Classifications

• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62B—DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING
  • A62B17/00—Protective clothing affording protection against heat or harmful chemical agents or for use at high altitudes
  • A62B17/04—Hoods
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62B—DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING
  • A62B7/00—Respiratory apparatus
  • A62B7/02—Respiratory apparatus with compressed oxygen or air
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62B—DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING
  • A62B9/00—Component parts for respiratory or breathing apparatus
  • A62B9/02—Valves
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62B—DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING
  • A62B7/00—Respiratory apparatus
  • A62B7/14—Respiratory apparatus for high-altitude aircraft

Definitions

• the present invention relates to a respiratory protection equipment commonly called a hood.
• the invention relates more particularly to a respiratory protection hood comprising a flexible envelope intended to be threaded on the head of a user and a pressurized oxygen tank comprising an outlet opening opening into the internal volume of the flexible envelope, the outlet orifice being closed by a removable plug or breakage arranged.
• hoods must in particular allow the aircrew to fight the damage, rescue passengers and manage a possible evacuation of the aircraft.
• the device In order to meet the requirements of use, the device must be able to provide enough oxygen to the user.
• the hood may be designed to both prevent hypoxia at an altitude of 40000 feet two minutes after placement and then, in the final minutes of use, provide enough oxygen to allow evacuation.
• the known respiratory protection equipment mainly uses two types of oxygen source:
• a chemical bread also called “chemical candle” generating oxygen by combustion (potassium superoxide - KO 2 , sodium chlorate - NaClO 3 , etc.), or
• a compressed oxygen reservoir associated with a calibrated orifice.
• the first type provides an oxygen flow rate that grows to reach a relatively constant level before decreasing rapidly at the end of combustion.
• Properly sized chemical candle type generators can provide a source of oxygen to fulfill the desired conditions, but this solution has a major disadvantage: the combustion reaction of the candle is highly exothermic.
• the outer surface temperature of the device can easily exceed 200 ° C and ignite any combustible material in contact (a fatal accident has already occurred following the accidental activation of such a chemical candle in a container transport in the hold of an airplane).
• This type of device also has the disadvantage of requiring a certain time for the rise in flow of oxygen at startup. This may require the addition of additional oxygen capacity for startup. Finally, these devices require filters to remove impurities generated by the oxygen production reaction.
• the second type (pressurized oxygen tank associated with a calibrated orifice) provides a flow of oxygen that decreases exponentially, in proportion to the pressure inside the reservoir.
• the hoods using this second type generally contain a source of oxygen to supply a person with oxygen for 15 min.
• This equipment also has a means of limiting the pressure inside the hood (for example a pressure relief valve).
• This technology using compressed oxygen in a sealed capacity associated with a calibrated orifice is safer. Nevertheless, in order to be able to respond to certain use cases (significant consumption of oxygen at the end of use corresponding for example to an emergency evacuation of the apparatus), the capacity must have too much volume for the intended purpose.
• Another solution may be to provide a high initial pressure (greater than 250 bar). This generates a large initial flow, for example more than ten normoliter per minute (Nl / min) to have a sufficient flow at the end of use (for example more than 2NI / min at the fifteenth minute of use of the equipment ).
• the invention relates to a hood using an oxygen tank under pressure.
• An object of the present invention is to overcome all or part of the disadvantages of the prior art noted above.
• An object of the invention may notably be to propose a hood that can supply a relatively large quantity of oxygen at the beginning of use (to prevent hypoxia at high altitude) while allowing the supply of a sufficient quantity of oxygen. at the end of use (after ten or fifteen minutes) to allow evacuation.
• the hood according to the invention is essentially characterized in that the pressurized oxygen reservoir comprises, upstream of the orifice, a passage for the pressurized gas and a moving needle in a direction of displacement determined in said passage, the needle being subjected to two opposing forces in the direction of displacement and generated respectively on the one hand by the pressure of the gas in the reservoir and on the other hand, by a return member, the needle having a determined profile section variable in the direction of movement to change the degree of closure of the passage according to its position relative to the passage so as to regulate the flow of gas admitted to escape through the passage to the orifice as a function of time and gas pressure in the tank.
• embodiments of the invention may include one or more of the following features:
• the needle has a section of profile determined in the direction of displacement to control the flow of admitted gas to escape via the passage to the orifice according to a predetermined curve as a function of time and the initial gas pressure in the reservoir; ,
