Breathing apparatus

Claim 2

Breathing apparatus comprising a rebreathing system having exhalation valve means through which exhalation to the ambient medium is possible, a variable volume storage container in said system for breathing gas, a fresh-gas supply means for feeding fresh breathing gas from said supply directly into the rebreathing system in response to a predetermined reduction of the volume of the storage container to replace breathing gas that has been consumed and exhausted to the ambient medium, and control means operating independently of time for maintaining the exhalation valve means of the rebreathing system in closed condition with respect to the ambient medium in the course of a series of breaths to and from the rebreathing system and automatically opening the exhalation valve means of the rebreathing system for exhalation to the ambient medium after the termination of said series of breaths, and thereafter automatically closing the exhalation valve to return the rebreathing system to said closed condition.

Claim 3

Breathing apparatus as set forth in claim 1, in which the control means include time-independent means for effecting the opening of the rebreathing system for exhalation to the ambient medium automatically after a predetermined volume of gas has been breathed in the rebreathing system in the course of said series of breaths and maintaining it in the open condition until a predetermined volume of gas has been exhaled to the ambient medium.

Claim 4

Breathing apparatus as set forth in claim 1, in which the control means include time-independent means for effecting the opening of the rebreathing system for exhalation to the ambient medium automatically after a predetermined number of breaths to and from the rebreathing system have been taken in the course of said series of breaths and maintaining it in the open condition until a predetermined number of exhalations to the ambient medium have been made.

Claim 5

Breathing apparatus as set forth in claim 2, in which the control means include means for automatically increasing in dependence of an increase of the ambient pressure the volume of gas breathed in the rebreathing system in the course of said series of breaths.

Claim 6

Breathing apparatus as set forth in claim 4, in which the control means include means for maintaining the rebreathing system in the open condition independently of the ambient pressure until a predetermined volume of gas has been exhaled to the ambient medium.

Claim 7

Breathing apparatus as set forth in claim 3, in which the control means include means for automatically increasing in dependence of an increase of the ambient preSsure the number of breaths of said series of breaths.

Claim 8

Breathing apparatus as set forth in claim 6, in which the control means include means for maintaining the rebreathing system in the open condition independently of the ambient pressure until a predetermined number of exhalations to the ambient medium have been made.

Claim 9

Breathing apparatus as set forth in claim 1, in which the fresh-gas supply include means for feeding fresh gas having a constant content of oxygen to the rebreathing system.

Claim 10

Breathing apparatus as set forth in claim 1, in which the fresh-gas supply includes means for feeding fresh gas having a varying content of oxygen to the rebreathing system.

Claim 11

Breathing apparatus as set forth in claim 9, in which the fresh-gas supply includes means for reducing the oxygen content in dependence of an increase of the ambient pressure.

Claim 12

Breathing apparatus as claimed in claim 1 wherein said rebreathing system comprises a rebreathing circuit, and said exhalation valve means communicates with said circuit.

Claim 13

Breathing apparatus as claimed in claim 11 wherein said exhalation valve means and said control means include means for closing the circuit against circuitous flow of rebreathing gas when the rebreathing system is in open condition with respect to ambient.

Claim 14

Breathing apparatus as claimed in claim 12 wherein said exhalation valve means is located upstream of said means for closing the circuit with respect to the direction of rebreathing flow through the circuit.

Claim 15

Breathing apparatus comprising a rebreathing system having exhalation valve means through which exhalation to the ambient medium is possible, a fresh-gas supply for feeding breathing gas to the rebreathing system to replace breathing gas therein that has been consumed and exhausted to the ambient medium, and control means operating independently of time for maintaining the exhalation valve means of the rebreathing system in closed condition with respect to the ambient medium in the course of a series of breaths to and from the rebreathing system and automatically opening the exhalation valve means of the rebreathing system for exhalation to the ambient medium after the termination of said series of breaths, and thereafter automatically closing the exhalation valve to return the rebreathing system to said closed condition, the exhalation valve means and the control means including two exhalation valves which are biased to closed condition and movable to open condition under the influence of the exhalation pressure, one of these valves being adapted to be opened to open the rebreathing system for exhalation to the ambient medium only while the other one is closed, and integrating means for measuring the volume of gas exhaled to the rebreathing system and including means for blocking said other exhalation valve in its closed condition after a predetermined total volume of gas has been breathed in the rebreathing system in the course of said series of breaths and maintaining it in the closed condition until a predetermined volume of gas has been exhaled to the ambient medium.

