Closed circuit respirator with low breathing-out resistance - has heat exchanger in breathing tube fitted between mask and valve assemblies

摘要

The purpose of the design is to produce a closed circuit-type respirator supplying the wearer with cooled-down re-generated air at a reduced breathing out resistance. The respirator consists of mask part fitted with breathing tube in which the heat exchanger is mounted. The outlet end of the heat exchanger connects to a T-piece in which aspiration valve and discharge valve are mounted. During the breathing out cycle air is flowing through the heat exchanger and the valve into the breathing bag, while the relatively low resistance of the heat exchanger and the valve have to be overcome. The relatively higher resistance of the regenerative cartridge is overcome by the built-up pressure in the bag, while the cartridge is passed through by the air stream in one direction only.