SYSTEM FOR CONTROLLING THE EXHALATION PRESSURE OF A DIVER FOR DIVING VENTILATION EQUIPMENT

Abstract

A system for controlling the exhalation pressure of a diver for diving equipment with a ventilation circuit, includes a unidirectional valve acting on an exhalation outlet of the ventilation circuit, and a brake configured to exert an adjustable constraint on the unidirectional valve in order to control the pressure of the gas from the exhalation outlet so as to generate a positive exhalation pressure in the ventilation circuit of the equipment and thus prevent or treat immersion pulmonary edemas.

Claims

1. A system for controlling the expiratory pressure of a diver for diving equipment having a ventilation circuit, comprising: a one-way valve acting on an expiratory outlet of the ventilation circuit; and a brake configured to apply an adjustable constraint to the one-way valve so as to control the pressure of the gas coming from the expiratory outlet so as to generate a positive expiratory pressure in said breathing circuit.

2. The system for controlling the expiratory pressure of a diver as claimed in claim 1, wherein said brake is an adjustable discharge valve comprising a loading spring and a calibration screw allowing the resistance of said spring to be adjusted.

3. The system for controlling the expiratory pressure of a diver as claimed in claim 1, additionally comprising a release system allowing said brake to be deactivated.

4. The system for controlling the expiratory pressure of a diver as claimed in claim 3, wherein the release system comprises a central tubular rod coaxial with said calibration screw.

5. The system for controlling the expiratory pressure of a diver as claimed in claim 1, additionally comprising a pressure sensor sensing pressure in the expiratory circuit of said ventilation circuit.

6. The system for controlling the expiratory pressure of a diver as claimed in claim 5, wherein the brake is an electrically operated valve, the electrically operated valve being controlled electronically on the basis of measurements supplied by the pressure sensor. (Original) The system for controlling the expiratory pressure of a diver as claimed in claim 6, wherein the brake comprises eyes or shutters or a diaphragm.

8. The system for controlling the expiratory pressure of a diver as claimed in claim 7, wherein the degree of opening of the eyes or of the shutters or of the diaphragm is controlled electronically on the basis of measurements supplied by the pressure sensor.

9. The system for controlling the expiratory pressure of a diver as claimed in claim 1, wherein the brake allows the generation of at least two discrete positive expiratory pressure levels.

10. The system for controlling the expiratory pressure of a diver as claimed in claim 1, wherein the brake allows the generation of positive expiratory pressure levels from among the levels (0 mbar; 2.5 mbar; 5 mbar; 7.5 mbar and 10 mbar).

11. A regulator for diving, comprising at least: a first stage for expanding a high-pressure gas in order to obtain a medium-pressure gas, and a second stage able to receive said medium-pressure gas and drop the pressure of said medium-pressure gas in order to supply low-pressure gas to a diver who can be ventilated, wherein the second stage of the regulator comprises a system as claimed in claim 1 for controlling the expiratory pressure of the diver.

12. A rebreather for diving comprising a system for controlling the expiratory pressure of a diver as claimed in claim 1.

13. A self-contained underwater breathing apparatus comprising a system for controlling the expiratory pressure of a diver as claimed in claim 1.

Description

[0022] Further features, details and advantages of the invention will become apparent from reading the description given with reference to the attached figures provided by way of example and which respectively depict:

[0023] FIG. 1: an illustration, viewed from above, of the implementation of a system for controlling expiration on a regulator according to one embodiment of the invention;

[0024] FIG. 2: an illustration in section of the implementation of a system for controlling expiration on a regulator according to one embodiment of the invention;

[0025] FIG. 3: an illustration of the implementation of a system for controlling expiration on a rebreather according to one embodiment of the invention.

[0026] As is generally accepted, diving equipment may comprise all or part of a diving hardware assembly including an isothermal suit, a mask, fins, weights, a buoyancy compensator and at least one diving cylinder containing a mixture of breathing gas, such as nitrox, heliair, hydrox, trimix, heliox and hydreliox. Usually, the gas mixture is compressed air. The diving equipment within the meaning of the invention comprises a regulator or a rebreather allowing the diver to breathe through a mouthpiece.

