The food particulates generally of a uniform size are placed on a mesh conveyor, the airstream is in an upward direction and the velocity of the air is adjusted to just lift the product off the belt and this also causes the product to flow. There is a change in the elevation of the conveyor, the solid particles begin to act like a fluid as they are submerged in the air
As the product moves in the fluidized bed, it comes in good contact with the air, there is an excellent heat transfer between air and product.
One can achieve convective heat transfer coefficients of between 30 and 60 w/m2k.
The product remains separated during freezing, as each particulate is lifted off the belt and tumbles in the air. It freezes while remaining separate from neighboring particles. Particulates are frozen in an individual manner, and we call it IQF. We can get similar results on a regular belt freezer, but in a fluidized bed you have better separation of the particulates and individual quick freezing
Some of the common products that are frozen in a fluidized bed freezer are strawberries, blueberries, diced meat, peas, beans and French fries.
The product is evenly overlaid on the fluidized belt and floating in the air.
The product is in good contact with the air, with excellent heat transfer between air and product. Convective heat transfer coefficient between 30-60w/m sq.k.The products remain separated during freezing. Minimum product water loss, and high product quality. Large freezing capacity up to 6 tons/hr.Relatively small equipment footprint versus capacity.
The pulse vibrator agitates the belt to prevent the products from sticking to the belt. Ideal for strawberries, blueberries, diced meat, peas, beans and French fries.
- The food particles act like fluid which is a condition where the solid particles are mobile and in semi-suspended condition, The high-speed air is directed vertically upward through the mesh conveyer carrying the product through the system.
- The two-stage fluidized bed freezer features two sections. The first is a fluidization section where the air blast is sufficiently strong to lift the product. The purpose of this section is rapidly to freeze the surface of individual particles so as to form a crust and prevent adhesion. The rapid formation of a frozen crust also reduces moisture loss. The interior of the particle is still unfrozen. Freezing is completed on a belt at the second section, without fluidization
- Excellent heat transfer between air and product.
- The product remains separated during freezing.
- The product tumbles in the air.
- Is ideal for freezing particulate foods such as peas, cut corn, diced carrots, strawberries, mango dice, etc
High pressure and high-speed airflow make the frozen products good fluidization.
Frozen products are “lifted” by airflow which will not be subjected to severe impact. The breakage rate is low.
Frozen particles are “wrapped” by the airflow and separated.
Different applications on vegetables and fruits by IQF freezer
Working principle video
For the working principle of the IQF freezer, please visit the video https://www.youtube.com/watch?v=NDH6UuUl_6M