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Appendix F
THE VERY LOW PRESSURE (VLP) GAGE
F.1
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'
INTRODUCTION
~The very low pressure (VLP) gages used in Operation CASTLE were
désigned and constructed at BRL.
i¥équire a minimum of maintenance,
They are simple in operation and
The stations for this operation were
“attended by one technician although they canbe modified to start at
zero ‘time by the use of a photo-cell initiation circuit.
The gage is
self-contained and self-recording and is capable of measuring pressure
differentials in the 0 to 0.500 psi range with a sensitivity of 0.001
psi. i ok
¥.2 DESCRIPTION
The VLP gage itself consists of four major parts:
1.
A pressu é. sensing diaphragm which consists of a single phos-
phor-bronze convglutdd diaphregn, 5-3/4 inches in diameter, having a
stylus arm with &sapphire tipped needle soldered to the center to
transmit its motion toythe recording dise.
2.
Los
The recording“diisc is a five-inch diameter glass disc, 1/16
inch thick, with an alubipicea coating.
A trace of less than one mil
wide and approximately 4-3/4 (fhches in dtameter is recorded.
The width
of the trace will vary with i quality of the coating and stylii point.
3.
The drive motor wad
spring driven chart drive type with a
recording speed of one revolution per-four hours.
The turntable which
held the recording disc was mounted directly to the drive shaft of the
motor.
.
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4,
The gage case is a steel box eight inches
and seven inches deep with a removable edver on the
gasket was used to seal the lucite cover making the
Two views of the gage are shown in Figures) C.13 and
potenama
F.3
square on the front
top.
<A ruboer
gage air tight.
C.14,
CALTBRATION
The gages were not completed soon enough tovallow an accurate
calibration before being shipped to the field. They were however
calibrated soon after their return to the laboratory.! [Usiing a small
valve on the side of the gage, a vacuum system was used /to calibrate
this type VLP gage.
peaarly
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