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| engineheat:
--- Quote from: Halcyon on August 11, 2021, 10:55:48 pm --- --- Quote from: engineheat on August 11, 2021, 03:54:16 pm ---Do you know if the Dyson HEPA filter contains fiberglass? I heard those with fiberglass can leak fiberglass fibers. --- End quote --- It appears so. According to their website the PM filter material is made from borosilicate microfibres. I'd say it's not unlike a lot of filter material. I'm sure they've done their homework. I've never heard of the filters breaking down in such a way that would cause them to impart impurities into the air. Maybe some cheap filters from China of dubious quality would do that? I'd say if you're buying an expensive filtration device, you should also be buying the genuine filters. $100 per unit every 6-12 months is hardly a lot of money. --- End quote --- I've read that even "good" HEPA filters will release a bit of fiberglass fibers, especially when new: https://smartairfilters.com/en/blog/hepa-air-filter-fiber-harmful-health/#:~:text=Bottom%20line%3A%20HEPA%20filters%20shed,other%20dust%20in%20the%20air. That's why I'm looking at Filtrete filters as those don't contain fiberglass. |
| engineheat:
--- Quote from: NiHaoMike on August 12, 2021, 05:18:19 am --- --- Quote from: engineheat on August 11, 2021, 03:57:53 pm ---What does "director vanes" mean? Thanks --- End quote --- Those are stationary vanes that direct the air to come out exactly perpendicular to the fan itself, converting the spin imparted by the blades into more static pressure. Here's an example of a fan with them: https://www.newegg.com/p/1YF-00B0-00JW6?Item=9SIAAESD2T6194&Description=120mm%20delta%20fan&cm_re=120mm_delta%20fan-_-9SIAAESD2T6194-_-Product&cm_sp=SP-_-518473-_-0-_-1-_-9SIAAESD2T6194-_-120mm%20delta%20fan-_-120mm|delta|fan-_-12 --- End quote --- Thanks. After doing some research, it seems what I need is a centrifugal fan with forward-curved blade with single inlet, like this: https://www.ebmpapst.com/de/en/campaigns/product-campaigns/centrifugal-fans/forward-curved-centrifugal-fan.html I believe this can generate enough air pressure for HEPA filters. The HEPA filters I'm interested in have larger areas than the outlet opening of the fans that I'm interested in. I can build a "funnel-like" duct to mate the fan opening to the filter with very little air leakage. Would that decrease the air pressure to the filter? I don't think so since whatever air pressure generated by the fan should be uniform in the duct, but just to make sure... Thanks |
| Halcyon:
--- Quote from: engineheat on August 13, 2021, 04:06:03 pm --- --- Quote from: Halcyon on August 11, 2021, 10:55:48 pm --- --- Quote from: engineheat on August 11, 2021, 03:54:16 pm ---Do you know if the Dyson HEPA filter contains fiberglass? I heard those with fiberglass can leak fiberglass fibers. --- End quote --- It appears so. According to their website the PM filter material is made from borosilicate microfibres. I'd say it's not unlike a lot of filter material. I'm sure they've done their homework. I've never heard of the filters breaking down in such a way that would cause them to impart impurities into the air. Maybe some cheap filters from China of dubious quality would do that? I'd say if you're buying an expensive filtration device, you should also be buying the genuine filters. $100 per unit every 6-12 months is hardly a lot of money. --- End quote --- I've read that even "good" HEPA filters will release a bit of fiberglass fibers, especially when new: https://smartairfilters.com/en/blog/hepa-air-filter-fiber-harmful-health/#:~:text=Bottom%20line%3A%20HEPA%20filters%20shed,other%20dust%20in%20the%20air. That's why I'm looking at Filtrete filters as those don't contain fiberglass. --- End quote --- I'm not saying it doesn't happen at all (since I haven't looked into it properly), but as Dave would say, "I smell bullshit". A lot of this so-called advice seems to come from websites and companies who sell non-fibreglass filters. Of course they are going to say the competitors product is bad. Instil fear into consumer then offer an alternate "remedy" (at a price). Surprise surprise, the website you linked sells their smallest HEPA filters at the rip-off price of USD$180 (also no mention anywhere of them being free of fibreglass either). Fibreglass-based HEPA filters have been around for a long time yet this "problem" isn't a problem. You can bet that if it was a real problem, customers would be up in arms about it, demanding bans on these types of filters etc... etc... As I said, you have very large companies with very large R&D budgets whose job it is to research and test this stuff. Why haven't they found this shedding of fibreglass filters to cause any problems? After a quick Google, the only reputable source for fibreglass versus synthetic media comparison comes from a peer-reviewed paper from Clemson University (link). It talks about health concerns regarding fibreglass filters and concluded that the analyses show that both types of filter shed fibers, with some of them being respirable. Also the difference in fiber shedding between the two filter media is insignificant. The test results also show that fibers shed from the media decrease with time. As compared to the contaminate particles present in ambient air, the number of fibers shed by the filter media is negligible. The vast majority of other search results were advertisements or opinion pieces at best. There have also been numerous studies which show no relationship between the inhaled fibreglass and lung disease (asbestos fibres are obviously quite different). After crawling around in my roof cavity for an hour, I'd inhale more fibreglass and other particulates compared to a lifetime of using fibreglass-based filter materials. Personally, I wouldn't worry. The crap that a good air filter pulls out of the air is far more harmful to your health (by comparison). |
| SteveyG:
The Xiaomi purifiers seem to be working excellently here - I ended up buying a couple, the smaller one I use in the lab and within a few seconds of doing some soldering it picks up the reduced air quality and whizzes into action despite being 5 meters away. The filters last between 6 and 12 months, and although they have an RFID tag in to log the usage, you can carry on using them even if they're "expired". You can also use compatible filters which don't have the RFID tag. They're also very nicely built and well priced. |
| engineheat:
FYI, Filtrete filters are HEPA and are not made out of fiberglass. They are made out of polypropylene material. (I specifically asked their tech support). I'd think polypropylene might be a bit "safer" than fiberglass relatively, but who knows. |
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