Flowers processing vacuum cooler
Vacuum cooler & Hydro-vacuum cooler brief introduce
Vacuum cooling involves reducing the pressure inside an airtight chamber. The water inside the vegetables turns into steam, absorbing thermal energy. Vacuum cooling works best for products that easily lose water, such as lettuce and baby leaf crops.
The hydroelectric suction cooling devices add a misting system to avoid the loss of moisture from the product. At the same time, water cooling can help cool down more quickly and make compact vegetables suitable for the vacuum cooling process.
Vacuum cooling is a fast and energy-efficient method of maintaining freshness.
What is vacuum cooling? (In detail)
Vacuum cooling removes the heat from the vegetables by boiling part of the water contained.
The products are loaded into a strong sealed vacuum chamber and the air is pumped out. This reduces the normal air pressure to a virtual vacuum (<1KPa). Under these conditions, the water boils at <7 ° C.
Since water in vegetables changes from liquid to gas, it absorbs thermal energy from the product, cooling it. This vapor is removed by dragging it behind the refrigeration coils, which condense it back into liquid water.
For vacuum cooling to cool vegetables quickly, they must be able to easily lose moisture. For this reason vacuum cooling is very well suited to leafy products, such as lettuce, Asian vegetables and fresh flowers. Products such as broccoli, celery and corn can also be cooled effectively with this method. Vacuum cooling is not suitable for products with wax or low surface speed / volume, eg carrots, potatoes, tomatoes or courgettes.
For every 5 ° C of temperature reduction, about 1% of the product weight must be transformed into water vapor. However, modern hydro-vacuum coolers address this problem by spraying water on the product during the vacuum process. This can reduce moisture loss to negligible levels.