CWR Resources provides high quality used freezing systems machines for industrial use.
Which types of freezing technologies are used in the food processing industry right now?
Many food processors find it difficult to choose the right freezing equipment at the start, as there are so many choices that are often confusing.
The freezing time is one of the most important parameters in the freezing process. The freezing time represents the time needed to reach a specific temperature below zero in a product’s thermal center, and its importance lies in determining the quality of the final product and its operating costs.
The International Institute of Refrigeration defined the following factors, which include the shape and size of the product. The temperatures of the product, the temperature of the refrigerating medium, the surface heat transfer coefficient of the product, the change in total heat content in the system, and the thermal conductivity of the product. Therefore, to achieve optimal freezing results, it is important to choose the right equipment for specific products.
There are 9 different types of different freezers:
Air Blast Freezer or Cold Storage Freezer
The air freezer or cold storage is probably the oldest kind of freezer, which is using still or forced air as a medium; the product is kept static in a freezing storage room. Of course, this is the simplest method with the lowest investment costs. The largest or unprocessed products are best frozen using this method; however, it is one of the slower methods of freezing.
Cartoon Freezer/ Box Freezer
Cartoon freezers or box freezers are complicated mechanical freezers based on a relatively simple freezing concept. Products already packaged and placed in boxes are sorted, transported, and stored by an automated device, placing them on shelves with cold blasts of air.
Spiral Belt Freezer
This spiral belt freezer provides a good solution for gentle products as it reduces product damage at transferring points by bending the belt around a central supporting structure. This technology also offers the advantage of large production areas on a small footprint, allowing continuous production with limited manpower.
Fluidized Bed Freezer or IQF Freezer (Tunnel Freezer)
The fluidized freezer, or IQF freezer, is sometimes called tunnel freezer in South and North America and is based on a belt or perforated bed on which the product is fluidized by strong vertical airflow passing from beneath the bed/belt. This is the most complex freezing technology since the product cannot be statically frozen and multiple variables will affect the freezing result, such as shape, aerodynamics, ripeness, firmness, or water content of the product.
Immersion Freezer or Brine Freezer
In an immersion freezer, the product is fully immersed in a tank of cooled freezing media which may be a chemical or a salt or sugar solution. Immersion freezing is the fastest freezing method, which is commonly used as a pre-treatment of large products to create a frozen layer before the product is subjected to longer freezing times, to reduce dehydration.
Plate Freezer or Block Freezer
The most common method of contact freezing is by pressing the product between two hollow plates with a refrigerant flowing inside. The freezers are only suitable for block-frozen products of normal shape or small products, such as seafood. The technology is used as a first step during the processing of seafood as a fast freezing solution for preservation.
Contact Belt Freezer
Contact belt freezers consist of the product laid on a single band or a double band and are often used to freeze thin products, such as egg yolks, soup, fruit pulp, or other very soft products.
Impingement Freezer / Flat Product Freezer
This freezing method is best suited for flat products such as hamburgers as high-speed air is blown on the product during impingement freezing. However, this freezing method cannot be used for too big or too small products.
This technology involves exposing a product directly to liquefied gases, usually nitrogen or carbon dioxide, in an atmosphere of approximately -76°F. There are two main types of the cryogenic freezer – the ones that use immersion or dipping of the product into the medium and those that spray the medium onto the product. Both types of freezers transport the product continuously on a belt to the other end of the freezer.
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