Surgery – Respiratory method or device – Means for supplying respiratory gas under positive pressure
Patent
1997-10-07
1998-11-24
Weiss, John G.
Surgery
Respiratory method or device
Means for supplying respiratory gas under positive pressure
12820517, 12820524, 12820426, A62B 710
Patent
active
058394354
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a mouthpiece unit adapted for use with a semi closed-circuit breathing apparatus constituted so that exhaled air recovered from a mouthpiece is regenerated by being passed through a carbon dioxide adsorption apparatus, and a mixture of the regenerated gas and a constant flow of fresh gas for inhalation supplied from a breathing gas cylinder is supplied to the mouthpiece as inhalation gas and surplus gas is discharged to the outside.
BACKGROUND ART
Underwater breathing apparatuses can be broadly divided into two types, one type being an open-circuit breathing apparatus and the other type a closed-circuit or semiclosed-circuit breathing apparatus. In an open-circuit breathing apparatus, gas that has been breathed once is expelled from the apparatus, but a closed-circuit or semiclosed-circuit breathing apparatus includes an apparatus that enables gas that has been breathed to be used again.
A closed-circuit or semiclosed-circuit breathing apparatus generally has the advantage of being lighter than an open-circuit breathing apparatus and permitting longer dives to deeper depths. However, since conventional closed-circuit or semiclosed-circuit breathing apparatuses were developed for specialized diving applications or military use, they were equipped with only a minimum of safety mechanisms, and had no mechanisms for coping with emergency situations that occur relatively easily. For this reason, rigorous training was required to use this type of apparatus, and thus it could not be readily used by recreational divers.
However, the growing popularity of diving generated increasing demand for closed-circuit or semiclosed-circuit breathing apparatuses that were not overly complicated to operate and did not require such rigorous training. Equipped as it is with oxygen concentration sensors and the like, a closed-circuit breathing apparatus requires considerable training with respect to handling, control and monitoring. In contrast, a semiclosed-circuit breathing apparatus has no such equipment and therefore can be operated without training, so it can be handled relatively easily even by a non-expert.
Semiclosed-circuit breathing apparatuses that are simpler and easier to use than before would be highly convenient. There are various improvements that can be implemented to make such semiclosed-circuit breathing apparatuses more readily accessible than before. For example, since the pressure in the mouthpiece and in inhalation and exhalation passages in communication with the mouthpiece is about the same as the surrounding pressure, outside water can enter the apparatus via the mouthpiece. If a person using the apparatus is a novice, there is quite a high possibility that while submerged the mouthpiece may become dislodged from the person's mouth, allowing water to enter the apparatus through the mouthpiece. This water can have an adverse effect, such as on the carbon dioxide gas adsorption apparatus. Thus, a mechanism that does not allow the intrusion of water into the apparatus is desirable, and there is a need for a mechanism that will automatically expel any water that does enter.
In the case of an inhalation passage, this type of problem can be resolved by the provision of a check valve at the connection between the inhalation air hose and mouthpiece that only permits a fluid to pass from the inhalation air hose to the mouthpiece. However, a check valve does not solve the problem in the case of an exhalation passage, since exhaled air has to be passed from the mouthpiece to the exhalation air hose, so a different contrivance is required.
In contrast, because an open-circuit breathing apparatus does not have an exhalation air hose and the pressure inside the inhalation air hose is higher than the surrounding pressure, the entry of outside water into the apparatus via the mouthpiece does not occur.
Concerning this point, in International Patent Application No. W/O 95/09762 the present inventors proposed a mouthpiece unit that is easy to use, even by a novice. This mouthp
REFERENCES:
patent: 4273120 (1981-06-01), Oswell
patent: 4781184 (1988-11-01), Fife
patent: 4938211 (1990-07-01), Takahashi et al.
Hashimoto Kiyoshi
Matsuoka Shunsuke
Anderson Charles W.
Grand Bleu Inc.
Weiss John G.
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