Each IQF tunnel is designed in modular sections, called plenums.

 

The air is divided inside the IQF system by the plenums, preventing the air from transferring down the tunnel to a hole or weak area in the product surface. When the air is restricted from passing throughout the IQF tunnel length, less product blowoff is achieved.

 

Large fan plenum doors are adjustable, allowing belt bypass capability. This, too, will assist in achieving optimum dense phase suspension, minimizing blowoff of product fines.