# Control Valve Sizing

The control valve sizing calculator given here can be used to estimate the flow coefficient or orifice coefficient of the valve. This flow coefficient for a valve depends on type of valve, pressure & flow conditions and desired inherent characteristic of the valve.

This is something you may need to know for your online degree program in engineering. Here is some helpful information.

 FLOW INPUTS Pin(Inlet pressure) barg Pout(outlet pressure) barg T(Fluid temperature) 0C WL(liq mass flowrate) kg/hr WG(vapour mass flowrate) kg/hr Overmargin for flow % LIQUID INPUTS ρ (liq. density) kg/m3 PC(liq. Critical pressure) bara PV(Vapour pressure at inlet T) bara VAPOUR INPUTS M(Vapour molecular weight) gm/gmole Z (compressibility factor) CP/CV(gamma ratio at inlet T) VALVE SPECIFIC INPUTS (Refer to the table given below.) Cf (Critical flow factor) XT (Pressure drop ratio factor) FP (Correction factor for fittings) FR (Correction factor for non-turbulent flow) RESULTS Cvliq (liquid phase coefficient) Cvvap (vapor phase coefficient) Cv (Overall flow coefficient)

The table given below, provides valve specific factors for a variety of valves.

 Valve type Trim Type Cf XT Globe, single port 3 V-port plug 0.9 0.7 4 V-port plug 0.9 0.7 6 V-port plug 0.9 0.7 Contoured plug 0.9 0.72 60 diameter hole drilled cage 0.9 0.68 120 equal diameter hole drilled cage 0.9 0.68 Characterized cage, 4 port 0.9 0.75 Globe, double port Ported Plug 0.9 0.75 Contoured plug 0.85 0.7 Globe, angle Contoured plug 0.9 0.72 Characterized cage, 4 port 0.9 0.65 Venturi 0.85 0.6 Globe, small flow trim V-notch 0.98 0.84 Flat seat 0.85 0.7 Tapered needle 0.95 0.84 Rotary Eccentric spherical plug 0.85 0.6 Eccentric conical plug 0.77 0.54 Butterfly (centered shaft) Swing-through (70 °) 0.62 0.35 Swing-through (60 °) 0.7 0.42 Fluted vane (70 °) 0.67 0.38 High performance butterfly (eccentric shaft) Offset seat (70 °) 0.67 0.35 Ball Full bore (70 °) 0.74 0.42 Segmented ball 0.6 0.3

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