Shutdown Valves Stuck (Problem) and Probable Cause

 

THE SHUTDOWN VALVE STUCK AND PROBABLE CAUSE   by Budi L Hakim (Piping & Valves Specialist) Specialist)  [email protected]   [email protected] 

THE SDV STUCK AND PROBABLE CAUSE  W.O. No:

Report No:

001/VT/IM/11/07

Report Date :

11/23/07 

DETAILED REPORT

THE SDV STUCK AND PROBABLE CAUSE I. SDV FUNCTION The Shut Down Valve (SDV) = Ball valve + Actuator + Instrument support  support   The SDV have major function in fluid handling system : stopping and starting flow or as Emergency shut down valve (isolation process). ESD valves are part of Safety System. The function can be clearly specified in the specification. Quite often specification requires certain safety margins for actuator sizing. Some of above mentioned Safety related standards can be mentioned. The function must be 100% perform. II. The SDV STUCK OR HARD TO OPERATED CAN CAUSED BY: 1.  Valve problem Probable causeare : sediments build up around the seat ring valve area   There ar ea due to line contaminates, the sediments (scaling, dirty, deposit solid content) can arrest to move move rotary ball. damage so valve can not not perfect close (stuck or hard   Ball & seat ring in valve was eroded or damage to operated) 2.  Operator (actuator) is malfunction Probable cause: fail ure   Actuator Spring was weak or crooked or damage due to fatigue failure   Seal on piston was aging or broken so actuator leaking stem.     Stem are too tight and hard to operate due to corrosion product around stem.  3.  Instrument support to SDV system have not good condition.  condition.    For example : Versa valve or solenoid were not good condition. 

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All probable cause the SDV stuck or hard to operated above are impact too long time SDV have not conducted function test and routine maintenance. The Valve steady in one position could be stuck or hard to operate.   operate. III. RECOMMENDATION TO SDV WAS STUCK :  :  1.  Cleaning or greasing inside valve ( seat around) then function test, if still stuck the SDV must be replaced.   replaced. 2.  doing Inspection on part of SDV as like Ball valve, Actuator and instrument system. s ystem. if there are  broken one of the part it so must be replaced and then function function test again.  again.  IV. RECOMMENDATION TO PREVENT THIS CASE FOR THE NEXT IS : :  1.  Inspection and routine maintenance conducted as periodic, as like cleaning / greasing and including function test by Partial stroke device for SDV on line. l ine. min per 6 month.  month.  2.  Plan to modify the shutdown system to accommodate partial stroke test.  test.  

Doc.Eng/BLH/11/07

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THE SHUTDOWN VALVE STUCK AND PROBABLE CAUSE   by Budi L Hakim (Piping & Valves Specialist) Specialist)  [email protected]   [email protected] 

THE SDV STUCK AND PROBABLE CAUSE  W.O. No:

Report No:

001/VT/IM/11/07

Report Date :

11/23/07 

DETAILED REPORT

# ATTACHMENTS (PHOTOS OF CONDITION) SUBJECT : CONDITION CAUSES SDV STUCK OR HARD TO OPERATE Description

Figure 1 The SDV stuck

Figure 2. The SDV Stuck indicate.

Figure Stem are too tight due to corrosion product3.on stem around

Figure 4. deposit The SDVsolid Stuck causes on sediment (scaling, content) seat ring area due to SDV stuck.

Figure 5. Ball in valve was eroded

Figure 6. Seat Ring was Eroded 

Doc.Eng/BLH/11/07

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THE SHUTDOWN VALVE STUCK AND PROBABLE CAUSE   by Budi L Hakim (Piping & Valves Specialist) Specialist)  [email protected]   [email protected] 

THE SDV STUCK AND PROBABLE CAUSE  W.O. No:

Report No:

001/VT/IM/11/07

Report Date :

11/23/07 

DETAILED REPORT

Figure 7. Actuator spring was damage causes fatigue fracture

Figure 8. Seal on piston was broken causes actuator leaking.

Figure 9. Instrument support to SDV system have not good condition. 

Doc.Eng/BLH/11/07

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