Coil inside of plasma tube

I assume the leads will be molded/passing through the glass envelope?

How do you plan on getting the Kynar wire molded in this with out it melting? Kynar at extrusion is ~ 550F to make it soft enough to apply FEP (teflon) is around 750F.

How much heat is going to be on this wire inside?

Kynar is not very adhesive so using a ported hole with sealer may be short lived before the gas leaks. I suppose chemicals have come a long ways these days, it may not be the case any more.

This is all about construction not operation concerns. Jamie

Hmm.. can you test the wire insulation under simulated conditions in a bell jar?

Best regards, Spehro Pefhany

Must the coil be within the plasma tube?

It appears that you actually don't want the coil to be in contact with the plasma. Only to create a magnetic field inside of the assembly. If so, can you locate the coil just outside the plasma tube and adjust the coil current so as to generate the requisite B field inside the slightly larger area?

For this exp the plasma needs to be physically both inside and outside of the coil. IOW the coil is air wound before insertion.

James

Good point. Glass melts beginning at 2500 F. Is there any wire insulation that will withstand this?

The coil will be placed in the center section of a tube and the ends sealed. It can be as far away from the torch as required. The problem is getting the wire OUT.

Does anyone have anything further on this ported hole approach?

James

Running the wire through the glass is the parlour trick. You can do it with tungsten wire, by heating the wire with a torch till it turns green, and then fusing it in the glass, or with Kovar wire.

Good luck running copper wire through glass without leaks.

Cheers

Phil Hobbs

What if you essentially coat the wire with glass instead?

Something like a klein bottle? This would get you the separation of having the coil outside but allow plasma to be inside and out. It should not be difficult to make. You are effectively just coating the wire with glass.

It may be hard to visualize but think of having a glass coil(like some of the light bulbs you see) that is inside the vessel.

The added benefit is that you do not have to worry about leakage at the ends. You can also run multiple conductors through the coil if needed.

Close (and there are lower temperature glasses). Mineral insulated (MI). It's used in some process control applications because it will still function in extreme conditions such as a refinery fire. The outer shell could be something like Inconel.

Best regards, Spehro Pefhany

You mean like this?

Best regards, Spehro Pefhany

Most tubes use steel(nickel plated) wire annealed to the glass to make the outside world connections. And I'm sure most tube guys will agree.

And yes the Kynar would melt.

Why don't you check with the Tube manufacturers? Like Xray tubes and such. It's a craft, and they would know best how to organize the inside such that it would work.

You might even be able to put a tube within a tube to isolate the winding.

Cheers

Yeah!

You do not need something as fancy,

cross section,

|----------------| | | | ___ ___ | | |+| |+| | | |+| |+| | | |+| |+| | | |+| |+| | | |+| |+| |

---- ---- ----

would work just as well. Basically like an E-Core transformer but it is cylindrical. (the + being the coil)

This would be even easier to make and probably do a better job.

On a sunny day (Wed, 30 Nov 2011 03:46:19 GMT) it happened snipped-for-privacy@questop.com (James Baker) wrote in :

Why not put the coil in a glass tube for insulation?

You know what ,that's a good idea however, I think the thermo movements may crack the glass around it.

A double lined tube with only the center tube having the gas and seal is what's needed from what I can see. standard practices how tubes are assembled can be used here. Otherwise, since he wants it insulated, why would it need to be directly inside? Unless he is looking for a faster change ?

The whole unit can be made to plug into an octal base socket for example.

There is a process I've seen that I really don't understand why it was done that way. They made a coil inside a tube from miniature Fep coax. attached the centers to the feed through pins in the base of the glass. Filled the base of the glass with a sealer that covered the pins up to the center conductors insulation and over a bit, there by keeping it sealed from what ever they were putting in the rest of it. The shield was then pushed back down to the bottom after the first set harden and then a thin coat of the same sealer was applied to attach the braid to base with out it shorting to the center. I assume they may have done this to keep the shield from sliding around.. I didn't see what was in the rest of the tube.

Jamie

That sounds hard. Can you use epoxy rather than glass to make a seal? And you've still have a potential leak path between the wire and insulation. Is the cell sealed or can you pump it out? What level of vacuum?

George H.

What's the size of the tube and coil?

I suppose the question is: Must the plasma inside the coil be able to pass to the outside and vice versa? How much can the coil block the passage of plasma between these two regions?

What you have there is blocked at one end. Plasma that wants to get from the inside to the outside has to go around the end of the coil enclosure.

Spehro's condenser example leaves multiple paths between both regions along the length of the apparatus, with something live 50% blockage.

The wire is actually an nickel-cobalt-iron alloy , with a controlled coefficient of expansion to match that of the glass.

That is what made all-glass tubes with lead-in wires thick enough to be used as standalone pins possible.

That sounds awfully close to what is currently called an "Induction = Lamp". You might compare your construction to theirs.

?-)