What are the types of differential pressure flowmeters?
The differential pressure flowmeter consists of a primary device and a secondary device. The primary device is called a flow measuring element, which is installed in the pipeline of the measured fluid to generate a pressure difference proportional to the flow (flow rate) for the secondary device to display the flow. The secondary device is called display instrument. It receives the differential pressure signal generated by the measuring element and converts it into the corresponding flow for display. The primary device of the differential pressure flowmeter is usually a throttling device or a dynamic pressure measuring device (pitot tube, uniform velocity tube, etc.). The secondary device is a variety of mechanical, electronic and combined differential pressure gauges with flow display instruments. The differential pressure sensitive elements of the differential pressure gauge are mostly elastic elements. Since the differential pressure and the flow rate are in the square root relationship, the flow display instruments are equipped with square root devices to linearize the flow scale. Most of the instruments are also equipped with a flow integration device to display the accumulated flow for economical calculation. This method of using differential pressure to measure flow has a long history and is relatively mature. It is generally used in more important occasions in countries all over the world, accounting for about 70% of various flow measurement methods. This meter is used for flow measurement of main steam, feed water, condensate, etc. in power plants.
Mechanics principle: Instruments belonging to this kind of principle include differential pressure type and rotor type using Bernoulli's theorem; impulse type and movable tube type using momentum theorem; direct mass type using Newton's second law; Target type; turbine type using the theorem of angular momentum; vortex type and vortex street type using the principle of fluid oscillation;
