A rotary vane pump uses a slotted rotor and sliding vanes inside a surrounding cam ring. Chamber volume increases on the inlet side and decreases on the outlet side. This calculator converts entered displacement, speed, volumetric efficiency and pressure difference into idealized flow, fluid-power and torque references.
Vane Pump Interactive Calculator
Enter displacement per revolution, shaft speed, an assumed volumetric efficiency and pressure difference. Results are idealized flow, power and torque calculations—not a pump rating, input-power prediction, thermal analysis or selection approval.
Equation Used
- Displacement is entered directly in cubic centimetres per revolution.
- Speed, volumetric efficiency and pressure difference are steady independent inputs.
- Entered volumetric efficiency is applied as a scalar multiplier to ideal displacement flow.
- Theoretical torque excludes friction, hydrodynamic and mechanical losses.
- The topology animation is schematic and does not infer cam-ring eccentricity from entered displacement.
- Fluid properties, leakage law, inlet conditions, cavitation, temperature, mechanical efficiency, drive power, pulsation, bearing loads, stress, wear, rated limits and safety are omitted.
Documented Rotary-Vane Topology
Harry F. Vickers' U.S. Patent 1,989,900 documents a vane-type pump with a rotor, radially movable vanes and a surrounding pumping chamber. U.S. Patent 2,511,573 describes pressure-balanced vane construction for hydraulic power transmission. These sources support the slotted rotor, sliding-vane, inlet and outlet topology illustrated here.
The drawing is schematic. Entered displacement does not uniquely determine rotor diameter, cam-ring shape, eccentricity, vane count or port geometry.
What This Calculator Represents
The tool multiplies entered displacement by speed for ideal swept flow, applies the entered volumetric-efficiency scalar, converts pressure-flow product to fluid power and computes theoretical pressure-volume torque.
Idealized Pump Calculations
efficiency-adjusted flow Qadj = eta_v Qideal
fluid power Ph = Delta p Qadj / 600
theoretical torque Tth = Delta p D / (20 pi)
The unit constants apply to D in cm³/rev, n in rpm, pressure in bar, flow in L/min, power in kW and torque in N·m.
Worked Arithmetic Example
At 20 cm³/rev and 1,500 rpm, ideal displacement flow is 30.0 L/min. With an entered 90% volumetric efficiency, adjusted flow is 27.0 L/min. At 100 bar pressure difference, fluid power is 4.50 kW and theoretical pressure-volume torque is 31.8 N·m.
Model Boundary
- Calculated: ideal displacement flow, scalar efficiency-adjusted flow, fluid power and theoretical torque.
- Illustrated: generic rotor, radial slots, sliding vanes, cam ring and inlet/outlet regions.
- Not calculated: shaft input power, mechanical or overall efficiency, actual leakage curve, temperature rise, inlet loss, cavitation, noise, ripple, bearing load, vane contact stress, life, rated envelope or safety.
Manufacturer literature shows that real flow and power are evaluated from model-specific performance data and leakage curves.
Frequently Asked Questions
Is efficiency-adjusted flow a guaranteed actual flow?
No; it is ideal flow multiplied by the entered efficiency.
Is fluid power the required shaft power?
No; mechanical losses are absent.
Is theoretical torque actual drive torque?
No.
Does displacement set the drawing's eccentricity?
No.
Does the calculator check cavitation or inlet conditions?
No.
Can it select or rate a pump?
No.
References
- U.S. Patent 1,989,900, Vane type pump: rotor, movable vanes and hydraulic pumping construction.
- U.S. Patent 2,511,573, Vane pump construction: pressure-balanced rotary vane pump for hydraulic power transmission.
- Parker Hannifin, Vane Pumps General Catalog: displacement, theoretical flow, leakage, available flow and input-power selection workflow.
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