| 摘要 |
A respirator contains the half-mask made of air-impermeable material with two symmetrically attached filtering cartridges, the breath-out valve with the protective collar located axially in the lower part of the half-mask, and the head-enclosing part. To reduce the resistance to the breath-out, the second breath-out valve in the centre of the half-mask between the filtering cartridges is provided. |
