new models of personal air purifiers

In one dept at work, a lady has some allergy, so she has to run this 'air purifier'. I went in there to do some work, and my eyes started burning. The ozone smell was awful. I told them that ozone is bad for you when it's this strong, and ozone is one of the bad components of smog. Later when I had some time, I did a web search for ozone and air purifiers, and I found that some of these supposedly air purifiers put out way too much ozone and pollute tha air. I suggest you check those out to find out more about the bad effects of breathing ozone.

As for piezo transformers, they seem to be a cheaper way of doing what has been done for more than a hundred years, with simply a lot of very thin wire and some iron for the core to wind it on. You can make tens of thousands of volts with a flyback and tripler.

Also some sellers make claims about their products that are unsubstantiated, such as their effectiveness in a large area. If you use one of these small devices in a small closed room, they may be effective, but if they're in a cubicle in a large room, it's doubtful they can be of any halp.

Reply to
Watson A.Name - "Watt Sun, th
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I'm curious whether anyone has dissected any of the latest version of personal air purifiers? They are also sold as usb port plug ins to purify the air near your computer...and, still others are sold to purify the air in your car. They are sometimes called negative ion generators and the sellers claim that breathing the ozone they produce is supposed to improve your health:>: They usually include 'piezo' in the title of the product.

"Piezo" comes from the method used to produce high voltage, which produces the ozone (or negative ions as the sellers like to put it). Piezo technology means piezotransformer or piezoelectric transformer or piezo transformer, they go by a few different names. I'm fascinated by these devices and want to learn more, especially regarding the drivers.

I was wondering whether anyone had taken any of these units apart or whether there are any websites dedicated to sharing information about these new technology high voltage generators?

M
Reply to
Mebart
[snip]

Not if you report them. IIRC, Ebay has some clause in their Terms of Use that says that the seller is not allowed to sell an item that breaks the law. Things like 'email leads', just another way of saying email addresses for spammers, are illegal, so some spammers are selling the service where you pay for so many email blasts, and the seller does the blasting. But it's still illegal if you go by the law(s) that say that it's illegal to 'blast' spam to recipients without giving them the ability to unsubscribe. Anyway, if these ozone devices are prohibited or confiscated based on some federal law, then if they are reported to Ebay and the report gives the law that is being broken, they should then shut down the auction.

For awhile at least, until the BOFH sellers find a way around it.

From my experience, I would say that after a few tens or hundreds of hours of operation the dust and pollution buildup reduces the resistance of the insulation, and causes the high voltage to drop to some ineffective level. Then it's necessary to clean the dust off, or else use higher power to overcome the resistive drop. In any case, it seems that low power has some serious drawbacks.

Reply to
Watson A.Name - "Watt Sun, th

Thanks for writing. I belong to the Indoor Air Quality mailing list and ozonec is a popular topic, so I'm fairly well versed in the ozone matter.

The short version is that no ozone level is safe-the EPA has stopped just short of this declaration because they have a mandate to keep the air clean and they can't admit that they aren't doing their mandated function:>:

I read all the ebay auctions for these devices, and they all have ozone sections, claiming that the units they sell only produce XX units of ozone.....but they leave out the part about the volume of air that the results are spec'd for. Obviously I can put a small ozone generator in a large auditorium and measure no increase in ozone. But leaving out the volume of the room where the results were obtained is like measuring the carbon monoxide output of an engine that's upwind of the measuring device...'nuff said.

Somehow though, people continue to pay for these things, so the auction prices never drop low enough for me to afford to buy any to dissect. As PTB said, "there is a sucker born every minute".

The Customs department confiscates these things as they catch them coming into the US, and the FDA shuts down sellers when they find them. But, small time sellers (such as ebay sellers) fly under the radar and seem to get away with it.

I'm interested in the driver circuit itself, which doesn't seem to be documented. I know about the constant current mode which varies the frequency of the driver in order to regulate the output current. I'm interested in ultra low power high voltage generation, so want something that is efficient and runs in constant voltage more (by fixed frequency operation at the resonant frequency, and by varying the sine wave input drive signal amplitude). I think driving it with a sine wave avoids the ZVS problem that plaques square wave input signal operation. As far as I know, this means 'I have to roll my own' driver.

