Fresh milk must be cooled quickly, otherwise there will be a deterioration of the milk quality due to increased microbial growth. It is a regulation that the milk from one milking must be cooled down in a relatively short time, according to EN 13732 Class C II in 3 hours from 35°C to 4°C at 25°C ambient temperature. The maximum storage temperature of milk that is not collected every day is 6 °C.
For large quantities of milk that have to be cooled ETSCHEID provides a heat exchange station.
This cooling device immediately cools fresh milk to a storage temperature of 4 - 6 ° C.
The subsequent storage tank does not require any or only a small cooling system in order to keep the milk at the correct storage temperature.
Plate heat exchanger
With this type of cooling, milk is pumped through a plate heat exchanger. Cooling water flows through this plate heat exchanger in counter-flow method and thus cools the milk to the desired storage temperature. The required amount of cooling water (cooling energy) must be provided by an external cooling system, for example an ETSCHEID Aquacooly.
To ensure a uniform milk flow through the plate heat exchanger and thus to achieve a constant milk storage temperature, fresh milk is collected in a balance tank first. Level electrodes signal when the balance tank is filled with milk. When the required level has been reached, a milk pump is started, which pumps the milk with a constant, variable flow through the plate heat exchanger. The cooled milk has the optimal storage temperature at the output of the plate heat exchanger and is pumped into the storage tank. If the amount of milk in the balance tank falls below a certain minimum amount, the milk pump will be stopped and fresh milk will be collected in the balance tank.
The balance tank, the heat exchanger and the milk line to the storage tank are cleaned by the integrated automatic cleaning Lavatronic AWE / XL in a circulation process.
To increase the efficiency of the heat exchanger station, an additional plate
heat exchanger for precooling the milk by tap water is recommended.
A sufficient amount of cold water (10 ° C to 15 ° C) has to be available. This water cools the freshly milked milk down to about 16°C to 20°C. Because of that a refrigeration unit of a smaller power class can be used for the subsequent cooling of the milk to an appropriate storage temperature, which in turn lowers the operating and acquisition costs significantly. The heated water from the plate pre-cooler is usually fed to the watering place.
Components of the heat exchanger:
- Plate heat exchanger (stainless steel), balance tank (stainless steel) and milk pump mounted on a stainless steel base plate.
- Additional plate heat exchanger for pre-cooling milk with water can be integrated.
- Integrated Cleaning System AWE / XL with heating up to 2 x 8.4 kW.
- Milk pump with functions for the delivery of the milk to the storage tank and for cleaning the balance tank, the plate heat exchanger and the milk line to the storage tank.