[0027] A regulator is a piece of open-circuit diving equipment allowing a diver to breathe the gas contained in his diving cylinder at the pressure at which he is moving around.

[0028] A rebreather is an item of closed-circuit diving equipment allowing the gas exhaled by a diver to be recirculated in order to lengthen the dive time and reduce the weight of the diving cylinders.

[0029] A self-contained underwater breathing apparatus is generally defined as being an individual device that allows its user to breathe and move around freely underwater with a reserve of compressed breathing gas.

[0030] FIG. 1 shows a view from above of the second stage of a regulator according to one embodiment of the invention. A medium-pressure gas arrives from the first stage of the regulator to the second stage via a hose 100. A knob 101 allows the flow of gas arriving in the second stage via the hose 100 to be regulated. This medium-pressure gas enters the dry chamber 102 of the second stage of the regulator and is then expanded on reaching the mouthpiece 104. It is the diver inhaling in the mouthpiece 104 that triggers the passage of the gas from the dry chamber 102 to the mouthpiece 104. The inhalation or exhalation of the diver controls, for example, the opening of a valve that allows the gas to pass from the dry chamber 102 to the mouthpiece 104 during inhalation or the gas to be blocked in the dry chamber 102 during exhalation. The pressure of the exhaled gas can be adjusted using a brake 105 and the exhaled gas is discharged from the second stage of the regulator via the twin exhalent tubes 106.

[0031] FIG. 2 shows a cross section of the second stage 20 of a regulator according to one embodiment of the invention. The arrows indicate the movement of the gas in the second stage of the regulator. In this implementation, the brake 105 comprises a calibration screw 200 and a loading spring 201. The brake 105 acts on washers 202 which act on membranes 203. The membranes 203 and the washers 202 thus form a one-way valve 204. The diver is able to act upon the calibration screw 200 to adjust the resistance of the loading spring 201. During the inhalation phase, the gas present in the dry chamber 102 enters the mouthpiece via the opening of the membranes 203. During the exhalation phase, the membranes 203 close again, completely or in part according to the resistance of the loading spring 201, and the exhaled gas is removed via the twin exhalent tubes 106. By controlling the degree of closure of the membranes, by adjusting the resistance of the loading spring 201, in order to have full or partial closure, the diver is able to alter the pressure of the exhaled gas.

[0032] The clinical manifestations of immersion pulmonary edema often occur during the reascent phase or when the diving session is extended. They do not therefore always occur at the same moment or with the same intensity in all divers. It is therefore important to be able to regulate the positive expiratory pressure as soon as symptoms start to appear, or even to anticipate the onset of edema through preventative triggering as soon as the environmental conditions become restrictive. In the embodiment described, the diver acts directly on the calibration screw 200 according to how he feels.

[0033] Furthermore, during reascent, the act of the diver adopting a more vertical attitude leads to a large difference in pressure between the regulator which is in the diver's mouth and his lungs. It is therefore necessary to generate a greater positive expiratory pressure than during descent in order to prevent immersion pulmonary edema or treat the symptoms thereof.

[0034] The second stage of the regulator may also comprise a release rod 205 which allows the brake to be deactivated, namely allows the resistance of the loading spring 201 to be canceled. This release rod 205 constitutes a safety feature regarding the solid obstruction level of the system or emergency reascent requiring the absence of any impediment to exhalation. The release rod 205 is central and coaxial with the calibration screw 200. The valve 204, the brake 105 and the release rod 205 are held in place by a fixed housing 206. This fixed housing 206 also comprises a safety release duct 207.

[0035] In a variant embodiment of the invention, a pressure sensor is positioned in the expiratory circuit to measure the pressure of the gas exhaled by the diver. According to one embodiment, the sensor may be positioned at the mouthpiece 104.

