Fisher 461 Instruction Manual page 10

461 Valve
June 2017
When all nuts are tightened to that torque value, increase the torque by 1/4 of the specified nominal torque and
repeat the crisscross pattern. Repeat this procedure until all nuts are tightened to the specified nominal value. Apply
the final torque value again and, if any nut still turns, tighten every nut again.
Note
When installing packing rings, prevent entrapping air between the rings. Add the rings one at a time without forcing them below
the chamfer of the packing box entrance chamber. As each successive ring is added, the stack should not be pushed down more
than the thickness of the added ring (figure 5).
15. Install new packing and the metal packing box parts according to the appropriate arrangement in figure 3. If
desired, packing parts may be pre‐lubricated with a silicon base grease for easier installation. Slip a smooth‐edged
pipe over the valve stem, and gently tamp each soft packing part into the packing box, being sure that air is not
trapped between adjacent soft parts.
16. Slide the packing follower, wiper, and packing flange into position. Lubricate the packing flange studs (key 24) and
the faces of the packing flange nuts (key 25). Replace the packing flange nuts.
For the spring‐loaded PTFE V‐ring packing shown in figure 3, tighten the packing flange nuts until the shoulder on the
packing follower (key 29) contacts the bonnet.
For graphite packing, tighten the packing flange nuts to the maximum recommended torque shown in table 2. Then,
loosen the packing flange nuts, and retighten them to the recommended minimum torque shown in table 2.
For other packing types, tighten the packing flange nuts alternately in small equal increments until one of the nuts
reaches the minimum recommended torque shown in table 3. Then, tighten the remaining flange nuts until the
packing flange is level and at a 90‐degree angle to the valve stem.
For ENVIRO‐SEAL or HIGH‐SEAL live‐loaded packing, refer to the note at the beginning of the Maintenance section.
17. Mount the actuator on the valve body assembly, and reconnect the actuator and valve plug stems according to
the procedures in the appropriate actuator instruction manual.
Table 2. Recommended Torque for Graphite Type Packing Flange Nuts (non live-loaded)
VALVE STEM DIAMETER
mm Inches
19.1
25.4
31.8 1-1/4
10
PRESSURE RATING
CL600
CL900
3/4
CL1500
CL2500
CL600
CL900
1
CL1500
CL2500
CL600
CL900
CL1500
CL2500
TORQUE
NSm
Min Max
21 31
27 41
34 50
41 61
35 53
42 62
52 77
61 91
49 74
56 83
68 102
81 122
Instruction Manual
D100714X012
lbfSft
Min Max
15 23
20 30
25 37
30 45
26 39
31 46
38 57
45 67
36 55
41 61
50 75
60 90