Flowserve 51 Series - Manual (Page 2)

6. Media which can solidify, crystallize or polymerize should not be
allowed to stand in ball valve cavities.
7. Torque Requirements: Operating torque requirements will vary
depending on the length of time between cycles, line pressure,
type of valve seats and the media in the system. For a detailed
analysis of valve torque requirements, see Worcester’s Actuator
Sizing Manual.
NOTE: Media which contain fine powders (25 microns or less)
will significantly raise ball valve torque requirements.
CAUTION
8. The fluoropolymer (T) and UHMWPE (U) body seals, the graphite
body seals (Z) and the seat back seals (used with “A” or “G”
seated (filled metal) valves) make excellent seals. However, some
points of caution in their use need emphasizing.
a. No seat back seal, graphite body seal, fluoropolymer or
UHMWPE part (except a seat) is reusable. Upon disassembly of
the valve, they should be discarded and replaced with new
parts.
b. Care must be taken to avoid scratching the fluoropolymer or
UHMWPE seal during installation. Light lubrication of these
seals can help to prevent damage. Care must also be taken
when handling a graphite thrust bearing, stem seal, body seal
or seat back seal. These parts are easily damaged and should
be handled on the flat surface rather than the O.D.
c. The ball used in “A” or “G” (filled metal) seated valves has a
special anti-galling coating. DO NOT use an uncoated ball with
filled metal seats. To ensure proper contact with the seat, do
not drop, dent or scratch the ball during handling.
C. MAINTENANCE
If seepage is noted at stem, tighten retaining nut 1 /
6
turn at a time until
seepage stops.
CAUTIONS: Excessive tightening causes higher torque and shorter
stem seal life.
For chlorine valves only, immediately after the first frost is
detected around the stem, tighten the retaining nut to adjust the
compression of the stem seals.
D. REBUILDING
a WARNING: BALL VALVES CAN TRAP PRESSURIZED FLUIDS IN
BALL CAVITY WHEN CLOSED.
If the valve has been used to control hazardous media, it must be
decontaminated before disassembly. It is recommended that the
following steps are taken for safe removal and disassembly:
- Relieve the line pressure. Operate the valve prior to attempting
removal from line.
- Place valve in half-open position and flush the line to remove any
hazardous material from valve body.
- All persons involved in the removal and disassembly of the valve
should wear the proper protective clothing such as face shield,
gloves, apron, etc.
- For chlorine valves, refer to Chlorine Institute Pamphlet #6 for
flushing and drying procedure, and for additional information or
precautions and cleaning.
1. A standard repair kit may be ordered for the valve. Specify the
size, series, material of seats and body seal and R# (revision
number) of valve or for non-standard valve, the “P” number, “T”
number, “C” Number, or similar number, as found on nameplate.
Some series, such as CL, PT, FZ, AF, and V51 option have their
own repair kits, which are ordered by the prefix or adding V51
suffix. If valve body is stainless steel, place a “6” after the valve
size in repair kit ordering code.
Examples:
P, T, C
or
Valve Prefix similar
Size (if required) RK Series Material Rev. # #
3” AF RK 51 PT R3 —
3” RK 51 RT R5 V51 —
4” RK 51 T — T0914
NOTES: For Series 4 (151/301) and 52 valves, repair kits can be
ordered as RK51. V51 high-cycle stem packing option cannot be
used with CL, FZ, AF series, or oxygen service valves or valves
with “G” seats.
CAUTION: If the seats and seals installed differ from those
removed, the valve nameplate must be replaced or remarked to
indicate the altered materials and ratings or valve tagged to so
indicate.
2. This covers rebuilding of both flanged and wafer valves.
Special handling and cleaning procedures are necessary for
oxygen and vacuum service valves. Refer to industry practices
when overhauling these units.
NOTE: Series 51 and 52 Revision OF valves do not have retaining
screws. Consult your distributor or Flowserve for end plug
removal tools to facilitate removal of screwed ring insert retainer.
a. Disassembly of Valve:
1) Place valve in open position. Unscrew all flange bolts or
studs and nuts and remove valve from line.
2 12230-N
Flow Control Division
Worcester Controls