SE1930029A1 - Dispensing regulator unit and breathing aid system - Google Patents

Abstract

A breathing aid system (200) and a dispensing regulator unit (205, 206, 211) for dispensing liquid, gaseous or dry powder inhalant in order to prevent or relieve problems, such as asthma, other breathing difficulties or dehydration, into a breathing system for a pressurized environment is disclosed. The dispensing regulator unit comprises a housing (205) defining a dispensing chamber (207) for the substance and a coupling interface for connecting the housing to the breathing system. A dispensing channel (209) connects the dispensing chamber (207) to a breathing gas flow (204) and a demand valve (211) maneuverable for permitting flow communication between the dispensing chamber (207) and the breathing gas flow (204) upon demand by a user.

Description

Dispensing regulator unit and breathing aid systemTECHNICAL FIELD The present invention relates to a regulator unit and a system for on-demand dispensing of a liquid, gaseous or dry powder inhalant into a breathing system.

BACKGROUND AND PRIOR ART The present invention relates particularly to a dispensing regulator unit arranged fordispensing an inhalable substance of medical effect into breathing gas supplied from a breathing system, such as a breathing apparatus for underwater activities. ln this connection, the term “breathing system” comprises the necessary components such aspressure containers, hoses, regulators and mouthpieces, which are typically included in an open-circuit (Fig. i) or closed-circuit deznand valve-controlled breathing apparatus.

The term “breathing aid system” on the other hand refers to a breathing system which is modified for adding an inhalable substance to the breathing gas.

Without limiting the scope of the invention hereto, the “inhalable substance” referred to mayinclude any therapeutic fluid, gaseous or dry powder system that provides a medicinal effecton, e.g., asthma, bronchitis, COPD or other lung conditions. The inhalable substance maycontain a fluid e.g. water to be dispensed into the breathing gas as prevention against dehydration.

As used herein, the term “pressurized environment” refers to an environment which holds apressure that is different from the atmospheric pressure in air at sea level. Further in thisdisclosure, the term “breathing gas” includes oxygen and/or mixtures of oxygen with other gaswhich may be added in order to prevent decompression sickness or oxygen toxicity, e.g.Another term of frequent use in this presentation is the word “p|unger”, which can beunderstood as a moveable object at least partially powered and driven by, or against, a fluid or gas pressure.

Although described herein essentially in connection with diving in water, embodiments of the invention can be implemented in breathing systems for other pressurized environments such as in submerged vessels, in smoke filled buildings or at high altitudes, and the invention shall not be restricted to diving.

However, diving in waters entails particular difficulties for persons with a breathing problemsuch as asthma, bronchitis or obstructive lung disease. ln practice, persons with any kind ofmedical lung condition have hitherto been prevented from use of breathing systems required for sea diving, such as the SCUBA or the Aqua Lung breathing systems, e.g.

Medical drugs, such as bronchodilators or corticosteroids, are generally administered in theform of a micronized dry powder or as a mist or aerosol wherein the medication is dissolved orsuspended in a gas propellant. The medicine is typically dispensed from a container via amouthpiece that is put in the mouth of the user which inhales a released dose of the medicinetogether with inhaled air. Among these commonly used devices are nebulizers, dry powderinhalers (DPI), metered dose inhalers (MDI) and soft mist inhalers (SMI), designed for operation in air and at atmospheric pressure.

SUMMARY OF THE INVENTION lt is an object of the present invention to provide means by which a breathing system for apressurized environment can be adapted for use by a person with asthma, or by a person suffering from other lung or respiratory condition. lt is likewise an object of the present invention to provide a breathing aid system adapted foruse by a person with asthma, or by a person suffering from other lung or respiratory condition, in a pressurized environment.

The above stated first object is met in a dispensing regulator unit comprising a housing whichdefines a dispensing chamber for an inhalable substance; a coupling interface for connectingthe housing to a breathing system; a dispensing channel connecting the dispensing chamberto a breathing gas flow; and a demand valve maneuverable for permitting flow communication between the dispensing chamber and the breathing gas flow upon demand by a user.

The ânlfalable Substance as als-c- mexftšonad En the iaftroductšon may ba one of: a gaseous, aliquid or a dry gav-rider' rnedittal Substance, such as asthma, bronchitis os' CEOPD rnedittârfe, or a Substance for preventing deltydratioiw.

A benefit and technical effect provided by this solution is that medicine or humidity can be administered below the water surface in the form of an aerosol or as a colloidal suspension.

