Installation Manual Series CF (excluding encapsulated screw compressors) 23042013 Rev. A / May 2007 15 of 60
4.4 Recommendations for plant
protection
Maximum permissible discharge temperature:
110 °C. Temperature monitoring is prescri-
bed.
Minimum permissible discharge pressure:
6 bar (with opened suction valve)
Maximum permissible discharge pressure,
see technical data sheets.
The minimum discharge temperature should
be above the dew point temperature. If this is
not the case, the water vapour contained in
the air condenses. The water accumulating in
the oil affects the lubricant and may lead to
bearing damages.
Existing adjustment possibility for the oil in-
jection amount to influence on the discharge
temperature.
The system must be designed so that, when
the motor is at standstill, any still existing
pressure cannot relieve backward through
the compressor unit (reverse motion of com-
pressor) or through oil system (compressor
fills with oil; risk of liquid hammer when start-
ing-up again).
Generally, the unit does not require an oil
pump. It is sufficiently supplied with oil due to
the pressure differences between the oil res-
ervoir that is under discharge pressure, and
the individual connection points. For particu-
lar operating conditions (e.g. extremely low
temperatures or pressures <6 bar), sufficient
oil supply must be ensured by means of an
external oil pump.
The size of the oil reservoir/coarse separator
is decisive for the degree of preliminary sepa-
ration of the oil from the compressed air. A
large reservoir means a low flow speed and
thus a good oil separation. The build up the
required lubrication oil pressure as rapidly as
possible at start-up, a minimum pressure
valve should be fitted behind the separator
ahead of the mains.
At every stage of run-up, the starting torque
of the motor must be higher than the starting
torque of the compressor. The run-up time of
the motor should not be less than 2 seconds.
Drive motor has to be designed that no axial
force can affect jackshaft of compressor. To
compensate magnetic forces and forces caused
by heat expansion the motor bearing on the cou-
pling side has to be designed as fix bearing. Axial
forces can damage gears in a gear box driven
airend!
Short interruption of operation caused by voltage
break-downs of the electric power create dy-
namic processes within the drive train with high
loads exceeding several times the nominal loads
which causes overheating of the drive train and
its damage. Warranty claims caused by this kind
of damages will definitively be rejected!
Motor, coupling, gear box/belts and airend com-
bination, could create a situation resulting in a
package susceptible to damaging vibration fre-
quencies. To ensure safe and free of vibration
operation of the system, torsional vibration
analysis must be undertaken. The motor and
airend frequencies have to be considered in this
calculation.
Airend Installation
When loading or transporting airends ensure that
the specified lifting and tie down points are used.
It is recommended that the machine be moved
using the fork lift slots in the airend. The airend
has to be installed without any restraints. Be-
cause of acoustic reasons vibration-free installa-
tion has to be considered (avoidance of struc-
ture-borne noise)
Synthetic components in compressed air units
might be corroded by synthetic lubricants or addi-
tives contained in mineral lubricants. Compatibil-
ity has to be checked regarding utilisation of lu-
bricant. We recommend coolant „PrimeCool“ or
„PrimeCool Plus“.
Compressed Air Piping
The compressed air piping should have at least
the same diameter as the discharge port of the
compressor. All pipes and fittings have to be de-
signed and built according to the max. discharge
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