The Design Of Echo Automatic Level Instrument For Coal Bed Methane Well

Fluid level of CBM wells is an important parameter in the mining process. It is important to adjust exploitation system and improve gas production. Therefore, the design of echo automatic fluid level of CBM wells can reduce manual errors in traditional measurement and improve the level of automation about fluid level measurement.On the basis of analyzing the feasibility of using low-frequency sound waves to measure the fluid level, design the hardware of the measuring instrument and software implementation. For CBM well, analyze the characteristics of sound generator and receiver. Design analog signal conditioning modules, including signal amplification, low-pass filtering circuit and so on. System uses MSP430F149 as the core processor. Design interface circuits, power modules, and data display module. Compare the processing method of echo signals in time domain and frequency domain, choose frequency-domain analysis to focuse on analyzing the frequency domain characteristics of the echo signal. Use digital filter to wipe out interference signals. Research the principle of discrete Fourier transform algorithm. Spectrum analysis is carried on coupling wave by improved fast Fourier transform algorithm. The fundamental frequency is extracted and converted to velocity. According to the characteristics of reflected wave, identify the reflection position of the liquid level and calculate depth of dynamic liquid level.According to the measurement, program the software to realize the echo signal data acquisition, fast Fourier transform algorithm, level identification and results display. Compare the single chip processing results and the simulation data by MATLAB software to test the reliability and accuracy of the system.