The vacuum gauges HyVac offers fall
into 3 basic groups.
Bourdon Tube Gauge - Mechanical - Medium Vacuum -
Mechanical - Medium Vacuum
/ 0-760mm also available
0-30" bourdon tube vacuum gauges are okay for very
rudimentary vacuum pressures below 28" of mercury vacuum. They are not really very
good, due to inaccuracies based on things such as the barometric pressure of the day, or
the users height above or below sea level just to name a few. Adjustments to scale reading
must be calculated to accurately determine what number you are actually reading today. If
the end user is looking for a reading of 20-29" of Hg vacuum, these bourdon
tube gauges 0-30" are the gauges for them. .
- Physical - Medium Vacuum
Primary standard via NIST, but again allowances have to be made,
but generally more accurate than the 0-30" gauges mentioned above and carry the backing
of being a primary standard means no calibration on a continuing basis is required, once
certification is accomplished. They also though, require calculation based on
atmospheric conditions and geographic location of the end user to determine true readings. They are
scaled from 0-30" or 0-760mm. The most common employ mercury as the indicator
although oil as a medium is also available.
Types of Manometers.
High VacuumT/C or
Thermocouple Gauges - High Vacuum -
to 10-4 Torr or .0001mm Hg vacuum.
These are electronic gauges employing a thermocouple gage sensor
head of varying degrees of sensitivity and a meter of some kind that will reflect the
appropriate scale. HyVac has 3 main types of gauges in this category. All basically
measure the pressure from either 2-5 Torr down to 5 microns of mercury vacuum. They have
some limitations, but basically, a good, general purpose, portable, high vacuum gauge. The
viewing scales available are analog (like a VU meter), digital with direct digital read
out of microns or LED type where a bar graph shows what pressure you have achieved. All
three are a great choice for vacuum readings from 2 Torr down to 20 microns. This is the
type of gauge to consider, with options, if unattended computer data logging is a
requirement or desire.
- Physical - High Vacuum
HyVac makes and markets a McLeod gauge. We use these gauges to
test our pumps during the manufacturing process. They are very accurate for pressures
between 50-.1 microns of Hg vacuum. The HyVac gauge is based on a compound system
employing mercury and special oil which gives the gauge the accuracy of a mercury gauge
with the responsiveness and sensitivity of an oil gauge. Fast degassing times and fast
repeatability are the trademarks of this gauge. The mercury in the gauge is covered with
oil and never gets exposed to working atmosphere so minimizes any work place environmental
concerns typical of mercury based gauges without sacrificing performance. McLeod gauges
again are a primary standard subscribing to Boyle's/Charles Law of gas compressibility so
calibration is accomplished only once. Certification for this gauge is available and a NIST traceable calibration service when required is also available.
HyVac Specifications McLeod Gauge
HyVac McLeod Gauge
Set-up and Hints
Pressure Range McLeod Gauges Mercury Based
If your aim is to measure
pressures below .1 micron we can help you out here also but the gauges start to get exotic
more specialized and more expensive.
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