The advantage of the blast freezer is its versatility. It can cope with a variety of irregularly shaped products and whenever there is a wide range of shapes and sizes to be frozen, the blast freezer is the best choice.
Designing air blast freezers
The use of air to transfer heat from the product being frozen to the refrigeration system is probably the most common method used in commercial refrigeration. The natural convection of the air alone would not give a good heat transfer rate, therefore, forced convection by means of fans has to be introduced. To enable the product to be frozen in a reasonable time the air flow rate should be fairly high. Also, in order to obtain uniform freezing rates throughout the freezer, the air flow requires to be consistent over each fish or package.
Selecting which freezing method to use is usually determined by quality specifications, economics and availability. Each food product has its own unique characteristics which determine their appropriate freezing temperature and freezing rate. Typical products frozen in air blast freezers include but are not limited to:
- Meat - carcasses, cartons, large individually wrapped cuts, cured or processed, hamburger patties
- Poultry - whole bird or pieces, processed or breaded products
- Fish – whole or eviscerated, fillets or small diced pieces, processed or breaded products, shellfish, prawns and shrimp
- Fruits – small size (whole), large size (sliced), purée or pulp
- Vegetables – small and medium size, leafy
- Other – Cheese and butter, dough, bread and baked products, pre-cooked ready meals