The purge flow pressure is controlled by the pressure regulator (7), and the purge flow to the
shaft-seals (2) is switched on and off by the solenoid-valve (5).
The pressure transducer (6) monitors the pressure of the shaft-seals purge flow. The output of
the pressure transducer is used to display the shaft-seals purge pressure on the Pump Display
Module (if fitted).
The front panel has two pressure status LEDs (Figure 1-6, items 4 and 5). These LEDs show
whether the nitrogen supply pressure is too high, too low or is in the acceptable range: refer to
Section 5.5.
1.5
The LCMB mechanical booster pump (iL600 only)
The LCMB pump is a positive displacement Roots vacuum pump. The pump mechanism is
driven directly by a three-phase electric motor. The LCMB operates at inlet pressures of 5 mbar
(5 x 10
2
Pa) and below, and is backed by the LCDP pump. When you start the LCDP pump, the iL
system delays the start of the LCMB pump for a preset time, to allow the LCDP pump to reduce
the pressure in the process system to below the maximum inlet pressure for the LCMB pump.
1.6
Temperature control system
1.6.1
LCDP pump temperature control system
The headplate and the pump-motor/gearbox of the LCDP pump have a direct cooling system in
which water flows around these parts of the pump. All other stages of the pump are air-cooled
by natural convection and radiation.
(Continued on page 1-6)
iL Dry Pumping Systems
1-5
Figure 1-2 - Schematic diagram of the LCDP pump gas system
(sensor-configured iL systems only)
1.
LCDP pump
2.
Shaft-seals
3.
Shaft-seals purge pipeline
4.
Restrictor
5.
Solenoid-valve
6.
Pressure transducer
7.
Pressure regulator
8.
Check-valve
9.
Nitrogen supply inlet
