Premature pipe failure

A place to exchanges questions and ideas of a technical / procedural nature. Go ahead, try to stomp us !
Aavenger
Leak Patrol
Posts: 42
Joined: Tue Jan 17, 2012 1:13 pm

Premature pipe failure

Postby Aavenger » Wed Nov 21, 2018 5:01 am

On a two year old vessel with iccs system salt water pipes
In the cooling system lasting only 6 months.Eaten away
Found shiny pitted areas on sea bay strainer chests,see pics
Anyone seen this before or have suggestions?Also FW Pipe’s on mtu mains premature failure?
Attachments
62A4F972-C2FC-4517-9349-ECE6E0C73621.jpeg
5AE89B31-98A9-468E-AE39-7C4D41E67FAD.jpeg

User avatar
Big Pete
Engineering Mentor
Posts: 876
Joined: Fri Apr 24, 2009 11:18 pm
Currently located: Solihull, England

Re: Premature pipe failure

Postby Big Pete » Wed Nov 21, 2018 12:51 pm

I suspect that the impressed Current system is either not working correctly or is set up wrongly.
Go back to the Instruction Manual and see if there are set of settings for the "as installed" condition" and see if they are still the same.
It looks as if there is too much current flowing through the system and it is destroying the pipework instead of protecting it.

Merry Xmas
It is always better to ask a stupid question than to do a stupid thing.

User avatar
JK
Enduring Contributor
Posts: 2873
Joined: Tue Sep 04, 2007 2:29 am
Currently located: East Coast, Canada

Re: Premature pipe failure

Postby JK » Thu Nov 22, 2018 5:03 am

Check that the jumper pieces are on the flanges, the gaskets insulate sections of pipe.

On one ship I was on the CE had the main sea strainers coated with Belzona Superglide.

rodrigger
Deck Plate Wanderer
Posts: 20
Joined: Wed Jul 20, 2011 10:06 am

Re: Premature pipe failure

Postby rodrigger » Sat Nov 24, 2018 7:26 pm

have seen this happen on 8 year old vessel. low sea bay suction pipe flange collar erosion all around where the main sea bay valve meet. At dry dock , did thickness measurements and almost 50% wasted away. Rebuilt and machining in suit as per class specification. Next dry dock whole drop pipe will be replaced. No concrete conclusion found and anodes in the sea chest were only 30 ~ 40 % depleted. May have been an inferior weld job at the building yard. ICCP working as designed.

Aavenger
Leak Patrol
Posts: 42
Joined: Tue Jan 17, 2012 1:13 pm

Re: Premature pipe failure

Postby Aavenger » Sat Jan 05, 2019 6:54 am

Thanks

User avatar
Big Pete
Engineering Mentor
Posts: 876
Joined: Fri Apr 24, 2009 11:18 pm
Currently located: Solihull, England

Re: Premature pipe failure

Postby Big Pete » Mon Jan 07, 2019 12:47 am

I recently had an email from an old Cadet of mine and he told me that he was on a Diesel Electric PSV, and they had found that the Electromagnetic field from their 3 phase 690 Volt power cables was inducing a circulating voltage in the pipework! Which I had never heard of before, might be relevant.
BP
It is always better to ask a stupid question than to do a stupid thing.


Return to “The Workshop”

Who is online

Users browsing this forum: No registered users and 0 guests