A particle injection system for a fluid bed dryer includes a product injection tube
inserted into a product containing fluid bed chamber of the dryer for injecting particulate material in a fluidized stream into the chamber of the fluid bed dryer while the dryer is in operation.
In a fluid bed dryer having a fluidizing chamber adapted to contain an easily agglomeratable material in particulate form and means for drawing a current of air through said fluidizing chamber to fluidize and dry said material and create a subatmospheric pressure within said fluidizing chamber, the improvement comprising: injector means for injecting said particulate material in a confined fluidized stream into said fluidizing chamber, said injector means comprising a short tubular element inserted into and communicating with said fluidizing chamber and terminating external to said fluidizing chamber in a funnel shaped collection means open to the ambient atmosphere surrounding said fluid bed dryer wherein said particulate material is introduced into said funnel shaped collection means and transferred into said fluidizing chamber by an air pressure differential between said fluidizing chamber and said collection means so that said particulate material is introduced into said fluidizing chamber in a fluidized state to remain in a particulate form and enhance the drying operation.
Although the rotating disc dryer is a notable improvement over prior art fluid bed dryer, it only partially overcomes the problem of initial agglomeration which occurs when certain products are loaded into the product containing chamber of the fluid bed dryer in the conventional batch loading step. The initial agglomeration which occurs due to the batch loading of cheese, yeast or other soft particles frequently is not entirely broken up by the agitation in the ordinary operation of the rotating disc dryer. Thus, initial agglomeration results in nonuniformly dried products and a lack of uniformity in the particle size of the product due to the presence of agglomerates even in this improved prior art dryer.