Homemade Vacuum Tube

[AlekZ]

Hello everybody,

it's experimental red magic eye:
http://tubedevices.com/alek/pwl/oko/oko_e.htm

and film during working:

http://tubedevices.com/alek/pwl/oko/oko.mov

[AlekZ]

Amplifier with globe tubes:
http://tubedevices.com/alek/pwl/wzma...macniacz_e.htm

[ethermion]

You know, somebody should make this guy stop. It really is not fair. While I am doing honey-do (chores assigned by my wife), this guy is making red magic eye tubes. Completely not fair.

Joking, of course. I am very impressed!

-e

[KISS]

I've sealed reactants like phosphorous and zinc under a vacuum and have built ampoules of the same for crystal growing at work. The vessels were quartz and diffusion pumped. The hi vacuum gauge was a cold cathode pirani type.

The torch was hydrogen/oxygen for purity.

[AlekZ]

->Kiss
Are you sure that was cold pirani? Not cold Penning gauge?

I promise you that it's finishing link:

http://www.tubedevices.com/alek/pwl/..._produkcja.htm

It's making of the triode, step to step in my kitchen laboratory.

The next links in new year

Best regards

Alek

[KISS]

Pirani. Uses a magnet and, I belive a 3K or so accellerating potential with a rectangular grid.

Every time I have to seal something, I always have to practice once if I haven't done it for a while.

We used to take a quartz 1" square tube and attach a round piece of quartz about 1/2" in diameter to make it easier to seal for evacuation purposes.

In one of the processes whe had to introduce a controlled leak in an inner chamber, The leak was created with a hand-held telsa coil device. 25 years ago, I did it regularly.

I could do it now with a little practice. It's like riding a bike.

I've used oxy/acetelene, propane, Mapp gass and oxy/Mapp gas torches, but not for glass blowing.

Just,like regular or silver soldering. When Learn the skill, It stays with you forever.

I once taught a novice new home owner to sweat copper pipe. I did the more difficult joints. There was a fair amount of watch. I had him solder the joints upside down. Pipe below fitting, so you see the solder wick like it should by capillary action.

Later he did about 40 joints for another project and had no leaks.

I've tried TIG, MIG and stick welding without much practice. The joints looked good.

I'm really glad that someone turned me on to one soldering trick for old pipe that has a little water that wouldn't drain. Put bread in the pipe to soak and stop the water. Works great.

BTW. If it's not obvious, the best way to seal a glass end is to put your manifold overhead. You can have a number of take-offs and use glass shut off ***** that are lubercated with vacuum grease. Later we went to a better valve at about $400 each.

We used Cajon fittings to make the seal from the take off to the tube requireing sealing. The Cajon fittings have O rings on both sides. You can make adapters for various size glass.

I loved working with quartz. I didn't like pyrex. Probably because the Oxy/Hydrogen torch was too hot.

[AlekZ]

Hi,
It's rather not Pirani, because in Pirani is hot platinum wire. It uses the thermal conductivity of gases to measure pressure. It's good up 10^-3 Torr to 760 Torr. For highest vacuum (even to 10^-8 Torr)is used Penning gauge. There is magnet, cold cathode and high voltage:?
I found here about Pirani and Penning in english language:
http://en.wikipedia.org/wiki/Pressure_measurement

You are happy. You can use pyrex and quartz
I can use soda (or lead) glass only. I have too cold torch (terraneus gas-air).

Unfortunatelly I don't understand it:

"If it's not obvious, the best way to seal a glass end is to put your manifold overhead. You can have a number of take-offs and use glass shut off ***** that are lubercated with vacuum grease."

Best regards
Alek

[KISS]

Your right on the vacuum guage part. It was definately a cold cathode guage and about 3 KV with a magnet so it wasn't a Pirani guage.

These were the fittings used to make the connection from the manifold to the glass stub:

http://www.swagelok.com/downloads/we...N/MS-01-32.pdf

Diagram of the sealing set up:

Ignore the ".". I'm assuming that this board doesn't like ASCII art. (i.e. leading spaces)


.....VG <- Cold cathode vacuum gauge
.......*
.......*
********** <- Vacuum manifold w/(2-3 drops)
..................*
.................(x) <- Valve
................. *
..................UT <-Ultra-torr fitting
..................*
..................*
...................* <--- torch area
..................*
..................* <- part to be sealed


The manifold was all glass. Didn't have to be, but was. (x) was iinitially a valve made entirely of glass. The manifold used ground glass joints with a wax seal. All of this was located so the the "torch area" was at eye level when standing. A fire proof countertop was below.

You had the standard foreline/rough/hi-vac valves and thermocouple gauge elsewhere. Diffusion pump required liquid nitrogen.

All the parts to be sealed were attached and the valves (x) were opened and the parts were evacuated. You would then close the valves (x) of the the one's you were not sealing at the time and then use a hand-held torch to seal at the torch area.

Gravity let you know when the glass was fluid enough. The use of a hand held torch allowed you to rapidly move the torch to all sides of the joint. If something went wrong, the corresponding valve (x) could be shut.

Since evacuating took a long time compared to sealing, it made sense to have multiple ports.

I hope this makes more sense.

[KISS]

Here is a link for some ground glass joints and vacuum stop *****:

Instead of using grease for the tapered joints wax was used.

http://www.ecu.edu/glassblowing/glasscomponents.html

http://www.ilpi.com/inorganic/glassware/stopcocks.html

Some greases and waxes are located here:

http://www.2spi.com/catalog/vac/apiezon.html

[KISS]

I found this article on constructing vacuum systems for neon signs:

http://www.tecnolux.com/index.php?op...d=72&Itemid=92

Look at the base url too:

www.tecnolux.com