Emerson EZH, EZHSO Data Sheet
Process Management
TM
PRESSURE REGULATORS
Europe, Middle East, and Africa Only
Type EZH and EZHSO
EZH and EZHSO Regulators
Europe, Middle East, and Africa Only
Pressure Regulators
Type EZH and EZHSO (Spring-to-Open) regulators are accurate pilot-operated, pressure balanced, soft seated regulators.
They are designed for use in high pressure natural gas transmission/city gate stations, large capacity distribution systems, and
power plant feeds. They provide smooth, reliable operation, tight shutoff and long life.
The main benefits are as follows:
• Longlifeinsevereserviceapplications
• Highresistancetoaromaticsandparticleerosion
• Noiseattenuationmodule(optional)
• Highturndowncapacityforsystemswithlargevariationsindownstreamflowdemand
• Absolutelynobleedtoatmosphere
• Widerangeofflowcoefficientsforeachbodysize
• Bubbletightshutoff
• Accuratepressurecontrol
• Lowtemperaturestandardversion
• Integralstrength
• Easymaintenancesystem
• Spring-to-closeandspring-to-openversions
• Long life in severe service applications: The Type EZH
and EZHSO utilize a metal plug design to deect particles
and debris away from the soft-seat, which gives enhanced
resistance to particle erosion to provide a longer service life.
In addition, the Type EZH and EZHSO can be constructed with
uoroelastomer soft parts to extend service life in applications
where liquid aromatics are entrained in the gas.
• High turn down capability: The oversized diaphragm and
unique piloting system of the Type EZH and EZHSO allow for
a 100:1 turn down ratio, which will provide superior pressure
control in systems with large variations in downstream ow
demand.
• Noise attenuation module: The EZH and EZHSO offer an optional
Whisper Trim Cage which is integral to the regulator therefore
maintaining the advantages of it's compact design. The Whisper
Trim Cage is available on DN 50, 80 and 100. It allows for a noise
attenuation up to 8 dB.
110
100
90
80
70
NOISE LEVEL (dBA)
60
50
9400
EZH AND EZHSO SERIES WITH
STANDARD CAGE
EZH AND EZHSO SERIES WITH
WHISPER TRIM® CAGE
18900 28400 37500 47100 56800 66200 75700 851000
FLOW RATE (Nm3/h)
Noise Comparison Diagram
• Absolutely no bleed to atmosphere: The Type EZH
and EZHSO eliminate nuisance and wasteful bleed gas to
atmosphere by utilizing a pilot-operated control system,
which bleeds 100% of the gas to the downstream system
while the regulator is operating.
• Wide range of flows coefficients for each body size:
EZH and EZHSO offer the possibility of ow reduction ranges
according to each body size. This is achieved by simply
replacing the standard seat by a reduction seat.
The
Whisper Trim Cage
2
• Bubble tight shutoff: The Type EZH and EZHSO have a knife-
Europe, Middle East, and Africa Only
edged, metal plug and a soft seat which provides bubble
tight shutoff for use in applications where positive shutoff is
required. For example: dead-end systems.
• Accurate pressure control: The Type EZH and EZHSO use the
Type PRX and SA/2 pilot system to provide stable and accurate
downstream pressure control regardless of load changes or
inlet pressure variations.
• Easy maintenance system: A top entry design reduces
maintenance time. Trim parts can be inspected, cleaned
and replaced without removing the body from the pipeline.
An innovative system has been designed for the EZH DN
100 which allows maintenance to be carried out by a single
operator. Maintenance is carried out by simply removing the
top plug, extracting the trim assembly (12.3 kg), removing
the pad holder and then changing the pad. Easy and fast
maintenance, no special tools requirement, makes the EZH
ownership low in cost.
• Spring-to-close and spring-to-open versions: Optional
positions to choose from in case of main valve diaphragm
failure or lack of supply pressure to the pilot. See table on
page 6 for "Failure Mode Analysis".
