Flowserve Valtek Mark One and Mark Two Control Valves - Manual (Page 11)

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Valtek Mark One and Mark Two Control Valves FCD VLENIM001-01-AQ - 8/14
ers permit a wide variety of packing configurations, such as
twin seal and vacuum-pressure packing.
CAUTION: Valves with extended bonnets or metal bellows
seals must not have lower packing installed. Instead, lower
packing rings should be installed with the upper set. Lower
packing installed in extended bonnets or metal bellows seal
valves will diminish the integrity of the packing assembly.
NOTE: Guide liners should be replaced each time the valve
packing is replaced. Do not rebuild the valve without the
correct guide liners.
7.3. Re-insert the plug stem into the packing box, being careful
not to score the plug stem or the guides. Reinstall pressure
balanced seals if required.
7.4. Turn actuator back onto the plug, without turning the plug
inside the bonnet. Make sure the gland flange and bonnet
flange are in place before engaging the plug stem and actu-
ator stem threads. The gland flange chamfer must be face
down towards the valve body. Leave approximately three
to four plug stem threads exposed. Attach yoke clamp and
gland flange bolting. For valves with a 2-inch spud, be sure
the half rings are in place between the yoke and bonnet.
Firmly tighten yoke clamp bolting. The packing box nuts
should be just over finger tight.
NOTE: Do not allow the gland flange to contact and gall the
polished plug stem.
7.5. Install new bonnet and seat gaskets with the bevelled edge
up for Teflon gaskets.
7.6. Insert the seat ring into the body with the step side down.
When the seat ring is properly in place it will turn easily in
the body. Place the seat retainer into the body with the thin
end of the cathedral window down. Most retainers have an
arrow pointing up to verify correct installation. For pressure
balanced valves, install the pressure balanced sleeve gasket.
Ensure that severe service retainers are correctly indexed by
turning the retainer in the body. Correctly aligned retainers
should turn easily.
CAUTION: Installing seat retainers upside down can damage
the control valve parts.
CAUTION: Seat rings, retainers and pressure balanced
sleeves must be installed squarely into the body to function
correctly. To check to make sure the parts are installed cor-
rectly, rotate these parts a little by hand. The parts should
rotate freely without binding.
NOTE: When the seat retainer has only two ports, one of the
two ports should be aligned with the upper port of the body.
7.7. Place air under the actuator piston on air-to-open valves to
retract the plug.
7.8. Lower the plug and bonnet squarely into the body. Be care-
ful not to scratch or gall the plug as it enters the body.
7.9. To properly align the seat ring and plug, first bring the bon-
net bolting to finger-tightness.
7.9.1. With pneumatic actuators, apply air pressure above the pis-
ton to seat the plug in the seat ring. Proceed to step 7.10.
7.9.2. With electric or hydraulic actuators, move the actuator stem
down until it is completely extended. Next, retract the actu-
ator stem 1/8 inch (3.2 mm). Install the stem clamp onto
the plug stem and actuator stem and tighten the associated
bolting. Move the actuator stem completely down. Adjust
actuator limit switches according to the actuator’s operating
manual. The actuator limit switches will need to be readjust-
ed once the body bolting has been tightened.
NOTE: Step 7.10 applies only to valves with pneumatic actu-
ators. If an electric or hydraulic actuator is used, return the
plug to the mid-stroke position and proceed to tighten.
CAUTION: Failure to return the plug to a mid-stroke position
(electric or hydraulic operators only) will cause damage to
the actuator and / or the valve during the bonnet tightening
sequence. This is due to the inability of most electric / hy-
draulic actuators to accommodate the 1/16 inch / 1.60 mm
back-drive during the tightening sequence.
7.10. For air-to-close valves, skip this step and go to step 7.11. For
air-to-open valves, check for proper plug seating as follows:
When proper seating occurs, the bonnet flange will be forced
up against the finger-tight body bolting with such force that
it will be impossible to move the flange. If proper seating
does not occur, the bonnet flange can be wiggled with light
hand force for small valves and light wrench force for larger
valves. Should this occur, place air under the actuator piston
and retract the actuator to approximate mid-stroke position.
Turn the plug out of the actuator plug stem one additional
thread and repeat above seating procedure. When the bon-
net flange becomes tight against the finger-tight body bolt-
ing, the plug is properly seated. If necessary, repeat above
procedure until proper seating occurs.
7.11. Stroke the valve open and closed several times to center the
seat ring. Retract the plug (open position). Begin tightening
the bonnet flange bolting in a manner that will keep the bon-
net flange square / parallel with the body. Tighten the first
bolt 1/6 turn, or one nut flat, then tighten the bolt directly
opposite 1/6 turn and so on around the flange. Firmly tight-
en all bolts evenly and completely to compress the bonnet
gasket and to seat the bonnet. Torque the bonnet bolts to
the suggested torque values in Table II. The bonnet will seat
metal to metal with the body when the bonnet bolts are cor-
rectly torqued into place