Dairy equipment
What this domain tests
This domain tests selection, sanitary design and basic duty calculations for dairy equipment such as tanks, pumps, plate heat exchangers, separators, homogenizers and pasteurizers.
Core rules
- Product-contact surfaces should be food-grade stainless steel, commonly AISI 304 or 316, with smooth welds and no crevices.
- Sanitary design avoids dead ends, sharp corners and pockets; equipment should drain completely and be easy to clean.
- Centrifugal pumps suit low-viscosity milk; positive-displacement pumps suit viscous products and gentle handling.
- Plate heat exchangers give close temperature control and heat recovery but need correct gasket and plate integrity.
- Separators and homogenizers are sized by flow rate, pressure and product type; instruments need calibration.
Worked example
A plate heat exchanger heats 1000 kg/h of milk from 10°C to 72°C. Take specific heat cp = 3.9 kJ/kg·K. Heat duty Q = m cp ΔT = 1000 × 3.9 × (72−10) = 241,800 kJ/h. Divide by 3600 s/h to get about 67.2 kW. This is the process heat load before allowing for heat recovery and losses.
Traps
Do not use a centrifugal pump for very viscous or shear-sensitive product without checking. A higher-grade steel does not compensate for bad welds or dead legs. Ignoring heat recovery can oversize the heater. Equipment capacity must match peak intake, not average, or milk will wait and deteriorate.