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Long segmented spark gap.

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radiotech

Tue Jul 13 2010, 10:06PM

Registered Member #2463 Joined: Wed Nov 11 2009, 03:49AM
Location:
Posts: 1546

What would be the use for a spark gap (if it is a spark gap) consisting of about 30 silver metal washers (look like 5/16 inch
folded into saddles and glued to two rods inside a 1/2 inch thick plexiglass case about 24 x 6 x 6 inches. Two high voltage wires are connected to the edge of the first and last washer in the string. The gaps between the washers is about 1/4 inch.

Two holes , either end about 3 inch dia. many small countersunk machined holes in the sides of the box. Box is fastened together with clamp-like fittings machined into the case as if they did not want it to come apart.

If I get closer to it, will post photo.

Patrick

Tue Jul 13 2010, 10:44PM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

Well I fail to understand the problem, its a spark gap, use it like that. Change the gap for your voltage.
Spark gaps can fail explosively, so that explains the straps.
Also post a pic.

radiotech

Thu Jul 15 2010, 12:31AM

Registered Member #2463 Joined: Wed Nov 11 2009, 03:49AM
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Posts: 1546

Getting closer to bringing the thing to a place to photograph it.
there are actually 4 cables, not two. The rods holding the washers
is actually a tube through which are threaded a high voltage wire
terminated outside but left open at the other end of the tube. Also three capacitors are there two of which are Dublier 33.5ufd WV 10 kVDC Test 15kVDC made by Dubcon works England. Likewise housed in plexiglass boxes.

Patrick

Thu Jul 15 2010, 12:50AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

oh... well that may be different then a traditional gap, post a pic so we can see.

radiotech

Mon Jul 26 2010, 05:15AM

Registered Member #2463 Joined: Wed Nov 11 2009, 03:49AM
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Posts: 1546

The box has finally arived at the desk. Two circuits consisting 0f 18 washers glued onto a platic tube with 1 wire connected to the first and the second wire passed through the plastic to the last washer the wires are soldered to the first and last washers.

Images end view of box, looking into broad side , then narrow side, then a curious melt pattern on box outer surface which appears in several place, resembling a slightly distorted sin wave.

It may be some device with the spark gap incidental to. Its made of 0.75 inch plexiglass

Anyone seen anything like this before? Some clues as to origin point to the Chemistry Department of UBC circa 1950-1960.

1280121333 2463 FT92655 Surfacemeltpatternsparkbox

1280121333 2463 FT92655 Sideviewtopsparkbox

Mon Jul 26 2010, 05:42AM

Registered Member #2372 Joined:
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Posts: 62

could be for a laser. I have seen something vaguely similar that was used as a preionizer for a TEA CO2 laser which had some flat electrodes near a bunch of little preionizer things about 18inches long.

radiotech

Mon Jul 26 2010, 07:14AM

Registered Member #2463 Joined: Wed Nov 11 2009, 03:49AM
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Posts: 1546

The laser sounds reasonable. The case is built to withstand some pressure and there are 5 sets of holes facing each other to hold (mirrors?).

Also as mentioned the suraces is marred by those wavelike melt patterns. Here is another attempt to image one of them.

Antonio

Mon Jul 26 2010, 05:24PM

Registered Member #834 Joined: Tue Jun 12 2007, 10:57PM
Location: Brazil
Posts: 644

What would be the current through this device when it sparks? With any reasonable average power the support plastic rod would melt, burn, or both. The sparks would track over the plastic surface, and sparks are -hot-.

HV Enthusiast

Mon Jul 26 2010, 06:17PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
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Posts: 3068

Maybe its used for some sort of electrolysis or hydrogren generation or something like that. Does it look like you would submerge that thing or pass liquid through it?

radiotech

Tue Jul 27 2010, 06:22PM

Registered Member #2463 Joined: Wed Nov 11 2009, 03:49AM
Location:
Posts: 1546

I dont think it is a liquid device. The two gap rods could have an electrical model of two washer (plates) seperated by the dielectric of the wire covering, air space,plastic tube, glue (holding the two washers on). there is a lesser capaciity of the air gap between all the othe washer's edges and If the gap was in (brush discharge) the ir woild be capacity to all the other washers through the tubing and wire covering, to the wire connecting the far washer. No care was taken to smooth the washer edges.

What kind of a beam could write a melt pattern on the box outer surface in several places that appears as a big sin-like pulse, deep gough, diminishing like a damped wave (lesser gough) running abour 8 inches in length along a curved path. I am making a tracing of these arcs with tracing paper and charcoal. Its not an electric arc because the plastic would have carbonized. ( Superheated steam jet
comes to mind(from time spent around power boilers).

I haven't seen such a mark on the surface of plexiglass,

This box lookes like it has seen rough service in that they have repaired a few parts close to the edge.

The papers on TEA CO2 lasers that I tried to get have got begging bowls demanding payments. Annoying since most of those university papers were funded via public purse and were free in the first days of the net.

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