Size pump head fast for cold liquid transfer safely. Compare suction and discharge piping losses. Use consistent units, validate inputs, and export summaries quickly.
| Scenario | Inlet / Outlet Pressure | Flow | Elevations | Suction (D, L, ΣK) | Discharge (D, L, ΣK) |
|---|---|---|---|---|---|
| Liquid transfer skid | 200 kPa → 600 kPa | 25 m³/h | 0 m → 12 m | 100 mm, 8 m, 4 | 80 mm, 50 m, 8 |
| Short run, higher fittings | 150 kPa → 520 kPa | 18 m³/h | 1 m → 9 m | 90 mm, 6 m, 8 | 65 mm, 20 m, 14 |
| Long discharge header | 260 kPa → 820 kPa | 32 m³/h | 0 m → 15 m | 125 mm, 10 m, 5 | 90 mm, 120 m, 10 |
Tip: Use measured density and viscosity at operating temperature for the most reliable head estimate.
The calculator estimates required pump head using the extended energy equation:
H = (P₂ − P₁)/(ρg) + (z₂ − z₁) + (v₂² − v₁²)/(2g) + hf + hm
hf = f (L/D) (v²/2g) •
Minor loss: hm = ΣK (v²/2g)
f = 64/Re.
Engineering note: For cryogenic service, check cavitation margin separately (NPSH) and confirm material limits, flashing risk, and insulation assumptions.
Cryogenic transfer lines operate with narrow temperature margins, rapid density shifts, and sensitive equipment limits. A practical head estimate helps field teams select pumps that reach target delivery pressure while maintaining stable flow. In construction projects, temporary runs, elevation changes, and many fittings can inflate losses beyond nameplate assumptions. Using a consistent method reduces commissioning delays, minimizes rework, and supports safer start-up planning.
Total head is influenced by differential pressure, static lift, velocity changes, and piping losses. Use measured density and viscosity at operating temperature whenever possible, because small property shifts can move Reynolds number and friction factor noticeably. Enter suction and discharge lengths, diameters, and a realistic total minor-loss coefficient (ΣK) for valves, elbows, strainers, reducers, and entry or exit effects.
Friction losses scale with L/D and with velocity squared, so smaller diameters can raise head quickly at higher flow. Minor losses also scale with velocity squared and become dominant in compact skids packed with fittings. If the suction line includes parallel branches or manifolded sections, use the velocity override fields to reflect the actual path velocity.
Compare the calculated total head with the pump curve at the desired flow to confirm operating point and margin. If head is high, consider increasing discharge diameter, reducing fittings, shortening runs, or adjusting set pressure. For cryogenic service, always review cavitation margin separately and confirm insulation and flashing assumptions so suction conditions remain stable during transient loading.
Example inputs: inlet pressure 200 kPa, outlet pressure 600 kPa, flow 25 m³/h, elevations 0 m to 12 m, suction 100 mm by 8 m with ΣK 4, discharge 80 mm by 50 m with ΣK 8, density 800 kg/m³, viscosity 0.2 cP, roughness 0.045 mm. Run the calculation and export the summary for field documentation.
Total pump head is the energy per unit weight the pump must add to meet pressure, elevation, and piping-loss requirements at the specified flow.
Density affects pressure head conversion, while viscosity influences Reynolds number and friction factor. Both can vary strongly with temperature and change losses and required head.
Sum K values for fittings and valves along the line, including entrance and exit effects. If uncertain, use conservative values and refine after layout is finalized.
Use overrides when flow splits into parallel paths, passes through manifolds, or when the effective velocity differs from the simple single-pipe calculation.
No. This estimates required head for the system. NPSH checks suction pressure margin against vapor pressure to reduce cavitation risk and must be verified separately.
The calculator uses the laminar relationship f = 64/Re. Verify assumptions, because laminar flow can occur at very low viscosity or flow, affecting performance and stability.
Reduce velocity by increasing diameter, shorten pipe runs, remove unnecessary fittings, select low-loss valves, and optimize route elevation. Recalculate to confirm improvements.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.