cashco 987 Manuel d'installation, d'utilisation et d'entretien - Page 11

Parcourez en ligne ou téléchargez le pdf Manuel d'installation, d'utilisation et d'entretien pour {nom_de_la_catégorie} cashco 987. cashco 987 15 pages. Globe-style pneumatic control valve body iom

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4.
Valve exhibits "excess" seat leakage.
Possible Cause
A.
Excess pressure drop.
B.
Improper actuator bench setting.
C. Metal seat design instead of composition seat design. C.
D.
Excess wear.
E.
Misalignment.
F.
Composition seat failure.
G.
Seat ring gasket failure.
5.
Premature packing leakage.
Possible Cause
A.
Over-temperature.
B.
Misalignment.
C. Wear.
D. Improper design for applied service.
E.
Corrosion of stem.
6.
Bonnet gasket leaking.
A.
Improper bonnet bolting draw down.
B. Corrosion.
C. Over-temperature.
IOM-987
Possible Cause
Remedy
A1.
Reduce pressure drop conditions.
A2. Convert to reduced trim.
B1.
Calibrate actuator-to-valve.
B2.
Assure proper engagement of act.stem to valve stem.
Convert valve to composition seat.
D1. Oversized valve operating too close to seat, convert to
reduced trim.
D2. Remove particulate.
D3. Possible excess cavitation in liquid service, change
operation parameters.
D4. Re-lap plug-seat surface.
E.
Realign body-stem-actuator.
F1.
Replace soft seat.
F2.
Remove "dirty" portion of fl uid causing failure.
G.
Replace seat ring o-ring.
A1.
Bring process temperature to 450
A2.
Remove insulation along bonnet; allow direct contact
with ambient air.
B.
Realign body-stem-actuator.
C1. Remove dirt/grit from fl uid.
C2. Reduce cyclic travel.
D.
Install alternate packing design.
E.
Consider use of Model 988 or 989 or 2296.
A.
Replace bonnet o-ring and draw down bolting evenly.
B.
Consider use of Model 988 or 989 or 2296.
C.
Bring process temperature to 450
Remedy
F (232
C) or less.
°
°
Remedy
F (232
C) or less.
°
°
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