Respirator and installation of protection against hypoxia including application

CA 02393078 2002-07-10 1 RESPIRATORY APPARATUS AND INSTALLATION FOR PROTECTION AGAINST HYPOXIA INCLUDING APPLICATIONS The present invention relates to breathing apparatus intended to protect crew members, and in particular the technical flight personnel, of an airplane against the risks associated with depressurization at high altitude and / or the appearance of fumes.

It finds a particularly important, although not exclusive, application on apparatuses for transporting passengers which can reach high altitudes and above all on so-called “jumbo” or “super jumbo” apparatus of very large capacity.

Each pilot of a current passenger transport aircraft has a breathing apparatus comprising a mask fitted with a regulator connected to a source of breathing gas.

Aviation regulations require that this mask can be put on and deliver oxygen to the wearer in less than 5 seconds.

This result is generally achieved at the present time by using an inflatable and deflatable pneumatic harness mask, such as one of those described in documents FR 1 506 342 and 2 784 900 and EP -A-0 628 325 and the documents. U.S. Patents 5,503,147, 5,590,102 and 5,623,923.

The source of pressurized gas must be permanently capable of supplying, instantaneously, oxygen or air highly enriched in oxygen under sufficient pressure to inflate the harness and supply the mask regulator.

This source is usually a pressurized oxygen cylinder.

CA 02393078 2002-07-10 2 On passenger transport airplanes, another installation makes it possible to supply passengers, in the event of depressurization, with respiratory gas allowing survival until the airplane has descended to a altitude allowing normal breathing at ambient atmospheric pressure.

s On the "jumbos" the reserve of oxygen thus required represents a very large mass.

To reduce this mass, the oxygen reserve can be replaced by an on-board oxygen generator, such as a battery of generators by selective absorption and release of oxygen, called OBOGS (on-board oxygen generator to systems) which use the air coming from the compressor of one or more engines.

However, such generators only supply air very enriched in oxygen with a delay from their release command.

In addition, their outlet pressure depends on the speed of the feed motor and the degree of enrichment of the air supplied is also variable.

The pressure initially available may be insufficient to allow inflation of the rapid installation harness.

The initial degree of enrichment may also be insufficient.

A common buffer tank intended to serve as a reserve of very enriched air, placed at the outlet of the OBOGS and kept folded; provides only an imperfect solution, in particular because the available pressure may be insufficient to inflate the harness and the presence of a pipe introduces a delay. Other types of on-board generators or even oxygen reserves have similar drawbacks.

The present invention aims in particular to provide a breathing apparatus of the type CA 02393078 2002-07-10 3 having an inflatable pneumatic harness mask which meets the requirements of practice better than those previously known, in particular on large-capacity transport devices; it is particularly aimed at ensuring that breathing gas at a sufficient pressure to allow rapid installation and to guarantee that a sufficient oxygen content of the inspired gas will be available from the user's first breaths, and this before the he plane has reached the altitude at which this availability is essential, or even before take-off.

For this purpose the invention provides in particular a breathing apparatus comprising, on a supply line of the mask regulator, a buffer capacity specific to the ~ o mask, of sufficient volume to ensure at least two successive typical inspirations, provided with an admission equipped with a non-return valve and intended to be connected to an oxygen-enriched air generator.

Thus the pressure which is established in the capacity is the maximum pressure supplied by the generator during the preceding period.

In the case, which is that of an OBOGS, where the oxygen content is variable, is in particular according to the moment of the restitution cycle, it is preferable to provide the inlet line with a valve not allowing the initial filling. of the capacity only when the oxygen content is greater than a determined threshold, for example 94%.

This valve can also be kept closed when the inlet pressure is insufficient.

2o Means will generally be provided for, once the first inspirations have passed and the generator in steady state, or in the event of exhaustion of the capacity when the generator does not yet fully meet the above conditions, CA 02393078 2002-07-10 4 allow gas from the generator to pass through the mask regulator.

In practice a capacity of 3 to 5 liters of expanded gas will be sufficient.

Inflating the harness of current masks generally requires a pressure of about 2 bars and a volume of the order of 1 liter.

Usually an OBOGS provides a pressure which can vary in a ratio of 1 to 6 depending on the engine speed.

In the case of an OBOGS supplying a variable pressure of 0.5 to 3 bars, the maximum pressure, reached when the motors are at full power for the climb, greatly exceeds the value required in the capacity.

The invention makes it possible to use a common on-board generator for the crew and the passengers and to avoid the carrying of heavy oxygen cylinders and to be checked frequently, other than those required for possible therapeutic needs.

The capacitor can often be incorporated into the mask box, the opening of which triggers the supply of oxygen; it is then directly connected to the supply hose of the regulator and the mask harness.

This adaptation simply involves a limited increase in the size of a box such as that described for example in document US Pat. No. 6,039,045.

The above characteristics, as well as others, will appear better on reading the following description of particular embodiments, given by way of non-limiting examples.

The description refers to the accompanying drawings, 2o in which FIG. 1 is a simplified view of an apparatus constituting a particular embodiment of the invention, with a so-called full or "full face" mask;

then shown CA 02393078 2002-07-10 s that the mask is out of the box;

- Figure 2 shows an alternative embodiment.

