1. What is Pump Sizing Calculation?

The pump sizing calculation determines the required horsepower for a pump based on flow rate, head, specific gravity, and pump efficiency. It's essential for selecting the right pump for a given application.

2. How Does the Calculator Work?

The calculator uses the pump power equation:

Where:

• \( HP \) — Horsepower (output)
• \( Q \) — Flow rate in gallons per minute (GPM)
• \( H \) — Total head in feet (ft)
• \( SG \) — Specific gravity (dimensionless, 1 for water)
• \( \eta \) — Pump efficiency (decimal from 0 to 1)

Explanation: The equation calculates the power required to move a fluid at a given flow rate against a specific head, accounting for fluid density and pump efficiency.

3. Importance of Pump Sizing

Details: Proper pump sizing ensures energy efficiency, prevents overloading motors, extends equipment life, and ensures the system meets performance requirements.

4. Using the Calculator

Tips: Enter flow rate in GPM, head in feet, specific gravity (1 for water), and pump efficiency as a decimal (e.g., 0.8 for 80%). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical pump efficiency value?
A: Centrifugal pumps typically range from 40-85% efficiency (0.4-0.85). Always check manufacturer specifications for exact values.

Q2: How do I determine total head?
A: Total head includes static head, friction losses, and pressure differences. It's the sum of all resistance the pump must overcome.

Q3: What's the 3960 constant in the formula?
A: This is a conversion factor that accounts for units (1 HP = 550 ft-lb/sec) and water density (8.33 lb/gal).

Q4: Should I add a safety factor?
A: Yes, it's common practice to add 10-20% to the calculated HP to account for system variations and future needs.

Q5: How does viscosity affect pump sizing?
A: High viscosity fluids require more power and may need special pump designs. The calculator assumes water-like viscosity.