Vacuum Pump

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.
Nikelopez
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Vacuum Pump

Post by Nikelopez » Wed Jun 16, 2010 3:53 am

I would highly appreciate anyones opinion. I was looking for a vacuum pump and stumbled upon this model. But before I purchase I would your guy's opinion on this.
Its speed displacement of 14.1 CFM and an ultimate pressure of 1x10-4 Torr.

(Leybold D16 D16A Trivac Rotary Vane Dual Stage Mechanical Vacuum Pump)

http://www.pchemlabs.com/product.asp?pid=650

Any opion appreciated.

Thank You,
Nikelopez
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Tyler Christensen
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Re: Vacuum Pump

Post by Tyler Christensen » Wed Jun 16, 2010 3:55 am

It's a decent pump, although the price is far more than I'd suggest unless you have the money and want a pump that you know will come in good shape. You can get one on ebay for a tenth of that price although it probably won't come with a guarantee or warranty.

Keep in mind the 1e-4 torr rating won't actually be possible, that's just the rating when the inlet is capped off with a gauge, the moment you put a chamber on it you won't get that far or even approach it probably.

Nikelopez
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Re: Vacuum Pump

Post by Nikelopez » Wed Jun 16, 2010 4:03 am

Yes the price on the new one is quite a lot. However I just put this as an example because, i found the same model at an store near where I live selling it for 150. It looks to be in good form. I was just asking because I debating over whether or not it will help me and my partner get a vacuum great enough to achieve fusion.

Tyler Christensen
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Re: Vacuum Pump

Post by Tyler Christensen » Wed Jun 16, 2010 4:08 am

If in good condition it'll certainly get you to demo fusor pressures. Nearly everybody here (I'm not sure of anyone who uses a mechanical pump to get their actual fusor running) has a high vacuum pump stage after the mechanical pump, either diffusion or a turbo pump. Even if the mechanical can pull low enough for fusion, it'd do it so slowly you wouldn't realistically want to use it for it.

Nikelopez
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Re: Vacuum Pump

Post by Nikelopez » Wed Jun 16, 2010 4:12 am

I believe you sorta answered my next question. What I had in mind was using this mechancial pump along with a diffusion pump and a micromaze for actual fusion. But I'm not qutie sure if it'll be enough. But what from you recently stated I'm inferring it should do the job.

John Futter
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Re: Vacuum Pump

Post by John Futter » Wed Jun 16, 2010 4:22 am

NIKELOPEZ
These are very good pumps and has more than enough capacity for any fusion project.
Tyler is also correct a very good one running on our vac systems @ work gets around 3 by ten to the minus three millibar after a couple of weeks working as a backing pump on a 1000l/sec turbo pump.

So there is enough for demo mode, probably not enough for real fusion mode, but a diff or turbo pump will get you there just like that.
PS that pump is suitable for up to 500l/sec diff pumps or 1000l/sec turbo drag pumps.

Nikelopez
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Re: Vacuum Pump

Post by Nikelopez » Wed Jun 16, 2010 4:26 am

Thank You both,
Mr. Futter and Mr. Christensen

I think thats what ill end up doing. Using this pump for demo mode and for real fusion use it as well along with a diffusion pump and a micromaze.

John Futter
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Re: Vacuum Pump

Post by John Futter » Wed Jun 16, 2010 4:34 am

Nikelopez
you will not need the micromaze unless you want to recover some of the D2.
But I di recommend a foreline trap to keep the backing pump oil vapour out of the diff/ turbo.
yes the micromaze will do this as well but infinitely more difficult to clean.
Most forline traps use alumina beads that are not that expensive but if you are poor and have a furnace heating them to around 600-800 degrees celcius makes them as new

Tyler Christensen
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Re: Vacuum Pump

Post by Tyler Christensen » Wed Jun 16, 2010 4:37 am

I don't have any traps in my diffusion system anywhere and haven't had any problems with pretty heavy use over the last year. I think quality oils is sufficient to not need traps for fusion work, at least in my experience. Of course if you have the extra money for one, might as well stick it in.

Wilfried Heil
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Re: Vacuum Pump

Post by Wilfried Heil » Wed Jun 16, 2010 4:51 pm

These are great pumps. Try to get one of the newer "B" series like a Trivac D4B if possible. The older "A" series is just as good, but it may become difficult to find replacement parts for it later.

I would always use a foreline trap on the pump to prevent oil backstreaming into the chamber. You also need an oil mist filter on the exhaust of the pump. Plan for 2-3 oil changes with new and clean (dry) oil.

It is funny that a lot more of these pumps are available in the US than in Germany. They are used extensively in the semiconductor industry.

A smaller pump would also work, unless you plan to have a really big chamber. It makes a lot less noise and uses less electricity. The one that I use on the fusor is a Trivac D1.6B, with no additional turbo or diffusion pump needed. It reaches a base pressure of 3 mTorr in just a few minutes. I suppose that John's accelerator chamber is a lot bigger than ours.

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