| 摘要 |
Breathing apparatus is provided for use under water, in a noxious atmosphere or under like conditions, which provides pressure compensation during release of the consumed breathing gas. The apparatus includes a connection device such as a breathing mask for connecting the apparatus to the breathing organs of a user and a breathing circuit which communicates with the connection device and includes a carbon-dioxide absorber and an expansible gas chamber. The apparatus includes controls which, during the operation of the breathing circuit, provide (i) a first operating period wherein the breathing circuit is closed and a breathing gas is caused to circulate in the breathing circuit until the oxygen concentration of the circulating breathing gas is reduced to a predetermined value and (ii) a second operating period which alternates with the first period, wherein the used breathing gas is released to the ambient environment and fresh gas is supplied to the breathing circuit. A dosing container is connected to the breathing circuit which, during the first operating period, receives fresh gas therein having a predetermined pressure exceeding the pressure of the breathing circuit. During the second operation period, the dosing container supplies the contents thereof to the breathing circuit, at the same time as the volume of the expansible gas chamber is increased, until the pressure in the dosing container is substantially equal to the pressure in the breathing circuit.
|
