Have you ever thought about what insulators are good at constructing HV devices, like ESLs? I mean some materials do not attract dust at all (e.g. wood, ceramics, vax), while others do (e.g. glass, paper, most plastics).
Finding the right materials for cable insulation, structural construction, dust cover would eliminate the need of disassembling the ESL from time to time and dust them internally. I do this for my Quad ESLs every two year or so. Same for the TV set. I vaguely remember something from chemistry lectures at school that there are polarized and apolarized materials, but no more.
Finding the right materials for cable insulation, structural construction, dust cover would eliminate the need of disassembling the ESL from time to time and dust them internally. I do this for my Quad ESLs every two year or so. Same for the TV set. I vaguely remember something from chemistry lectures at school that there are polarized and apolarized materials, but no more.
Interesting question. If something can hold a charge stably on its surface, it won't be a dust collector. Unfilled plastics are an example of things that DO hold a stable charge. Ditto for glass. Wood doesn't, but that's because wood has a small amount of electrical conductivity (charges spread and migrate); it's fine for frames, but a lousy insulator material. Same for paper.
Some very good insulator plastics collect dust, orhers don't. Same for glass: my TV screen gets dusty very rapidly, but I've never seen a dusty ceramic isolator. There should be something in the material structure - any chemists out there?
Actually, I am a chemist.
Whether or not you see dust on ceramics depends on the particular ceramic material. Some can stabilize charges easily (high K materials, for instance), some can't. Nearly any non-hygroscopic plastic will attract dust unless there are antistat additives- polymer polarizability allows charge stabilization but poor mobility. In my plastics business, we have to firmly ground everything that the plastics rub against during transport (pipes, hoppers, bins, silos), otherwise the triboelectric effects, charge stabilization, and poor mobility all come together in a perfect storm- we've had some pretty impressive lightning bolts from ungrounded hoppers...
Whether or not you see dust on ceramics depends on the particular ceramic material. Some can stabilize charges easily (high K materials, for instance), some can't. Nearly any non-hygroscopic plastic will attract dust unless there are antistat additives- polymer polarizability allows charge stabilization but poor mobility. In my plastics business, we have to firmly ground everything that the plastics rub against during transport (pipes, hoppers, bins, silos), otherwise the triboelectric effects, charge stabilization, and poor mobility all come together in a perfect storm- we've had some pretty impressive lightning bolts from ungrounded hoppers...
Acoustat's solution...
Jim Strickland's solution has been mentioned before and is worth repeating.
Simple solution to the dust collecting issue. Most of the time the air has a positive charge. This does vary with weather conditions but is true most of the time. So Jim simply chose to use a positive supply voltage to charge the diphragms. Acoustat's have no dust cover and after owning a number of sets I would have to agree that they just don't need one.
After 15-20 years the diaphragm will build up contaminants which will slowly bleed off a little charge. This is not a major issue but if you wish you could wash the panels with a combination of detergent and degreasing agent. Allow the rinsed clean panels to fully dry and you are set to go again.
Jim Strickland's solution has been mentioned before and is worth repeating.
Simple solution to the dust collecting issue. Most of the time the air has a positive charge. This does vary with weather conditions but is true most of the time. So Jim simply chose to use a positive supply voltage to charge the diphragms. Acoustat's have no dust cover and after owning a number of sets I would have to agree that they just don't need one.
After 15-20 years the diaphragm will build up contaminants which will slowly bleed off a little charge. This is not a major issue but if you wish you could wash the panels with a combination of detergent and degreasing agent. Allow the rinsed clean panels to fully dry and you are set to go again.
Perhaps a once over with one of these brushes will help....
http://www.angelfire.com/electronic/cwillis/rad/brush.html
The company that produces these is literally only a few miles away from me.
http://www.nrdstaticcontrol.com/
http://www.angelfire.com/electronic/cwillis/rad/brush.html
The company that produces these is literally only a few miles away from me.
http://www.nrdstaticcontrol.com/
The material is inconsequential, all that is important is a charge difference. if you have a difference of 3,000 volts inside your esl, however slightly positive the air is etc, is moot. and yes it is possible to have a charge difference between associated with teflon, and wood, and glass, and human hair, and dog doo...
Basically an esl is a little particle accelerator : )
Basically an esl is a little particle accelerator : )
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