Gardner Denver L160 110A V2, User Manual

Page: 22 / 72

3 Design and function
22 / 72 America January 2017
During screw compressor off-load operation,
a sufficiently large drop in pressure, and thus
the required oil injection volume, is achieved so
that negative pressure is produced at the intake
port and at the injection point when the suction
regulator is shut (-2-).
Excess pressure of approx. 1.5 bar/ 22PSI (off-
load pressure) is produced in the pressure vessel
at the same time.
3.5 Air circuit
The air drawn in reaches the screw compressor
(-4-) via the suction filter (-1-) and the suction
regulator (-2-). It is cooled by the injected oil
during the compression process. The ensuing
compressed air-oil mixture flows tangentially into
the pressure vessel (-6-). After the pre-separation
and the subsequent fine separation in the fine
separator (-7-), the low-oil compressed air reaches
the load network via the pressure-retaining and
non-return valve (-15-) and the air cooler (-16-).
3.6 Regulation
(Also refer to the operating instructions for the
compressor controller GD Pilot TS)
Unit standstill
•
During unit standstill times, the suction
regulator (-2-) is shut by a pressure string on
the adjusting cylinder (-2.1-).
•
The solenoid valve (-19-(Y1)) is currentless.
•
The pressure vessel is depressurised through
the blow-off valve (-20-) to atmospheric
pressure.
•
The cooling water solenoid valve (-xx-(Y6))
is shut in a currentless state (only L xxx W –
water-cooled systems).
Starting the unit
•
The motor starts up in Y-operation.
•
The cooling water solenoid valve (-xx-(Y6)) is
supplied with current and opens (only L xxx W).
•
The suction regulator is shut.
•
The compressor draws in air by means of an
adjustable throttle. Pressure builds up in the
pressure vessel.
•
Oil is supplied to the screw compressor due
to the drop in pressure between the pressure
vessel and the injection point in the screw
compressor.
•
When switching the drive motor to Δ-operation,
the solenoid valve (-19-(Y1)) switches, as it is
being supplied with current.
•
The air circulated in the system flows through
the solenoid valve (-19-(Y1)) into the upper
control space of the adjusting cylinder (-2.1-).
The blow-off valve (-20-(Y4)) shuts.
•
The throttle (-2.2-) in the suction regulator (-2-)
is opened.
•
At a vessel pressure of 4.5 bar / 65psi, the
pressure-retaining and non-return valve (-15-)
opens.
•
The supply of compressed air to the load
network begins.
•
The unit is in on-load operation.
Shutting the unit down
•
After pressing the OFF button on the control
panel of the GD Pilot TS compressor control,
the solenoid valve (-19-(Y1)) is switched to a
currentless state.
•
The upper control space of the adjusting
cylinder (2.1) is ventilated by the solenoid valve
(-19-(Y1)). The pressure spring in the adjusting
cylinder causes the throttle (-2.2-) in the intake
regulator to close.
•
After 30 sec. have lapsed, the drive motor
(-3-) and the cooling air fans (-17 and 25-) are
shut down. The cooling water solenoid valve
(-xx-(Y6)) is shut in a currentless state (only L
xxx W).
Automatic operation (OPEN-CLOSED
operation)
•
If the pressure at the line pressure sensor (-35-
(B1)) reaches the set upper switching point,
the solenoid valve (-19-(Y1)) is switched to a
currentless state.
•
The upper control space of the adjusting
cylinder (2.1) is ventilated by the solenoid valve
(-19-(Y1)). The pressure spring in the adjusting
cylinder causes the throttle (-2.2-) in the intake
regulator to close.
•
The pressure vessel is depressurised through
the blow-off valve (-20-) to off-load operation
pressure (residual pressure).
•
The screw compressor now runs in off-load
operation.
•
The cooling air fan (-25-) is switched on and off
based on the final compression temperature
(only L xxx fixed fan speed A – air-cooled
units).