Calculator
Coating drying capacity and maximum spray rate calculator
How much water your inlet air can actually carry away, and the spray rate that supports.
Result
- Ambient moisture
- 11.85 g/kgWater already in the air
- Exhaust moisture
- 28.34 g/kgWhat the air can hold on the way out
- Dry air mass flow
- 1,743 kg/h
- Drying capacity
- 479 g/min of water
- Maximum spray rate
- 563 g/minDispersion, at the solids above
Formula
saturation pressure, Antoine: log10 P = 8.07131 − 1730.63 ÷ (233.426 + T) humidity ratio W = 0.622 × Pv ÷ (P − Pv) drying capacity = dry air mass flow × (W exhaust − W ambient)
Why this number matters
This is the calculation that explains why a coating process that ran perfectly in February fails in July. The air can only carry away the difference between what it already holds and what it can hold at the exhaust condition. On a humid day that difference collapses, the bed stops drying at the spray rate you have always used, and you get picking and sticking on a formulation nothing has changed about.
Where it goes wrong
Treat the answer as a ceiling, not a setpoint. Run at 70 to 80 percent of it. And check it against the worst ambient humidity your site sees rather than today, because the process has to hold through the monsoon.
Other calculators
Every grade page carries the process parameters it was developed on, so you can start from a known point rather than a calculated one. Browse the grades.