According to one embodiment, the demand valve comprises a dose metering valve or a fixeddiameter orifice. When comprising a dose metering valve, the embodiment offers dispensingof individually sized doses of inhalable substance. When comprising an orifice with a fixeddiameter, the embodiment typically offers aerosolization of a liquid or gas substance for inhalation.

According to one embodiment, a plunger is arranged movable in the housing, the plungerdividing the housing into a compressible dispensing chamber and an expandablecompensation chamber. An elastic member, such as a coiled spring e.g., arranged in thecompensation chamber is effective for urging and biasing the plunger towards the dispensing chamber.

A technical effect provided by the spring-loaded plunger is that it offers an ability to preloadthe dispensing regulator unit with a discharge force component which can be adapted to the subject inhalant, to the environmental pressure and to the breathing gas pressure.

According to one embodiment, a pressure communication channel is arranged connecting thecompensation chamber with the breathing gas flow, the pressure communication channel,which may contain a check valve (95), introducing breathing gas pressure into the compensation chamber.

A technical effect provided by this solution is that a variation in breathing gas pressures between inhalation and exhalation is available as another discharge force component.

According to further embodiments of the invention, the dispensing chamber communicateswith a dose metering chamber of either a fixed or variable volume via a dose release channelwhich is formed in the plunger. The dose metering chamber on the other hand communicates with a supply of inhalable substance via a dose filling channel which is formed in the plunger.

These embodiments provide several technical effects: primarily, the dosage size can in thisway be adapted to customer needs, and the return movement of the plunger is operativelyutilized for preparation of the dispensing regulator unit for a subsequent inhalation and dispensing sequence.

According to one embodiment, the compensation chamber is subjected to environmentalpressure applied from the ambient media. This solution, which may comprise a flexiblediaphragm that separates the compensation chamber from the ambient media, providesseveral technical effects depending on its application: on one hand, when applied to thecompensation chamber, the environmental pressure can be utilized as a discharge forcecomponent during an inhalation sequence, and if applied to the dose metering chamber on theother hand, the environmental pressure can be utilized for compensation of dosage size in relation to environmental pressure.

The embodiments as herein described (e.g.) can have incorporated a measuring device orsimilar for indication of fill level. These can be made as pop out indicators reacting on pressure, proximity sensors, flag indicators, magnetic switch indicators, pin indicators etc.

None of these fill level indicators are shown in any of the drawings, as they are to be found in several other applications, and as such, are already known techniques.

According to one embodiment, another pressure communication channel connects thedispensing chamber to the breathing gas flow, this pressure communication channelintroducing breathing gas pressure into the dispensing chamber, such as via a one-way valve in the pressure communication channel.

This em bodiment operates without the plunger and spring and provides simplicity in design.Operatively, the dispensing chamber is pressurized to static breathing gas pressure via thepressure communication channel during exhalation. At inhalation, the pressurecommunication channel closes whereas the dispensing channel opens for discharge ofinhalable substance into the flow of breathing gas, if the demand valve is actuated. Dischargeinto the breathing gas flow occurs instantly as a result of the slightly reduced static pressureand the high increase in dynamic pressure in the flowing breathing gas. ln this embodiment,release of inhalable substance on demand can be accomplished by means of a usermaneuverable valve that simultaneously opens and closes, or vice versa, the dispensing channel and the pressure communication channel respectively.

According to one embodiment the demand valve is electrically operated. This embodimentprovides the technical advantage of possibility for remote control, and enhanced freedom of installation point in a breathing system. ln several embodiments the housing has coupling means for connecting the dispensingchamber with a canister/container providing supply of inhalable liquid, gaseous or dry powdersubstance. The inhalable substance may be stored under pressure in a pre-pressurized canister/container, if appropriate. ln another aspect of the invention, the above stated second object is met in a breathing aidsystem for a pressurized environment, comprising a breathing system having a high-pressurebreathing gas container, a first pressure reducing valve, a breathing gas connection atmedium or intermediate pressure level, an inhalation device (e.g. a mouthpiece) including asecond pressure reducing valve, delivering breathing gas at inhalation pressure, wherein flowof breathing gas from the high-pressure breathing gas container to the inhalation device isinitiated upon demand by a user. The breathing aid system comprises a dispensing regulatorunit for dispensing inhalable liquid, gaseous or dry powder inhalable substance into breathing gas, the dispensing regulator unit comprising: o a housing defining a dispensing chamber for the inhalable substance, and a coupling interface for connecting the housing to the breathing system,o a dispensing channel connecting the dispensing chamber to a breathing gas flow, o a demand valve maneuverable for permitting flow communication between the dispensing chamber and the breathing gas flow upon demand by the user. ln a further aspect of the invention, the objects are met by a dose metering demand valve fordispensing liquid, gaseous or dry powder inhalable substance into a breathing system for a pressurized environment. The dose metering demand valve comprises: o a plunger movable in a housing, the plunger dividing the housing into a dose release space and a plunger head space, o an elastic member in the plunger head space biasing the plunger towards the dose release space, o a pressure communication channel connecting the plunger head space with thebreathing gas flow, the pressure communication channel introducing breathing gas pressure into the plunger head space, and o wherein the dose release space communicates with a dose metering chamber of either fixed or variable volume via a dose release channel that is formed in the plunger. ln one embodiment, the dose metering chamber communicates with a dispensing chamber ofinhalable Substance via a dose filling channel which is formed in the plunger. Breathing gaspressure is advantageously introduced in the dispensing chamber of inhalable substance via the pressure communication channel.

