Final Design

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bk8509a
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Final Design

Post by bk8509a »

Welp, here it is. After quite a bit of time my whole team has our design worked out, complete with 6" view port! Parts will be ordered in the coming week and assembled. Some holes/tapping will be needed but it shouldn't be too tedious. Tell me what you think.

If you're curious I can send you the budget. Also, just picked up a pump and an oil mist filter for 202 total on ebay. Things are starting up.

-BK
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Tyler Christensen
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Re: Final Design

Post by Tyler Christensen »

I would suggest not putting your pressure transducer on the same tee as your vacuum pump, I have found that putting gauges on the same branch-out as either the deuterium input or the pump output can cause meaningless results due to imbalanced pressure in that area due to either the higher or lower pressure of the chamber inlet or outlet respectively.
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Doug Coulter
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Re: Final Design

Post by Doug Coulter »

Looking good indeed! If your experience parallels ours, I think you are going to find that there's a certain optimum ratio of inner grid size to outer electrode, and you outer is on the small side for the inner size. Paschen's law will also mean that with the smaller outer size you'll need either more pressure or more volts than the guys running 6", though that size isn't magic either (we have run from 4" to 14" for that number and have made them all work, some better than others). I am just now getting ready to put some details of tests we did on these parameters on my site, I'll link back here when I do.

This is not to tell you to change anything, just things to look for when you run.

Best of luck, this looks like a winner.
Why guess when you can know? Measure!
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Steven Sesselmann
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Re: Final Design

Post by Steven Sesselmann »

Brian,

Nice drawing....

If I were you, I would forget the word "Final" in connection with Fusor design...

Before you know it you will be working on MK5 and your first design will be somewhere in the junk box, and only good for spare parts

Steven
http://www.gammaspectacular.com - Gamma Spectrometry Systems
https://www.researchgate.net/profile/Steven_Sesselmann - Various papers and patents on RG
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Doug Coulter
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Re: Final Design

Post by Doug Coulter »

Good point Steven, I'd second that one. The glory of science is to make progress after all, and that implies that what you know now is incomplete, so "final" is a really strong word to put on things.

This design does look like that was in mind at the time though, pretty easy to change things with all that nice access to the innards. Good show!
Why guess when you can know? Measure!
Starfire
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Re: Final Design

Post by Starfire »

That sounds like experience. Steven.
myID
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Re: Final Design

Post by myID »

Hi-

I also agree- it will grow and you will have a lot of changes- BUT- looks like a great (i.e. flexible and modular) setup to start with.
I also made the experience Tyler made- due to different "flow" in high vacuum it is important to locate the pressure sensor "looking in the chamber" and not in the up- or downstream connection.
And- you will have to feed your D2 somewhere
What CAD software did you use? Do you have a library with vacuum parts? That would be handy! Nice drawing!

Greets
Roman
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Carl Willis
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Re: Final Design

Post by Carl Willis »

Hi Brian,

Looks very nice.

I advise caution on the large viewport. While suitable for eye candy, it's an expensive accident waiting to happen (due to electron heating). Windows charge up during operation and the flashover can be quite disconcerting.

-Carl
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Doug Coulter
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Re: Final Design

Post by Doug Coulter »

Here I can't live without the eye candy, so I use a sacrificial window in front of the viewport glass, inside the tank. I use the relatively conductive pyrex (orders of magnitude more conductive than quartz) clipped into the flange stub for that, and after awhile a little sputtering onto it makes it even more conductive. This piece you can take out and dunk in acid when it gets covered with sputtered metal as well, something you'd not want to do with an expensive viewport. At any rate, this protects the expensive piece and brings charge accumulation troubles to a halt. And you get to keep the eye candy.

Here is a link to the piece sitting on the table:

http://www.coultersmithing.com/Runs/FusionClub.html

I don't have a good link just now to the thing in place just behind my 6" door/window, but that's where it lives and it solves all that just fine. I am in the process of updating that site, so stay tuned.
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DaveC
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Re: Final Design

Post by DaveC »

Hi Brian -

A nice looking design. Seems to have most everything you'll need at the outset.

Yeah, it's probably not the "final" design.. but it final for this stage... and that's a good start.

I'm in general agreement with Doug, that big windows have some value, although as Carl points out, there's also a liability. Implosions can spoil a whole afternoon....

So I tend to like nice tough pryex or even fused silica (but $$$ for that)... for the window, and a slab of leaded glass mounted outside for Xray control. A sacrificial piece on the interior, will keep most of the nasties away from the viewport.

I actually have a 5 way cross - same size as your dwg, and it is very useful for many types of experiments. Add in a autoclave type door, and you've got accessibilty and convenience.

We'll all be eager to see the finished product and experimental results.

Dave Cooper.
bk8509a
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Re: Final Design

Post by bk8509a »

Just read through everyone's comments.

First thing, thanks for all the comments and praise, means a lot to me.

Secondly, some asked, but I have Autodesk Autocad 10 64-Bit. The way I designed (most) of this chamber is by going to Kurt Lesker's website. On the left hand side there is a link that says "VacuCAD Service". Sign up with it and then go to any part and you can pick up the 2-D drawings. Some parts, however, did not have a drawing. The electric feed through and view port were designed by me in CAD. That's why they're a lot simpler that the other parts. From there you just copy and paste all the parts on one board and line them all up.

There were three main design critiques: View port, D2 input, and vacuum transducer placement.

Sadly, I cannot fix the transducer positioning due to money. Where it is now is where its going to have to stay. I will be using a Convectron brand of transducer and I'll hope for the best.

When it comes to D2 gas, as we all know, neutrons come out as well as radioactive tritium. No one at my college has experience with radioactive products such as these, so they've strictly forbidden me to do fusion. We can't get the safety approval from the school because I go to a small liberal arts school. I might bring the device somewhere to do fusion that has qualified staff, but with the time I'm looking at (2 months from now) and the money I'm look at right now (63 bucks ahead of budget), its best to leave the D2 gas for some other lucky undergrad.

On the view port a few of you mentioned blowing up due to e beams wear and tear and clouding due to sputtering. Great mentions, I'll probably take a Coulter way of doing it and putting in a removable piece of glass in the chamber that I can just toss as I don't think i'll have access to acid.

Parts will probably ordered next week. We already have the HV feed through on its way because it has a 2 week lead time. I feel semi guilty that I'm not scrounging around like all of you did for parts, and I'm really not building anything of my own, but I'm on a serious time constraint. Its my last semester of undergraduate.

By the way, I just got accepted into University of Wisconsin Madison's Nuclear Engineering-Engineering Physics program (for Fusion its number 2 in the nation tied with MIT) so I'll be doing plasma in the future.

I've attached a new plan with dates, name, and an updated grid.

-BK

PS: Nice beard Doug.
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