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A question about treatment area vs Volume

Two styles of electrostatic treatment vessels, one is a circuitous snake route. Each trough has 11" square plates 1" apart. Easy to calculate plate area vs volume. Now, also looking at a coaxial pipe within a pipe. 4" inner pipe with an 8" outer pipe. I can't get my head around the treatment area vs volume on coaxial pipes. The electrostatic voltage will have to higher because of more distance between plates, not a problem. Is the plate area just the area of the inner pipe? Is it a geometric mean of the inner and outer? Trying to maximize treatment area vs volume. I like the coaxial version, my son is more involved with the circuitous snake route version. Sadly he is so busy with other work that his build is going slow.

Add to that he is back in school to add a mechanical engineering degree to his chemistry degree. Hurry up kid! I want to see it. :-) Thanks, Mikek

Reply to
Lamont Cranston
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Pretty much.

The field is more intense around the smaller inner pipe, so that's where most of the action will happen.

Coax set-ups are less fiddly, and have fewer spacers to with fewer options for the spacers to move around, but it's hard to get a lot of surface area,

Reply to
Anthony William Sloman

So maybe a 6" or 7" inner pipe and a 8" outer pipe to get more area and just make it taller to get the required volume. Will calculate to see if what pipe sizes would be a reasonable height. Thanks, Mikek

Reply to
Lamont Cranston

This are thought-provoking questions. I think I would look up the design equations for an air-filled coaxial transmission line and go from there. In fact, I believe I have seen equations for the capacitance of a coaxial capacitor.

Anyway, good luck.

John

Reply to
John Smiht

Here ya go...

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Reply to
John Smiht

Even though I'm looking at the equation, I still can't reconcile B/A and how it relates to the area of the inner electrode (pipe). Weak math background. But, I did note, that making the inner pipe larger and the length longer increases the capacitance, there is a limit where our square wave drive starts to have a long rise and fall time. (6MΩ series resistor to work the switch against.) We may just fall back on 60Hz drive instead of the variable frequency drive that we have now. Here's the calculator I used.

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Thanks, Mikek

Reply to
Lamont Cranston

Ok, Mike -

The surface area of a cylinder is the perimeter times the length. So, in this case, they say the radius of the inner cylinder is a. The perimeter of the circle is the diameter of the circle times pi. So then the perimeter is 2*a*pi. Well, then the area of the inner tube is

2*pi* a*L where L is the length. Make sense?
Reply to
John Smiht

Oh, I understood how to calculate the area of the inner pipe and I thought that might be the number to use for area/volume question. I just thought in the equation on the page you posted that the b/a should be b-a to get a distance between plates. But I'm not to concerned, I can put some numbers to it and see it work. Thanks, Mikek

Reply to
Lamont Cranston

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