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Ozone Generator Finished

VisibleGreen

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Re: Ozone Generator (WIP)

Only at concentrations that would irritate the lungs pretty quickly. =P

So probably best to set it and leave the house then come home to a fresh and clean house :D
 



Cyparagon

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Re: Ozone Generator (WIP)

So probably best to set it and leave the house then come home to a fresh and clean house :D

The half-life is about 30 minutes. That means if there are 10g already in the air, 5 grams are lost per half hour, and 5 grams are added by the device per half hour. 10g is not enough to have much effect if it is distributed through a whole house. ozone isn't a very good "air cleaner" anyway (it just tends to convert bad things to different bad things), and even if it was, the irritation and hazards to lungs alone would make it nonviable.
 

Sigurthr

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Re: Ozone Generator (WIP)

Ozone is best for personal enjoyment of "non"hazardous levels by HV junkies. Beyond that it works fairly well when combined with a strong 254nm LPHg source for per-incident elimination of VOCs in uninhabited spaces. As I mentioned earlier the 254nm accelerates the disassociation of O3 into O2 and O-singlet, which accelerates the oxidation of VOCs, in addition to the direct action of 254nm on VOCs. If the VOC content is high it does leave a residual "burnt hair" smell when a strong 254nm source is used but that dissipates quickly and isn't very intense. To be clear though, it doesn't really "clean" the air as Cyp points out, it just transmutes smelly VOCs to less smelly OCs.
 

jeffreythe00

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Re: Ozone Generator (WIP)

Water purification is a really good use for ozone. Take some nasty colored water, bubble some ozone through and it should clear up in about 15 mins. I don't know the exact science behind it but it works similarly to bleach.
 
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Sigurthr

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Re: Ozone Generator (WIP)

Hey 00Jeff! You're right I totally glossed over the water purification application. I forgot about that. I still think spraying an atomized/fine mist of the water to be cleaned through a chamber filled with ozone is far better than bubbling, but the method hasn't seemed to catch on commercially for some reason.
 

Sigurthr

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Re: Ozone Generator (WIP)

Yep, singlet O attacks iron pretty readily. Many common other metals form passivating layers though, primarily Aluminium for example. However, the passivation doesn't protect from the HNO3 vapors produced as a byproduct though, so even passivated metals will see corrosion given the right conditions.
 

Sigurthr

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Very nice! I bet it kicks out some serious ozone!

Related to your build I recently got my hands on a MQ-131 Gaseous Ozone Sensor. I spent about a day and a half playing around with it, only to find it is not nearly as sensitive as I was hoping it would be. It is labeled on most english datasheets as being a 10ppb to 1ppm sensor, but in other chinese only datasheets it lists the true values; 10ppm to 1ppt.

I ran my small TC for about an hour to get the ozone up to where it was getting nearly uncomfortably strong and it barely registered on the sensor. I thought maybe the super fine and dense mesh covering the sensor wasn't letting air diffuse through well enough so I placed a small DC fan near it, and the readings increased greatly. Unfortunately repeating this when there was no ozone present caused a similar, albeit less intense, increase in output. This leads me to believe the increased airflow caused thermal drift to the heating element which resulted in the increased output, not the increased availability of ozone.

For reference; most people can detect ozone well at around 10ppb. At around 30-50ppb the odor stops being pleasant for continued exposure to most (a quick whiff usually doesn't upset at this concentration). Above 50ppb the smell gets irritating. I estimate I had the room around 100-200ppb when I got the barely registerable reading. This corresponds with the lowest point the sensitivity:eek:utput curve would show on the chinese datasheet if the curve data was extended fully to the origin and you interpolate between listed values.

