一种时分双频励磁电磁流量计设计*

摘要

A time-division dual-frequency excitation scheme is proposed as an improvement to the low frequency square wave excitation technique in tradition electromagnetic flowmeters for it's disadvantages including slow response,weak immunity to low frequency noise and inadequacy for instable flow measurement. The proposed scheme keeps the advantage of stable zero point which is the main advantage of the traditional design,immunity to low frequency noise is enhanced,and the response to fast change of fluid velocity is improved. A prototype flowmeter is made based on the proposed design,experiment results showed that the prototype flowmeter can measure water flow in a wide velocity range with satisfactory accuracy.%针对采用低频方波励磁的传统型电磁流量计响应速度慢、抗低频干扰能力较差、不适应流速剧烈变化情况下流量测量的缺点，提出一种结合高频方波励磁与低频方波励磁特点的时分双频励磁方案。新方案保持了传统方案零点稳定的优点，提高了抗低频干扰的能力，改善了对被测流体流动状态快速变化的适应性。根据所提方案研制了原理样机，样机测试和实验结果表明，采用本文方案实现的电磁流量计在较宽的流速测量范围内能保持测量结果准确性基本不受流动状态影响，可实现高精度的流量测量。