Classifications

• • 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 generally to demand and dilution regulators by ambient air intended to supply respiratory gas to meet the needs of a wearer equipped with a mask, using a supply by an oxygen source.
• It relates in particular to the regulation methods and devices intended for respiratory apparatus intended for the crews of civil or military aircraft which, beyond a determined cabin altitude, must receive respiratory gas representing at least a minimum flow of oxygen which is depending on the altitude, or, with each inhalation, an amount of oxygen corresponding to a minimum oxygen content of the inhaled mixture.
• the minimum oxygen flow law is set by standards, which are currently the subject, for the civil sector, of a FAR regulation.
• regulators on demand can be worn by the mask; this is the most frequent case in the civil field, unlike the case of combat aircraft, where the regulator is often in the seat of the carrier.
• These regulators have an oxygen supply circuit connecting a pressurized oxygen inlet to an intake in the mask and comprising a main valve, generally pneumatically controlled by a pilot valve, and a dilution air supply circuit. from the ambient atmosphere.
• the opening and closing of the oxygen supply takes place in response to the inspiration and expiration of the wearer of the mask, to the cabin altitude and possibly to the position of selection means, actuable manually, allowing normal operation with dilution, operation with supply without dilution, and operation with overpressure.
• Regulators of this type are described in particular in document FR-A-2 778 575, to which reference may be made.
• a regulator with electronic control for supplying the respiratory mask for a combat aircraft pilot has also been proposed (patents FR 79 11 072 and US - A - 4 336 590.
• This regulator uses pressure sensors and control electronics. of a solenoid valve for regulating the flow of oxygen supplied. The dilution air is sucked in by a venturi.
• This electronically controlled regulator has the advantage of allowing a better adaptation of the flow of pure oxygen supplied to physiological requirements. it has a certain number of limitations. In particular, the dilution depends on the functioning of an ejector.
• the nature of the control of the flow of pure oxygen and of the flow of dilution air means that the oxygen supplied by the air of dilution, the flow rate of which is a function of the oxygen flow rate and other state parameters (in particular the inspiratory demand of the wearer) can hardly be taken into account in the control of pure oxygen flow rate.
• the control will cause a flow of pure oxygen leading to an excess of oxygen supplied to the carrier and it is not planned to use the electronic control so as to obtain an operation making it possible to provide a flow of oxygen which is in all conditions as close as possible to the minimum provided for by the regulations.
• the present invention aims in particular to provide a method and a regulation device which respond better than those previously known to the requirements of practice; it aims in particular to provide a regulator making it possible to bring the required oxygen flow rate closer to the source than that which is actually necessary.
• the instantaneous inhaled volume inspiratory flow rate brought back to ambient conditions is measured in real time (directly or from the measurement of the dilution air flow rate inhaled in the mask, taking into account the additional oxygen), and the ambient pressure ,
• the minimum oxygen content to be achieved over the entire inhalation is determined to comply with the respiratory standard, and - the instantaneous flow of additional pure oxygen is estimated and controlled so as to fulfill the requirements of the standard with a safety margin which will generally be a few percent.
• a regulation of the dilution air can be provided by adjusting the passage section using an altimetric capsule, without the intervention of a venturi; it can also be performed by a pilot valve, again without an ejector, then combining the favorable characteristics of the regulators purely pneumatic to those of a known regulator with electronic control.
• the estimation of the additional oxygen flow rate continues throughout the inhalation period. This effectively translates into adjustment of the entire volume of additional oxygen supplied during the entire complete inhalation.
• account is taken of the fact that the respiratory tract has a volume which does not participate in gas exchanges. More precisely, the fraction of the respiratory mixture which is inhaled last does not reach the pulmonary alveoli. It simply enters the upper airway from where it is released to the atmosphere upon expiration.
