01 · Inputs
Nameplate numbers first.
Valve Cv, head loss, NPSH, volumes. No hidden estimates.
FlowCalc · flowcalculators.com
Flow, Valve, Pump & Tank Calculators — 32 Screening Tools with Visible Math
Control-valve sizing, piping head loss, pump duty and NPSH, flow metering, tank strapping, and control-loop checks — every output labeled, every formula substituted, every margin shown. Free to run; sign in only to save.
- 32 screening calculators
- 6 tool families
- 8 worked guides
- Machine-checked test suite
Method
Inputs in. Math shown.
02 · Math
Every output labeled.
Cv, head loss, power, NPSH, volumes. Each with its formula.
03 · Verify
Field-check before relying.
Datasheet, field readings, applicable codes. Margins shown.
Calculators
Pick the job.
Control Valves
Liquid Cv Flow Calculator
Liquid Cv to flow at given dP and specific gravity. Kv = 0.865 x Cv.
Open calculatorPiping & Head Loss
Pipe Velocity
Mean velocity from flow and inner diameter: v = Q/A.
Open calculatorPiping & Head Loss
Friction Loss (Darcy-Weisbach)
Darcy-Weisbach screening: laminar f=64/Re, turbulent Blasius f=0.316/Re^0.25.
Open calculatorPumps
Pump Head and Power
Hydraulic power Ph = rho*Q*H/366972. Shaft = Ph/eff. Motor with 15% margin.
Open calculatorFlow Metering
Orifice dP-Flow (Screening)
Orifice screening Q = C sqrt(dP/rho). Calibrate C from one known point; full ISO 5167 for custody.
Open calculatorTanks & Level
Vertical Tank Volume
Vertical tank V = pi/4 D^2 h.
Open calculatorGuides
Worked examples.
Article
Why Valve Opening % Is Not Flow % (And What to Enter Instead)
Opening percent positions the stem. Flow percent follows the installed Cv(h) curve and the live pressure drop.
Article
Control Valve Sizing in 10 Minutes: Cv, dP, SG Workflow
Four steps from design flow to a selectable trim: Cv, metric conversion, margin, recheck.
Private Workspace
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