Formulas for Centrifugal Pump

Formulas for Centrifugal Pumps

I know what maximum PSI and maximum GPM I need. What size pump do I need?

Centrifugal Pump Formula:

Minimum Horsepower Required = ((Max GPM) X (Max PSI) / 1710) / (Efficiency in Percentage) X (Specific Gravity of Material)

How do I calculate PSI (Pressure in Pounds Per Square Inch) or TDH (Total Dynamic Head)?

Assuming you have one measurement for your pump but not the other:

PSI = TDH / 2.31

TDH = PSI X 2.31

How do I calculate Brake Horsepower Required for a centrifugal pump?

Brake Horsepower Required = GPM Required X (Total Dynamic Head) / 3940 / Efficiency

General Equations

(1) Barrel = 42 gallons

Gallons Per Minute = Barrels Per Day X .0292

GPM = BPD * .0292

HorsePower = Torque in Inch Pounds X (Revolutions Per Minute) / 63,025

HP = ((Torque in Inch Pounds) * RPM) / 63,025

1 US Liquid Gallon = 231 Cubic Inches

1 US Liquid Gallon = 231 Inches^3

1 US Liquid Gallon = 0.13368 Cubic Feet

1 US Liquid Gallon = 0.13368 Feet^3

1 US Liquid Gallon = 3.78541 Liters

1 Liter = 0.26417 US Liquid Gallons

1 Cubic Foot = 7.84 US Liquid Gallons

1 Foot^3 = 7.84 US Liquid Gallons

1 Cubic Foot = 28.31685 Liters

1 Foot^3 = 28.31685 Liters

Cubic Feed Per Day = Cubic Feet Per Minute X 1440

Feet^3 Per Day = (Feet^3 Per Minute) * 1440

Cubic Feet Per Minute = Cubic Feet Per Day Divided by 1440 Minutes Per Day

Feet^3 Per Minute = (Feet^3 Per Day) / 1440 Minutes Per Day

Chart of Relative Density / Specific Gravity

for Common Liquids

Specific Gravity is used when sizing a centrifugal pump. Liquids with a specific gravity greater than 1.0 are heavier than water and conversely, liquids with a specific gravity lower than 1.0 are lighter weight than water and will generally float on water.

Material | Degrees Celsius | Degrees Fahrenheit | Specific Gravity |

Alcohol, ethyl (ethanol) | 25 | 77 | 0.787 |

Alcohol, methyl (methanol) | 25 | 77 | 0.791 |

Alcohol, propyl | 25 | 77 | 0.802 |

Butane,...