Further details, advantages and technical effects will appear below from drawings and from the following detailed description of embodiments.

SHORT DESCRIPTION OF THE DRAWINGS Embodiments of the invention will be more closely described below with reference made to the accompanying schematic drawings, wherein Fig. 1 is a simplified illustration and overview of a breathing system for diving, Fig. 2 is a sectional view showing a first embodiment of a dispensing regulator unit fora breathing aid system, Fig. 3 is a sectional view showing a dose metering demand valve for a dispensingregulator unit in dose-metering mode, Fig. 4 is a sectional view showing the dose metering demand valve of Fig. 3 in dose-release mode, Fig. 5 is a sectional view showing a dispensing regulator unit of alternative design,shown in dispensing chamber pressurizing mode, Fig. 6 is a broken away sectional view showing a cut out portion of the dispensingregulator unit of Fig. 5 in medical substance discharging mode, Fig. 7 is a sectional view showing a dispensing regulator unit of alternative design, Fig. 8 is a sectional view showing a dispensing regulator unit and demand valve of yetan alternative design, Fig. 9 is a broken away sectional view showing a portion of a dispensing regulator unit and dose metering valve with a metering chamber of variable volume, responsive to ambient media pressure, and Fig. 10 is a symbol diagram over a breathing aid system comprising a dispensing regulator unit embodiment in accordance with the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS For the detailed disclosure it shall be pointed out that the accom panying drawings are merelyillustrative and not true to scale, and that no conclusions on dimensions or proportions should be based on these schematic drawings.

A breathing system 1 suitable for implementation of a dispensing regulator unit 2 inaccordance with the present invention is illustrated briefly in Fig. 1. The breathingsystem 1 is conventionally composed for unden/vater activities and comprises a high-pressure container 3 suitable for storing breathing gas which may be compressed to apressure in the order of 100-300 bar (a) or 10-30 I\/lPa, typically. A first stage regulator4, which can be responsive to the ambient media pressure (i.e. the water pressure atthe subject depth), reduces the high-pressure gas in the container to an intermediatepressure level in the order of about 10 bar (a) or 1 MPa. Breathing gas at thisintermediate pressure level is conveyed via a flexible hose 5 to a second stageregulator 6, the latter typically comprising a mouthpiece for a biting grip by the user or in some applications a helmet mainly for undenNater working operations.

When re-breathers are used, the CO2 is removed and O2 is recycled while necessary O2 isconstantly given in accordance with the equipment settings and ambient pressure. However,the principle of giving adequate breathing gas to the user while being submerged, is basically the same as the open-circuit shown in Fig. 1.

By means of a restriction valve and a lever mechanism which is actuated upon by a flexiblediaphragm, the second stage regulator 6 is responsive to the ambient media pressure todeliver breathing gas for inhalation at a pressure which is substantially equal to the pressureof the ambient environment. Exhalation of used breathing gas to the ambient is accomplished via an exhaust valve in the second regulator.

The structure and operation of a conventional breathing system for diving is commonly known by persons of the diving community and requires no detailed explanation here.

The dispensing regulator unit 2, the particulars of which will be more closely explained below,can be integrated at various locations in the breathing system 1: on the first stage regulator 4,on the hose 5, or on the second stage regulator 6. Thus, depending on location in thebreathing system, the dispensing regulator unit of the present invention can be equipped tooperate on breathing gas at either of a pressure separately reduced from the first stageregulator or equipped to operate on the reduced intermediate pressure delivered from the firststage regulator, or equipped to operate on the ambient media pressure, as an operative forcecomponent for dispensing of an inhalable substance into the breathing gas. As to the secondstage the dispensing regulator unit may be equipped to operate on the intermediate pressureor, in the case the regulator unit is directly attached onto the second stage (e.g. mouthpiece), equipped to operate on a pressure which may be manually set before diving.

