Who has the largest chamber? Any pics?

[RobertMendelsohn]

Not to start some sort of measuring contest, but I'm interested in very large chambers, and I'm curious if people have some, and if so how they set them up. While large chambers can be wasteful for fusors, they obviously have other advantages. If you have a large chamber, I would be most appreciative to hear from you. What pumping modalities did you use, why did you get a large chamber, and what has your experience been thus far?

At the end of the day, NASA will always win with their truly massive vacuum chamber, 130 feet in diameter and 150 feet tall. Coincidentally, a friend's family member is an engineer at NASA responsible for a different extremely large chamber (55ft diameter by 90ft tall), and I was able to tour it... I have never seen such large pumps and vacuum systems in my life. Amazing engineering!

[Richard Hull]

The largest chamber ever used for a fusor by someone is shown in these three images. Can't remember the name, they came, they never claimed fusion, no longer here, to the best of my knowledge. Overkill on steroids. Bigger is not necessarily better where there is no will to continue. Super vacuum system obviously used and constructed for other purposes than doing fusion. Intrinsically a non fusor, but was posted here way back when.....

If the fellow who posted this is still here, I apologize for the humor. Give us more images and a report on what happened here.

Can anyone here give me the history on this or remember who it was? Someone of us old boys has got to have a memory better than mine.

Richard Hull

[Rich Feldman]

The metal bell-jar chamber in pictures reposted by Richard appears to have coolant pipes on the outside.
Reminds me of one in somebody's garage one county away from me.
Used for evaporating reflective and corrosion-resistant coatings onto amateur telescope mirrors.

The big NASA chamber (at which facility?) reminds me of an anecdote from Voyager spacecraft development at JPL in the 1970's, where I worked a couple of summers.

Space probe mechanical designs are constrained not only by size of payload shroud on the launch vehicle, but by size of the available thermal vacuum test chamber and its door.

Most pictures of Voyager omit the solid fuel propulsion module. Designed and integrated as part of s/c rather than launch vehicle, it was jettisoned after boosting the probe into Jupiter transfer orbit.
To compensate for unpredictable off-axis thrust, it has thrust vector control engines (+/- pitch, +/- yaw) each able to deliver a required minimum turning moment (torque).

Now torque is product of thrust, engine distance from center of mass, and sine of the angle between thrust axis and line to center of mass.
In this case it was tricky to trade off the thrust (constrained by catalog of qualified monopropellant engines),
length of the outriggers (constrained by the thermal vacuum chamber for testing the relevant assembled sections),
and thrust angle (constrained by tolerable impingement of exhaust plume in vacuum upon the main engine nozzle).

[Justin Fozzard]

I have a fairly large 2ft diameter by 4ft chamber with a 12" diffusion pump backed up by an oil-free 100cu.m/hr rotary pump.
The chamber was originally used for metallising fingerprints in a forensic laboratory. It has a removeable sliding inner sample holder along with high current feed rails for tungsten filaments used to evaporate aluminium during deposition.

I plan to use it for magnetised plasma experiments where I can run the magnet coils inside the chamber with the 200A feed rails powering them. I have a 12" cryopump and helium compressor system that can be fitted to the chamber for oil-free vacuum experiments if needed.

I've mounted it on a very heavy duty trolley that is able to support the 750kg weight of the chamber and diffusion pump. The whole system can now be easily wheeled around the lab and stored away when not in use.
I've also had to get a new 240V 100A electrical feed to my lab and a 20KW single to 3-phase rotary converter as the diffusion pump has a 4kW heater, the rotary pump uses 5kW motor and the magnet supply draws 10kW.
Here are some photos taken on the day it was delivered:

The 12" diffusion pump and isolation valve:

I've also recently bought a vintage Edwards 19" vacuum deposition system for smaller experiments:

[RobertMendelsohn]

Justin, that is absolutely amazing chamber and pump. That is one of the largest diffusion pumps I have seen! Thank you for sharing.

[Scott Moroch]

The fusor built by myself, Tim Koeth, Jay Howson and Jim Krutzler uses a ~28" diameter spherical chamber.

We use a small turbo pump (50 l/s I think, I will have to check). It reaches low E-7.

-Scott

[Richard Hull]

This U of MD team is a regular at HEAS October flea market and conference. Scott has been on the Fusor.net for some time as many here know. Tim Koeth is more or less the guiding light of the group and is a professor at U of MD.
I look forward to their appearance in October with Scott, Jimbo and Tim. Plus, they are a big seller of surplus stuff that is to die for! Scott!... That is a beautiful fusor setup and I hope to see your contingent down here in 1 month from now.

Richard Hull