Pipeline hydrogen leakage on-line monitoring device

Abstract

The pipeline hydrogen leakage online monitoring device comprises a shell, a temperature monitoring module, a laser light source, a laser receiving unit, a standby monitoring module, a hydrogen monitoring module, a reflecting lens and a power module, and the temperature monitoring module, the standby monitoring module and the hydrogen monitoring module are all arranged on the first side wall of the shell; the laser light source is arranged on the second side wall of the shell, the first side wall of the shell is adjacent to the second side wall of the shell, a plurality of air inlets are formed in the third side wall of the shell, the third side wall of the shell is opposite to the second side wall of the shell, the laser receiving unit is arranged on the bottom face wall of the shell, and the reflecting lens and the power module are also arranged on the bottom wall of the shell. The three modes are adopted to carry out effective and high-precision monitoring on hydrogen leakage in parallel, hydrogen state information can be obtained more accurately, and each mode adopts data processing, signal processing and other modes superior to the prior art to improve the hydrogen leakage judgment accuracy.

Description

Technical Field

[0001] The invention relates to the field of testing, and in particular to an online monitoring device for pipeline hydrogen leakage. Background Art

[0002] At room temperature and pressure, hydrogen is a highly flammable, colorless, transparent, odorless and tasteless gas. At room temperature, the properties of hydrogen are very stable and it is not easy to react chemically with other substances. But when the conditions change (such as ignition, heating, use of catalysts, etc.), the situation is different. For example, hydrogen has strong activity after being adsorbed by metals such as palladium or platinum (especially when adsorbed by palladium). Metal palladium has a strong adsorption effect on hydrogen. When the volume fraction in the air is 4%-75%, it can cause combustion and explosion when encountering a fire source.

[0003] In the existing technology, there are two main ways to detect pipeline hydrogen leakage: one is to directly detect hydrogen leaking to the outside through a detector installed outside the pipeline (such as an acoustic sensor, optical fiber or cable sensor); the other is to indirectly determine whether the pipeline is leaking by detecting the operating parameters of the hydrogen pipeline (pressure and flow, etc.). However, these sensors cannot accurately determine the situation of pipeline hydrogen leakage. Summary of the invention

[0004] Therefore, in order to overcome the above problems, the present invention provides an online monitoring device for pipeline hydrogen leakage, which has low cost, accurate test results, is easy to install, and is not easy to damage.

[0005] The pipeline hydrogen leakage online monitoring device provided by the present invention includes a shell, a temperature monitoring module, a laser light source, a laser receiving unit, a backup monitoring module, a hydrogen monitoring module, a reflective lens, and a power module, wherein the temperature monitoring module, the backup monitoring module, and the hydrogen monitoring module are all arranged on the first side wall of the shell, the laser light source is arranged on the second side wall of the shell, the first side wall and the second side wall of the shell are adjacent, a plurality of air inlets are arranged on the third side wall of the shell, the third side wall and the second side wall of the shell are opposite, the laser receiving unit is arranged on the bottom wall of the shell, and the reflective lens and the power module are also arranged on the bottom wall of the shell.

[0006] The temperature monitoring module is provided with a temperature monitoring sensor and a signal conditioning circuit, the hydrogen monitoring module is provided with a hydrogen monitoring sensor, and the spare monitoring module is used to connect other sensing devices such as humidity monitoring sensors and vibration monitoring sensors.

[0007] The laser receiving unit receives the laser reflected by the reflective lens and converts the optical signal into an electrical signal. The laser receiving unit is connected to the communication device. The laser receiving unit transmits the received electrical signal to the microcontroller through the communication device. The microcontroller marks the received signal of the laser receiving unit as a first signal. A first threshold range is stored in the microcontroller. If the first signal received by the microcontroller exceeds the first threshold range, a high-level signal is output to the AND gate circuit inside the microcontroller, otherwise a low-level signal is output.

[0008] The hydrogen monitoring sensor is also connected to the microcontroller through the communication device. The hydrogen monitoring sensor is used to detect the hydrogen concentration signal. The hydrogen monitoring sensor transmits the detected electrical signal to the microcontroller through the communication device. The microcontroller marks the received signal of the hydrogen monitoring sensor as a second signal. The microcontroller stores a second threshold range. If the second signal received by the microcontroller exceeds the second threshold range, a high-level signal is output to the AND gate circuit inside the microcontroller, otherwise a low-level signal is output.

