FLUDIZED BED DRYER ( FBD )

Presentation – 

Liquid bed drying is the most broadly utilized procedure for drying pharmaceutical powders and granulation. 

The immediate contact among particles and air/gas is conceivable in a liquid bed framework. 

Here a dormant gas or air is utilized. 

They can be structured in either group or ceaseless sort liquid bed dryer. 

In a fluidized bed dryer, hot air is passed at high weight through a punctured base of the holder containing granules to be dried. 

The granules are lifted from the base and suspended in the flood of air. 

The hot gas encompassing each granule to totally dry them. , 

Hence material or granules are consistently dried. The hot air/gas utilized for drying can be created by either steam curls or an ignition heater. 

The point of rest of the gas-strong blend is zero and it accepts the state of the vessel that contains it. 

WORKING – 

At the point when the speed of the air is more noteworthy than the settling speed of granules, the granules remain incompletely suspended in the gas stream. 

After some time, a state of weight is reached at which frictional drag in the particles is equivalent to the power of gravity. 

The granules ascend in the compartment on account of high-speed gas and fell in an irregular bubbling movement. 

This condition is supposed to be a fluidized state. 

Drying is accomplished at a consistent rate and the falling rate period is short. 

Sort OF FBD – 

A) Batch Type Vertical Fluid Bed Dryer - 

1. Reverse Turning Bed Type In this gear, by turning the gas scattering plate (the converse turning bed) in 90° course with the control engine, all the dried material can be released without a moment's delay. 

2. Rotating Discharge Type Dried material is released by opening the release entryway prepared along the edge of the Dryer. As the punctured plate is utilized as the gas scattering plate, the gas inside the gear spins and pushes the dried material out from the release entryway. 

B) Continuous Type Horizontal Vibrating Conveyor FBD 

Habitation time in any drying zone is reliant on 

(1) Length of the zone 

(2) The recurrence and the sufficiency of the vibration 

(3) Use of dams 

Warmth move units, for example, cylinder or plate, are worked inside the hardware. 

This unit supplies 60-80 % heat fundamental for drying 

Sorts of the processor – 

I. Top splash 

II. Bottom splash 

III. Tangential Spray 

TOP SPRAY – 

It is the straightforward liquid bed as a rule with a cone-shaped shape at the base of the chamber. The splash is provided from the top toward the fluidized bed agglomeration. Elutrited particles from the liquid bed are tapped generally by the pack channel and came back to the bed by periodical shaking of the sack channel with or immediately of fluidization air info and shower in the agglomeration yet consistently without pause in the covering 

Extraneous splash – 

This spout presented at the site of the item processing container.During three mechanical powers cause molecule moving blending and turning of granulation. The first circle generates radial for secondly lifting process is generated via air volume that passes through a flexible plate gap. Third gravity causes the material to tumble down 

Bottom shower – 

Created by dr dale Wurster in late 1950. The spout is mounted at the base of the item holder and is centered in the covering zone. The qualities of the wurster procedure make it feasible for the covering and agglomeration of the better molecule 

Points of interest – 

A fluidized bed dryer requires less of an ideal opportunity to finish drying. i.e., 20 to 40 min. 

Problem areas are not seen in the dryer, as a result of its superb blending and drying limits. 

The warm proficiency is 2 to multiple times more prominent than the plate dryer. 

It encourages the drying of thermolabile substances since the contact time for drying is short. 

It tends to be utilized either as clump type or constant sort. 

The free development of individual particles wipes out the danger of solvent material moving as may happen in a static bed. 

Burdens - 

The choppiness of the fluidized condition of granules may cause the wearing down of certain materials. 

Molecule separation is normal. 

Funnel and vessel dividers are dissolved because of impact of a molecule.