My fusion setup
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- Real name: Steven Whittam
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My fusion setup
Finally there and ready to do experiment
Looks like no leaks
Down to 150 micron on pump side
Just waiting till below low enough to turn on diff pump
Looks like no leaks
Down to 150 micron on pump side
Just waiting till below low enough to turn on diff pump
- Richard Hull
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Re: My fusion setup
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
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
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
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- Real name: Steven Whittam
- Location: Melbourne/Australia
Re: My fusion setup
Well looking into a new chamber
If parents lend me cash gona have one built
What you think Richard?
If parents lend me cash gona have one built
What you think Richard?
- Richard Hull
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Re: My fusion setup
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
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
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
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- Posts: 103
- Joined: Fri Jan 24, 2014 8:45 am
- Real name: Steven Whittam
- Location: Melbourne/Australia
Re: My fusion setup
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 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
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 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
- Dennis P Brown
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Re: My fusion setup
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.
- Rich Feldman
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- Location: Santa Clara County, CA, USA
Re: My fusion setup
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.
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
- vince_Darmancier
- Posts: 42
- Joined: Mon Dec 10, 2018 11:04 am
- Real name: Vince Darmancier
Re: My fusion setup
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
https://www.ebay.com/itm/123805495234?s ... 1438.l2649
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- Real name: Christoffer Braestrup
Re: My fusion setup
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.
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.
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- Real name: Steven Whittam
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Re: My fusion setup
Got everything need For between diffusion pump and chamber
Got couple of parts in mail for sorting leaks between diffusion pump and vacuum pump
Got couple of parts in mail for sorting leaks between diffusion pump and vacuum pump
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- Joined: Fri Jan 24, 2014 8:45 am
- Real name: Steven Whittam
- Location: Melbourne/Australia
Re: My fusion setup
Hey
Managed to get to about 360 micron
Here’s some pics
Managed to get to about 360 micron
Here’s some pics
- Richard Hull
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Re: My fusion setup
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
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
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
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- Posts: 103
- Joined: Fri Jan 24, 2014 8:45 am
- Real name: Steven Whittam
- Location: Melbourne/Australia
Re: My fusion setup
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
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
- Dennis P Brown
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- Real name: Dennis Brown
Re: My fusion setup
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.
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Re: My fusion setup
I’ll try get some pictures tomorrow
- Richard Hull
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Re: My fusion setup
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
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
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
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Re: My fusion setup
That is one massive chamber! Going to need a lot of deuterium to operate, no?
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- Real name: Steven Whittam
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Re: My fusion setup
Diff pump Iso160 to kf50 adapter to dn40 chamber
- Dennis P Brown
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Re: My fusion setup
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.
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.
- Richard Hull
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Re: My fusion setup
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
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
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
-
- Posts: 103
- Joined: Fri Jan 24, 2014 8:45 am
- Real name: Steven Whittam
- Location: Melbourne/Australia
Re: My fusion setup
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 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
- Dennis P Brown
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- Real name: Dennis Brown
Re: My fusion setup
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.
- Rich Feldman
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- Location: Santa Clara County, CA, USA
Re: My fusion setup
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.
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