User manual

Industrial Air Division
52920 1163 04
The oil system is provided with a by-pass valve (BV). When the oil
temperature is below 40°C (104°F) 1), by-pass valve (BV) shuts off
the oil supply from oil cooler (Co). Air pressure forces the oil from
air receiver/oil separator (AR) through oil filter (OF) and oil stop
valve (Vs) to compressor element (E) and its lubrication points. Oil
cooler (Co) is by-passed.
By-pass valve (BV) starts opening the oil supply from cooler (Co)
when the oil temperature has increased to the above-mentioned
value. At approx. 55°C (131°F) 1) all the oil flows through the oil
cooler.
Oil stop valve (Vs) prevents the compressor element from flooding
with oil when the compressor is stopped. The valve is opened by
element outlet pressure when the compressor is started.
1.1.3 Cooling and condensate drain systems
(Figs. 2)
The cooling system comprises air cooler (Ca) and oil cooler (Co).
On air-cooled compressors, the cooling air is generated by fan
(FN2). Water-cooled compressors have a cooling water system.
The water flows through inlet pipe (11), the tubestacks of the air
cooler and oil cooler, and outlet pipe (12).
A moisture trap (MT) is provided in the air outlet system. The trap
is equipped with a valve for automatic condensate draining during
operation (Da-Fig. 3) and a manually operated valve for draining
after stopping the compressor (Dm-Fig. 3).
1) The valve starts opening at 65°C (149°F) and is fully open at
80°C (176°F) for 13 bar and 175 psi compressors.
1.2 Unloading/loading system (Figs. 4)
1.2.1 Unloading (Fig. 4a)
If the air consumption is less than the air output of the compressor,
the net pressure increases. When the net pressure reaches the
unloading pressure, solenoid valve (Y1) is de-energized. The
plunger of the valve returns by spring force:
1. The control pressure present in the chambers of loading
plunger (LP) and unloading valve (UV) is vented to atmosphere
via solenoid valve (Y1).
2. Loading plunger (LP) moves upwards and causes inlet valve
(IV) to close the air inlet opening.
3. Unloading valve (UV) is opened by receiver pressure. The
pressure from air receiver (AR) is released towards unloader
(UA).
4. The pressure is stabilized at a low value. A small amount of air
is kept drawn in through flexible (3) and is also blown to the
unloader.
Air output is stopped (0 %), the compressor runs unloaded.
1.2.2 Loading (Fig. 4b)
When the net pressure decreases to the loading pressure, solenoid
valve (Y1) is energized. The plunger of solenoid valve (Y1) moves
upwards against spring force:
1. Control pressure is fed from air receiver (AR) via solenoid valve
(Y1) to loading plunger (LP) and unloading valve (UV).
2. Unloading valve (UV) closes the air blow-off opening. Loading
plunger (LP) moves downwards and causes inlet valve (IV) to
open fully.
Air output is resumed (100 %), the compressor runs loaded.
Da. Automatic condensate drain, air cooler moisture trap
Dm. Condensate drain valve, air cooler moisture trap
1. Pictograph, manual condensate drain
2. Pictograph, automatic condensate drain
3. Inlet for separate air dryer voltage supply
Fig. 3. Condensate outlets