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not_important
International Hazard
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Might find some of the entries here of interest
http://www.valdosta.edu/~tmanning/research/ozone/
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Pulverulescent
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Yes, that's an interesting site; I was surprised to find so many patents covering UV methods---I'd always assumed UV was so inefficient as to hardly
deserve consideration.
The fact that 10,000 patents have been granted for ozone generators, though, speaks for itself.
And the basic technology has hardly changed since Schonbein's day!
There exists a certain possibility that I may have caught a glimpse of a totally new method for ozone synthesis, but if I can't reproduce the "effect"
I'll end up wasting time and money, however, if it can be reproduced, and developed, the industry may eventually be transformed.
I find myself in an a very odd position, and I'm kinda' stumped!
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not_important
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Reproducing it, and doing tests and measurements is indeed te key.
There's two other possibilities that I see; I suggest these because of the instability of ozone at elevated temperatures.
One is the formation of traces of nitrogen oxides, at low concentrations this may smell similar to ozone to some people.
The other is the formation of iridium oxides and/or finely divided metal ('fumes') I've no idea what odor they might present, nor if a significant
amount could form under the conditions you had. But iridium can be oxidised to the dioxide when heated in air, and that breaks down into the metal
and oxygen at higher temperatures. Had the wire alloy contained osmium I would say that it was OsO4 you smelled.
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Pulverulescent
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Whew, Os04 isn't something I'd want any contact with, not_important! IIRC, most compounds of Osmium are toxic and the tetroxide highly toxic. And,
yes, gaseous oxidisers have similar odours but I encountered ozone long before getting my hands on HN03. The name Osmium comes from the same root as
that of ozone; I think Osmium means "bad smelling".
As I said earlier, I have a thing about ozone; it's interested me since I was a child, because I could never get my head around the fact that
electrical sparking should produce such a unique smell.
I have even smelled it from the tiny disharges of a piezoelectric igniter. The lighter should be empty of gas, of course and twenty fast clicks might
be needed.
If you put your nose really close to the glass of a plasma-globe you'll notice the smell of ozone.
But, because of possible dangerous radiation it shouldn't be tried for extended periods. A few seconds, though, shouldn't hurt.
Sometimes, it's noticeable still, in car-exhausts despite the 3-way cats. There's N02 as well, but it's far more pungent than ozone.
I can't, at the moment, do anything practical, but when I can, I *will* get the equipment needed.
I intend getting to the bottom of it, at some time, whatever happens!
In the meantime, anyone interested enough can have all the details, as I remember them.
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12AX7
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Walking around my house, it's quite easy to tell when the furnace is running: the smell of oxidizer is irrefutable. This must be NO2, though ozone
and others have similar smells.
Tim
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Pulverulescent
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Are there, I wonder, any members who know how the NEMCA effect works?
I can get only abstracts (discrete bits of the puzzle) and it's not enough, obviously!
What I found particularly intriguing is the inference that it can lead to weak gas/metal bonding in oxygen chemisorbed on platinum.
The effect certainly seems to greatly increase catalyst activity of platinum in certain cases and weakly bound oxygen might be affected by electron
transference within the metal to a point where bond-breaking occurs.
I dunno, I'm clutching at straws here, but I don't buy the idea that reduction of metal oxides led to the evolution of ozone, I witnessed.
I don't know how Occam's razor would relate to this---I seem to be going for the most complex explanation possible.
Anyway, rules, like pie-crust, are made to be broken!
NEMCA seems to have implications for all catalytic and electrochemical reactions---fuel-cell research, too.
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Pulverulescent
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Tim, any ozone formed in your furnace would decompose, in situ; N02, being somewhat more stable can be noticed when it escapes the furnace.
If your furnace is working properly all exhaust gasses should exit by the flue.
I've breathed N02 when unavoidable but I wouldn't want it in my house for any length of time.
P
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Pulverulescent
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Incidentally, oxygen chemisorbed on platinum can be seen as an unstable, quasi-oxide, though I wouldn't carry the analogy too far.
Its desorption, subsequently, as a reduction.
P
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Pulverulescent
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Pardon the "Anglo-Saxon sporting terms" here, but, where in the fuck are the vociferous "geniuses" who were so active before my first ozone post?
Are they suffering paralysis, or are they so fucking precious they're afraid their hard-earned credibility will be compromised by associating
themselves with something new and challenging.
Do they think I'm attempting some kind of fraud, or what!
And, if it *is* a fraud, what, exactly, do they think is in it for me?
I found something which, if it can be made work, has potential to cut the cost of ozone to a fraction of its current energy prices, and no one has an
opinion on it, either way???
I've posted enough details already to show this isn't just some kind of wind-up!
Wake-up, for fuck's sake!
