差压式涡街质量流量计信号处理系统的研制

Development of Signal Processing System for Differential Pressure Type Vortex Mass Flowmeter

差压式涡街质量流量计是一种新型的质量流量测量装置,通过测量旋涡发生体上下游管壁处的差压,同时获取涡街频率信号和压力损失信号。为了将差压中这两路信号分离并准确测量其值,研制了采用程控放大、自适应滤波技术及FFT算法的信号处理系统。实验结果表明,该信号处理系统能够准确地从差压式涡街质量流量计输出信号中测得管内流体的质量流量值,同时改善了装置的抗干扰能力和通用性,提高了涡街频率测量的准确度,并且具有结构简单、成本低、适用性广等优点。

Differential pressure type vortex mass flowmeter is a new kind of device for mass flowrate measurement. Differential pressure upstream and downstream of the bluff body is measured on the duct wall in the meter, from which vortex frequency and pressure difference should be obtained. In order to separate these two signals and measure their values respectively, a signal processing system based on programmable gain amplification, adaptive filtering and fast Fourier transform algorithm is developed. Experiment results show that the signal processing system can properly measure mass flowrate from the differential pressure of vortex mass flowmeter. It increases the anti-noise ability and commonality of the meter, and improves the accuracy of vortex frequency measurement. The system has many other advantages such as simple configuration, low cost, and wide applicability.