FR2491428A1 - Divers breathing appts. with oxygen bottle - has diaphragm subjected to environmental pressure controlling oxygen concentration - Google Patents

Abstract

The diver's respiratory appts. comprises a mask with inlet and outlet passages contq. non-return valves and leading to a respiratory sac varying in vol. in synchronism with respiration and to bottles of compressed oxygen and inert gas. Each bottle has a diaphragm-type redn. valve calibrated by a spring and supplies the sac, which has venting and inlet devices operating with its variations in volume. The redn. valve of one bottle at least (19) works with an additional corrective diaphragm (41) exposed to the environmental pressure. This automatically alters the calibration of the valve spring (25) and reduces the concentration of oxygen admitted to the sac (17) as this pressure increases.

Description

 The present invention relates to a diving breathing apparatus, comprising a mask, suction and expiration ducts provided with non-return valves and connected both to the mask and to a breathing bag whose volume varies with the rhythm of the breathing, oxygen and inert gas bottles, for example nitrogen, under pressure, each bottle having a spring-loaded diaphragm regulator, means for supplying oxygen and inert gas to the respiratory bag from said bottles and means for purging the respiratory bag, said supply and purging means being subject to variations in the volume of the respiratory bag.

 Such a breathing apparatus is usable in deep diving and operates in a semi-closed circuit in the following known manner.

 during the expiration period, the air expelled through the expiration duct passes through carbon dioxide absorption means and inflates the respiratory bag. During the inspiration period, the inspiration conduit takes the gas mixture from the deflating respiratory bag. When this bag.

is sufficiently collapsed, the means for supplying oxygen and. inert gas from the respiratory bag introduces oxygen and inert gas into this bag, which allows the supply of the inspiration duct with a renewed mixture. during the next germ of expiration, the respiratory bag is inflated, which closes the supply of oxygen and inert gas to this respiratory bag.

 In such a diving breathing apparatus, the partial pressure of the oxygen contained in the inspired mixture must remain substantially constant or more exactly between two limit values, called safety values, for example 1.5 bar and 0.2 bar, and this to save the diver.

 It is therefore essential to provide a concentration of oxygen in the inspired mixture, the smaller the depth and therefore the surrounding pressure themselves.

 When the diver must stay at a fixed level, it suffices to adjust the bottles so that the oxygen concentration in the inspired mixture corresponds to a suitable pressure per tial of oxygen taking into account the depth of stay.

 However, divers can often swim in depths. largely variable and it is advisable, in this case, to vary the concentration of zygene in the inspired mixture so that the partial pressure of oxygen always remains within the safety limits, whatever the depth.

 To this end, diving breathing apparatus has already been proposed having means for automatically adjusting the oxygen concentration in the inspired mixture. These devices generally include an analyzer directly sensitive to the concentration of oxygen in the respiratory bag and controlling, via a transistorized system, a solenoid valve associated with the oxygen supply means of the respiratory bag, which allows to modulate the oxygen concentration in the inspired mixture, directly in response to the instantaneous value of this concentration. However, these devices are delicate and expensive and present operating hazards which make it necessary to plan several, which again strikes the court.

 The subject of the present invention is a diving breathing apparatus which makes it possible to automatically maintain the partial pressure of the oxygen contained in the inspired mixture within safety limits, and this whatever the depth, this apparatus being free from the abovementioned drawbacks and having a simple and robust construction and an operation without hazard.

 According to the invention, a diving breathing apparatus, comprising a mask, inspiration and expiration ducts provided with non-return valves and connected both to the mask and to a respiratory bag whose volume varies with the rhythm of breathing. , oxygen and inert gas cylinders under pressure, each cylinder having a diaphragm valve calibrated by a spring, means for supplying oxygen and inert gas to the respiratory bag from said bottles and means for purging the bag respiratory, said supply and purge means being slaved to variations in the volumes of the respiratory bag, is characterized in that the pressure reducer of at least one of said bottles is associated with an additional membrane for correcting a predetermined section exposed to pressure surrounding and automatically modifying the calibration of the regulator spring in the direction which tends to decrease all the more the oxygen concentration in the mixture generally admitted in the respiratory bag, that the surrounding pressure is stronger.

 The section of the additional correction membrane is chosen with an optimum value taking into account the conditions of application of the device so as to comply with a suitable program of variation of the flow of oxygen and / or inert gas by the regulators in function from the depth.

 Thanks to this arrangement, the automatic adjustment of the partial pressure of the oxygen contained in the inspired mixture is carried out, not as a function of the instantaneous concentration of oxygen in the respiratory gas, but directly as a function of the surrounding pressure, that is to say depth. The regulator of at least one of the oxygen and inert gas cylinders thus has its calibration automatically corrected as a function of the pressure. surrounding.

 When the regulator with variable calibration is provided on the oxygen cylinder, the additional correction membrane resting on the surrounding pressure is arranged so as to relieve the stress of the calibration spring the more the greater the surrounding pressure, which has the effect of decreasing the supply rate of the respiratory bag with oxygen and consequently of maintaining the partial pressure of oxygen in the inspired mixture within suitable limits.

