How a Downdraft Paint Booth Clears Overspray
In a downdraft booth, filtered ceiling air moves around the vehicle toward floor collection areas. The plenum, workpiece, floor filters and supply/exhaust balance shape that route. This film illustrates spray mode with two floor collection rows.
Follow the air through the process
Spread clean air across the ceiling
The supply fills an overhead plenum, then passes through the ceiling filters into the work area.
Follow the route around the body
Air divides around the roof and sides. In this example it continues down beside the vehicle toward two floor collection rows.
Collect overspray at the floor
Paint particles reach the floor-filter media while air continues into the exhaust route. Capturing particles does not establish removal of all solvent vapor.
Coordinate supply with exhaust
Both duties must account for filter loading and the booth pressure balance. A large free-air fan rating alone does not define useful booth airflow.
Airflow function
- Feed the ceiling plenum with clean supply air.
- Support distributed airflow around the vehicle toward the floor collection areas.
- Coordinate supply delivery with exhaust and changing filter resistance.
What can change the result
- A poor distribution layout can leave parts of the workpiece without the intended flow route.
- Loaded filters can change the delivered flow and booth pressure balance.
- Treating particle filtration as complete vapor removal misses a separate part of the exhaust assessment.
Start with the complete air path
Share your layout and the information you already have. Unknown values can be identified before a configuration is selected.
Match the fan to this air path
Consider LONGWELL multiwing centrifugal families for suitable clean supply-air assemblies. Start with the plenum, filters and installed supply duty; assess contaminated exhaust separately.
Where it sits
In a suitable clean-air supply assembly feeding the ceiling plenum and intake filters. The contaminated floor-exhaust branch is assessed separately.
Why consider this configuration
The supply fan must overcome the inlet filters, plenum and distribution losses while coordinating with exhaust. Its duty is defined by the installed booth, not a free-air fan rating.
Check the result in your equipment
Application questions
Why does the vehicle shape matter?
The body redirects the air around its roof and sides. A useful supply layout must reach those spaces and connect to the floor collection route.
Do floor paint filters remove every solvent vapor?
The depicted media collects overspray particles. Particle capture does not establish removal of all solvent vapor.
Is the pictured fan proposed for the contaminated exhaust?
No. This selection discussion is limited to a suitable clean supply-air duty; the exhaust needs a separate equipment-specific review.
Discuss your clean supply-air duty
Share the spray-mode booth and ceiling-plenum layout, filter losses and supply/exhaust duties. Identify the fan location and inlet conditions for a clean supply-air review.
A layout, installation photos or your existing model is enough to start the discussion.