas and standard gas output by the total electromagnetic proportional valve, and transmits the signal to the control device, and the control device completes the linear adjustment of the calibrated sensor according to the ventilation flow rate, gas concentration and ventilation duration.

[0022] Furthermore, in step S2, pulse width modulation is used to control the zero gas electromagnetic switch valve and the standard gas electromagnetic switch valve. When the frequency is constant, the duty cycle of the drive voltage PWM control signal is changed to realize the flow ratio function of the switch electromagnetic valve.

[0023] The beneficial effects of the present invention are:

[0024] 1. Automatic mixing of zero gas and standard gas is achieved through flow control components, and gas concentration is monitored and fed back through gas sensors, thereby outputting gases of different specified concentrations required for calibration, increasing the number of sensors that can be calibrated in a single downhole calibration operation, and improving the compliance and accuracy of calibration. The traditional gas cylinder calibration method can only achieve two-point calibration of zero concentration and standard gas concentration. The calibration points are limited, and the output signal of the probe and the gas concentration are generally nonlinear. The two-point calibration will cause local distortion of the detection value in the concentration section between zero gas and standard gas. This solution can achieve multi-point, full-coverage multi-point calibration, with higher calibration accuracy.

[0025] 2. Accurate output of zero gas and standard gas is achieved through zero gas flow controller, standard gas flow controller, zero gas solenoid proportional valve and standard gas solenoid proportional valve. Gas concentration is monitored through gas concentration sensor. Dual-channel flow control unit is used to achieve automatic setting and self-check of gas concentration of two gas channels, thereby improving the accuracy of calibration.

[0026] 3. Through the zero gas solenoid switch valve, the standard gas solenoid switch valve and the total solenoid proportional valve, a dual-channel flow switch unit and a single-channel flow control unit are realized. While achieving gas mixing and output, two low-cost solenoid switch valves are used to replace a set of high-cost solenoid proportional valves and flow controllers, which greatly reduces the cost and the difficulty of industrialization.

[0027] 4. Based on the automatic flow control output, the steps of personnel operating the gas circuit are omitted. Through the data exchange with the sensor, the control and calibration operation of the sensor is realized, which greatly reduces the difficulty of calibration and improves the efficiency of calibration. The gas mixing scheme can output the gas of the specified concentration as needed to ensure the smooth progress of the sensor function test, which significantly improves the quality and success rate of downhole calibration;

[0028] 5. Based on the gas mixing solution of this application, the number of calibrable sensors of the calibration device can be greatly increased on the basis of the same pressure and volume gas cylinders, thereby reducing gas waste and the workload of gas cylinder maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0030] Figure 1 It is a schematic diagram of the overall structure of the automatic calibration device for coal mine gas sensors in Example 1 of the present invention.

[0031] Figure 2 It is a schematic diagram showing the relationship between the output flow rate and the driving current of the electromagnetic proportional valve in the present invention.

[0032] Figure 3 It is a schematic diagram of the overall structure of the automatic calibration device for coal mine gas sensors in Example 2 of the present invention.

[0033] In the figure: 1. Zero gas cylinder; 11. Zero gas pressure reducing valve; 2. Standard gas cylinder; 21. Standard gas pressure reducing valve; 3. Flow control component; 31. Zero gas solenoid proportional valve; 32. Standard gas solenoid proportional valve; 33. Zero gas flow sensor; 34. Standard gas flow sensor; 35. Zero gas solenoid switch valve; 36. Standard gas solenoid switch valve; 37. Total solenoid proportional valve; 38. Total flow sensor; 4. Gas concentration sensor; 5. Check valve; 6. Filter; 7. Control device. DETAILED DESCRIPTION

[0034] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0035] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more. In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a connection between the two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] The invention discloses an automatic calibration device for a coal mine gas sensor and a gas mixing method.

