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Registered Member #1438
Joined: Sat Apr 12 2008, 12:57AM
Location: Canada
Posts: 218
I've been searching on eBay and stumbled on a vacuum pump which has a ultimate vacuum pressure of 5 Pa (~0.037 Torr). And it only costs US $69.90 USD without shipping and $99.85 USD with international shipping.
Specification:
Voltage /Frequency: 110V/60HZ Flow Rate: 1.8CFM ( 50L/MIN ) Ultimate Vacuum: 5 Pa (0.05mbar) RPM: 1400RPM Power: 1/4HP Inlet Port: 1/4" Flare & 3/8" Flare Oil Capacity: 320 ml Overall dimension: 10 1/2" x 4 1/2" x 8 1/2" Weight: 5.3kg
Is the information possibly be misleading? Or do you really think it would pump down to less than 100 microns?
A follow up question which is more related to another category in the forum is that is the vacuum pressure range needed for a fusor.
I've checked some forums including this one and Farnsworth's fusor patent and found that there are some conflicting reports on the vacuum needed to achieve electrostatic confinement fusion.
Some reports on different forums and fusor fan sites say that it can be as high as 70-100 microns.
Fabio claims that fusion only occurs at 1 micron or less and 150-80 microns is needed for the electrostatic confinement.
Farnsworth Fusor patent claims to have run the fusor at 1 micron.
From the looks of it, it does seem that 1 micron is needed but is the fusion by electrostatic confinement even slightly operational at the 70-100 micron range?
Or would it be necessary to have a secondary pump like an oil diffusion pump or a turbomolecular pump connected to this 5 Pa pump to achieve fusor quality vacuum?
Registered Member #1438
Joined: Sat Apr 12 2008, 12:57AM
Location: Canada
Posts: 218
Ash Small wrote ...
Firstly, the quoted figure is what you'd expect if you just connect a guage to the inlet, with no plumbing or chamber.
Secondly, I seem to remember that you need ~10^-5 for a fusor. Remember also, that you need to 'purge' the chamber before you backfill with deuterium.
What they call 'demo fusors' will work at higher pressures (this pump may be ideal for that).
You WILL need either a diff pump or turbo pump as well for fusion.
Hmm well that's a bit of a let down. Can't figure out for the life of me how some people like plazmatron is able to get diffusion pumps for only £5.5. Seems like the average prices for these diffusion pumps range anywhere from a $100 to over a $1000.
Registered Member #3414
Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245
Dragon64 wrote ...
Hmm well that's a bit of a let down. Can't figure out for the life of me how some people like plazmatron is able to get diffusion pumps for only £5.5. Seems like the average prices for these diffusion pumps range anywhere from a $100 to over a $1000.
I paid £150 for a brand new, old stock, one still in the original box, never used. I also picked up another for under £50.
You should easily be able to find one for under $100 if you keep watching E-bay for a while.
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Vacuum Pump - Too good to be true?
