Emerson Fisher EHD Instruction Manual page 19

Instruction Manual
D100394X012
b. Use a power torque wrench or driver having torque capabilities equal to or greater than those shown in table 9.
Connect the torque tool to an extension if necessary. The tool or extension must snugly fit the square hole in the
seat ring retainer tool. Refer to figure 9 for square hole sizes.
c. Insert the tool or extension into the square hole in the seat ring retainer tool.
d. Use the stud bolts (key 13) to prevent a power torque wrench from rotating.
CAUTION
Hold the torque wrench at right angles to the seat ring retainer when applying torque. Tilting the tool and extension while
applying torque may cause the lugs on the seat ring retainer tool to suddenly disengage from the recesses in the retainer,
damaging the retainer and seat ring.
e. Tighten the seat ring retainer to the torque shown in table 9.
Note
Some cages have one large window and several small windows. In step 2, install a cage that has different size windows so that the
largest window faces toward the process outlet for a flow‐down and toward the process inlet for a flow‐up valve. Though it may
not be possible to align the large window directly opposite the inlet or outlet, orient the window in the appropriate direction as
much as possible. Incorrect orientation of cage windows causes a reduction of capacity.
2. Proceed as appropriate:
For a valve with a Cavitrol III cage, slide the O‐ring (key 26, figure 21) over the seat ring (key 6) and against the
shoulder in the outer diameter of the seat ring. Install the lower gasket (key 11) between the valve body and cage (key
2), and install the cage. Be certain the lugs on the bottom of the cage engage the corresponding slots in the seat ring
retainer.
For all other valves, install the lower gasket (key 11) between the valve body and cage (key 2), and install the cage. Be
certain the lugs on the bottom of the cage engage the corresponding slots in the seat ring retainer.
Note
Rotate the cage clockwise by hand as much as possible once the cage lugs engage the slots in the seat ring retainer. Failure to do
so may result in leakage at the seat ring to valve body seal.
Constructions other than TSO trim
1. To install the piston rings and seal rings (keys 8 and 30), proceed as appropriate:
For an EHD valve (figure 18), if it is necessary to install new piston rings, the replacement piston rings will arrive in one
piece. Use a vise with smooth or taped jaws to break a replacement piston ring into 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 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 is
not recommended.
EH (1-1/2x1 through 8x6)
July 2017
19