1. What is a Hydraulic Flow Rate Calculator?

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

Purpose: It helps hydraulic system designers and technicians determine the flow rate needed for proper system operation.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

Explanation: The pump displacement multiplied by RPM gives cubic inches per minute, which is converted to GPM.

3. Importance of Flow Rate Calculation

Details: Proper flow rate estimation ensures adequate system performance, prevents pump cavitation, and helps select proper components.

4. Using the Calculator

Tips: Enter the pump RPM and displacement (in³/rev). Both values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is 231 the conversion factor?
A: There are 231 cubic inches in one US gallon, which converts the volume measurement.

Q2: What's a typical displacement for hydraulic pumps?
A: Common displacements range from 0.1 in³/rev for small pumps to 10+ in³/rev for large industrial pumps.

Q3: Does this work for all pump types?
A: This formula works best for positive displacement pumps (gear, piston, vane). Centrifugal pumps require different calculations.

Q4: How does efficiency affect the calculation?
A: For more accurate results, multiply the result by the pump's volumetric efficiency (typically 85-95%).

Q5: What if I need L/min instead of GPM?
A: Multiply the GPM result by 3.785 to convert to liters per minute.