Help me in my baby steps in the vacuum world.

Every fusor and fusion system seems to need a vacuum. This area is for detailed discussion of vacuum systems, materials, gauging, etc. related to fusor or fusion research.
John Futter
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Re: Help me in my baby steps in the vacuum world.

Post by John Futter » Wed Feb 10, 2021 4:26 am

try to find a manual for the pump

who made it??
it that a sight glass on the opposite side from the pulley?? the oil level should have been visible there

Cai Arcos
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Re: Help me in my baby steps in the vacuum world.

Post by Cai Arcos » Wed Feb 10, 2021 8:50 am

Richard, John:

The oil was a little bit over the half mark in the viewer. I still turned it on because it rotated freely when turned by hand.

Regarding the manual, or who made it: I have no idea!!
The only specification is a little placard that I attach below. I've spend quite some time searching for the model online (OD.10 or 0D.10) with no luck. The manufacturer is not specified anywhere. The motor that came with the thing has a placard from an italian motor making company. I strongly suspect the previous owner pulled this out of another vacuum pump, or changed the motor.
I asked the friend who gifted it to me and he also has no clue whatsoever.

Translation of the photo:
First row: Model
Second row: Current
Third row: Model number
Fourth row: Manufacturing date
Attachments
WhatsApp Image 2021-02-10 at 09.43.37.jpeg

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Maciek Szymanski
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Re: Help me in my baby steps in the vacuum world.

Post by Maciek Szymanski » Sun Feb 28, 2021 6:19 pm

Today I’ve changed oil in my BL8 rotary vane pump (the description of the vacuum system is in the separate topic: viewtopic.php?f=10&t=13708). I’ve used the cheap industrial grade VG68 class oil for milking machine pumps:

640F0BFC-3FF4-49F3-B815-8148B06F3897.jpeg

On the new oil I’ve reached pressure under 10 microns in the chamber (so probably even less on the pump flange) in 5 minutes. Personally I do not see any reason to use an expensive, laboratory grade oil in the second hand pump if such performance can be achieved without it.
“Begin at the beginning," the King said, very gravely, "and go on till you come to the end: then stop.” ― Lewis Carroll, Alice in Wonderland

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Mark Rowley
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Re: Help me in my baby steps in the vacuum world.

Post by Mark Rowley » Sun Feb 28, 2021 6:58 pm

Exactly what I’ve been harping about for ages Maciek. There’s some wild misperception that high grade expensive pump oil is required for the fusor hobby. We’re just not performing anything close to UHV work so it’s not necessary.

MR

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Maciek Szymanski
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Re: Help me in my baby steps in the vacuum world.

Post by Maciek Szymanski » Sun Feb 28, 2021 7:14 pm

In fact I won’t be surprised if those expensive oils are the exactly the same product as the mass produced industrial oils just repackaged and rebranded by Kurt Lesker, Varian or Alcatel...
“Begin at the beginning," the King said, very gravely, "and go on till you come to the end: then stop.” ― Lewis Carroll, Alice in Wonderland

Cai Arcos
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Re: Help me in my baby steps in the vacuum world.

Post by Cai Arcos » Sun Feb 28, 2021 9:58 pm

Oops!

I forgot to update this post! I changed the oil and let it run for a 50 minutes or so. Pressure never dropped any more than the previously reported. The oil came filthy once again. I redid the process once again with the exact results.

I have not had time to try once again with more oil, because life has gotten to me (family and university obligations). Furthermore the pump is at the place where my dad works (for triphasic power) so it makes everything more difficult.

To be honest, I have kind of given up on this pump. Two oil changes with no reduction of pressure whatsoever... Even if it is still filthy, a pressure of only around 1 Torr is still pathetic.

Guess I will be looking at some Chicom pumps. My main interest are not fusors, but radiation detectors, and most of the times you are only looking to eliminate oxygen out of the detector so that it's high electron attachment coefficient doesn't screw you over. For that around 50 microns should good enough.

In any case, thanks for all the help.

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Richard Hull
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Re: Help me in my baby steps in the vacuum world.

Post by Richard Hull » Mon Mar 01, 2021 1:04 am

Making GM detectors is a project I have been working on. I will update this effort in the radiation forum as I proceed with my effort. The upshot is that most GM detectors wind up back filled to between 50 and 100 torr with argon or neon and a quench agent. The quench agent is the sticking point. more on this as I go.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

John Futter
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Re: Help me in my baby steps in the vacuum world.

Post by John Futter » Mon Mar 01, 2021 4:18 am

Richard
When we were using Fris grid detectors at work (these are fancy Geiger tubes that position detect) we used Argon and a little 1-2% propane by volume as the quench agent

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