Side Entry Ball Valve - Leak From Bonnet Stud 1

[Aptx4869]

Hi All

We have a minor leak (one drop every few seconds) from side entry ball valve. The location of leak is shown in attached picture. The leak is not that much but it is hazardous since the media is diesel.

The leak is coming from the bonnet stud. The valve is connected to a diesel tank with no isolation point in between and we want to fix the leak without emptying the full tank. The system flanges are rated for Class 150 and Temp is ambient.

One vendor offered to enclose the leak with a shell, but that will take minimum 4-5 weeks for fabrication

Is there any other valid solution ?

Thanks

 

[bcd]

You can try to tighten the nuts on the body joint some more. That is your only option other than to put something underneath to capture the leak-off and collect in a safer container.

 

[mk3223]

Contact leak seal repair expert, such as

https://www.teaminc.com

for an emergency fix with "belt" bandage with sealant, as well as a temporary fix.

 

[TugboatEng]

I would suggest installing a spray shield. A diesel leak isn't especially hazardous so long as it's not atomizing or spraying on to hot surfaces.

A diesel leak can be an environmental concern so a proper containment should be considered. I assume your application is not marine.

 

[Andrew ONeill]

From my experience in refineries, you really only have a couple of options for leak sealing

1) Take an equipment outage and replace the item ->This should be the first action taken in all cases, unless there is a real reason this can't be done
2) Tighten up the bolts
3) Wrap it with some sort of fibreglass, kevlar, etc
4) Install a clamp, unusually is then filled with some sort of magic filler goo
5) Weld a steel patch over it
6) Leave it

The key consideration for all of these is having an understanding of the consequences involved. My mental checklist is normally
1) What is the design pressure & temperature, relative to what is installed? -> In this case it might be #150 valve, but only have say 200kpa pressure on it?
2) What is the fluid, and can it hurt people or the environment
3) when is the next opportunity to replace the item (is it 4 weeks or 10 years away) ->This gives you an idea of how permanent the temporary fix needs to be
4) If this all went wrong, could I explain it to a judge in a courtroom.




Andrew O'Neill
Specialist Mechanical Engineer
Rio Tinto
Australia

 

[Aptx4869]

Thank you all. We contacted sealing solution company and they injected compound sealant at each stud.

 

[TugboatEng]

Did it work?

 

[Aptx4869]

Yes. So far the leak is stopped and it is been 5 days.

Basically small holes drilled on the flange face at each stud and injected with sealant. As the sealant is being injected, the leak is increasing in stud and flange face as the sealant is purging the diesel that is inside. Expected to last few months at least

 

[TugboatEng]

Interesting. I'd be curious to know the product use.

 

[Aptx4869]

https://niccoengineering.com/product/online-leak-sealing-compound-nes-6c/

 

[IFRs]

How did they seal the holes that they drilled?