The process
A paint shop is an air system: conditioned supply through AHUs to the booths, exhaust with overspray through water wash or dry filters, solvent abatement by adsorption or oxidation, and ovens with recirculation fans. Spark resistant construction on the exhaust side.
The gas at the fan
Booth exhaust carries paint overspray that cures on anything it lands on, with solvent vapour. Spark resistant, a blade form that is easy to clean, and the fan after the booth filters or scrubber.
Selection for this duty
| Construction | Axial fans in weatherproof cowls, or supply and exhaust units with filters as the air quality requires |
| Density at the fan | At about 35°C the gas density is close to 1.15 kg/m³, 95% of standard air. Pressure developed and power drawn fall in the same ratio, so the selection is made at this density and the motor is checked at cold start. |
A packaged unit with fan, filters, cooling or heating coil and mixing box that conditions and delivers supply air. Pre, fine and HEPA filters as the air quality requires. Client-stated blade types for the AHU in general: Backward curved and forward curved.
Industries
Other fans in automotive paint shops
AHU in other processes
Information needed to select or quote
- Gas volume and temperature. Actual flow at the inlet, normal and upset temperature, moisture.
- Dust or pollutant. Inlet loading, particle size distribution, whether it is abrasive, sticky, hygroscopic or combustible; for gases, the species and concentration.
- Required outlet. The emission limit or clean gas concentration the unit must meet.
- Site. Available space and height, material of construction preferences, and how the collected material is to be discharged.
