The system has a range of 250 psig to the
pressure capacity of the supply cylinder. When
you place the high-pressure regulator in the
LOAD position, nitrogen flows through the one-
way check valve that protects the back side of the
high-pressure regulator. This pressure is indicated
on the regulated high-pressure gage (10). It then
flows through high-pressure lines to the one-way
check valve. Pressure continues to flow to the inlet
pressure on/off valve and the system bleed valve.
(Ensure this valve is closed; if it is open, it bleeds
the system.) Pressure also flows to the vent
pressure valves and to a gage guard (F) that
protects the low-range and high-range leakage
rotameters. This gage guard is set to relieve
pressure at 170 ± 5 psig. The regulated low-
pressure gage indicates this pressure although it
is not part of the system. When you place the in-
let pressure on/off valve in the ON position, high-
-pressure nitrogen flows to the N2 input connection
a n d t h e t e e c o n n e c t o r l o c a t e d i n s i d e t he
c h a m b e r s . T h e N2 input pressure gage indi-
cates its gage guard setting of 145 ± 5 psig.
The regulated high-pressure gage indicates the
actual pressure at the N2 i n p u t c o n n e c t i on
and tee connector.
PRESSURIZING THE REGULATED
HIGH-PRESSURE SYSTEM
To pressurize this system, turn the high-
-pressure regulator clockwise to the LOAD posi-
tion until you have the desired pressure. It will
be indicated on the high-pressure gage.
To check the regulated high-pressure system
for leaks, you must first cap the N2 i n p u t
connection located inside the chamber. Now open
the supply cylinder and load the system to 2000
psig using the high-pressure regulator. This is
indicated on the high-pressure gage. You should
also have a reading of 170 ± 5 psig on the
regulated low-pressure gage. This is the setting of
your gage guard for the protection of the low-
range and high-range leakage rotameters.
Close the supply cylinder and note the pressure
on the high-pressure gage. After 2 minutes, reread
the pressure. If your system is in good working
condition, no drop in pressure should occur.
With the inlet pressure on/off valve closed,
you should have no reading on the N2 i n l et
pressure gage. If a pressure is registered, it
indicates that you have a leak within one or both
of your on/off valves (N2 inlet or leakage).
Figure 2-4.—Model 1172AS100 regulated high pressure N2 system.
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