Control Valves
Actuator Sizing Margin
Actuator margin = (rated/required - 1) x 100%. Require >= 25%.
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Flow calculators
Control-valve sizing, piping head loss, pump duty and NPSH, flow metering, tank strapping, and control-loop checks — every output labeled, every formula visible.
Control Valves
Gas Valve Flow (Screening)
Gas valve screening with choked-flow flag at P2/P1 <= 0.5. Full sizing per IEC 60534.
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Pump Head and Power
Hydraulic power Ph = rho*Q*H/366972. Shaft = Ph/eff. Motor with 15% margin.
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Friction Loss (Darcy-Weisbach)
Darcy-Weisbach screening: laminar f=64/Re, turbulent Blasius f=0.316/Re^0.25.
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Reynolds Number
Reynolds number Re = rho v D / mu. Regime: 0 laminar, 1 transitional, 2 turbulent.
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Pipe Diameter from Velocity
Required inner diameter from flow and target velocity, round up to standard DN.
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Pipe Velocity
Mean velocity from flow and inner diameter: v = Q/A.
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Valve Pressure Drop
Valve pressure drop from flow and Cv: dP = SG x (Q/Cv)^2.
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Cv Kv Converter
Cv to Kv and Kv to Cv. Kv = 0.865 x Cv.
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Valve Opening Curve Estimator
Opening-to-flow ONLY with manufacturer curve data. Never assume 50% open = 50% flow.
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Required Cv from Flow
Required Cv from target flow, dP and SG, with 20% margin recommendation.
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Liquid Cv Flow Calculator
Liquid Cv to flow at given dP and specific gravity. Kv = 0.865 x Cv.
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