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Figure 5. Bonnet, Travel Stop, and Seat Ring Installation Detail
40B4190–D
B1972–1 / IL
40B4191–E
SEAT RING
CONTACT SURFACE
SEAT RING
SEALING LEDGE
VALVE
PLUG
(KEY 3)
BELLOWS
(KEY 6)
EQUAL AT ALL
BOLTING LOCATIONS
BONNET
(KEY 2)
0.020 INCH
(0.5 mm) GAP
TRAVEL STOP
(KEY 16)
VALVE
STEM
(KEY 5)
LOCKNUT
(KEY 10)
YOKE
LOCKNUT
(KEY 14)
BONNET
LOCATING
DIAMETER
5. Remove bushing inserts, packing rings, and pack-
ing box ring (keys 13, 12, 28, 29).
6. Clean the packing box, packing box ring, and pack-
ing follower.
7. Inspect the valve stem and packing box surfaces
for any sharp edges that might cut the packing.
Scratches or burrs could damage new packing or
cause packing box leakage. If the surface condition
cannot be improved by light sanding, replace the dam-
aged parts.
8. Install bushing inserts (keys 28 and 29). For metal
bellows, install the gasket (key 27), for 1/2- and
3/4-inch sizes, install the O-ring (key 30) in the bonnet.
9. Install the bonnet (key 2) over the valve stem (key
5). Slide the bonnet down until it properly engages the
bonnet locating diameter (figure 5) of the valve.
Note
In order to ensure accurate positioning
of the valve plug (key 3) and seat ring
(key 4), clearance between the valve and
bonnet at all bolting locations (figure 5)
must be equal and approximately 0.060
inches (1.5 mm) for 1/2- and 3/4-inch
sizes valves and 0.080 inches (2.0 mm)
for 1- through 4-inch sizes valves. Be
sure to measure the clearance in the
next step.