• the method according to the other embodiment uses this observation, for example by detecting the instant from which the instant inhaled flow rate drops below a predetermined threshold as indicating the start of the final phase of inhalation, during from which oxygen is not used, and then cutting off the supply of additional oxygen
• a comparison is made during the next phase of the inspiratory cycle between the standard cycle thus evaluated and the course of the actual cycle; in the event of a deviation leading to an oxygen requirement greater than that expected, a quantity of additional oxygen determined according to the deviation is provided.
• the amount of oxygen necessary for physiological needs, calculation of the amount of pure oxygen to be forcedly added to the oxygen contained in the air at a content 21% (or higher in the case of a conditioned atmosphere) inhaled directly from the ambient atmosphere and the flow rate of which is generally not controlled.
• the invention also provides a regulation device comprising:
• a dilution circuit bringing air from the atmosphere directly to the mask, which can be fitted with an opening valve controlled by ambient pressure,
• an expiration circuit comprising an expiration check valve connecting the mask to the atmosphere
• the air flow sensor can have various constitutions. For example, it is of the depression type, commercially available. Such a sensor determines the pressure drop when passing a throttle and provides a signal representative of the flow. It can also be of the hot wire type.
• Such a constitution is “hybrid” in the sense that it combines the characteristics of a pneumatically controlled regulator as regards the air flow rate with an electronic control of the flow rate of additional pure oxygen, allowing flexible regulation.
• oxygen under pressure or "pure oxygen” should be interpreted as covering both the case of pure oxygen, supplied for example by a bottle, and that of air very enriched in oxygen, typically above 90% . In the latter case the effective oxygen content of the enriched air constitutes an additional parameter to be taken into account and it must be measured.
• the flow control valve can be progressive opening, or of the "all or nothing" type; in the latter case, it is controlled by an electrical signal modulated in pulse width, with an adjustable duty ratio and a pulse frequency greater than 10 Hz.
• the control law stored in the electronic circuit is such that the regulator provides, in "normal” operation, a total oxygen flow rate at least equal to that provided for by the regulations for each cabin altitude, originating from the source and the dilution air.
• the regulators are provided to allow not only normal operation with dilution, but also operation with supply of pure pure oxygen (so-called "100%” operation), or of pure oxygen having a determined overpressure relative to the atmosphere. ambient (“emergency" operation). These latter operating modes are particularly necessary when the risk of the presence of smoke or toxic gas in the environment is taken into account.
• the electronic circuit may be provided to cause the dilution valve to close in response to a manual or automatic command.
• An additional solenoid valve with manual and / or automatic control may be provided to maintain an overpressure in the mask by establishing an overpressure tending to close it on the exhalation valve.
• the closing of the dilution valve is advantageously controlled by means of a two-position solenoid valve which, in a state, causes the closing of the valve by bringing the valve seat against a shutter carried by a pressure-sensitive element. of the ambient atmosphere and, in the other position, brings a valve seat in a determined position, allowing the adjustment of the dilution air flow by displacement or deformation of the element.
• the invention is susceptible of numerous embodiments.
• the different components of the regulator can be distributed different ways between a box carried by the mask and a box for storing the mask outside of periods of use or any other external box, including online, so that it remains directly accessible by the wearer of the mask.
• the pure oxygen supply circuit can be entirely placed in a box fixed to a mask, or
• this circuit and in particular the first solenoid valve, can be integrated into a mask storage box in the standby position.
• FIG. 1 is a pneumatic and electrical diagram showing the constituents concerned by the invention of a regulator which can be described as "with integrated actuator";
• FIG. 3 is a diagram showing a typical curve of variation of the oxygen flow required by the regulations as a function of the cabin altitude; - Figure 4 shows a bundle of variation curves of the oxygen flow rates of the inspiratory call at different cabin altitudes.
• the regulator shown in Figure 1 consists of two parts, one 10 incorporated in a housing carried by a mask not shown and the other 12 carried by a mask storage box.
• This box can have a conventional general constitution, comprising a frame delimiting a reception volume, closed by doors and from which the mask projects. The opening of the doors by extraction of the mask causes the opening of an oxygen supply valve.
