Sacrifical anodes

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adski
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Sacrifical anodes

Postby adski » Wed May 20, 2009 10:07 pm

I have had some conflicting instructions on how to mount sacrificial anodes from engineers whose opinions i respect.
Take the example of a "zinc rod mounted in a brass base" which is to be fitted to a tube type heat exchanger for a sea water system.
1. Do i coat the brass thread in tef-gel or some other compound?
2. Do i fit it bare? I thought this was the right way to do it as there must be some electrical connection for the anode to work...
Thoughts please

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ArkSeaJumper
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Re: Sacrifical anodes

Postby ArkSeaJumper » Thu May 21, 2009 1:25 am

I think the only reason you would put something like this on the threads is so you can easily replace the anode the next time, I would use some grease of copper slip, I had not heard of Tef Gel before but there web site explains ' Tef-Gel does not electrically insulate hardware.'
http://www.tefgel.com/contain.php?param=tefgel_infor

You often would put a rubber disk between the anode and the end plate / cover, again to protect the threads. You are right to think there should be an electrical link between the two to allow electrolysis to happen.

adski
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Re: Sacrifical anodes

Postby adski » Thu May 21, 2009 2:29 am

Ok thanks for the info on both counts. I actually thought that Tef-Gel was an insulator so that clears it up.

astat101
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Re: Sacrifical anodes

Postby astat101 » Wed May 27, 2015 3:25 am

Hi,

I am not sure if this will help at all but there is a company that manufacture diesel engine charge air coolers, you should try Vestas aircoil A/S in Denmark (www.vestas-aircoil.com)


Maybe they can advise.

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Merlyn
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Re: Sacrifical anodes

Postby Merlyn » Wed May 27, 2015 4:35 am

Just done two Caterpillar engine anode changes. As long as it earths out to be the sacrifice required to stop the tube stack being eaten alive I have always found a little smear of copper grease helpful as you do not want a tear on the ones that you have to get upside down on to change again. I always carry drills and taps as when they corrode off flush you can drill and tap them out. As a point of interest here if you fit an easy to get to one with a sealant and then unscrew it again you will see small exposed parts of the brass thread telling you that it has earthed out.
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Big Pete
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Re: Sacrifical anodes

Postby Big Pete » Sun May 31, 2015 1:14 am

Always remember the right anode material for the job!#
Zinc for Sea Water, soft iron for Hot Fresh Water, and I believe craft running on Fresh water use Magnesium Anodes. I have seen several European built engines with soft Iron Anodes supplied for the Fresh Water system and Zinc Anodes supplied for the Sea Water system, dimensions were identical but, the right Anode is determined by the relative positions in the Electro Chemical series of the anode and the material to be protected, which varies between Fresh and Salt water.
BP
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JollyJack
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Re: Sacrifical anodes

Postby JollyJack » Sun May 31, 2015 7:25 pm

While I was Trials Engineer at St John Shipyard, during the "set to work" period, there were dozens of welding cables coming aboard. The sea water coolers were going through zinc anodes like you wouldn't believe! One of the system engineers, well known for his sharp wit, suggested to the Higher Ups that we should use stainless steel instead of zincs, it would last longer. The Person In Charge agreed, causing much merriment in the Trials team. :)
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Merlyn
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Re: Sacrifical anodes

Postby Merlyn » Fri Jun 12, 2015 2:59 am

If that type of situation had happened in the old days over here and especially if the person concerned would have been a know all should the anodes concerned had been pencil anodes some wag would have turned up a set out of SS and posted them to him, a complimentary set for you to try foc . Let us know what you think of them, we guarantee they will last much longer than any of our competors!!
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.

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Merlyn
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Re: Sacrifical anodes

Postby Merlyn » Thu Jun 25, 2015 7:15 am

Spare sacrificial pencil anode for y
image.jpg
our divers watch, well it could be if you still have that old chunky one that you use to pose with in the bath when playing the underwater " hunt the soap " game in your youth. But in what auxiliary does it live? Just about to fit it. It's in smaller engine rooms, it's part of a big brother/ little brother regime , this lives in the smaller one, it's a backup but remains online 24/7 . T'eed off a intercooler and its life is controlled by a wax stat. Not made of zinc but manganese, does not protect a tube stack but funnily enough it does protect of all things a Serpent. It's got a relief valve fitted for hot days and is not changed on an hours run basis but a have a looksee once a year time interval. It's named after a North American Native Indian Tribe and is manufactured but a fast canoe ride down the coast from all you folks who reside in the Nova Scotia district. Expensive up market fancy yacht engine rooms nearly always have them. See on the copper sealant " ok for sensors " although it's been out but a few years it's a relatively new thing and ideal for Cas, camshaft, antiknock and temp sensors who require an insulated earth return circuit. But what's the name of the appliance in which it fits which you need on a daily basis? ( Got caught out on this ship, no feet and inches ruler so blackmailed/ forced to comply here )
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.

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Merlyn
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Re: Sacrifical anodes

Postby Merlyn » Fri Jul 03, 2015 4:27 am

I hear on the jungle drums and smoke signals messaging that the Red Indian Tribe are getting restless as to why all you folk in Nova Scotia can't name their famous device into which the anode shown lives. You must remember that as they are but a fast canoe ride down the coast from you that this also applies vice versa and as such perhaps an acknowledgement might be in order should you be thinking of a peacefull weekend? Keep the powder dry.
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.

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Merlyn
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Re: Sacrifical anodes

Postby Merlyn » Fri Jul 03, 2015 4:28 am

I hear on the jungle drums and smoke signals messaging that the Red Indian Tribe are getting restless as to why all you folk in Nova Scotia can't name their famous device into which the anode shown lives. You must remember that as they are but a fast canoe ride down the coast from you that this also applies vice versa and as such perhaps an acknowledgement might be in order should you be thinking of a peacefull weekend? Else Keep the powder dry.
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.

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Merlyn
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Re: Sacrifical anodes

Postby Merlyn » Tue Jul 07, 2015 7:11 am

Non recognition of where this anode lives is causing unrest among the tribe after whom this device is named, and as such I am now concerned and to that end advance recce party events are being planned as we speak concerning JJ and JK country and the circling of your ranches could shortly begin. BP in his wisdom has virtually told you where it lives, should you not remember this well known name keep the lights on after dark maybe. As we are way over here in the UK we are relying principally on the nearby locals, ie JK and JJ to save the day here and tell us all in what device does it live?
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.

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Merlyn
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Re: Sacrifical anodes

Postby Merlyn » Fri Jul 10, 2015 12:11 pm

Got two R's in the name. See BP's write up May 31 last. There, virtually told you.
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.

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Merlyn
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Re: Sacrifical anodes

Postby Merlyn » Thu Jul 16, 2015 11:37 pm

Another Stompers medal methinks. RARITAN is a hot water tank named after the area near New Jersey US where the RARITAN Indian Tribe lived. Although smaller they are all over, famous make. Magnesium should have given the game away. Mains feed and as I said Tee'd into a genset inter cooler. I have noted that the hot water is hotter from the intercooler than the thermostat mains setting, makes for scalding showers sometimes. Must have a higher degree setting on the wax stat.
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.

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JollyJack
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Re: Sacrifical anodes

Postby JollyJack » Sat Jul 18, 2015 7:44 pm

Never heard of it.
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