BALL VALVES
PROBLEMS & CAUSES Valve does not open/shut on demand Physical blockage, corrosion, broken actuator, broken stem
Valve partially strokes but does not reach desired position Excessive stem load due to packing or seat friction, actuator problems
Stem packing/seal leakage Normal wear, inadequate packing/seal loading, incorrect installation, incorrect packing set, inadequate packing consolidation, side loading
Seat leakage Foreign material, seat/ball damaged, seat/ball repaired/installed wrong
Valve cavitation/vibration Operating too near the valve seats 262
CRANE PROCESS FLOW TECHNOLOGIES
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TECHNICAL TRAINING
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VALVE & ACTUATOR OVERVIEW