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Xenoid
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| Quote: | Originally posted by Pulverulescent
I've posted enough details already to show this isn't just some kind of wind-up!
Wake-up, for fuck's sake! |
Well, I would like to try it but I don't happen to have any Pt or Pt/Ir wire to heat up and possibly destroy. I don't think you are going to find any
other people on this forum with "wire to burn" either. With Pt prices approaching $2000 an ounce. it is hardly looking like a cheap method of making
ozone. It's a bit difficult to make any sort of comment on a procedure that only someone else has ever observed. What are we supposed to say! I think
your ideas are feasible, so many strange processes occur on or near the surfaces of Pt group metals.
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not_important
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Well, you've been tossing out explinations to an event that only you observed, analyzed with sub-optimal equipment (smell-test does not cut it as
proof of O3), and you out and out state you've not replicated it.
Then you inject an event you ascribe to the formation of aqua regia but heating NH4Cl in air in the presence of massive platinum alloy; while to me it
sounded like a classic case of "how to ruin platinum ware through alloying"
In both cases, as you said | Quote: | | I seem to be going for the most complex explanation possible. |
Your explanations for the event do seem to
be pushing the probable, invoking processes in conditions far outside their normal occurrence.
Replicate it with better control, and perform tests that show it's ozone, and you'll get more interest.
If I had platinum to toss about, I'd be more likely to look at this http://www.sciencedirect.com/science?_ob=ArticleURL&_udi...
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Pulverulescent
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I'm outa here!
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not_important
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The NEMCA effect(s) are related to the interaction of electrolytes, typically sold electrolytes, with the catalytic metal surface. Seems to have to
do with formation of O2- ions.
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indigofuzzy
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As for making Ozone electrochemically, I have accidentally produced ozone by running 12VDC through a solution of MgSO4 using Pb electrodes. After I
finish moving (again) I'll reconstruct the experiment and post about the results
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12AX7
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Yes, the Pb anodizes to PbO2, which usually flakes off easily. Electrolysis of sulfuric acid solution gives oxygen, hydrogen, PbO2 flakes (the lead
itself is eventually consumed), and if cold, persulfuric acid is produced with some efficiency. Further electrolysis gives even stronger oxidizers,
ozone being a side product. (It doesn't take much to smell, so the ozone efficiency can be immensely small -- millionths or less -- and still be
detected.)
Tim
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not_important
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Matter of fact
| Quote: | | The electrochemical synthesis of ozone is studied on lead dioxide electrodes in sulfuric acid solutions. The two maximums of the current efficiency
for ozone (CEO) observed at 2–3.5 V are largely due to the participation of various chemisorbed particles in the ozone synthesis. In the vicinity of
the first CEO maximum at lead dioxide, ozone forms only in a discharge of water molecules with the participation of adsorbed oxygen-containing
radicals. In the potential range of the second maximum, the adsorbed anion radicals, e.g., ·HSO4 and ·SO4, also take part in the reaction of ozone
generation. |
http://www.springerlink.com/content/c6750723p7018j12/
Electrolysis of sulfuric acid solution using a high current density and platinum electrodes has yielded oxygen with an ozone content of up to 25%
here's one old reference
http://books.google.com/books?id=wEoJAAAAIAAJ&pg=PA184&a...
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triggernum5
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I've been playing with HV ozone for a little while now.. The results from this thread have prompted me to reinvestigate the basic tubular
dielectrically separated electrodes..
The only convenient setup I've had to play with though was an 'as it was' 5" b/w TV flyback circuit from one of those Memorex karaoke machines.. (I
simply use the HV+, and various wires cut from the CRT's yoke)..
This is a PUNY POS flyback with recifier built right into it.. I don't know details on its output.. (I fried an old multimeter on it though, so that
should answer the question asked earlier about whether that is safe.)
This unit by itself will snap a spark at ~4mm, and that can be pulled to atleast 8mm before the streamer dies.. In my experience, the tube design
doesn't work, although I only had crappy plastic tubes of appropriate size (yea its pretty pathetic to be here, and not own a test tube ATM .. Anyways, I never got corona that way.. Depending on the config, it either
sparked, or seemed like way too much separation and did nothing.. I tried many wire types/sizes..
Two methods I tried produced a decent amount of various oxidizing gases.. Two sheetmetal plates separated by glass seemed to do nothing.. Then I
tried allowing the sheets to overhang the edge of the glass such that only air separated a small area of the 2 sheets, and voila, I got a blue glow
in the crevice crawling from one plate, across the glass edge, and to the other plate.. It gets really intense and smelly when hit by humid breath..
Surface area/Power must be an issue, because the gap size (as in the surface area separated by only air) was highly tunable.. (Btw, this is one nasty
capacitor, so always discharge!) The downfall is intermittent sparking when I try to maximize the corona, but with careful assembly that can be
nearly eliminated..
