Pressure reducing system for a breathing apparatus

1 . A pressure reducing system for a breathing apparatus comprising:

a conduit for supplying a breathable gas under pressure;

a mouthpiece for inspiration of the breathable gas by a user;

a valve poppet operatively interposed between the conduit and the mouthpiece,

the valve poppet being movable between:

a closed position, in which the valve poppet prevents passing of the breathable gas from the conduit to the mouthpiece, and

at least one open position in which the valve poppet permits the passing of the breathable gas from the conduit to the mouthpiece,

said conduit comprising an abutment against which the valve poppet abuts in the closed position and from which the valve poppet is distanced in said at least one open position, and

said abutment defining an annular interface which in the closed position is in contact with the valve poppet in order to perform a fluid-dynamic sealing action that prevents the passing of the breathable gas from the conduit to the mouthpiece, the annular interface being located on an end surface of the abutment; and

a balancing chamber that defines a pressure balancing zone, the balancing chamber during operation enabling at least a partial balancing of the force exerted by the pressure of the breathable gas on the valve poppet at the abutment, said valve poppet being at least in part interposed between the abutment and the balancing chamber; the valve poppet defining a passage that places the conduit and the balancing chamber in fluid communication even in the closed position of the valve poppet, wherein a section of said passage, in at least one of said open positions extends in the conduit beyond said annular interface; and wherein said passage extends in the conduit beyond said annular interface in all of said open positions of the valve poppet.

2 . The pressure reducing system according to claim 1 , further comprising an actuator for shifting the valve poppet along a travel path having as opposite travel limits:

the closed position; and

a position of distancing reached without modifying the positioning of the balancing chamber,

said passage extending in the conduit beyond the annular interface in any position of said travel path.

3 . The pressure reducing system according to claim 1 , further comprising a system for moving the balancing chamber towards said abutment in order to move the valve poppet from said at least one open position to the closed position upon the occurrence of at least one particular operating condition wherein no mechanical spring is present between the valve poppet and the balancing chamber.

4 . The pressure reducing system according to claim 1 , wherein said annular interface lies in an imaginary plane orthogonal to a shifting direction of the valve poppet.

5 . The pressure reducing system according to claim 1 , wherein

said valve poppet comprises a main portion, and

said passage comprises:

an inner tubular portion obtained in said main portion; and

a tubular extension outside the main portion.

6 . The pressure reducing system according to claim 5 , wherein said tubular extension is in one body with said inner tubular portion.

7 . The pressure reducing system according to claim 5 , wherein the tubular portion and the tubular extension have the same passage section or they differ by less than 25%.

8 . The pressure reducing system according to claim 1 , wherein in a zone intended to come into contact with the abutment, the valve poppet comprises a sealing element; the abutment having a profile to optimise the seal with the pad.

9 . The pressure reducing system according to claim 1 , wherein:

inside the balancing chamber the valve poppet has a pushing surface for closing that is larger than the surface of the valve poppet which in the closed position faces the section for the passage of gas at the abutment; or

an elastic spring is present between the valve poppet and the balancing chamber.

10 . A breathing system comprising:

a tank of a breathable gas;

a first pressure reduction stage situated downstream of the tank;

a second pressure reduction stage situated downstream of the first stage and comprising a pressure reducing system; and

a tube connecting the first stage to the second stage and in which the breathable gas moves,

wherein the pressure reducing system includes:

a conduit for supplying the breathable gas under pressure;

a mouthpiece for inspiration of the breathable gas by a user;

a valve poppet operatively interposed between the conduit and the mouthpiece,

the valve poppet being movable between:

a closed position, in which the valve poppet prevents passing of the breathable gas from the conduit to the mouthpiece, and

at least one open position in which the valve poppet permits the passing of the breathable gas from the conduit to the mouthpiece,

said conduit comprising an abutment against which the valve poppet abuts in the closed position and from which the valve poppet is distanced in said at least one open position, and

said abutment defining an annular interface which in the closed position is in contact with the valve poppet in order to perform a fluid-dynamic sealing action that prevents the passing of the breathable gas from the conduit to the mouthpiece,

the annular interface being located on an end surface of the abutment; and

a balancing chamber that defines a balancing zone, the balancing chamber during operation enabling at least a partial balancing of the force exerted by the pressure of the breathable gas on the valve poppet at the abutment, said valve poppet being at least in part interposed between the abutment and the balancing chamber; the valve poppet defining a passage that places the conduit and the pressure balancing chamber in fluid communication even in the closed position of the valve poppet, wherein a section of said passage, in at least one of said open positions extends in the conduit beyond said annular interface; and wherein said passage extends in the conduit beyond said annular interface in all of said open positions of the valve poppet.

11 . A method of pressurization, the method comprising:

providing a pressure reducing system that includes:

a conduit for supplying a breathable gas under pressure;

a mouthpiece for inspiration of the breathable gas by a user;

a valve poppet operatively interposed between the conduit and the mouthpiece,

the valve poppet being movable between:

a closed position, in which the valve poppet prevents passing of the breathable gas from the conduit to the mouthpiece, and

at least one open position in which the valve poppet permits the passing of the breathable gas from the conduit to the mouthpiece,

said conduit comprising an abutment against which the valve poppet abuts in the closed position and from which the valve poppet is distanced in said at least one open position, and

said abutment defining an annular interface which in the closed position is in contact with the valve poppet in order to perform a fluid-dynamic sealing action that prevents the passing of the breathable gas from the conduit to the mouthpiece; and

a balancing chamber that defines a pressure balancing zone, said valve poppet being at least in part interposed between the abutment and the balancing chamber; the valve poppet defining a passage that places the conduit and the balancing chamber in fluid communication, wherein a section of said passage, in at least one of said open positions extends in the conduit beyond said annular interface;

when the valve poppet is distanced from the abutment and the pressure reducing system is depressurized, the method comprising the steps of:

supplying the breathable gas under pressure along the conduit; and

intercepting at least a part of the breathable gas coming from the conduit through said passage which extends beyond said annular interface and conveying the part of the breathable gas to the balancing chamber in order to bring said valve poppet into contact with said abutment and close off the passing of the breathable gas from the conduit to the mouthpiece.