• the needle has a section of profile determined in the direction of displacement to control the flow of admitted gas to escape via the passage to the orifice as a function of time along a curve comprising a first phase delivering a first flow rate between 3NI; / min and 8NI / min when the pressure in the tank is between 250 bar and 100bar and a second phase delivering a second flow rate between 2 Nl / min and 5NI / min when the pressure in the tank is 100 bar and 30bar,
• the needle has a profile section determined according to the direction of movement, for controlling the flow of gas admitted to escape from the tank via the passage towards the orifice as a function of time according to a curve having substantially constant successive stages, that is, for a gas initially stored at an initial pressure of between 250 bar and 100 bar in the tank, the bearings have a flow reduction of less than 1 Nl / min, said bearings comprising a first flow rate between 3 and 6 NI (normoliter) per minute for a period of time between one and five minutes after the opening of the calibrated orifice, and a second flow rate of between 1, 6 and 3 NI per minute during a duration of between 5 and 25 minutes after the beginning of the opening of the calibrated orifice,
• the passage is formed in a partition delimiting an intermediate chamber between the calibrated orifice and the remainder of the internal volume of the reservoir, said intermediate chamber being put to the external pressure via the orifice calibrated during the opening of the closure plug ,
• the needle comprises a movable end in the intermediate chamber, the return member being housed in the intermediate chamber and exerting its force on this end,
• the needle has a section of increasing diameter
• the needle has a profile of increasing diameter and provided with at least one bearing of constant diameter
• the needle comprises a deformable waterproof capsule containing a gas at a predetermined pressure, in particular an altimetric capsule, said capsule being in abutment against at least one wall of the reservoir and deforming according to the pressure within the reservoir to cause a determined displacement of the needle in a direction of displacement as a function of the pressure in the reservoir,
• the flexible envelope is waterproof
• the oxygen reservoir is integral with the base of the flexible envelope, the oxygen reservoir has a generally tubular shape, in particular a C shape, to allow it to be placed around the neck of a user,
• the base of the flexible envelope forms a flexible diaphragm intended to be mounted around the neck of a user
• the hood comprises a device for absorbing CO2 which communicates with the inside of the envelope,
• the envelope comprises an opening through which the CO2 absorption device is arranged
• the capsule consists of at least one of: a steel, an alloy of copper or bronze,
• the needle is dimensioned so that pressure variations of 350bar in the tank cause displacement in translation of the needle in the direction by a distance of between 1 to 10 mm and preferably between 1 to 4 mm.
• the invention may also relate to any alternative device or method comprising any combination of the above or below features.
• FIG. 1 represents a front and schematic view illustrating an example of a hood according to the invention
• FIG. 2 is a sectional view of a detail of the hood of FIG. 1 illustrating a first embodiment of the pressurized oxygen tank
• FIGS. 3 and 4 show enlarged sectional views of a reservoir detail of FIG. 2 respectively according to two operating configurations
• FIG. 5 illustrates an example of oxygen flow curves that can be provided by a reservoir according to FIG. 2,
• FIG. 6 represents a sectional view of a detail of the hood of FIG. 1 illustrating a second embodiment of the pressurized oxygen tank, the two halves of the section respectively corresponding to two operating configurations,
• FIG. 7 to 9 show schematic and partial schematic views of three embodiments of a needle used in a reservoir according to the invention.
• the hood illustrated in Figure 1 typically comprises a flexible envelope 2 (preferably waterproof) to be threaded onto the head of a user.
• a transparent visor 13 is provided on the front face of the casing 2.
• the hood 1 also comprises a reservoir 3 of oxygen under pressure, arranged for example at the base of the casing 2.
• the base of the flexible envelope 2 may comprise or form a flexible diaphragm designed to be mounted around the neck of a user to ensure sealing.
• the hood 1 may comprise a CO2 absorption device (not shown) which communicates with the inside of the casing 2, to remove CO2 from the exhaled air by the user.
• the envelope 2 may comprise an opening through which the CO2 absorption device is disposed.
• another opening may be provided for a safety valve 14 provided to prevent overpressure in the casing 2.
• the oxygen tank 3 may have a generally tubular shape, in particular C-shaped, to allow its arrangement around the neck of a user.
• the reservoir 3 comprises an outlet orifice 4 opening into the internal volume of the flexible envelope 2, in order to deliver pure oxygen gas or an oxygen-enriched gas to the user.
• the reservoir 3 also comprises at least one filling orifice (not shown for the sake of simplification).
• the outlet orifice 4 is normally closed by a cap 5 removable or breakage arranged and will be open only when used.
• the orifice 4 communicates the outside with the internal volume of the reservoir 3.
• the tank 3 of oxygen under pressure comprises, upstream of the plug 5, a passage 6 for the gas under pressure and a needle 7 movable in a direction A of displacement determined in said passage 6
• the needle 7 is movable in translation in the direction A of displacement.
