Elipse Respirator clip-on exhale filter

prusaprinters

This is a clip-on cover for an Elipse P100 respirator to add outflow filtering using a piece of surgical mask.  The GVS SPR457 is a valved respirator with no outflow filtering.  This respirator protects its wearer from atmospheric and biologic contaminants, but it doesn't protect anyone else from any pathogens the wearer may carry.  IE it has no source control.  There is also an Elipse respirator version (GVS SPR644) which removes the values and passes all air, inhale & exhale, through the filters, providing source control at the expense of shortened filter life and more back pressure when exhaling.This part allows adding a form of source control to the valued version of the respirator when you need or want it, at the cost of increased back pressure while exhaling but with no effect on filter lifetime, since exhaled air isn't passed back through the main filters.  It can be easily removed and kept in a pocket, applied in situations where others choose to mask to keep themselves safe and removed when outside or in environments where source control isn't an expectation.Two use it, print both pieces (I used PLA, 0.2 mm layers, no supports necessary).  Use a sharp knife to cut out a circular piece of three-layer surgical mask, 3-4mm larger than the retaining ring.  Flatten the mask out to remove all pleats before cutting.  Sandwich the mask between the main body and push the retaining ring in to hold it in place, pinching the mask material between the two pieces.  It's necessary to poke four small holes in the mask to pass the four hooks which attach to the mask.  The effect of these holes on filtration should be minimal, all things considered.This design is based on an original by nygren on Thingiverse which was intended as a filler cover for the source-control version of the respirator.  That version was intended to provide some comfort to others who may have seen the respirator and thought it was NOT source control, since the source control version still has the same exhale port on the outside, just with a plug on the inside preventing any air from escaping.  That design is CC-BY-NC-SA. This design is also CC-BY-NC-SA 4.0.Disclaimer:  I'm a software nerd, not a virologist.  Use at your own risk, no guarantees of any kind are made.  It seems reasonable to conclude that passing exhaled air through a piece of surgical mask is safer for others than not doing so, but I'm wholly unqualified to provide any scientific support of that belief.