40MM NATO (RD40x1/7) to Milla EURMASK® ETNA (Bayonet) Series Filter Adapter

This prototype design for a 40MM NATO (RD40x1/7”) gas mask thread to Milla EURMASK® ETNA (bayonet version) series filter adapter. This adapter makes any RD40x1/7 threaded full face CBRN masks compatible with Milla EURMASK® ETNA series line of chemical, combination, and particle filter cartridges to help mitigate PPE shortages by expanding greater cross compatibility of respirators and filters to other manufacturer models.

Part Description:

40MM_NATO_TO_MILLA_EURMASK_ETNA_BAYONET_FILTER_ADAPTER_GEN1.stl
Initial model release.

Disclaimers/Risks:

1.) Use Proper Gaskets
It would appear that the EURMASK respirators have the bayonet geometry on the filter rather than respirator. Additionally, rather than the gasket or o-ring typically underneath the bayonet, the EURMASK gasket on the respirator side, please perform negative pressure test to ensure proper seal between adapter, the filter and mask.

2.) Perform Proper Negative Pressure Test
Follow SSPs established by your institution or workplace for further guidance. But in general, don your respirator, adjust straps till taught against face, ensuring no obstructions around the periphery of the seal against face either due from hair, facial hair, or otherwise. Exhale deeply. Cover all inhalation ports. (Typically, most full face or half face respirators have two filters, so cover those intake ports with your hands. If your running only one filter, ensure the opposite port has filter cap in place.) Now inhale deeply. The mask should suck tightly against your face without any air leakages. Re-test if adjustments are required at gasket/o-ring interfaces at the adapter.

3.) Use At Own Risk – Temporarily Solution Only Until Supply Chain Normalizes
3D printing materials are not resistant to many solvents, are water soluble, and degrade when exposed to chemicals, heat, and UV/sunlight. 3D printing this adapter is only a temporarily ad-hoc solution against biological contagions. In addition to using a properly calibrated 3D printer, due to tolerances of adapters, if possible perform hot nozzle pass on all exterior surfaces, to reduce surface porosity. Highly recommended users apply a thin layer of polyurethane clear coat on all exterior surfaces, spray or dip based methods, to help resiliency and durability for repeated sterilization and to reduce fomite transmission in printed infill layers. Once supply chains return to normal, users should purchase OEM OSHA/NIOSH/EN standard approved respirators, adapters and accessories for their institution and workplaces.

Dev. Notes:

5/06/2020 - Initial model release. In work, pending 3D printing community support for any fitment and model revisions.

Credits:

Thanks to drzejkopf for his Milla EURMASK® ETNA to DAR filter adapter design., I extrapolated off the geometry to obtain the opposite respirator/female side mating geometry.
https://www.thingiverse.com/thing:4318660