Research And Implementation Of Ultrasonic Detection System For Small Leakage Signals

The detection of small leakage signals is important to prevent leakage accidents and ensure safe production.At present,ultrasonic leak detection method is widely used because of its non-interventional detection and detection sensitivity.For the detection of pipeline leakage signal and partial discharge ultrasonic signal,this paper designed and realized the ultrasonic detection system of small leakage signals.The main work includes as follows:1.This paper designed and realized the hardware circuit and software module of the small leakage signal ultrasonic detection system.Hardware circuit mainly consists of the conditioning module of small leakage signal,the heterodyne frequency reduction and power amplifier module,ADAS3022 analog-to-digital conversion module,LCD display touch control module and detection system interface module,etc.Software modules include Linux embedded ARM end,the local oscillator signal control AD9833 heterodyne ADAS3022 modulus conversion,control and LCD display,and other functions,Dsp limited long unit impulse response filter and base 2 time-domain sampling fast Fourier transform of digital signal processing algorithm,and the validation for computing power of DSP.2.A test platform of pipeline gas leakage and a partial discharge test platform were established to realize the effective detection of small leakage signals.Firstly,the performance of the ultrasonic testing system of small leakage signals is tested through simulated pipeline leakage signals and partial discharge signals.Then,the characteristics of the leakage signals and the physical factors affecting the leakage signals are studied.The experimental results shown that:i)The conditioning module of small leakage signal can realize the amplification of the 100 microvolt level signal without distortion;ii)The proposed system detected leakage of contact type and non-contact type and displayed the leakage signal in real time;iii)The hole diameter of leakage and pressure affected the amplitude and frequency characteristics of leakage source,and the amplitude and frequency of the leakage signal detected by sensors were affected by the factors such as distance,medium.