Instruction Manual
D100425X012
YD and YS Valves
October 2014
14
12. Lubricate the valve stud bolts or cap screws (key 15) and install the nuts (key 16) on the bolts using accepted
bolting practices. Tighten the nuts to the recommended bolt torques given in table 5. Follow a pattern similar to
that shown in figure 8.
Note
It might be necessary to repeat the bolting pattern several times until the bonnet-to-body seal is made, because the tightening of
one nut might loosen an adjacent nut. Repeat the pattern until none of the nuts will turn at the recommended torque.
13. Mount the actuator on the bonnet and make up the stem connection according to the procedure given in the
appropriate actuator instruction manual.
YD (High Temperature)
1. Use new gaskets, seals, and shim (keys 9, 11, 13, 14, 19, 20, and 22) on assembly and wipe all sealing surfaces with
acleancloth.
2. For NPS 8 YD, install the bottom flange adaptor (key 24) and gasket (key 9).
3. Install the seat ring gasket (key 14) and place the seat ring (key 8) on top of the gasket followed by the spiral wound
spring (key 13).
4. Install the lower cage (key 4) into the valve, being certain that it fits down over the raised portion of the seat ring.
Thenarrowportionofthecagewindowsshouldpointdownward.
5. Place one of the retaining ring gaskets (key 19) into the valve.
6. If a new stem (key 5) is to be used, screw the stem into the valve plug (key 2) until it wedges tight at the end of the
valve stem thread.
CAUTION
Never use an old stem with a new valve plug. The use of an old stem requires drilling a new pin hole through the stem (or
adaptor, in case an ENVIRO-SEAL bellows seal bonnet is being used). This drilling weakens the stem or adaptor and may
cause failure in service. However, a used valve plug may be reused with a new stem or adaptor.
Locate the pilot hole in the valve plug and drill the hole through the plug and stem assembly (determine drill size from
table4).Driveinthepintolocktheassembly.
7. For ENVIRO-SEAL bellows seal bonnets, grip the flats of the stem extending out of the top of the bellows shroud
with a soft-jaw chuck or other type of vise. Screw the valve plug/adaptor assembly onto the valve stem. Tighten as
necessarytoalignthepinholeinthestemwithoneoftheholesintheadaptor.Securetheadaptortothestemwith
anewpin.
8. Place the seal ring retainer (key 3C) into the valve and lower the valve plug assembly into the retainer orifice.
9. Carefully place the seal rings (key 20) over the valve plug, being certain that they rest against the retaining ring.
Each of these has a cut through its cross section. These cuts should be oriented 180 degrees apart to ensure a
proper seal.
10. Insert the other retaining ring gasket (key 19) on top of the retaining ring.
11. Lower the upper cage (key 3B) into the valve. When properly installed, the raised ring on t he bottom of the cage
should fit snugly into the groove formed by the seal rings and the retaining ring.
12. Place the spiral wound gasket (key 11), shim (key 22), and bonnet gasket (key 9), respectively, over the upper
cage.
(24 Seiten)
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