Respirators

Claim 2

In a respirator for supplying breathable gas to a user and having an insufflation phase and an exhalation phase, in combination: a user circuit including user connection means, an insufflation line having one end connected to said user connection means and an exhalation line having one end connected to said user connection means; supply means for introducing breathable gas under pressure to the opposite end of said insufflation line;

Claim 3

an insufflation valve in the insufflation line; an exhalation valve having an inlet connected to the opposite end of said exhalation line and an outlet communicating with the atmosphere; control means connected to the insufflation valve and the exhalation valve for opening and closing said valves at predetermined times, the opening of the insufflation valve initiating the insufflation phase and the opening of the exhalation valve initiating the exhalation phase; a reservoir forming a storage container for breathable gas from the supply means, means for maintaining the gas in the reservoir at a predetermined pressure greater than the pressure within the insufflation line at the beginning of the insufflation phase; conduit means including a pair of branch conduits connected in parallel relationship between the storage container and the insufflation line upstream of the insufflation valve, unidirectional flow means in one of said branch conduits for supplying breathable gas from said storage container to the user circuit during the insufflation phase; and unidirectional flow means in said other branch conduit responsive to the maximum insufflation pressure in said insufflation line for supplying breathable gas to said reservoir when said maximum insufflation pressure is reached, whereby the pressure in said container is maintained lower than that in said circuit during the final portion of the insufflation phase and the initial portion of the exhalation phase.

Claim 4

an insufflation valve in the insufflation line; an exhalation valve having an inlet connected to the opposite end of said exhalation line and an outlet communicating with the atmosphere; control means connected to the insufflation valve and the exhalation valve for opening and closing said valves at predetermined times, the opening of the insufflation valve initiating the insufflation phase and the opening of the exhalation valve initiating the exhalation phase; a reservoir forming a storage container for breathable gas from the supply means, means for maintaining the gas in the reservoir at a predetermined pressure greater than the pressure within the insufflation line at the beginning of the insufflation phase; conduit means including a pair of branch conduits connected in parallel relationship between the storage container and the insufflation line upstream of the insufflation valve, unidirectional flow means in one of said branch conduits for supplying breathable gas from said storage container to the user circuit during the insufflation phase; and unidirectional flow means in said other branch conduit responsive to the maximum insufflation pressure in said insufflation line for supplying breathable gas to said reservoir when said maximum insufflation pressure is reached, whereby the pressure in said container is maintained lower than that in said circuit during the final portion of the insufflation phase and the initial portion of the exhalation phase.

Claim 5

In a respirator for supplying breathable gas to a user and having an insufflation phase and an exhalation phase, in combination: a user circuit including user connection means, an insufflation line having one end connected to said user connection means, and an exhalation line having one end connected to said user connection means; supply means for introducing breathable gas under pressure to the opposite end of said insufflation line; an insufflation valve in the insufflation line; an exhalation valve having an inlet connected to the opposite end of said exhalation line and an outlet communicating with the atmosphere; control means connected to the insufflation valve and the exhalation valve for opening and closing said valves, the opening of the insufflation valve initiating the insufflation phase and the opening of the exhalation valve initiating the exhalation phase, said control means closing the insufflation valve prior to the opening of the exhalation valve during each breathing cycle; a reservoir forming a storage container for breathable gas from the supply means, means for maintaining the gas in the reservoir at a predetermined pressure greater than the pressure within the insufflation line at the beginning of the insufflation phase; conduit means interconnecting the storage container and the insufflation line upstream of the insufflation valve for supplying unidirectional flow of the breathable gas from said storage container to the user circuit during the insufflation phase; and unidirectional flow means connected in the conduit means and responsive to the maximum insufflation pressure in said insufflation line for supplying breathable gas to said reservoir when said maximum insufflation pressure is reached, whereby the pressure in said container is maintained lower than that in said circuit during the final portion of the insufflation phase and the initial portion of the exhalation phase.

