Milk Cooling Tanks

A milk cooling tank, also known as a bulk milk cooler, is a critical piece of equipment on a dairy farm. Its main purpose is to rapidly cool raw milk to a temperature of about ²4∘C (³39∘F) and hold it there until it is collected, which prevents bacterial growth and maintains the milk’s quality.

Here are the key features of a modern milk cooling tank:

1. Construction and Insulation

• High-Quality Stainless Steel: Both the inner and outer shells of the tank are typically constructed from high-quality food-grade stainless steel (often SUS304) for durability, hygiene, and corrosion resistance. The inner tank is polished to ensure easy and thorough cleaning.
• Insulation: The space between the inner and outer tank is filled with a high-density insulating material, usually polyurethane foam. This insulation is highly effective and ensures that the milk temperature will not rise significantly (e.g., only 1∘C over 24 hours) even in the event of a power failure.
• Adjustable Legs and Tilt: The tank stands on adjustable legs (4, 6, or 8 depending on size) to ensure it is level. The inner tank often has a slight built-in tilt towards the outlet to ensure complete drainage.

2. Cooling System

• Refrigeration Unit: This includes a compressor, condenser, and evaporator (often a dimple plate on the inner tank wall). The system is designed for rapid direct cooling of the milk, typically from around 38∘C (cow temperature) to 4∘C quickly to minimize bacterial growth.
• Temperature Control: An advanced electrical control box manages the cooling process using a thermostat. It automatically monitors and regulates the temperature to ensure it remains stable and does not allow the milk to freeze.

3. Agitation and Mixing

• Agitator/Mixer: Every tank is equipped with at least one automatic agitator (stirrer) that mixes the milk intermittently. This is crucial for:
  • Rapid Cooling: Ensuring all the milk is quickly and evenly exposed to the cold inner walls.
  • Homogeneity: Preventing the cream from rising and ensuring the temperature is consistent throughout the entire volume.

4. Accessibility and Hygiene

• Manhole/Lid: A large, watertight manhole (access point) on top of the tank allows for thorough inspection and manual cleaning if necessary.
• Inlets and Outlets:
  • Inlets: Small inlets on top are used to pump milk into the tank; one usually has an air vent.
  • Outlet: A threaded outlet, usually at the bottom, is used for draining the milk and is typically fitted with a valve or faucet.
• Automatic Cleaning System (CIP): Most modern tanks include a Clean-In-Place (CIP) system. This involves a pump and spray lance that cleans the inner tank automatically using hot/cold water and acid/alkaline cleaning fluids after the milk is emptied, ensuring a hygienic environment for the next batch.

5. Monitoring and Control

• Control Box: This central unit allows the user to turn the system on/off, manage the thermostat, start the cleaning routine, and initiate extra stirring.
• Thermometer/Temperature Display: A clear display allows for immediate inspection of the milk temperature.
• Monitoring and Alarm System: Newer or larger tanks include sophisticated systems that:
  • Guard the milk temperature.
  • Check the functioning of the cooling unit and agitator.
  • Activate an alarm in case of any malfunction or deviation from the required temperature range.
  • Keep a record (data logging) of temperature and performance over time for quality control.

Features of our milk cooling tanks

Saset milk cooling tanks are made of high quality stainless steel that ensures they cannot rust. Milk has some chemical components that can react with metal and cause it to rust. However the stainless steel we use is food grade meaning it cannot be affected by milk.

Our milk cooling tanks are highly polished both inside and outside to ensure they don’t easily attract dirt. On the inside we also polish them well to remove any small pockets where milk particles might hide when cleaning and make milk future milk stored to get spoilt.

The milk cooling tanks come with a cooling mechanism that ensures milk stays cold at required temperatures. The cooling mechanism ensures that the desired low temperatures are achieved. The tank also has an insulation that prevents warm temperatures from outside do not affect the cold temperatures inside the tank.