CN217277915U - A gas leak detection system - Google Patents

Abstract

The present application discloses a gas leak detection system. The gas leak detection system includes a signal acquisition optical system, a signal processing module and an alarm; the signal acquisition optical system acquires the high signal-to-noise ratio imaging and diffraction characteristics of the gas light passing through the detection area, and the signal processing module analyzes the collected signals in real time And judgment, the judgment result is transmitted to the alarm by comparing with the characteristics when there is no leakage, once the gas leakage is detected, the alarm system is triggered immediately. The present application has the characteristics of large detection range, high precision and fast response, which can significantly improve the leak detection efficiency and greatly reduce the possible harm caused by hydrogen leakage.

Description

A gas leak detection system

technical field

The present application relates to the field of gas leak detection, in particular to a hydrogen gas leak detection system.

Background technique

In the context of energy transition, the development of hydrogen energy has become the consensus of developed economies. As the most promising secondary energy in the 21st century, hydrogen energy has the characteristics of abundant sources, high thermal efficiency and clean combustion. It can replace fossil fuels such as coal, oil and natural gas. ” goals are significant.

Photoelectric hydrogen production has always attracted attention because it can generate green hydrogen (hydrogen produced by using renewable energy to produce hydrogen without carbon emissions in the process). However, hydrogen has the characteristics of low viscosity and easy gasification. Once leaked from hydrogen storage tanks or hydrogen pipelines, it will quickly mix with air to form flammable and explosive vapor clouds. The explosion (volume fraction of 4% to 75%) and detonation limit (volume fraction of 18.3% to 59%) of hydrogen in air are wide, and the detonation velocity is extremely high (1480m/s to 2150m/s). Therefore, once the vapor cloud encounters the ignition source and produces deflagration or detonation, it will cause serious damage to the photovoltaic hydrogen production equipment, resulting in greater economic losses and casualties. Hydrogen leakage often occurs at the connections of valves and flanges of hydrogen pipelines. Therefore, it is of great significance for the safe and stable operation of the photoelectric hydrogen production system to quickly and accurately detect the leakage of the hydrogen transmission pipeline in the process of photoelectric hydrogen production, and take corresponding fire protection measures in time.

Traditional gas leak detection methods, such as using gas sensors, have the disadvantages of small detection range and low accuracy.

Utility model content

In order to solve the problems that the detection range of the above-mentioned gas leak detection is small and the sensitivity is not high, the application proposes the following technical solutions:

A gas leak detection system comprising:

Signal acquisition optical system, signal processing module and alarm;

The signal acquisition optical system includes: a light source, a spectroscopic element, a 4f Fourier system, a spectrum processor and a dispersion element; the spectrum processor is arranged on the spectrum plane in the 4f Fourier system, and the light emitted by the light source passes through the The spectroscopic element is divided into two paths. One path passes through the 4f Fourier system and transmits the imaging information containing the high signal-to-noise ratio of the gas in the detection area to the signal processing module; The diffraction information is transmitted to the signal processing module;

The signal processing module analyzes and determines the collected high signal-to-noise ratio imaging and diffraction characteristics in real time; and transmits the determination result to the connected alarm.

The spectrum processor shown is a filter for outputting spectrum information, filtering out high-frequency information, and retaining low-frequency information with a strong signal-to-noise ratio; the image-side focal plane of the first Fourier lens is the spectrum plane of the entire system Or called transform plane. When coherent parallel light is incident on the object placed on the focal plane of the object side of the first Fourier lens, the spectrum of the object will appear on the spectrum plane, and the image will be imaged on the focal plane of the image side of the second Fourier lens. The transformation process of the 4f Fourier system realizes spectral analysis of optical information and processing in the frequency domain. Adding filters to the spectrum plane can prevent information of certain frequencies from passing through, or introduce certain phase changes to certain frequencies, and can extract certain information as required, transform the structure of the image, and obtain the desired output image. It overcomes the shortcomings of small detection range and low precision of traditional gas leak detection methods such as using gas sensor for leak detection.