[0037] Reference Figure 1, a coal mine gas sensor automatic calibration device, including a zero gas component, a standard gas component, a flow control component 3, a gas concentration sensor 4 and a control device 7, the zero gas component includes a zero gas cylinder 1 and a zero gas pressure reducing valve 11 connected to the zero gas cylinder 1, the standard gas component includes a standard gas cylinder 2 and a standard gas pressure reducing valve 21 connected to the standard gas cylinder 2, the flow control component 3 is connected to the zero gas pressure reducing valve 11 and the standard gas pressure reducing valve 21 to control the flow of zero gas and standard gas, and make the zero gas and standard gas mix according to the set ratio. The gas concentration sensor 4 is connected to the flow control component 3 to measure the actual gas concentration after the zero gas and the standard gas are mixed, and feedback is given to the flow control component 3. The control device 7 is electrically connected to the gas concentration sensor 4 and the flow control component 3 to receive the signals transmitted by the gas concentration sensor 4 and the flow control component 3, and completes the linear adjustment of the calibrated sensor according to the ventilation flow, gas concentration and ventilation duration. By mixing the zero gas and the standard gas through the flow control component 3, any concentration of gas can be output between the zero point and the standard gas point, which increases the calibration points and improves the calibration accuracy. At the same time, the built-in high-precision gas sensor can be used as a calibration reference to ensure the calibration accuracy of the calibrated sensor. At the same time, the automatic calibration method is adopted, and the operator does not need to operate the remote control and timer, nor does it need to manually operate the flow meter and pressure reducing valve, which greatly improves the calibration efficiency, reduces the difficulty of calibration, and reduces the possibility of non-compliant calibration operations.

[0038] A one-way valve 5 is provided between the zero gas component and the gas concentration sensor 4, and between the standard gas component and the gas concentration sensor 4 to prevent the gas from flowing back to the zero gas component or the standard gas component. A filter 6 is provided between the zero gas component or the standard gas component and the gas concentration sensor 4 to remove impurities and moisture in the pipeline, ensure the pipeline is unobstructed, and protect the equipment from working stably and reliably for a long time.

[0039] In this application, the zero gas cylinder 1 is filled with the gas required for zero point adjustment of the calibrated sensor, usually air or nitrogen. The standard gas cylinder 2 is filled with the gas required for linear adjustment of the calibrated sensor, and the gas is determined by the type of the calibrated sensor. For example, when calibrating a methane sensor, the standard gas is usually 2% methane.

[0040] This application adopts an automatic calibration method, and the number of calibrations is greatly increased compared to traditional non-automatic calibration devices. Taking the calibration of methane sensors as an example, according to the underground calibration process of coal mine sensors, the calibration flow rate of a single methane sensor is 200 to 300 ml / min, and generally requires 60 seconds of zero gas and 300 seconds of standard gas. The consumption of standard gas samples is much greater than that of zero gas samples, and zero gas samples cannot be consumed. The standard gas samples directly determine the number of sensors that can be calibrated in a single underground calibration operation. In this solution, the standard gas cylinder 2 can be filled with a higher concentration of calibration gas, and then diluted with zero gas. The gas is mixed in real time through automatic calibration to output a standard gas of a specified concentration, thereby maximizing the use of standard gas and zero gas, greatly increasing the number of sensors that can be calibrated in a single underground calibration operation.

[0041] The comparison of methane sensor calibration quantity data is as follows:

[0042] No automatic calibration device is used: a traditional calibration device with a gas cylinder and a float flowmeter is used. The calibration gas cylinder 2 is filled with 2% methane, and the calibration gas cylinder 2 outputs 2% methane. The gas cylinder with a specification of 0.25L and 5MPa is deflated at a pressure of 0.15MPa and a working condition of 200ml / min, and the deflation end pressure is 0.15MPa. When calibrating a single methane sensor, zero gas is required for 1 minute, and 2% concentration calibration gas is required for 5 minutes.

[0043] The number of methane sensors that can be calibrated with zero gas is: (0.25L×(5-0.15)MPa) / (0.2L / min×1min×0.15MPa)=40.4 sets;

[0044] The number of methane sensors that can be calibrated with standard gas is: (0.25L×(5-0.15)MPa) / (0.2L / min×5min×0.15MPa)=8.1 sets;

[0045] That is, the number of sensors that can be calibrated by the traditional calibration device is about 8.

[0046] Use automatic calibration device: use real-time gas mixing to output calibration gas. The calibration gas cylinder is set to 3.33% methane, and the calibration device outputs 2% methane. The gas cylinder with specifications of 0.25L and 10MPa is deflated at 0.15MPa pressure and 200ml / min, and the deflation end pressure is 0.15MPa. When calibrating a single methane sensor, zero gas is required for 1 minute, and 2% concentration calibration gas is required for 5 minutes. Dilute the zero gas and 3.33% concentration calibration gas in a ratio of 2:3, transmit zero gas for 2 minutes, and output calibration gas for 3 minutes.

