Flowserve Cryogenic Ball Valves - Manual (Page 2)

2 08164-S
Flow Control Division
Worcester Controls
c. “S” type gaskets are installed with their widest flange to
the valve body (See view A on page 6).
d. Swing center section back in line.
e. Tighten and torque body bolts evenly, alternating in a
criss-cross diagonal pattern. Use torque figures below:
Bolt Diameter in-lb ft-lb
1 /
4
" 72-94 6-8
5 /
16
" 120-144 10-12
3 /
8
" 192-216 16-18
7 /
16
" 336-384 28-32
1 /
2
" 504-552 42-46
D. When installing the 3"–6" Worcester Cryogenic Valves, use
standard gaskets which are suitable for the specific service.
Tighten the flange bolts or studs evenly and in proper tightening
sequence.
E. Please note: on the 3"–6" flangeless short pattern valves
(151 or 301), the ball protrudes slightly from each port. After
determining the proper valve position (i.e., relief hole in ball
from section I.A), open the ball before installation to avoid
damaging it.
II. OPERATION
A. To operate the Worcester Cryogenic Ball Valve, turn the stem
1 /
4
-turn clockwise to close and 1 /
4
-turn counter-clockwise to open.
On manually operated 1 /
4
"–2" valves, the handle acts as a pointer.
When it points across the pipeline, the valve is closed.
On manually operated 3"–6" valves, the stop plate acts as a
pointer. When it points across the pipeline, the valve is closed.
B. To operate the Worcester Cryogenic Diverter Valve, rotate handle
1 /
4
-turn to divert the flow from the bottom port to either of the side
ports. (The diverter valve also comes with a special 180° ball and
stop plate. In this case the handle would be rotated
1 /
2
-turn and
the handle would point to the port to which flow was diverted.)
C. These valves will provide positive shut-off when used in
accordance with Worcester’s Cryogenic Valve
pressure/temperature chart.
D. DO NOT leave the ball partly open. DO NOT throttle with
Worcester’s Cryogenic Valves. It will result in seat breakage.
E. DO NOT allow media which can solidify, crystallize or polymerize
to stand in the valve cavity.
F. Torque Requirements:
The valve torque will vary depending on the length of the time
between cycles, line pressure, type of valve seats, and the media
in the system.
All figures in the following table are based on laboratory tests
with LN2 as the media. These figures should approximate the
actual valve torques. For a more detailed analysis of valve torque
requirements, see Worcester’s Actuator Sizing Manual.
Maximum Expected Maximum Expected
Valve Size Breakaway Torque Valve Size Breakaway Torque
1 /
4
"– 1 /
2
" 80 in-lb 2" 625 in-lb
3 /
4
" 150 in-lb 3" 1100 in-lb
1" 200 in-lb 4" 1500 in-lb
1 1 /
2
" 475 in-lb 6" 2200 in-lb
III. MAINTENANCE
The Worcester Cryogenic Valve with the extended bonnet normally
operates with the bonnet at a higher temperature than the valve.
Because of this, there will be a frost line about two-thirds of the way
up the extension. If the bonnet becomes covered with frost, it’s an
indication that the stem seals are leaking.
Whether the valve has an extended bonnet or not, if stem leakage is
noted, then adjust the stem nut per the following procedure:
A. Stem Seal Readjustment Procedure:
CAUTION: Excessive tightening causes higher torque and
shorter stem seal life.
1. Allow the valve to warm to ambient temperature.
2. 1 /
4
"–2" Valves with Two Stem Nuts and Lockwasher:
a. On manual valves, loosen the handle nut or handle
assembly bolt (as applicable) to allow easy access to the
stem seal retaining nut. On actuated valves, loosen top
nut.
b. While holding the stem to prevent turning, tighten the
stem seal retaining nut until Belleville washers are flat
(the nut will bottom); then back off
1 /
6
turn.
c. Retighten the handle nut or handle cap screw (as
applicable) while making certain that the stem seal
retaining nut and stem are immobile.
3. 1 /
4
"–2" Valves with Self-Locking Stem Nut and Four Belleville
Washers:
a. Tighten self-locking stem nut until Belleville washers are
flat (the nut will bottom); then back off 1 /
3
turn.