36'' butterfly valve stuck how to operate online?

[shetty0107]

36'' butterfly valve operated by motor in one of chemical company. during plant running time valve is stuck. We disconnect the Motor and try to close manually. But not possible to close 100% ONLY 44% closing. but we don't have any isolation valve ,so we need to solve by online. any one can give good ideas. Please...

 

[pennpiper]

shetty0107,
You don't say where you are or what you have already discussed.
So I will suggest one option:
- Contact a "Hot-Tap Specialty Contractor.
- Discuss an Upstream & Downstream Stopple and Bypass arrangement.
- Drain the isolated portion with the Valve then cut it out.
- Replace the Butterfly Valve
- Remove the Bypass and Blind off the bypass connections.

Sometimes its possible to do all the right things and still get bad results

 

[Gator]

How do you know the valve is "44% closed"?

Piping Design Central

 

[LittleInch]

Debris or solid object?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[shetty0107]

Mr. Gator . we have the power display showing the percentage of valve position.
Mr. Little inch: your correct saying. may be support broken or else slug. this is 42'' butterfly valve. and hydrocarbon line . thank you for suggestions.

 

[shetty0107]

Mr. Penn piper thank you for suggestion. without hot tapping any other ideas? this line is 42''

 

[Gator]

OP says the butterfly valve is 36", now it's 42"

What is the fluid service in the line?

Piping Design Central

 

[shetty0107]

42'' hydrocarbon line...

 

[pennpiper]

shetty0107,
The fact the line is 42" does not make a difference to my suggestion. Don't try to second the Hot-Tap people. Contact them and let them tell you what can and what cannot be done to correct your problem.

Sometimes its possible to do all the right things and still get bad results

 

[racookpe1978]

Yes,we understand it is hydrocarbon. What hydrocarbon is in the pipe? Is it turbulent (now) or pulsing or cavitating since the valve "may be" only 42% open? Those valves of that size are not intended for throttling position - only full open, full shut.

Are you ABSOLUTELY SURE the valve is actually rotating - I don't care what the inticator says, drive out to the valve and see what is really happening! Bad indicator, bad motor (have you changed it yet?), bad controller but good motor, bad motor power supply, bad clamp between motor/actuator and valve stem? You must eliminate every chance of any of those before continuing.

Also - can you stop flow in the pipe, then try closing (or opening) the valve again?

 

[bimr]

Have you contacted the manufacturer of the valve and had the representative inspect it? Probably worth the cost as a valve that size and consequently the repairs will be expensive.

 

[shetty0107]

Hydrocarbon like Ethane and butane. 280. C line temperature and valve is 42'' butterfly valve. no more isolation valve...may be inside support broken.

 

[racookpe1978]

Demand a service inspection, pull the operator off of the valve. The key between actuator and valve shaft might have sheared.

 

[shetty0107]

we cannot close the valve 100%. very hard movement.

 

[racookpe1978]

Recognize that you cannot repair NOR replace the valve - whether open or shut or in-the-middle - without first isolating and venting and releasing BOTH sides of the valve all the way to the previous tank or valve, and removing or blowing out the explosive gasses from BOTH sides of the pipeline into a below-explosive-level percentage.

It is impossible to work on "one-half" of a a stuck or jammed isolation valve that is itself isolating the fluid you need be protected from.