FR2842495A1 - Safety isobaric sub-aqua breathing device for diver includes a buoy floating on the water surface and passing atmospheric air via a flexible tube to a mouth breathing piece - Google Patents

Abstract

The breathing device includes a buoy (1) on the water surface for passing atmospheric air via a flexible tube (2) to a diver's mouth piece (3), enabling the diver to breath fresh air while expelling used air into the water via an outlet valve (12). Filling of a variable volume (5) of air, in a rigid enclosure (6), is maintained by a hydraulic outlet (9) and a hydrostatic valve (13) that ensures via control device (11), connected to a filling detector and a breathing detector, automatic ultra quick filling of the volume of air to maintain a maximum volume of breathable air.

Description

The invention relates to the field of diving and, more

  particularly, in the field of the means used by man to move underwater, over distances and at depths quite limited but much greater than what would allow a snorkeling for a subject who would not be specially trained . More particularly, the invention relates to a device allowing man to carry out underwater explorations of limited range, both in depth and in journey, for example recreational or reconnaissance dives, without the need to rise to the surface to breathe and, more specifically still, the invention relates to an isobaric device for underwater safety breathing, allowing, in

  in addition, permanently locate the immersion diver.

  Essentially, to date, breathing apparatus for divers is known, supplied either by means of diving cylinders containing breathable gas under high pressure, or, from the surface, by a device of the hookah type, simple regulator worn by the diver or by a submerged or installed air compressor, for example, on board a boat, such as those covered by documents DD 124 174 A, DE 101 07 477 A and US 3,124,131. These devices of the prior art have several major drawbacks. In addition to their volume, therefore their bulk, and their mass or the displacement limit in the event of the use of a compressor, they have insufficient safety due to the risks run by the diver in the event of a malfunction of one of the vital organs, the compressor can for example suck in exhaust gases if it is driven by a heat engine or seize up

  penetration of seawater into the gas compression circuit.

  The technical problems to be solved are, therefore, above all, the problem of the safety of the diver, on the one hand by ensuring his supply of breathing air in equilibrium with the ambient aqueous medium, on the other hand by authorizing a permanent monitoring function , and that of the possibility of overcoming the constraints linked to the use of an on-board air compressor which requires permanent treatment to rid the air of impurities such as oil or metallic particles or those linked to the use of a gas cylinder

compressed, heavy and bulky.

  Consequently, the first objective of the invention is aimed at total safety of the diver, by proposing an isobaric device for underwater safety breathing, simple ensuring, from atmospheric air, the direct supply of said diver with breathable air at the hydrostatic pressure at which it evolves, a device of economic design and construction, which also allows constant monitoring of the diver thanks to the additional permanent signaling function provided by a surface buoy with air intake atmospheric, an integral part of said isobaric breathing device

underwater security.

  To do this, the invention is an isobaric device for underwater safety breathing comprising a surface buoy with atmospheric air intake connected, via a flexible hose to a mouthpiece breathing mouthpiece, associated with a regulator, allowing the diver to breathe in fresh air and breathe out the stale air directly into the water via a stale air exhalation valve, said isobaric device comprising a variable volume of air , characterized in that said variable air volume is enclosed in a rigid enclosure of constant volume and in that the automatic filling of said variable air volume is managed by a hydraulic emptying device and by a hydrostatic valve which, thanks to to a control logic in conjunction with a variable air volume filling detector coupled with an inspiration detector arranged in said regulator, the ultra-fast automatic filling of said volume ir variable, which allows said 25 diver to have, permanently, a reserve of breathable air, at the pressure at which it is located, reserve equal to the capacity of said volume

variable air.

  The function of the hydraulic emptying device is to create, in the rigid enclosure, a pressure slightly lower than atmospheric pressure, which results in the filling of the variable air volume, by

  air from the surface through the flexible hose.

  Depending on the variant, the hydraulic emptying device can consist of a water pump or a hydraulic suction device with a venturi effect or any other emptying system.

equivalent hydraulics.

