The SVP Medium Accuracy Vacuum Gauge is
based on the Hastings 0-1,000 mtorr (micron)
meter assembly. SVP has chosen Hastings
instruments for their quality and dependability
when used in close proximity to high voltage.
Hastings instruments are legendary for their
reliability and accuracy. They are the standard
by which other vacuum gauge manufacturers
compare their products to, many of who use
Hastings components for their own gauges – a
testament to the quality of Hastings products.
A high vacuum gauge is used to measure the ultimate vacuum
obtained within the manifold following the processing procedure
and prior to backfilling the tube with inert gas. This
instrument ensures that the tube was adequately evacuated. A
high vacuum gauge is also valuable in determining the integrity
of the vacuum system, as well as troubleshooting problems if
they arise. Once a technician has become familiar with this
instrument and how it reacts to various conditions and
situations it can also be invaluable in avoiding problems.
A vacuum gauge capable of measuring down to at least 1 micron
should be used and this level of vacuum should be strived for. A
vacuum of 1 micron is where molecular flow begins to take place
and where the high vacuum region begins. Analog vacuum gauges
are best suited for our purposes because of the high voltage
field produced by the bombarder.
When considering a vacuum gauge, one that will measure pressures
between 1 micron and 1,000 microns is suitable for general neon
tube production. One that can measure 0.1 micron should be used
for critical neon work and Cold Cathode Lamp production.
Whatever vacuum gauge is used, whether it is line voltage
operated or battery operated, a stopcock between the vacuum
gauge tube (sensor) and main manifold body must be used to
isolate the gauge tube from the main manifold. This protects the
gauge and gauge tube from possible damage due to bombarder high
voltage, spark tester frequencies and voltage, as well as the
influx of contaminants, which are a normal result of the
bombarding process and venting the manifold to atmosphere.