Valve Maintenance; Valve Disassembly And Reassembly; Disassembling The Body; Quick Check - Flowserve Valtek Mark One Installation, Operation & Maintenance Instructions Manual

Quick-check
Prior to start-up, check the control valve by following
these steps:
1. Stroke the valve and observe the plug position
indicator on the stem clamp compared to the stroke
indicator plate. The plug should change position in
a smooth, linear fashion.
2. Check for full stroke by making appropriate instru-
ment signal change: 3-15, 3-9, 9-15 psi / 0-1, 0-0.6,
0.6-1 Bar or associated split ranges for pneumatic
positioners, 4-20 or 10-50 mA for electro-pneu-
matic positioners).
3. Check all air connections for leaks.
4. Adjust the packing nuts to slightly over finger-tight.
CAUTION: Do not overtighten packing. This can
cause excessive packing wear and high stem
friction that may impede plug movement.
5. Make sure the valve fails in the correct direction in
case of air failure. This is done by shutting off the air
supply and observing the failure direction.
6. After temperature excursion has occurred, bonnet
flange bolting should be retightened to ensure bon-
net gaskets do not leak. See Table III.

VALVE MAINTENANCE

At least once every six months, check for proper opera-
tion by following the preventative maintenance steps
outlined below. These steps can be performed while the
valve is in-line and, in some cases, without interrupting
service. If an internal problem is suspected, refer to the
"Valve Disassembly and Reassembly" section.
1. Look for signs of gasket leakage through the end
flanges and bonnet. Tighten flange and bonnet
bolting (if required). See Table III.
2. Check for fluid leakage to the atmosphere through
the pressure-balance sleeve, metal bellows seal
and body drain plug.
3. Examine the valve for damage caused by corrosive
fumes or process drippings.
4. Clean valve and repaint areas of severe oxidation.
5. Check packing box bolting for proper tightness.
Packing nuts should be slightly over finger-tight;
however, tighten only as necessary to prevent stem
leakage.
CAUTION: Do not overtighten packing. This can
cause excessive packing wear and high stem
friction that may impede stem movement.
6. If the valve is supplied with a lubricator fitting, check
lubricant supply and add lubricant if necessary. See
Table II for common lubricants.
1-4
7. If possible, stroke the valve and check for smooth,
full-stroke operation. Unsteady stem movement
could indicate an internal valve problem.
NOTE: Jerky stem motion is normal whenever
graphite packing is used.
WARNING: Keep hands, hair and clothing away
from all moving parts when operating the valve.
Failure to do so can cause serious injury.
8. Make sure positioner linkage and stem clamp are
securely fastened. If the stem clamp is loose, check
plug thread engagement (refer to the "Reassem-
bling the Actuator" section for the correct procedure
on aligning the plug with the seat.)
9. Ensure all accessories, brackets and bolting are
securely fastened.
10. If possible, remove air supply and observe actuator
for correct fail-safe action.
11. Check rubber bellows for wear.
12. Spray a soap solution around the cylinder actuator
retaining ring, adjusting screw and actuator stem
guide to check for air leaks through the O-rings.
13. Clean any dirt and other foreign material from the
plug stem.
14. If an air filter is supplied, check and replace car-
tridge if necessary.

VALVE DISASSEMBLY AND REASSEMBLY

Disassembling the Body

To disassemble the valve body, refer to Figures 1 and
4 then proceed as follows:
WARNING: Depressurize line to atmospheric pres-
sure and drain all fluids before working on the
valve. Failure to do so can cause serious injury.
1. If valve is air-to-open, apply air under the piston to
lift the plug off the seat before taking the valve apart.
If valve is air-to-close, proceed to step 2.
2. Remove the bonnet flange bolting and lift actuator,
bonnet and plug out of the valve.
CAUTION: Heavy actuators may require a hoist.
Lift the valve with the yoke legs using a lifting
strap and a hoist. Great care should be taken to
lift the actuator and plug straight out of the body
to avoid damage to the plug and seat.
3. Lift retainer, seat ring and gaskets free of the body.
4. Check to see the seating surfaces on both the seat
ring and plug are free of damage to ensure tight
shutoff. Make sure the gasket surfaces on the seat
ring, bonnet and body are clean and undamaged.
5. To inspect the plug, remove by loosening the stem
clamp and gland flange and by taking off the yoke
clamps.
Flowserve Corporation, Valtek Control Products, Tel. USA 801 489 8611