There are different types of freezing techniques in the food industry. The two main types of freezing methods are: cryogenic freezing and mechanical freezing.
CRYOGENIC FREEZING EQUIPMENT
With cryogenic freezing, the food ingredients are sprayed or immersed directly in liquid nitrogen or carbon dioxide. This causes the product to be frozen almost immediately, while the freezing sustenance is evaporated in the atmosphere. In general, the up-front capital costs are low with cryogenic freezing equipment when you compare it to mechanical freezing equipment.
However relative large amounts of freezing sustenance are being used, which results in high ongoing costs for the producers. Besides this, there is the issue that cryogenic vapours are colourless and odourless, so extra attention is necessary to make sure that proper ventilation is in check to protect personnel from oxygen displacement.
– Cryogenic freezing is mostly used for individual quick frozen (IQF) products, such as frozen peas, individual chicken wings, and other bulk packaged foodstuffs where separate pieces are necessary.
– Cryogenic freezing is sometimes a preferred as a low-cost method with getting new products quickly to the market.
MECHANICAL FREEZING EQUIPMENT
Common mechanical freezing systems use electrical power to generate chilled air. The cold air will be uninterruptedly blowing over the food product and therefore removing heat. These systems are relatively more expensive to operate compared to cryogenic freezing.
With mechanical freezing, common refrigerants like ammonia or carbon dioxide are used. Mostly this process engages in a standard mechanical refrigeration cycle. The process of mechanical freezing systems typically involves higher capital costs than cryogenic systems, due to the fact that they require additional supporting systems. However, when you look at the long-term, they are usually more efficient and cost-effective in their use.
Especially for the high-volume production of raw and finished of raw and finished products mechanical freezing is typically applied.
FREEZER TYPES AND THEIR APPLICATIONS
There are many different types of freezers. Some are specifically designed for certain product types, as the application may differ in process conditions and quantities. A superior product quality can be ensured through choosing the right freezing equipment with the most efficient freezing process.
Some types of universally used freezers are listed below, together with a brief description of standard purposes and functions:
PROCESS FREEZERS: Process freezers are usually integrated into the production line, right before the end-of-line packaging part of the production line.
IQF – IQF freezers can come with both mechanical and cryogenic systems, but most of the time they are cryogenic. Read more about IQF freezers here.
SPIRAL – Spiral freezers can be both mechanical or cryogenic. This type of freezer moves the foods onto a conveyor that spirals inside an insulated enclosure for a certain amount of time to the point of freezing. Read more about spiral freezers here.
TUNNEL – Tunnel freezers work in a similar way as spiral freezers, but they move the product in a linear pattern. Read more about tunnel freezers here.
PLATE – A plate freezer is a special hollow plate that has liquid refrigerant flowing through it. Products are placed between two plates and then evenly cooled to freezing temperatures. These freezers are ideal for flat foods or brick-shaped packaged foods, for example frozen meals.
BLAST FREEZERS: Blast freezers are mechanical freezing type systems. They are commonly used to mass freeze products in bulk on pallets. Blast cells are separated from manufacturing, and not part of the production line like process freezers; the food is airtight in a blast cell and stays there for several days as cold air is continuously distributed throughout the room.
As an organization that is looking for proper freezing equipment, it would be a helpful advice to work together with a dealer specialized in freezing equipment to ensure the system is qualified for the specific product. More often than not, food plant owners work together with the specialist provider for a custom-designed freezing system. When you invest in new freezing equipment, it is important that your excess freezing equipment is removed in a safely manner. Click here to know more about dismounting food machinery.