My fusion setup

Current images of fusor efforts, components, etc. Try to continuously update from your name, a current photo using edit function. Title post with your name once only. Change image and text as needed. See first posting for details.
steventw
Posts: 103
Joined: Fri Jan 24, 2014 8:45 am
Real name: Steven Whittam
Location: Melbourne/Australia

My fusion setup

Post by steventw »

Finally there and ready to do experiment
4E06C402-71F9-46D1-9703-4596BAB9A44E.jpeg
Looks like no leaks
Down to 150 micron on pump side
Just waiting till below low enough to turn on diff pump
User avatar
Richard Hull
Moderator
Posts: 14991
Joined: Fri Jun 15, 2001 9:44 am
Real name: Richard Hull

Re: My fusion setup

Post by Richard Hull »

You are off to an interesting start. I fusion is your goal, the chamber is rather large and will require a significant amount of very expensive deuterium. I assume that top is plastic. If it is, you will never really pump that down to fusion pressures and the heat from electron/ion beams hitting the plastic will cause it to outgas horribly.

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
steventw
Posts: 103
Joined: Fri Jan 24, 2014 8:45 am
Real name: Steven Whittam
Location: Melbourne/Australia

Re: My fusion setup

Post by steventw »

Well looking into a new chamber
If parents lend me cash gona have one built
Design
Design
What you think Richard?
User avatar
Richard Hull
Moderator
Posts: 14991
Joined: Fri Jun 15, 2001 9:44 am
Real name: Richard Hull

Re: My fusion setup

Post by Richard Hull »

I think way too big! 35cm!! 20 cm is way too large. Why re-invent the wheel with a rectangular chamber. The fusor fuel is deuterium and it is very expensive. we do fusion by leaking in deuterium against a pump thus the deuterium is fed to the chamber and then pump on thru out the vacuum pump system into the outside world. We are throwing it away while doing fusion. The reason for this "differential pumping" is too complex to explain in a paragraph but it is what is demanded for continuous fusion operation.

The bigger the chamber the more deuterium is wasted by "pump through". Try and use stock vacuum ready gear as it is made to seal properly in vacuum work. 15 cm chamber diameter is about right this can be in the form of a cylinder, sphere or vacuum rated cross. Stay clear of sharp angles in the system, like rectangles and square metal areas, they mess with the electrostatic acceleration field. You would idelly like to see this field rather uniform to avoid arcing.

I hope you have read this FAQ

viewtopic.php?f=24&t=13508&p=87970#p87970

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
steventw
Posts: 103
Joined: Fri Jan 24, 2014 8:45 am
Real name: Steven Whittam
Location: Melbourne/Australia

Re: My fusion setup

Post by steventw »

Hi

Sorry haven’t been around for awhile.
Reason chamber so big is because of prototype of idea is about W30cm X D30cm X H10cm

Prices for getting chamber built out of aluminium where a bit to pricey.
going to try do a welding course in few weeks then advance one covers aluminium


Did have trouble with leaks and pipe work between diff pump and chamber I think was to great could only get to 360
Micron on chamber
When shut valve between chamber and diff pump
The vac pump gauge would drop to 15 micron
But 160 on pump when valve to chamber was open

Managed to find a kf50 gate valve cheap on eBay
Cost about $228 Australia for it plus postage
Is due in mail this Monday/Tuesday
Gate valve
Gate valve
Hopefully helps to shorten pipes between diff and chamber by half and straight line over s bend which prob wouldn’t of helped

I’ll try current chamber with new gate valve and look into a better chamber like round aluminium pipe if can find one the right size if can work out how to mod it.
Will let you know how I things go
User avatar
Dennis P Brown
Posts: 3159
Joined: Sun May 20, 2012 10:46 am
Real name: Dennis Brown

Re: My fusion setup

Post by Dennis P Brown »

That doesn't look like a useful gate valve. It appears to be a fully open or closed system. One requires an adjustable gate valve to be useful for control of deuterium exhaust from chamber and chamber pressure.
User avatar
Rich Feldman
Posts: 1470
Joined: Mon Dec 21, 2009 6:59 pm
Real name: Rich Feldman
Location: Santa Clara County, CA, USA

Re: My fusion setup

Post by Rich Feldman »

Good to see vacuum measurements.
Agree with Steven's approach,
if step 1 is to achieve sufficiently low floor pressure _without_ introducing gas on purpose.
Fix the leaks.
The gate valve won't hurt, except to add connections that might leak.
Not sure how it will help, except for identifying leaks as above or below.

When deuterium time comes, suppose the gate valve can't be adapted to stop in slightly-open position.
Then conductance to pump can be reduced by adding a baffle above the gate valve.
Maybe even one that's adjustable, manipulated (say) by a magnet outside the vacuum.

