Black deposits on fresh water side plate coolers

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

Black deposits on fresh water side plate coolers

Postby Aavenger » Wed Nov 21, 2018 5:05 am

These coolers are part of lt system on ferry black deposits on FW
Side and sludge in header tank?New ship 2<. Years old?
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Big Pete
Engineering Mentor
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Joined: Fri Apr 24, 2009 11:18 pm
Currently located: Solihull, England

Re: Black deposits on fresh water side plate coolers

Postby Big Pete » Wed Nov 21, 2018 12:48 pm

Poor cooling water treatment. The pipe work is rusting to form Black Iron Oxide (due to lack of Oxygen) which is dissolving in the circulating water and being deposited by Galvanic action onto the Heat Exchanger Plates which are less re active than the steel pipes.#

Same as the steel Hull corrodes, and tries to plate itself onto the Bronze Propeller, but is constantly eroded by the turbulent water flow, over the prop.

You need to power flush the system out with detergents to clean it and then maintain correct cooling water treatment.
Merry Xmas,

Big Pete
It is always better to ask a stupid question than to do a stupid thing.

TDC
Deck Plate Wanderer
Posts: 23
Joined: Wed Jul 19, 2017 3:40 am
Currently located: St. Johns, NL

Re: Black deposits on fresh water side plate coolers

Postby TDC » Wed Jan 02, 2019 7:51 am

We recently had similar on 2 of our fleet vessels. What we found was that both vessel had replaced rubber expansion joints in the last year. There is a color coded for these indicating they are made with different materials depending on the application. The new expansion joints we purchased had a yellow color band and were meant to be used in water systems but there is a red color code for expansion joints to be used with water treatment. We used maxi guard as a treatment and it attacked the rubber in these joints causing black sludge in the coolers and turned the normally pink colored water to cold black.
Hope this helps.
TDC

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

Re: Black deposits on fresh water side plate coolers

Postby Aavenger » Sat Jan 05, 2019 6:52 am

Thanks guys


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