[0009] The temperature monitoring sensor is used to collect the temperature signal at the detection site. The output end of the temperature monitoring sensor is connected to the signal conditioning circuit, and the signal conditioning circuit is also connected to the microcontroller through a communication device. The temperature monitoring sensor transmits the detected electrical signal to the microcontroller through the signal conditioning circuit through the communication device. The microcontroller marks the received signal of the temperature monitoring sensor as a third signal. An abnormal temperature detection unit is provided in the microcontroller. The abnormal temperature detection unit analyzes the third signal. If it is determined that an abnormal temperature signal occurs, a high-level signal is output to the AND gate circuit inside the microcontroller, otherwise a low-level signal is output.

[0010] The AND gate circuit inside the microcontroller starts to operate after receiving the complete three high / low level signals. If all three signals are high level signals, the AND gate circuit outputs a high level signal to the remote control end, and the remote control turns on the alarm mode to indicate hydrogen leakage. If any one of the three signals is a low level signal, the AND gate circuit outputs a low level signal to the remote control end, and the remote control end obtains temperature data, hydrogen data, laser receiving unit data and spare test module data for recording.

[0011] The rate of change of the third signal can be calculated using formula (1): (1) In formula (1) Indicates the current temperature signal. Indicates the temperature signal at the last sampling moment.

[0012] Formula (2) can be used to calculate the acquisition probability of the temperature signal: (2) In formula (2), Indicates the number of temperature signals actually collected. Indicates the total number of collections.

[0013] The characteristic degree of abnormal temperature signal is calculated based on the obtained results: (3) In formula (3), represents the actual eigenvalue, represents the normal threshold, Indicates the deformity threshold.

[0014] If the actual characteristic value exceeds the normal threshold but is lower than the abnormal threshold, the characteristic degree of the signal is between normal and abnormal. If the actual characteristic value exceeds the abnormal threshold, the characteristic degree of the signal is 1, indicating that the signal is an abnormal temperature signal.

[0015] Formula (4) can be used to calculate the similarity between abnormal temperature signals: + (4) In formula (4), Indicates the characteristic degree of abnormal temperature signal 1, It represents the characteristic of the abnormal temperature signal 2. The similarity value is between 0 and 1. The closer it is to 1, the higher the similarity between the two abnormal temperature signals is. The closer it is to 0, the lower the similarity between the two abnormal temperature signals is. The similarity threshold is set to 0.5. If H>0.5, it means that two consecutive signals are abnormal temperature signals, that is, the temperature signal is abnormal, and a high-level signal is output to the AND gate circuit inside the microcontroller, otherwise a low-level signal is output.

[0016] The signal conditioning circuit is a first signal processing circuit, which includes resistors R1-R7, capacitors C1-C6, a field effect transistor Q1, and an operational amplifier, wherein the output end of the temperature monitoring sensor is connected to one end of the capacitor C4, the other end of the capacitor C4 is connected to the gate of the field effect transistor Q1, one end of the resistor R2 is connected to the gate of the field effect transistor Q1, the other end of the resistor R2 is grounded, one end of the resistor R3 is connected to the source of the field effect transistor Q1, the other end of the resistor R3 is grounded, one end of the resistor R1 is connected to one end of the resistor R3, the other end of the resistor R1 is grounded, one end of the resistor R9 and the capacitor C6 connected in series is connected to one end of the resistor R4, the other end of the resistor R9 and the capacitor C6 connected in series is grounded, one end of the resistor R4 is connected to the source of the field effect transistor Q1, one end of the capacitor C5 is grounded, and the other end of the capacitor C5 is connected to a +5V power supply, One end of resistor R6 is connected to the other end of capacitor C5, the other end of resistor R6 is connected to the drain of field effect transistor Q1, one end of capacitor C2 is connected to the other end of resistor R6, the other end of capacitor C2 is connected to the inverting end of the operational amplifier, one end of resistor R5 is connected to a +2.5V power supply, the other end of resistor R5 is connected to the non-inverting end of the operational amplifier, one power supply end of the operational amplifier is grounded, the other power supply end of the operational amplifier is connected to a +5V power supply, one end of capacitor C1 is grounded, the other end of capacitor C1 is connected to a +5V power supply, one end of capacitor C3 and resistor R7 connected in parallel is connected to the inverting end of the operational amplifier, the other end of capacitor C3 and resistor R7 connected in parallel is connected to the output end of the operational amplifier, the other end of resistor R4 is connected to the output end of the operational amplifier, and the output end of the operational amplifier is connected to the abnormal temperature detection unit in the microcontroller through a communication device.