  In a variant of the isobaric safety underwater breathing device, the variable air volume consists of a more or less large fraction of said rigid enclosure, fraction

  delimited by the displacement of a movable piston.

  In another variant of the isobaric safety underwater breathing device, the variable air volume consists of a more or less large fraction of said rigid enclosure, fraction delimited by a flexible membrane whose ends are integral with the

walls of the rigid enclosure.

  In another variant of the isobaric safety underwater breathing device, the variable air volume consists of a more or less large fraction of said rigid enclosure, fraction equal to

  the capacity of a flexible breathing bag enclosed in said rigid enclosure.

  Most of the preceding variants of the isobaric safety underwater breathing device according to the invention are equipped with a pump to ensure the emptying of the water contained in the fraction of the rigid enclosure free of breathable air and of '' a hydrostatic valve for setting the variable air volume to the ambient hydrostatic pressure. In some variants, the hydrostatic valve is a solenoid valve, in other variants, the function of said hydrostatic valve is ensured by the hydraulic emptying device itself, either that it is slightly modified to include an integrated hydrostatic valve or either that he

  itself behaves like a hydrostatic valve when inactive.

  In still other variants, the hydraulic emptying device is not integral with the rigid enclosure including the variable air volume, the pump being able to be placed in the surface buoy, or even in the case of a hydraulic suction system with Venturi effect

  supplied with water by a pump itself arranged on the surface.

  Associated or not with the preceding variants, a variant making it possible to increase the comfort of the diver consists in inserting, in the respiratory circuit, between the outlet of the variable air volume and the nozzle.

  respirator associated with the regulator, a separate non-return valve.

  The invention will be better understood on reading the description

  accompanying the drawings, in which: FIG. 1 explains the operating diagram of the device

  safety underwater breathing isobar.

  FIG. 2 schematically shows, in a variant of the isobaric device for underwater safety breathing, according to the invention, the variable air volume consisting of a more or less large fraction of the rigid enclosure, fraction delimited by the displacement d 'a movable piston. FIG. 3 schematically describes, in another variant of the isobaric device for underwater safety breathing, according to the invention, the variable air volume consisting of a more or less large fraction of the rigid enclosure, fraction delimited by a membrane flexible whose

  ends are integral with the wall of said rigid enclosure.

  FIG. 4 schematically illustrates, in a variant of the isobaric device for underwater safety breathing, according to the invention, the variable air volume consisting of a more or less large fraction of said rigid enclosure, fraction equal to the capacity of a breathing bag

  flexible enclosure in said rigid enclosure.

  FIG. 5 details the constitution and operation of the regulator associated with the mouthpiece respirator, said regulator consisting of a hydrostatic respiratory chamber mounted, on the respiratory circuit, between said mouthpiece respirator and the valve

stale air expiration.

  FIG. 6 provides a diagram of a variant of the isobaric safety underwater breathing device according to the invention, in

  which a separate valve is arranged in the respiratory circuit.

  Figures 7a and 7b illustrate the operating principle

  of a variant of the hydrostatic breathing chamber.

  FIG. 8 schematically shows an arrangement of the elements of a variant of the isobaric safety device in which the hydraulic emptying device is no longer integral with the rigid enclosure

including variable air volume.

  FIG. 9 describes a variant of the isobaric safety device o a hydraulic suction system with a venturi effect, powered by a pump, ensures the suction of the water contained in the rigid enclosure including

the variable air volume.

  FIG. 10 schematically illustrates the operation of the hydraulic suction system with a venturi effect supplied with pressurized water by means of a pump. Figure 1 explains the operating diagram of the device

  safety underwater breathing isobar.

  Said device comprises a surface buoy with atmospheric air intake (1) intended to permanently maintain, in ambient air, the end of a flexible pipe (2) connected to a mouthpiece breathing mouthpiece (3), by means of a non-return valve (4) and a variable air volume (5) in a rigid enclosure (6) provided with a variable air volume filling detector (7) having for the purpose of keeping said variable volume of air (5) permanently filled, when the device is submerged, and of a hydraulic emptying device (9) and of a hydrostatic valve (13) controlled by a logic of control (11). A stale air exhalation valve (12) allows the plunger to exhale,

  directly into the water, stale air.

