Flow elements

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Orifice plates
ORIFICE GAS FLOW EQUATION
Qv = 218.527*Cd*Ev*Y1*(d2 )*[Tb/Pb]*[(Pf1*Zb*hw)/(Gr*Zf1*Tf)]0.5 (3-6)
​Where Cd = Orifice plate coefficient of discharge
d = Orifice plate bore diameter calculated at flowing temperature (Tf) - in.
Gr = Real gas relative density (specify gravity)
hw = Orifice differential pressure in inches of water at 60 degF
Ev = Velocity of approach factor
Pb = Base pressure - psia
Pf1 = Flowing pressure (upstream tap - psia
Qv = Standard volume flow rate - SCF/hr.
Tb = Base temperature - degR
Tf = Flowing temperature - degR
Y2 = Expansion factor (downstream tap)
Zb = Compressibility at base conditions (Pb,Tb)
​Zf1 = Compressibility (upstream flowing conditions - Pf1, Tf)

Venturi

Wedge

Integral flow element

Control valves

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Globe Valves 

Butterfly valves

Ball valves

Relief valves

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Spring actuated

Pilot actuated