 When the variable rate regulator is provided on the inert gas supply bottle, for example nitrogen, the additional correction membrane exposed to the surrounding pressure is arranged so as to accentuate the force of the calibration spring as much the greater the depth, which has the effect of increasing the rate of supply of inert gas to the respiratory bag and therefore, here too, of keeping the partial pressure of oxygen in the inspired mixture within suitable limits.

 We. can advantageously provide a regulator with variable setting both on the oxygen cylinder and on the inert gas cylinder, which allows a fortiori to reduce the concentration. The greater the depth of oxygen in the inspired mixture, the greater the partial pressure of oxygen in the inspired mixture within safety limits.

 According to another characteristic, the means for supplying the respiratory bag include an oxygen intake valve and an inert gas intake valve which are mixed and subjected, on the one hand, to the ac 'a return spring in. closing and, on the other hand, to an opening command made active in response to each collapse of the respiratory bag. Preferably; the two twin valves have two neighboring annular seats connected respectively to the oxygen inlet and the inert gas inlet and a common shutter cooperating with the return spring when closing and with the opening control.

Forms of execution. of the invention are described below, by way of example, with reference to the accompanying drawings in which
Figure 1 is a schematic view of a diving breathing apparatus according to the invention and illustrates the operation at the end of the expiration period
Figure 2 is a view similar to Figure 1 but illustrates the operation at the end of the inspiration period
Figure 3 shows, on a larger scale, a variant of the oxygen and inert gas intake valves in the respiratory bag.

 Reference will first be made to FIGS. 1 and 2. A diving breathing apparatus, in particular for deep dives, is adapted to be worn independently by the diver and works in a semi-closed circuit.

 This device comprises (FIG. 1) a mask 10 and an exhalation duct 11 connected to the mask 10 and having a non-return valve 12 as well as an absorption cartridge 13 of carbon dioxide. The device also includes an inspiration duct 14 provided with a non-return valve 15. The ducts 11 and 14 are connected at 16 to a respiratory bag 17 whose volume varies with the rhythm of breathing.

 The apparatus also comprises a cylinder 18 of pressurized oxygen, with a regulator 19 and a bottle 20 of inert gas, for example nitrogen, under pressure, with a regulator 21.

 The regulator 19 or 21 comprises a valve 22 subjected to two antagonistic actions, that of a membrane 23 exposed to the low pressure of a chamber 24 defined by the membrane 23 downstream of the valve 22, and that due to the spring force 25.

 The chambers 24 of the regulators 19 and 21 are connected to the respiratory bag 17 respectively by conduits 26 and 27 provided with valves 28 and 29.

 The conduits 26 and 27 constitute means for supplying oxygen and inert gas to the respiratory bag 17 from the bottles 18 and 20. The valves 28 and 29 are provided subject to variations in the volume of the respiratory bag 17. For this purpose, the valves 28 and 29 are paired and subjected on the one hand to action. a closing return spring 34 and, on the other hand, an opening control 35 made active in response to each collapse of the respiratory bag. In the example shown, this opening command 35 comprises a plate 36 adapted to be pushed back by a movable wall 37 of the respiratory bag 17, each time this bag sags.

 The apparatus also includes purging means in the form of a transit chamber 38 whose volume varies with the rhythm of respiration and which is connected on the one hand, by a non-return valve 39 with the respiratory bag 17 and d on the other hand, by a non-return valve 40 with the outside.

 Whatever the depth, it should only pressure. partial oxygen in the melan.ge inspired by the conduit 14 remains within safety limits, and this for the safeguard of the diver.

 To this end, the regulators 19 and 21 of the bottles 18 and 20 are provided with a calibration corrected automatically as a function of the surrounding pressure.

 More particularly, the spring 25 of the regulator 19 is subjected to the action of an additional correction membrane 41 of suitable predetermined section exposed to the surrounding pressure and axially coupled to the membrane 23 by means of a rod 30 and the spring 25. The membrane 41 is associated with a return spring 42 and is arranged in such a way that, the greater the surrounding pressure and the more the membrane 41 tends to reduce the force of the spring 25, which has the effect of increase the closing of the valve 22, and consequently lower the pressure in the chamber 24.

 Similarly, the calibration spring 25 of the regulator 21 of the inert gas cylinder 20 is subjected to the action of an additional correction membrane 43, of suitable predetermined section exposed to the surrounding pressure. The membrane 43 is associated with a return spring 44 and is axially coupled by the rod 30 and the spring 25 to the membrane 23. The membrane 43 is arranged so as to further increase the force of the spring 25 as the pressure envirarte is stronger, which has the effect of accentuating the opening of the valve 22 and consequently of increasing the pressure of inert gas in the chamber 24.

 The sections of the additional correction membranes 41 and 43 are chosen with optimum values taking into account the conditions of application of the device, so as to comply with a suitable program of variation of the oxygen and inert gas flow rates by the regulators. 19 and 21 depending on the depth.

