10
Figure 11. Type EZHSO DN 25/50/80 (Spring-to-Open Version) Operational Schematic
FILTER
V
M
R
S
B
L
A
R2
R3
R4
TYPE
SA/2
TYPE
PRX/120
TYPE EZHSO
UPPER DIAPHRAGM
LOWER DIAPHRAGM
REGULATOR
DIAPHRAGM
PILOT DISK
impulse lines; this valve will protect the 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.
The shut-off valve downstream of the regulator must not
be completely closed, it is necessary that a small quantity
of gas ows 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 lter.
case of Type EZHSO actuator is lled with pressure
coming from pre-regulator Type SA/2, which reduces inlet
pressure (Pu) to the constant value of outlet pressure
plus approximately 3 bar. This pressure opposes the
main spring force that tends to open the regulator.
Outlet or downstream pressure (Pd) opposes the pilot
control spring. When outlet pressure drops below the
setting of the pilot control spring, pilot control spring
force on the pilot diaphragm opens the pilot valve plug,
providing additional motorization pressure (Pm) to the
actuator diaphragm.
This diaphragm motorization pressure opens the main
valve plug, supplying the required ow to the downstream
system. Any excess motorization pressure on the actuator
diaphragm escapes downstream through the bleed
restriction in the pilot.
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.
For Type EZHSO DN 100 a check valve (Figure 26) is
installed between outlet pressure and loading pressure
S - BLEED PORT TYPE SA/2
B - SUPPLY PORT V - SENSING
L - MOTORIZATION PORT R - PILOT
A - SENSING PORT M - INLET
INLET PRESSURE (Pu)
OUTLET PRESSURE (Pd)
MOTORIZATION PRESSURE (Pm)
PILOT FEEDING PRESSURE (Pup)
ATMOSPHERIC PRESSURE (Pb)
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