[0047] The number of methane sensors that can be calibrated with zero gas is: (0.25L×(5-0.15)MPa) / (0.2L / min×3min×0.15MPa)=13.8 sets;

[0048] The number of methane sensors that can be calibrated with standard gas is: (0.25L×(5-0.15)MPa) / (0.2L / min×3min×0.15MPa)=13.8 sets;

[0049] That is, the number of sensors that can be calibrated by the automatic calibration device is about 13, which is 62.5% higher than that of traditional calibration devices.

[0050] Embodiment 1:

[0051] Reference Figure 1 The flow control component 3 includes a zero gas electromagnetic proportional valve 31, a standard gas electromagnetic proportional valve 32, a zero gas flow sensor 33 and a standard gas flow sensor 34. One end of the zero gas electromagnetic proportional valve 31 is connected to the zero gas pressure reducing valve 11, and the other end is connected to the zero gas flow sensor 33. The zero gas flow sensor 33 is connected to the gas concentration sensor 4. One end of the standard gas electromagnetic proportional valve 32 is connected to the standard gas pressure reducing valve 21, and the other end is connected to the standard gas flow sensor 34. The standard gas flow sensor 34 is connected to the gas concentration sensor 4. The zero gas and standard gas are accurately output by the zero gas flow controller, the standard gas flow controller, the zero gas electromagnetic proportional valve 31 and the standard gas electromagnetic proportional valve 32, and the gas concentration is monitored by the gas concentration sensor 4. A dual-path flow control unit is used to realize the automatic setting and self-check of the gas concentration of the two gas paths, thereby improving the accuracy of calibration.

[0052] Specifically, the zero gas pressure reducing valve 11 and the standard gas pressure reducing valve 21 can both be constant pressure reducing valves to ensure that the outlet pressure of the zero gas cylinder 1 and the standard gas cylinder 2 is constant, and the outlet pressure will not be affected by the reduction of the cylinder pressure. After the cylinder pressure is reduced to the outlet pressure, the deflation stops. In this embodiment, the outlet pressure is set to 0.15MPa.

[0053] Use electromagnetic proportional valve as flow proportion control unit, refer to Figure 2 , when the pressure difference between the inlet and outlet of the electromagnetic proportional valve is constant, the driving current is proportional to the output flow. The electromagnetic proportional valve is driven by a PWM pulse signal. By controlling the duty cycle of the PWM pulse, the average driving current of the proportional valve port can be controlled, thereby achieving the purpose of controlling the flow. Preferably, the electromagnetic proportional valve can adopt the VSO series of Parker of the United States to achieve extremely low power consumption and ultra-small size.

[0054] A flow sensor is used as a flow detection unit. In this embodiment, the flow sensor can be a thermal mass flow sensor with a built-in temperature and pressure compensation module, which outputs a 0-5VDC signal to achieve accurate measurement and digital feedback of mass flow. Before use, the flow sensor can be calibrated by a float flowmeter to achieve accurate measurement of volume flow. During operation, the flow sensor feeds back the flow measurement data to the control device 7, and the control device 7 adjusts the PWM pulse of the solenoid valve according to the PID control algorithm to achieve automatic control of the flow. In this embodiment, the control device 7 can be a single-chip microcomputer.

[0055] The gas concentration sensor 4 serves as a gas concentration detection unit. The measurement accuracy and stability of the gas concentration sensor 4 are much higher than those of the calibrated sensor. An air inlet for calibration can be reserved on the sensor so that it can be calibrated regularly with standard gas. The gas concentration sensor 4 is used to measure the actual gas concentration after the zero gas and the standard gas are mixed, and the concentration measurement data is fed back to the control device 7. The control device 7 completes the linear adjustment of the calibrated sensor according to the ventilation flow, gas concentration, ventilation duration and other data. In addition, during the setting stage, the control device 7 can successively open the solenoid valves of the zero gas and the standard gas separately, and use the gas concentration sensor 4 to complete the detection of the concentration of the two gas paths, so as to achieve the purpose of automatic setting and self-checking of the gas concentration of the two gas paths.

