ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Electrical Engineer - Photovoltaic Systems
Powdered electrons, eh? Just add water?Excellent!
But the furnace, that which we called the 'EB', didn't have a tungsten filament. It had a thing like this:
View attachment 7025
Our first design we considered a success (this was 1980). We were easily melting titanium with it. So, what did the titanium do with those electrons??
One day a bunch of military types came in and told us we had to up the power to many times what we had designed. So, months were spent tearing this huge vacuum furnace apart and installing bigger 'guns'. When we were done, the furnace would easily boil titanium. The military types came back, saw the boiling titanium and said it was good. Much hand shaking and back slapping ensued with a five star tour of the rest of the plant to follow. That was on a Friday. When I got back on Monday, the entire unit was gone.
Well, all gone except for the hopper that the engineers told us was used to feed the EB with powdered electrons. That was still there and looked strangely like some sort of sand blasting equipment.
Seriously, the electrons for all these devices come from a power supply that basically pumps them around in a circle. You don't need a "supply" of electrons; they are lying around everywhere.
Electron guns are just glorified incandescent light bulbs. They run a current through a piece of metal (the cathode) heated to the point where the electrons are loosely bound to the metal and put a highly positively charged grid nearby. The attractive force of the grid extracts electrons from the cathode. Many get captured by the grid, but the ones that are on a path through the center of a hole in the grid get through and they are traveling very fast. Their kinetic energy is converted to heat when they strike the titanium in your furnace, which melts and eventually boils it.
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