Hp To Gpm Calculator

GPM Formula:

\[ GPM = \frac{HP \times 3960 \times Efficiency}{Head \times SG} \]

Horsepower (HP):

Efficiency:

decimal (0-1)

Head:

Specific Gravity (SG):

dimensionless

Gallons Per Minute (GPM):

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1. What is the HP to GPM Formula?

The HP to GPM formula calculates the flow rate in gallons per minute (GPM) based on horsepower (HP), pump efficiency, head, and specific gravity. This calculation is essential for pump system design and analysis in various engineering applications.

2. How Does the Calculator Work?

The calculator uses the GPM formula:

\[ GPM = \frac{HP \times 3960 \times Efficiency}{Head \times SG} \]

Where:

\( HP \) — Horsepower input to the pump
\( Efficiency \) — Pump efficiency (decimal value between 0-1)
\( Head \) — Total dynamic head in feet
\( SG \) — Specific gravity of the fluid (dimensionless)
\( 3960 \) — Conversion constant

Explanation: This formula converts mechanical power (HP) to flow rate (GPM) while accounting for pump efficiency, the height the fluid must be lifted (head), and the density of the fluid (specific gravity).

3. Importance of GPM Calculation

Details: Accurate GPM calculation is crucial for proper pump selection, system design, energy efficiency analysis, and ensuring adequate fluid flow for various industrial, agricultural, and residential applications.

4. Using the Calculator

Tips: Enter horsepower as a positive number, efficiency as a decimal between 0 and 1, head in feet, and specific gravity (1.0 for water). All values must be greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the significance of the 3960 constant?
A: The constant 3960 comes from the conversion of horsepower (550 ft-lb/sec) to gallons per minute, considering that one gallon of water weighs 8.34 pounds.

Q2: How does specific gravity affect the calculation?
A: Higher specific gravity (denser fluids) requires more power to achieve the same flow rate, or results in lower flow rates for the same power input.

Q3: What is typical pump efficiency range?
A: Pump efficiency typically ranges from 0.5 to 0.85 (50-85%), depending on pump type, size, and operating conditions.

Q4: Can this formula be used for all pump types?
A: This formula is generally applicable to centrifugal pumps. Positive displacement pumps may require different calculations due to their different operating characteristics.

Q5: How does head affect GPM calculation?
A: Higher head requirements result in lower flow rates for the same horsepower input, as more energy is needed to overcome the increased elevation or pressure difference.