Types 98LD and 98HD
5
pipeline. The relief valve regulator should
be inspected for damage regularly and
after any overpressure condition. .
Overpressure Protection
!
WARNING
Overpressuring any portion of this
equipment may result in equipment
damage, leaks in the relief valve,
or personal injury due to bursting
system should be inspected after any
overpressure condition.
Relief pressure ranges are from 2 to 200 psig
(0,14 to 13,8 bar). The individual spring range of your
relief valve is stamped on the nameplate. Maximum
inlet pressures depend upon body materials and
temperatures. See Specications for the maximum inlet
pressures and maximum spring case loading pressures
for Types 98LD and 98HD relief valves.
Relief Valve Outlet
!
WARNING
If using a Type 98LD or 98HD Relief Valves
personal injury and property damage
vented gas that may have accumulated.
To prevent such injury or damage, provide
piping or tubing to vent the gas to a safe,
a hazardous gas, the piping or tubing
should be located far enough away from
any buildings or windows so not to create
a further hazard, and the vent opening
should be protected against anything that
could clog it. .
If remote venting is necessary, install a remote vent
line in the outlet connection of the relief valve. The
vent line must have the largest practical diameter and
be as short as possible with a minimum number of
bends or elbows.
Startup
Note
Table 1 show the maximum inlet and
constructions. Use pressure gauges
to monitor inlet pressure, outlet
pressure, and any intermediate
pressure during startup.
With proper installation completed and system
equipment properly adjusted, close any block and vent
valves, and back out the adjusting screw by turning it
counterclockwise (or by turning the handwheel in the
same manner).
Slowly open the following valves in this order: loading
supply and control line, inlet block valve and outlet
block valve.
Set pressure is adjusted by following the Adjustment
procedure.
Adjustment
Each unit is factory set for the pressure setting
specied on the order. The allowable spring range
is stamped on the nameplate. If a pressure setting
beyond the indicated range is required, substitute the
appropriate spring. Be sure to label the relief valve to
indicate the new pressure range.
Always use a pressure gauge to monitor pressure when
making adjustments. If the differential pressure needs
to be increased, turn the handwheel (key 38, Figure 4 or
5) clockwise. Turn the handwheel counterclockwise to
decrease the differential pressure.
Shutdown
Close the upstream shutoff valve and release all
pressure from the relief valve. .
Maintenance
!
WARNING
To avoid personal injury and
equipment damage, isolate the relief
valve from all pressure. Cautiously
release pressure from the relief
valve before attempting disassembly.
.
Due to normal wear and damage that may occur from
external sources, relief valve parts such as the O-rings,
gaskets, diaphragm, orice, and valve plug should be
inspected periodically and replaced as necessary. The
frequency of inspection and replacement depends upon
the severity of service conditions or the requirements of
state and federal laws.
Instructions are given below for disassembly of the
Types 98LD and 98HD relief valves. These relief
valves do not have to be removed from the pipeline
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