Pipeline Leak Signal Enhancement Module Design Based On Dual Sensor

Pipeline has particular advantages in transporting articles in mobile phase, such as liquid, gaseous, slurry phase, and the like, and is especially widely applied in remote transportation of petroleum and pipeline natural gas (PNG). Pipeline leakage would result in not only waste of valuable energy but also great economic loss. Moreover, pipeline leakage would cause environment pollution in leakage areas. Rapid and accurate collection of leakage signal is a key to achieve pipeline leakage detection. However, it brings difficulties to accurate and high-precision leakage orientation that leakage signal is not obvious and signal-to-noise ratio is not high due to interference of environment noise, variation of working conditions and inherent error of detection devices, and other factors.The present thesis provides a method for strengthening leakage signal. The method is implemented based on dual sensor. That is, two sensors are mounted at relatively short distance in initial and final stations respectively, interference signal transmitted from sites located upstream of the initial station and downstream of the final station is eliminated by delay subtracting dynamic press singles obtained by adjacent two sensors, thereby signal output of transducer after delay subtraction approximates zero. After delay subtracting leakage signals transmitted from pipeline section between the first and initial stations, the output signal of transducer is doubled in amplitude, then leakage signal is strengthened. The specific process is as follows:controlling high-speed AD for sampling by employing CPLD, implementing delay subtraction of sampling signals according to control signal emitted by AVR single microcomputer, outputting the subtraction result through DA and transmitting the output data by RS-485 bus line to the upper computer for further analysis and processing.After simulation experiment and analog signal testing, the leakage signal strengthening module based on dual sensor presented by the present thesis can achieve expected target, and the module operates steadily.