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Seal failure on an ALfa Laval Brew 80 centrifuge?

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  • 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:

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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
    This was what the seal looked like at our annual:

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    Timm Turrentine

    Brewerywright,
    Terminal Gravity Brewing,
    Enterprise. Oregon.

    Comment


    • #3
      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, 11:32 AM.

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      • #4
        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.

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        • #5
          Tech Support

          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:

          [ATTACH]64615[/ATTACH]

          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
          The Thought Police are Attempting to Suppress Free Speech and Sugar coat everything. This is both Cowardice and Treason given to their own kind.

          Comment


          • #6
            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.

            Comment


            • #7
              Thanks

              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
              The Thought Police are Attempting to Suppress Free Speech and Sugar coat everything. This is both Cowardice and Treason given to their own kind.

              Comment


              • #8
                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?

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                • #9
                  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.

                  Comment


                  • #10
                    Well, it's been about three months since we last replaced the top seals of the centrifuge.

                    Guess what?

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                    Yep. Another one. The brewers were rinsing the centrifuge in prep for a transfer to bright tank. The centrifuge would not build pressure, and there was a lot of air in the sight glass on the output of the bowl.

                    Don't tell me that we are the only ones seeing this problem with the AL Brew 80. It seems to be a programming flaw. When the centrifuge is spinning down, the valve(s) that supply water to wash the seals is (are) turned off. Jason told me the valves are only open when product is flowing through the flowmeter, so the seal is dry during the entire spin-down and, I guess, spin-up phase.

                    $3k for three months of operation is pretty steep.
                    Last edited by TGTimm; 03-23-2020, 01:58 PM.
                    Timm Turrentine

                    Brewerywright,
                    Terminal Gravity Brewing,
                    Enterprise. Oregon.

                    Comment


                    • #11
                      Originally posted by TGTimm View Post
                      Don't tell me that we are the only ones seeing this problem with the AL Brew 80. It seems to be a programming flaw. When the centrifuge is spinning down, the valve(s) that supply water to wash the seals is (are) turned off. Jason told me the valves are only open when product is flowing through the flowmeter, so the seal is dry during the entire spin-down and, I guess, spin-up phase.
                      No, this is false. Whenever the machine is in spin-up, spin-down or standby there is a solenoid that sends water to a nozzle inside the top of the bowl hood which is aimed directly at the carbon seal. The water lubricates the seal and prevents this exact type of damage from happening. Sounds like there is something off with your program for sure, as that seal should NEVER run dry. I have a direct line to another Alfa Laval tech that has helped us before if you're not getting anywhere. Send me a direct message, happy to help. We've been inside and out, up and down our Brew80, maybe it's actually an easy fix. I'll do some looking tonight at ours.
                      Last edited by TonyT; 03-23-2020, 02:51 PM.

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