[0017] The signal conditioning circuit can also be a second signal processing circuit, which includes resistors R1-R8, capacitors C1-C5, a first operational amplifier, and a second operational amplifier, wherein the output end of the temperature monitoring sensor is connected to one end of the resistor R1, the other end of the resistor R1 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to a +2.5V power supply, one end of the resistor R7 is connected to the other end of the resistor R2, the other end of the resistor R7 is connected to the non-inverting input end of the first operational amplifier, one end of the capacitor C1 is connected to the other end of the resistor R1, the other end of the capacitor C1 is connected to the inverting input end of the first operational amplifier, one end of the capacitor C2 is connected to one end of the capacitor C1, the other end of the capacitor C2 is connected to the output end of the first operational amplifier, one end of the resistor R3 is connected to the other end of the capacitor C2, the other end of the resistor R3 is connected to the inverting input end of the first operational amplifier, and a power supply end of the first operational amplifier is grounded. The other power supply terminal of the first operational amplifier is connected to the +5V power supply, one end of the capacitor C5 is grounded, and the other end of the capacitor C5 is connected to the +5V power supply, the output end of the first operational amplifier is connected to one end of the resistor R4, the other end of the resistor R4 is connected to one end of the resistor R5, and the other end of the resistor R5 is connected to the +2.5V power supply, one end of the resistor R8 is connected to the other end of the resistor R5, and the other end of the resistor R8 is connected to the non-inverting input terminal of the second operational amplifier, one end of the capacitor C3 is connected to the other end of the resistor R4, and the other end of the capacitor C3 is connected to the inverting input terminal of the second operational amplifier, one end of the capacitor C4 is connected to one end of the capacitor C3, and the other end of the capacitor C4 is connected to the output end of the second operational amplifier, one end of the resistor R6 is connected to the other end of the capacitor C4, and the other end of the resistor R6 is connected to the inverting input terminal of the second operational amplifier, and the output end of the second operational amplifier is connected to the abnormal temperature detection unit in the microcontroller through the communication device.

[0018] The present invention adopts three modes in parallel to monitor hydrogen leakage effectively and with high precision, and can obtain hydrogen status information more accurately. Moreover, each mode adopts data processing, signal processing and other methods that are superior to the existing technology to improve the accuracy of hydrogen leakage judgment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a diagram showing the internal structure of the on-line monitoring device for pipeline hydrogen leakage of the present invention; Figure 2 This is a schematic diagram of the hydrogen leakage online monitoring principle of the present invention; Figure 3 is a first signal processing circuit of the present invention; Figure 4 is a second signal processing circuit of the present invention; Figure 5 This is the mobile phone alarm display interface of the present invention.

[0020] Figure numerals: 1-housing, 2-temperature monitoring module, 3-laser light source, 4-laser receiving unit, 5-backup monitoring module, 6-hydrogen monitoring module, 7-reflecting lens, 8-power module. DETAILED DESCRIPTION

[0021] The online monitoring device for pipeline hydrogen leakage provided by the present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0022] First, the same marks involved in the embodiments and drawings represent the same or similar components or structural features. Secondly, when describing that a component is disposed on another component, it means that one component is directly disposed on another component, or one component is indirectly disposed on another component, that is, one or more components are disposed between the two components. When describing that a component is directly disposed on another component, it means that there are no other components between the two components.

[0023] like Figure 1-2 As shown, the online monitoring device for pipeline hydrogen leakage of the present invention includes a shell 1, a temperature monitoring module 2, a laser light source 3, a laser receiving unit 4, a backup monitoring module 5, a hydrogen monitoring module 6, a reflective lens 7, and a power module 8, wherein the temperature monitoring module 2, the backup monitoring module 5, and the hydrogen monitoring module 6 are all arranged on the first side wall of the shell 1, the laser light source 3 is arranged on the second side wall of the shell 1, the first side wall and the second side wall of the shell 1 are adjacent, a plurality of air inlets are arranged on the third side wall of the shell 1, the third side wall and the second side wall of the shell 1 are opposite, the laser receiving unit 4 is arranged on the bottom wall of the shell 1, and the reflective lens 7 and the power module 8 are also arranged on the bottom wall of the shell 1.

[0024] In this embodiment, a moving device may be provided at the bottom of the housing 1 to facilitate continuous and motion testing.

