Reciprocating and Metering Pumps — online
Capacity, slip and brake power for simplex to nonuplex pumps, flow pulsation from the crank motion, acceleration head and NPSH with or without a suction dampener, and metering stroke settings.
Yellow cells are inputs; orange cells are choices; blue cells choose the unit. Select or hover over an input to see its help in the box below the toolbar. The sheet is the same as the Excel tool (USD 29) — the Guide, method and references are in the Excel file.
What this reciprocating and metering pumps calculator does
Positive displacement pumps cavitate for a different reason. This tool finds it. Capacity, slip and brake power for simplex to nonuplex pumps, flow pulsation from the crank motion, acceleration head and NPSH with or without a suction dampener, and metering stroke settings.
- Every common type. Simplex to nonuplex, single or double acting, power or direct-acting steam pumps, metering pumps with stroke setting.
- Capacity and power. Displacement, slip, hydraulic and brake power by Ludwig's equations.
- Flow pulsation. Instantaneous flow over one crank turn and the variation above and below the mean — matches Ludwig's published patterns.
- Acceleration head and NPSH. ha = L·v·n·C/(K·g) with HI/GPSA constants, friction at peak flow, NPSH margin and the suction pipe size that fixes it.
- Dampener effect. Acceleration head with and without a suction pulsation dampener.
- Findings. Insufficient NPSH, pulsation, speed and relief-valve reminders in plain words.
What you enter
- Pump type
- Drive
- Suction dampener
- Liquid class for the acceleration head (K)
- Liquid data
- Liquid
- Pumping temperature
- Concentration (% by mass)
- Watson characterisation factor K
- Kinematic viscosity at 40 °C
- Kinematic viscosity at 100 °C
- Density at the pumping temperature
- Viscosity at the pumping temperature
- Specific heat
What you get
- Displacement per stroke (one cylinder, head end)
- Theoretical displacement
- Actual capacity (displacement × volumetric efficiency)
- Differential pressure
- Hydraulic power (actual capacity × ΔP)
- Brake (shaft) power
- Flow variation above the mean (calculated)
- Flow variation below the mean (calculated)
- Peak instantaneous flow
- Acceleration constant C (used)
- Mean suction line velocity
- Acceleration head ha = L·v·n·C / (K·g)
- Suction friction at peak flow
- Suction pipe size that gives the minimum margin
How it was checked
Reproduces all seven Ludwig Fig. 3-68 flow patterns and the HI/GPSA acceleration constants within 4 %; six cases match an independent Python model exactly.
Related
- Calculation guide — the equations behind this tool, with a worked example.
- Reciprocating and Metering Pumps Excel tool — USD 29, keep the workbook and its Guide.
- All 40 online tools
Questions
Is the reciprocating and metering pumps calculator free?
You can enter and check all your data free. The full results, findings and printable sheet are unlocked with a 3-run pack (USD 9), a monthly subscription to all 40 online tools (USD 15) or a yearly one (USD 99).
Are the results the same as the Excel tool?
Yes. The online tool runs the formulas of the Reciprocating and Metering Pumps Excel workbook, checked cell by cell against the Excel file.
Which units can I use?
SI, US customary and British units — choose the unit next to each input.