It has a long history using a throttle device to measure the flow volume of fluid in pipe the method has formed normalization at home and abroad the principle is to make the flow bunch form the particial shrink at the place where the throttle part is located so as to produce a static pressure difference then measure and calculate the flow volume at the moment when the fluid is flowing through the throttle device by the static pressure measured this method is based on the law of conservation of energy and the equation of flow continuity 用节流装置测量管道中流体流量已历史悠久，在国内、国际上都已标准化，其原理是使流束在节流件处形成局部收缩，产生静压力差，通过测量静压力差来衡量流体流过节流装置时的流量大小，这种测量方法是以能量守恒定律和流动连续性方程为基础的。