[0025] The temperature monitoring module 2 is provided with a temperature monitoring sensor and a signal conditioning circuit, the hydrogen monitoring module 6 is provided with a hydrogen monitoring sensor, and the standby monitoring module 5 is used to connect other sensing devices such as a humidity monitoring sensor and a vibration monitoring sensor.

[0026] Gas molecules have characteristic absorption peaks. When a laser beam of a specific wavelength passes through a gas medium, the laser intensity will attenuate according to gas absorption. The degree of attenuation is quantitatively related to the content of the gas being measured. According to the characteristics of the absorption spectrum curve of hydrogen molecules, it has a strong absorption peak at 2120nm. Therefore, 2120nm is selected as the laser light source 3, and the laser receiving unit 4 receives the laser reflected by the reflective lens 7 and converts the optical signal into an electrical signal. The laser receiving unit 4 is connected to a communication device, and the laser receiving unit 4 transmits the received electrical signal to the microcontroller through the communication device. The microcontroller marks the received signal of the laser receiving unit 4 as a first signal. The microcontroller stores a first threshold range. If the first signal received by the microcontroller exceeds the first threshold range, a high-level signal is output to the AND gate circuit inside the microcontroller, otherwise a low-level signal is output.

[0027] The hydrogen monitoring sensor is also connected to the microcontroller through the communication device. The hydrogen monitoring sensor is used to detect the hydrogen concentration signal. The hydrogen monitoring sensor transmits the detected electrical signal to the microcontroller through the communication device. The microcontroller marks the received signal of the hydrogen monitoring sensor as a second signal. The microcontroller stores a second threshold range. If the second signal received by the microcontroller exceeds the second threshold range, a high-level signal is output to the AND gate circuit inside the microcontroller, otherwise a low-level signal is output.

[0028] When the hydrogen monitoring sensor performs hydrogen concentration detection, a driving voltage is first applied to the hydrogen monitoring sensor through a simple driving circuit. After preheating, the hydrogen monitoring sensor starts to work normally. When there is only clean air at the detection site, the conductivity of the hydrogen monitoring sensor is low. When the hydrogen concentration at the detection site gradually increases, the conductivity of the hydrogen monitoring sensor will gradually decrease, and the change in sensor conductivity will be converted into a voltage change signal corresponding to the hydrogen gas concentration through a simple circuit.

[0029] The hydrogen monitoring sensor uses tin dioxide as the gas-sensitive material and has a high sensitivity to hydrogen concentration within the concentration range of 0.1‰ to 1‰. The hydrogen monitoring sensor drive circuit unit uses a 24V DC power supply. By connecting an adjustable resistor in series with the hydrogen monitoring sensor, a 24V working voltage is provided to the hydrogen monitoring sensor while a 5V heating voltage is provided to the sensor heater.

[0030] When hydrogen leakage occurs, the temperature will also change accordingly. The temperature monitoring sensor is used to collect the temperature signal of the detection site. The output end of the temperature monitoring sensor is connected to the signal conditioning circuit, and the signal conditioning circuit is also connected to the microcontroller through a communication device. The temperature monitoring sensor transmits the detected electrical signal to the microcontroller through the communication device via the signal conditioning circuit. The microcontroller marks the received signal of the temperature monitoring sensor as a third signal. An abnormal temperature detection unit is provided in the microcontroller. The abnormal temperature detection unit analyzes the third signal. If it is determined that an abnormal temperature signal occurs, a high-level signal is output to the AND gate circuit inside the microcontroller, otherwise a low-level signal is output.

[0031] In this embodiment, in an actual monitoring environment, the rate of change of the third signal can be calculated using formula (1): (1) In formula (1) Indicates the current temperature signal. Indicates the temperature signal at the last sampling moment.

[0032] This formula can be used to calculate the change of the abnormal temperature signal at two adjacent moments. If the change rate is positive, it means that the abnormal temperature signal is increasing. If the change rate is negative, it means that the abnormal temperature signal is decreasing. If the change rate is zero, it means that the abnormal temperature signal has not changed.

[0033] The calculation of the rate of change needs to take into account factors in the acquisition environment, such as humidity, which may affect the abnormal temperature signal. Therefore, these factors need to be taken into account when calculating the rate of change. The acquisition probability of the temperature signal can be calculated using formula (2): (2) In formula (2), Indicates the number of temperature signals actually collected. Indicates the total number of collections.

[0034] The characteristic degree of abnormal temperature signal is calculated based on the obtained results: (3) In formula (3), represents the actual eigenvalue, represents the normal threshold, Indicates the deformity threshold.

