Instruction book
909935AIB
19
Reference
Designation
A
ES4000T regulator
B
Unloader
C
To air cooler
D
Air receiver / Oil separator
E
To / From oil cooler
Regulating system
The compressor is controlled by ES4000T
regulator (A).
The regulator keeps the net pressure within programmable pressure limits by automatically
loading and unloading the compressor depending on the air consumption. It also protects the
compressor and monitors components subject to service.
Unloading
If the air consumption is less than the air delivery of the compressor, the net pressure increases.
When the net pressure reaches the upper limit of the working pressure (unloading pressure), the
following sequence will occur.
Step
Description
1
The load / unload control valve (1) opens and connects air receiver (D) and unloader
pressure chamber (2).
The blow-off valve (5) opens and releases air from the air receiver (D). Both the air
receiver pressure and the unloader chamber (4) pressure drop.
2
Driven by the pressure difference in unloader pressure chambers (2) and (4), unloader
plunger (3) moves downwards. This downward movement forces the unloader disc (6)
to close the compressor stage inlet.
3
The compressor stage keeps drawing in air through calibrated bypass holes in the
unloader disc (6) to maintain the unloading pressure level.
4
The air delivery stops, the air receiver (D) pressure reaches its stable unload pressure
level and air is being recirculated in the compressor.
The unload pressure level is necessary to guarantee the oil injection on a few critical
points (bearings, rotors, ...).
Loading
When the net pressure decreases to the lower limit of the working pressure (loading pressure),
the following sequence will occur.