  The variable air volume (5) is arranged as a bypass of the part of the respiratory circuit located between said non-return valve (4) and said

mouthpiece mouthpiece (3).

  The isobaric safety underwater breathing device according to the invention therefore allows the diver to breathe fresh air contained in the variable air volume (5) supplied continuously from the surface with air at the atmospheric pressure through the flexible hose (2). The surface buoy with atmospheric air intake (1) also provides a permanent signaling function for the location of the submerged diver, which further increases safety. A controlled valve (21) allows the diver to drop his mouthpiece respirator (3), underwater, without the variable air volume (5) being flooded by the water of the

ambient.

  To be able to check, on the ground or on the surface, the proper functioning of the device, the different variants can be equipped with a spring (8) contained in the rigid enclosure (6) which allows to keep filled, in the open air, the variable air volume (5). An aquatic switch (14) prohibits the implementation of the hydraulic emptying device (9) as long as the part of the isobaric safety underwater breathing device which is connected to the surface buoy with atmospheric air intake (1) does not is not submerged. Underwater, the hydraulic emptying device (9) evacuates the water contained in the fraction of the rigid enclosure (6) free of breathable air and, therefore, automatic and ultra-rapid filling said variable volume of air (5), in the respiratory rest phases of the diver or those in which he expires stale air. A hydrostatic valve (13), of the solenoid valve type (1 5) or hydrostatic valve integrated (16) in said hydraulic emptying device (9), ensures the communication between the ambient aqueous medium and the variable air volume (5 ) when the diver breathes, or the isolation between the ambient aqueous medium and the water contained in the rigid enclosure (6) containing the variable volume of air (5) when the diver is in the respiratory rest phase or expiration, which allows the hydraulic drain device (9) to evacuate the water contained in said rigid enclosure (6), and has the effect of filling said variable air volume (5). Said hydrostatic valve (13, 15 or 16) is therefore maintained, by the control unit (11), in the open position as long as the hydraulic drain device (9) is inactive and it is kept in the closed position when the drain device hydraulic (9) works and the variable air volume (5) is filled. The hydraulic drain device (9) stops operating as soon as said variable air volume (5) reaches its maximum capacity, which is detected by the volume filling detector.

variable air (7).

  The diver, in immersion, takes the mouthpiece breathing mouthpiece (3) in the mouth and inhales the fresh air, at the pressure at which it evolves, contained in the variable volume of air (5). The stale air exhalation valve (12) is then closed, which prevents water from the ambient environment from

  enter the respiratory circuit through said mouthpiece respirator (3).

  As soon as the part of the isobaric safety underwater breathing device connected to the surface buoy with atmospheric air intake (1) is immersed, the variable air volume (5) comes into contact with the water in the ambient environment thanks to hydrostatic valve (13, 15 or 16) kept open. The non-return valve (4) then prohibits emptying

  air contained in the variable air volume (5) towards the surface.

  The aquatic switch device (14) authorizes the start-up of the hydraulic emptying device (9) as soon as the variable air volume filling detector (7) detects a reduction in filling of said variable air volume (5 ) in relation to full capacity, whether due to the inspiration of the air by the diver or, under the effect

  pressure, following the descent of said plunger at depth.

  This has the effect of causing the fraction of the rigid enclosure (6) free of breathable air to be filled with water from the ambient medium passing through the hydrostatic valve (13, 15 or 16) maintained in the open position. However, for safety reasons, the hydraulic emptying device (9) can only be engaged if the inspiration detector (17) signals to the control unit (11) to which it is connected that the plunger is either in the respiratory rest phase or in the expiration phase of stale air. As soon as the two conditions are simultaneously fulfilled, i.e. the decrease in the variable air volume (5) and the occurrence of the phase during which the diver does not breathe, the hydrostatic valve (1 3, 1 5 or 16) closes and, simultaneously, the hydraulic emptying device (9) engages and discharges the water contained in the space of the rigid enclosure (6)

free of breathing air.