What's interesting is I also got another sensor by the same company; the MQ-3 which detects volatile organics, particularly alcohols. The baseline reading in normal air is nearly twice that of the reading in an ozonated or UVC treated room. In a way this makes this sensor far better at detecting Ozone than the supposed ozone sensor! Likewise, it is very impressively sensitive to VOCs. 1-1-difluorethane causes a massive increase in readings from the MQ-3, even from across the room. Difluorethane is the propellant in "canned air" or electronics freeze sprays. I dusted my keyboard while coding up the interface for the sensor and was wondering a few minutes later why the sensor output quadrupled! I put on my UVC lamp and vacated the room, within about 20min the sensor reading was just barely above normal background levels. I repeated the test later on with Ozone from my TC and got similar results (albeit slower because my SSTC doesn't make a ton of ozone. I imagine a couple minutes from even a small SGTC would eradicate the VOCs in the room way faster).
 

ped

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Wouldn't mind one of those sensors myself.
Interesting the results you were getting when using a fan, could the rushing air (and increased dust particle flow) be causing static build up around the sensor?

Also, re reading Lux Nitida's post...I think I might use the unit like this...

Have the blower & UV lamps active permanently, and use the arduino to switch in the ozone generator once per day, while I'm in work, for say 5 minuets, as a kind of ozone "bomb" which should of dissipated by the time I get home.

Thoughts?

Ped
 
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Sigurthr

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Wouldn't mind one of those sensors myself.
Interesting the results you were getting when using a fan, could the rushing air (and increased dust particle flow) be causing static build up around the sensor?

Also, re reading Lux Nitida's post...I think I might use the unit like this...

Have the blower & UV lamps active permanently, and use the arduino to switch in the ozone generator once per day, while I'm in work, for say 5 minuets, as a kind of ozone "bomb" which should of dissipated by the time I get home.

Thoughts?

Ped

The MQ-131 (craptastic ozone) or the MQ-3 (superb VOC/alcohol & pseudo ozone/UV)? I recommend the MQ-3 highly, and it's only a couple quid from china via ebay. The 131 was ~20 quid and I still feel ripped off lol. The 131 is supposedly sensitive to halogens too, and I might give it a go with CL2 or I2 if I feel like it later. It's claimed to be sensitive to NOx, but initial tests with safe concentrations yield no results.

re: perm UV, ozone bombing; sounds good to me. The UV is largely contained and only the air is being exposed so it's pretty much safe to run forever.

I'd give the ozone cell a thermally limited burn time, not sure what that would be. My point being though that you want something on the order of minutes, not seconds, if the cell can thermally handle it. Ozone dissipates rather fast, especially if it has VOCs to attack or UVC to attack it. My 20W 254nm lamp blasts out the ~150ppb O3 within about 5min. Your little lamp will undoubtedly take long given geometrics and flow rates through the chamber, but you'll be gone hours, not minutes so it should balance out.

If you need me to modify the arduino code let me know, it should be an easy fix. I'm pretty sure I used integer for the variables so it would overflow after ~9hrs. It's an easy fix to change them to longs which would allow an interval of up to 68yrs, hehe. I just have to remember to put in the "L"s after the integers (bad habit of mine to forget them!). =P
 

ped

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I'd be super grateful if you could modify the code.
And yes you're right, the ozone plate gets hot during use, this becomes a problem after around 3-5 mins, hence the spacing around it in the enclosure. That being said, the blower shifts a lot of air over it and stops thermal runaway, its hot, then stays there.

Ped
 

Sigurthr

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Here ya go! I didn't test it out for obvious reasons, but it passes the compiler checks no problem and I didn't change any actual functionality (just made it so two variables don't overflow for such long time scales) so it should be fine.

