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Thread: Seal failure on an ALfa Laval Brew 80 centrifuge?

  1. #1
    Join Date
    Aug 2010
    Location
    Enterprise, Oregon
    Posts
    2,013

    Seal failure on an ALfa Laval Brew 80 centrifuge?

    We did our annual maintenance on our centrifuge about four months ago, and started seeing rising DO levels about two weeks ago. I tore into the machine, and, sure enough, the rotating seal was shot:

    Name:  2019-12-05 004 Centrifuge.jpg
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    We replaced the seals at our annual, so we got a little less than four months from this $1,500 part.

    It looks to me like the failure may have been due to heat. The ceramic mating surface of the seal appears to have spalled.

    I don't think we ever run the centrifuge with this seal dry, but that's what the damage looked like.

    Has anyone else seen this, and, if so, have you found a cause and a way to prevent this happening again?
    Timm Turrentine

    Brewerywright,
    Terminal Gravity Brewing,
    Enterprise. Oregon.

  2. #2
    Join Date
    Aug 2010
    Location
    Enterprise, Oregon
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    This was what the seal looked like at our annual:

    Name:  file.jpg
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    Timm Turrentine

    Brewerywright,
    Terminal Gravity Brewing,
    Enterprise. Oregon.

  3. #3
    Join Date
    Feb 2013
    Location
    Oklahoma City, OK
    Posts
    151
    Wow thats some serious wear at the seal. The most we've ever encountered is hairline cracks in the carbon seal, and we caught it pretty quick when we noticed DO starting to spike on consecutive batches.

    Is the solenoid that feeds water to the carbon seal during startup/standby/spindown working properly, or possibly there's a blockage in that line? When you did you annual service was it an intermediate or a major? Also, hows the top stationary part of the seal look? Same type of damage? Assuming you replaced both the stationary and the moving piece at the annual service?
    Last edited by TonyT; 12-07-2019 at 10:32 AM.

  4. #4
    Join Date
    Aug 2012
    Location
    Buena Vista, Colorado
    Posts
    12

    Destructive

    That looks like something happened in one event! We use our brew 80 on hot side (95C) and cold and have gotten slight pitting on top side but nothing like that! Are you sure your water pressure is good? No abnormal vibrations? Wish I could help more. Sorry.

  5. #5
    Join Date
    Nov 2009
    Location
    Moab, Utah
    Posts
    609

    Tech Support

    Quote Originally Posted by TGTimm View Post
    We did our annual maintenance on our centrifuge about four months ago, and started seeing rising DO levels about two weeks ago. I tore into the machine, and, sure enough, the rotating seal was shot:

    Name:  2019-12-05 004 Centrifuge.jpg
Views: 255
Size:  68.6 KB

    We replaced the seals at our annual, so we got a little less than four months from this $1,500 part.

    It looks to me like the failure may have been due to heat. The ceramic mating surface of the seal appears to have spalled.

    I don't think we ever run the centrifuge with this seal dry, but that's what the damage looked like.

    Has anyone else seen this, and, if so, have you found a cause and a way to prevent this happening again?
    I would be speaking to Tech support and also ask for Silicon Carbide to Carbon instead of ceramic.
    Warren Turner
    Industrial Engineering Technician
    HVACR-Electrical Systems Specialist
    Moab Brewery
    " No Cell Phone Zone."

  6. #6
    Join Date
    Aug 2010
    Location
    Enterprise, Oregon
    Posts
    2,013
    Tony--It was the intermediate service. We had Jason from AL come out to do it. We replaced both halves of the seal at that time. When I took it apart this time, the upper, stationary half looked fine.

    Eddyline--Wehave a pressure tank on the water input it insure we have constant water pressure. Seems to work just fine. No odd vibrations or anything.

    Warren--I've been in contact with Jason at AL. He's very helpful, but at this point it's a guessing game.

    Let's jut hope the new seal lasts a bit longer this time. We're reviewing start-up and shut-down procedures to see if there's any chance the seal is ever run dry.
    Timm Turrentine

    Brewerywright,
    Terminal Gravity Brewing,
    Enterprise. Oregon.

  7. #7
    Join Date
    Nov 2009
    Location
    Moab, Utah
    Posts
    609

    Thanks

    Quote Originally Posted by TGTimm View Post
    Tony--It was the intermediate service. We had Jason from AL come out to do it. We replaced both halves of the seal at that time. When I took it apart this time, the upper, stationary half looked fine.

    Eddyline--Wehave a pressure tank on the water input it insure we have constant water pressure. Seems to work just fine. No odd vibrations or anything.

    Warren--I've been in contact with Jason at AL. He's very helpful, but at this point it's a guessing game.

    Let's jut hope the new seal lasts a bit longer this time. We're reviewing start-up and shut-down procedures to see if there's any chance the seal is ever run dry.
    Timm, I 'd be interested to hear you findings. Also is it possible to monitor pressure or DP to take note if the condition is recurring? As in getting a baseline with a new seal and watching trend as to when you would be " sucking wind?"
    Warren Turner
    Industrial Engineering Technician
    HVACR-Electrical Systems Specialist
    Moab Brewery
    " No Cell Phone Zone."

  8. #8
    Join Date
    Feb 2013
    Location
    Oklahoma City, OK
    Posts
    151
    Quote Originally Posted by TGTimm View Post
    Tony--It was the intermediate service. We had Jason from AL come out to do it. We replaced both halves of the seal at that time. When I took it apart this time, the upper, stationary half looked fine.

    Eddyline--Wehave a pressure tank on the water input it insure we have constant water pressure. Seems to work just fine. No odd vibrations or anything.

    Warren--I've been in contact with Jason at AL. He's very helpful, but at this point it's a guessing game.

    Let's jut hope the new seal lasts a bit longer this time. We're reviewing start-up and shut-down procedures to see if there's any chance the seal is ever run dry.
    Interesting, definitely let us know what you end up discovering. Jason is great and has helped us out in the past on a few weird quirks with our machine. I would imagine if your bearings were starting to go you'd be seeing much more than this damage at the seal, but I don't know. I believe there are little screen or orifice filters at the water solenoid manifold, those are clear and clean?

  9. #9
    Join Date
    Aug 2010
    Location
    Enterprise, Oregon
    Posts
    2,013
    I watched as the machine finished spinning down yesterday, and noticed that the indicator lights on the various water solenoid valves were all off while the machine was still spinning. This would result in the seals running dry, which is consistent with the damage we've seen on the seals.

    I'm trying to discuss this with Jason, but he seems to be very busy lately. I may just bypass the solenoid valve for the seal wash/rinse line so it has continuous flow whenever the water to the machine is turned on.
    Timm Turrentine

    Brewerywright,
    Terminal Gravity Brewing,
    Enterprise. Oregon.

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