[0035] If the actual characteristic value exceeds the normal threshold but is lower than the abnormal threshold, the characteristic degree of the signal is between normal and abnormal. If the actual characteristic value exceeds the abnormal threshold, the characteristic degree of the signal is 1, indicating that the signal is an abnormal temperature signal.

[0036] Formula (4) can be used to calculate the similarity between abnormal temperature signals: + (4) In formula (4), Indicates the characteristic degree of abnormal temperature signal 1, Indicates the characteristic degree of abnormal temperature signal 2.

[0037] The similarity value is between 0 and 1. The closer it is to 1, the higher the similarity between the two abnormal temperature signals. The closer it is to 0, the lower the similarity between the two abnormal temperature signals.

[0038] In this embodiment, the similarity threshold is set to 0.5. If H>0.5, it means that two consecutive signals are both abnormal temperature signals, that is, the temperature signal is abnormal, and a high-level signal is output to the AND gate circuit inside the microcontroller, otherwise a low-level signal is output.

[0039] like Figure 3 As shown, the signal conditioning circuit is the first signal processing circuit.

[0040] The first signal processing circuit includes resistors R1-R7, capacitors C1-C6, a field effect transistor Q1, and an operational amplifier, wherein the output end of the temperature monitoring sensor is connected to one end of the capacitor C4, the other end of the capacitor C4 is connected to the gate of the field effect transistor Q1, one end of the resistor R2 is connected to the gate of the field effect transistor Q1, the other end of the resistor R2 is grounded, one end of the resistor R3 is connected to the source of the field effect transistor Q1, the other end of the resistor R3 is grounded, one end of the resistor R1 is connected to one end of the resistor R3, the other end of the resistor R1 is grounded, one end of the resistor R9 and the capacitor C6 are connected in series to one end of the resistor R4, the other end of the resistor R9 and the capacitor C6 are grounded, one end of the resistor R4 is connected to the source of the field effect transistor Q1, one end of the capacitor C5 is grounded, the other end of the capacitor C5 is connected to the +5V power supply, one end of the resistor R6 is connected to the The other end of capacitor C5 is connected, the other end of resistor R6 is connected to the drain of field effect transistor Q1, one end of capacitor C2 is connected to the other end of resistor R6, the other end of capacitor C2 is connected to the inverting end of the operational amplifier, one end of resistor R5 is connected to a +2.5V power supply, the other end of resistor R5 is connected to the non-inverting end of the operational amplifier, one power supply end of the operational amplifier is grounded, the other power supply end of the operational amplifier is connected to a +5V power supply, one end of capacitor C1 is grounded, the other end of capacitor C1 is connected to a +5V power supply, one end of capacitor C3 and resistor R7 connected in parallel is connected to the inverting end of the operational amplifier, the other end of capacitor C3 and resistor R7 connected in parallel is connected to the output end of the operational amplifier, the other end of resistor R4 is connected to the output end of the operational amplifier, and the output end of the operational amplifier is connected to the abnormal temperature detection unit in the microcontroller through a communication device.

[0041] Environmental noise and the interference of the transmission process on weak signals are factors that cannot be ignored. In the entire circuit system, the noise of the first signal processing circuit directly affects the overall noise coefficient. Therefore, it is crucial for the first signal processing circuit to have low noise and strong anti-interference capabilities. The first signal processing circuit designed by the present invention adopts a low-noise operational amplifier combined with a field-effect transistor to achieve impedance matching and 26dB fixed gain amplification of the first signal processing circuit. Impedance matching is to obtain the maximum target signal from the previous receiving array element. Therefore, the equivalent input impedance of the first signal processing circuit must be much larger than the output impedance of the receiving array element.

[0042] N-channel junction field effect transistors are an ideal choice due to their high input impedance and low noise characteristics. Adding this junction field effect transistor to the front end of the inverting amplifier circuit can effectively meet the performance requirements for high input impedance. The first signal processing circuit optimizes the signal processing process and improves the signal-to-noise ratio to ensure signal clarity and stability.

[0043] Analysis of the principle of the first signal processing circuit: This circuit design combines the basic amplification function of the field effect tube with the inverting amplifier circuit to achieve efficient signal processing. Among them, the ratio of the parallel resistance of resistor R4 to R1 and R9 determines the amplification factor of the inverting amplifier circuit, thereby ensuring the effective amplification of the signal. In addition, the filter RC circuit composed of capacitor C3 and resistor R7 effectively suppresses unstable phenomena such as self-oscillation and ensures the stability of the circuit. At the same time, the two capacitors C2 and C4 play a role in blocking the DC component in the analog signal, avoiding the interference of the DC component on the required signal, ensuring the purity and accurate transmission of the signal. This circuit is powered by a single power supply of 5 V and uses a 2.5 V reference voltage to achieve voltage lift. Capacitors C1 and C5 are bypass capacitors, which play a key role and effectively isolate the noise at the power supply end to prevent it from having an adverse effect on the circuit performance.

