Design And Implementation Of Portable Ultrasonic Gas Leakage Detector

With the production and development of modern industry,the transportation and storage of gas is particularly important,such as gas storage tanks,gas transportation pipelines,etc.,which are widely used in factories.However,due to their own reasons and external factors,these equipment will inevitably leak,resulting in energy waste and even safety accidents.So how to detect and locate leakage quickly and efficiently is an urgent problem to be solved.Theoretical analysis shows that ultrasonic leak detection is affected by signal detection factors such as detection direction angle and detection distance.Because the size of the leakage aperture and the change of the pressure in the container will lead to the change of the center frequency of the ultrasonic signal at the leakage,a wide frequency band is generally used to cover these frequencies when designing the detection system,but the wide frequency band will lead to the decline of the detection signal-to-noise ratio,so that the weak ultrasonic signal is submerged by the environmental noise.Based on the principle of ultrasonic testing,a portable gas leakage detector is designed with STM32 processor as the core.The system mainly designs a sound concentrator and a hardware detection system.The sound concentrator is mainly used for signal enhancement.Through simulation analysis by COMSOL software,the shape,length,taper and other factors of the sound concentrator are analyzed,and a more suitable sound concentrator is determined.In the aspect of hardware system,it mainly completes the selection of sensors,the design of signal conditioning circuit,the design of frequency reduction circuit and the design of microprocessor.The software mainly completes the signal analog-to-digital conversion,fast Fourier transform and signal spectrum display.BThe work flow of the portable ultrasonic gas leak detector designed in this paper is that when there is a gas leak signal,the signal is enhanced by the sound concentrator,then received by the ultrasonic sensor,conditioned by the signal conditioning circuit,the conditioned signal is collected by STM32,and then the characteristic quantity of the signal is analyzed to judge whether there is a leak and the specific location of the leak.Through the establishment of the pipeline gas leakage experiment,the time domain analysis and frequency domain analysis of the leakage hole under the conditions of different aperture and different distance are carried out to observe the characteristics of the ultrasonic signal of gas leakage.The experimental results show that the handheld device developed in this subject can judge whether there is leakage by scanning the surface of the container to be tested,can indicate the location of the leakage source,and can detect the leakage of the container in real time.