With reference to Fig. 2, one embodiment 20 of the dispensing regulator unit 2 comprises ahousing 21 which is adapted for holding a supply of inhalable substance within its interior. Aplunger 22 is arranged movable in the housing 21. The plunger 22 divides the housing interiorinto a dispensing chamber 23 and a compensation chamber 24. An elastic member, here acoil spring 25, preloads the plunger 22 towards the dispensing chamber 23. A pressurecommunication channel 26 transmits system pressure to the compensation chamber 24. Thedispensing chamber 23 is connectable to a breathing gas passage 27 via a dispensingchannel 28. A demand valve 29 in the dispensing channel 28 is maneuverable for permittingflow communication between the dispensing chamber 23 and the breathing gas passage 27upon demand by the user. ln the schematic illustration of Fig. 2, by way of example, thedemand valve 29 is indicated to be a pivot valve here shown in closed position. A fixeddiameter orifice 30, effective as atomizer or aerosolizer upon discharge of a liquid or gaseoussubstance, may be arranged in the demand valve 29 or optionally arranged in the dispensingchannel 28. Connectors 31 and 32 provide a coupling interface by which the dispensingregulator unit 20 is connectable in flow communication with a breathing gas flow F in thebreathing system. Charging the dispensing chamber 23 with inhalable substance isaccomplished via a fill valve 33/34. An indicator (not shown) may be arranged to indicate the filling level, as appropriate. ln Fig. 2 the dispensing regulator unit 20 is shown in its charged state. lf under inhalation thedemand valve 29 is set in open mode, the dose of substance in the dispensing chamber 23 will be discharged into the breathing gas passage 27. Discharge will result regardless of internal pressure in the dose of substance, filling the dispensing chamber 23 in Fig. 2.Discharge is effectuated and driven by the combined forces of the spring 25 and the systempressure introduced in the compensation chamber 24, the sum of these forces alwaysexceeding the static pressure in a breathing gas flow at the mouth 35 of the dispensingchannel. If appropriate, an inlet 36 to the pressure communication channel 26 may be directed towards the flow F to take full advantage of the dynamic pressure in the breathing gas flow F.

The discharge of inhalable substance into the breathing gas flow F may be further enhancedand accelerated through the utilization of a Venturi effect. The Venturi effect can beaccomplished and enhanced if optionally the breathing gas passage 27 is formed with aregion of reducing inner diameter lDr upstream of the mouth 35 of the dispensing channel asseen in the flow direction F, followed by a region of increasing inner diameter |Di downstream of the mouth 35.

With reference to Figs. 3 and 4, showing a dose metering demand valve 40 in dose-meteringand dose-release modes respectively. The dose metering demand valve 40 can alternativelyserve as a dose metering demand valve in the dispensing regulator unit 20 of Fig. 2, or in any subsequently described embodiment of the invention.

The dose metering demand valve 40 comprises a plunger 41 arranged movable in a housing42. The plunger 41 divides the housing interior into a dose release space 43 and a plungerhead space 44. A spring member 45 preloads the plunger towards the dose release space 43.A pressure communication line 46 transmits breathing gas system pressure, into the plungerhead space 44. A demand valve outlet 47 sets the dose release space 43 in flowcommunication with a breathing gas flow F in the breathing gas passage 48. Connectors 49and 50 provide a coupling interface by which the dose metering demand valve 40 isconnectable in flow communication with a breathing gas flow in the breathing system.Charging the dispensing regulator unit with inhalable substance or medicine is accomplishedvia a fill port (such as 34 in Fig. 2), which may contain a pressure connection and/or check valve, if appropriate. ln dose-metering mode, see Fig. 3, the plunger 41 is forced by the spring 45 and systempressure into an extended position wherein the plunger provides communication between adose metering chamber 52 and a dispensing chamber 53 (illustrated in dashed lines) ofinhalable substance. Filling the dose metering chamber 52 with inhalable substance from the dispensing chamber 53 is accomplished via the plunger fill port 51 and a dose filling channel 54 formed in the plunger. The dose filling channel 54 runs between entries 55 and 56 whichopen in the side of the plunger. The distance between the entries 55, 56 is determined suchthat the entries are simultaneously placed in register with the plunger fill port 51 and the dosemetering chamber 52 respectively. ln this position the dose metering chamber 52 can be filledwith inhalable substance from a pressurized or pre-pressurized dispensing chamber 53. Thepressure required for discharge of inhalable substance from the dispensing chamber 53 intothe dose metering chamber 52 may be introduced via pressure communication line 46 providing breathing gas pressure. ln dose-metering mode, communication via the valve outlet 47 is prevented by the plunger in its extended position. ln dose-release mode, see Fig. 4, the plunger 41 is pushed against the force of the spring 45into a retracted position through the operation of a lever 58, which can be manually orelectrically actuated. ln the retracted position, the dose metering chamber 52 is set in flowcommunication with the dose release space 43 via a dose release channel 59 which runs froma side entry 60 to an exit 61. ln this retracted position of the plunger, the entries 55, 56 to thedose filling channel 54 are blinded and out of register with the fill port 51 and the dosemetering chamber 52. Upon release of the lever 58, the plunger is again extended and drivenby the combined forces of the spring 45 and the system pressure for releasing the inhalable substance in the dose release space 43 into the flow of breathing gas in the passage 48.

