Pressure drop control valve

Rather than assuming a pressure drop across the control as 25%, 33%, or 40% of the other friction losses in the system, a logical approach [9] is summarized here. The control valve pressure drop has nothing to do with the valve size, but is determined by the pressure balance (See Equation 2-59 [9]). 

Ps = 168 psi, at pump discharge, using assumed control valve pressure drop of 35 psi... 

Factors to consider in ev aluating the control valve pressure drop are ... 

Example 2-4 Using Figure 2-26, Determine Control Valve Pressure Drop and System Start Pressure (See Example 2-3)... 

Use this as estimated control valve pressure drop for the system design. 

Pressure drop, chart, 102, 103, 111 Computer aided drafting, 17 Condensate, flashing flow, 135-142, 147 Charts, 142, 143 Control valve pressure drop, 90 Calculations, 90-96 Cost estimates, plant, 45-49 Accounting, 48... 

Control valve pressure drop, allow normal (xl.22) maximum Heat exchanger, allow normal (xl.22) maximum Orifice, allow normal (xl.22) maximum... 

Control Valve Pressure Drop Beat Inherent Characteristic... 

Please first note that these calculated answers have been rounded off conservatively to the higher values. The reason is that greater acuracy is not justified. The control valve pressure drop selected should be within a tolerance of 10% of the total system pressure loss the control valve governs. 

Control valve pressure drop, allow normal... 

The computer program PROG52 calculates the control valve capacity coefficient (C ) or the maximum flow rate that will pass through the valve. Table 5-9 shows the input data and results of the control valve calculations for liquid, gas, and steam conditions. For the liquid service, at a flow rate of 400 gpm and the control valve pressure drop of 25 psi, the control valve capacity coefficient (CJ is 80. The gas service with a flow rate of 1200 fP/h, and control valve pressure drop of 400 psi gives the control valve capacity coefficient (C ) of 0.059. For the steam condition of capacity coefficient (C, ) = 75, and the control valve pressure drop of 10 psi, the maximum steam flow rate through the valve is 5511.4 Ib/hr. 

CAPACITY COEFFICIENT FOR FULLY OPEN VALVE CONTROL VALVE PRESSURE DROP, psi. 

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