Flowserve Cryogenic Ball Valves - Manual (Page 5)

08164-S 5
Flow Control Division
Worcester Controls
5. Remove the wrench assembly bolt and wrench assembly
handle (if any). Hold the stem with the handle or a wrench
to prevent it from rotating and remove the retaining nut.
Remove the stop plate, or stem spacer (actuated valves).
Remove and retain the follower.
Valves without Extension:
6. a. Push stem into body cavity.
b. Remove stem seals and thrust bearing, remove and retain
metal washer(s).
Valves with Extended Bonnet:
7. a. Push stem into body cavity.
b. Remove pin from stem.
c. Unscrew bottom tang from stem extension (right-hand
thread).
d. Remove thrust bearing, remove and retain metal washer
(if present).
e. Push stem extension out of body.
f. Remove fluoropolymer stem seals, remove and retain
metal washer.
Follow Steps 8, 9, and 10 for Both Extended and Non-Extended Valves:
8. Clean all sealing surfaces on valve, stem, end plug and ball.
9. Inspect the ball and the surfaces against which the seats and
seals are installed. They should be undamaged, clean and free
of pit marks and scratches. Light marring from the action of
the ball against the seats is normal and will not affect the
operation of the valve. Flaws which can be seen but barely
detected with finger tips are acceptable. The stem and body
surfaces that the thrust bearing and stem seal(s) contact
must be undamaged, clean and free from pit marks and
scratches.
10. The thrust bearing can be distinguished from the stem seals
by the darker color of the 25% filled fluoropolymer used in
the thrust bearing.
IMPORTANT: Lightly lubricate stem seals and thrust bearing
with a PTFE-based lubricant (such as Fluorolube S-30 or
equivalent), except for valves with V20 or V33 options, which
are assembled dry.
Valves without Extension:
11. a. Place new thrust bearing and metal washer (if one was
removed) on the stem shoulder.
b. Replace stem through valve body.
c. Place metal washer over stem into the body.
d. Place three new stem seals over stem.
e. Place follower, stop (for manual valves only) or stem
spacer (for actuated valves only) and retaining nut over
stem.
f. Replace handle assembly (manual valves only).
g. Tighten retaining nut to fully compress packing, then back
off 1 /
6
-turn. Try not to overtighten. Excessive tightening
causes higher torque and shorter stem seal life.
Valves with Extended Bonnet:
12. a. Insert stem extension into body.
b. Place new thrust bearing and metal washer (if one was
removed) onto bottom tang shoulder and insert it through
the ball cavity into the stem hole recess.
c. Screw bottom tang into the stem extension until it
bottoms out.
d. Align pin holes.
e. Insert new grooved pin until flush with the outside of the
extension.
f. Place metal washer over stem extension.
g. Place three new stem seals over extension.
h. Replace follower, stop (manual valves only) or stem
spacer (actuated valves only) and retaining nut.
i. Replace handle assembly (manual valves only).
j. Tighten retaining nut to fully compress packing, then back
off
1 /
6
-turn. Try not to overtighten. Excessive tightening
causes higher torque and shorter stem seal life.
Follow Steps 13 through 17 for Both Extended and Non-Extended
Valves:
13. Insert a new seat into body. Make sure seat rests firmly
against back surface of recess.
14. Place ball into body making sure that the relief hole in the ball
is upstream (end plug side), when valve is closed. Note arrow
stamped on the body or on the bonnet plate indicating flow
path. Rotate stem to align with ball slot. Place new body seal
into body. Make sure it rests squarely on sealing surface.
CAUTION: If the body seal is installed in the end plug, it
will be damaged.
15. Insert new second seat in cavity of end plug.
16. Assemble end plug and body, securing with end plug
retaining screws. It may be necessary to assist seating of the
end plug into valve cavity before securing with retaining
screws. Proper installation will allow no more than .010"
protrusion of the end plug beyond the valve body.
17. Rotate ball to open position. Place the valve between flanges
with gaskets and secure, making sure that relief hole in ball
will be on upstream side when in closed position. Retighten
end plug retaining screws.
18. Cycle valve several times before putting into service to assure
even distribution of cryogenic lubrication on valve seats.