[0044] like Figure 4 As shown, the signal conditioning circuit can also be a second signal processing circuit.

[0045] The second signal processing circuit includes resistors R1-R8, capacitors C1-C5, a first operational amplifier, and a second operational amplifier, wherein the output end of the temperature monitoring sensor is connected to one end of the resistor R1, the other end of the resistor R1 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to a +2.5V power supply, one end of the resistor R7 is connected to the other end of the resistor R2, the other end of the resistor R7 is connected to the non-inverting input end of the first operational amplifier, one end of the capacitor C1 is connected to the other end of the resistor R1, the other end of the capacitor C1 is connected to the inverting input end of the first operational amplifier, one end of the capacitor C2 is connected to one end of the capacitor C1, the other end of the capacitor C2 is connected to the output end of the first operational amplifier, one end of the resistor R3 is connected to the other end of the capacitor C2, the other end of the resistor R3 is connected to the inverting input end of the first operational amplifier, a power supply end of the first operational amplifier is grounded, and the other end of the first operational amplifier is grounded. The power supply terminal is connected to a +5V power supply, one end of the capacitor C5 is grounded, and the other end of the capacitor C5 is connected to the +5V power supply. The output end of the first operational amplifier is connected to one end of the resistor R4, the other end of the resistor R4 is connected to one end of the resistor R5, and the other end of the resistor R5 is connected to the +2.5V power supply. One end of the resistor R8 is connected to the other end of the resistor R5, and the other end of the resistor R8 is connected to the non-inverting input end of the second operational amplifier. One end of the capacitor C3 is connected to the other end of the resistor R4, and the other end of the capacitor C3 is connected to the inverting input end of the second operational amplifier. One end of the capacitor C4 is connected to one end of the capacitor C3, and the other end of the capacitor C4 is connected to the output end of the second operational amplifier. One end of the resistor R6 is connected to the other end of the capacitor C4, and the other end of the resistor R6 is connected to the inverting input end of the second operational amplifier. The output end of the second operational amplifier is connected to the abnormal temperature detection unit in the microcontroller through the communication device.

[0046] To avoid interference from signals outside the required frequency range, only signals within a specific frequency range are allowed to pass. A second signal processing circuit with a frequency selection function is used to filter out or attenuate signals outside the frequency range. The second signal processing circuit has a passband range of 380~420kHz. In order to meet the demand for high frequency resolution, the second signal processing circuit selects a fourth-order structure, which can reduce the consumption of computing resources while maintaining the required accuracy.

[0047] Another advantage of the second signal processing circuit is its adaptability to different environmental noise conditions, especially when the background noise is complex or constantly changing. This makes the second signal processing circuit extremely useful in practical applications, such as temperature testing in a noisy environment. In order to ensure the flatness within the passband, this design uses function approximation, which has the maximum smoothness between the passband and the stopband, making the slope of the frequency response curve the most gentle, which helps to reduce the phase distortion and ringing effect introduced in the signal processing process.

[0048] The second signal processing circuit has a center frequency of 400 kHz and a bandwidth of 40 kHz (-1dB bandwidth), and has low noise and low distortion characteristics.

[0049] The AND gate circuit inside the microcontroller starts to operate after receiving the complete three high / low level signals. If all three signals are high level signals, the AND gate circuit outputs a high level signal to the remote control terminal, and the remote control terminal turns on the alarm mode. Figure 5 As shown, hydrogen leakage is displayed. If any one of the three signals is a low-level signal, the AND gate circuit outputs a low-level signal to the remote control end, and the remote control end obtains temperature data, hydrogen data, laser receiving unit data, and spare test module data for recording.

[0050] The three modes are used in parallel to monitor hydrogen leaks effectively and with high precision, which can obtain hydrogen status information more accurately, thereby improving the accuracy of hydrogen leak judgment.

[0051] Finally, it is stated again that the constituent elements / components described in the aforementioned embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of the present invention. Replacements or changes to other equivalent components should be within the scope of protection of the present invention.

