ELGi EN 30X-100, Инструкция по эксплуатации, техническому обслуживанию и запасным частям

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2.9
General functional description
2.4.1 Air circuit
Atmospheric air enters into the airend through the air
intake system. The intake filters (pre filter and air filter)
prevent the entry of foreign particles (such as dust) into
the airend. Dust and micro particles above 10 microns are
separated by the pre filter and particles above 3 microns
are filtered off by the air filter. The intake valve regulates
the amount of air sucked into the airend. The opening and
closing of the intake valve is controlled by the pneumatic
pulse line actuated by the electrically controlled solenoid
valve.
The filtered air enters into the airend where it mixes with
the injected oil. The injected oil acts as a coolant to
maintain optimum temperature. It also seals the leaks
between the rotors and the housing and lubricates the
bearings and gears. The airend consists of two counter-
rotating intermeshed helical screws — the male and
female rotors — which are driven by an electric motor. The
air-oil mixture is trapped between the rotors of the airend
and is progressively compressed.
After being compressed, the air-oil mixture enters into the
air-oil separator tank, with high velocity, where it
undergoes a unique 3-stage separation process to remove
maximum oil content. This highly efficient 3-stage
separation process uses the impact velocity of the air-oil
mixture along with the OSBID process to make the
mixture very lean. The final stage of this separation
consists of passing the lean mixture through the air-oil
separator element to ensure an oil content of 3 ppm and
less in the air.
The oil separated and collected in this element is then
returned to the airend through the scavenging line. The air
passes through a minimum pressure valve (MPV). It
maintains a minimum differential pressure required for
circulation of oil within the compressor unit. The
compressed hot air is cooled in the after-cooler. .
2.4.2 Oil circuit
The separated oil in the air-oil separation tank flows into
the airend. The oil either diverts to the oil cooler or oil
filter or both depending upon the temperature. The
thermal valve governs and controls the oil flow path. The
oil before being injected into the airend is filtered. An
orifice residing in the oil flow path towards the airend
controls oil flow. Any small quantity of oil, separated and
stored in the separator element, enters into the airend
through the scavenging line. The whole oil circulation
circuit in the compressor is operated solely by the
differential pressure maintained by the minimum pressure
valve (MPV) and doesn't require any additional pump.
2.4.3 Drive system
The airend is powered by an electric induction motor
through a belt and pulley. When the compressor is turned
ON, the motor is started in star mode and it takes 6 to 9
seconds to change over to delta mode. During this period,
the intake valve closes and thus the motor starts without
load. In delta mode, the motor speed stabilizes, the
solenoid valve energizes after 10 seconds of changeover to
reduce motor load, the blow down valve closes, the intake
Functional description 2.4
Figure 1. Screw compressor systems - Schematic diagram