Means are advantageously provided for changing the volume of the dose metering chamber52, thereby adapting the size of the dose to user needs. ln Figs. 3 and 4 the means forvarying the volume of the dose metering chamber 52 is schematically indicated by a nut 62which runs on an inner thread 63 to be set at a predetermined insertion depth in the dose metering chamber.

The size of the dose, i.e. the volume of the dose metering chamber 52, may alternatively bemade dependent on the ambient media pressure in order to adapt the medical effect achievedfrom a medical substance, when administered at different ambient pressures and different inhalation gas pressures.

With reference to Fig. 9 a dose metering chamber 52 is formed in a cylindrical cavity, the dosemetering chamber housing a plunger 64 which is movable in the cylindrical cavity. The plunger 64 has an inner end 65 forming a sliding wall to the dose metering chamber 52. The other end 11 of the plunger carries a flange 66 which is journaled in a radially widened extension 67 of thecylindrical cavity (or if appropriate, depending on the physical effect of the specific medicalsubstance in use, also radially narrowed). lf appropriate, depending on the physical effect ofthe specific medical substance in use, the medical substance may be increased withincreasing ambient pressure as opposed to the solution as shown in Fig. 9. A coil spring 68,acting between the flange 66 and a radial shoulder 69 which connects the radii of the dosemetering chamber 52 and the widened extension 67, urges the plunger 64 towards an ultimateextended position corresponding to the maximum possible volume of the dose meteringchamber 52. A retainer ring 70 or similar maintains the plunger and spring seated in the dose metering chamber.

The plunger 64 is responsive to the ambient pressure via an opening 71 in the retainer ring70. Ambient media may either be allowed to act directly towards an outer face 72 of the flange66, or ambient media pressure may if appropriate be transmitted via an elastic diaphragmwhich covers the opening in the retainer ring. lncreasing ambient pressure will urge theplunger further inwards, this way reducing the volume in the dose metering chamber 52. Thevolume of the extension 67 which is defined on that side of the flange which is opposite fromthe face 72 can be ventilated to the ambient or to the breathing system, as appropriate, via acavity 73 formed in the housing 74. An orifice of very small diameter or any other suitabledevice may be arranged between the cavity 73 and the breathing gas channel. This is only anexample of how to avoid pressure entrapment in the cavity 73 and must not be understood asan open communication channel/wide open orifice between cavity 73 and the breathing gas channel Another embodiment 80 of the dispensing regulator unit will now be described with referenceto Figs. 5 and 6, showing the dispensing regulator unit 80 in pressurizing and discharging modes respectively.

