The Lödige fluid bed processor is designed for drying, instantizing, granulating and coating. The processor runs in batch operation. The heated inlet air flows homogeneously through the special designed Conidur® bottom into the product vessel, fluidises the product and keeps it in constant motion. This ensures excellent heat transfer and a high drying rate. Integrated jet filters separate the product area from the pure gas area. The product particles are held back in the processor and retained in the process. The process air leaves the processor at the top.
For extremely complex applications or sensitive products such as active ingredient granulates, the fluid bed principle is the processing equipment of choice. With the fluid bed principle, the product bed is fluidised in the airflow and sprayed with the desired film former until the desired degree of coating is achieved. As a general rule, the coating substance is dissolved in a suitable solvent and sprayed in a fine mist. In the fluid bed, the liquid drops moisten the particle surface. Simultaneously, the solvent is dried by the fluidization air, so that the coating substance stays on the surface of the particles to achieve the desired effect.
Specially designed for pharmaceutical applications
In the pharmaceutical industry, the fluid bed process is used, for example, to encapsulate and thus protect ingredients. For pharmaceutical applications, Lödige Process Technology offers the fluid bed processor. The latter can be configured to suit the application: the system’s product vessel is equipped with so-called bottom-spray nozzles, specially designed for the coating of pellets or mini-tablets. Lödige has implemented this principle with tangential nozzles. They enable the addition of coating liquid directly into the product bed. In this way, the same processes can be performed as with the Wurster technique, without the need for additional liquid.
Thanks to a wide range of available options, the fluid bed processor can be tailored to the customer’s requirements and conditions. For example, when granulates are to be formed by liquids containing solvent this can generate a potentially explosive atmosphere in the processor. In such cases, the air unit, processor and controls are customised to ensure safe operation (flameproof). As filters cannot always be reliably cleaned with a washing-in-place system, they are dismantled and washed separately. The processor itself is automatically cleaned by cleaning nozzles. The filters are then remounted. This process can be validated (WIP system).