1. What is a Pump GPM Calculator?

Definition: This calculator estimates the flow rate (GPM) of a pump based on its horsepower, efficiency, and head.

Purpose: It helps engineers and technicians determine the expected flow rate of a pump under specific operating conditions.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Flow rate (gallons per minute, GPM)
• \( HP \) — Pump horsepower (HP)
• \( \eta \) — Pump efficiency (dimensionless, 0-1)
• \( H \) — Total dynamic head (feet)

Explanation: The formula converts mechanical power to hydraulic power, accounting for pump efficiency and the work needed to overcome head.

3. Importance of Pump GPM Calculation

Details: Accurate flow rate estimation ensures proper pump selection, system design, and energy efficiency in fluid transport systems.

4. Using the Calculator

Tips: Enter the pump horsepower (HP), efficiency (default 0.85), and total head in feet. Efficiency must be between 0 and 1 (typically 0.7-0.9 for most pumps).

5. Frequently Asked Questions (FAQ)

Q1: What is the constant 3960 in the formula?
A: This is the conversion factor that relates horsepower to foot-pounds per minute (1 HP = 3960 ft-lb/min).

Q2: What's a typical pump efficiency value?
A: Centrifugal pumps typically range from 70-90% efficiency (0.7-0.9), while positive displacement pumps can be higher.

Q3: What exactly is "head" in this calculation?
A: Head represents the total dynamic head - the height difference plus friction losses in the piping system, measured in feet of fluid.

Q4: Can I use this for different fluids?
A: The formula uses water as reference (8.34 lb/gal). For other fluids, adjust the 8.34 factor to match the fluid's specific weight.

Q5: How does GPM relate to system requirements?
A: The calculated GPM should meet or exceed your system's flow requirements while considering the pump's performance curve.