Product Manual

10
EMAX Rotary Screw Compressors
4. Suction Valve
A butterfly valve that opens and closes during
operation. When PLC calls for air, the suction valve
opens through a solenoid valve to allow compres-
sor to operate. When air pressure reaches preset
max level, the PLC closes the suction valve allowing
compressor to pull vacuum and not compress air.
5. Regulation Modulation Control
This device is included on all 25-200 hp models as an energy
saving feature for applications with duty cycles of 50% or
more. The device keeps amp load lower by maintaining motor
operation so consistent air pressure is delivered under heavy
work loads. Units with lower duty cycles should use online/
offline (min./max. pressure) control. Both control methods
are available so appropriate feature can be selected for
different air demands. It is important to monitor air demand
since it takes 15% more power to operate compressor for every
10 PSI of pressure increase.
6. Air End
The air end has two rotor shafts mounted on
bearings parallel to each other in the machine
casing. The casing has an air inlet at the top
and an air outlet at the bottom. The shafts have
precisely machined, helical shaped screw threads
which work together to compress air. Air com-
pression occurs through a four course process:
1. Absorption
The position and shape of the rotor shafts
allow maximum air intake from the inlet port.
As the shafts turn, the air is forced to move
between the grooves of the screw threads.
2. Sealing and Conveyance
The air is sealed within the grooves of the screw
threads and conveyed, or moved, through the
machine casing toward the air outlet.
3. Compression and Lubrication
The rotor shaft screw threads are designed
with decreasing space between the grooves.
As the air is moved through them, it be-
comes pressurized and actuates the lubrica-
tion process. Lubricating oil is pressurized
and injected into the compression chamber
during operation for the following reasons:
a. To form protective film on rotors to avoid
contact and reduce friction.
b. To seal in the compressed air to improve
compressor efficiency.
c. To absorb heat to maintain optimal power.
d. To reduce operating noise.
4. Exhaust
When the air has reached the end of the
rotor shafts, it is fully pressurized and ex-
hausted into the air tank. As the rotors turn,
the compression process continues.
7. Exhaust Probe
The probe is temperature sensitive and located
at the air outlet of the rotary screw casing. When
exhaust temperature exceeds 210˚F (98.8˚C), the
system will automatically power OFF. The temper-
ature of the air exhaust can be read on a display
panel located on the PLC. Common reasons for
excessive exhaust temperatures:
 • lowoillevel
 • inoperableexhaustfan
 • improperventilationcausingambientair
temperature to be too hot
 • cloggedoillter
It is important to keep the circulating fan and
cooler fins clean to prevent the compressor from
shutting down. Low air pressure can be used
to blow them off or if needed, use water-based
solvent to clean.
8. Oil Cooler
The oil cooler function is to cool the hot oil from
compressor pump and return oil to the air oil
separator tank. It is important to keep the cooler
fins clean to prevent the compressor from high
temperature shut down. Low air pressure can be
used to blow them off or if needed, use water-
based solvent to clean.
9. Oil Filter
The oil filter is a paper filter with a filtration of
10 PPM. It removes impurities and protects the
bearings and rotors. The filter core should be
replaced every 2000 hours or annually, which-
ever comes first. Replace oil and filter after first
600 hours of operation. Refer to the computer
controls of the compressor to monitor operating
time and remember to reset to 0 when filter is
replaced. There is an automatic alarm that can be
set to remind operator of service times.
10. Air/Oil Separator Tank
The air/oil separator tank is a steel pressure vessel
used to store lubricating oil and to separate the
compressed air and the lubricating oil. An oil sight
gauge is installed on one end of the air/oil separa-
tor tank. Make sure oil level is at high oil level in-