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Figure 12. Type EZHSO DN 100/150/200 (Spring-to-Open Version) Operational Schematic
V
R
M
R2
Inlet pressure (P
)
INLET PRESSURE (Pu)
u
Motorization pressure (P
MOTORIZATION PRESSURE (Pm)
Pilot feeding pressure (P
PILOT FEEDING PRESSURE (Pup)
Outlet pressure (P
)
OUTLET PRESSURE (Pd)
d
Atmospheric pressure (P
ATMOSPHERIC PRESSURE (Pb)
When the gas demand in the downstream system has
been satisfied, the outlet pressure increases. When outlet
pressure increases over the setting of the pilot spring,
the pilot valve plug will be closed reducing motorization
pressure to the actuator diaphragm; the pressure in the
upper case will force the regulator to close. The excess
motorization pressure acting under the regulator actuator
diaphragm and pilot bleeds to the downstream system
through a bleed restriction in the pilot.
For Type EZHSO DN 100, 150 and 200 a check valve
(Figure 28) is installed between outlet pressure and loading
pressure impulse lines; this valve is designed to protect the
main valve diaphragm assembly from wrong procedures
during startup, avoiding a too high pressure differential
between outlet and motorization pressure.
EZH and EZHSO Series Adjustment
The adjustment of the regulator is performed by means
of the pilot adjusting screw, which causes variation of the
compression of the control spring.
Adjustment is performed while the regulator is in operation
with the aid of a pressure gauge to monitor downstream
pressure.
S
B
L
A
)
m
)
up
Type PRX:
S - Bleed port
)
B - Supply port
b
Types EZH and EZHSO
Type SA/2:
V - Sensing
L - Motorization port
R - Pilot
A - Sensing port
M - Inlet
The shut-off valve downstream of the regulator must not be
completely closed, it is necessary that a small quantity of
gas flows downstream to allow the outlet side to vent when
it is necessary to lower the pressure.
Loosen the Type PRX pilot locknut and turn the adjusting
screw slowly clockwise to increase outlet pressure and
counterclockwise to decrease outlet pressure. Use a
pressure gauge to monitor the outlet pressure until the
desired pressure is reached. No adjustment is needed to
the Type SA/2 stabilizer filter.
R3
R4
RP
IP
11
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