Possible "cheaper" system...

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.
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JamesBroussard
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Possible "cheaper" system...

Post by JamesBroussard »

Well this may sound stupid and hope it hasn't been covered before but... before i get into it seems like i appear here every few months/year haha. I was going to start a new project about a year ago but got distracted with other projects, anyways...

On to it, I have my chamber still and happened to seal it recently with copper flanges (plan on making a newer one soon), lack of suitable vacuum system for fusion pressures led me to come across a website were i noticed a post about "Converting a refrigerator compressor for cheap vacuum pump", mostly used for vacuum bagging and such, one guy claimed to achieve around 10 millitor, seems it could be well enough to back a diff pump.

A few problems seem to be obviously prevalent in the form of cooling/oil retention as well flushing the CFC/freon (whatever they use)... anyways while i search for a decently priced vacuum pump(might hit cindy up from LDS for this) ill see what i can do with a few put in series and a diff pump for the time being.

also found this cool page on constructing a TC gauge

http://www.belljar.net/tcgauge.htm
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Carl Willis
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Re: Possible "cheaper" system...

Post by Carl Willis »

Hi James,

Use of refrigerator compressors as makeshift vacuum pumps was a more common occurrence in the days of mercury diffusion pumps. The vacuum of a few torr produced by one (if lucky) or two of these compressors in series could adequately back a mercury diff pump on a small, slow high-vacuum apparatus. This is not true of today's oil diff pumps, which really need 0.1 torr or less. Thus one of the main applications of refrigerator compressors in amateur vacuum service has gone extinct. In fact, I don't think I've seen a credible recent report of compressors being used, and I have no idea how today's compressors might fare if they were rigged up like their ancestors from sixty years ago. (I would be surprised if they worked as well--indeed I'd be surprised if they could handle continuous service without burning up.)

Didn't you have a Welch 1410 on hand at one time?

-Carl
Carl Willis
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JamesBroussard
Posts: 28
Joined: Fri Sep 14, 2007 4:06 pm
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Re: Possible "cheaper" system...

Post by JamesBroussard »

Hey Carl,

yeah this seems unfortunately true,.. ill mess around with it alil to see what can be had, at least it might be useful for something or other (maybe could be used for cooling? think iv seen a pic somewhere that illustrated something with two pistons, maybe it was a pulsed tube cryocooler" not sure but would be cool if it had some usefulness other than a large paper weight).
hah you must have a good memory, problem is that i borrowed the pump from my high school physics lab for a few months and now in college i had to give it back (contemplated saying i lost it but regardless i'm vacuum less) maybe i could borrow it forever without asking... sure they never use it with the impressive dust they collected...

I recently used a dremel tool to cut a slight grove in the bottom and top half's of the fusor flange thus applying a copper ring in the bottom grove and topped with a flattened/welded end to end copper tube ring on top of that to get rid of the silicon flange which, i'm sure was the source of my leaks.

sigh... wish i had that pump to test it now :|
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