Preferably, the light splitting element includes: a semi-transparent and semi-reflective element and a light splitting prism.

Preferably, the dispersive element includes: a grating and a prism.

Preferably, the light source is a point light source, the light intensity emitted by the light source is lower than the ignition energy of the gas to be detected, and the light emitted by the point light source is collimated and beam-expanded and then incident on the spectroscopic element.

Preferably, the gas to be detected includes: hydrogen and natural gas.

Preferably, the 4f Fourier system includes: a first Fourier lens and a second Fourier lens, wherein the image-side focus of the first Fourier lens is set at the object-side focus of the second Fourier lens , and the two lenses are placed coaxially.

Preferably, the gas leak detection system is characterized in that:

The signal processing module analyzes the collected high signal-to-noise ratio imaging and diffraction characteristics in real time and determines whether there is gas leakage information, and transmits the result to the connected alarm. The gas leakage information includes: whether the gas leaks and/or leaks Gas is thick.

An embodiment of the present application provides a gas leak detection method, which is based on the above-mentioned gas leak detection system, and the gas leak detection method includes:

S1. Move the detection system to the vicinity of the gas source to be detected, that is, the gas source to be detected is located in the overlapping area of the two optical paths, so as to ensure that the optical signal of the gas passing through the detection area is collected;

S2, point the light source and collect high signal-to-noise ratio imaging and diffraction features, and transmit the collected information to the signal processing module;

S3. The signal processing module processes the received information and determines whether gas leakage occurs.

Preferably, after this step S3, it also includes:

When it is determined that gas leakage occurs, the determination result is output to the alarm device, and the alarm device receives and responds to the abnormal information and generates an alarm signal.

Preferably, the gas leak detection method is characterized in that:

If the gas leaks, the refractive index of the gas in the detection area will be changed, thereby affecting the high signal-to-noise ratio imaging and diffraction pattern collected in the step S2, and the collected high-signal-to-noise ratio imaging and diffraction characteristics are analyzed and determined in real time through the signal processing module. Thereby obtaining gas leakage information.

Preferably, the gas leak information includes: whether the gas leaks and the concentration of the leaked gas.

beneficial effect

The hydrogen leak detection system of the embodiment of the present application adopts an optical system for gas leak detection, and specifically includes a 4f optical system. The 4f optical system is composed of a coaxial confocal Fourier lens with the same focal length. The first Fourier lens The front focal plane of the leaf lens is the object plane; the back focal plane of the first Fourier lens (or the front focal plane of the second Fourier lens) is the spectral plane of the entire system or called the transformation plane. With coherent parallel light incident on an object placed on the object plane, the spectrum will appear on the spectral plane, and the image will be imaged on the image plane (back focal plane of the second Fourier lens). Modulating the spectrum improves the signal-to-noise ratio of the imaging, thereby extracting valid features. The leakage detection of the transportation pipeline in the photoelectric hydrogen production process can be carried out in a large area and in a wide range, and the leakage detection efficiency is improved. The system performs leak detection and sampling for hydrogen pipelines based on two optical paths, which improves the reliability of the detection system and greatly reduces the false alarm rate; Greatly reduces the hazards that may be caused by hydrogen leakage.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present specification or the prior art, the following briefly introduces the accompanying drawings required in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments described in this specification. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative labor.

1 is a schematic diagram of hydrogen leak detection in a photoelectric hydrogen production process according to an embodiment of the present application;

2 is a diagram of an optical detection system for hydrogen pipeline leakage according to an embodiment of the present application;

FIG. 3 is a flow chart of a method for optical detection of leaks in a hydrogen pipeline according to an embodiment of the present application.

Detailed ways

The above scheme will be further described below in conjunction with specific embodiments. It should be understood that these examples are intended to illustrate the present application and not to limit the scope of the present application. The implementation conditions used in the examples can be further adjusted such as the conditions of specific manufacturers, and the implementation conditions that are not specified are usually the conditions in routine experiments.