[0056] In this embodiment, two one-way valves 5 are preferably provided, one is arranged between the zero gas electromagnetic proportional valve 31 and the zero gas flow sensor 33, and the other is arranged between the standard gas electromagnetic proportional valve 32 and the standard gas flow sensor 34. In this embodiment, two filters 6 are preferably provided, one is arranged between the zero gas pressure reducing valve 11 and the zero gas electromagnetic proportional valve 31, and the other is arranged between the standard gas pressure reducing valve 21 and the standard gas electromagnetic proportional valve 32.

[0057] A gas mixing method for an automatic calibration device for a coal mine gas sensor, based on the automatic calibration device for a coal mine gas sensor, comprises the following steps:

[0058] S1, zero gas cylinder 1 supplies zero gas to zero gas pressure reducing valve 11, zero gas pressure reducing valve 11 outputs zero gas of constant pressure, meanwhile standard gas cylinder 2 supplies standard gas to standard gas pressure reducing valve 21, standard gas pressure reducing valve 21 outputs standard gas of constant pressure. At this time, control device 7 opens zero gas electromagnetic proportional valve 31 and standard gas electromagnetic proportional valve 32 separately in sequence, and uses gas concentration sensor 4 to complete the detection of concentration of zero gas and standard gas in two gas paths, so as to realize automatic setting and self-check of gas concentration of two gas paths.

[0059] S2. Then, the zero gas flow sensor 33 monitors the flow output by the zero gas electromagnetic proportional valve 31 and feeds back the signal to the control device 7. The control device 7 controls the flow output by the zero gas electromagnetic proportional valve 31.

[0060] S3, the standard gas flow sensor 34 monitors the flow output by the standard gas electromagnetic proportional valve 32, and feeds back the signal to the control device 7, and the control device 7 controls the flow output by the standard gas electromagnetic proportional valve 32.

[0061] S4, the gas concentration sensor 4 monitors the concentration of the zero gas and the standard gas output by the zero gas electromagnetic proportional valve 31 and the standard gas electromagnetic proportional valve 32, and transmits the signal to the control device 7, and the control device 7 completes the linear adjustment of the calibrated sensor according to the ventilation flow, gas concentration and ventilation duration.

[0062] Embodiment 2:

[0063] Reference Figure 3 , which is different from Example 1, is that the flow control component 3 includes a zero gas electromagnetic switch valve 35, a standard gas electromagnetic switch valve 36, a total electromagnetic proportional valve 37 and a total flow sensor 38, one end of the zero gas electromagnetic switch valve 35 is connected to the zero gas pressure reducing valve 11, and the other end is connected to the total electromagnetic proportional valve 37, one end of the standard gas electromagnetic switch valve 36 is connected to the standard gas pressure reducing valve 21, and the other end is connected to the total electromagnetic proportional valve 37, the total electromagnetic proportional valve 37 is connected to the total flow sensor 38, and the total flow sensor 38 is connected to the gas concentration sensor 4. The zero gas electromagnetic switch valve 35, the standard gas electromagnetic switch valve 36 and the total electromagnetic proportional valve 37 realize a dual-channel flow switch unit and a single-channel flow control unit, while realizing gas mixing and output, using two low-cost electromagnetic switch valves to replace a set of high-cost electromagnetic proportional valves and flow controllers, which greatly reduces the cost and reduces the difficulty of industrialization.

[0064] In this embodiment, two one-way valves 5 are preferably provided, one is arranged between the zero gas electromagnetic switch valve 35 and the main electromagnetic proportional valve 37, and the other is arranged between the standard gas electromagnetic switch valve 36 and the main electromagnetic proportional valve 37. In this embodiment, two filters 6 are preferably provided, one is arranged between the zero gas pressure reducing valve 11 and the zero gas electromagnetic switch valve 35, and the other is arranged between the standard gas pressure reducing valve 21 and the electromagnetic switch valve.

