Pfeiffer TMU 521 turbo pump repair kit question.

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Bob Reite
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Pfeiffer TMU 521 turbo pump repair kit question.

Post by Bob Reite »

Attached is a photo of the repair kit that arrived yesterday. I have not dismantled the turbo yet, so perhaps it it might become obvious at that time, but where does the cone shaped part in the blue envelope go? No instructions were suppled just a bill of materials.
bearing_pix.jpg
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
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Rich Gorski
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Re: Pfeiffer TMU 521 turbo pump repair kit question.

Post by Rich Gorski »

Bob,

I disassembled several Pfeiffer TPH050 pumps and replaced the lower bearing. If your TMU521 is anything like the 050 then the cone piece might fit on the end of the rotor shaft just below the lower bearing. The 050 has a similar cone shaped piece that has a thread on one end that screws onto the shaft end and a female Allen fitting on the other end to tighten it down. On the 050 the shaft inserts through a support washer like thing and the cone piece will tight down one the washer. This lifts the shaft off the magnetic bearing at the other end. In order to remove the cone on the 050 you have to lock down the rotor with a rod that is inserted through the frame and drops in a hole in the rotor. This stops the rotor from turning. Then the cone piece can be unscrewed at the other end with a allen wrench.

I don't know if that will help but that's my 2 cents. Good luck with your repair. I know these things are not obvious until you get into it. Even then its tricky work especially if you have to adjust something to get the rotor moving freely again with the new bearing. If your only installing a new bearing definitely do not pull the rotor out of the body. If you do the whole rotor/stator assembly will fall apart and it could be a nightmare to get it assembled again.

Rich G.
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Rich Gorski
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Re: Pfeiffer TMU 521 turbo pump repair kit question.

Post by Rich Gorski »

More... The cone shaped piece tightens the bearing down onto the support washer underneath. Once you remove the old cone shaped piece I believe you will be able to remove the old bearing. On the 050 once the cone shaped piece is off then you can pull (pry or pull with some force) the motor section and bearing off the shaft. That washer support is part of the motor section.

I haven't done this repair for a number of years and the procedure is slowly coming back to me.

Rich G.
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Rich Gorski
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Re: Pfeiffer TMU 521 turbo pump repair kit question.

Post by Rich Gorski »

Still more... When you remove the oil reservoir the cone shaped piece should be visible. The next step (on the 050) is to remove the 4 motor mount screws. Then lock down the rotor by inserting the rod into the frame and rotor on the high vacuum side and unscrew the cone piece. Then you should be able to pull off the motor section with the bearing. It required a little prying to separate the motor from the body before it would pop off. Installing the new bearing is kind of the reverse procedure.

Yea, its coming back to me.

Rich G.
richnormand
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Re: Pfeiffer TMU 521 turbo pump repair kit question.

Post by richnormand »

Is it screwed anti-clockwise and what size allen wrench?
Mine seems to be completely stuck and the allen wrench when inserted is a bit loose. Is it a special size? I do not want to ruin the thread.
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Rich Gorski
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Re: Pfeiffer TMU 521 turbo pump repair kit question.

Post by Rich Gorski »

Oh yes. this is important. The cone piece on the 050 has a reverse thread. So to loosen you have to rotate clockwise (opposite a normal thread). I can only tell you the allen size that fits the 050 but yours looks bigger so I won't venture a guess.

Rich G.
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Rich Gorski
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Re: Pfeiffer TMU 521 turbo pump repair kit question.

Post by Rich Gorski »

Pfeiffer is German made (I think) so I assume the allen is metric.
Matt_Gibson
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Re: Pfeiffer TMU 521 turbo pump repair kit question.

Post by Matt_Gibson »

How much was this kit? Alpine bearing gave me a quote of $135 for the bearing on my 071.

-Matt
Jerry Biehler
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Re: Pfeiffer TMU 521 turbo pump repair kit question.

Post by Jerry Biehler »

The cone picks up the oil off the wish and delivers it to the bearing. Its on pretty tight, I usually use an impact driver to knock kit loose. The cone also has a o-ring on its mating surface which may make it a bit sticky.
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Re: Pfeiffer TMU 521 turbo pump repair kit question.

Post by richnormand »

I did not think of using an impact driver. I'll look into that.
Also thanks for confirming it is a reverse thread.
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Dennis P Brown
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Re: Pfeiffer TMU 521 turbo pump repair kit question.

Post by Dennis P Brown »

Just an FYI: I have removed, repaired and re-installed the rotor blade assemblies. It is trivial as long as one removes them and stack them in order. In this manner, they are easy to replace (in some turbo's, they differ in style within the stack so order is critical in those situations.)

So, if you need to remove the main body, the stationary blades will need to be removed. Just stack them in order or lay them out in a manner that allows re-installing in proper sequence.

When re-installing, do one level at a time and spin the rotors and listen for any sound indicating contact. If so, readjust as needed - usually they interlock (between each set) and if not properly interconnected, this will cause contact between moving and stationary blades. If so, remove and test interlocking them to get an idea of how it is properly done. Then re-install.

If somehow any are bent, it is easy to bend them back flat. To check flatness, place them on a hard flat surface (a piece of flat glass plate is ideal) and confirm they are flat. If they are bowed, just gently bend them to make them flat again. The metal is very flexible and easy to bend.

Then re-installing the main body by carefully sliding the body down over the blades. Little to no contact should occur. Otherwise, a blade will move and make contact with a blade above it. Then unassemble and try again.

Always test the assembled system by spinning the blades. No sound at all should be heard.
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Bob Reite
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Re: Pfeiffer TMU 521 turbo pump repair kit question.

Post by Bob Reite »

The complete bearing rebuild kit, including the replacement oil cartridge, not pictured, set me back $850.00
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
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Bob Reite
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Re: Pfeiffer TMU 521 turbo pump repair kit question.

Post by Bob Reite »

I got the bearing changed out. On this model Pfeiffer, it's actually easier than doing it on some of the Leybold turbos that require dismantling all of the stators. A big thanks to all the contributors to this thread that gave me helpful advice.

So I'm now pumped down and have the quartz tubes on baking the chamber out. It's been at atmosphere for almost a month.

I will do a full write up with photos as a new message later on.
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
richnormand
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Re: Pfeiffer TMU 521 turbo pump repair kit question.

Post by richnormand »

Please do. That would be most useful.
Cheers.
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Richard Hull
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Re: Pfeiffer TMU 521 turbo pump repair kit question.

Post by Richard Hull »

Bob, I am glad you got it crankin' again. Repair of the mechanical part of a Turbo is a bold move.

Richard Hull
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Bob Reite
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Re: Pfeiffer TMU 521 turbo pump repair kit question.

Post by Bob Reite »

Here is the picture of the bad bearing and the oil cartridge. Note all the black from the bearing race deposited on the cartridge. The ceramic balls themselves probably did not wear nearly as much as the race.
bad_bearing.jpg
bad_bearing.jpg (89.55 KiB) Viewed 1108 times
The actual replacement process I will describe in a new topic.
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
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