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  • Results 1 to 10 of 10

    Thread: Mechanical Seal

    1. #1
      Huysy's Avatar
      Huysy is offline Senior Member
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      Mechanical Seal

      So my diy RDF decided to flake out about a week ago after 4 months of flawless performance. I used timing belts and sprockets to rotate the drum instead of sprockets and chains that others have used.
      What once worked great when new is now having problems moving the drum. The belt is slipping due to, I assume, wear or stretching of the belt and just gunk and debris causing increased friction.
      I almost purchased wider belts and sprockets to get a little more grip on the drum but then decided to go direct drive. I researched for days about mechanical seals and how they worked, but found nothing that I could
      just drop into my RDF easily. So this is my attempt at fabricating a motor mount with an integrated seal ring.

      Here is the seal ring I fabricated out of pvc.

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      Here is the ring with the seal seat inserted.

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      Here is the cut I made on the RDF to accept the motor mount.

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      Here is the motor mount with motor attached. I used PL roofing adhesive to seal the mount. In front of the motor is an aluminum coupler to mate the 8mm motor shaft to the 12mm drum shaft.

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      And finally, here is the mechanical seal on the inside of the RDF. I used a shaft collar to keep tension on the spring so that the two mating surfaces always has good contact. So far so good. No leaks!

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    2. #2
      kimini is offline Senior Member
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      So you couldn't (or didn't want to) run the drum at less than half full, and running no seal at all?

      I wondering about the timing belt approach, thinking it might have worked better than my setup, but the chain and sprocket fiasco kind of soured me on belts and chains in general.
      Last edited by kimini; 07-10-2017 at 08:45 PM.
      Author of Midlana, Build this High Performance Mid-engine Sports Car. http://midlana.com/stuff/book

    3. #3
      Huysy's Avatar
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      My drum is only 15" wide by 12" deep. I need all the surface area I can get. There is no way I could run it half full and flow 3500-4000 gph through it. I am sure a wider belt would have worked for me, but it's nice to remove a point of failure
      from the RDF.

    4. #4
      kimini is offline Senior Member
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      Did you use the pump seal which you (I think it was you) recommended in another thread? I bought that one and couldn't use it because the shaft I used has a keyway.
      Last edited by kimini; 07-10-2017 at 08:48 PM.
      Author of Midlana, Build this High Performance Mid-engine Sports Car. http://midlana.com/stuff/book

    5. #5
      Huysy's Avatar
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      I wasn't the one who recommended it, but I remember seeing a recent thread about it. The one I used was the same type. Comes in 2 parts...a seat and the spring loaded rotating face.

      I was going to recommend a seal in one of your threads but then I saw your keyed shaft LOL. If your shaft was only keyed at the end, then this type of seal could work for you too.

    6. #6
      jasonir129 is offline Senior Member
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      bump

      how's your direct drive setup holding up? Any drips? Are you using one of the buna cup shaft seals previously posted? Planning on converting my BE this winter and evaluating the options, direct drive like this is my top contender.

      Is the seal itself loaded/bearing the weight of the rdf axle?

    7. #7
      Huysy's Avatar
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      The seal is holding up great. No leaks. Here is the seal that I used since my shaft is 12mm in diameter: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

      The description does not specify what the elastomer is...probably buna. This type of seal is not made to handle a load, but you could easily add a stainless flange bearing outside the RDF to support the weight of the drum.

      I have no bearing on mine. The shaft sits in a hole drilled into a thick pvc support brace that horizontally spans the width of the rdf. This support brace as well as the motor bearing handle the load.

    8. #8
      Riftlake is offline Senior Member
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      How did you attach the shaft to the drum? Is that shaft you used keyed on the end with a hub?

    9. #9
      Huysy's Avatar
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      I used what I had on hand. I re-used one of the sprockets and essentially created a hub. My shaft is not keyed, but I did tap the sprocket for an extra screw set for more holding power. The sprocket is attached to the drum with 2 stainless bolts. Sprocket is made of aluminum and is corroding. I plan to replace it one of these days with a proper stainless hub.

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    10. #10
      Riftlake is offline Senior Member
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      I found this 12mm stainless keyed hub you might be interested in: https://www.robotshop.com/en/12mm-se...w-key-hub.html

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