  In doing so, the vacuum action induced by the operation of said hydraulic emptying device (9) has the effect of filling said variable air volume (5) with air coming from the surface, thanks to the flexible hose (2 ) via the non-return valve (4). There is a vacuum because the hydraulic drain device (9) is active but the hydrostatic valve (13, 15 or 16) is closed which prevents water from

  ambient medium to enter the rigid enclosure (6).

  Said hydraulic emptying device (9) is dimensioned so that the suction of the quantity of water contained in the space of the rigid enclosure (6) free of breathing air, when the variable air volume (5) is no longer completely full, or very fast, i.e. around two seconds. Therefore, said variable air volume (5) is kept full of air almost permanently. In other words, whatever the situation, the diver, with a wait limited to a few seconds, has, in

  permanently, of a variable air volume (5) full of breathable air.

  The diver exhales, in the ambient aqueous medium, the stale air contained in his lungs through the mouthpiece breathing mouthpiece (3) and

  of the stale air exhalation valve (1 2).

  Whatever the depth and configuration of the dive and, particularly in the event of a sudden ascent of the diver, the apparent mass of the assembly consisting of the diver and the isobaric safety underwater breathing device according to the invention remains constant because the capacity of the variable air volume (5) cannot exceed

  the interior volume of the rigid enclosure (6).

  During the ascent, normal or rapid, the excess air in the variable air volume (5) d when the hydrostatic pressure drops, is evacuated outside the respiratory circuit by a relief valve ( 18), without passing through the mouthpiece breathing mouthpiece (3), as long as the plunger

does not engage in inspiration.

  FIG. 2 schematically shows, in a variant of the isobaric safety underwater breathing device, according to the invention, the variable air volume (5), consisting of a more or less large fraction of the rigid enclosure (6) , fraction delimited by displacement

a movable piston (23).

  In the variant shown, said rigid enclosure (6) comprises a hydrostatic valve (13) and a filling detector for the variable air volume (7) and is in relation with the hydraulic emptying device (9). The operation of the hydrostatic valve (13), the variable air volume filling detector (7) and the hydraulic emptying device (9) are managed by the control unit (11). The hydrostatic valve (13) is maintained, by said control logic (11) in the open position as long as the hydraulic drain device (9) is inactive and in the closed position when said hydraulic drain device (9)

  works and the variable air volume (5) is filled.

  When said hydraulic emptying device (9) has evacuated the water contained in the rigid enclosure (6), the movable piston (23) is in the high position in the rigid enclosure (6) and the variable air volume (5) is maximum. The variable air volume filling detector (7) controls, via the control logic (11), the stopping of the hydraulic drain device (9) and the opening of the hydrostatic valve (13). As the plunger inhales the air contained in said variable volume of air (5), the water from the ambient medium enters the rigid enclosure (6) and the movable piston (23) moves towards the low position, that is to say towards the bottom of said rigid enclosure (6). The variable air volume filling detector (7) then triggers, via the control logic (11), the closing of the hydrostatic valve (13) and the putting into operation of the hydraulic emptying device (9) which evacuates water from the part of said rigid enclosure (6) free of breathable air and the

cycle begins again.

  In a variant not shown, the role of the hydrostatic valve can be performed by the hydraulic drain device (9) itself, which has been slightly modified for this purpose to include an integrated hydrostatic valve (16). Therefore, the hydrostatic valve (13) and its connection with the control unit (11) no longer need to be and said hydraulic drain device (9) behaves like an open valve

when it is inactive.

  FIG. 3 schematically describes, in another variant of the isobaric underwater safety breathing device, according to the invention, the variable air volume (5), consisting of a more or less large fraction of the rigid enclosure (6 ), fraction delimited by a flexible membrane (24) whose ends are made integral with the wall of said

rigid enclosure (6).