The present application discloses a gas leak detection system, which can be used to detect gases such as hydrogen and natural gas. Including a signal acquisition optical system, a signal processing module and an alarm; the signal acquisition optical system collects the high signal-to-noise ratio imaging and diffraction characteristics of the gas light passing through the detection area, and the signal processing module analyzes and determines the collected signals in real time. The characteristics of the leakage are compared and the judgment result is sent to the alarm. Once the gas leakage is detected, the alarm system is triggered immediately. The signal acquisition optical system is also called the signal acquisition module. When it is working, the light emitted by the point light source is divided into two paths after passing through the Fourier lens and the grating. After the lens, the spectrum processor and the Fourier lens, the high signal-to-noise ratio imaging features are collected by the receiving screen; the other is collected by the receiving screen after passing through the gas pipeline (such as hydrogen pipeline) and grating of the gas to be measured. Signal processing module: Receive the sampling feedback signal and analyze and determine the collected high signal-to-noise ratio imaging and diffraction characteristics based on the micro-control unit. Once it is determined that there is leakage (for example, it is determined that there is hydrogen leakage in the hydrogen pipeline), an alarm signal will be sent out through the alarm module immediately. The leak detection method of the detection system can detect and respond quickly to the hydrogen pipeline in real time, which greatly reduces the possible harm caused by gas (such as hydrogen) leakage. The detection mechanism of this method, taking hydrogen as an example, the leakage of hydrogen will change the refractive index of the gas in the detection area (around the hydrogen pipeline), thereby affecting the high signal-to-noise ratio imaging and diffraction pattern. The high signal-to-noise ratio imaging and diffraction characteristics are analyzed in real time, and compared with the signal under normal conditions. When the high signal-to-noise ratio imaging and diffraction characteristics are abnormal, it is determined that the detected hydrogen pipeline leaks. Two-way judgment Enhanced reliability of results.

The gas leakage detection system implemented in the present application is further described below with reference to accompanying drawings 1 and 2 and taking hydrogen as an example, wherein, Fig. 1 shows a schematic diagram of hydrogen leakage detection in the photoelectric hydrogen production process: photoelectric hydrogen production system 1, photovoltaic array 2, Photovoltaic controller 3 , water electrolysis hydrogen production system 4 , optical detection system 5 , valve 6 , hydrogen pipeline 7 , hydrogen storage tank 8 .

The photovoltaic hydrogen production system is mainly composed of a photovoltaic array 2 , a photovoltaic controller 3 and a water electrolysis device 4 . After the hydrogen is generated from the hydrogen production system, it is transported through the hydrogen transport pipeline 7 and sent to the hydrogen storage tank 8 after being pressurized. The optical detection system for hydrogen transmission pipeline leakage is shown in Figure 2, including: signal acquisition, signal processing and alarm devices, specifically including: a point light source 9, a collimating beam expander 10, a detected hydrogen transmission pipeline 11, a first Grating 12 , first Fourier lens 13 , second grating 14 , spectrum processor 15 , second Fourier lens 16 , signal receiving screen 17 , micro-control unit 18 , alarm device 19 .

When the hydrogen leakage optical detection system is running, the light emitted by the point light source 9 is divided into two paths after passing through the collimating beam expander 10 and the first grating 12, wherein one path passes through the tested hydrogen pipeline 11 and the first Fourier lens. 13. After the spectrum processor 15 and the second Fourier lens 16, the high signal-to-noise ratio imaging features are collected by the signal receiving screen 17; the other way passes through the tested hydrogen pipeline 11 and the second grating 14, and then the signal receiving screen 17 Diffraction features are collected.

