Types EZH and EZHSO
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
Inlet pressure (Pu)
Outlet pressure (Pd)
Motorization pressure (Pm)
Pilot feeding pressure (Pup)
Atmospheric pressure (Pb)
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.
Type EZHSO uses inlet pressure as the operating medium,
which is reduced through pilot operation to load the
actuator diaphragm (lower chamber). The upper 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
TYPE PRX:
S - BLEED PORT TYPE SA/2
B - SUPPLY PORT V - SENSING
L - MOTORIZATION PORT R - PILOT
A - SENSING PORT M - INLET
(20 strony)
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