Fluidized Bed Freezer – Chilled Air
Industry: Fruit and Vegetables (NAICS 3114)
Process Brief: Fruits and vegetables are frozen quickly using chilled air
Energy source: Electricity/ some Natural Gas
Energy Intensity: 250-1,700 Btu/lb of product
Fluidized bed freezers were developed to yield a better quality product than could be produced using plate or tunnel freezers. A major problem with other freezer designs is that the product tends to freeze in clumps, making further processing difficult. Breaking apart the clumped frozen product caused considerable product degradation and added steps to the production process. Fluidized bed freezers were developed in the 1960s to quickly freeze fruits and vegetables without clumping. The product is piled 4-6 inches deep on a perforated tray or conveyor, and upward-flowing chilled air entrains the individual pieces and freezes them. The continuous movement helps to prevent clumping and speeds freezing.
The air is cooled using mechanical (electricity) or thermal (natural gas) methods. Heat transfer rates are about five times the rates for tunnel or spiral belt freezers and vegetables can be frozen is less than five minutes. The disadvantages of fluidized bed freezers are the need for the product to be small enough to be fluidized and some higher operating costs than tunnel or belt freezers.
FMC FoodTech Chicago
200 East Randolph
Chicago, IL 60601
Web site: www.foodtechnologies.com
2411 Vauxhall Place
Richmond BC, V6V 1Z5 Canada
Web site: www.advancedfreezer.com
Source: Overview GRI-03/0075; Overview image from FMC at http://www.fmctechnologies.com/upload/flofreeze_b3001_en_0201.pdf