Update on a possible chamber

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Dennis P Brown
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Update on a possible chamber

Post by Dennis P Brown » Mon Nov 22, 2021 9:44 pm

Got a lead on a surplus 10 inch ID Cross with some flanges (3 of 4); better still, one is a window, and the other flange has a reduction fitting that matches my Turbo & gate valve connection - a simple 50 mm KF port (though this won't fit my diffusion pump but turbo's are cleaner just don't like depending on such an old device.) Luckily, my turbo/gate valve connection system has adapters for a TC, ion gauge, and gas inlet port above the gate valve so they don't need to be adapted to the chamber independently.

Will see if they accept my offer. Those 12 inch flanges aren't cheap or easy to find surplus; so this might not be the best approach on a cost bases even if they accept my offer since I'll need to locate another flange (though I might have a work around.) Having access to a machine shop, and experience using said machines makes this issue a lot easier. In the old days, middle school required machine shop training with metal as did my physics program in college; times have changed. Watched as one student nearly loss a finger (in a spray of blood and some tissue) to a shop design error in middle school shop class, so not sure if the change is all that bad.

Using my ugly approach for the remaining flange (lack there of), I should be able to adapt my existing high voltage feed thru to any flange of the correct size. See what happens when or if I get the system.
Last edited by Dennis P Brown on Tue Nov 23, 2021 12:16 am, edited 1 time in total.

Matt_Gibson
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Re: Update on a possible chamber

Post by Matt_Gibson » Tue Nov 23, 2021 12:15 am

Sounds like a huge volume to fill with deuterium, no? On the other hand, assuming plenty of deuterium available, this should allow for some really high voltages, right?

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Dennis P Brown
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Re: Update on a possible chamber

Post by Dennis P Brown » Tue Nov 23, 2021 12:18 am

Yeah, I have a lot of deuterium gas (having a "company" tax number had its advantages); a fairly mid size cylinder. Also, the gate valve will economize my gas use. This chamber is only about a factor of 50% greater volume than my old chamber.

I'm staying with 33 kV max. X-rays and me are kinda on different wavelengths ... ;)

Matt_Gibson
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Re: Update on a possible chamber

Post by Matt_Gibson » Tue Nov 23, 2021 3:15 pm

How much current can your psu pump out?

I could probably have deuterium shipped to my work address as we get SF6 gas shipped to us, but chose to go the more fun route and use heavy water and a PEM :-)

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Dennis P Brown
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Re: Update on a possible chamber

Post by Dennis P Brown » Tue Nov 23, 2021 7:08 pm

Anyone that creates their own deuterium using a cell I certainly take my hat off to. The people that do that certainly are working at a high level. I (before the clamp down on shipping gases) jumped on getting deuterium many years ago (it was still a pain but not if they considered you a company) and besides, back then, no one had developed an alternative so not a lot of choices there.

My power supply can hold 28 ma continuous (@32 kV) with no problem and well over 100 ma surge.

Well my offer for the chamber was accepted so I will head off after work and drive to VA (about an extra hour one way) to pick it up (way too heavy for me to want to pay shipping - however, not so sure I like the idea of picking up that amount of stainless steel, either - lol.)

Since my diffusion pump will not adapt to the new system, I will use my alternate system. I have a high vac system (Fore pump, oil trap, bellows valve, turbo and a sliding gate valve) but that is in moth balls since I gave up on my original approach (Accelerator) - however, I will have to get it working again since this chamber will readily mate to it. So, I'm glade I held on to it and didn't sell it. I kept it all together and ran it from time to time so it all works and is relatively clean. Can't speak for the new chamber, however. It looks rather new in pic's.

Hopefully, I'll have time to test all the components and check for leaks, outgassing problems and other standard vacuum/physical aspects this weekend. I both look forward to that fun - when things work - and also dread it for the inevitable problems that are going to occur. But that is one reason we all post here - to get help!

