Samson 3351 - Assembly (DN 15 to 80;NPS ½ to 3)

EB 8039 EN 9-7
Servicing
fail-open version together with the plug
stem.
6. To replace the seat and the plug in the
fail-close version, unscrew the seat.
To proceed, position the seat wrench (see
the 'Tightening torques, lubricants and
tools' section in the annex of these in-
structions) on the seat so that its recesses
are aligned with the cams of the seat.
Guidetheseatwrenchovertheplug
stem in the fail-close version. Observe
thespeciedtighteningtorque(seethe
'Tightening torques, lubricants and tools'
section in the annex).
Insert the guide part of the seat wrench
into the body and unscrew seat with a
suitable tool extension.
7. Carefullycleanallparts.Removegasket
(1.2). If the packing leaks, unscrew the
threaded bushing (5.2) in the valve bon-
net and pull out the individual parts, e.g.
V-ring packing (4.2), washer (4.3) and
spring (4.1). When replacing the plug,
renew the packing rings (4.2) as well.
Carefullycleanallpartsandthepacking
chamber.
9.4.2 Assembly(DN15to80/
NPS½to3)
1. In the fail-close version, place the plug in
the body. In the fail-open version, push
plug into the valve bonnet. Thoroughly
degrease the thread of the plug stem.
2. Apply a suitable sealant to the seat and
screw it in using the seat wrench. Ob-
servethespeciedtighteningtorque(see
the 'Tightening torques, lubricants and
tools' section in the annex).
3. Packing:rstinsertspring(4.1)and
washer (4.3) into the packing chamber,
then the V-ring packing parts (4.2) after
applying lubricant to them. Loosely screw
in threaded bushing (5.2).
4. Insert gasket (1.2) into the body. Place
the valve bonnet (5) on the body. In the
fail-close version, lift the plug stem and
carefully guide it through the packing.
Fasten the valve bonnet by evenly tight-
ening the nuts (1.1). Thread the lock nut
(3.2) onto the plug stem until it reaches
the thread end. Place on washer (3.3).
5. Insert spring (5.5) into the valve bonnet
andalignit(seeFig.9-3).Screwspring
plate (5.6) on the plug stem by hand, un-
til it rests on the spring. Align the cam of
the spring plate cams so that it is posi-
tioned above the recess of the dia-
phragm case.
6. Screw on mounting device. Evenly tight-
en clamping bolts until the spring is pre-
loadedapprox.6mmbythespring
plate.
7. Apply a suitable adhesive to the thread
of the plug stem. Position plug wrench or
hex screwdriver and turn the plug stem
counterclockwise until it reaches the plug.
Continuetograduallytensionthemount-
ing device until it rests on the diaphragm
case with its three stop bushings in the
fail-closeversionorapprox.2mmaway
from it in the fail-open version. In this
position, turn the plug counterclockwise