As a note to other noobs, "gate valve" refers to physical configuration, not to the function of gating a pipe open or closed.
A butterfly valve or ball valve, for example, might go from wide open to vacuum tight but that doesn't make it a gate valve.
All models are wrong; some models are useful. -- George Box
User avatar
vince_Darmancier
Posts: 42
Joined: Mon Dec 10, 2018 11:04 am
Real name: Vince Darmancier

Re: My fusion setup

Post by vince_Darmancier »

I recently came across this neat little hemisphere all stainless steel, very affordable and made right here in Michigan! I think its worth looking into . there is a few size to choose from and the connections are all good to go for high vacuum..
https://www.ebay.com/itm/123805495234?s ... 1438.l2649
ChristofferBraestrup
Posts: 131
Joined: Sat Apr 11, 2020 9:47 am
Real name: Christoffer Braestrup

Re: My fusion setup

Post by ChristofferBraestrup »

You may be aware of this, but the flanges that look like KF40/50 flanges are NOT KF flanges- they're 'tri-clamp' flanges.
Commonly found on brewery/food apparatus. Uses a similar clamp but a wierd O-ring. Can be identified by the round groove in the sealing face. They're inch-standard, not metric like the KF series.

Getting these ports adapted to vacuum instrumentation may cost a lot of adapters or fabrication.
steventw
Posts: 103
Joined: Fri Jan 24, 2014 8:45 am
Real name: Steven Whittam
Location: Melbourne/Australia

Re: My fusion setup

Post by steventw »

Got everything need For between diffusion pump and chamber
Got couple of parts in mail for sorting leaks between diffusion pump and vacuum pump
steventw
Posts: 103
Joined: Fri Jan 24, 2014 8:45 am
Real name: Steven Whittam
Location: Melbourne/Australia

Re: My fusion setup

Post by steventw »

Hey
Managed to get to about 360 micron
Here’s some pics
534A0EEA-3393-4267-9DF5-F05A527135D8.jpeg
36262AEF-E0B8-444A-8E08-72605ABBC502.jpeg
7954492D-99D4-4CD8-B6AD-D8D3321BD7E5.jpeg
05E3BB51-4181-425F-A612-ADA17CD50B6A.jpeg
DD8FBB57-2A55-448B-A0B4-501F4DFA5CEE.jpeg
7C37D485-EB6D-433E-BD32-A5155BF5759E.jpeg
User avatar
Richard Hull
Moderator
Posts: 14991
Joined: Fri Jun 15, 2001 9:44 am
Real name: Richard Hull

Re: My fusion setup

Post by Richard Hull »

Things will get real pretty at about 20 microns and below. Much below 5 microns and all glow will go away.
Vacuum system needs a lot of attention, yet. It is either seals on the chamber leaking or the pump is weak now.

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
steventw
Posts: 103
Joined: Fri Jan 24, 2014 8:45 am
Real name: Steven Whittam
Location: Melbourne/Australia

Re: My fusion setup

Post by steventw »

Still a small leak around seal from chamber to pipework
Got to slightly turn it right way to get to 350 micron or sits around 3000

Pump is good only takes few min to get there
User avatar
Dennis P Brown
Posts: 3159
Joined: Sun May 20, 2012 10:46 am
Real name: Dennis Brown

Re: My fusion setup

Post by Dennis P Brown »

As someone that seals feed-thru's, this is difficult work. Pictures of the external device/setup and a few close up's would be helpful if you want ideas on sealing/leak location.
steventw
Posts: 103
Joined: Fri Jan 24, 2014 8:45 am
Real name: Steven Whittam
Location: Melbourne/Australia

Re: My fusion setup

Post by steventw »

I’ll try get some pictures tomorrow
steventw
Posts: 103
Joined: Fri Jan 24, 2014 8:45 am
Real name: Steven Whittam
Location: Melbourne/Australia

Re: My fusion setup

Post by steventw »

E86F0939-BEFD-4F6B-B322-4C631A45708D.jpeg
CD8983B5-6F6F-4B88-9B1E-82B502134026.jpeg
86DADAAE-7834-40A7-85DD-F53FC62FD5C0.jpeg
steventw
Posts: 103
Joined: Fri Jan 24, 2014 8:45 am
Real name: Steven Whittam
Location: Melbourne/Australia

Re: My fusion setup

Post by steventw »

B47341DF-FD3D-4C31-A5E1-66016181739C.jpeg
User avatar
Richard Hull
Moderator
Posts: 14991
Joined: Fri Jun 15, 2001 9:44 am
Real name: Richard Hull

Re: My fusion setup

Post by Richard Hull »

I just noticed that chamber has handles on it!!! Are they riveted or Welded on? Big leak with rivets, maybe. Also, what kind of gasketing are you using on the ISO fitting to the Diff pump intake. I looks like two red rubber gaskets rather than the normal aluminum run gasket demanded for those fittings. (out gassing?).

