Flowserve Vogt Forged Steel Gate - Manual (Page 34)

Flow Control
Vogt Valves
34 Forged Steel Gate, Globe and Check Valves FCD VVENIM2000-02
O.S.and Y. Welded Bonnet Globe Valves
(Typical Series 2821)
Preferred Method (Requires Disassembly Of Yoke/
Bonnet Subassembly)
1. Loosen packing gland bolting and free up gland.
2. Remove handwheel nut, nameplate, and handwheel.
3. Remove tack weld(s) at yoke/bonnet subassembly. Remove
yoke.
a CAUTION: The stem should be maintained in a near
closed position to ensure that the yoke/bonnet thread
and the stem thread difference do not create a condition
where the stem is locked against the backseat, making
removal of the yoke impossible.
4. Remove top ring of packing. This will be a braided graphite
packing. Remove additional packing as required.
5. Add new rings of flexible graphite packing and one new top ring
of braided graphite packing as required. If total replacement of
packing is necessary, a bottom ring of braided packing shall be
used.
6. Replace the yoke to the bonnet.
a CAUTION: When replacing the yoke the valve stem
should be maintained in an open position to ensure
the yoke thread advance does not drive the disc into
the seat, potentially making the yoke replacement near
impossible.
7. Tighten packing gland bolting evenly.
8. Tack weld yoke/bonnet subassembly at or near the same
location from which the tack weld was removed. Tack weld in
accordance with the manufacturer’s recommended practice.
9. Replace handwheel, nameplate, and handwheel nut and tighten
nut.
10. Open and close valve to ensure free operation.
11. Place valve back in service.
Alternate Method
(No Major Disassembly Required)
1. Remove packing gland bolting and free up packing gland.
2. Remove top ring of packing. This will be a braided graphite pack-
ing. Prepare chamber to accept new rings or rings of packing.
3. Split a number of packing rings of flexible graphite as required
and place individual rings in packing chamber using the gland to
ram the packing into the chamber.
Stagger packing ring’s separations by 90° if more than one ring
is required. Replace top ring of braided graphite packing as
required. If total replacement of packing is necessary, a bottom
ring of braided packing shall be used.
4. Tighten packing gland bolting evenly.
5. Open and close valve to ensure free operation.
6. Place valve back in service.
Inside Screw, Welded or Bolted Bonnet,
Gate or Globe Valve
(Typical Series 12161 and 12181)
1. Remove handwheel nut, nameplate, and handwheel.
2. Remove packing nut and packing gland.
3. Remove top ring of packing. This will be a braided graphite
packing. Remove additional packing as required.
4. Add new rings of flexible graphite packing and one new top
ring of braided graphite packing as required. If total replace-
ment of packing is necessary, a bottom ring of braided packing
shall be used.
5. Replace packing gland and packing nut.
6. Tighten packing nut.
7. Replace handwheel, nameplate, and handwheel nut and tighten
nut.
8. Open and close valve to ensure free operation.
9. Place valve back into service.
5.13 Fluoropolymer
Packing Instructions
For Vogt standard valves packed with Style C-VH packing,
the detailed procedures above may be used as applicable.
Fluoropolymer packing orientation shall be as outlined in Figure 3.