Another method I tried was positive pin corona.. This one is IMPRESSIVE but touchy.. I used an aluminum plate, and many unbraided 'fine' wires
fanned out where they were stripped (about 20 braided wires stripped), and positioned perpendicular to the negative plate.. (I found SS is more corona
prone than Cu btw).. The contraption was built into a plastic P Butter jar so the lid's threading could be used to adjust spacing.. Many streamers,
and tons of hissing, but again maximization is a nightmare since each of many strands needed be perfectly gapped, and decented fanned apart from its
sister strands.. In anycase, the best I ever did was ~30 good streamers without others sparking, but even a couple of streamers pump the O3 nicely..
I want to see how a fine brass brush works on the pin side since it may be ideal for calibration..
Negative pins is a whole different shebang.. Rather than streamers, the wire tips only emit corona dots.. Sparking is way less likely, but not as
much O3, and when a spark does occur its red/hot, and burns the wire strand.. (Unfortunately metal balls up at the tip which is poor for corona,
otherwise I'd use that aspect to evenly space the pins via burning..
Other downside to the sparking is that the EMP loves to crash my router etc..
I've collected quite a bit of literature on corona.. I'll try to collect it all into one place.. If I post a link to anything that may put the site
into a copyright delemma then I appologize.. I'm not entirely versed on site policy..
Anyways, as I dig them up I'll post them all in the same directory on my webserver (/scimasdness).. For now:
http://triggernum5.servebeer.com/scimadness/coronadischarge.... <-Very comprehensive, begins at basics, and even discusses driver circuits..
http://triggernum5.servebeer.com/scimadness/PositivePoint2Pl... A bit o' data..
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12AX7
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Well yeah, a dielectric generator won't work with a DC output. Obviously, it'll charge up. As you discovered, corona is the way to go with that, if
anything.
Tim
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triggernum5
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What I've got should be atleast as good as the cascade multiplier from that one link though, and the guy who posted that design claims decent output
.. Regardless though, I think the key to success with what I have would be finding the ideal inorganic film, whether it be an oxide or whatever to
spread out the charge.. I've read alot about porous dielectrics and 'back corona' for DC setups..
Another anecdotal observation is that finely corrogated cigarette tinfoil makes for a very good surface for supporting streamers without the
propensity to spark..
Too bad the internet put my local electronics shop out of business.. I just don't seem to possess the drive to order the materials I'd need to make a
kickin' flyback.. Could fluoresent ballasts in series be useful perhaps? Probably dangerous, but it would never be unattended..
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Natures Natrium
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I was wondering if I could get a critique on this schematic I adopted for use as a power supply in an ozone generator.
Original, Fly-back based design:
Crappy Schematic:
Attempt to create board traces:
The estimated 960V DC is being fed by a 120V, 1-6A AC --6:1 step up transformer--> ~720V AC --Full wave 1-Phase bridge recitifier rated @ 1200V,
35A--> ~960V DC.
The idea of this scheme is to create a power supply in which both the frequency and the ampreage can be controlled. In this case, the supposed ideal
is roughly 30kV, 10mA, 18-22kHZ. This is based both on the yet-to-be constructed ozonators design and also several scientific papers on the
production of ozone.
Please feel free to point out any and all flaws, and if the knowledgeable would be so kind as to explain a solution for those flaws, I would be most
grateful.
My sincere thanks,
Natures Natrium
\"The man who does not read good books has no advantage over the man who cannot read them.\" - Mark Twain (1835-1910)
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12AX7
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Your PCB shows no ground return and, I suspect, blatantly incorrect pinout on the IGBT. The voltages suggested are utterly absurd: not only is 960VDC
far too close to 1200V (think factor of two headroom, minimum!), it has absolutely no room for the flyback pulse, which I assume is the whole point of
this driver.
Why screw up IGBT gate drive with a single transistor? The 555's pin 3 will drive the gate about ten times harder than as shown! A 10 ohm gate
resistor also seems optimistic; 100 ohms would be more inline with a 555's output capacity. If you want to drive it properly, use a complementary
emitter follower (in which case, 2N4401/3's or better will drive the gate hard enough to warrant a 10 ohm resistor) or a purpose-made gate drive chip
(well bypassed, of course, as these typically output several amperes peak!).
If you aren't very good at electronics, you would be much better off using an NST. The voltage and current is right and you don't have to do
anything, just plug it in.
Tim
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Natures Natrium
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Thanks for the response, this is exactly the kind of info I was looking for. I did forget to include the ground returns on that rough pcb layout,
though I know where they both go. I wasnt aware that ibgts/rectifiers needed so much headroom, but glancing at my spec sheet I see that 1200 is
listed as the breakdown voltage. I suppose that 480V-640V would be ok, I would just have to change the final step up transformer to 64:1. Not real
sure I could wrap a decent enough one by hand to get a high K coupling at that ratio.
