| 摘要 |
The described protection mask (1) comprises an annular lip (2) supporting a transparent screen (4) of toroidal form extending from the forehead of a user (3) to his chin. The screen (4) close to the user's mouth exhibits a preferably projecting middle portion (4c) having a connecting sleeve (5) provided with an inspiration opening (5b) and an expiration opening (5a) with which a single-acting valve (8) is associated, sealingly fastened thereto. A half-mask (6) is engaged to the inner part of the mask (1) and it sealingly acts by its perimetrical edge (6a) around the user's nose and mouth to bring them directly into communication with the expiration opening (5a). Two check valves (7) are associated with the half-mask (6) and are designed to enable the air transfer from the mask (1) inside to the half-mask (6) inside. <IMAGE> |
