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
| Blade form | Backward inclined or backward curved; the residual dust does not justify a radial wheel |
| Material of construction | Mild steel |
| Drive and bearings | Direct coupled or belt driven; belt drive where the duty point may need tuning at site |
| Also specified | Spark resistant construction with non-ferrous rubbing parts, shaft seal, earthing and a flameproof or increased safety motor; access doors on the scroll and a wheel that can be cleaned in place |
| 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 centrifugal impeller without a scroll, plugged through the wall of an oven, dryer or air handling unit so it recirculates the air inside the chamber. Belt driven or direct driven from outside the hot zone. Client-stated blade types for the Plug Fan in general: Backward curved.
Industries
Other fans in automotive paint shops
Plug Fan in other processes
Heat Treatment FurnacesGlass Forming and Annealing LehrsCeramic Tunnel and Roller KilnsBelt and Tray DryersFood Ovens and FryersTextile Stenters and DryersPowder Coating Lines
Information needed to select or quote
- Duty point. Volume flow and static pressure at the fan inlet, with the gas density and temperature or the conditions to derive it.
- Operating conditions. Site altitude, normal operating temperature and continuous or intermittent duty.
- Gas stream. Dust loading and particle size, corrosive species, moisture, upset temperature and any tendency of the material to deposit on the impeller.
- Mechanical. Rotation viewed from the drive end, discharge orientation and motor power.