| 摘要 |
To enable the weaver of a face mask (19) to breathe a protective gas, a liq. gas container (23) is connected to the mouthpiece (18) without risk of contamination. Projecting from the container is a tubular shell with an externally threaded bush (3) on its end, which is screwed into a nut (2) on the mouthpiece. Also supported by the shell is a hollow needle (37) which is forced through sealing elements to discharge the gas into the mouthpiece. The needle carries a square-threaded nut (35) which rotates inside an internally threaded part (29) of the shell so that the pointed tip of the needle firstly pierces a thin membrane at the front of the bush, then pierces a thicker membrane (5) inside the nut. The gas is then discharged through holes (38) at the tip of the needle. ADVANTAGE - The wearer of the mask can breathe safely for long periods of time.
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