Claim 6

In a respirator for supplying breathable gas to a user and having an insufflation phase and an exhalation phase, in combination: a user circuit including user connection means, an insufflation line having one end connected to said user connection means, and an exhalation line having one end connected to said user connection means; supply means for introducing breathable gas under pressure to the opposite end of said insufflation line; an insufflation valve in the insufflation line; an exhalation valve having an inlet connected to the opposite end of said exhalation line and an outlet communicating with the atmosphere; control means connected to the insufflation valve and the exhalation valve for opening and closing said valves, the opening of the insufflation valve initiating the insufflation phase and the opening of the exhalation valve initiating the exhalation phase, said control means closing the insufflation valve prior to the opening of the exhalation valve during each breathing cycle; a reservoir forming a storage container for breathable gas from the supply means, means for maintaining the gas in the reservoir at a predetermined pressure greater than the pressure within the insufflation line at the beginning of the insufflation phase; conduit means interconnecting the storage container and the insufflation line upstream of the insufflation valve for supplying unidirectional flow of the breathable gas from said storage container to the user circuit during the insufflation phase; and unidirectional flow means connected in the conduit means and responsive to the maximum insufflation pressure in said insufflation line for supplying breathable gas to said reservoir when said maximum insufflation pressure is reached, whereby the pressure in said container is maintained lower than that in said circuit during the final portion of the insufflation phase and the initial portion of the exhalation phase.

Claim 7

In a respirator for supplying breathable gas to a user and having an insufflation phase and an exhalation phase, in combination: a user circuit including user connection means, an insufflation line having one end connected to said user connection means and an exhalation line having one end connected to said user connection means; supply means for introducing breathable gas under pressure to the opposite end of said insufflation line; an insufflation valve in the insufflation line; an exhalation valve having an inlet connected to the opposite end of said exhalation line and an outlet communicating with the atmosphere; control means connected to the insufflation valve and the exhalation valve for opening and closing said valves at predetermined times, the opening of the insufflation valve initiating the insufflation phase and the opening of the exhalation valve initiating the exhalation phase; a reservoir forming a storage container for breathable gas from the supply means means for maintaining the gas in the reservoir at a predetermined pressure greater than the pressure within the insufflation phase; and conduit means including a pair of branch conduits connected in parallel relationship between the storage container and the insufflation line upstream of the insufflation valve for supplying breathable gas from said storage container to the user circuit during the insufflation phase and for maintaining the pressure in said container lower than that in said circuit during the final portion of the insufflation phase and the initial portion of the exhalation phase, one of said branch conduits having a regulator valve for admitting breathable gas to the storage container when the pressure in said circuit is at least equal to the maximum insufflation pressure, and the other of said branch conduits having a nonreturn valve for preventing the flow of breathable gas from the insufflation line to the storage container.

Claim 8

In a respirator for supplying breathable gas to a user and having an insufflation phase and an exhalation phase, in combination: a user circuit including user connection means, an insufflation line having one end connected to said user connection means and an exhalation line having one end connected to said user connection means; supply means for introducing breathable gas under pressure to the opposite end of said insufflation line; an insufflation valve in the insufflation line; an exhalation valve having an inlet connected to the opposite end of said exhalation line and an outlet communicating with the atmosphere; control means connected to the insufflation valve and the exhalation valve for opening and closing said valves at predetermined times, the opening of the insufflation valve initiating the insufflation phase and the opening of the exhalation valve initiating the exhalation phase; a reservoir forming a storage container for breathable gas from the supply means means for maintaining the gas in the reservoir at a predetermined pressure greater than the pressure within the insufflation phase; and conduit means including a pair of branch conduits connected in parallel relationship between the storage container and the insufflation line upstream of the insufflation valve for supplying breathable gas from said storage container to the user circuit during the insufflation phase and for maintaining the pressure in said container lower than that in said circuit during the final portion of the insufflation phase and the initial portion of the exhalation phase, one of said branch conduits having a regulator valve for admitting breathable gas to the storage container when the pressure in said circuit is at least equal to the maximum insufflation pressure, and the other of said branch conduits having a nonreturn valve for preventing the flow of breathable gas from the insufflation line to the storage container.