• the passage 6 may be formed in a partition 16 delimiting an intermediate chamber 31 between the outlet orifice 4 and the remainder of the interior volume of the reservoir 3.
• This separating partition 16 may be integral with a housing inserted at one end of the reservoir 3. This housing can integrate the plug 5 frangible.
• the volume of the intermediate chamber 31 corresponds for example to a io th to 50 th of the total volume of the reservoir 3.
• the needle 7 can cooperate with a seal 9 arranged at the passage 6.
• the needle 7 is subjected to two opposing displacement forces in the direction A and generated respectively on the one hand by the pressure of the gas in the tank 3 and, on the other hand, by a return member 8.
• the gas pressure in the tank 3 pushes the needle 7 towards the outlet port 4 while the return member 8 (for example a compression spring) pushes the needle 7 in the opposite direction.
• the return member 8 for example a compression spring
• the 7 may thus comprise an end 17 movable in the intermediate chamber 31 on which the spring 8 exerts its force.
• the needle 7 has a profile section 10 determined variable along the direction A of displacement to change the degree of closure of the passage according to its position relative to the passage 6.
• This profile 10 which may comprise longitudinal grooves in the direction of movement A, is configured to regulate the flow of admitted gas to escape via the passage 6 to the open outlet port 4 when the plug 5 is removed.
• the needle 7 has a profile section determined in the direction A of displacement to control the flow of gas admitted to escape via the passage 6 to the orifice 4 calibrated according to a predetermined curve as a function of time and the initial pressure in the tank 3.
• NI normolitre
• the reservoir 3 contains gas under pressure including in the intermediate chamber 31 (see Figure 3).
• the orifice 4 fluidly connects the intermediate chamber 31 with the outside.
• the intermediate chamber 31 and thus the spring 8 are then found at the external pressure. Gas escapes at a rate controlled by the passage formed between the profile 10 of the needle 7 and the edge of the passage 6.
• the needle 7 is displaced by the pressure in the reservoir (this force takes over the spring force 8 which is compressed, see Figure 4).
• the spring 8 moves the needle 7 again against the gas pressure (to the left in FIG. 4).
• the released flow rate can follow various predetermined changes.
• This first curve is obtained via a needle 7 having a profiled section determined in the direction A of displacement.
• This curve provides successive successive stages substantially constant, that is to say that, for a gas initially stored at an initial pressure determined in the tank 3, the flow admitted to escape through the outlet orifice 4 is first substantially constant around a first determined value (for example 3.2 NI per minute for about 6 minutes). Then this flow then decreases to reach a second substantially constant level at a determined value around 2NI / minute (for about 25 minutes).
• FIG. 5 represents in continuous line another more theoretical flow curve that can be approximated by a device according to the invention.
• This curve comprises a first short step (approximately 1 to 2 minutes) at a relatively high flow rate (approximately 5.2 NI per minute for example) and then a decrease in flow rate to a second level (for example at approximately 1.8 Nm). per minute for about 35 minutes) before decreasing.
• a first short step approximately 1 to 2 minutes
• a relatively high flow rate approximately 5.2 NI per minute for example
• a second level for example at approximately 1.8 Nm. per minute for about 35 minutes
• the needle 7 may comprise a deformable waterproof capsule 27 containing a gas at a determined pressure, in particular an altimetric capsule.
• the altimetric capsule 27 (also called anemometric capsule) may be made of stainless steel, steel or any other suitable material.
• This capsule 27 constitutes a sealed volume containing a gas at constant pressure (generally at a pressure included near vacuum, for example between 0.1 bar and 1 bar) throughout its lifetime.
• the gas contained in the capsule 27 is for example air.
• the change in volume of the capsule 27 moves the needle 7 relative to the body of the tank 1 and varies the distance between the needle 7 and the passage 6 in the direction A of displacement.
• the flow is thus modified by the modification of the open section at the level of the passage.
• Such mechanisms are used in pneumatic-mechanical oxygen regulators to provide the altimetric overpressure function. They are also used in the automobile to reduce the intake during braking phases.
• Figure 7 schematically illustrates a needle 7 whose section is variable and has several bearings 77 of different constant diameter. Such Profile allows to obtain variations of sections at the level of the passage between three constant passage sections.
• Figure 8 illustrates a needle profile 7 having a section of increasing diameter linearly. This can make it possible to obtain a variable passage section according to the position with respect to the passage 6.
• Figure 9 illustrates a needle profile 7 comprising a diameter increasing to a constant diameter bearing. Such a profile makes it possible to obtain a variable passage section as a function of the position in the direction of displacement A and then a constant passage section.
• FIGS. 2 and 6 may comprise a single filling orifice (preferably distinct and opposite to the calibrated outlet orifice 4).
• the movable needle 7 does not require a large stroke in the direction A of displacement, a few millimeters (1 to 4 mm for example) may be sufficient to control flow rates over a period of 15 to 30 minutes for example for all classes ( 1 to 4) uses of the hood 1.

