Abstract

Current face-mask filters do not capture all airborne contaminants.

Filtration properties of thin liquid layers was analyzed in the laboratory. These experiments furnished the requisite data for the design of a filter which could capture all airborne contaminants without hindering the rapid gas diffusion necessary for respiration.

The filter is almost 100% effective against all dust and aerosols, and is much less expensive and heavy than a cylinder of compressed air. The service life of the filter is approximately 30 minutes, after which time the cartridge containing the liquid must be replaced. The liquid itself may be purified and reused. The filter may be used in combination with other chemical vapour filters.

The Department of Defense has contracted an experimental study of the filter, including the validation of a prototype. Further research is under way to reduce the evaporation of the liquid film. The filtration process has been patented in several countries.