2920 1462 00
18
Instruction book
1.5 Air dryer (Fig. 1.7)
GA Workplace FF and GA Pack FF are provided with a dryer
which removes condensate from compressed air.
1.5.1 Compressed air circuit
Compressed air enters heat exchanger (33) and is cooled by
the outgoing, dried air. Moisture in the incoming air starts to
condense. The air then flows through heat exchanger/evaporator
(31) where the refrigerant evaporates causing the air to be
further cooled to close to the evaporating temperature of the
refrigerant. More water in the air condenses. The cold air then
flows through separator (25) where all condensate is separated
from the air. The condensate is automatically drained. The
cold, dried air flows through heat exchanger (33), where it is
warmed up by the incoming air.
1.5.2 Refrigerant circuit
Compressor (38) delivers high-pressure refrigerant gas which
flows through condenser (29) where most of the refrigerant
condenses. The liquid flows through liquid refrigerant dryer/
filter (32) to capillary tube (27). The refrigerant leaves the
capillary tube at evaporating pressure. The refrigerant enters
evaporator (31) where it withdraws heat from the compressed
air by further evaporation at constant pressure. The heated
refrigerant leaves the evaporator and is sucked in by the
compressor.
By-pass valve (30) regulates the refrigerant flow. Fan (37) is
switched on or off by switch (39) depending on the loading
degree of the refrigerant circuit.
The compressor motor has a built-in thermic protection. In
case the compressor motor stops after tripping of the thermic
protection, it may take up to 2 hours to cool down the motor
windings.
2 Installation
2.1 Dimension drawing (Fig. 2.1)
See opposite page.
2.2 Installation proposal (Fig. 2.2)
See page 20.
Ref. Description/recommendation
1 Install the compressor on a solid, level floor suitable
for taking the weight.
2 Position of the compressed air outlet valve.
3 The pressure drop over the delivery pipe can be
calculated as follows:
dp = (L x 450 x Qc
1.85
) / (d
5
x P)
dp = pressure drop (recommended maximum = 0.1
bar)
L = length of delivery pipe in m
d = inner diameter of the delivery pipe in mm
P = absolute pressure at the compressor outlet in
bar(a)
Qc = free air delivery of the compressor in l/s
It is recommended that the connection of the compressor
air delivery pipe is made on top of the main air net pipe
to minimize carry-over of possible remainder of
condensate.
4 Ventilation: the inlet grids and ventilation fan should be
installed in such a way that any recirculation of cooling
air to the compressor or dryer is avoided. The air
velocity to the grids must be limited to 5 m/s. The
maximum allowable pressure drop over the cooling air
ducts is 30 Pa. If exceeding this value, a fan is needed
at the outlet of the ducts. Consult Atlas Copco.
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