YZ Systems, Inc. • 3101 Pollok Drive • Conroe, Texas • USA • 77303 • P: 936.788.5593 • F: 936.788.5720
Page 66
NJEX 8300 ver .092001 ATEX Rev.
SSSSS
ECTION
ECTION
ECTION
ECTION
ECTION
10:
10:
10:
10:
10: M
M
M
M
M
ECHANICAL
ECHANICAL
ECHANICAL
ECHANICAL
ECHANICAL
S
S
S
S
S
Y
YY
Y
YSTEM
STEM
STEM
STEM
STEM
Solenoid Valve & Pneumatic
Relay Manifold
Two low power solenoid valves are mounted on this
manifold,
figure 178
. The solenoid valve,
SV2
located on
the left, actuates the fill valve, while the other solenoid
valve,
SV1
located on the right, pilots the pump pneu-
matic relay valve.
One pneumatic relay valve is also mounted on this mani-
fold. It is located just below the solenoid valves and serves
to actuate the pump when it receives a pneumatic signal
from the pilot relay discusses in the previous paragraph.
Supply and exhaust ports are located on the outside of
the manifold to permit operator connections on the back
of the system enclosure.
Additionally, there are three control valves located on
this manifold,
V4
lower right with a gold knob,
V5
upper
center with a green knob, and
V16
lower left with a black
knob. Valve
V4
is normally closed, but is opened to
charge the expansion tank with gas as required during
system start up or purge process. Additionally, valve
V5
is normally closed, but is opened to vent the gas from
the expansion tank for maintenance. Finally,
V16
is
normally open, and is the supply gas isolation valve.
Expansion Tank
The expansion tank,
figure 179,
is mounted on the back of
the enclosure and acts as a pressure source and buffer for
the Verometer. As the Verometer is filled or emptied, blanket
gas flows into or out of the expansion tank as required.
Because of the relatively large difference in the volumes of
the Verometer and the expansion tank, the fluctuation in
operating pressure within this system is minimal.
Mounted on the expansion tank are: a relief valve,
preset to 85 psi
(5.86 Bar);
a pressure gauge, a vent
valve; and an expansion tank isolation valve. The
connection on the bottom of the tank, valve
V14
, is used
to connect the expansion tank to the bypass loop.
Valve
V14
is normally closed, but can be opened as an
optional step in the forward purge process to purge any
liquid from the expansion tank that may have accumu-
lated, and place it back into the bulk storage tank.
Figure 178
Figure 179
Expansion Tank