When there is hydrogen leakage in the pipeline, the refractive index of the gas around the tested hydrogen pipeline 11 will change, affecting the optical path of the light emitted by the point light source, thereby changing the collected high signal-to-noise ratio imaging and diffraction characteristics. The collected signals are sent to the Micro Control Unit (MCU) for processing. By comparing with the high signal-to-noise ratio imaging and diffraction characteristics under normal conditions, it can be judged whether the hydrogen pipeline is leaking. Once hydrogen leakage is detected, the micro-control unit controls the alarm device (Alarm) 19 to issue an alarm message, informing the staff to take corresponding measures in time to ensure the safety and stability of the photoelectric hydrogen production process. The system uses two optical paths for leak detection and sampling of hydrogen pipelines, which improves the reliability of the detection system and greatly reduces the false alarm rate.

Next, the detection method of the above-mentioned system will be described with reference to FIG. 3. During detection, the gas source to be tested is located in the overlapping area of the two optical paths to ensure that the optical signal passing through the surrounding gas can be collected. The gas leak detection method includes:

S1. Move the detection system to the vicinity of the gas source to be detected;

S2, point the light source and collect high signal-to-noise ratio imaging and diffraction features, and transmit the collected information to the signal processing module;

S3. The signal processing module processes the received information and determines whether gas leakage occurs.

The method simultaneously uses two optical paths for leak detection and sampling of the hydrogen pipeline, which improves the reliability of the detection system and greatly reduces the false alarm rate. Under this detection method, if the gas leaks, the refractive index of the gas in the detection area will be changed, thereby affecting the high signal-to-noise ratio imaging and diffraction pattern collected in the step S2. Features are analyzed and determined in real time to obtain gas leakage information. The gas leak information includes: whether the gas leaks and the concentration of the leaked gas.

Further, if it is determined that gas leakage occurs, the determination result is output to the alarm device, and the alarm device immediately receives and responds to the abnormal information and generates an alarm signal.

The above-mentioned embodiments are only intended to illustrate the technical concept and characteristics of the present application, and the purpose is to enable those who are familiar with the technology to understand the content of the present application and implement them accordingly, and cannot limit the protection scope of the present application. All equivalent transformations or modifications made in accordance with the spirit and spirit of this application shall be covered within the protection scope of this application.

Claims (7)

1. a gas leak detection system, is characterized in that, comprises: Signal acquisition optical system, signal processing module and alarm; The signal acquisition optical system includes: a light source, a spectroscopic element, a 4f Fourier system, a spectrum processor and a dispersion element; The spectrum processor is set on the spectrum plane in the 4f Fourier system, and the light emitted by the light source is divided into two paths after passing through the light splitting element, After passing through the 4f Fourier system all the way, the imaging information containing the gas with high signal-to-noise ratio in the detection area is transmitted to the signal processing module; The other way transmits the diffraction information containing the gas light in the detection area to the signal processing module after passing through the dispersive element; The signal processing module analyzes and determines the collected high signal-to-noise ratio imaging and diffraction characteristics in real time, and transmits the determination result to the connected alarm device. 2 . The gas leak detection system according to claim 1 , wherein the spectroscopic element comprises: a transflective element and a spectroscopic prism. 3 . 3 . The gas leak detection system according to claim 1 , wherein the dispersive element comprises: a grating and a prism. 4 . 4 . The gas leak detection system according to claim 1 , wherein the light source is a point light source, the light intensity emitted by the light source is lower than the ignition energy of the gas to be detected, and the light emitted by the point light source is collimated. 5 . After the beam is expanded, it is incident on the beam splitting element. 5 . The gas leak detection system according to claim 4 , wherein the gas to be detected comprises: hydrogen gas and natural gas. 6 . 6. The gas leak detection system of claim 1, wherein: The 4f Fourier system includes: The first Fourier lens and the second Fourier lens, The image-side focus of the first Fourier lens is set at the object-side focus of the second Fourier lens, and the first Fourier lens and the second Fourier lens are coaxially placed. 7. The gas leak detection system according to claim 1, wherein: The signal processing module analyzes the collected high signal-to-noise ratio imaging and diffraction characteristics in real time and determines whether there is gas leakage information, and transmits the result to the connected alarm. The gas leakage information includes: whether the gas leaks and/or leaks Gas is thick.

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