Code:
/* Ped's Ozone Timer
 *  Written by Matt "Sigurthr" Giordano
 *  2016/1/23
 *  www.SigurthrEnterprises@blogspot.com
 *  SigurthrEnterprises@gmail.com
 *  This code only works when timeperiod > Ontime.
 *  
 *  Modified 2016-6-2 for once per day 5min-ON.
 *  Power the arduino (or hit reset) 5min before
 *  you want the device to turn on, and it will turn on
 *  again at roughly that time once a day. Right before
 *  leaving for work probably works best in this case.
 *  86400 is the number of seconds in 24hours. Add this
 *  to the ontime in seconds if you wish to keep it once
 *  per day but lower the ontime (if for example 5min 
 *  would overheat the ozone cell and you need 3min,
 *  you'd change it to ontime = 180; and  
 *  timeperiod = 86580; )
*/
unsigned long blinkerMillis = 0;
unsigned long currentMillis = 0;
unsigned long previousMillis = 0;
unsigned long highMillis = 0;
unsigned long ontime;
unsigned long timeperiod;
unsigned long onmillis;
unsigned long offmillis;

void setup() {
  pinMode(3, OUTPUT);
  pinMode(13, OUTPUT);
  digitalWrite(3, LOW);
  digitalWrite(13, LOW);
  ontime = 300;           // time in seconds to be ON
  timeperiod = 86700L;         // time in seconds to be ON + OFF
  onmillis = 1000L * ontime;
  offmillis = 1000L * timeperiod;
}

void loop() {
  currentMillis = millis();
  if (currentMillis >= blinkerMillis + 1000L){
    blinkerMillis = currentMillis;
    digitalWrite(13, HIGH); 
  }
  if (currentMillis >= previousMillis + offmillis) {
    previousMillis = currentMillis;
    highMillis = currentMillis;
    digitalWrite(3, HIGH);
  }
  if (currentMillis >= highMillis + onmillis){
    digitalWrite(3, LOW);
  }
  if (currentMillis >= blinkerMillis + 150L){
    digitalWrite(13, LOW); 
  }
  if (currentMillis < previousMillis){
    previousMillis = 0;    
  }
  if (currentMillis < blinkerMillis){
    blinkerMillis = 0;
  }
  if (currentMillis < highMillis){
    highMillis = 0;
  }
}
 
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ped

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Superb, thank you.

Will let you know in a couple of days if it worked :crackup:

Ped
 

Benm

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Re: Ozone Generator (WIP)

Water purification is a really good use for ozone. Take some nasty colored water, bubble some ozone through and it should clear up in about 15 mins. I don't know the exact science behind it but it works similarly to bleach.

The effect is very similar to that of non-chlorine bleach - i.e. substances that generate hydrogen peroxide which in turn decays into singlet oxygen.

Ozone can be very effective for removing smells including that of smoking in a room, but it should NEVER be used while you are actually IN the room. It's fairly commonly used to remove smells from things like hotel rooms, cars, rv's and such, but you need to ventilate them properly after an ozone treatment.

The levels used to remove odors are much greater that that bit of 'nice' ozone smell that comes off your laser printer or copier. If it is high enough to kill a nasty smell, it probably is high enough to kill you.
 

Teej

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As a guy who investigates environmental crimes/illegal emissions, etc...I can tell you that those air quality warnings, the ones where they say to stay indoors, or its ok to excercize outside, etc...rate one main thing: OZONE.

Its pretty irritating, as a strong oxidizer.

If you have electronics in the house (Its possible...) the contacts can become prematurely corroded for example. I have seen places that were treated with ozone to kill odors from smoke and/or hoarders, etc...and the home's fixtures and wiring then had to be replaced due to oxidation damage.

Rubber seals, and other oxidation damaged materials can also be prematurely aged, etc.

Even 50 ppb is enough to cause most people problems, and some people start having issues down around a 1/10 of that.

Most problems are acute...but some can be longer term due to reactions in your lungs, that then lead to problematic metabolites.


For odor elimination...yeah, camouflage more than cleaning...and, the reaction kinetics are such that the concentration needed to react with the moles of contaminant is similar...

That means that if the odor source is present at 1,000 ppm, so would the ozone, and so forth.


So, have fun, but play safe.

:D
 
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