Introduction/Safety
Ionization Gauge Instruction Manual - 274026 - Rev. B
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1.4
Explosion / Implosion
Do not attach cables to glass gauge pins while the gauge is under vacuum.
Accidental bending of the pins may cause the glass to break and implode.
Cables, once installed, should be secured to the system to provide strain
relief for the gauge tube pins.
Danger of injury to personnel and damage to equipment exists on all
vacuum systems that incorporate gas sources or involve processes capable
of pressuring the system above the limits it can safely withstand.
For example, danger of explosion in a vacuum system exists during
backfilling from pressurized gas cylinders because many vacuum devices
such as glass ionization gauge tubes, glass windows, glass belljars, etc., are
not designed to be pressurized.
1.5
Overpressure
Install suitable devices that will limit the pressure from external gas sources
to the level that the vacuum system can safely withstand. In addition, install
suitable pressure relief valves or rupture disks that will release pressure at a
level considerably below that pressure which the system can safely
withstand.
Do NOT use quick-connects or other friction-type connections where
positive pressure (such as backfilling operations) will exist within the gauge
tube.
Suppliers of pressure relief valves and pressure relief disks are listed in
Thomas Register under "Valves, Relief", and "Discs, Rupture".
Confirm that these safety devices are properly installed before installing the
ion gauge. In addition, check that (1) the proper gas cylinders are installed,
(2) gas cylinder valve positions are correct on manual systems, and (3) the
automation systems and programs are correct on automated systems.
1.6
Temperature
During a degas procedure, the envelope of a gauge tube becomes much
hotter than during normal operation. Be sure that materials that are heat
sensitive are not in contact with the gauge tube. Be sure that the gauge tube
is not located where personnel might come in contact with the gauge tube
during normal operation of the system.
WARNING
Do not operate ion gauges in an explosive atmosphere or
in the presence of flammable gases or fumes.
Danger of explosion or inadvertent venting to
atmosphere exists on all vacuum systems which
incorporate gas sources or involve processes capable of
pressurizing the system above safe limits.
