Flowserve PlugSeal - Manual (Page 8)

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SECTION III.
INSTALLATION INSTRUCTION – FLANGED AND WELDED PLUGSEAL
VALVES
FLANGED:
Installation of Flowserve flanged valves is best
accomplished by locating valves in pipeline flanges,
assuring all corrosion and foreign materials are removed
from pipe flange and then center gaskets with the valve
flanges. Fasteners or taper pins should be use to align
holes and locate gaskets. Fasteners should be
tightened to the corresponding valve and fastener size.
WELDED:
Flowserve Corporation, Flow Control Division
recommends using only qualified welding procedures
and personnel for weld installation of Plugseal valves.
The following precautions should be observed:
1. The valve should be inspected prior to welding
to assure that no foreign materials obstruct the
flow passageway and that the weld preparation
area is free of corrosion and physical damage.
2. The valve plug can be removed during welding
procedure to ensure the plug and diaphragm do
not permanently deform at elevated
temperature.
Table 3
TEMPERATURE LIMITATIONS
Material Description Maximum Service
Temperature
PFA 500°F (260°C)
3. The valve plug and diaphragm must not exceed
these temperatures during welding. This
includes preheats, interpasses or post weld heat
treatments, as applicable. Refer to Figure 1 for
locations of the plug and diaphragm in the
center valve section.
4. The temperature of the center or bowl area of
the valve must not exceed the listed temperature
of the material. Valves, two inch and smaller,
must be wrapped with water soaked fire-
resistant material to cool the valve bowl inlet
where the weld is to be made. Use temperature
melt crayons equal to the plug and diaphragm
rating to mark the body welding end and monitor
the temperature. Thermocouples may be
attached to the welding end or the body surface.
Pyrometers may be used to monitor the body
bowl temperature.
5. Welding of the PlugSeal Valve without
disassembly may be accomplished with no
damage to the plug or diaphragms. Precautions
must be taken to cool the valve bowl and
monitor temperatures. CAUTION: DO NOT
ALLOW WATER FROM THE SOAKED
WRAPPING MATERIAL TO ENTER THE
WELDMENT.