[0065] A gas mixing method for an automatic calibration device for a coal mine gas sensor, based on the automatic calibration device for a coal mine gas sensor, comprises the following steps:

[0066] S1, the zero gas cylinder 1 supplies zero gas to the zero gas pressure reducing valve 11, and the zero gas pressure reducing valve 11 outputs zero gas of constant pressure, and the standard gas cylinder 2 supplies standard gas to the standard gas pressure reducing valve 21, and the standard gas pressure reducing valve 21 outputs standard gas of constant pressure. At this time, the control device 7 opens the zero gas electromagnetic switch valve 35 and the standard gas electromagnetic switch valve 36 in sequence, and uses the gas concentration sensor 4 to complete the detection of the concentration of the two gas paths of zero gas and standard gas, and realizes the automatic setting and self-check of the gas concentration of the two gas paths.

[0067] S2, the zero gas electromagnetic switch valve 35 outputs a fixed flow of zero gas, and the standard gas electromagnetic switch valve 36 outputs a fixed flow of standard gas. The zero gas electromagnetic switch valve 35 and the standard gas electromagnetic switch valve 36 are controlled by pulse width modulation. When the frequency is constant, the duty cycle of the driving voltage PWM control signal is changed to realize the flow ratio function of the switch solenoid valve.

[0068] S3, the total flow sensor 38 monitors the flow output by the total electromagnetic proportional valve 37, and feeds back the signal to the control device 7, and the control device 7 controls the flow output by the total electromagnetic proportional valve 37 to achieve stable output control of the flow.

[0069] S4, the gas concentration sensor 4 monitors the concentration of the zero gas and the standard gas output by the total electromagnetic proportional valve 37, and transmits the signal to the control device 7. The control device 7 adjusts the driving voltage duty cycle of the two-way switch electromagnetic valves in real time according to the deviation between the current concentration and the target concentration, and the control device 7 completes the linear adjustment of the calibrated sensor according to the ventilation flow, gas concentration and ventilation duration.

[0070] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. An automatic calibration device for coal mine gas sensors, characterized in that: include A zero gas assembly, comprising a zero gas cylinder (1) and a zero gas pressure reducing valve (11) connected to the zero gas cylinder (1); A calibration gas assembly, comprising a calibration gas cylinder (2) and a calibration gas pressure reducing valve (21) connected to the calibration gas cylinder (2); A flow control component (3) is connected to the zero gas pressure reducing valve (11) and the standard gas pressure reducing valve (21) to control the flow of the zero gas and the standard gas and to mix the zero gas and the standard gas according to a set ratio; The gas concentration sensor (4) is connected to the flow control component (3) to measure the actual gas concentration after the zero gas and the standard gas are mixed, and feeds back to the flow control component (3).

2. The automatic calibration device for coal mine gas sensors according to claim 1 is characterized in that: The invention also comprises a control device (7), wherein the control device (7) is electrically connected to the gas concentration sensor (4) and the flow control component (3) so as to receive signals transmitted by the gas concentration sensor (4) and the flow control component (3) and complete linear adjustment of the calibrated sensor according to the ventilation flow, gas concentration and ventilation duration.

3. The automatic calibration device for coal mine gas sensors according to claim 2 is characterized in that: The flow control component (3) comprises a zero gas electromagnetic proportional valve (31), a standard gas electromagnetic proportional valve (32), a zero gas flow sensor (33) and a standard gas flow sensor (34); one end of the zero gas electromagnetic proportional valve (31) is connected to the zero gas pressure reducing valve (11), and the other end is connected to the zero gas flow sensor (33); the zero gas flow sensor (33) is connected to the gas concentration sensor (4); One end of the standard gas electromagnetic proportional valve (32) is connected to the standard gas pressure reducing valve (21), and the other end is connected to the standard gas flow sensor (34), and the standard gas flow sensor (34) is connected to the gas concentration sensor (4).

4. The automatic calibration device for coal mine gas sensors according to claim 2 is characterized in that: The flow control component (3) comprises a zero gas electromagnetic switch valve (35), a standard gas electromagnetic switch valve (36), a total electromagnetic proportional valve (37) and a total flow sensor (38); one end of the zero gas electromagnetic switch valve (35) is connected to the zero gas pressure reducing valve (11), and the other end is connected to the total electromagnetic proportional valve (37); one end of the standard gas electromagnetic switch valve (36) is connected to the standard gas pressure reducing valve (21), and the other end is connected to the total electromagnetic proportional valve (37); the total electromagnetic proportional valve (37) is connected to the total flow sensor (38), and the total flow sensor (38) is connected to the gas concentration sensor (4).

