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NotchFlo DST Valve
March 2011
When all nuts are tightened to that torque value, increase the torque by 1/4 of the specified nominal torque and
repeat the crisscross pattern. Repeat this procedure until all nuts are tightened to the specified nominal value. Apply
the final torque value again and, if any nut still turns, tighten every nut again.
Note
When installing packing rings, prevent entrapping air between the rings. Add the rings one at a time without forcing them below
the chamfer of the packing box entrance chamber. As each successive ring is added, the stack should not be pushed down more
than the thickness of the added ring (figure 6).
15. Install new packing and the metal packing box parts according to the appropriate arrangement in figures 3, 4, or
5. If desired, packing parts may be pre‐lubricated with a silicon base grease for easier installation. Slip a
smooth‐edged pipe over the valve stem, and gently tap each soft packing part into the packing box, being sure that
air is not trapped between adjacent soft parts.
16. Slide the packing follower, wiper, and packing flange into position. Lubricate the packing flange studs (key 20) and
the faces of the packing flange nuts (key 21). Install the packing flange nuts.
For the spring‐loaded PTFE V‐ring packing shown in figure 3, tighten the packing flange nuts until the shoulder on the
packing follower (key 28) contacts the bonnet.
For graphite packing, tighten the packing flange nuts to the maximum recommended torque shown in table 3 or 4.
Then, loosen the packing flange nuts, and retighten them to the recommended minimum torque shown in table 3 or
4.
For other packing types, tighten the packing flange nuts alternately in small equal increments until one of the nuts
reaches the minimum recommended torque shown in table 3 or 4. Then, tighten the remaining flange nuts until the
packing flange is level and at a 90‐degree angle to the valve stem.
17. Mount the actuator on the valve body assembly, and reconnect the actuator and valve plug stems according to
the procedures in the appropriate actuator instruction manual.
Trim Removal
Key numbers referenced in this procedure are shown in figures 7 through 12, except where indicated.
1. Remove the actuator and bonnet by following steps 1 through 6 of the replacing packing procedure. Observe all
warnings and cautions in that procedure.
2. Lift the valve stem and attached valve plug out of the valve body. If the valve plug is to be reused, tape or otherwise
protect the valve plug stem and the valve plug seating surface to prevent scratches.
3. Lift out the cage (key 2), the bonnet gasket (key 11), and (if applicable) the cage gaskets (key 65).
4. Remove the seat ring (key 4) and the seat ring gasket(s) (key 12).
5. Inspect the parts for wear or damage and replace if needed.
6. Refer to the Valve Plug Maintenance procedure or to the Lapping Seats procedure.
Valve Plug Maintenance
Key numbers used in this procedure are shown in figures 7 through 12, except where indicated.
1. With the valve plug (key 5) removed according to the trim removal procedure, proceed as appropriate:
For the NPS 1 and 1‐1/2 CL900 or 1500 NotchFlo DST valves, proceed to step 2.
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Instruction Manual
D103211X012
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