Claims

1. An online monitoring device for pipeline hydrogen leakage, characterized in that: The pipeline hydrogen leakage online monitoring device comprises a housing (1), a temperature monitoring module (2), a laser light source (3), a laser receiving unit (4), a backup monitoring module (5), a hydrogen monitoring module (6), a reflective lens (7), and a power module (8), wherein the temperature monitoring module (2), the backup monitoring module (5), and the hydrogen monitoring module (6) are all arranged on a first side wall of the housing (1), the laser light source (3) is arranged on a second side wall of the housing (1), the first side wall and the second side wall of the housing (1) are adjacent, a plurality of air inlets are arranged on the third side wall of the housing (1), the third side wall and the second side wall of the housing (1) are opposite, the laser receiving unit (4) is arranged on the bottom wall of the housing (1), and the reflective lens (7) and the power module (8) are also arranged on the bottom wall of the housing (1); The temperature monitoring module (2) is provided with a temperature monitoring sensor and a signal conditioning circuit, the hydrogen monitoring module (6) is provided with a hydrogen monitoring sensor, and the standby monitoring module (5) is used to connect other sensing devices such as a humidity monitoring sensor and a vibration monitoring sensor; The laser receiving unit (4) receives the laser reflected by the reflective lens (7) and converts the optical signal into an electrical signal. The laser receiving unit (4) is connected to a communication device. The laser receiving unit (4) transmits the received electrical signal to a microcontroller via the communication device. The microcontroller marks the signal received by the laser receiving unit (4) as a first signal. A first threshold range is stored in the microcontroller. If the first signal received by the microcontroller exceeds the first threshold range, a high level signal is output to an AND gate circuit inside the microcontroller. Otherwise, a low level signal is output. The hydrogen monitoring sensor is also connected to the microcontroller through the communication device. The hydrogen monitoring sensor is used to detect the hydrogen concentration signal. The hydrogen monitoring sensor transmits the detected electrical signal to the microcontroller through the communication device. The microcontroller marks the received signal of the hydrogen monitoring sensor as a second signal. The microcontroller stores a second threshold range. If the second signal received by the microcontroller exceeds the second threshold range, a high level signal is output to the AND gate circuit inside the microcontroller, otherwise a low level signal is output; The temperature monitoring sensor is used to collect the temperature signal of the detection site. The output end of the temperature monitoring sensor is connected to the signal conditioning circuit. The signal conditioning circuit is also connected to the microcontroller through the communication device. The temperature monitoring sensor transmits the detected electrical signal to the microcontroller through the communication device via the signal conditioning circuit. The microcontroller marks the received signal of the temperature monitoring sensor as a third signal. An abnormal temperature detection unit is provided in the microcontroller. The abnormal temperature detection unit analyzes the third signal. If it is determined that an abnormal temperature signal occurs, a high-level signal is output to the AND gate circuit inside the microcontroller, otherwise a low-level signal is output; The AND gate circuit inside the microcontroller starts to operate after receiving the complete three high / low level signals. If all three signals are high level signals, the AND gate circuit outputs a high level signal to the remote control end, and the remote control turns on the alarm mode to indicate hydrogen leakage. If any one of the three signals is a low level signal, the AND gate circuit outputs a low level signal to the remote control end, and the remote control end obtains temperature data, hydrogen data, laser receiving unit data and spare test module data for recording.

2. The on-line monitoring device for pipeline hydrogen leakage according to claim 1 is characterized in that: The rate of change of the third signal can be calculated using formula (1): （1） In formula (1) Indicates the current temperature signal, Indicates the temperature signal at the last sampling moment; Formula (2) can be used to calculate the acquisition probability of the temperature signal: （2） In formula (2), Indicates the number of temperature signals actually collected. Indicates the total number of acquisitions; The characteristic degree of abnormal temperature signal is calculated based on the obtained results: （3） In formula (3), represents the actual eigenvalue, represents the normal threshold, represents the deformity threshold; If the actual characteristic value exceeds the normal threshold but is lower than the abnormal threshold, the characteristic degree of the signal is between normal and abnormal. If the actual characteristic value exceeds the abnormal threshold, the characteristic degree of the signal is 1, indicating that the signal is an abnormal temperature signal. Formula (4) can be used to calculate the similarity between abnormal temperature signals: + （4） In formula (4), Indicates the characteristic degree of abnormal temperature signal 1, It represents the characteristic of the abnormal temperature signal 2. The similarity value is between 0 and 1. The closer it is to 1, the higher the similarity between the two abnormal temperature signals is. The closer it is to 0, the lower the similarity between the two abnormal temperature signals is. The similarity threshold is set to 0.

