Re: [usa-tesla] Comments on Tesla's Vacuum Process
- Interesting Fred.... so with the type of diffusion pump of which you
speak, which is a more classical design... this would go behind a
regular vacuum pump, to pull very high vacuums on the final stage?
At 12:57 PM 06/03/2002 -0700, you wrote:
>Jim wrote,"Each day is a new life. Seize it. Live it."
>> But: the exhaust is into the chamber of a lower grade "vacuum pump." Well,
>> just replace this vacuum pump with another diffusion pump, perhaps using a
>> different fluid. Add stages as needed. The final stage can well be
>> exhausted to
>> the outside air, and the fluid could be air also (instead of a boiler in
>> this stage, an air compressor could be used.
> Needless to say I have BUILT these pumps from parts. I have
> cleaned these pumps using powerful solvents and sand-blasting.
> One cannot get any diffusion pump I have ever seen to work
> near atmospheric pressure. The stream of hot gasses must be
> undisturbed and must be at supersonic velocities. This requires
> very low pressures. At atmospheric pressures this gas stream
> would be far far too messy. This 'venturi' thing you referred to
> is not necessary in a diffusion pump as we are at very very low
> pressures already. The air molecules which get into the diffusion
> pump are swept downstream by the re-directed flow of oil or
> mercury molecules. How? Well, there is a heater/boiler in the
> bottom of the diffusion pump that acts much as the heater in a
> coffee percolator, only this happens at a very low pressure instead
> of atmospheric pressure. The boiling liquid yields high-velocity
> gas molecules (oil or mercury) which go up a tube in the central
> core of the pump and exit at various heights through slots in the
> side of this tube. Above and around these exit holes are umbrella-like
> baffles which goes all around the central tube. This ultrasonic
> stream of oil or mercury molecules hits this umbrella and changes
> direction to downward. A very clean direction change. Any air
> molecules which happen to drift into the pump body from above will
> get caught up in the downward stream. The idea is that the oil or
> mercury molecules will transfer some of their kinetic energy to
> these incoming air molecules and direct them towards the output of
> the diffusion pump so that the backing pump can suck them away.
> There the molecules of oil or mercury hit the cold walls of the
> diffusion pump where they immediately condense to a liquid, and the
> molecules of air keep going towards the pump output. In this process
> of condensing, any oil or mercury molecules which evaporate or bounce
> off the diffusion pump's cold inner walls also eventually get hit by
> the fast stream and are also pushed back down towards the pump output.
> Thus they eventually all condense into a liquid, and run back down
> into the boiler section and so they do not get pumped away by the
> backing pump. They get heated up again and go back into the ultrasonic
> vapour stream headed up the central tube.
> There are a FEW molecules of diffusion-pump liquid which may migrate
> upwards and out of the diffusion pump during operation. This is normal.
> To prevent these from getting into the vacuum system being pumped,
> there is usually a cold trap of some sort at the top of the pump
> which is water cooled or (more usually) liquid-nitrogen cooled. When
> the back-streaming molecules of diffusion-pump liquid hit the
> surface of the cold trap, they freeze solid and stick there. This
> cold trap also usually does a good job of condensing other incoming
> molecules, like carbon dioxide, water and argon.
> Needless to say, this kind of diffusion pump depends on gravity to
> keep the liquid where it belongs, at the bottom of the pump. Thus
> a diffusion pump must operate in the upright or near-upright position.
> .. Fred Bach music@... Opinions are only mine.
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--David Guy Powers--
- Who are terrorists? Your guess is as good as mine, and who sponsors terrorism? I thought
that this connection was rather interesting. It is probably just the public tip of the ice burg?