Exhaust Filter for 3M 7500 Series Respirators

thingiverse

Proper use of an elastomeric respirator in a medical setting requires that the exhaust port be filtered to prevent contamination/exposure from the user's exhaled breath. Due to the shape and location of the 7500 series' outflow port, placing a surgical mask over the port can be hit or miss, and I was unable to find an adapter design on Thingiverse that fit all my requirements, those being: 1. Large as possible filter area to reduce exhalation back-pressure (pops open the seal, becomes fatiguing for extended use, and makes communication even more challenging) 2. Maintain downward directed exhaust path to minimize potential exposure of the filter surface to droplets/spray, and to reduce fogging on a face shield after extended use 3. Low vertical and front profile to reduce collision with or protrusion from under a shield, or interference with head movement (i.e. looking down) 4. Easy replacement of filter media 5. Straightforward printing of replacement parts without needing supports, extensive post-processing, etc. The adapter design by tkworksd (https://www.thingiverse.com/thing:4202541) has the best fitting attachment that I have tried, but all of the compatible filter sections were too small for me to use comfortably; therefore I remixed it with a new 65 mm aperture, low profile filter box to fit my needs.