Process advantages
Uniform, continuous product coating. Aqueous or organic coatings
can be applied. Coating and drying take place in one machine.
In terms of Total Containment,
the coating process and the filling and emptying of the machine
can be carried out in complete isolation and without product spreading
into the environment.
When using organic solvents, the process machines can also be made
inert and used with a solvent
recovery system.
Principle of operation
With fluid bed coating, particles are fluidized and the coating
fluid sprayed on and dried. Small droplets and a low viscosity of
the spray medium ensure an even product coating.
Glatt offers Batch
Fluid Bed Systems in different batch sizes with:
Principle:
Batch fluid bed coating
Top Spray |
Principle:
Batch fluid bed coating
Bottom Spray
(Wurster coating) |
Principle:
Batch fluid bed coating
Tangential Spray
(Rotor pellet coating) |
Glatt offers Continuous
Fluid Bed Systems for different throughputs with:
Principle:
Fluid bed coating in the
continuous Glatt fluid bed:
Top Spray
|
Principle:
Fluid bed coating in the
continuous Glatt fluid bed:
Bottom Spray
|
Top Spray Coating
This process is used for general coatings right up to enteric coating.
With top spray coating in the fluid bed (batch and continuous),
particles are fluidized in the flow of heated air, which is introduced
into the product container via a base plate.
The coating liquid is sprayed into the fluid bed from above against
the air flow (countercurrent) by means of a nozzle. Drying takes
place as the particles continue to move upwards in the air flow.
Small droplets and a low viscosity of the spray medium ensure that
the distribution is uniform.
Coating in the continuous fluid bed is particularly suitable for
protective coatings/colour coatings where the product throughput
rates are high.
The product is continuously fed into one side of the machine and
is transported onwards via the sieve bottom by means of the air
flow. Depending on the application, the system is sub-divided into
pre-heating zones, spray zones and drying zones. The dry, coated
particles are continuously extracted.
Bottom Spray Coating (Wurster coating)
This process is particularly suitable for a controlled release
of active ingredients.
In the Wurster process, a complete sealing of the surface can be
achieved with a low usage of coating substance.
The spray nozzle is fitted in the base plate resulting in a spray
pattern that is concurrent with the air feed. By using a Wurster
cylinder and a base plate with different perforations, the particles
to be coated are accelerated inside the Wurster tube and fed through
the spray cone concurrently.
As the particles continue travelling upwards, they dry and fall
outside the Wurster tube back towards the base plate. They are guided
from the outside back to the inside of the tube where they are once
again accelerated by the spray. This produces an extremely even
film. Particles of different sizes are evenly coated.
Bottom Spray Coating (Continuous fluid bed)
Particularly suitable for protective coatings/colour coatings where
the product throughput rates are high.
The product is continuously fed into one side of the machine and
is transported onwards via the sieve bottom by means of the air
flow.
Depending on the application, the system is sub-divided into pre-heating
zones, spray zones and drying zones whereby spraying can take place
from below in the form of a bottom spray. The dry, coated particles
are continuously extracted.
Tangential Spray Coating (Rotor pellet coating)
Ideal for coatings with high solid content.
The product is set into a spiral motion by means of a rotating base
plate, which has air fed into the powder bed at its edge. The spray
nozzle is arranged tangentially to the rotor disc and also sprays
concurrently into the powder bed. Very thick film layers can be
applied by means of the rotor method. See also
->
Fluid Bed Pelletizing
| 
