Spray painting will result in a huge volume of hazards gas, especially for automated painting lines and paint curing furnace which are characterized by high air volume and low concentration. The odor of spray paint contains VOCs such as benzene, toluene, and xylene, which have a significant impact on the surrounding environment. Air volume calculation is a crucial point when programming a gas treatment solution. In actual condition there’s a few calculations in order to get the volume
Basic Method of Waste Air Volume Calculation
Air Volume = Booth Volume (Length x Width x Height) x Air Change Frequency (60-100).
The air change frequency 60-100 in the formula is an empirical value. If the spray booth operation time is short and the amount of paint sprayed is small, the value can be 60; if the operation time is relatively short and the amount of paint sprayed is small, the constant can be 70-80; if the operation time is long and the amount of paint sprayed is large, the constant can be 90-100 or even higher.
Calculation Method for Evaluating Exhaust Gas Capture Rate:
Calculate the fresh air volume as per workshop size by 60 times air changes per hour. The exhaust gas capture rate is the ratio of the actual organized exhaust air volume to the workshop’s required fresh air volume. Required fresh air volume = 60 x workshop area x workshop height.
Exhaust gas capture rate = Actual organized exhaust volume / Required fresh air volume.
Calculation Method of Spray Line Exhaust Gas Treatment Equipment Air Volume:
Equipment air volume = Exhaust cap area size (length x width) x a constant (2000-4000).
The constant 2000-4000 in the formula is empirical value. If the spray booth has short operating times and a small amount of paint, a constant of 2000 is acceptable. If the spray booth has relative short operating time and a small amount of paint, a constant of 3000 is acceptable. If the spray booth has long operating times and a large amount of paint, a constant of 4000 is acceptable.
Filtration air volume is one of the key parameters for selecting bag filters. It should be selected based on comprehensive consideration of various properties like particle size, temperature, and concentration of dust or smoke in different applications. Generally, when the inlet dust concentration is 15~30g/m3, the filtration wind speed should not be greater than 6~8m/min; when the inlet dust concentration is 5~15g/m3, the filtration wind speed should not be greater than 0.8~1.2m/min; when the inlet dust concentration is ≤5g/m3, the filtration air speed should not be greater than 1.5~2m/min.
