Divers breathing appts. with oxygen bottle - has diaphragm subjected to environmental pressure controlling oxygen concentration

摘要

The diver's respiratory appts. comprises a mask with inlet and outlet passages contq. non-return valves and leading to a respiratory sac varying in vol. in synchronism with respiration and to bottles of compressed oxygen and inert gas. Each bottle has a diaphragm-type redn. valve calibrated by a spring and supplies the sac, which has venting and inlet devices operating with its variations in volume. The redn. valve of one bottle at least (19) works with an additional corrective diaphragm (41) exposed to the environmental pressure. This automatically alters the calibration of the valve spring (25) and reduces the concentration of oxygen admitted to the sac (17) as this pressure increases.