Selection of control valves

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Selection process of control valves 1 Determination of flow rate. The existing production capacity, equipment load, and condition of the medium determine the calculated flow rates Qmax and Qmin. Determination of the pressure difference before and after the 2 valves. Based on the selected valve flow characteristic and system properties, S (the resistance coefficient) is determined, after which the calculated pressure difference is established. 3 Calculate Cv. Based on the medium being used, select the appropriate calculation formulas and charts to determine Cmax and Cmin. 4 Choose Cv. Based on Cmax, select the primary C value from the selected series of product standards that is closest to Cmax. 5 Verification of the control valve opening degree. Generally, the opening degree at the maximum calculated flow rate should be greater than or equal to 90%, while it should be less than or equal to 10% at the minimum calculated flow rate. 6 Verification of the actual adjustable ratio of the control valve. Generally, it is required that the actual adjustable ratio be less than or equal to 10. 7 Determination of valve seat diameter and nominal diameter. After verification is satisfactory, it is determined according to C.