What this tool does

Screen manufacturer curve points against one required flow and head. The tool sorts points and linearly interpolates only within the entered range.

When to use it

Use it after flow and TDH are known and while comparing current manufacturer curves for equivalent conditions.

Inputs and supported units

Each labelled field explains the quantity it expects. Unit-system changes convert existing numeric entries once and keep calculations on a single SI internal basis. Supported shared units include L/min and GPM, metres and feet, kPa and psi, millimetres and inches, kW and hp, and °C and °F as relevant.

Calculation or decision method

H(Q) = H₁ + (H₂ − H₁)(Q − Q₁)/(Q₂ − Q₁)

Interpolation uses the two entered points bracketing duty flow. The tool does not extrapolate, fit a quadratic curve or invent a manufacturer performance map.

How to interpret the result

Read the primary result with the supporting breakdown and warning. A plausible number is not evidence that every input, operating case or design constraint has been included.

Worked example

For points 0,60; 100,50; 200,30, a duty flow of 120 gives 46 head units by linear interpolation. Compare that with the required head in the same units.

Assumptions

All points share one flow/head unit system and represent the exact pump configuration being compared.

Limitations

No system curve, affinity-law adjustment, efficiency island, power limit, NPSH curve or operating-region boundary is generated.

Safety and review boundary. Verify the result on the current certified or published manufacturer curve, including impeller, speed and allowable operating region.

Sources