Why Is Top Spray Fluid Bed Unsuitable For Coating?
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Jordan asked:
January 22, 2026 7:28 PM
Why Is Top Spray Fluid Bed Unsuitable For Coating?
Senieer Answered:
January 22 2026 8:30 PM
The coating effect of the top spray in the fluid bed is relatively poor. The reasons are as follows:
The fluidization motion state of particles is relatively irregular, so the adhesion of a few particles is often unavoidable, especially for the small particles.
In the reverse spray method, the coating liquid is sprayed against the particle movement direction. This increases the distance from the spray gun outlet to the particle surface. The incoming hot air may cause evaporation of the liquid droplets, potentially affecting their viscosity and film-forming properties. Poor process control could even lead to excessive spray drying of the coating liquid. Therefore, top spray technology should be avoided for organic solution coating whenever possible.
