Is the Leybold TRIVAC B series capable of 10^-3 or 10^-4 mbar?

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Luca Aldridge
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Is the Leybold TRIVAC B series capable of 10^-3 or 10^-4 mbar?

Post by Luca Aldridge »

Hi, just a quick question - on the product manual

https://www.leyboldproducts.com/media/p ... 021_EN.pdf
Page 7/40

It says it’s capable of 10^-4 mbar.


However, on the shop it says it’s 2*10^-3 mbar.

https://www.leyboldproducts.com/product ... c-b/pumps/
Follow any of the links.


What one is it?
Thanks in advance.
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Dennis P Brown
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Re: Is the Leybold TRIVAC B series capable of 10^-3 or 10^-4 mbar?

Post by Dennis P Brown »

Vacuum pump companies have their own methods to measure the ultimate pressure a pump can achieve. All such values can generally not be achieved in real world circumstances. The former number is extremely unlikely for a two stage oil based pump. The later is more realistic but is the pump working only on a vacuum gauge detector directly. Really these exact values are not important relative to fusors since they also require a high vacuum pump as well - either a turbo or diffusion pump meaning a 10^-3 mbar pump will work extremely well for a fusor. For other applications these numbers might matter.
Luca Aldridge
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Re: Is the Leybold TRIVAC B series capable of 10^-3 or 10^-4 mbar?

Post by Luca Aldridge »

I was already aware that I would need a turbo pump, however the same company offers a range of them that only start working at pressures below 10^-4 bar, so buying a 10^-3 bar rough pump would be useless
I’m now looking at another company that offers ones that start working at 10^-2 bar which will be sufficient
Thanks for replying
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Liam David
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Re: Is the Leybold TRIVAC B series capable of 10^-3 or 10^-4 mbar?

Post by Liam David »

Any dual-stage rotary pump from a reputable manufacturer such as Leybold will back any turbo/diff pump. In new condition they can pump to single-digit microns (~1e-3 mbar). For a diff pump, you probably want below 0.1 mbar, while depending on the type of turbo (i.e. turbo, molecular drag, or compound) the minimum is between 0.1 and 1 mbar. Shoot, most people here would be happy to hit 1e-2 mbar with their backing pump before firing up the diff/turbo. I think you're trying to split hairs (I think you're also mixing up bars with millibars).
Luca Aldridge
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Re: Is the Leybold TRIVAC B series capable of 10^-3 or 10^-4 mbar?

Post by Luca Aldridge »

Liam

Yes I was mixing up mbar and bar.

If the pump can get to 1 micron as it say it can, do I need another pump as if I repressurise with D2 back to 5 microns, I have a 5 micron pressure environment with 80% D2 and 20% air. Surely that’s adequate to do fusion with?

Just asking as I don’t want to spend money on a UHV turbo/diff pump that I don’t need. Those are expensive!!

Luca
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Liam David
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Re: Is the Leybold TRIVAC B series capable of 10^-3 or 10^-4 mbar?

Post by Liam David »

You can use just a backing pump, although the neutron rate will be reduced. It must be able to pump in the low single digits, meaning used pumps will be a gamble. If you use a smaller chamber, the operating pressure will be higher and so the purity for a given base pressure will be better.

Depending on your budget, there are a couple of good deals on turbos on ebay. All I can say is patience is key here. The absolute lowest you might expect to get an operational system is ~$500.
Luca Aldridge
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Re: Is the Leybold TRIVAC B series capable of 10^-3 or 10^-4 mbar?

Post by Luca Aldridge »

I think then that I'll just use a backing pump, and if budget allows a turbo pump

$500 is better than I was expecting - I was preparing for 2.5K
Although I can't find any companies offering new turbos for that much.

My chamber is a 20*20cm cylinder.
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Dennis P Brown
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Re: Is the Leybold TRIVAC B series capable of 10^-3 or 10^-4 mbar?

Post by Dennis P Brown »

New turbo's run $2 k or more for the smallest units (no controller.) Diffusion pumps and a good gate valve (manual) can usually be had for much less.
Luca Aldridge
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Re: Is the Leybold TRIVAC B series capable of 10^-3 or 10^-4 mbar?

Post by Luca Aldridge »

Could you possibly link a source? The ones I've tried (Leybols, Edwards, Pfeiffer) all are approx 4k or more
I'd want a whole system, meaning all PSUs, controllers, valves and both pumps to be at most $4-5k
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Dennis P Brown
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Re: Is the Leybold TRIVAC B series capable of 10^-3 or 10^-4 mbar?

Post by Dennis P Brown »

I've seen turbo's and controllers for around those costs in the recent past; however, of late, prices have risen due to certain policies made a few years ago. I don't have time to search for them but do an ebay search and many units are available. If none are in the right price range, wait a few days and try again. Kinda an important learning tool if you intend to buy equipment. Yes, new turbo's are sold on ebay. Just never buy anything that the seller will not accept a return for full refund.

Sorry - complete systems are expensive: pumps, valves, lines, relays, controller. Companies sell those systems but can't give a price but under $5k, not gonna happen.
Luca Aldridge
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Re: Is the Leybold TRIVAC B series capable of 10^-3 or 10^-4 mbar?

Post by Luca Aldridge »

That's annoying but hopefully I can make my own system for under 5k if I use eBay
Yes, I 100% wouldn't do that if there was a danger of losing money.
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Liam David
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Re: Is the Leybold TRIVAC B series capable of 10^-3 or 10^-4 mbar?

Post by Liam David »

I did not mean to inspire false hope. I've gotten 3 functional systems (turbo+controller+cables) each for under $500 over the last 8-ish years. These kinds of deals are exceedingly rare and I haven't seen any in several years, although I haven't been looking very hard since I don't need more. The multi-year waiting game is not fun, I'll be the first to admit.
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Re: Is the Leybold TRIVAC B series capable of 10^-3 or 10^-4 mbar?

Post by Richard Hull »

All things come to he who waits.... This old saw is true provided you wait with an eagle's eye on your needs. I always lusted after the fine gas control of a Sapphire leak but I limped along with a needle valve.

Finally, in 2019 after 20 years of fusion, I found the $900 surplus leak for $50 and leaped on it. Like so many instances, I came across and purchased a second one a year later. All those vacant years and then two leaks in two years! I added one to my fusor V and enjoy the smooth and sweet control it affords. Time is always on your side it you can get by with a bit less and move forward in a stepped process. This is provided your interest remains constant.

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
Luca Aldridge
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Re: Is the Leybold TRIVAC B series capable of 10^-3 or 10^-4 mbar?

Post by Luca Aldridge »

My interest will always be there, but as for right now I have one shot in terms of money and I need to get it right. I won't be able to get new things for at least ten or fifteen years, hence my wanting of a bulletproof system
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