| 摘要 |
Air inhaled into a respirator encounters an air guide positioned inside the face-piece of the respirator which acts as a baffle for the air. The passage between the two contains elongate ridges which are shaped to impede and direct the air and to maintain the spacing of the air guide relative to the face-piece. Because of this, the air guide and face-piece can be made symmetrical, with an air inlet canister and a secondary speech outlet module being applied, in either orientation, to laterally symmetrically disposed apertures in the face-piece. |
