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Linxis Group

The DIOSNA glossary

Technological terms in an overview



Abbreviation of Fluid Bed Dryer.


Federal Drug Administration: Food and Drug Authorities in the United States

FDA compliant

Meeting the requirements and prescriptions of the FDA.

Film coating

Coating of e.g. tablets with polymer layers.

Fluid Bed

Condition in which the fine grained solid particles of a bulk good are loosened up and carried by an upwards directed gas stream from a certain gas velocity on. The weight of the particles is compensated by the contrary flow force of the gas. The former bulk good behaves similar to a liquid (fluid bed). The fluid bed creates ideal conditions for heat and mass transfer processes.

Fluid Bed Coating

A particle (e.g. pellet, granule) is covered with a layer in a fluid bed process to achieve certain functional characteristics. Usually the layer is sprayed onto the particle with one or various nozzles. The most important feature of coating is the uniform application of the layer. Fluid bed coating can be realized by top-spraying (irregular layer), tangential spraying or bottom spraying (Wurster).

Fluid Bed Coating Bottom Spray

Coating process in which the coating suspension is applied from below through a nozzle installed in the bottom plate. This coating process is either realized by a so-called Wurster device, or the particle movement is created by a special bottom perforation blowing inside with a central nozzle insert.

Fluid Bed Dryer

Dryer in which the moist product is set into fluidisation by heated drying air. The air passes the material from below through an air distributing plate. This drying principle is extremely efficient because of very intensive heat and mass transfer conditions, but it only works with fluidisable products.

Fluid bed Granulation Top Spray

Formation of granules resp. agglomerates from a fine grained product by the fluid bed technology. The powder is set into the condition of the fluid bed and sprayed with water or a binder solution from above (top-spraying). Thus a repeated process is created consisting of defined wetting of the product and subsequent drying. This results in the formation of solid bridges forming granules. Because of the intensive mixing within the fluid bed a very uniform particle structure is built. The fluidising particles are very well accessible for the binder spray. Their steady movement reduces the risk of sticking together.

Fluid Bed Granulator (FBG)

Fluid bed plant which is not only suitable for drying but also for spraying binder liquid. A fluid bed granulator can be provided with a top spraying device, tangential spraying device or bottom spraying device. Depending on the chosen procedure slightly different process and product qualities are achieved.

Fluid Bed Spray Granulation

Formation of granules resp. agglomerates of fine grained product by the fluid bed technology. The powder is set into the condition of a fluid bed and is sprayed with water or a binder solution. The spraying can be effected from above (top- spraying), laterally (tangential-spraying) or from below (bottom-spraying). Spray granulation in the fluid bed is a repeated process consisting of defined wetting of the product and subsequent drying. This results in the formation of solid bridges forming granules.

Fluid Bed Processor

Fluid bed plant in which various fluid bed processes can be realised, such as drying, granulating and coating.

Fluid Bed System

A fluid bed plant consist of the fluid bed batch processor as principal item as well as of peripheral equipment such as inlet air handling, exhaust air handling and controls which are necessary to run the machine.

Fluid Bed Tangential Spray

This version of a fluid bed process allows the lateral spraying of the liquid, quasi tangentially to a circular line on the bottom plate. For this process usually a special air distributor plate is used which sets the product into rotating movement. Together with the atomizing air of the tangentially installed spraying nozzle a rotating movement of the bed is created resulting in a smaller vertical bed expansion. The granules produced in this process tend to be more dense and compact than those produced in a top spray process.

Fluid Bed Technology

Fluid bed technology describes the coherences which lead to the so-called fluid bed when gas streams through a fine grained packed bed. The condition of the fluid bed creates a maximal product surface which allows extremely effective heat and mass transfer processes resulting in high-efficient drying processes.

Fully perforated Drum

Vertical or horizontal coating plants are equipped with an air ventilated process chamber to dry the coated tablets. The drums can either be designed with a complete perforation or a partial perforation. The completely perforated drum offers a maximal free surface and reduces the flow velocity of the air when entering.

Functional coating

A functional coating on a pellet, granule or tablet is made for a special intended purpose such as protection against humidity, solar radiation or similar which might cause a modification of the primary substance. A functional coating can have further, very special characteristics, e.g. it may cause a delayed release of the active ingredient. On the other hand purely cosmetic coatings are made to create an optically attractive product.