1、 The measurement principle of the throttling device is that when the fluid filled in the pipeline flows through the throttling device inside the pipeline, the flow beam will form a local contraction at the throttling point, thereby increasing the flow velocity and reducing the static pressure, resulting in a static pressure difference (or differential pressure) before and after the throttling element. The higher the flow velocity of the fluid, the greater the difference generated before and after the throttling element, so measuring the differential pressure can be used to measure the fluid flow through the throttling element