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Marvin
National Hazard
Posts: 995
Registered: 13-10-2002
Member Is Offline
Mood: No Mood
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Tacho,
Dont you just hate it when half a decade of helping people with chemistry gives you a patronizing tone. Doesnt it spoil all the fun when most people
you help dont bother looking up anything in a library, or even think about the problem logically?
We are lucky not to have either of such people here!
I'm a happy go lucky person with both the valueable gift and heavy burden of being never wrong. Ocasionally the universe makes mistakes, which
is where discrepancies come from, and when I talk to god *I* am the one answering *his* questions. Unfortunatly axehandle has not learned this yet
and its almost a shame to spoil the happy feeling he has from thinking he's seen a mistake. The sooner he does learn this however, the sooner he
can help you with the shrine.
axehandle,
The two methods avoid the same problem, but they are different. In passing current through the air at atmospheric pressure, the flow tends to
collapse so a single point on both electrodes and move within a very small volume of ionised gas. A spark, or arc. This is hot gas as a result, and
so the conditions are bad for production of ozone. What is needed for ozone is a low density of current through the air. In the corona method, a
very fine wire or sharp edge 'sprays' charge into the air by virtue of its high electric field gradient. This is constant over its length
and so long as certain voltages arnt exceeded for a given arangement, dielectric breakdown does not occur and sparks/arcs do not form. This is
electrically just a discharge tube connected to the power source and so can use DC, or AC, and power dissuptated is largly independant of the
frequency, if AC is used.
The classic silent discharge method uses electrodes that are insulated, usually by glass tubes. A spark or arc cannot form because the only current
flowing is that formed by induction on the surface of the insulator. The discharge is forced to be very low density, and is constant throughout the
surface area of the tubes. Unlike the corona wire though, electrically this is a discharge tube in series with a low value capacitor. DC cannot be
used and the power dissupted in the gas is proportional to the frequency of high voltage applied, and thus the frequency proportional to the maximum
acheievable formation of ozone.
The NST is usually rated much higher than a flyback circuit in terms of power, but a flyback circuit produces high voltage at 10's of kilohertz,
wheras a NST uses mains as its input directly and thus outputs at 50 or 60Hz typically, so while it is rated at much higher power, in the silient
discharge method the flyback circuit will usually produce a lot more ozone.
A flyback circuit has no advantage over a NST on the corona wire method.
Sand blasted glass might catalyse decomposition of the ozone.
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axehandle
Free Radical
Posts: 1065
Registered: 30-12-2003
Location: Sweden
Member Is Offline
Mood: horny
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Wellcome back axe!
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Thanks. It's good to be back, apart from the annoying fact that all the interesting stores are closed due to the easter holiday. I won't get
any Al tubing until Tuesday, sigh.
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I just found out that my marvinator is not good enough to make H2SO4. You don't have to live in fear anymore!
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If anything I'm sorry that it didn't work. I don't think of this as competition, but as an internationally distributed effort based on
cooperation.
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I burned about 3 grams of sulfur in a 100ml glass flask, in the output line of ozone, bubbling the result gas in water. pH only went to 5 after about
15 minutes. Guess is just sulfurous acid. Any decent ammount of sulfuric acid would make my 10ml of water have a much lower pH.
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Sounds correct. Pity. The method would probably work if using multiple powerful ozone generators using pure O2 as the input.
On the bright side, I'm going to use your fantastic salt thermostat for the exhaust heater. I'll tell you how it goes.
My PGP key, Fingerprint 5D96 E09E 365D 1867 2DF5 C2FE 4269 9C19 E079 CD35
\"Verbing nouns weirds the language!\"
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Tacho
National Hazard
Posts: 582
Registered: 5-12-2003
Member Is Offline
Mood: No Mood
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Marvin,
I don’t think it’s God you are talking to. But if you think it is, it’s OK. Remember how we started this thread? Wacko, mercury?...
See? It’s all right! You are among friends here. We are here to listen and understand! You can open yourself to us. Don’t worry about
being a bit old, we are not very young either! We can make you young at heart like us!
Your last post explained very well why we need AC for the usual glass made ozonizer (Siemens). I must warn anyone trying to built one that some
flybacks have built-in rectifiers. I must also tell that my flyback HV circuit can make a spark jump a 1,5 cm gap easily, so, I estimate the voltage
in 15kV(this is empirical, Marvin, don’t make a fuzz, ok?). Flyback circuits can be pushed way above that; read Sam Barros page linked in
previous post.
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