Engineering
Pump Power Calculator
Calculate the shaft power required for centrifugal pumps in dairy and food processing applications. Input flow rate, head, density, and efficiency.
Formula
(flowRate * head * density * 9.81) / (3600000 * (efficiency / 100))
flowRate
Flow Rate (m³/hr)
head
Total Head (m)
density
Fluid Density (kg/m³)
efficiency
Pump Efficiency (%)
Worked Example
1
Given:
density = 1030
efficiency = 75
flowRate = 50
head = 30
2
Apply the formula:
(flowRate * head * density * 9.81) / (3600000 * (efficiency / 100))
3
Result:5.65 kW
Centrifugal Pump Power Calculation
Selecting the right pump motor size is critical. Undersized motors will fail. Oversized motors waste energy.
Power (kW) = [Flow Rate (m³/hr) × Head (m) × Density (kg/m³) × g] ÷ [3,600,000 × Efficiency]
Where g = 9.81 m/s²
Understanding Total Head
Total head = Static head + Friction head + Velocity head
- Static head: Height difference between suction and discharge points
- Friction head: Pressure loss in pipes, fittings, and valves
- Velocity head: Usually small, often ignored
Motor Sizing Tips
Always add a 15–20% safety factor on top of calculated power when selecting a motor.
| Calculated Power | Recommended Motor |
|---|---|
| < 3.7 kW | 5 HP (3.7 kW) |
| 3.7–5.5 kW | 7.5 HP (5.5 kW) |
| 5.5–7.5 kW | 10 HP (7.5 kW) |
| 7.5–11 kW | 15 HP (11 kW) |
Common Dairy Pump Applications
| Application | Typical Flow | Typical Head |
|---|---|---|
| Milk transfer | 10–100 m³/hr | 10–40 m |
| CIP pump | 20–50 m³/hr | 20–50 m |
| Homogenizer feed | 5–30 m³/hr | 15–30 m |
| Cream separator feed | 10–50 m³/hr | 10–25 m |