Design
Features
The Type DB Vacuum Reference Tube is an evacuated, sealed vacuum gauge tube
accurately calibrated to precisely simulate a gauge tube at a given operating
pressure. It is electrically equivalent to the metal and glass gauge tubes
used with Hastings Instruments. It permits quick and easy recalibration
of Hastings Vacuum Gauge Indicators by merely plugging the instrument into
the reference and adjusting the calibration “current set” potentiometer
until the instrument reads the exact pressure noted on the reference. The
Type DB Vacuum Reference Tubes are available equivalent to most Hastings
Gauge Tubes.
Application
Hastings Vacuum Gauge Indicators, Controllers, or Recorders can be checked
or recalibrated in seconds by merely plugging the gauge tube cable into
the reference tube. If calibration adjustment is necessary, the “Current
Set” potentiometer is adjusted until the instrument indicates the pressure
marked on the vacuum reference tube. The customer now knows his instrument
is correctly calibrated.
Whenever cable lengths between gauge tube and instrument are changed, some
error may be introduced, requiring that the instrument be readjusted to
compensate for any losses involved. By plugging the DB Vacuum Reference
Tube into the new cable and readjusting the instrument for a correct reading,
this “error” is eliminated.
Selection
Choose the vacuum reference tube that is equivalent to the glass or metal
Hastings Gauge Tube you are now using. The vacuum reference tube will be
matched and sealed at a pressure falling on the lower portion of the scale
and calibrated accurately at this exact pressure. For example, if an instrument
uses a DV-6M Gauge Tube, a DB-20 Reference Tube is ordered. If a customer
receives a reference tube marked “at 10 mTorr”, this is the pressure
to which the indicator should be adjusted when plugged into the vacuum reference
tube.
Construction
The Type DB Vacuum Reference Tubes employ the same Hastings noble metal
thermopile used in all Hastings Thermopile Vacuum Gauge Tubes. The thermopile
is sealed in a glass capsule that has been evacuated, baked, outgassed,
sealed, and then aged to ensure stability over long periods of time. The
sealed capsule is then housed in a protective metal shell to provide a rugged,
trouble-free assembly.
Calibration
Considerable care and time are required in the manufacture to obtain the
high degree of precision and stability required for the vacuum reference
tube.
The Type DB vacuum reference tube maintains its calibration over long periods
of time. However, for applications requiring the highest possible degree
of accuracy, a periodic return of the reference tube to the factory for
a check and recalibration may be desirable. An annual or semiannual check
assures the customer of an accurate and reliable reference at all times.
Selection
Chart
Equivalent
Gauge Tube and Range
Type
DB Vacuum Reference Tube
Series
Range
Model No.
Stock No.
DV-4
0-20 Torr
DB-16D
55-101
DV-5
0-100 mTorr
DB-18
55-103
DV-6
0-1000 mTorr
DB-20
55-104
DV-8M
0.01-10 mTorr
DB-31
55-105
DV-23
0-5000 mTorr
DB-33
55-106
DV-24
0-50 Torr
DB-44
55-107
DV-310
0-1000 mTorr and
0-1400 mbar
IMPORTANT
NOTE: These vacuum reference tubes are designed specifically for use with
instruments employing Hastings circuitry and are NOT interchangeable with
instruments using other circuitry. Connection to another manufacturers instrument
may result in burnout.