The dispensing regulator unit 80 comprises a housing 81 defining a dispensing chamber 82which is adapted for holding a supply of inhalable substance within its interior. The dispensingchamber 82 is connectable to a breathing gas passage 83 via a dispensing channel 84. Ademand valve 85 is maneuverable for permitting flow communication between the dispensingchamber 82 and a breathing gas flow in the passage 83 via the dispensing channel 84 upondemand by the user. Filling the dispensing chamber 82 with inhalable substance is accomplished via either the fill valve 86 or 87. The former optional fill valve 86 is typically for 12 dry powder supply. The latter optional fill valve 87 is typically for gaseous or liquid supply andcontains a pressure connection and check valve, if appropriate. Connectors 89 and 90 providea coupling interface by which the dispensing regulator unit 80 is connectable in flow communication with a breathing gas flow F. ln the embodiment 80, the dispensing chamber 82 is pressurized by system pressure which isintroduced via a pressure communication channel 91 connecting the dispensing chamber 82and the breathing gas passage 83, it can be in parallel with the dispensing channel 84,however not necessarily, though in the drawing shown as such. ln the illustrated embodiment,the demand valve 85 serves for alternating opening and closing the dispensing channel andthe pressure communication channel respectively. To this purpose, the demand valve 85 isrealized as a pushrod formed with first and second restrictions 92 and 93, respectively,located along the circumference of a valve body 94. The length of the valve body 94 betweenthe restrictions is adapted to the distance between the channels 84 and 91 such that only onechannel at the time is placed in register with the associated restriction 92 or 93, and thusopened towards the dispensing chamber, while the other channel is sealed by the valve bodyor vice versa. A check valve 95 in the pressure communication channel 91 prevents back flowfrom the dispensing chamber 82 into the breathing gas passage. This and similarembodiments with a check valve e.g., pressurizing the dispensing and/or compensationchamber, may have a dump valve to enable the pressurized dispensing chamber to be unpressurized, this enabling substance being filled in the dispensing chamber. ln charging mode, see Fig. 5, static pressure is introduced in the dispensing chamber via anopen check valve 95 in the pressure communication channel 91 _ When supply of inhalablesubstance is demanded for during inhalation, the demand valve 85 is pushed to the positionshown in Fig. 6, opening the dispensing channel 84 while simultaneously closing the pressurecommunication channel 91. An instant drop in static pressure in the breathing gas during theinhalation sequence results in discharge of inhalable substance from the dispensing chamber to the breathing gas flow F, driven by the pressure difference.

The demand valve 85 in the embodiment 80 is specifically useful for dispensing of a dry powder substance into the breathing gas.

Next, another embodiment 100 of the dispensing regulator unit will be described with reference to Fig. 7. 13 The dispensing regulator unit 100 comprises a plunger 101 arranged movable in a housing102. The plunger divides the housing interior into a dispensing chamber 103 and acompensation chamber 104. A spring member 105 preloads the plunger towards thedispensing chamber 103. A dispensing channel 106 sets the dispensing chamber 103 in flowcommunication with a breathing gas flow in a breathing gas passage 107. A fixed diameterorifice 108 may be arranged in the dispensing channel 106 to generate aerosolization of aninhalable substance upon discharge. Connectors 109 provide a coupling interface by whichthe dispensing regulator unit 100 is connectable in flow communication with a breathing gasflow in the breathing system. Charging the dispensing chamber 103 with inhalable substanceis accomplished via the fill valve 110, which contains a pressure connection and a checkvalve, if appropriate. A demand valve 111 is realized for example as a pushrod formed with arestriction 112 arranged in series with a valve body 113. The pushrod is biased by a spring114 into the closing position shown in Fig. 7. Driving the pushrod 111 towards the right in Fig.7 sets the dispensing chamber in flow communication with the breathing gas flow via the dispensing channel 106. ln the embodiment 100, the plunger 101 is subjected to ambient media pressure which isapplied to the plunger via a flexible diaphragm 115, sealing the housing 102 and the compensation chamber 104 from the outer environment.

Another embodiment 120 of a dispensing regulator unit and demand valve is shown in Fig. 8.The dispensing regulator unit 120 comprises a housing 121 defining a dispensing chamber122. A dispensing channel 123 sets the dispensing chamber 122 in flow communication with abreathing gas flow F in a breathing gas passage 124. A fixed diameter orifice 125 may bearranged in the dispensing channel 123 to generate aerosolization of inhalable substanceupon discharge. Connectors 126 and 127 provide a coupling interface by which thedispensing regulator unit 120 is connectable in flow communication with a breathing gas flow F in the breathing aid system.

The embodiment 120 comprises an electrically controllable demand valve 128. The demandvalve 128 comprises a valve body 129 which is normally closed and brought into sealingcontact with a valve seat 130 arranged in the mouth of the dispensing channel 123. ln sealingposition, a breathing gas flow can bypass the valve body 129 on each or either side thereof,inside the breathing gas passage 124. ln the illustrated embodiment, the movements of the valve body 129 are driven by an electric motor 131. lnstead of the electric motor 131, an 14 electromagnet or solenoid etc. may be used in alternative embodiments. The valve body isprovided an opening and a closing motion by rotation of a threaded motor shaft 132 whichengages an internal thread 133 in the valve body, while the valve body is prevented fromrotation through the mutual engagement betvveen linear guide elements (not illustrated)formed in the housing and on the exterior of the valve body. The motor 131 is powered froman accumulator 134, whilst driving power may be portioned via a step motor control 135 e.g.Valve motion is initiated by actuation of a contact means 136. The contact means 136, such as a toggle switch e.g., can be designed to react on pressure applied by the user.