[0036] Advantageously, measurements can be collected for electronically controlling the brake 105. Electronic control of the brake allows more effective detection of any symptom associated with the onset of pulmonary edema and allows any expiratory-pressure control action to be generated more rapidly. In an embodiment involving an inbuilt sensor, the brake 105 is an electrically operated valve or solenoid valve. The brake may also be made up of eyes, of shutters or may be a diaphragm, the eyes, the shutters and the diaphragm being outlet orifices having a variable degree of opening. More generally, the brake may adopt any form that allows the degree of closing-off of the outlet area to be varied.

[0037] Thus, the system comprises two modes of operation: one referred to as passive and the second referred to as active. The passive mode is characterized by the absence of positive expiratory pressure and is the mode favored for the descent of the diver or may be the mode imposed in the event of an emergency reascent in which exhalation needs to be facilitated. The other mode of operation, referred to as active mode, is characterized by the generation of a positive expiratory pressure through the implementation of the system of the invention. The active mode is used during the diver reascent phase or when the diving session is extended. The active mode can be brought into action semi-autonomously by the diver who can regulate the level of the positive expiratory pressure by activating the calibration screw, or can be brought about automatically by being for example automatically controlled by a dive computer worn by the diver. The dive computer records the diver's diving parameters and is thus able to supply data regarding the symptoms experienced by the diver so as to activate the system for controlling the expiratory pressure. In an embodiment variant, the diving equipment may comprise a plurality of sensors allowing the supply of data which may enrich the detection of symptoms indicative of immersion pulmonary edema.

[0038] According to another embodiment of the invention, the brake 105 allows the generation of at least two discrete positive expiratory pressure levels. The 0 mbar discrete level forms one of the possible levels for the positive expiratory pressure. In order to conform to the known standards, in one embodiment, the brake allows the generation of positive expiratory pressure levels from among the following levels: [0039] 0 mbar; [0040] 2.5 mbar; [0041] 5 mbar; [0042] 7.5 mbar; and [0043] 10 mbar.

[0044] Advantageously, the positive expiratory pressure levels are chosen from among the following levels: 2.5 mbar; 5 mbar; 7.5 mbar and 10 mbar.

[0045] These positive expiratory pressure values, given by way of nonlimiting example, correspond to the levels capable of preventing the onset of pulmonary edema in emergency medicine while at the same time not achieving levels liable to create pulmonary overpressure and conforming to pressure regime limits for regulators (see standard NF EN 250, June 2014). FIG. 3 shows the implementation of one of the embodiments of the invention on a diving rebreather. The arrows indicate the movement of the gas through the rebreather. When the diver inhales, the rebreather supplies the diver with gas from the inhalation breathing sack 300. This gas reaches the mouthpiece 301 via a hose 302. In the mouthpiece 301, the inhaled gas passes through an inhalation non-return valve 303 before reaching the diver's mouth. When the diver exhales, the exhaled gas enters the mouthpiece 301 and passes through the exhalation non-return valve 304. A brake 305 that can be adjusted by the diver allows him to influence the opening of this valve 304. By limiting its opening, the brake 305 can generate a positive expiratory pressure in the mouthpiece 301, allowing immersion pulmonary edema to be prevented or treated.

[0046] Having passed through the exhalation non-return valve 304, the exhaled gas arrives at the exhalation breathing sack 306 via a hose 302. One or more breathing gas cylinders 307 supply the exhalation breathing sack 306 with breathing gas (this supply is indicated by the reference 308 in FIG. 3). The gases then present in the exhalation breathing sack 306 pass through a filter 309. This filter 309 filters out the carbon dioxide so that the gases that then enter the inhalation breathing sack 300 no longer contain carbon dioxide.

[0047] The invention has been described for a number of embodiments in order to illustrate the general principle thereof. However, those skilled in the art will be able to adapt the invention to other embodiments without diverging from the essential features described here. More generally, the invention can be used on any type of open or closed diving circuit. The embodiments described need to be considered in all respects to be purely illustrative and nonlimiting.