5. The automatic calibration device for coal mine gas sensors according to claim 1, characterized in that: A filter (6) is provided between the zero gas component or the standard gas component and the gas concentration sensor (4) to remove impurities and moisture in the pipeline.

6. The automatic calibration device for coal mine gas sensors according to claim 1, characterized in that: A one-way valve (5) is provided between the zero gas component and the gas concentration sensor (4), and between the standard gas component and the gas concentration sensor (4) to prevent the gas from flowing back to the zero gas component or the standard gas component.

7. A gas mixing method for an automatic calibration device for a coal mine gas sensor, based on the automatic calibration device for a coal mine gas sensor according to claim 3, characterized in that: The steps include: S1, the zero gas cylinder (1) supplies zero gas to the zero gas pressure reducing valve (11), and the zero gas pressure reducing valve (11) outputs zero gas at a constant pressure, and at the same time, the standard gas cylinder (2) supplies standard gas to the standard gas pressure reducing valve (21), and the standard gas pressure reducing valve (21) outputs standard gas at a constant pressure; S2, the zero gas flow sensor (33) monitors the flow rate output by the zero gas electromagnetic proportional valve (31), and feeds back the signal to the control device (7), and the control device (7) controls the flow rate output by the zero gas electromagnetic proportional valve (31); S3, the standard gas flow sensor (34) monitors the flow rate output by the standard gas electromagnetic proportional valve (32), and feeds back the signal to the control device (7), and the control device (7) controls the flow rate output by the standard gas electromagnetic proportional valve (32); S4, the gas concentration sensor (4) monitors the concentrations of the zero gas and the standard gas output by the zero gas electromagnetic proportional valve (31) and the standard gas electromagnetic proportional valve (32), and transmits the signal to the control device (7), and the control device (7) completes the linear adjustment of the calibrated sensor according to the ventilation flow, gas concentration and ventilation duration.

8. The gas mixing method of the automatic calibration device for coal mine gas sensors according to claim 7, characterized in that: In step S2, the zero gas flow sensor (33) adopts a thermal mass flow sensor, which outputs a 0-5VDC signal through a built-in temperature and pressure compensation module to achieve accurate measurement and digital feedback of the mass flow; The zero air flow sensor (33) is calibrated by a float flowmeter, thereby realizing accurate measurement of the volume flow rate; the flow sensor feeds back the flow measurement data to the control device (7), and the control device (7) adjusts the PWM pulse of the zero air electromagnetic proportional valve (31) according to the PID control algorithm, thereby realizing automatic control of the flow rate.

9. A gas mixing method for an automatic calibration device for a coal mine gas sensor, based on the automatic calibration device for a coal mine gas sensor according to claim 4, characterized in that: The method comprises the following steps: S1, the zero gas cylinder (1) supplies zero gas to the zero gas pressure reducing valve (11), and the zero gas pressure reducing valve (11) outputs zero gas at a constant pressure, and at the same time, the standard gas cylinder (2) supplies standard gas to the standard gas pressure reducing valve (21), and the standard gas pressure reducing valve (21) outputs standard gas at a constant pressure; S2, the zero gas electromagnetic switch valve (35) outputs a fixed flow of zero gas, and the standard gas electromagnetic switch valve (36) outputs a fixed flow of standard gas; S3, the total flow sensor (38) monitors the flow output by the total electromagnetic proportional valve (37), and feeds back the signal to the control device (7), and the control device (7) controls the flow output by the total electromagnetic proportional valve (37) to achieve stable output control of the flow; S4, the gas concentration sensor (4) monitors the concentration of the zero gas and the standard gas output by the main electromagnetic proportional valve (37), and transmits the signal to the control device (7), and the control device (7) completes the linear adjustment of the calibrated sensor according to the ventilation flow, gas concentration and ventilation duration.

10. The gas mixing method of the automatic calibration device for coal mine gas sensors according to claim 9, characterized in that: In step S2, pulse width modulation is used to control the zero gas electromagnetic switch valve (35) and the standard gas electromagnetic switch valve (36). When the frequency is constant, the duty cycle of the drive voltage PWM control signal is changed to realize the flow ratio function of the switch electromagnetic valve.

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