Portable breathing appts. for shallow water diving - has flexible bag with compartments for atmospheric pressure air and gravel ballast

摘要

The portable breathing apparatus esp. for shallow water diving (down to 15m) comprises a framework of light alloy in which is housed a flexible airtight container (3). A flexible diaphragm (4) divides this into two chambers (1, 2) either of which can expand to fill the whole space. A hose (5) from each of the chambers (1, 2) leads to a mouthpiece assembly (6). This includes non-return valves so that the breathing process transfers air from one chamber to the other, and a reversing arrangement so that the air can be breathed more than once. A second flexible container (13) fixed to the first with straps (16) is for ballast (gravel, sand). The filling hole is at the bottom to allow the ballast to drop out when the cover (15) is removed, permitting rapid surfacing.