Claim 9

In a respirator for supplying breathable gas to a user and having an insufflation phase and an exhalation phase, in combination: a user circuit including user connection means, an insufflation line having one end connected to said user connection means and an exhalation line having one end connected to said user connection means; supply means for introducing breathable gas under pressure to the opposite end of said insufflation line; an insufflation valve in the insufflation line; an exhalation valve having an inlet connected to the opposite end of said exhalation line and an outlet communicating with the atmosphere; control means connected to the insufflation valve and the exhalation valve for opening and closing said valves at predetermined times, the opening of the insufflation valve initiating the insufflation phase and the opening of the exhalation valve initiating the exhalation phase; a reservoir forming a storage container for breathable gas from the supply means, means for maintaining the gas in the reservoir at a pressure greater than the pressure within the insufflation line at the beginning of the insufflation phase; and conduit means including a pair of branch conduits connected in parallel relationship between the storage container and the insufflation line upstream of the insufflation valve for supplying breathable gas from said storage container to the user circuit during the insufflation phase and for maintaining the pressure in said container lower than that in said circuit during the final portion of the insufflation phase and the initial portion of the exhalation phase, one of said branch conduits having a regulator valve for admitting breathable gas to the storage container when the pressure in said circuit is at least equal to the maximum insufflation pressure, and the other of said branch conduits having a nonreturn valve for preventing the flow of breathable gas from the insufflation line to the storage container.

Claim 10

In a respirator for supplying breathable gas to a user and having an insufflation phase and an exhalation phase, in combination: a user circuit including user connection means, an insufflation line having one end connected to said user connection means and an exhalation line having one end connected to said user connection means; supply means for introducing breathable gas under pressure to the opposite end of said insufflation line; an insufflation valve in the insufflation line; an exhalation valve having an inlet connected to the opposite end of said exhalation line and an outlet communicating with the atmosphere; control means connected to the insufflation valve and the exhalation valve for opening and closing said valves at predetermined times, the opening of the insufflation valve initiating the insufflation phase and the opening of the exhalation valve initiating the exhalation phase; a reservoir forming a storage container for breathable gas from the supply means, means for maintaining the gas in the reservoir at a pressure greater than the pressure within the insufflation line at the beginning of the insufflation phase; and conduit means including a pair of branch conduits connected in parallel relationship between the storage container and the insufflation line upstream of the insufflation valve for supplying breathable gas from said storage container to the user circuit during the insufflation phase and for maintaining the pressure in said container lower than that in said circuit during the final portion of the insufflation phase and the initial portion of the exhalation phase, one of said branch conduits having a regulator valve for admitting breathable gas to the storage container when the pressure in said circuit is at least equal to the maximum insufflation pressure, and the other of said branch conduits having a nonreturn valve for preventing the flow of breathable gas from the insufflation line to the storage container.

Claim 11

In a respirator as defined in claim 4, said storage container comprising a compressible bellows; and spring means for exerting a continuous compressive force on the bellows.

Claim 12

In a respirator as defined in claim 4, in which said storage container comprises a bladder of elastic material.

Claim 13

In a respirator for supplying breathable gas to a user and having an insufflation phase and an exhalation phase, in combination: a user circuit including connection means, an insufflation line and an exhalation line connected to said user connection means; venturi means having a discharge portion communicating with the insufflation line and an injector portion; supply means for introducing breathable gas under pressure to the injector portion of the venturi means; an insufflation valve in the insufflation line; an exhalation valve in the exhalation line; control means connected to the insufflation valve and the exhalation valve for opening and closing said valves at predetermined times, the opening of the insufflation valve initiating the insufflation phase and the opening of the exhalation valve initiating the exhalation phase; a reservoir forming a storage container for breathable gas from the supply means, means for maintaining the gas in the reservoir at a predetermined pressure greater than the pressure within the insufflation line at the beginning of the insufflation phase; conduit means interconnecting the storage container and the venturi means upstream of the insufflation valve for supplying unidirectional flow of breathable gas from said storage container to the user circuit during the insufflation phase; and unidirectional flow means connected to the conduit means and responsive to the maximum insufflation pressure in said insufflation line for supplying breathable gas to said reservoir when said maximum insufflation pressure is reached, whereby the pressure in said container is maintained lower than that in said circuit during the final portion of the insufflation phase and the initial portion of the exhalation phase.