• the part carried by the mask consists of a housing made up of several assembled parts, in which are housed and passages making it possible to define several circulation paths.
• a first circulation path connects an inlet 14 of oxygen under pressure to an outlet 16 towards the mask.
• a second path connects an inlet 20 for dilution air to an outlet 22 towards the mask.
• the oxygen flow in the first path is regulated by an electrically controlled valve.
• this tap is a proportional valve 24, voltage-controlled, which connects the inlet 14 and the outlet 16, supplied by a conductor 26, it connects the inlet and the outlet. It is also possible to use a valve, of the "all or nothing" type, controlled in pulse width, with a variable RCO (duty cycle).
• This sub-assembly On the path for direct supply of dilution air to the mask, there is a sub-assembly which can be described as a "demand" ensuring the functions of ambient air inspiration and detection of the instantaneous requested flow rate.
• This sub-assembly includes a pressure sensor 28 in the mask.
• the straight section of passage of the dilution air flow is delimited by an altimetric capsule 30 whose length increases when the ambient pressure decreases and by the end section of an annular piston 32.
• This piston is subjected to the difference between atmospheric pressure and the pressure prevailing in a chamber 34.
• An additional solenoid valve 36 makes it possible to connect the chamber 34 either to the atmosphere or to the supply of oxygen under pressure.
• the solenoid valve 36 thus makes it possible to pass from a normal mode with dilution to a mode with pure oxygen supply (so-called 100% mode).
• a spring 38 maintains the piston in a position allowing the adjustment of the passage section by the altimetric capsule 30.
• the piston is applied against the capsule.
• the piston 32 can also constitute the movable member of a controlled regulation valve.
• the housing of part 10 also delimits an expiration path comprising an exhalation valve 40.
• the shutter element of the valve shown is of a type commonly used at present for fulfilling the dual function of pilot valve d intake and exhaust valve. In the embodiment of Figure 1, it simply acts as a valve expiration offering the possibility of maintaining the interior of the mask in overpressure relative to the ambient atmosphere by increasing the pressure prevailing in a chamber 42, limited by the element 40, above the ambient pressure.
• a solenoid valve 48 connects the chamber 42 to the atmosphere and in this case the expiration takes place as soon as the pressure in the mask exceeds the ambient pressure.
• the solenoid valve 48 connects the chamber to the pressurized oxygen supply, by means of a throttling valve 50 for limiting the flow rate.
• the pressure in the chamber 42 is established at the value fixed by a valve 46 with calibrated closing spring.
• the housing of part 10 carries, in the illustrated embodiment, means making it possible to inflate and deflate a pneumatic mask harness.
• These means have a conventional constitution and therefore will not be described in detail. They comprise a piston 52 which can be brought temporarily, by means of an ear 54 actuated by the user of the mask, from the position where it is represented and where it makes the harness communicate with the atmosphere to a position where it communicates the harness with the oxygen supply 14.
• these means further comprise a switch 56 controlled by the movement of the ear 54 from its rest position, and whose role will appear later.
• Part 12 of the regulator which is carried by the mask storage box, includes a selector 58 which can be moved in the direction of the arrows "f" and which can be brought by the user into 3 positions.
• the selector 58 closes a switch 60 of normal mode N. In the other two positions, it closes respectively so-called 100% and "Emergency" or E mode switches.
• the switches are connected to an electronic circuit 62 which determines, depending on the operating mode chosen, the cabin altitude indicated by a sensor 64 and the instantaneous demand flow indicated by the sensor 28, the oxygen flow rate to be supplied to the wearer of the mask.
• the card provides the appropriate electrical signals to the first solenoid valve 24.
• the pressure sensor 28 supplies the instantaneous demand pressure at the outlet of the dilution air circuit in the mask.
• the circuit carries by an electronic card, receives this signal as well as the information on the cabin altitude to be taken into account coming from the sensor 64.