Also, there is not going to be a flyback involved, and this is not intended for use in a tesla either. Its going to be strictly used for corona
formation across a dielectric. As much as possible I dont want the secondary to shunt back onto the primary.
As far as the gate on the IBGT goes, I think you're right. The gate threshhold voltage is 3.75-5.75V, and I think it is saying 250uA on the
collector. Hmm, I will upload the PDF so anyone can gander at it if they wish. Anyways, the LM555 produces a high voltage of 15V at 100-200mA, so I
guess that would be enough to drive the IBGT.
As far as the pins go, I didnt really label them on the pcb. The gate is definetly middle though, and in this case the emitter would be "north" of
it.
I have a 10kV, 30mA NST, and it definetly does not suffice for my needs. I need a power supply that I can vary the overall power levels on, and more
importantly that either voltage or amps is the ability to vary the frequency, as that has a strong impact on the production of ozone through corona
discharge.
Im undoubtably a newbie at electronics, but there is no way in hell thats gonna stop me or slow me down. I never expect to be a master electrician,
but I intend to build a useful and pragmatic library of knowledge nonetheless.
thanks,
Natures Natrium
\"The man who does not read good books has no advantage over the man who cannot read them.\" - Mark Twain (1835-1910)
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12AX7
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| Quote: | Originally posted by Natures Natrium
glancing at my spec sheet I see that 1200 is listed as the breakdown voltage. I suppose that 480V-640V would be ok, I would just have to change the
final step up transformer to 64:1. |
Still far too close. Try 300V. As you have drawn it, you have either a half wave forward converter or a flyback converter. No ifs, ands or buts,
this is all it can ever be. As such, you must have headroom of at least, say, double the supply voltage, and another factor of 2 on top of that for
the transistor itself. High voltage flyback circuits often reach higher ratios, say 5 or 10 times. Obviously, a 1kV transistor will be at its limit
from even a +100V supply if it has such a ratio. (BTW, the flybacks in most monitors are ran at a duty cycle around 85%, supplied around 100VDC, and
switched with 1.5kV bipolar power transistors.)
| Quote: | | Not real sure I could wrap a decent enough one by hand to get a high K coupling at that ratio. |
You're a whole lot more insane than I am! Why would you want to wind a high voltage transformer when you can get one off the shelf?
| Quote: | | As far as the gate on the IBGT goes, I think you're right. The gate threshhold voltage is 3.75-5.75V, and I think it is saying 250uA on the
collector. |
You need at least 10V to turn it on fully. 10-15V is fine. A 555 will swing its output to within a volt or two of +V, so a 12-15V supply would also
be fine.
| Quote: | | As far as the pins go, I didnt really label them on the pcb. The gate is definetly middle though, and in this case the emitter would be "north" of
it. |
That's odd, I have *never* seen an IGBT, MOSFET, or for that matter any power transistor, not pinned G, C, E or G, D, S or B, C E (respectively).
Tim
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7he3ngineer
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| Quote: | | If you aren't very good at electronics, you would be much better off using an NST |
...Ok Tim, we've all seen what your like at electronics, with your knowledge/ experience, what would be your preference, the custom ozone generator or
the NST.
What advantages would you see in building a custom circuit?
Josh
BTW I know this belongs in the relevant thread (Axehandle's), but I'm posting now...found this the other day:
http://youtube.com/watch?v=_bUYPAe2fXc
Engineers aren\'t boring people, we\'re just interested in boring things!
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Natures Natrium
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Hmm, but the bridge rectifier is full wave, so shouldnt it be a steady stream of slightly rough DC? Oh, the bridge recitifier is not on the pcb,
maybe thats a possible misunderstanding? Perhaps there is something fundamental I am missing here, but I dont understand how switching DC on/off to a
step-up transformer constitutes a half-wave... unless both the positive and negative sides of the DC need to have a turn at the primary of the
transformer? Either I just stumbled onto one of my mistakes or I have made yet another.
As for buying the hV step-up trans, well, I am one of those people who wants to "do-it-themselves", to a fault. However, you make a good point, it is
at least worth looking in to.
Aaaand, you were right about the pins on the IBGT. I will actually include the pdf file this time, and sure enough the gate is pin 1. A stupid,
plebeian mistake for sure.
300V DC is kinda crappy though, surely there must be a way to get more mileage out of these 1200V rated parts.
BTW, your help here has been invaluable, many thanks.
NN
Attachment: IGBT.pdf (304kB)
This file has been downloaded 981 times
\"The man who does not read good books has no advantage over the man who cannot read them.\" - Mark Twain (1835-1910)
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