Spray gun clogging in fluid bed processing has three dominant causes — binder drying at the nozzle tip, particulate in the liquid line, and wrong gun-to-bed geometry. Fixes are mechanical: needle-valve anti-clogging tips, in-line filtration, and correct centering — not higher pressure.
The three causes
- Tip drying: binder skins over between spray pulses — worst with warm product air and long pause times.
- Particulates: suspension binder settles or carries lumps into the nozzle bore.
- Geometry: gun off-center to the Wurster partition or too close to the bed sprays onto hardware, building scale.
Fixes that hold in production
- Needle-valve tips that clear the orifice at every pulse end (Benelabo ELS-diPQ and SFPQ families).
- In-line filtration and continuous agitation of the binder suspension.
- Quick-detach nozzles so any blockage clears between batches, not during them.
FAQ
How often do spray nozzles need cleaning?
With needle-valve tips and filtered binder, cleaning is a between-batch task — typically at batch change — not a mid-batch stop.
Send your process question
Our engineers answer process questions within one working day — with numbers, not brochures.