What Is a Tunnel Freezer?

A tunnel freezer is a cryogenic freezer that uses liquid nitrogen (at -196 degCelsius) or carbon dioxide to rapidly cool food products that enter hot or at room temperature at one end and leave cold or frozen at the other. These conveyor-based systems can be used as stand-alone freezers or can be integrated into IQF (Individual Quick Frozen) freezing systems.

Typically, tunnel freezers are designed to work with just one type of product at a time. They include an insulated housing to keep the products and cryogenic liquid at the correct temperatures. The freezer includes a conveyor belt by which the products are transported and an injection system that sprays the cryogenic liquid on the product to be cooled. The tunnel freezer also includes ventilation to control air flow and exhaust systems to vent the excess gas.

The most popular type of tunnel freezer is a straight-belt LN2 tunnel. These freezers spray the LN2 directly on the product to be cooled and force the cold vapor of the nitrogen gas back towards the conveyor entrance in order to extract as much refrigeration from the vapor as possible before exhausting it away from the freezer (a process known as vapor-stripping).

Another option is a flat-belt IQF tunnel. These freezers use a similar process as the straight-belt tunnel but use only vapor of the cryogenic liquid to freeze the product rather than spraying and forcing the vapor against the product. Flat-belt tunnels are usually used to process food products that have high water content, are very light in weight or are delicate in shape.

Our IQF tunnel freezers are engineered and built to your specific production needs. We can provide a single, modular freezer or multiple, staggered modules to meet the specific water content, weight, size, shape and fragility specifications of your product.

The best way to know whether a tunnel freezer is right for your operation is to speak with an expert. Our team of application engineers can help you decide what type and capacity of freezer is the best fit for your facility. We can also offer design assistance, installation, training and maintenance services. We’ve helped many customers save money and maximize their product quality by choosing the right tunnel freezer. To find out more about how we can improve your operation, contact us today. We’re ready to help you take your food processing to the next level.