Non-Destructive examination of ball valves 2

[mkarpash]

do anyone knows anything about non-destructive examination of burried steel ball valves?
in ukraine we have got a lot's of problem with them.
before we dig it out and replace (which is not really cheap) we would like to know whether it leaks and if yes how much.

 

[terje61]

Hello Mkarpash,

You can do sonic leak detection from the outside of a valve. It does help if you have done regular leak measurements on the particular valve (before and after leaking) in order to clearly detect the difference.

For burried valves you need to get to the valve body. This probably means that you have to do some digging, but you do not have to bring it to surface.

More details regarding the sonic leak detection can be found on:

http://www.clampon.com/art.cfm?c_id=45195&c_kat=6918&c_subkatid=45195&showflash=0

Best regards,
Terje

 

[mkarpash]

Dear terje61,

thank you very much. i've heard about the sonic inspection but didn't know where to find equipment.
your link is very useful.
don't you know anything about normative documents regarding this theme?

again thank you very much. i appreciate this.

regards,
mkarpash

 

[terje61]

Sorry, I do no know of any normative documents. I was told that this technology was developed to detect submarines. So maybe there is more information in the naval defence field. Although this is likely to be classified.
In the oil/gas sector it is quite new and using the detectors assume a learning curve for each valve type.

I used them on a set of critical valves and the difference between leakage free and leaking was very easy to detect. The location of the leak path is more difficult to establish.

M.v.h.
Terje

 

[caihui]

I think you can add some atom which can be inspected by a specific equipment in the flow. And then you can know where leakage. But I don't know what kind atom used. Maybe this information is useful for you. As I heard someone verify his landlord orts to him so he add something in the fresh and then check the next day dish. I remeber he used a kind of inert atom. Sorry can't give u more.

 

[mkarpash]

dear caihui,

thank you very much for the advise. we discussed this idea but due to a certain limitations in standards for natural gas we can't add anything like inert gases. we thought about inserting some waves in one part of the spectrum (gamma rays, or something). but in this case we'll get additional safety requirements to be applied....
anyway thank you. this will let me think more widely.

 

[unclesyd]

Is the process fluid natural gas?

There is a possibility that you maybe able to get a detector that is very sensitive to one of you gas stream components. We had a demonstration of one type that was extremely sensitive to Methane.

I've used Helium with a portable He detector to check underground lines. The equipment I used was developed for the telephone company to detect leaks in buried telephone cables.

 

[mkarpash]

dear all who have contributed to this thread,

may there is some missunderstanding in the problem statement.
actually we look for the leaks inside the pipe line, not into outside area.

if anyone has ideas, i will appreciate this.
thanks anyway.

 

[unclesyd]

As mentioned above ultrasound would be a very good way to go.
Though I've never tried it I once proposed that we punch a hole through the cement and dirt covering a pipe to the detect a possible leak. This hole would enable us to get a ultrasound microphone in close proximity to the pipe.

Here is one company that you may contact with your problem.
There are several others that make good equipment.

http://www.uesystems.com/