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• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Business, Economics & Management (AREA)
• Emergency Management (AREA)
• Pulmonology (AREA)
• Emergency Medicine (AREA)
• Toxicology (AREA)
• Respiratory Apparatuses And Protective Means (AREA)
• Filling Or Discharging Of Gas Storage Vessels (AREA)
• Infusion, Injection, And Reservoir Apparatuses (AREA)
• Silicates, Zeolites, And Molecular Sieves (AREA)
• Laminated Bodies (AREA)

Applications Claiming Priority (2)

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• 2013
  • 2013-06-12 FR FR1355432A patent/FR3006900B1/fr not_active Expired - Fee Related
• 2014
  • 2014-05-02 JP JP2016518556A patent/JP6612218B2/ja active Active
  • 2014-05-02 CN CN201480032374.XA patent/CN105263586B/zh active Active
  • 2014-05-02 CA CA2912326A patent/CA2912326C/fr active Active
  • 2014-05-02 WO PCT/FR2014/051047 patent/WO2014199028A1/fr active Application Filing
  • 2014-05-02 EP EP14727879.0A patent/EP3007775B1/de active Active
  • 2014-05-02 RU RU2016100183A patent/RU2655237C2/ru active
  • 2014-05-02 US US14/897,081 patent/US10335617B2/en active Active

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