| 摘要 |
A breathing device for use by persons engaged in activities within an environment of sub-zero air temperatures. The temeprature and humidity of inhaled cold air is tempered and moderated by passing through a matrix of plates secured in an opening in the frontal area of the mask structure. Exhaled warm air is expelled in reverse flow over the same route through the matrix of plates. No valves or moving parts are involved in the operation of this device. This feature is unique and original relative to prior art which is employed in the design of patented devices of this type which I have identified during my search of this classification. All previously patented devices in this classification which I could discover required valves and separate air passages in their operation.
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