Instruction Manual

Instruction Manual
D100391X012
EDR and ETR Valves
April 2011
8
Installing the Piston Rings or Backup Ring/Seal Rings
1. For EDR: When using a carbon‐filled PTFE piston ring, spread the ring apart slightly at the split, start one end of the
split into the groove in the valve plug. Work the ring around the valve plug inserting the ring into the groove in the
valve plug.
The replacement graphite piston rings will arrive in one piece. Use a vise with smooth or tapered jaws to break the
replacement piston ring into two halves. Place the new ring in the vise so that the jaws compress the ring into an oval.
Compress the ring slowly until the ring snaps on both sides. If one side snaps first, do not try to tear or cut the other
side. Instead, keep compressing the ring until the other side snaps. The piston ring can also be fractured by scoring
and snapping over a hard surface such as a table edge. Sawing or cutting the ring is not recommended.
2. For ETR: Apply a lubricant to both backup and seal rings (keys 25 and 24). Place the backup ring over the stem (key
7) and into the groove in the valve plug (key 3). Slowly and gently stretch the seal ring over the valve plug and work
it into the groove. Stretching the ring over the valve plug can cause it to appear too large for the groove, but it will
contract to its original size when inserted into the cage.
CAUTION
When installing the EDR or ETR valve plug into the cage, make sure the piston or seal ring is evenly engaged in the entrance
chamfer of the cage to avoid damage to the ring.
Note
Use the preceding procedures to assemble the valve plug and stem before installing the parts into the valve body. Insert the valve
plug into the cage (figure 3), then stack the parts as recommended in steps below.
Installing the Parts into the Valve Body
1. Stack the valve trim parts using figures 11 and 12 to determine the sequence of parts.
2. Lubricate the stud bolts (key 15) before installing the valve trim into the valve body. (Note: For ease of installing
trim parts, remove all packing parts from the packing box before installing the trim parts.)
3. When inserting the stack of trim parts into the valve body, carefully align the parts in the recess of the valve body.
4. Slide the bottom flange onto the stud bolts (key 15). Secure the bottom flange (key 31) in place on the valve body
with the hex nuts (key 16). Tighten the hex nuts to the torque value shown in table 3.
5. Torque the nuts in a criss‐cross pattern. Repeat the pattern until all nuts are torqued to the value indicated in table
3.
6. Refer to the Packing Maintenance procedures below.
Packing Maintenance
This procedure covers PTFE V‐ring, graphite ribbon/filament, and PTFE composition packing rings. Key numbers refer
to figure 5 for PTFE V‐ring packing and PTFE/composition packing, unless otherwise indicated.
Note
If the valve has ENVIRO‐SEAL live‐loaded packing installed (figure 8, 9, or 10), see the Fisher instruction manual entitled
ENVIRO‐SEAL Packing System for Sliding‐Stem Valves for packing instructions.