Pressure before and after the control valve
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What is the role of the pressure before and after the control valve? Is the throat diameter of the control valve calculated in this way?
The pressure difference before and after the control valve (the difference between the pressures on the upstream and downstream sides, that is, the pressure difference before and after the valve under normal operating conditions as well as the pressure difference when the valve is closed) is an important parameter for selecting and calculating control valves (such as the flow capacity Cv or Kv values). Flow characteristics, flow ratios, and other parameters are all determined using this value. Based on the calculation results, select a control valve that meets the process control requirements. The importance of this value cannot be ignored.
One aspect is choosing the type of valve, such as a single-seat valve or a sleeve valve. Generally, single-seat valves are used when the pressure difference is not high; sleeve valves are chosen for higher pressure differences, and for even higher differences, sleeve valves with multiple pressure-reduction stages may be necessary. Secondly, the flow capacity and control performance are calculated based on the pressure difference, thereby determining the appropriate diameter. Another factor is selecting the actuator for the control valve based on the pressure difference and sealing level.
The severity of operating conditions can also be determined based on pressure difference and temperature, to assist in valve design