Closed loop air filtration based on EN148 filters

thingiverse

As I print extensively, I sought a solution to maintain healthy conditions. I print a lot of ABS, which emits fumes and fine dust - both hazardous substances that shouldn't be inhaled. I opted for EN148 filters because they're designed to protect our lungs when used in their standard setup (attach these to face masks, when spray painting, brazing, etc.). I didn't have extensive equipment to test this but: When using dimafix spray for bed adhesion, TVOC values (measured by my air quality meter) skyrocket inside the printer enclosure. With a double P3 filter for particles and an AX filter for gases, I was able to lower tvoc to almost normal levels. Since the filter can accomplish this, I assume the fine dust is also filtered out - although I'm not certain as I don't have a reliable fine dust meter. I actually possess two of these, one being dual P3 + AX and the other dual P3 + A2B2. This setup allows for maximum filtration, and I'm fairly confident in its effectiveness. However, do note that to achieve some airflow over the filters, you'll need a fan with high static pressure - not those designed for pc cases. I tried several fans and only the Sanyo Denki San Ace 9HV0812P1G001 was capable of producing any flow. Keep in mind that the holes for the wires should be sealed, which I achieved using Super glue. This caused a white effect on the ABS (see picture). I had a PWM circuit for it but wouldn't bother with that - they need to run at full speed to be effective. The entire setup is assembled with M4 threaded rods, nuts, and washers. Some notable observations: Dust consistently stuck to my hot end fan, which is much less the case with these filters in place. Having filters on both sides of the fan significantly decreases noise levels. I experienced best performance with the P3 before the fan, then blowing air over the gas filter. The whole setup is loud, not extremely loud but still - it may be too loud for a desktop printer situation (it can be distracting). Sprays for bed adhesion aren't very healthy tvoc-wise, so be sure to read the instructions. Any questions or remarks, please ask. Make sure you read this: http://pubs.acs.org/doi/abs/10.1021/acs.est.5b04983. I also want to thank Brent Stephens and many others for helping me develop a working solution.