  The operation of this variant of the invention is similar to that described in FIG. 2, with the difference that the vertical displacement of the movable piston (23) in the rigid enclosure (6) is replaced by the deformation of the flexible membrane (24 ) whose length and width, in the middle position, are greater than the corresponding dimensions of

the rigid enclosure (6).

  As in the variant not shown but described in Figure 2, the role of the hydrostatic valve (13) can be performed by the hydraulic drain device (9) itself, comprising the integrated hydrostatic valve (16); it follows that the hydrostatic valve (13) and its connection

  with the control unit (1 1) are no longer necessary.

  FIG. 4 schematically illustrates, in a variant of the isobaric safety underwater breathing device, according to the invention, the variable air volume (5), consisting of a more or less large fraction of said rigid enclosure (6), fraction equal to the capacity of a flexible breathing bag (25) enclosed in said rigid enclosure (6). Said flexible breathing bag (25) is integral with the wall of said rigid enclosure (6) opposite to that which includes the hydraulic emptying device (9) to avoid that during the water evacuation phase, said breathing bag flexible (25) does not block the inlet of said drain device

hydraulic (9).

  The operation of this variant of the invention is similar to those described in Figures 2 and 3, with the difference that the vertical displacement of the movable piston (23) and the deformation of the flexible membrane (24) in the rigid enclosure (6 ) are replaced by

  filling or emptying said flexible breathing bag (25).

  As in the variants not shown but described in Figures 2 and 3, the role of the hydrostatic valve (1 3) can be ensured by the hydraulic drain device (9) itself, comprising an integrated hydrostatic valve (16), the valve hydrostatic (13) and its connection with the

  control logic (1 1) then no longer have a raison d'être.

  Figure 5 details the constitution and operation of the regulator associated with the mouthpiece mouthpiece (3) and consisting of a hydrostatic breathing chamber (19) mounted, on the respiratory circuit, between said mouthpiece mouthpiece (3) and a valve expiration of

stale air (1 2).

  The wall of said hydrostatic breathing chamber (1 9) in contact with the ambient aqueous medium consists of a flexible hydrostatic membrane (22) connected, via a connecting rod (26) to a controlled valve (21 ). The air inspiration by the plunger causes the displacement, towards the inside of said hydrostatic breathing chamber (19) of said flexible hydrostatic membrane (22) which, by means of said connecting rod (26), causes l opening of the controlled valve (21). Therefore, said controlled valve (21) being open, the breathable air from the variable air volume (5) of the rigid enclosure (6) can enter the hydrostatic breathing chamber (1 9) and ensure the breathing of the air plunger at hydrostatic pressure from the variable air volume (5). As soon as the diver stops inhaling or exhaling stale air, in the ambient aqueous medium, by means of the stale air exhalation valve (12) the flexible hydrostatic membrane (22) resumes its initial position which causes the controlled valve (21) to close. The inspiration detector (17), linked to the control unit (11), therefore signals that the diver is in the respiratory rest or expiration phase and authorizes the operation of the

hydraulic drain (9).

  FIG. 6 provides a diagram of a variant of the isobaric safety underwater breathing device according to the invention, in which a separate valve (27) is arranged, in the respiratory circuit, outside the hydrostatic respiratory chamber ( 19), as shown, or

  integrated into it, to increase the comfort of the diver.

  The respiratory circuit comprises, from the surface buoy with atmospheric air intake (1), the flexible tube (2) connected to the mouthpiece breathing mouthpiece (3), the non-return valve (4), the volume of variable air (5) included in the rigid enclosure (6) provided with the variable air volume filling detector (7) and connected to a hydraulic emptying device (9) and equipped with a controlled hydrostatic valve (13) by a control logic (11). A stale air exhalation valve (12) allows the

  diver to exhale, directly into the water, stale air.

