Flowserve V-378 R1 Edward Equiwedge Gate Valve - Manual (Page 6)

6
Flow Control Division
Edward Valves
Service Problems
Packing Chamber Leak
Where moisture appears or actual dripping
occurs at the packing chamber around the
stem, gland or gland flange which cannot
be eliminated by re-torquing the gland bolt
the following points should be considered.
1. The packing may have become hard.
Replace the packing.
2. Gland travel has been fully taken up.
Repack with new packing.
3. The wrong packing is being used.
See packing recommendations shown
on this page.
4. A stem should be replaced when it
has become deeply scratched,
burred, or otherwise mutilated from
careless handling, or where the stem
has worn, tapered or has been bent.
5. The gaps in the rings of split packing
have not been staggered around the
stem. They should be inserted in this
manner.
6. The packing gland may be binding
against the packing chamber or stem
and does not compress the packing
properly. Make certain the gland fits
the packing chamber and is tight-
ened down equally on each side.
Packing Recommendations
Edward valves are packed with all-purpose
with packing sets. This is a combination of
packing using braided rings at the top and
bottom in the packing chamber and flexi-
ble graphite packing in the center section.
Packing gland should be tightened down
enough to prevent leakage but not enough
to develop excessive operating torque.
When the gland has advanced approxi-
mately half way into the packing chamber,
it is recommended that additional packing
rings be added. To obtain best results,
the stem should be thoroughly cleaned.
Replacement packing should be the same
as that originally furnished.
We recommend that replacement packing
be purchased from Edward Valves to
assure packing with the proper density and
corrosion inhibitors is always used.
IMPORTANT:
Long service life from modern graphitic
packing requires that adequate preloads
be applied when repacking.
1. All parts should be clean and not
scored or pitted, especially the stem.
2. The valve internal parts and bonnet
should be assembled prior to
installing the packing.
3. Position split packing rings with the
ends of adjacent rings rotated 90°.
4. Install in the following sequence:
Bottom Ring – Braided Ring
Center Rings – Die formed
expanded graphite
Top Ring – Braided Ring
5. Clean and lubricate the gland eye-
bolts.
6. Carefully seat each individual pack-
ing ring before adding the next ring.
7. Apply the recommended torque to
the gland nuts evenly without cocking
the gland. See Table 1, pg. 7, for
recommended torques.
8. Tighten the nuts to the initial values
shown, then loosen and re-tighten to
the final torque.
9. Stroke the valve, then re-check the
gland nut torques.
Note: The torque values given are for
sealing full rated pressure. For line pres-
sures less than the full CWP rating of the
valve, the final torques may be reduced by
the ratio of Pactual/CWP down to a mini-
mum of Pactual = 1500 psig. This will
reduce packing drag and extend packing
life.