The apparatus shown in FIG. 1 comprises a respiratory mask 10 with a regulator 12 allowing dilution with ambient air, provided with a pneumatic harness 14 which may in particular be of any one of the types described in the patent applications already. mentioned.

Outside the periods of use, the mask and the harness are stored in a box 16 provided with a door with two flaps 18 and 20.

A valve 22 carried by the housing of the box is interposed between a hose 26 connected to the regulator of the mask and a supply line 24.

The valve 22 is positioned so that it puts the flexible hose and the pipe 24 in communication when the user of the mask 10 pulls the latter out of the box and the flap 18 opens.

Sometimes the box also has a switch allowing the choice between operating the regulator with dilution (protection against hypoxia only) and without dilution (protection against fumes).

is Line 24 is intended to receive air very enriched in oxygen coming from a generator 30, generally constituted by a battery of OBOGS with absorption and return-shifted cycles.

Two OBOGS are shown in Figure 1.

The same generator supplies a large number of masks. It may for example be at. molecular sieve. Such generators exist on the market, for example using the arrangements described in US Pat. No. 4,561,865 and the prior art cited therein.

In the embodiment of the invention shown in FIG. 1, a supply line CA 02393078 2002-07-10 6 ensuring the connection between the box and an outlet manifold 32 of the generator 30 comprises successively, downstream upstream , a capacity 34, a non-return valve 36 and a solenoid valve 38.

The non-return valve ensures that a volume of air very enriched with oxygen and at a sufficient pressure to inflate the harness is maintained even during periods when the generator 30 supplies air at a pressure lower than that which reign in capacity 34. The three-way solenoid valve 38 is associated with a control module which allows the supply of the capacity only when the gas coming from the generator 30 has an oxygen content above a threshold, for example 94 t 2% as long as the mask is stored.

For this, a gas analyzer 42 is placed on the supply line of the capacitor 34 and supplies a signal to the module 40.

This module 40 may also include a pressure tap 44 and a hearth provided so as to place the manifold 32 and the capacity 34 in communication only when the pressure supplied by the generator exceeds a determined value, greater than the value necessary to fully inflate the harness 14. .

is In a simplified embodiment, the solenoid valve 38 is controlled to put the manifold 32 and the non-return valve 36 in communication as long as the oxygen content of the respiratory gas exceeds the threshold. when the source of oxygen enriched gas initially provides a high oxygen content, the solenoid valve 38 may be omitted.

In another variant, the module 40 is provided to control the solenoid valve and put the manifold 32 and the non-return valve 36 in communication when it receives a CA 02393078 2002-07-10 7 signal to open the shutter 18 of the valve. the box: thus, the mask is always powered when it is worn.

In the alternative embodiment shown in FIG. 2, the mask 10 is intended to be stored other than in a mask box. 11 is connected by the flexible pipe 26 s to a separate capacity.

The connection between the capacity 34 and a solenoid valve 38 includes a non-return valve 36.

In the illustrated case, the solenoid valve 38 is connected to a control module 40 which places the manifold 32 in communication with the non-return valve 36 - when the oxygen content, measured by a gas analyzer 42, exceeds a determined value, and - when the pressure in the capacity 34, measured by a sensor 44, is less than a determined value, in order to guarantee the availability of respiratory gas coming from the source.

Still other embodiments are possible, whether or not using the solenoid valves, in particular depending on the nature of the generator 30.

The method of implementing the installation may for example be the following erg case of employment of .generators-OBOGS. _ _ From the initial climb phase of the aircraft after takeoff, at least one of the generators 30 is put into service to selectively draw oxygen.

The 2o reactors then being at full power, the air passing through the molecular sieve of the generator is at high pressure.

Once the molecular sieve is saturated, the air supply is transferred to another OBOGS.

A set of valves provided on the first OBOGS CA 02393078 2002-07-10 ô is ordered to put it in connection with the pipe 32 and the OBOGS is heated to restore oxygen.

Since the pressure is high and the gas has a high oxygen content, the buffer tanks 34 fill up to a pressure sufficient to inflate harnesses.

Means may be provided to purge the buffer capacity s of the air which it may contain before filling with enriched air under pressure.

One or more common reservoirs 46 can also be filled at this stage.

Once these operations have been carried out and the second OBOGS also saturated with oxygen, the first can also be recharged in order to have a maximum reserve.

In a variant, one at the hands of the generators is controlled according to an absorption-restitution cycle before take-off so that the pilots have gas rich in oxygen and under pressure making it possible to put on the masks, in the event of smoke for example.

In all cases, pilots will be able to put on the respiratory mask in a few seconds regardless of the altitude and immediately have very enriched respiratory gas available for 1 s.

The common tank or tanks will allow the passengers to also have oxygen with a delay which can be a little more -important #. - Due to the fact that the generators are initially saturated with oxygen and under pressure, they will make it possible to maintain a high pressure supply for the time necessary to descend to the end of cruise altitude, between 5000 and 8000 meters, at which a pressure which will be lower (because the engine speed is reduced) is sufficient for the respiratory needs.