Instruction manual

Oct 04 Issue H
GV Dry Vacuum Pumps
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INTRODUCTION
1INTRODUCTION
1.1 Scope and definitions
This manual provides installation, operation and
maintenance instructions for the BOC Edwards GV
Dry Vacuum Pumps (abbreviated to GV pump(s) or
pump(s) in the remainder of this manual). You must
use the GV pumps as specified in this manual.
Read this manual before you install and operate your
pump. Important safety information is highlighted as
WARNING and CAUTION instructions; you must
obey these instructions. The use of WARNINGS
and CAUTIONS is defined below.
The following IEC warning labels appear on the
pump:
The units used throughout this manual conform to
the SI international system of units of measurement.
Where appropriate, US equivalent units of
measurement are also given.
WARNING
Warnings are given where failure to
observe the instruction could result
in injury or death to people.
CAUTION
Cautions are given where failure to observe the
instruction could result in damage to the
equipment, associated equipment and process.
1.2 The GV pumps
Refer to Figure 1. The GV pumps are rugged,
reliable dry vacuum pumps designed for general
vacuum use.
The pump is a three-stage, positive displacement
rotary pump in which pairs of intermeshing rotors
(mounted on common shafts) are held in correct
phase relation by a pair of timing-gears. The timing-
gears and the adjacent double-row angular contact
ball bearings are oil lubricated.
The pump has lifting-bolts (5) and is mounted on a
robust frame (9). Fixing holes (8) in the frame can be
used to secure the pump frame in its operating
position.
1.3 Gas system
Refer to Figure 1. The pump has a shaft-seals purge
system and a gas-ballast system.
You can connect a dry compressed air supply to the
shaft-seals purge inlet (22). The shaft-seals purge
pipeline then delivers the dry air purge to the shaft-
seals. This dry air purge: ensures that the shaft-seals
are maintained at a positive pressure during pump
operation; prevents the entry of corrosive or toxic
process vapours into the pump gearbox; prevents
contamination of the process gases by pump oil;
prevents damage to the shaft-seals by debris.
As supplied, the gas-ballast system can deliver
ambient air to the pump gas-ballast inlet. The air-
flow is filtered and is controlled by a valve (10). A
check-valve (Figure 7, item 10) prevents the escape
of process gases out of the gas-ballast system into
the local atmosphere.
If required for your application, you can connect dry
nitrogen supplies to the pump, to deliver nitrogen
gas-ballast and nitrogen shaft-seals purge instead of
air: refer to Section 3.10.
Warning - refer to accompanying
documentation.
Warning - risk of electric shock.
Warning - hot surfaces.