Fig. 10 is a symbolic diagram illustrating a breathing aid system 200 in accordance with the present invention.

The breathing aid system 200 of Fig. 10 thus comprises a breathing gas container 201containing breathing gas at high pressure. A first stage regulator 202 contains an adjustablerestriction which, in the subject case, is responsive to the ambient media pressure fordelivering breathing gas at an intermediate pressure to a second stage regulator 203, via aconduit 204. The second stage regulator 203 is responsive to ambient media pressure and tobreathing gas pressures in inhalation and exhalation for delivering breathing gas at a pressurethat is adapted to the pressurized environment, and for ventilation of exhaled gas to the ambient.

A dispensing regulator unit 205 is in the subject case connected to breathing gas ofintermediate pressure level. Physically, the dispensing regulator unit 205 may alternatively beconnected to either of the first or second stage regulators or to the conduit 204 so as tooperate on the breathing gas pressure which is available at each alternative location. Thedispensing regulator unit 205 might comprise, or be filled by, a container 206 containinginhalable substance in liquid, gaseous or solid/powder phase, which is stored in the container206. ln practice, the container 206 may be an integral part of the dispensing regulator unit205. lnhalable substance in the container 206 can be portioned into a dispensing chamber207 via a fill/supply valve 208. The dispensing chamber 207 can be set in flow communicationwith the breathing gas flow in the conduit 204 via a dispensing channel 209, optionallycontaining a fixed diameter orifice 210. A demand valve 211, normally closed, provides flowcommunication from the dispensing chamber to a breathing gas flow in conduit 204 uponactuation by the user. The dispensing chamber 207 has a compressible volume in a housing containing a movable plunger 212, the plunger separating the dispensing chamber 207 from a compensation chamber 213. The compensation chamber 213 is in flow communication withthe intermediate breathing gas pressure via pressure communication channel 214, leadingdynamic and static breathing gas pressure into the compensation chamber for pre-tensioningof the plunger 212 towards the dispensing chamber 207. A spring 215 in the compensation chamber adds to pre-tensioning of the plunger in the direction of discharge and dispensing.

An alternative installation of the dispensing regulator unit 205 is indicated with dashed lines inFig. 10. More precisely, a regulator 216 contains an adjustable restriction which reduces the high-pressure delivered from the breathing gas container 201 to an independent intermediatepressure to be delivered to the dispensing regulator unit 205, thus eliminating the need of the static and dynamic pressurization from the breathing gas intermediate pressure.

The dispensing regulator unit in the above described embodiments may comprise means to indicate or monitor the fill level of the inhalable substance.

Claims (7)

1. A dispensing regulator unit (20; 80; 100; 120) for dispensing liquid, gaseous or drypowder inhalable substance into a breathing system for a pressurized environment, inorder to prevent or relieve problems such as asthma, other breathing difficulties or dehydration, the dispensing regulator unit characterized by: a housing (21; 81; 102; 121) defining a dispensing chamber (23; 53; 82; 103; 122) forthe inhalable substance, and a coupling interface (31, 32; 89, 90; 109; 126, 127) for connecting the housing to the breathing system, a dispensing channel (35; 84; 106; 123) connecting the dispensing chamber (23; 82;103; 122) to a breathing gas flow (F), a demand valve (29; 40; 85; 111; 129) maneuverable for permitting flowcommunication between the dispensing chamber (23; 82; 103; 122) and the breathing gas flow (F) upon demand by a user.

2. The dispensing regulator unit of claim 1, wherein the demand valve comprises a dose metering valve (40) and/or a fixed diameter orifice (30;108).

3. The dispensing regulator unit of claim 1 or 2, comprising a plunger (22; 101) movable in the housing (21; 102), the plunger dividing thehousing into the dispensing chamber (23; 103) and a compensation chamber (24;104), and an elastic member (25; 105) in the compensation chamber biasing the plunger towards the dispensing chamber.

4. The dispensing regulator unit of claim 3, comprising a pressure communication channel(26; 46) connecting the compensation chamber (24; 57) with the breathing gas flow (F),the pressure communication channel (26; 46) introducing breathing gas pressure into the compensation chamber (24 57).

