EO2 Diffusion Pump Yae or Nae?

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Nick Babusis
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Real name: Nick Babusis

EO2 Diffusion Pump Yae or Nae?

Post by Nick Babusis »

I am considering buying this diffusion pump and want to make sure I'm not overlooking any major issues before I spend my lab assistant pittance on it:
https://www.ebay.com/itm/155266407831?h ... SwdAJjeVvx
It seems to be a good price as the only pumps I can find listed for cheaper have unusual/no flanges or no datasheet. I had to get the datasheet for this model directly from Edwards (should I post it here somewhere?). Seller does not list anything about the jet stack or heater continuity, but states "in good working condition".

I plan to use ECO-704 oil and a 5cfm 2-stage backing pump I already have (provided it still works). The datasheet lists 75ml oil charge, 170 l/s pumping speed, 400W heater, and 3.6 cfm minimum backing pump displacement.

Is there anything I overlooked?
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Aidan_Roy
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Re: EO2 Diffusion Pump Yae or Nae?

Post by Aidan_Roy »

Hi Nick,

If you can work those I/O flanges to be usable on your set up and get it for a good price, I say YAE. I use that pump on my 2.5” CF cross set up as well as my 6” CF cylinder that is currently in the works. Mine came with a cold trap that converted their proprietary flange to ISO60 and it works like a charm. Heats up a bit slow if you are running on 120v but I can bottom out my gauges at 1 x 10e-6 torr in a matter of seconds once its going, and she only takes a little bit of oil. Make sure the baffles are in good shape and that the water line is clear before you run, if you decide to buy it. I also have full manuals from Edwards for the original E02 model, as well as the slightly newer E02K if youd like to see em’. Good luck.

Aidan Roy
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Richard Hull
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Re: EO2 Diffusion Pump Yae or Nae?

Post by Richard Hull »

i think this is air cooled. I did not see any water lines. It appears as more of a museum piece. I love the inlet spigot!


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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Emma Black
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Re: EO2 Diffusion Pump Yae or Nae?

Post by Emma Black »

Hey Nick, welcome!

My quick tip on firing up long stored diff pumps, is that you may need to dry out the element before use. Mine had been sitting for years and would trip out the house ground fault, the element had absorbed water. A bake out in the oven or run at lower voltage to start with should avoid this issue.
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Dennis P Brown
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Re: EO2 Diffusion Pump Yae or Nae?

Post by Dennis P Brown »

I retired my DP pump a few years ago but regret doing that - a turbo creates all sorts of new issues (electric noise is the worse.) That pump looks in very good condition. You might need to baffle the unit to prevent oil back streaming during operation (I simply added a copper plate so there was no direct line of sight into my chamber.) An elbow bend works just as well. Ditto if you use a butterfly value to control the flow between the DP and chamber (extremely useful in saving deuterium.)
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Rich Feldman
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Re: EO2 Diffusion Pump Yae or Nae?

Post by Rich Feldman »

Looks good. It won't work sideways (as pictured) or in microgravity. :)
All models are wrong; some models are useful. -- George Box
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