1. What is the Pump RPM to Flow Rate Relationship?

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

Purpose: It helps hydraulic engineers and technicians understand and predict pump performance characteristics.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

Explanation: The formula calculates how much fluid volume is displaced per minute based on the pump's rotational speed and displacement per revolution.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate prediction is essential for system design, performance analysis, and troubleshooting hydraulic systems.

4. Using the Calculator

Tips: Enter the pump RPM and displacement per revolution (in³/rev). Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

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

Q2: Does this work for all pump types?
A: This applies specifically to positive displacement pumps where flow is directly proportional to RPM.

Q3: How accurate is this calculation?
A: It provides theoretical flow rate. Actual flow may be less due to efficiency losses, slippage, and system backpressure.

Q4: What's a typical displacement value?
A: Displacement varies by pump size and design, ranging from 0.1 in³/rev for small pumps to over 10 in³/rev for large industrial pumps.

Q5: Can I calculate RPM from flow rate?
A: Yes, rearrange the formula: \( RPM = \frac{Q \times 231}{D_p} \).