5. The dispensing regulator unit of any previous claim comprising a dose metering demand valve (40), the dose metering demand valve (40) comprising: - a plunger (41) movable in a housing (42), the plunger dividing the housing into a dose release space (43) and a plunger head space (44), and 10. 11. 12. 17 an elastic member (45) in the plunger head space (44) biasing the plunger towards the dose release space, a pressure communication channel (46) connecting the plunger head space (44) withthe breathing gas flow (F), the pressure communication channel (46) introducing breathing gas pressure into the plunger head space (44), wherein the dose release space (43) communicates with a dose metering chamber(52) of either fixed or variable volume via a dose release channel (59) that is formed in the plunger (41). The dispensing regulator unit of claim 5, wherein the dose metering chamber (52) of thedose metering demand valve (40) communicates with a dispensing chamber (53) ofinhalable substance via a dose filling channel (54) which is formed in the plunger (41) of the dose metering demand valve (40). The dispensing regulator unit of claim 6, wherein breathing gas pressure is introduced into the compensation chamber (57) via the pressure communication channel (46). The dispensing regulator unit of claim 3, wherein the compensation chamber (104) is subjected to ambient environment pressure via a flexible diaphragm (115). The dispensing regulator unit of claim 1, comprising a pressure communication channel(91) connecting the dispensing chamber (82) to the breathing gas flow (F), the pressurecommunication channel (91 ), which may contain a check valve (95), introducing breathing gas pressure into the dispensing chamber (82). The dispensing regulator unit of claim 9, comprising a user maneuverable demand valve(85) which simultaneously opens and closes, or vice versa, the pressure communication channel (91) and the dispensing channel (84). The dispensing regulator unit of any previous claim, wherein the housing (81) hascoupling means (86; 87) for connecting the dispensing chamber (82) with a pre-pressurized canister providing supply of inhalable liquid, gaseous or a canister providing dry powder substance. The dispensing regulator unit of any previous claim, wherein the demand valve (128) is electrically operated. 18 13. The dispensing regulator unit of any previous claim, wherein the âralaaiatßie substance isone -c-f: a gaseous. a liquid of a dry powder medical substance. such as asïhnfa, bronchitis or CÜPÜ rnedšcine, cr a samstafffge for prexfentâng deliydratiora. 14. A breathing aid system (200) for a pressurized environment, comprising a breathingsystem having a high-pressure breathing gas container (201 ), a first pressure reducingvalve (202), a medium-pressure breathing gas connection (204), an inhalation device (6)including a second pressure reducing valve (203), delivering breathing gas at inhalationpressure, wherein breathing gas flow from the high-pressure breathing gas container(201) to the inhalation device (6) is initiated upon demand by a user, characterized inthat the breathing aid system comprises a dispensing regulator unit (205, 206, 21 1) fordispensing liquid, gaseous or dry powder inhalable substance into the breathing system, the dispensing regulator unit comprising: a housing (205) defining a dispensing chamber (207) forthe inhalable substance, and a coupling interface for connecting the housing to the breathing system, a dispensing channel (209) connecting the dispensing chamber to a breathing gasflow (204), a demand valve (211) maneuverable for permitting flow communication between the dispensing chamber (207) and the breathing gas flow upon demand by the user. 15. A dose metering demand valve (40) for dispensing liquid, gaseous or dry powderinhalable substance into a breathing system for a pressurized environment, the dose metering demand valve (40) characterized by: a plunger (41) movable in a housing (42), the plunger dividing the housing into a dose release space (43) and a plunger head space (44), an elastic member (45) in the plunger head space (44) biasing the plunger towards the dose release space (43) chamber, a pressure communication channel (46) connecting the compensation chamber (44)with the breathing gas flow (F), the pressure communication channel (46) introducing breathing gas pressure into the plunger head space (44), and 19 wherein the dose release space (43) communicates with a dose metering chamber(52) of either a fixed or variable volume via a dose release channel (59) that is formed in the plunger (41). 1

6. The dose metering demand valve (40) of claim 15, wherein the dose metering chamber5 (52) of the dose metering demand valve (40) communicates with a dispensing chamber(53) of inhalable substance via a dose filling channel (54) which is formed in the plunger (41) of the dose metering demand valve (40). 1

7. The dose metering demand valve (40) of claim 16, wherein breathing gas pressure isintroduced into the dispensing chamber (53) of inhalable substance via the pressure 10 communication channel (46).