Diving vest

Claim 1

In an underwater breathing apparatus in which the volume of gas supplied in a given period is small compared with the total volume inhaled and exhaled by the diver during the same period, the improvement comprising: A helmet connected through a first check valve for flow of breathing mixture to the inlet connection; Quality-maintaining means to maintain the breathable quality of breathing mixture in the helmet and to maintain a pressure of breathing mixture therein approximately equal to the pressure of external ambient water, having separate inlet and outlet connections, having connected between the said inlet and outlet connections carbon dioxide absorbing means in series with oxygen replenishment means automatically controlled to maintain a predetermined partial pressure of oxygen in the breathing mixture; and having a source of inert diluent gas controlled to maintain a predetermined total pressure of breathing mixture; An oral-nasal cavity within the helmet, connected through a second check valve to the outlet connection of the quality maintaining means to permit flow of breathing mixture from the outlet connection to the oral-nasal cavity; and connected through a third check valve to the space within the helmet to permit flow of exhaled breathing mixture from the oral-nasal cavity to the space within the helmet; A double-walled flexible inner garment adapted to surround the diver''s body from the helmet to his waist, its outer wall being sealed to the edge of the helmet, its interior being connected to the interior of the helmet; A nonstretching outer garment adapted to surround the doublewalled flexible inner garment, fitting the inner garment sufficiently closely so that inflation of the latter can cause the inner garment to press against the interior of the outer garment and form a seal between the outer garment and the body of the diver.