Rechargeable breathing apparatus particularly an apparatus for divers

#The present invention relates to a rechargeable breathing apparatus with a closed breathing system, in particular for aqua divers and smoke divers, comprising a breathing bellows for receiving the exhaled air, which is connected, by means of a hydrostatic valve, to a pressurized gas container, and which bellows is arranged to deliver breathing air to the diver subsequent to removal of CO2 and addition of O2.

#Breathing devices for diving in water may be divided into three main groups, open, closed, and semi-closed systems. In open systems, the inhalation is made from a pressurized bottle, and the exhalation is made directly to the surrounding water. The drawbacks are that unconsumed oxygen gas is breathed directly into the water. During deep-sea diving the air source has to be replaced during the descent and ascent, in order for the diver not to suffer from poisoning or lack of oxygen. The system is relatively noisy; it has a high acoustic profile, and emits air bubbles. Further, it demands a surface organization, with access to a compressor or pressurized bottles. The advantage is the relative simplicity of the system.

#Closed and semi-closed systems involve purification of the exhaled air from carbon dioxide in a container with, for example, calcium hydroxide. The purified gas then continues to a breathing sack, where new oxygen gas is added from a pressurized bottle. It is also possible to add new inert gas from an inert gas-bottle, in order to compensate for any increase in depth. The drawbacks are the complexity and vulnerability of the system for dosage and monitoring, the toxicity of the calcium hydroxide, and the fact that it is a consumable substance that has to be replaced after each dive. Pressurized oxygen entails risk of fire or explosion. This system too, demands an extensive surface organization, with ability to supply calcium hydroxide, pressurized oxygen, and inert gas. The advantages of a closed system is that the system does not generate any bubbles and has a low noise level, and that there is no need for gas replacement when descending and ascending during deep-sea diving. The advantages with a semi-closed system are that it produces less bubbles than an open system, and that it has a low noise level. The disadvantage is the difficulty to control the oxygen partial pressure, and the large surface organization needed in order to provide mixed gas and calcium hydroxide.

#In the following detailed description, the present invention will be described more closely in an embodiment, with reference to the attached drawing, which is a side, elevational, schematic representation of a breathing apparatus in accordance with the present invention.

#The breathing apparatus according to the present invention comprises of a housing 10, in which is arranged an oxygen accumulator 12 in the shape of a container 13, sealed at is upper end, with openings 14 in the bottom of the container, and a heating and/or cooling element arranged in the accumulator. The envelope surface 16 of the container is surrounded, with the exception of its perforated bottom side, by a chamber 18, which is connected, on the one hand to an inlet 20 for incoming exhaled air, and on the other hand to an outlet 22 leading to a carbon dioxide absorber 24, which in turn communicates with a breathing bellows 28, equipped with an outlet 30 for inhalation air.

#The container 13 of the oxygen accumulator 12 contains a reversibly oxygen-fixating agent, which may be comprised, e.g., by a metal complex such as, e.g., cobalt-bis-salicylaldehyde-ethylene-diimine (Salcomine), cobalt-bis-3-fluoro-salicylaldehyde-ethylene-diimine (Fluomine), or cobalt-bis-3-ethoxy-salicylaldehyde-ethylene-diimine. Metal complexes in the form of cobalt phorfyrins may also be used. The use of simple inorganic salts is also contemplated. Said agents possess the feature of fixating oxygen within a certain, lower, temperature interval, and re-releasing the oxygen within a certain, higher, temperature interval. The ambient partial pressure of oxygen also constitutes an important factor thereby, since desorbtion decreases with an increasing pressure. When exhaled gas enters the chamber 18 surrounding the oxygen accumulator 12, the latter is warmed by the exhaled air, and if this heat is not sufficient, heat is supplied by the heating element 11 (which can be a heating or cooling element in different embodiments of the present invention), so that the oxygen liberated in the container of the accumulator 13 migrates downwards through a particle filter 32, where any chemical dust is separated. The oxygen continues through a further vapor filter 34, consisting e.g. of a silicon gel or a zeolite, preventing water vapor from entering the accumulator.

#The outlet of the steam filter 34 communicates with the breathing bellows 28, in which also terminates a conduit 36 from a pressurized bottle 38, which contains a gas. This gas may be helium or some other gas mixture for diving deeper than 60 meters, or air for shallower diving. The function of the bellows is to act as gas storage between exhalation and inhalation. The inert gas supply may be constituted by two exchangeable five liter-bottles, a helium bottle, or air or some other diveable gas, while the other bottle with compressed air is arranged with a connection nipple 40, so that it may be easily connected to a manually operable hand or foot pump or the like. In the conduit 36 between the pressurized bottle 38 and the breathing bellows 28 there is arranged a hydrostatic valve 42, and in the breathing bellows there is arranged a pressure relief valve 44.