A continuous flow
fluid bed dryer has a dryer housing having a drying chamber and a plenum chamber located beneath the drying chamber. Moist product to be dried is introduced to the drying chamber at a product inlet and proceeds through the drying chamber to a discharge housing. A porous screen partially separates the drying chamber and the plenum chamber. Heated air is introduced into the plenum chamber which then passes through the screen to the drying chamber to dry product in the drying chamber. A shaft extends centrally through the drying chamber and is mounted for slow rotation therein. A plurality of paddles are connected to the shaft. The paddles move about a path of rotation whereby paddle ends sequentially sweep over the surface of the screen. In doing so, the paddles momentarily move product away from the screen permitting a rush of heated into the drying chamber locally fluidizing the bed and further drying the product. The product is treated very gently in the process so as to suffer minimal degradation if any.
spray dryer
The invention pertains to a continuous flow
fluid bed dryer wherein portions of the bed are momentarily fluidized for drying purposes. The dryer includes a dryer housing having a dryer drum with a drying chamber, and a plenum section with a plenum chamber located beneath the drying chamber. Hot air is introduced into the plenum chamber. The lower part of the drying chamber is trough shaped with a curved bottom and relatively high side walls. A curved porous screen is located at the bottom of the drying chamber and permits hot air to be transferred from the plenum chamber to the drying chamber. A rotor shaft extends longitudinally through the drying chamber and carries a plurality of paddles. The shaft rotates slowly in the drying chamber to gently mix the product with the heated air and advance it downstream in the chamber. As each paddle sweeps across the screen it moves product away from the screen. This permits a momentary rush of air through the screen, locally fluidizing the product and promoting drying.
Referring to the drawings there is shown a
fluid bed dryer according to the invention indicated generally at 20. Dryer 20 includes an elongate dryer housing 21 disposed about a longitudinal axis and connected to a product inlet chute 22 at a first or upstream end, and a discharge housing 24 at a second or downstream end. Product to be dried is carried to the inlet chute 22 by suitable conventional or preferred means such as an auger indicated at 23 in FIG. 1. Product leaves dryer housing 21 through a product outlet opening 33 (FIG. 6) to enter discharge housing 24.
drum dryer
