When designing a throttling device for calculations, how should the differential pressure value be selected?

When designing and calculating throttling devices, the selection of the differential pressure value should take into account the following factors: a) A higher differential pressure value allows for a shorter minimum length of straight pipe. b) When the differential pressure is high, the β value decreases, and a lower minimum Reynolds number is recommended for use. In this way, the actual minimum Reynolds number can be much higher than the recommended value, thereby stabilizing the flow coefficient and improving the measurement accuracy. c) For differential pressure transmitters, generally, those with a larger differential pressure are more stable than those with a smaller one. d) When the differential pressure is high, the pressure loss in the throttling element is also large, which is not conducive to energy savings. On large-diameter low-pressure gas pipelines, it also significantly limits the flow capacity, thereby restricting the production capacity of the equipment.

1. Meet the requirement for the maximum pressure loss specified by the process. 2. Meet the β range requirements for use in throttling devices. 3. Under the conditions specified in 1 and 2, the differential pressure is generally chosen from 6, 10, 16, 25, 40, 60, and 100 KPa (it seems that these values are more suitable due to the design of differential pressure gauges); the orifice plate is usually set at a value between 0.5 and 0.6.

The simplest approach is to set it as follows: take the maximum allowable pressure loss specified in the process, multiply it by 2–3, and then round the result to 10, 16, 25, or 40 KPa. . . Calculate B using the differential pressure limit of the orifice plate. If the rated flow rate is 1.5 times the operating flow rate, then B is around 0.5. @jiaguoyun