MKS Granville-Phillips Mini-Convectron 275 series, Инструкция по эксплуатации

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Chapter 4
42
Mini-Convectron Module with RS-485
Instruction Manual - 275545
Example 1: Maximum Safe Indicated Pressure
Assume a certain system will withstand an internal pressure of 2000 Torr or
38.7 psia. For safety, limit the maximum internal pressure to 760 Torr
during backfilling. Assume you want to measure the pressure of argon. On
Figure 4-2 locate 760 Torr on the left hand scale, travel to the right to the
intersection with the argon (Ar) curve and then down to an indicated
pressure of 24 Torr (N
2
equivalent). Thus in this hypothetical situation the
maximum safe indicated pressure for argon is 24 Torr.
For safety, place a warning label on the instrument which under the
assumed conditions would read "DO NOT EXCEED 24 TORR FOR
ARGON."
Example 2: Indicated to True Pressure Conversion
Assume you want to determine the true pressure of argon in a system when
the Convectron is indicating 10 Torr. On Figure 4-2, read up from 10 Torr
(N
2
equivalent) indicated pressure to the argon curve and then horizontally
to the left to a true pressure of 250 Torr. Thus 250 Torr argon pressure
produces an indication of 10 Torr (N
2
equivalent).
Example 3: True to Indicated Pressure Conversion
Assume you want to set a process control setpoint at a true pressure of
20 Torr of C0
2
. On Figure 4-2, locate 20 Torr on the true pressure scale,
travel horizontally to the right to the C0
2
curve and then down to an
indicated pressure of 6 Torr (N
2
equivalent). Thus the correct process
control setting for 20 Torr of C0
2
is 6 Torr (N
2
equivalent).
Example 4: True to Indicated Pressure Conversion
Assume you want to obtain a helium pressure of 100 Torr in the system. On
Figure 4-3, locate 100 Torr on the left hand scale, travel horizontally to the
right to attempt to intersect the He curve. Because the intersection is off
scale it is apparent that this true pressure measurement requirement for
helium exceeds the capability of the instrument.
For gases other than those listed, the user must provide accurate conversion
data for safe operation. The Mini-Convectron gauge is not intended for use
above 1000 Torr true pressure.