Claim 14

In a respirator for supplying breathable gas to a user and having an insufflation phase and an exhalation phase, in combination: a user circuit including connection means, an insufflation line and an exhalation line connected to said user connection means; venturi means having a discharge portion communicating with the insufflation line and an injector portion; supply means for introducing breathable gas under pressure to the injector portion of the venturi means; an insufflation valve in the insufflation line; an exhalation valve in the exhalation line; control means connected to the insufflation valve and the exhalation valve for opening and closing said valves at predetermined times, the opening of the insufflation valve initiating the insufflation phase and the opening of the exhalation valve initiating the exhalation phase; a reservoir forming a storage container for breathable gas from the supply means, means for maintaining the gas in the reservoir at a predetermined pressure greater than the pressure within the insufflation line at the beginning of the insufflation phase; conduit means interconnecting the storage container and the venturi means upstream of the insufflation valve for supplying unidirectional flow of breathable gas from said storage container to the user circuit during the insufflation phase; and unidirectional flow means connected to the conduit means and responsive to the maximum insufflation pressure in said insufflation line for supplying breathable gas to said reservoir when said maximum insufflation pressure is reached, whereby the pressure in said container is maintained lower than that in said circuit during the final portion of the insufflation phase and the initial portion of the exhalation phase.

Claim 15

In a respirator for supplying breathable gas to a user and having an insufflation phase and an exhalation phase, in combination: a user circuit including user connection means, an insufflation line and an exhalation line connected to said user connection means; venturi means having a discharge portion communicating with the insufflation line and an injector portion; supply means for introducing breathable gas under pressure to the injector portion of the venturi means; an insufflation valve in the insufflation line; an exhalation valve in the exhalation line; control means connected to the insufflation valve and the exhalation valve for opening and closing said valves, the opening of the insufflation valve initiating the insufflation phase and the opening of the exhalation valve initiating the exhalation phase; a reservoir forming a storage container for breathable gas from the supply means for maintaining the gas in the reservoir at a predetermined pressure greater than the pressure within the insufflation line at the beginning of the insufflation phase; and conduit means including a pair of branch conduits connected in parallel relationship between the storage container and the venturi means upstream of the insufflation valve for supplying breathable gas from said storage container to the user circuit and for maintaining the pressure in said container lower than that in said circuit during the final portion of the insufflation phase and the initial portion of the exhalation phase, one of said branch conduits having a regulator valve for admitting breathable gas to the storage container when the pressure in said circuit is at least equal to the maximum insufflation pressure, and the other of said branch conduits having a nonreturn valve for preventing the flow of breathable gas from the venturi means to the storage container.

Claim 16

In a respirator for supplying breathable gas to a user and having an insufflation phase and an exhalation phase, in combination: a user circuit including user connection means, an insufflation line and an exhalation line connected to said user connection means; venturi means having a discharge portion communicating with the insufflation line and an injector portion; supply means for introducing breathable gas under pressure to the injector portion of the venturi means; an insufflation valve in the insufflation line; an exhalation valve in the exhalation line; control means connected to the insufflation valve and the exhalation valve for opening and closing said valves, the opening of the insufflation valve initiating the insufflation phase and the opening of the exhalation valve initiating the exhalation phase; a reservoir forming a storage container for breathable gas from the supply means for maintaining the gas in the reservoir at a predetermined pressure greater than the pressure within the insufflation line at the beginning of the insufflation phase; and conduit means including a pair of branch conduits connected in parallel relationship between the storage container and the venturi means upstream of the insufflation valve for supplying breathable gas from said storage container to the user circuit and for maintaining the pressure in said container lower than that in said circuit during the final portion of the insufflation phase and the initial portion of the exhalation phase, one of said branch conduits having a regulator valve for admitting breathable gas to the storage container when the pressure in said circuit is at least equal to the maximum insufflation pressure, and the other of said branch conduits having a nonreturn valve for preventing the flow of breathable gas from the venturi means to the storage container.

Claim 17

In a respirator as defined in claim 8, the venturi means including a divergent section connected to said one branch conduit and a convergent section connected to said other branch conduit.

Claim 18

In a respirator as defined in claim 8, the venturi means including a divergent section communicating with said insufflation line and a convergent section communicating with each of said branch conduits.

