Refrigeration & Equipment Engineering

Unit 5 - Freezers

5.2.1.Air blast freezer
The big advantage of the air blast freezer is its versatility. it can cope with a variety of the irregularly shape products and sizes to be frozen, the blast freezer is the best choice.In order to obtain uniform freezing rates throughout the freezer, the air flow requires to be substantially the same over each fish or package. A good design fan air speed of 5m/see been founded to be a good compromise between slow freezing rates and high fan cost and this air speed recommended for most air blast freezing. There are many different designs of air blast freezer both for batch and continuous operation. Details are given of a number of types of air blast freezer in common use. With comment on their suitability for various products and methods of processing and also on their limitations.

In continuous air blast freezer the product move through the freezer usually entering at one end and all leaving at the other.Product may be move through the freezer on trucks or trolleys or they may be loaded on a continuously moving belt or conveyor .