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Principles of Operation
During normal operation in the untripped condition, the plug is
retracted into the fully open position. The downstream pressure
is monitored by the Overpressure and/or Underpressure sensing
diaphragms. If an overpressure or underpressure condition
occurs, the sensing diaphragms will move the trip shaft, causing
the valve to trip completely closed. After the Slam Shut has
tripped, the valve must be reset manually.
Hydrostatic Testing
All Slam Shut stand alone valves and Slam Shut valves integrated
into Flowgrid valves are hydrostatically tested at the factory prior
to shipment according to ISA-S75.19-1989 and MSS-SP-61
standards.
If it is necessary to retest the valve, the Slam Shut valve may
be hydrotested without any modifications. If a Flowgrid regulator
is integrated into the Slam Shut, care should be taken to not
damage the diaphragm. Refer to the Flowgrid IOM GEA19583.
Installation
Personal injury, equipment damage, or leakage
due to explosion of accumulated gas or bursting of
pressure containing parts, may result if the Slam
Shut is over pressured, or is installed where service
conditions could exceed the limits given in the
specication of this manual, or on the nameplate, or
where conditions exceed any ratings of the adjacent
piping or piping connections. Verify the limitations
of the Flowgrid regulator, Slam Shut valve and pilot
to ensure none of the devices are over pressured.
To avoid such injury or damage, provide pressure
relieving or pressure limiting devices as required by
applicable codes to prevent service conditions from
exceeding those limits. Additionally, physical dam-
age to the regulator could result in damage such as
breaking the pilot (if supplied) off the main valve,
causing personal injury and/or property damage due
to explosion of accumulated gas.
To avoid such injury and damage, install the Slam
Shut and regulator in a safe location.
Note: The Slam Shut maybe supplied as a stand
alone unit or integrated into a Flowgrid regulator
with lters, restrictors and pilots. This procedure
covers the installation of the Slam Shut and may
refer to components not ordered with the Slam Shut.
Consult the proper IOM for the installation of Flow-
grid regulator, lters, restrictors and pilots.
1. Personnel: Installation of the Slam Shut valve and/or
Flowgrid regulator should be made by qualified personnel
familiar with high pressure piping and pilot operated
regulators.
2. Prior Inspection: Inspect the Slam Shut valve, regulator,
pilot, and tubing for any damage that might have occurred in
shipping. Make sure the body, pilot lines, and inlet piping are
clear and free from foreign material.
3. Orientation: Stand alone Slam Shuts must be installed
up stream of the pressure regulator to provide secondary
protection. The Slam Shut valve or Slam Shut integrated
into a Flowgrid regulator may be installed in any position,
the best position being one that provides easiest access for
the Slam Shut, pilot adjustment and maintenance.
4. Screwed End Valves: Apply pipe compound to the male
threads starting one or two threads back from the end prior
to assembling the joint.
5. Flanged End Valves: Use suitable line gaskets and standard
bolting practices with flanged bodies. A criss-cross pattern
of incrementally tightening the line bolts is recommended.
6. Weld End Bodies: Before welding a butt weld and/or a socket
weld valve body, disassemble the valve. On stand alone
Slam Shuts remove the bonnet, Slam Shut body assembly
and all O-rings. On Slam Shuts integrated into Flowgrid
valves; remove the Slam Shut body assembly, Spring
Case and all trim parts including diaphragm and O-rings.
Reassemble the valve (refer to the MAINTENANCE section
of this manual for Disassembly and Assembly procedures)
and pressurize to check for leaks prior to putting the valve in
service.
7. Slam Shut Sense Line: Install a 3/8 inch OD tube from
the sense port to a port on the pipe line located 8 to 10
pipe diameters minimum of straight pipe downstream of
the final regulator in the run. The sense port is located on
the downstream side of the controller and latch module just
above the Slam Shut label.
Note: The sense line connection should be away from
areas of turbulence (such as valves, reducers, and
elbows) and should have a full opening into the pipe free
from burrs, drill peels, and weld slag. Shutoff valves are
not required in the control line(s), but if installed, they
should be of the full opening type.
8. Inlet Pressure Lines: All pilots or other devices requiring
a supply of inlet pressure that can result in a flow of gas
downstream of the Slam Shut must be connected to the
center port (port inlet) on the Slam Shut body assembly. A
shut off valve may be installed in the sense line to prevent
the Slam Shut valve from closing during setup of regulators
and other equipment and to aid in setting up the Slam Shut
valve.