• the electronic card determines the flow rate or the quantity of oxygen to be supplied, using a family of stored reference curves taking into account the instantaneous demand flow and cabin altitude, or a table with several inputs or even a calculation in real time from a stored algorithm.
• the reference curves are established from the regulations which fix the concentration of respiratory mixture required for the pilot as a function of the cabin altitude.
• the curve in solid lines shows the minimum value of the oxygen content required as a function of the altitude.
• the dashed curve gives the maximum value.
• the reference curves will be chosen so that they are never below the minimum curve. But, thanks to the flexibility offered by electronic control, it will be possible to be very close to it.
• FIG. 4 shows, by way of example, two curves representing respectively the variation in the oxygen flow rate and the dilution air flow rate controlled by the solenoid valve 24 and the opening valve controlled as a function of the altitude, at given value of the signal supplied by the sensor 28.
• the card 62 sends an electrical instruction to the solenoid valve 36.
• This causes the chamber 34 to be pressurized, applies the piston 32 against the altimetric capsule 30 and closes the arrival of dilution air.
• the pressure sensor 28 detects the vacuum in the ambient air inlet circuit and supplies the card 62 with corresponding information.
• the card determines the speed oxygen to supply.
• the first solenoid valve 24 then supplies the wearer of the mask with the calculated amount of oxygen.
• the card 62 When the wearer selects the "emergency" mode by moving the selector 28 further to the right, the card 62 sends an electrical instruction to the valve 48.
• the solenoid valve then admits, in the chamber 42, a pressure which is limited by the valve 46.
• the overpressure established is of the order of 5 mbar.
• the dilution air supply is cut off as in the previous case.
• the pressure sensor 28 also sends a signal to the card 62 which determines the quantity of oxygen to be supplied to reduce the pressure in the air inlet circuit to a value equal to the setting of the valve 46.
• the first valve 24a is placed in the case of the mask storage box.
• the regulator can then be viewed as comprising a control part, entirely carried by the box 12 and which authorizes the selection of the operating mode.
• a "demand” part placed in the box mounted on the mask and which performs the functions of ambient air inspiration and detection of the call pressure.
• the third part which provides the supplement of oxygen required according to the altitude and the pilot's inspiratory demand, is this time in the case of the mask storage box.
• the control of supply of the additional oxygen by the valve 24 a is completed by a pneumatic pilot valve 68 of known constitution, placed downstream of the valve 24 a.
• the piloted pneumatic valve 68 is controlled by the pressure prevailing in a pilot chamber 70.
• the membrane 40 which this time plays the dual role of pilot valve and exhalation valve, controls the pressure in the chamber 70.
• the presence of the pilot valve in the embodiment of FIG. 2 makes it possible to provide a mechanically controlled valve 72 controlled by the selector 58 for connecting upstream to downstream of the solenoid valve 24 (a).
• the wearer of the mask can immediately switch from a regulated oxygen-saving mode to a conventional mode with purely pneumatic operation.

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• Health & Medical Sciences (AREA)
• Pulmonology (AREA)
• General Health & Medical Sciences (AREA)
• Business, Economics & Management (AREA)
• Emergency Management (AREA)
• Respiratory Apparatuses And Protective Means (AREA)

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• 2001
  • 2001-11-08 FR FR0114452A patent/FR2831825B1/fr not_active Expired - Lifetime
• 2002
  • 2002-09-27 US US10/256,943 patent/US6789539B2/en not_active Expired - Lifetime
  • 2002-10-29 CA CA002460462A patent/CA2460462C/fr not_active Expired - Lifetime
  • 2002-10-29 DE DE60205033T patent/DE60205033T2/de not_active Expired - Lifetime
  • 2002-10-29 EP EP02793196A patent/EP1441812B1/de not_active Expired - Lifetime
  • 2002-10-29 EP EP05014132A patent/EP1579890A1/de not_active Withdrawn
  • 2002-10-29 WO PCT/FR2002/003712 patent/WO2003039679A1/fr not_active Application Discontinuation

Non-Patent Citations (1)

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