Flowserve V-377 R4 Edward Valves - Manual (Page 48)

48
Flow Control Division
Edward Valves
General Information
WARNING
Edward valves are not provided with a
pressure relief device. A pressure relief
device must be provided elsewhere in the
piping system to prevent the piping system
pressure from exceeding the maximum
rated pressure of the valve.
Welding Valves Into Piping
Welding is outside the scope of this manu-
al, but Edward recommends you consult the
appropriate welding procedure in
ASME/ANSI B31, or whatever other codes
apply to your system. When welding valves
into piping, make sure there is no foreign
material on the seat joint, then close the
valve tightly to avoid distorting the seats.
During subsequent stress relief of the welds,
leave the valve closed to avoid distorting
the valve seat. Also, during stress relief,
assure that the valve upperstructure is not
overheated. After welding and stress relief,
open the valve and flush the line to clean
out all foreign matter.
Piping Support
Piping should be supported sufficiently to
preclude excessive end loads on the valve.
Valve Installation Guidelines
Except as noted below, Edward stop valves
can be installed in any position. Installed
positions with the valve cover or bonnet
below horizontal, where dirt and scale can
accumulate in the valve neck, should be
avoided. The orientation limits shown in
Figures 1- 4 must not be exceeded for
Edward Stop-Check valves and Check
valves. The limitations given for line inclina-
tion and bonnet roll angle should not be
combined.
All Check and Stop-Check valves should be
installed with 10 or more diameters of
straight pipe upstream of the valve to mini-
mize flow disturbances. For additional
information, refer to the “Technical” section
of the Edward Valves Catalog, Publication
No. EV-100.
Notes on Valve Operation
Valves equipped with electric motor actua-
tors have special tags attached which indi-
cate the correct torque switch setting for the
valve. Exceeding these torque switch set-
tings can cause damage to the valve.
Never use an electric motor actuator to
back-seat a valve. This can result in dam-
age to the valve stem and bonnet backseat.
Notes on Valve Maintenance
When replacing the bonnet gasket in
Edward valves, follow the torque require-
ments closely. Failure to torque the bonnet
bolting properly will result in gasket failure.
When replacing the valve stem packing,
never machine the packing chamber over-
size. This will result in blowout of the pack-
ing.
Lubrication
In order to obtain full service life, valves
require periodic lubrication of the stem
threads. Exposed threads should be wiped
clean of old grease and accumulated dirt.
Fresh lubricant should then be applied. This
is most effectively done with the valve in the
closed position. For valves that see frequent
operation, such as motor actuated valves,
the lubricant should be replenished every
three months. If extreme service conditions
dictate, a more frequent relube schedule
is recommended. The recommended
lubricant for all stem threads is Rykon
EP #2, manufactured by the American Oil
Company. This is an extreme pressure,
extreme temperature lubricant of high
quality. For valves that are operated
infrequently, relubrication should be at
least once a year.