5. If H>0.5, it means that two consecutive signals are abnormal temperature signals, that is, the temperature signal is abnormal, and a high-level signal is output to the AND gate circuit inside the microcontroller, otherwise a low-level signal is output.

3. The on-line monitoring device for pipeline hydrogen leakage according to claim 1, characterized in that: The signal conditioning circuit is a first signal processing circuit, which includes resistors R1-R7, capacitors C1-C6, a field effect transistor Q1, and an operational amplifier, wherein the output end of the temperature monitoring sensor is connected to one end of the capacitor C4, the other end of the capacitor C4 is connected to the gate of the field effect transistor Q1, one end of the resistor R2 is connected to the gate of the field effect transistor Q1, the other end of the resistor R2 is grounded, one end of the resistor R3 is connected to the source of the field effect transistor Q1, the other end of the resistor R3 is grounded, one end of the resistor R1 is connected to one end of the resistor R3, the other end of the resistor R1 is grounded, one end of the resistor R9 and the capacitor C6 connected in series is connected to one end of the resistor R4, the other end of the resistor R9 and the capacitor C6 connected in series is grounded, one end of the resistor R4 is connected to the source of the field effect transistor Q1, one end of the capacitor C5 is grounded, and the other end of the capacitor C5 is connected to a +5V power supply, One end of resistor R6 is connected to the other end of capacitor C5, the other end of resistor R6 is connected to the drain of field effect transistor Q1, one end of capacitor C2 is connected to the other end of resistor R6, the other end of capacitor C2 is connected to the inverting end of the operational amplifier, one end of resistor R5 is connected to a +2.5V power supply, the other end of resistor R5 is connected to the non-inverting end of the operational amplifier, one power supply end of the operational amplifier is grounded, the other power supply end of the operational amplifier is connected to a +5V power supply, one end of capacitor C1 is grounded, the other end of capacitor C1 is connected to a +5V power supply, one end of capacitor C3 and resistor R7 connected in parallel is connected to the inverting end of the operational amplifier, the other end of capacitor C3 and resistor R7 connected in parallel is connected to the output end of the operational amplifier, the other end of resistor R4 is connected to the output end of the operational amplifier, and the output end of the operational amplifier is connected to the abnormal temperature detection unit in the microcontroller through a communication device.

4. The on-line monitoring device for pipeline hydrogen leakage according to claim 1, characterized in that: The signal conditioning circuit is a second signal processing circuit, and the second signal processing circuit includes resistors R1-R8, capacitors C1-C5, a first operational amplifier, and a second operational amplifier, wherein the output end of the temperature monitoring sensor is connected to one end of the resistor R1, the other end of the resistor R1 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to a +2.5V power supply, one end of the resistor R7 is connected to the other end of the resistor R2, the other end of the resistor R7 is connected to the non-inverting input end of the first operational amplifier, one end of the capacitor C1 is connected to the other end of the resistor R1, the other end of the capacitor C1 is connected to the inverting input end of the first operational amplifier, one end of the capacitor C2 is connected to one end of the capacitor C1, the other end of the capacitor C2 is connected to the output end of the first operational amplifier, one end of the resistor R3 is connected to the other end of the capacitor C2, the other end of the resistor R3 is connected to the inverting input end of the first operational amplifier, a power supply end of the first operational amplifier is grounded, and the first The other power supply terminal of the operational amplifier is connected to the +5V power supply, one end of the capacitor C5 is grounded, and the other end of the capacitor C5 is connected to the +5V power supply, the output end of the first operational amplifier is connected to one end of the resistor R4, the other end of the resistor R4 is connected to one end of the resistor R5, and the other end of the resistor R5 is connected to the +2.5V power supply, one end of the resistor R8 is connected to the other end of the resistor R5, and the other end of the resistor R8 is connected to the non-inverting input terminal of the second operational amplifier, one end of the capacitor C3 is connected to the other end of the resistor R4, and the other end of the capacitor C3 is connected to the inverting input terminal of the second operational amplifier, one end of the capacitor C4 is connected to one end of the capacitor C3, and the other end of the capacitor C4 is connected to the output end of the second operational amplifier, one end of the resistor R6 is connected to the other end of the capacitor C4, and the other end of the resistor R6 is connected to the inverting input terminal of the second operational amplifier, and the output end of the second operational amplifier is connected to the abnormal temperature detection unit in the microcontroller through the communication device.

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