Type A31A
9
Table 6. Torque Values for Fasteners
FASTENER NOMINAL SIZE
#10
1/4
5/16
3/8
7/16
1/2
9/16
5/8
3/4
7/8
1
1-1/8
Retaining
Lbf
S
in
Lbf
S
ft
Retaining
Ring
41
100
220
400
53
83
119
166
296
480
720
1000
Ring
Screws
N
S
m
4.6
11
25
45
72
112
161
225
401
651
976
1356
G
Lbf
S
in
Lbf
S
ft
Gasket
Retaining
35
81
167
295
39
59
86
119
210
330
480
617
Retaining
Bolts
N
S
m
Bolts
4.0
9.2
19
33
53
80
117
161
286
447
651
837
Nore: These values are based upon standard materials, S66286/Inconel screws and ASTM A193GRB6 bolts. For other special fasterer materials, please contact your Fisher Controls
sales office or sales representative.
final bolting torque. Repeat this procedure several
times increasing the torque value each time by a
fourth of the final desired torque. When you get to the
final torque value, tighten each flange bolt again to
allow for gasket compression.
Maintenance
Valve parts are subject to normal wear and must be
inspected and replaced as necessary. The frequency
of inspection and replacement depends upon the se-
verity of service conditions. Because of the care Fish-
er Controls takes in meeting all manufacturing require-
ments (heat treating, dimensional tolerances, etc.),
use only replacement parts manufactured or furnished
by Fisher Controls.
WARNING
Avoid personal injury from sudden re-
lease of process pressure. Before per-
forming any maintenance operations:
D
Disconnect any operating lines pro-
viding air pressure, electric power, or a
control signal to the actuator. Be sure
the actuator cannot suddenly open or
close the valve.
D
Use bypass valves or completely
shut off the process to isolate the valve
from process pressure. Relieve process
pressure on both sides of the valve.
Drain the process media from either
side of the valve.
D
Vent the power actuator loading
pressure and relieve any actuator spring
precompression.
Figure 5. Properly Installed Wafer Style Valve
A5557/IL
D
Use lock-out procedures to be sure
that the above measures stay in effect
while you work on the equipment.
Replacing Packing
The Type A31A valve is designed so the packing can
be replaced without removing the valve from the pro-
cess pipeline. Packing may be PTFE V-rings or graph-
ite.
If you are installing an ENVIRO-SEAL Packing System
in an existing valve, follow the instructions in the
EN-
VIRO-SEAL Packing Instruction Manual (Form 5320).
To remove packing parts in a valve with the ENVIRO-
SEAL packing system, follow the procedures for
valves using ENVIRO-SEAL packing system in this
section.
For valves with PTFE or graphite packing:
Key numbers for the parts in this section may be found
in figure 7.
