Pump Selection Guide for Dairy Plants
A complete pump selection guide for dairy and food processing plants — centrifugal vs PD pumps, sizing, cavitation, NPSH, and installation best practices.
Types of Pumps in Dairy Plants
1. Centrifugal Pumps
Most common for liquid milk and water transfer.
Pros: Simple, low maintenance, cheap, variable flow
Cons: Not self-priming, poor with viscous products, shear-sensitive
Applications: Milk transfer, CIP, chilled water, cooling water
2. Positive Displacement Pumps
a) Rotary Lobe Pump
Pros: Gentle, handles viscous products, self-priming, sanitary design
Cons: More expensive, needs timing gears, higher maintenance
Applications: Cream, yogurt, ice cream mix, chocolate, butter transfer
b) Peristaltic Pump
Pros: Very gentle, sterile, easy to clean, handles solids
Cons: High tube wear cost, limited capacity
Applications: Dosing of cultures, enzymes, vitamins, flavors
c) Gear Pump
Pros: High pressure capability, accurate metering
Cons: Not hygienic design typically, shear-sensitive
Applications: Ghee, vegetable fat, non-food fluids
Pump Sizing — Step by Step
Step 1: Determine Required Flow Rate
From process design: litres per hour based on plant capacity + 20% safety factor
Step 2: Calculate Total Dynamic Head (TDH)
TDH = Static Head + Friction Losses + Pressure Head
- Static head: Elevation difference (m)
- Friction: Use Darcy-Weisbach equation or pipe friction charts
- Pressure head: Vessel pressures converted to metres
Step 3: Select Pump from Curve
Plot Q and H on pump performance curve. Select pump where duty point falls at BEP.
Step 4: Verify NPSH
NPSHa ≥ NPSHr + 0.5 m (safety margin)
NPSHa = (Atmospheric pressure − Vapor pressure) / ρg + Suction head − Friction in suction pipe
Common Pump Power Formula
Hydraulic Power (kW) = ρ × g × Q × H / (3,600 × 1,000)
Where: ρ = liquid density (kg/m³), g = 9.81, Q = flow in L/h, H = head in meters
Shaft Power = Hydraulic Power / Pump Efficiency
→ Use our Pump Power Calculator for quick calculations.
CIP vs Product Pumps
| Parameter | Product Pump | CIP Pump |
|---|---|---|
| Design | 3A/EHEDG hygienic | Industrial (can be hygienic) |
| Material | 316L SS, PTFE seals | 304 or 316L SS |
| Flow | Typically lower | Higher (for turbulence) |
| RPM | Variable (VFD for control) | Constant (high velocity) |
| Head | 10–25 m | 25–40 m |
Installation Best Practices
- Minimize suction lift — install pump below tank where possible
- Keep suction line short and large — improves NPSHa
- Install strainer on suction — protect pump impeller/rotor
- Isolating valves on both sides — for maintenance
- Pressure gauge on discharge — monitor pump performance
- Flexible couplings — reduce pipe stress and vibration transmission