Claim 19

In a respirator for supplying breathable gas to a user and having an insufflation phase and an exhalation phase, in combination: a user circuit including user connection means, an insufflation line and an exhalation line connected to said user connection means; venturi means having a convergent portion, a divergent portion communicating with the insufflation line, and an injector portion; means including a compressed gas generator for introducing breathable gas under pressure to the injector portion of the venturi means; an insufflation valve in the insufflation line; an exhalation valve in the exhalation line; control means connected to the insufflation valve and the exhalation valve for opening and closing said valves at predetermined times, the opening of the insufflation valve initiating the insufflation phase and the opening of the exhalation valve initiating the exhalation phase; a reservoir forming a storage container for breathable gas from the generator, means for maintaining the gas in the reservoir at a predetermined pressure greater than the pressure within the insufflation line at the beginning of the insufflation phase; and conduit means including a pair of branch conduits connected in parallel relationship between the storage container and the convergent portion and divergent portion of the venturi means, respectively, and upstream of the insufflation valve for supplying breathable gas from said storage container to the user circuit and for maintaining the pressure in said container lower than that in said circuit during the final portion of the insufflation phase and the initial portion of the exhalation phase, one of said branch conduits connected between the convergent portion and said storage container having unidirectional flow means for preventing the flow of breathable gas from said convergent portion to the storage container, the other of said branch conduits connected between the divergent portion and the storage container including unidirectional flow means responsive to the maximum insufflation pressure in said insufflation line for supplying breathable gas to said reservoir when said maximum insufflation pressure is reached.

Claim 20

In a respirator for supplying breathable gas to a user and having an insufflation phase and an exhalation phase, in combination: a user circuit including user connection means, an insufflation line and an exhalation line connected to said user connection means; venturi means having a convergent portion, a divergent portion communicating with the insufflation line, and an injector portion; means including a compressed gas generator for introducing breathable gas under pressure to the injector portion of the venturi means; an insufflation valve in the insufflation line; an exhalation valve in the exhalation line; control means connected to the insufflation valve and the exhalation valve for opening and closing said valves at predetermined times, the opening of the insufflation valve initiating the insufflation phase and the opening of the exhalation valve initiating the exhalation phase; a reservoir forming a storage container for breathable gas from the generator, means for maintaining the gas in the reservoir at a predetermined pressure greater than the pressure within the insufflation line at the beginning of the insufflation phase; and conduit means including a pair of branch conduits connected in parallel relationship between the storage container and the convergent portion and divergent portion of the venturi means, respectively, and upstream of the insufflation valve for supplying breathable gas from said storage container to the user circuit and for maintaining the pressure in said container lower than that in said circuit during the final portion of the insufflation phase and the initial portion of the exhalation phase, one of said branch conduits connected between the convergent portion and said storage container having unidirectional flow means for preventing the flow of breathable gas from said convergent portion to the storage container, the other of said branch conduits connected between the divergent portion and the storage container including unidirectional flow means responsive to the maximum insufflation pressure in said insufflation line for supplying breathable gas to said reservoir when said maximum insufflation pressure is reached.

Claim 21

In a respirator as defined in claim 11, which further comprises, in combination: nebulizer means connected to the insufflation line; and means including a supply conduit for introducing breathable gas from said generator to said nebulizer means simultaneously with the opening of said insufflation valve.

Claim 22

In a respirator for supplying breathable gas to a user and having an insufflation phase and an exhalation phase, in combination: a user circuit including user connection means, an insufflation line and an exhalation line connected to said user connection means; venturi means having a convergent portion, a divergent portion communicating with the insufflation line, and an injector portion; means including a compressed gas generator for introducing breathable gas under pressure to the injector portion of the venturi means; an insufflation valve in the insufflation line; an exhalation valve in the exhalation line; control means connected to the insufflation valve and an exhalation valve for opening and closing said valves, the opening of the insufflation valve initiating the insufflation phase and the opening of the exhalation valve initiating the exhalation phase, said control means closing the insufflation valve prior to the opening of the exhalation valve during each breathing cycle; a reservoir forming a storage container for breathable gas from the generator, means for maintaining the gas in the reservoir at a predetermined pressure greater than the pressure within the insufflation line at the beginning of the insufflation phase; and conduit means including a plurality of branch conduits interconnecting the storage container and the venturi means upstream of the insufflation valve for supplying breathable gas from said storage container to the user circuit during the insufflation phase; and means connected to the conduit means for maintaining the pressure in said container lower than that in said circuit during the final portion of the insufflation phase and the initial portion of the exhalation phase, one of said branch conduits having a regulator valve for admitting breathable gas to the storage container during the exhalation phase and when the pressure in said circuit is at least equal to the maximum insufflation pressure during the insufflation phase, and the other of said branch conduits communicating with the convergent portion of the venturi means and having a nonreturn valve for preventing the flow of breathable gas from said convergent portion to the storage container.