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Dennis P Brown
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Re: Update on a possible chamber

Post by Dennis P Brown » Tue Nov 23, 2021 11:32 pm

The chamber is not as heavy or as large as I thought - they are eight inch flanges/openings; yes, the cross is diagonally 10 inches on the inside. The interior volume is still rather large. So, actually I am glad about my mistake - a lot easier to lift and handle; that is a relief. It was used (apparently) to store samples under vacuum - it had shelves still in it (I removed them.) Extremely clean. I should, after the holiday, be able to pump it down to get a feel for its vacuum capabilities. The O-rings and their retainer mounts, as well as all mating surfaces, look pristine (rather critical - I'd never want to dress those surfaces). Very relieved about that. The view port is large, and rather thin glass - I'd worry about that long term but for a few tests with plasma, it should be fine. I'll look for some fine wire mess at the hardware store to cover the inside to protect it from the plasma in the future.

This project is moving faster again so surely a road block is bound to occur - opiumism, the false hope that reality isn't really reality; the real story of fusion research. ;)
Last edited by Dennis P Brown on Wed Nov 24, 2021 5:43 pm, edited 1 time in total.

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Dennis P Brown
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Re: Update on a possible chamber

Post by Dennis P Brown » Wed Nov 24, 2021 5:07 pm

Well, had some time today so I installed the chamber onto my high vacuum station. Have no top flange system that seals yet so can't pull a vacuum. Have a possible methodology but that will take some mod's that I may or may not get around to today. Rather busy. But it is getting there. Need to reinstall my dry air system to the turbo; not that that is essential but will enable me to slow/stop the turbo with the least issues for the bearings.

I have a large, rectangular shaped lead shield mounted in a wood frame (1.5' x 3'); I will install this as a "door" that will stand between me and the fusor as extra precaution. Since that glass window is too thin to be safe I will rotate the chamber 90 degree's so that isn't facing me. I will use a mirror so I can see the plasma for control. The walls of this chamber are much thinner than my old fusor chamber so X-rays might be an issue.
Attachments
20211124_121523.jpg
(Above) Future fusor chamber (a std ruler for size comparison)
20211124_120050.jpg
Chamber mated to the High vacuum system w/gauges

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Richard Hull
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Re: Update on a possible chamber

Post by Richard Hull » Wed Nov 24, 2021 6:01 pm

I see your chamber is ISO flanged. I like ISO flanges. They are easy to remove and install, especially in the case of a fusion main chamber. This works nice for systems that will not suffer extreme excursions in temperature. Conflats have been the norm here solely due to their surplus availability and the profusion of images on this site where they are seen used by newbies.

You have a nice roll-around system there. Good design effort.

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
Retired now...Doing only what I want and not what I should...every day is a saturday.

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Dennis P Brown
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Re: Update on a possible chamber

Post by Dennis P Brown » Wed Nov 24, 2021 6:17 pm

Thank you, Richard! Surplus is hit or miss but I certainly prefer ISO when able (the company I deal with has gems from time to time.) Replacing copper gaskets seems like a pain.

I designed that bench for a shielded accelerator so wanted it to be mobile to get it out of the way (it had a few hundred pounds of shielding so wheels were essential.) Realized this old and unused system would be useful for my new (and heavier) fusor - having easy access to all sides by moving the whole system also makes life easier, I will say.

The power supply is overly large but I like room to install stuff and not have HV wires & components near other parts. It is a bit heavy but I intend to place it on the table top so I can adjust the voltage without issue; I recall only too well how touchy a fusor is at its operating pressure. Fine adjustment of the deuterium control valve and variac simultaneously while observing the plasma is critical for good fusor operation - as is keeping an eye on the amp gauge so as not to over drive the x-former.

I'll add my deuterium supply and dry air system later this weekend; maybe even figure out how to install the HV access/flange (likely a temporary kludge) - that is the sole issue currently holding up that step.

Update: Kludge certainly not viable - lol; understatement. Have to consider another method.

Matt_Gibson
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Re: Update on a possible chamber

Post by Matt_Gibson » Thu Nov 25, 2021 7:00 pm

Looking good, can’t wait to see some plasma!

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