  The hydraulic emptying device (9) ensures the evacuation of the water contained in the fraction of the rigid enclosure (6) free of breathable air and, therefore, the automatic and ultra-rapid filling of said volume of air. variable (5), in the respiratory rest phases of the diver or those where he expires stale air. The separate valve (27) is arranged in or near the hydrostatic breathing chamber in order to increase the comfort of the diver and to avoid the unpleasant suction effects which occur during the operation of the device.

hydraulic drain.

  Indeed, as soon as the decrease in the variable air volume (5) and the occurrence of the phase during which the plunger does not breathe, the hydraulic drain device (9) engages and evacuates the water contained

  in the space of the rigid enclosure (6) free of breathable air (5).

  Said hydraulic emptying device <9) then fills said variable air volume (5) with air coming from the surface, by means of the flexible pipe (2) via the non-return valve (4) of said volume. variable air (5), because the hydrostatic valve (13, 15 or 16) is closed which prevents water from the ambient environment from entering the rigid enclosure (6)

  as long as the motor of the hydraulic drain device (9) is active.

  As shown, the variable air volume (5) can be arranged in series with the part of the respiratory circuit located between said valve.

  non-return valve (4) and said mouthpiece respirator (3).

  Figures 7a and 7b illustrate the operating principle of a variant of the hydrostatic breathing chamber (19) which comprises, in the vicinity of the mouthpiece breathing mouthpiece (3), an inspiration detector

  (17) which is activated by the displacement of the hydrostatic membrane (22).

  View 7a shows the position of the elements of the hydrostatic respiratory chamber (19) in the respiratory rest phase of the plunger, the metal patch (29) integral with the hydrostatic membrane (22) does not

  not being, then, in contact with said inspiration detector (17).

  View 7b illustrates the operation of said chamber

  hydrostatic respiratory system (19) during the suction of fresh air by the diver.

  The air intake creates a depression in said hydrostatic breathing chamber (19) which causes the inward movement of the hydrostatic membrane (22). The metal chip (29), which is integral therewith, then comes into contact with the inspiration detector (17) connected to the

  control logic (1 1) and makes it active. Figure 8 schematically shows an arrangement of the elements of a

  variant of the isobaric safety device in which the hydraulic emptying device is no longer integral with the rigid enclosure

including variable air volume.

  In the variant shown, the hydraulic emptying device (9) is located in the surface buoy with air intake (1), the flexible hose (2) has become a double hose, the air intake in the volume variable air (5) through the pipe (2a), the water outlet from the rigid enclosure (6) through the pipe (2b), the rest of the components and the

operation remaining identical.

  FIG. 9 describes a variant of the isobaric safety device o the hydraulic emptying device (9) consists of a Venturi system which ensures the suction of water from the rigid enclosure (6) including the volume of variable air (5). Said Venturi system is composed of a Venturi cone (28), supplied with pressurized water by a pump (30) thanks

to the flexible hose (2b).

  In the variant illustrated, the hydraulic emptying device (9) is not integral with the rigid enclosure (6) and is not disposed in the surface buoy with air intake (1), although a such an arrangement is feasible. The hydrostatic valve (referenced 13, in Figure 1) is no longer essential, the Venturi cone (28) allowing water to enter the rigid enclosure when the pump (30) is inactive. Which induces important

  advantages of lightening and ease of implementation.

  The operating principle of the hydraulic drain device (9) consisting of a Venturi system is illustrated

schematically in Figure 10.

  Under the effect of the pressurized water sent by the electric pump (30) into the Venturi cone (28) via the flexible pipe (2b), a suction hydraulic current occurs creating a vacuum at the interior of said rigid enclosure (6), thereby allowing

  the variable air volume (5) to resume its maximum volume.

  Preferably, in all the variants, represented or not, a rapid ascent detector (20) is coupled to an alarm emitting an audible signal at the mouthpiece breathing mouthpiece (3) to avoid any risk of pulmonary overpressure. This sound signal is intended to remind the diver that in the event of a rapid ascent, he should never block his expiration. This set of ascent detector

  rapid and audible signal further increases the safety of the diver.

