MiniAer Ozone producing air purifier teardown - Page 1
Forum section: electronics / general

author: CNe7532294
author_rank: Regular Contributor
timestamp: February 13, 2018, 08:39:12 pm
content: So yesterday a family member arrived from a conference of sorts held in Miami, FL, USA. She had brought home this "MiniAer" to me as a gift. Now I don't have the heart to tell her yet but I accepted it from her because ozone is a pollutant at ground level. Just because its good for mother earth doesn't mean its good for life in general. Well direct contact that is. There is a reason why its number 4 on the blue side of the funny looking chemical hazards diamond. Heck its 4 on all colors with an "OX" in white. It is a form of oxygen that is reactive towards basically a lot of things but hey it also does absorb harmful UV rays. Also what qualifies this as an air purifier is based on what I mentioned above. "doesn't mean its good for life in general". Ozone kills microorganisms as well. I'm thinking of re-purposing this as a sterilizing unit trapped in a containment box or just not using it if its too much of an environmental hazard. In the meantime I'm taking it apart. Before I do that anyone want to guess just whats inside of the unit? Manual gives some hints. I'll be back with more pictures.

author: tooki
author_rank: Super Contributor
timestamp: February 13, 2018, 09:22:36 pm
content: I bet it’s just a simple ionizer with a fan.

author: Cyberdragon
author_rank: Super Contributor
timestamp: February 13, 2018, 11:02:39 pm
content: A switching supply powering a controller and fan driver, and an HV winding on the transformer going to a diode-capacitor multiplier. The setting might just control the fan or modulate the HV somehow (doubt it though).

author: CNe7532294
author_rank: Regular Contributor
timestamp: February 13, 2018, 11:41:15 pm
content: You're both on the right track. I had a peek inside. Just waiting till I come back from something tonight to send photos. Another thing. This doesn't convert oxygen only. Remember it uses surrounding air. 78% diatomic Nitrogen and 21% Oxygen with trace amounts of other elements. So I had fun being nauseated yesterday doing kill-a-watt measurements. My heart felt weird on top of that. I hear Nitrogen Monoxide is good on that. Also probably had nitric acid in my lungs. Fun stuff! And this is supposed to be good for me?!I feel sorry for her getting 2 pieces of this crap.At least she got them for free.

author: amyk
author_rank: Super Contributor
timestamp: February 14, 2018, 03:02:56 am
content: I suspect you're just overreacting. Ionisers like don't produce enough ozone to be much of a hazard unless you deliberately concentrate and inhale their output continuously. bigclivedotcom has done a series of videos on them.

author: CNe7532294
author_rank: Regular Contributor
timestamp: February 14, 2018, 04:48:22 am
content: Quote from: amyk on February 14, 2018, 03:02:56 amProbably. In a big room its not even noticable. Not to mention the same chemicals can form during arc welding and plasma cutting. Currently, the EPA acknowledges this device yet hasn't take any action or stance against this. As for the FDA, they just seem to defer to the EPA's set guidelines of ozone exposure along with what I'm interested in. Turning this device into some sort of sterilizer in a box. They made the conclusion that its not effective unless it kills pets and people.https://www.epa.gov/indoor-air-quality-iaq/ozone-generators-are-sold-air-cleaners#conclusionshttps://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=801.415However, I'm following as recommended as per manual. "Applications" - Small Bathroom I can tell you that I did feel funny in the head today as well. I also got the same feeling of somethings weird with my heart. Perhaps I'm over sensitive. I'm still worried though. I have a pet as well. Anyways shifting from health, onto the electrical aspect of this device.Specs as per manual seen:Input Voltage: 110-240Vac (measured 121.5Vac for my outlet)"Rated Powers": <5 (sparkles? measured 5.6VA and 2.2W)Power Factor: (not provided by manual but measured .4)Amps: (not provided by manual but ~40mA could be 45-46mA)Ozone output: 70mg/hr (I need to borrow a meter for ozone measurements)Ozone Creation: Corona DischargeCorona Discharge is the pink in the image. The blue light is just a LED to make it look cool? I assume. Next after this post is the teardown itself.

author: CNe7532294
author_rank: Regular Contributor
timestamp: February 14, 2018, 04:59:39 am
content: To note: There are no electrical certification markings like UL, CE, etc. Now for 40mA at 122V maybe those wires are acceptable? What I do find unacceptable is that the fan's wires can come into contact with the exposed solder end or the main's prongs. Isolating the hot side to the low voltage side of the power supply basically boils down to the insulation of the fan's wires. Other than that I took out the circuit board. Isolation is not as bad on the board. Next post is the board taken out.

author: CNe7532294
author_rank: Regular Contributor
timestamp: February 14, 2018, 05:18:00 am
content: Unit's main's plug sideUnit's front facing sideFinal post of pictures for now. You can see the huge isolation slots for the high voltage discharge side. You can also see how this protects the low voltage side. The separation between mains and low voltage maybe be hard to make out but it is there. Not sure if it is enough though. Might have to upload a MS paint edit tracing this out. So far at a glance, the components (fuse, caps, etc) seen meet the specs listed for 240V on the hot side. On the low side, they lasered out the IC (U1) that is the brains of the unit.

author: helius
author_rank: Super Contributor
timestamp: February 14, 2018, 05:52:05 am
content: I suspect you are experiencing a nocebo effect. The effect of ozone at levels like that is a specific metallic smell and irritation of the nasal passages. It does not cause heart problems in my experience. Many offices and homes contain quite effective ozone generators in the form of laser printers and copiers. Nitrogen oxides require high temperatures to form, not just electrical discharge.As far as electrical safety, they did use a lot of slots in the PCB, but those inlet wires are not double insulated, and the exposed solder joints are also a bad idea.

author: CNe7532294
author_rank: Regular Contributor
timestamp: February 14, 2018, 04:48:45 pm
content: Quote from: amyk on February 14, 2018, 03:02:56 am+1 for the bigclivedotcom vid. Watched it. Link here:Quote from: helius on February 14, 2018, 05:52:05 amNocebo effect is a possibility. Still, it felt so real. While you're correct that many xerox machines have generated ozone, I have smelled this metallic smell in the office and as early as my childhood in school, they're located in large open spaces. Plus I'm not standing all day next to the copier so I don't get this effect at the office. I should probably add that I installed this unit in a half bath (small bathroom with one toilet and one sink). I'll have to measure the space and compare to ozone output spec and EPA guidelines. Maybe the concentration got too high and no I'm not talking about farts either.Electrical wise I'd agree the PCB is well designed maybe some spots are questionable (I have to upload edited pic above later highlighting this) but it would pass. As far as the mains wires, I thought the same thing too but I just saw bigclivedotcom's vid. His unit had the same problem and it was CE listed. Pause vid here:https://youtu.be/STkMRTNDEFk?t=5m49sIn the meantime, found U2's datasheet. Its the 8 pin IC surrounded by slots.http://www.dkpower.cn/upload/201501/06/201501061555229531.pdf