tbe
erent’
B.7.2
A calibration panel built at BRL was designed to be a complete
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\
Calibration Equipment
field unit in itself, only a 110 V A.C. power source being required
i
for field operation of the panel.
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ew
An aircraft high-pressure air com-
pressor and reservoir and a vacuum pump were part of the calibrator,
2se and a 28 V selenium power rectifier were mounted on a collapsible
\Btand and connectedto the calibration panel.
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Flexibility, ease of operation, and safety were prime considera| \tfons_ in the design of the panel.
Use of numerous pressure elements
4 “Sh
the various shots of the test series made easy operation important.
Solenoid valves and a simplified control system were incorporated.
Reghiators allowed a quick setting of pressure steps.
The interlocking
relay|psystem and locations of operating switches and buttons promoted
the-safety required by the high pressures sometimes used in the cali-
brator.
‘The pneumatic system was built very tight for accuracy in the
application of the pressure steps. A front view of the calibration
panel is‘shown in Figure C.15.
Three large, precision gages (20, 100, 500 psi ranges) were
used in setting/the pressure between 2-500 psi during calibrations.
The 20 psi Stanek was a differential-pressure gage and was utilized
for all vacuun measurements.
A water manometer was used in conjunction
with the calibr ation panel for the setting of very low pressures.
B.7.3
Special carsvkdetons
Because some Chorange elements were overstressed in Shot l,
overstressing calibrationg were run on a group of elements of each of
these ranges.
The elements=guffered a slight permanent deformation,
Too high an overpressure
diaphragm and then ruptur
cause considerable bulging in the
the diaphragm seal.
A slight deformation was
element could be recalibrated toj
Fdund to be beneficial; then the
the higher pressure without further
deforming the element,
jcalibration-after-overstressing
While thp
curve was never a straight line
en in the low-pressure region, it
was a smooth curve all the way to the pv. stressing pressure.
This
overstressing technique extended the r
e of many of the higher rated
elements used in subsequent shots of shetest series.
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