Claim 16

Breathing apparatus comprising a rebreathing system having exhalation valve means through which exhalation to the ambient medium is possible, a fresh-gas supply for feeding breathing gas to the rebreathing system to replace breathing gas therein that has been consumed and exhausted to the ambient medium, and control means operating independently of time for maintaining the exhalation valve means of the rebreathing system in closed condition with respect to the ambient medium in the course of a series of breaths to and from the rebreathing system and automatically opening the exhalation valve means of the rebreathing system for exhalation to the ambient medium after the termination of said series of breaths, and thereafter automatically closing the exhalation valve to return the rebreathing system to said closed condition, the exhalation valve means and the control means including two exhalation valves which are biased to closed condition and movable to open condition under the influence of the exhalation pressure, one of these valves being adapted to be opened to open the rebreathing system for exhalation to the ambient medium only while the other one is closed, and integrating means for measuring the volume of gas exhaled to the rebreathing system and including means for blocking said other exhalation valve in its closed condition after a predetermined total volume of gas has been breathed in the rebreathing system in the course of said series of breaths and maintaining it in the closed condition until a predetermined volume of gas has been exhaled to the ambient medium.

Claim 17

Breathing apparatus comprising a rebreathing system having exhalation valve means through which exhalation to the ambient medium is possible, a fresh-gas supply for feeding breathing gas to the rebreathing system to replace breathing gas therein that has been consumed and exhausted to the ambient medium, and control means operating independently of time for maintaining the exhalation valve means of the rebreathing system in closed condition with respect to the ambient medium in the course of a series of breaths to and from the rebreathing system and automatically opening the exhalation valve means of the rebreathing system for exhalation to the ambient medium after the termination of said series of breaths, and thereafter automatically closing the exhalation valve to return the rebreathing system to said closed condition, the exhalation valve means and the control means including two exhalation valves Which are biased to closed condition and movable to open condition under the influence of the exhalation pressure, one of these valves being adapted to be opened to open the rebreathing system for exhalation to the ambient medium only while the other one is closed, and a breath counting mechanism including means for blocking said other exhalation valve in its closed condition after a predetermined number of breaths have been taken in the course of said series of breaths and maintaining it in the closed condition until a predetermined number of exhalations to the ambient medium have been made.

Claim 18

Breathing apparatus comprising a rebreathing system having exhalation valve means through which exhalation to the ambient medium is possible, a fresh-gas supply for feeding breathing gas to the rebreathing system to replace breathing gas therein that has been consumed and exhausted to the ambient medium, and control means operating independently of time for maintaining the exhalation valve means of the rebreathing system in closed condition with respect to the ambient medium in the course of a series of breaths to and from the rebreathing system and automatically opening the exhalation valve means of the rebreathing system for exhalation to the ambient medium after the termination of said series of breaths, and thereafter automatically closing the exhalation valve to return the rebreathing system to said closed condition, the exhalation valve means and the control means including two exhalation valves Which are biased to closed condition and movable to open condition under the influence of the exhalation pressure, one of these valves being adapted to be opened to open the rebreathing system for exhalation to the ambient medium only while the other one is closed, and a breath counting mechanism including means for blocking said other exhalation valve in its closed condition after a predetermined number of breaths have been taken in the course of said series of breaths and maintaining it in the closed condition until a predetermined number of exhalations to the ambient medium have been made.