My guess is that this is how the personal ozone generators operate, although they probably aren't as concerned with efficiency of the driver as I would be.

M

to sned a reeply via emall, use anonymousone aatt thedoghousemail ddoot ccomm ddoot ccomm

Reply to
Mebart

Somebody should put these guys together with the ozone hole freaks - maybe they'd average out. ;-P

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Cheers!
Rich
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Reply to
Rich The Newsgroup Wacko

ozone

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window to

Anything that's rubber gets destroyed by ozone. I can leave rubber bands around a few floppies, and a few months later they fall off, or worse yet, turn to mush. If I lived and worked out in the countryu the rubber bands might last for years.

Reply to
Watson A.Name - "Watt Sun, th

operate,

chain

But that (Cockcroft-Walton array) requires many rectifiers and capacitors. To see a schematic of one go here and click on the link.

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m

It's much cheaper if you use a simpler method.

Reply to
Watson A.Name - "Watt Sun, th

I had a unit 20 years ago. Sold as an 'air purifier' and 'negative ion generator'. What it did was ionize dirt particles in the air, the particles then went looking for a place to ground themselves making a big ugly black blotch on a nearby wall. Well, the Air was cleaner.

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Luhan Monat: luhanis(at)yahoo(dot)com
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Reply to
Luhan Monat

Also, I used to repair TV's. They are great 'air purifiers' too.

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Luhan Monat: luhanis(at)yahoo(dot)com
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Reply to
Luhan Monat

They're a bit of a gimmick overall, but people will pay for them because it's hard to prove whether or not they do any good, and they do mostly at least filter the air which I suppose is better than nothing.

I have an ozone generator I built a while back which works well for deoderizing but it's certainly not something I'd want running all the time. I just put it in a room that's a bit smelly, plug it in, leave the room and shut the door, then a half hour or so later unplug it and open the window to air it out, does a nice job for that.

Reply to
James Sweet

You can very effectively generate ozone with a voltage multiplier chain connected directly to the AC mains, you just need a needle electrode.

Reply to
James Sweet

What's simpler? You can make a driver for a surplus flyback transformer, or use an oil burner ignition transformer if you can find one of those surplus, but a multiplier ladder is dirt cheap, I've bought diodes by the hundreds on ebay for a few dollars, and have seen many similar deals with capacitors. Should be able to get 5-6kv for 5-10 bucks with some scrounging.

Reply to
James Sweet

Plenty of ozone is created in the upper atmosphere by UV striking oxygen molecules, but high concentrations of chlorine up there will break it down as fast as it forms.

Reply to
James Sweet

So, tell me how chlorine, with a molecular weight of 71 (on average), miraculously levitates to the top of a sea of oxygen, with its molecular weight of 32, and nitrogen, with a molecular weight of 28?

Or better yet, Freon, which is so dense that it can be literally poured from one container into another?

And how is it that this chlorine and freon and all those other boogeyman gases happen to skip past the ozone that's polluting the cities, on their way to the south pole?

There's no ozone over the south pole because most of the year there's no sunlight there to make any.

Sigh. I lament the loss of science education these days.

Thanks, Rich

Reply to
Rich Grise

Your pulse: 98.6. Very scientific.

Quant Suff!

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The Pig Bladder from Uranus
Reply to
Pig Bladder

Which, of course, explains why the atmosphere has settled into layers of Nitrogen, Oxygen and Carbon Dioxide amoungst others ;) And of course water never rises higher than sea level.

Robert

Reply to
R Adsett

Water has a molecular weight of 18, of course it's going to rise. ;-)

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  Keith
Reply to
keith

Beg Pardon? An unusual dialect perhaps? I understand all the words but I can't make any sense out of the phrase.

Robert

Reply to
R Adsett

....not unusual.

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  Keith
Reply to
keith

A point, definitely a point. Yet somehow it falls back down again. ;)

Robert

Reply to
R Adsett

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