Atlas Copco GA 11+ Instruction Book page 75

Instruction book
Q = (1.06 N + 1.2 D)/ΔT
v
Q = required ventilation capacity in m
v
N = nominal power of the compressor motor in kW
D = electric power of the dryer in kW
ΔT = temperature increase in the compressor room in C
For air-cooled compressors and ventilation alternatives 2 and 4
The fan capacity should match the compressor fan capacity at a pressure head equal to the
pressure drop over the air ducts.
Make sure that the cooling air duct of the air/oil cooler is separated from the cooling air duct of
the dryer.
For water-cooled compressors
The ventilation capacity required to limit the compressor room temperature can be calculated
from:
• For compressors without dryer:
Q = 0.13 N/ΔT
v
• For compressors with dryer:
Q = (0.13 N + 1.2 D)/ΔT
v
Q = required ventilation capacity in m
v
N = nominal power of the compressor motor in kW
D = electric power of the dryer in kW
ΔT = temperature increase in the compressor room in C
The cooling air of the dryer can be ducted outside
Air filtration
Filter DD to be installed for general purpose filtration (particle removal down to 1 micron with a
maximum oil carry-over of 0.5 mg/m³). A high-efficiency filter, type PD, may be installed
downstream of a DD filter. This filter traps solid particles down to 0.01 micron with a maximum oil
carry-over of 0.01 mg/m3. An UD+ filter leads to the same air purity as a DD filter combined with
a PD. If oil vapor and odors are undesirable, a QD type filter can be installed downstream of the
PD filter. All filters should be preceded by a water separator if no water separator is integrated in
the after cooler of the compressor. In case a dryer is preceding the filter, a water separator is no
longer required.
It is recommended to install bypass pipes with ball valves over each filter in order to isolate the
filters during service operations without disturbing the compressed air delivery.
The condensate collecting tubes should have a minimum length of two meter before they are
interconnected. After the interconnecting point, the drain tube requires twice the diameter of the
original tubes.
It is not allowed to connect pressurized electronic drains on the draining tubes of the filters.
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