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一、前言应用孔板或喷咀等节流装置的差压式流量计,如果被测气体在工作状态下的温度、压力、密度(组成)与设计节流装置时的基准值不同,则被测气体的密度将发生变化,从而产生误差。通常虽然在分别测量出差压、压力、温度和密度(组成)等参数后,这种误差可进行计算校正,或从相应的修正表中求得正确的流量值,但在流量控制时,这种计算是来不及的。对于流量积算值,一般采用某一段时间内的温度、压力、密度的平均值来校正,但逐一进行这一计算是相当麻烦的,而且往往会发生误差。因此,自动地校正温度、压力、密度(组成)的变化所引起的误差,並连续指示、记录、积算或控制正确流量的自动校正流量计是迫切需要的。
I. INTRODUCTION Differential pressure flow meter with orifice or nozzle throttling device. If the measured gas temperature, pressure, density (composition) in the working state is different from the baseline value when the throttling device is designed, Gas density will change, resulting in errors. Usually, after measuring parameters such as differential pressure, pressure, temperature and density (composition) respectively, this error can be calculated and corrected, or the correct flow value can be obtained from the corresponding correction table. However, in flow control, Calculation is too late. For the flow totalizer, the average temperature, pressure, density over a certain period of time is generally used to correct, but one by one this calculation is quite troublesome, and often errors occur. Therefore, it is imperative that an automatic calibration flow meter that automatically corrects for errors caused by changes in temperature, pressure, density (composition), and continuously indicates, records, integrates, or controls the correct flow rate.