1. What is the GPM Flow Rate Calculator?

Definition: This calculator estimates the flow rate in gallons per minute (GPM) for a hydraulic pump based on its RPM and displacement volume.

Purpose: It helps engineers and technicians determine pump performance and system requirements in hydraulic applications.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Flow rate (gallons per minute)
• \( RPM \) — Rotational speed (revolutions per minute)
• \( D_p \) — Pump displacement (cubic inches per revolution)
• \( 231 \) — Conversion factor (cubic inches per gallon)

Explanation: The formula multiplies pump speed by displacement to get cubic inches per minute, then converts to gallons per minute.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate calculation ensures proper system design, pump selection, and performance evaluation in hydraulic systems.

4. Using the Calculator

Tips: Enter the pump RPM and displacement (in³/rev). Both values must be > 0. The result shows theoretical flow rate at 100% volumetric efficiency.

5. Frequently Asked Questions (FAQ)

Q1: Why is 231 used in the formula?
A: 231 cubic inches equals 1 US gallon, converting the volume measurement from cubic inches to gallons.

Q2: What affects actual flow rate vs theoretical?
A: Actual flow may be less due to factors like pump efficiency, system pressure, and fluid viscosity.

Q3: How do I find my pump's displacement?
A: Check manufacturer specifications or calculate from pump geometry (bore × stroke × number of chambers).

Q4: Does this work for all pump types?
A: This applies to positive displacement pumps (gear, piston, vane). Centrifugal pumps follow different principles.

Q5: How does pressure affect the calculation?
A: Pressure doesn't directly affect theoretical flow rate, but higher pressure may reduce actual flow due to internal leakage.