  The isobaric underwater breathing device, object of the invention, offers, compared to the known solutions of the prior art, multiple advantages, among which the main ones are, essentially: - safety, by providing, almost permanently , to the plunger of breathable air at hydrostatic pressure via the variable air volume in the rigid enclosure, allowing rapid ascent without risk of pulmonary overpressure, thanks to a relief valve and allowing, by in addition, the permanent location of the diver, thanks to the surface buoy with atmospheric air intake; - increased comfort and mobility of the diver, thanks to the lighter weight of the entire device, thanks to the low-mass hydraulic drain device and the compactness of all the components; In summary, it is quite obvious that the isobaric safety underwater breathing device according to the invention solves the safety problems of dives of limited depth and distance,

  by offering, in its various variants and combinations, a safe, light and economical device to make.

  It is obvious that a person skilled in the art will be able to combine the 20 different variants of the isobaric safety underwater breathing device which is the subject of the invention, or use equivalent means, without

depart from the scope of the invention.

Claims (18)

  1 - Isobaric underwater safety breathing device comprising a surface buoy with atmospheric air intake (1) connected, via a flexible pipe (2) and a non-return valve (4) to a mouthpiece breathing mouthpiece (3) associated with a regulator, and with a variable air volume (5), allowing the diver to breathe in fresh air and to expire stale air directly into the water through the via a stale air exhalation valve (12), characterized in that said variable air volume (5) is enclosed in a rigid enclosure (6) at constant volume and in that the automatic filling of said variable air volume (5) is managed by a hydraulic emptying device (9) and by a hydrostatic valve (13) which, thanks to a control logic (11) in connection with a volume filling detector variable air (7) and with an inspiration detector (17), placed in said regulator, ultra-automatic filling of said variable volume of air (5), which allows said diver to have, almost permanently, a   reserve of breathable air, at the pressure at which it evolves, reserve equal to the maximum capacity of said variable volume of air (5).   2- isobaric safety underwater breathing device according to claim 1, characterized in that the hydraulic emptying device (9) behaves, in itself, as an integrated hydrostatic valve (16),   so that when it is inactive, the water in the ambient medium is in communication with the interior of the rigid enclosure (6).   3 - Isobaric device for underwater safety breathing, according to one of claims 1 or 2, characterized in that the device   hydraulic drain (9) is fixed to the rigid enclosure (6), the air supply being made by the flexible pipe (2).   4 - Isobaric safety underwater breathing device according to one of claims 1 or 2, characterized in that the hydraulic emptying device (9) is distant from the rigid enclosure (6), either in the surface buoy with air intake (1), or in its vicinity, the air supply being made by the flexible hose (2a), the water intake being made by the hose flexible (2b).   in air using the flexible hose (2a), the water being drawn in by the flexible hose (2b).   - Isobaric device for underwater breathing,   according to one of claims 1 to 4, characterized in that the device for   hydraulic drain (9) is a water pump.   6 - Isobaric device for underwater breathing,   according to one of claims 1 to 4, characterized in that the device for   hydraulic drain (9) is a suction system with venturi effect.   7 - Isobaric underwater safety breathing device according to claim 6, characterized in that the hydraulic emptying device (9) is a suction system with venturi effect supplied with air   or in water, from the surface, through the flexible hose (2b).   8 - Isobaric device for underwater breathing,   according to one of claims 1 to 7, characterized in that the air volume   variable (5) whose filling is managed by the hydraulic emptying device (9) consists of a more or less large fraction of said rigid enclosure (6), fraction delimited by the displacement of a piston mobile (23).   9 - isobaric safety underwater breathing device according to one of claims 1 to 7, characterized in that the volume of air   variable (5) whose filling is managed by the hydraulic emptying device (9) consists of a more or less large fraction of said rigid enclosure (6), fraction delimited by a flexible membrane (24)   the edges of which are integral with the walls of the rigid enclosure (6).   - Isobaric device for underwater breathing,   according to one of claims 1 to 7, characterized in that the air volume   variable (5) whose filling is managed by the hydraulic emptying device (9) consists of a more or less large fraction of said rigid enclosure (6), fraction equal to the capacity of a flexible breathing bag (25) enclosed in said rigid enclosure (6) and integral with the wall of said rigid enclosure (6).   1 1 - Isobaric safety underwater breathing device,   according to one of claims 1 to 10, characterized in that said volume   variable air (5), the filling of which is managed by the hydraulic emptying device (9) comprises a spring (8) allowing said variable volume (5) to resume its full capacity, excluding immersion, to allow verification of proper operation general, on land or on the surface, of said device.   12 - Isobaric device for underwater breathing,   according to one of claims 1 to 1 1, characterized in that the valve   hydrostatic (13) is controlled by the operation of the hydraulic drain device (9), via the control unit (11), which closes said hydrostatic valve (13) when the hydraulic drain device (9) is in works to drain the water from the rigid enclosure (6) and opens it when the hydraulic drain device (9) is not not in use.   13 - Isobaric device for underwater breathing,   according to one of claims 1 to 1 1, characterized in that the valve   hydrostatic (13) is controlled by the operation of the inspiration detector (17) via the control unit (11), which opens said hydrostatic valve (13) when the inspiration detector (17)   shows that the diver is in the inspiration phase.   14 - Isobaric device for underwater breathing,   according to one of claims 1 to 1 2, characterized in that the device for   hydraulic drain (9) is controlled by the operation of the inspiration detector (1 7) via the control unit (11), which deactivates the operation of the hydraulic drain device (9) when the inspiration detector (17) shows that the diver is in phase inspiration.   1 5 - Isobaric device for underwater breathing,   according to one of claims 1 or 3 to 14, characterized in that the valve   hydrostatic (13) is a solenoid valve (15) connected to the logic of control (11).   16 - Isobaric device for underwater breathing,   according to one of claims 1 to 15 characterized in that the regulator   is a hydrostatic breathing chamber (19) comprising a flexible hydrostatic membrane (22) which controls, by means of a connecting rod (26), the opening or closing of a controlled valve (21), depending on whether the   diver is in the inspiration or respiratory rest and expiration phase.   17- Isobaric device for underwater breathing,   according to one of claims 1 to 16, characterized in that it is equipped   a separate valve (27) for reducing the suction effects in the mouthpiece mouthpiece (3) when filling the volume variable air (5).   18 - Isobaric device for underwater breathing, according to claim 17, characterized in that the separate valve (27) replaces the controlled valve (21) as regards the reduction of the suction effects in the mouthpiece mouthpiece (3 ) when filling variable air volume (5).   19 - Isobaric device for underwater breathing,   according to one of claims 17 or 18, characterized in that the valve   separate (27) is disposed between the outlet of the variable air volume (5) and the regulator. 20 - Isobaric device for underwater breathing,   according to one of claims 17 or 18, characterized in that the valve   separate (27) is integrated into the regulator.   21 - Isobaric device for underwater breathing,   according to one of claims 1 3 to 20, characterized in that the opening and   the closing of the hydrostatic valve (13) is controlled by an inspiration detector (17) activated by a hydrostatic membrane (22) comprising a connecting rod (26) and forming one of the walls of the   hydrostatic breathing chamber (1 9).   22 - Isobaric device for underwater breathing,   according to one of claims 1 to 21, characterized in that it is equipped   a relief valve (18) allowing the evacuation of the excess air in the variable air volume (5) d at the drop in hydrostatic pressure,   in case of normal or rapid ascent of the diver.   23- Isobaric safety underwater breathing device,   according to one of claims 1 to 22, characterized in that it is equipped   a rapid ascent detector (20) coupled to an alarm emitting an audible signal at the mouthpiece mouthpiece (3) to remind the   diver that he should not block his breathing in these conditions.