Building a DIY PAPR but the fan has odor - Page 1
Forum section: electronics / beginners

author: engineheat
author_rank: Frequent Contributor
timestamp: May 06, 2024, 02:13:48 am
content: Hi,I tried building a DIY powered respirator using a 12V DC blower like shown below:I used an Arduino to control the fan speed via PWM, and I build a housing for the fan and filter. It works and the air flow is sufficient. My only problem is that the fan has an chemical/plasticky odor. This causes the air to also smell. I don't think it's due to overheating because even a newly arrived fan has an odor from the outlet, even when powered off. So I'm wondering if this is normal for fans like that? The smell seems to be coming from the stator/winding because I broke apart a non-used fan.Perhaps the fans I got isn't really suitable for this purpose. Can anyone recommend a more suitable fan for this usage? I wonder what type of fans are used in commercial PAPRs.Please advise.Thanks

author: Rick Law
author_rank: Super Contributor
timestamp: May 06, 2024, 06:22:40 pm
content: Quote from: engineheat on May 06, 2024, 02:13:48 amHow about just running it at various speed for a period of time, see if it start to reduce. If so, run it even longer until it is reduced to a point where it is hardly noticeable.This can also serve as "burn-in" period to test the fan's reliability prior to really doing more work on it.Edit: grammar correction, changed "until it reduced" to "until it is reduced"

author: Manul
author_rank: Super Contributor
timestamp: May 06, 2024, 06:40:16 pm
content: Try to deodorize with ozone maybe?

author: Coordonnée_chromatique
author_rank: Frequent Contributor
timestamp: May 06, 2024, 06:40:57 pm
content: https://www.mouser.com/catalog/additional/EBM_Papst_RV45_Whitepaper.pdf?_gl=1

author: CaptDon
author_rank: Super Contributor
timestamp: May 07, 2024, 01:12:29 pm
content: Wouldn't ozone tend to decompose the plastic and other components thereby increasing any and all oders? Guessing because the fan uses electronics instead of brushes / commutator it may have a 'circuit board' smell or is it A.C. line operated and the windings have a varnish smell? Sounds like a poor quality fan although it was never intended as a supplier of breathing air directly. Can't say I have ever run into a fan with objectionable smell induced into the airflow.

author: BrokenYugo
author_rank: Super Contributor
timestamp: May 08, 2024, 01:20:52 pm
content: The way I built mine the filter lives in a can (same plastic canister the NATO thread CRBN filter came in) pressurized by the fan, so the fan only handles dirty air and the clean side is all positive pressure. I used a cheap 12V air mattress inflator running on 5V to slow it down, which also forces the design because the motor is cooled by bypassing the intake some, so using it to pull air through a filter would be useless anyway.If you're making the mask yourself make sure the vent is bigger than the air feed, you want very little positive pressure in the mask/hood, more of a flow thing, airflow should exceed that of a sharp inhale. Rather than a real valve I just shoved a hose down my shirt, free extra cooling!These days I'd probably just buy one if I had a legit application for it, you couldn't really get one at any price when I built that.With a motor in the airflow it had better be an EC motor or you're breathing brushes and ozone from it.