shutdown valves stuck (problem) and probable cause

7/27/2019 Shutdown Valves Stuck (Problem) and Probable Cause

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

[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

Doc.Eng/BLH/11/07 1 of 3

THE SDV STUCK AND PROBABLE CAUSE

I. SDV FUNCTION

The Shut Down Valve (SDV) = Ball valve + Actuator + Instrument support The SDV have major function in fluid handling system : stopping and starting flow or as Emergency shutdown 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 cause : There are sediments build up around the seat ring valve area due to line contaminates, the

sediments (scaling, dirty, deposit solid content) can arrest to move rotary ball. Ball & seat ring in valve was eroded or damage so valve can not perfect close (stuck or hard

to operated)2. Operator (actuator) is malfunction

Probable cause: Actuator Spring was weak or crooked or damage due to fatigue failure Seal on piston was aging or broken so actuator leaking Stem are too tight and hard to operate due to corrosion product around stem.

3. Instrument support to SDV system have not good condition. For example : Versa valve or solenoid were not good condition.

All probable cause the SDV stuck or hard to operated above are impact too long time SDV have notconducted function test and routine maintenance. The Valve steady in one position could be stuck or hard tooperate.

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. 2. doing Inspection on part of SDV as like Ball valve, Actuator and instrument system. if there are

broken one of the part it so must be replaced and then function test again.

IV. RECOMMENDATION TO PREVENT THIS CASE FOR THE N EXT 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. min per 6 month.

2. Plan to modify the shutdown system to accommodate partial stroke test.
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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 3. Stem are too tight due to corrosionproduct on stem around

Figure 4. The SDV Stuck causes sediment(scaling, deposit solid content) on seat ringarea due to SDV stuck.

Figure 5. Ball in valve was eroded Figure 6. Seat Ring was Eroded


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DETAILED REPORT


Figure 7. Actuator spring was damagecauses fatigue fracture

Figure 8. Seal on piston was broken causesactuator leaking.

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

shutdown valves stuck (problem) and probable cause

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