Subsea Repair Clamp for Leaking Valve

[RandomAxe]

Does anyone have any experience of installing a clamp or similar onto a leaking valve? We have a several leaking valves and there are concerns regarding integrity (obviously) and we have been advised that preferred solution is to not operate valve or access gearbox etc due to concerns of making things worse and creating further leak paths (dodgy seals). I've been looking online but can only find examples of repair clamps installed on pipelines and tubulars, something similar would work but I have been unable to find an example. Any other ideas welcome...
Thanks

 

[BigInch]

Valves usually leak from the stem packings. Add sealent.
There are no clamps for valves that I know of.

 

[chicopee]

BI, how would one apply sealant to leaking valve packing under water, and presumably with the subsea line under pressure? Based on the question, it seems that the leaks are occurring at the valve connections.

 

[georgeverghese]

Sounds like the leak is through the stem packing out into the seawater ?

 

[BigInch]

With a weld-end valve, connections should remain relatively secure. Do you think they used flanged valves offshore? Not the best idea.

Sealant would have to be applied by divers or ROV using pressured grease gun.
Grease can be applied through lube fittings, even if line is under internal pressure. Hopefully the valve was ordered with lube fittings, right?

http://www.wegman.nl/downloads/WM - Installation and maintenance manual Cam T31.pdf

Although that says not to inject into stem fittings

 

[RandomAxe]

Thanks for responses. There are no injection ports provided on this valve, and I can't see us getting approval to drill one.

Why wouldn't you use flanged valves? 95% of subsea structures I've seen have flanged valves(North Sea), replacing a welded valve is a lot more expensive?

 

[BigInch]

Good welded valves from reputable manufacturers if they ever leak at all, will usually only leak a relatively small amount through the stem. Best is to order only highly qualified welded valves for offshore service. Ones that won't ever leak. You don't build offshore subsea pipeline systems with the intention to repair easily. Design with intent to never fail is by far the cheapest solution for long term offshore service. Sometimes at subsea tie-ins, flanged valves are the only practical solution, but if you don't have to use flanged valves, then don't.

 

[LittleInch]

" We have a several leaking valves "

Where are the leaks?
Stem?
Body?
Body flange?
end flange?
Internal seal?

If stem what is seal arrangement? Can you post a cross section?
If internal seal what are seats made of?
Pressure?
Actuators / manual / ROV?

If you could find such a clamp, this would mean your valve would probably become inoperable. Is this acceptable?

what is access like?

Is it inside a structure?

Give us a bit of a clue here and you might get some more targeted responses.

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