Claim 23

In a respirator for supplying breathable gas to a user and having an insufflation phase and an exhalation phase, in combination: a user circuit including user connection means, an insufflation line and an exhalation line connected to said user connection means; venturi means having a convergent portion, a divergent portion communicating with the insufflation line, and an injector portion; means including a compressed gas generator for introducing breathable gas under pressure to the injector portion of the venturi means; an insufflation valve in the insufflation line; an exhalation valve in the exhalation line; control means connected to the insufflation valve and an exhalation valve for opening and closing said valves, the opening of the insufflation valve initiating the insufflation phase and the opening of the exhalation valve initiating the exhalation phase, said control means closing the insufflation valve prior to the opening of the exhalation valve during each breathing cycle; a reservoir forming a storage container for breathable gas from the generator, means for maintaining the gas in the reservoir at a predetermined pressure greater than the pressure within the insufflation line at the beginning of the insufflation phase; and conduit means including a plurality of branch conduits interconnecting the storage container and the venturi means upstream of the insufflation valve for supplying breathable gas from said storage container to the user circuit during the insufflation phase; and means connected to the conduit means for maintaining the pressure in said container lower than that in said circuit during the final portion of the insufflation phase and the initial portion of the exhalation phase, one of said branch conduits having a regulator valve for admitting breathable gas to the storage container during the exhalation phase and when the pressure in said circuit is at least equal to the maximum insufflation pressure during the insufflation phase, and the other of said branch conduits communicating with the convergent portion of the venturi means and having a nonreturn valve for preventing the flow of breathable gas from said convergent portion to the storage container.

Claim 24

In a respirator for supplying breathable gas to a user and having an insufflation phase and an exhalation phase, in combination: a user circuit including user connection means, an insufflation line and an exhalation line connected to said user connection means; venturi means having a convergent portion, a divergent portion communicating with the insufflation line, and an injector portion; a compressed gas generator for introducing breathable gas under pressure to the injector portion of the venturi means; a pneumatically operated insufflation valve in the insufflation line; a pneumatically operated exhalation valve in the exhalation line for connecting the same to the atmosphere; control means connected to the insufflation valve and the exhalation valve for automatically applying pressure thereto from said generator at predetermined times, to open and close said valves, the opening of the insufflation valve initiating the insufflation phase and the opening of the exhalation valve initiating the exhalation phase; a reservoir forming a storage container for breathable gas from the generator; and conduit means including a plurality of branch conduits interconnecting the storage container and the venturi means upstream of the insufflation valve for supplying breathable gas from said storage container to the user circuit and for maintaining the pressure in said container lower than that in said circuit during the final portion of the insufflation phase and the initial portion of the exhalation phase, one of said branch conduits being connected to the divergent portion of the venturi means and having a regulator valve for admitting breathable gas from said divergent portion to the storage container when the pressure in said circuit is at least equal to the maximum insufflation pressure, and the other of said branch conduits being connected to the convergent portion of the venturi means and having a nonreturn valve for preventing the flow of breathable gas from said convergent portion to the storage container.

Claim 25

In a respirator for supplying breathable gas to a user and having an insufflation phase and an exhalation phase, in combination: a user circuit including user connection means, an insufflation line and an exhalation line connected to said user connection means; venturi means having a convergent portion, a divergent portion communicating with the insufflation line, and an injector portion; a compressed gas generator for introducing breathable gas under pressure to the injector portion of the venturi means; a pneumatically operated insufflation valve in the insufflation line; a pneumatically operated exhalation valve in the exhalation line for connecting the same to the atmosphere; control means connected to the insufflation valve and the exhalation valve for automatically applying pressure thereto from said generator at predetermined times, to open and close said valves, the opening of the insufflation valve initiating the insufflation phase and the opening of the exhalation valve initiating the exhalation phase; a reservoir forming a storage container for breathable gas from the generator; and conduit means including a plurality of branch conduits interconnecting the storage container and the venturi means upstream of the insufflation valve for supplying breathable gas from said storage container to the user circuit and for maintaining the pressure in said container lower than that in said circuit during the final portion of the insufflation phase and the initial portion of the exhalation phase, one of said branch conduits being connected to the divergent portion of the venturi means and having a regulator valve for admitting breathable gas from said divergent portion to the storage container when the pressure in said circuit is at least equal to the maximum insufflation pressure, and the other of said branch conduits being connected to the convergent portion of the venturi means and having a nonreturn valve for preventing the flow of breathable gas from said convergent portion to the storage container.