 During the expiration period (Figure 1), the air expelled through the exhalation duct 11, passes through the valve 12 as well as the carbon dioxide absorption cartridge 13 and enters at 16 into the respiratory bag 17 which inflates . The movable wall 37 of the respiratory bag 17 is spaced from the plate 36 for controlling the valves 28 and 29 and these are closed.

 While the bag 17 is inflating, the mixture of the bag passes through the valve 39 in the transit chamber 38 which, in the example shown, increases in volume at the same time as the bag 17, while the valve 40 is closed.

 during the inspiration period (Figure 2), the mixture is inspired by the conduit 14 via the valve 15 from the respiratory bag 17 by the connection 16. The bag 17 deflates. When the bag 17 is sufficiently collapsed, the movable wall 37 of the bag 17 pushes the plate 36 for controlling the opening of the valves 28 and 29 and these open, which allows an admission of oxygen and inert gas to from bottles 18 and 20. meanwhile, the transit chamber 38 decreases in volume. The valve 39 is closed and the excess gas mixture is discharged through the valve 40 which opens.

 Thanks to the automatic correction of the spring setting 25 of the regulators 19 and 21 of the bottles 18 and 20, depending on the surrounding pressure, that is to say the depth, the oxygen flow rate in the supply duct 26 is all the less the deeper the depth and, in the same way, the flow of inert gas in the duct 27 is all the stronger the deeper it is.

 In this way, the concentration of oxygen in the mixture generally admitted by the conduits 26 and 27 in the respiratory bag 17 is all the lower the higher the surrounding pressure, that is to say the depth,.

 As a result, the partial pressure of the oxygen in the mixture contained in the air inspired by the duct 14 is automatically maintained within safety limits, for example 1.5 bar and 0.2 bar, suitable for safeguarding the diver.

 We will appreciate the particularly simple and robust construction of the device according to the invention and also its hazard-free operation.

 It should be noted that the transit chamber 38, which empties and fills at the respiratory rate, could have variations in volumes opposite to those of the respiratory bag 17, instead of proportional as in the example shown and, in this case , this chamber 38 would be outside the bag, instead of being inside.

 As a variant (FIG. 3), we recognize at 26 and 27 the oxygen supply conduits and. inert gas from the respiratory bag.

 However, the twin valves 28 and 29 here comprise two neighboring annular seats 45 and 46 which are connected to the conduits 26 and 27 and a common shutter 47 which cooperates with the return spring 34 and with the opening control 35, which here consists of a bent lever 48 cooperating with the movable wall 37 of the respiratory bag.

 Such a construction allows very precise operation of the valves 28 and 29.

 It should be noted that one of the regulators 19 and 21 could be provided with an additional correction membrane 41, 43, instead of providing the two regulators with such membranes as in the example shown.

Claims (7)

 1) Diving breathing apparatus, comprising a mask, inspiration and exhalation ducts fitted with non-return valves and connected both to the mask and to a breathing bag whose volume varies with the rhythm of breathing, bottles of oxygen and inert gas under pressure, each bottle having a diaphragm valve calibrated by a spring, means.s for supplying oxygen and inert gas to the respiratory bag from said bottles and means for purging the bag respiratory, said supply and purge means being slaved to variations in the volume of the respiratory bag, respiratory device characterized in that the regulator of at least one of said bottles is associated with an additional membrane for correcting a predetermined section exposed to the surrounding pressure and automatically modifying the calibration of the regulator spring in the direction which tends to decrease all the more the oxygen concentration in the globally admitted mixture in the s respiratory ac, that the surrounding pressure is higher.  2) diving breathing apparatus according to claim 1, characterized in that the regulator of the oxygen cylinder and the regulator of the inertia gas bottle each have a calibration corrected according to the surrounding pressure.  3) Diving breathing apparatus according to claim 1 or claim 2, characterized in that the regulator diaphragm and the additional correction membrane are coupled axially via the calibration spring.  4) diving breathing apparatus according to any one of claims 1 to 3, characterized in that said supply means comprise an oxygen inlet valve gen.e and an intake valve. of inert gas in the respiratory bag, said valves being twinned and subjected on the one hand to the action of a closing return spring and, on the other hand, to an opening command made active in response each time the respiratory bag subsides.  5) diving breathing apparatus according to claim 4, characterized in that the two twin valves have two adjacent annular seats connected respectively to the oxygen inlet and the inlet. inert gas and a common shutter. cooperating with the closing return spring and with the opening control.  6) diving breathing apparatus according to any one of claims 1 to 5, characterized in that the purging means comprise a tran.sit chamber whose volume varies with the rhythm of breathing and which is connected by check valves back, on the one hand1 with the respiratory bag and on the other hand, with the outside.  7) diving breathing apparatus according to any one of claims 1 to 6, characterized in that the exhalation duct is provided with absorption means. carbon dioxide.