EZH and EZHSO Regulators
Plug
Trim assembly
Pad holder
EZH DN 100 Patent Pending Easy Maintenance System
Configurations
Type EZH: Pilot-operated pressure reducing regulator for low to high outlet pressure.
Type EZH-OS2: Type EZH pressure reducing regulator with an OS2 slam-shut device for overpressure or overpressure and
underpressure protection.
Type EZHSO: Spring-to-Open pilot-operated pressure reducing regulator for low to high outlet pressure.
Type EZHSO-OS2: Type EZHSO pressure reducing regulator with an OS2 slam-shut device for overpressure or overpressure and
underpressure protection.
EZH EZH-OS2
3
EZH and EZHSO Regulators
Europe, Middle East, and Africa Only
Operation
PRX/120
PRX/120-AP
SA/2
V
R
M
B
S
L
A
V
SA/2
M
R
PRX/120
PRX/120-AP
S
L
B
A
EZH Regulator
Inlet pressure Regulator motorization pressure
Outlet pressure Stabilized pressure
EZHSO Regulator
The pilot-operated type EZH uses inlet pressure as the operating medium, which is reduced through pilot operation to load the
actuator diaphragm. Outlet pressure (Pd) opposes the motorization pressure (Pm) in the actuator and also opposes the pilot control
spring. Type EZHSO Spring-to-Open version 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 filled with pressure coming from stabilizer
filter Type SA/2. This pressure on the upper chamber of the regulator actuator diaphragm opposes the main spring force that tends
to open the regulator. The outlet pressure opposes the pilot control spring.
For the start-up of Type EZHSO, it’s necessary to install a
vent valve in type PRX pilot bleed line connection (line from port S to downstream pipe) in order to vent the pressure from actuator lower
chamber to close the regulator.
Opening
When the outlet pressure (Pd) drops below the setting of the pilot control spring, pilot control spring force on the pilot diaphragm
thus 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 flow to the downstream system. Any excess motorization
pressure on the actuator diaphragm escapes downstream through the bleed restriction in the pilot.
Closing
EZH -
When the gas demand in the downstream system has been satisfied, the outlet pressure (Pd) increases. The increased pressure
is transmitted through the downstream control line and acts on the pilot diaphragm. This pressure exceeds the pilot spring setting and
moves the diaphragm, closing the orifice. The motorization pressure (Pm) acting on the main diaphragm bleeds to the downstream
system through a bleed restriction in the pilot.
EZHSO - When the outlet pressure (Pd) increase over the setting of the pilot spring, the pilot valve disk will be closed, reducing motorization
pressure (Pm) to the lower chamber of the regulator actuator diaphragm; the pressure in the upper chamber will force the regulator to close.
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
flows downstream to allow the outlet side to vent when it is necessary to lower the pressure.
4
EZH and EZHSO Regulators
Europe, Middle East, and Africa Only
Operation
Monitoring System
Monitoring regulation is overpressure protection by containment, therefore, there is no relief valve to vent to the atmosphere.
When the working regulator fails to control the pressure, a monitor regulator installed in series, which has been sensing the
downstream and control pressure, goes into operation to maintain the downstream pressure at a slightly higher level than normal
pressure.
During an overpressure situation, the monitoring system keeps the customer on line.
Wide-Open Monitoring Systems
SA/2
V
R
M
SA/2
V
PRX/120
PRX/120-AP
S
PRX/120
PRX/120-AP
S
R
M
EZH Monitor EZHSO Regulator
Inlet pressure
Monitor motorization pressure
B
L
A
Regulator motorization pressure
Outlet pressure
B
Stabilized pressure
L
A
This figure shows an upstream wide open monitor Type EZH and a downstream active regulator Type EZHSO (Spring-to-Open).
In this installation, if the Type EZHSO no longer controls the outlet pressure, it will remain open, letting the Type EZH regulator to
reach the required outlet pressure.
In case of failure of the Type EZH, it will close and protect the downstream system from overpressure condition.
5
Loading...