is this vacuum pump alone enough to use with a fuser?

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Lazyjohn76
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is this vacuum pump alone enough to use with a fuser?

Post by Lazyjohn76 »

is this vacuum pump alone enough to use with a fuser?
Vacuum Pump: https://hvactools.co.nz/product/economi ... 2SEALw_wcB

thanks.
JoeBallantyne
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Re: is this vacuum pump alone enough to use with a fuser?

Post by JoeBallantyne »

No. Its ultimate pressure is 15 microns. You need a pump that can get down to 1-2 microns or less.

Some Welch 2 stage mechanical pumps that are in outstanding condition can do that.

Most folks use mechanical pumps as a backing pump for either a diffusion or a turbo pump, in that situation a mechanical pump that gets down to 15 microns is just fine. Since the turbo or diffusion pump will pull down to much less than a micron. (10e-3 torr)

Joe.
Liam_Bastnagel
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Re: is this vacuum pump alone enough to use with a fuser?

Post by Liam_Bastnagel »

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Richard Hull
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Re: is this vacuum pump alone enough to use with a fuser?

Post by Richard Hull »

Any brand new two stage pump should do. However we are fighting the old versus the new. In the old days pump manufacturers listed bottom vacuums of 0.1 microns as there bottom point. This was never met! A pump that can truly hit 15 microns will do for either a demo or real fusor.

The issue is.... Will it truly hit 15 microns? Have the manufacturers awakened to truth in advertising?

Any pump you buy must state that it is a two stage pump!

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
Andrew Seltzman
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Re: is this vacuum pump alone enough to use with a fuser?

Post by Andrew Seltzman »

One thing to note:
Air conditioning service pumps are NOT designed for continuous operation (even if they "claim" to be in the amazon description); they will often overheat and fail if operated continuously. They likely would be OK for short ~15-30min demos. The 2 stage pumps max out at around 15mTorr even if they claim better (I tested a few for plasma outreach demos) though this is certainly enough for a glow discharge in a demo fusor.

Scientific vacuum pumps are designed for continuous operation (months or more), and typically can get down into the 5-10mTorr range in a connected vacuum chamber.
Andrew Seltzman
www.rtftechnologies.org
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Richard Hull
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Re: is this vacuum pump alone enough to use with a fuser?

Post by Richard Hull »

Vacuum technology is a learning process. At times, it can be costly when mistakes are made, especially at the beginner level.

Top grade refrigeration service pumps can run for a few hours without overheating to destruction.
Old belt drive pumps are designed for 24-7 operation. They have much larger cast bodies per CFM capacity to absorb and dissipate heat
All pumps and their motors get hot, often, very hot.
This is normal...
For any given chamber size, the same work must be done continuously to take it to a specific vacuum level and hold it there. Fusors, (demo or real), demand that the mechanical, foreline pump run continuously. Rarely are such runs conducted for more than two hours.
The waste heat from doing this winds up in the vacuum pump and the motor driving it.

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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Bob Reite
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Re: is this vacuum pump alone enough to use with a fuser?

Post by Bob Reite »

Some turbo pumped systems can run with intermittent backing. That is the roughing pump only comes on as needed. On my system the current drain of the turbo is monitored and when it gets too high, the backing pump starts up. This saves wear on the pump as well as my electric bill, since I leave my system pumped down all the time (albeit on "standby" mode to a level around 5 microns).
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
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