How is the pressure drop of a control valve determined?
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Is pressure drop the same as loss of pressure? How was it determined?
For control valves, the pressure drop refers to the pressure difference before and after the control valve; take a look at http://bbs.hcbbs.com/viewthread.php?tid=251629 as well
If it relates to the process parameters for pipeline valve selection, it should be the allowable pressure difference provided by the process engineering team based on the losses in the equipment pipelines. Given the pressure loss of the valve, it can be calculated using the following formula. (Discussion) Formulas for calculating valve pressure loss Formula 1: △P = (Q/Kv)² △P = pressure loss, in bars; Q = flow rate, in m³/h; Kv = (nominal pressure difference of 1 bar), in m³/h Formula 2: △P = 0.0102 × (Q/Kv)² △P = pressure loss, in millimeters of water column; Q = flow rate, in l/h; Kv = (nominal pressure difference of 1 bar), in m³/h Formula 3: △P = 0.01 × (Q/Kv0.01)² △P = pressure loss, in bars; Q = flow rate, in l/h; Kv0.01 = (nominal pressure difference of 0.01 bar), in l/h Formula 4: △P = 102 × (Q/Kv0.01)² △P = pressure loss, in millimeters of water column; Q = flow rate, in l/h; Kv0.01 = (nominal pressure difference of 0.01 bar), in l/h Formula 5: Kv = 0.01 × Kv0.01 Kv = (nominal pressure difference of 1 bar), in m³/h; Kv0.01 = (nominal pressure difference of 0.01 bar), in l/h Last edited by chmyh on 2009-2-4 11:12]
It is determined based on the pressure required by the pipeline downstream of the valve or the process flow; you can reduce it by as much as you want...
Each manufacturer’s control valve has its own calculation software to determine its pressure drop, flow rate, and opening degree. Of course, the standards also include corresponding calculation formulas, but the calculation errors are relatively large.