Compression Unit Components Description; Oil Return Scavenge Window / Oil Return Scavenge Non - Return Valve - MIL'S AM 3 Notice D'utilisation

2.1. Compression unit components description
Air end (item 8)
The direction of rotation of the air end is to the left (anti‐clockwise) when looking from the front‐side on to the
shaft (see picture).
Pay attention to the directional arrow at the v‐belt pulley.
Suction air filter (item 6)
The suction air filter (with the small air end model NK 40 already integrated in the housing), is directly mounted
on to the suction stud of the suction regulator.
The dry micro‐filter with a rating of 10 µm filters the intake air.
Pressure switch (electric)
The pressure switch is directly connected to the outlet of the machine. It controls the suction regulator. The
values for pmax and pmin are set at this switch.
p : is the upper service pressure at which the unit normally stops pumping
max
P : is the lower service pressure at which the unit normally starts pumping again.
min
The pressure switch has been correctly set in the factory.
Authorised personnel must only carry out adjustments to the pressure switch.
Suction regulator
The suction regulator is directly connected to the air end. It controls the air volume sucked in by the
compressor via the air suction filter.
Function of the suction regulator:
The suction regulator comprises of one main valve. This
operates as a control valve and at the same time as a
hermetically sealed isolator valve. At full load the suction
cross‐section is fully opened.
When the machine stops this valve closes quickly and thus
the suction cross section is locked altogether.
The multi‐functions of the regulator are ensured by just one
flange mounted control unit.
Minimum pressure valve
The minimum pressure valve is situated at the outlet of the compressor unit just before the air‐after cooler.
It performs two tasks:
1) As a minimum pressure valve it prevents a loss of pressure (in the air end) when no counter pressure in the
air‐mains is available. A minimum pressure of 4.5 bar is necessary in order to safeguard lubrication of the air
end.
2) As a "non return valve" it prevents at the same time the reverse flow of compressed air from the air mains or
the air vessel, back into the compressor unit. Due to this function the compressor unit is totally pressure
relieved once it is stopped.
520513.01
AM3 – AM55
The valve operates automatically. The setting of the minimum pressure valve must only be done by persons
authorised by the manufacturer.
Oil separator cartridge (Item 7)
The oil separator cartridge is not only designed for filtering the oil from the compressed air, but serves at the
same time to reclaim the residual oil after pre‐separation as drops, formerly micro‐distributed in the system.
This cartridge is a spin on/off type and – by means of the connection nipple – is screwed on to the filter support
of the oil re‐claimer (see illustration below)
Illustration: oil separator cartridge
from
separator
2.1.1. Oil return scavenge window / oil return scavenge non‐return valve
The oil return window
(fitted to some air ends) is situated near to the oil separator cartridge and shows the scavenged oil coming from
the a.m. cartridge.
When starting the compressor the scavenge window is filled with oil due to its accumulation during standstill.
After a few minutes a mixture of oil and air can be observed. Separation of oil in the cartridge takes place.
If after a longer period of operating time no oil can be observed in the scavenge window, a disturbance may
have happened e.g. a clogged borehole. As a consequence the oil separated will be carried over in the
compressed air into the air mains/vessel.
Only personnel authorised by the manufacturer are allowed to rectify such problems.
The oil scavenge non‐return valve prevents the oil separator cartridge from flooding by scavenging oil from the
air end.
Oil filter (item 11)
The oil filter (cartridge) cleans the compressor oil from impurities. The cartridge is screwed on to the scavenge
stud by hand. The efficiency of the filter is between 5 – 10 µm.
Combistat
The Combistat is a temperature indicator and control unit. It is built into the instrument panel. It monitors the
maximum permissible service temperature of the unit, which is set at
110°C (red mark).
When this temperature is reached the electric circuit is disconnected and the unit stops automatically.
Do not bend the connecting line between the compressor and the Combistat, otherwise the electric circuit is
interrupted.
sealing
return oil
compressed air
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