The rest of the system with proper KF fittings and proper rings seem a good top end vacuum choice.

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
Matt_Gibson
Posts: 505
Joined: Thu Sep 23, 2021 10:36 am
Real name: Matt Gibson

Re: My fusion setup

Post by Matt_Gibson »

That is one massive chamber! Going to need a lot of deuterium to operate, no?
steventw
Posts: 103
Joined: Fri Jan 24, 2014 8:45 am
Real name: Steven Whittam
Location: Melbourne/Australia

Re: My fusion setup

Post by steventw »

Diff pump Iso160 to kf50 adapter to dn40 chamber
User avatar
Dennis P Brown
Posts: 3159
Joined: Sun May 20, 2012 10:46 am
Real name: Dennis Brown

Re: My fusion setup

Post by Dennis P Brown »

The top cover for the chamber looks to be plexiglass; if so, under heavy electron/ion bombardment that will outgas a great deal. The coupling seal for the electrical connections looks rather questionable. A proper glass plate would be expensive but a metal one, with large enough holes for small glass plate(s) and required feed-thru's would be reasonable - cost wise. A metal cover would certainly improve your vacuum.

Also, your metal chamber does not appear very thick looking at the photo. From the picture, I assume you welded a KF adapter to the base? If so, then that should work. If not, the KF fitting on the bottom used to connect the DP isn't going to hold vacuum very well as the bottom flexes.
User avatar
Richard Hull
Moderator
Posts: 14991
Joined: Fri Jun 15, 2001 9:44 am
Real name: Richard Hull

Re: My fusion setup

Post by Richard Hull »

That is correct, never allow plastic in a fusor chamber with an active plasma in it. It will never stop outgassing under bombardment.

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
steventw
Posts: 103
Joined: Fri Jan 24, 2014 8:45 am
Real name: Steven Whittam
Location: Melbourne/Australia

Re: My fusion setup

Post by steventw »

EA163137-D43B-460A-A776-567C1B27C203.jpeg
At about 4000 micron



This is what I have for connector from pipe work to chamber
I did buy a 2 weld stubs all up because chamber is thicker on bottom like twice as thick as weld stub
So when Tryed to weld the stub would desintergrate before chamber bottom was hot enough to weld to
Chamber/pipe connector
Chamber/pipe connector
Noticed have to slightly turn chamber if stops around 3000 micron then drops to 350 when get the sweet spot
Have Tryed some silicon all around etc to seal it up just waiting for it to dry


Haven’t got any spair cash at moment for new lid
But I’ll keep in mind for next thing buy for it
Just getting one with a viewport and freed through would be hard to find
User avatar
Dennis P Brown
Posts: 3159
Joined: Sun May 20, 2012 10:46 am
Real name: Dennis Brown

Re: My fusion setup

Post by Dennis P Brown »

Don't buy a real vacuum grade, stainless Steel cover ($$$) - rather, get an aluminum plate (close to 1/2 inch thick) big enough to cover your chamber (it can be a square plate.) Then use a 3 inch hole saw to make access for a viewing port. Then drill quarter inch or so holes to make electrical feed-thru ports. This can be done at home with a hand drill but a drill press would be far easier/safer. Adding the glass plate using sealant would be enough to get you into the low microns or even tenths of microns with no problem.
User avatar
Rich Feldman
Posts: 1470
Joined: Mon Dec 21, 2009 6:59 pm
Real name: Rich Feldman
Location: Santa Clara County, CA, USA

Re: My fusion setup

Post by Rich Feldman »

Looks like leftover disks of cast aluminum tooling plate are still available from the S&S Machine company in Roseville, California.
Compared to ordinary rolled AL plate stock, the MIC-6 or equivalent material is naturally flatter & has much less internal stress. So it stays flat even when substantial areas and volumes are cut away.

http://www.sandsmachine.com/alumweb.htm

Aluminum is so much stiffer than plexiglass, it's not even funny. You might find that 3/8" is plenty thick as a cover for your pot. Plenty strong for sure. Call if you want help to figure the elastic deflection under vacuum, in thousandths of an inch. How much does your plastic lid suck in, observed with respect to a straight edge?

If your vacuum problem today is from air leakage where plastic lid meets the pot,
you can find out quick by applying a little oil or grease to outside of joint while under vacuum.
All models are wrong; some models are useful. -- George Box
Post Reply

Return to “Images du Jour”