US3505996A - High pressure gas storage and discharge apparatus - Google Patents

Description

J. J. COWLEY April 14, 1970 HIGH PRESSURE GAS STORAGE AND DISCHARGE APPARATUS Filed March 31, 1967 3 Sheets-Sheet 1 INVENTOR.

JOHN JAMES COWLEY April 14, 1970 J. J. COWLEY 3,505,996

HIGH PRESSURE GAS STORAGE AND DISCHARGE APPARATUS Filed March 51, 1967 3 Sheets-' -Sheei 2 INVENTOR.

JOHN JAMES COWLEY April 14, 1970 I COWLEY 3,505,996

HIGH PRESSURE GAS STORAGE AND DISCHARGE APPARATUS Filed March 31, 1967 3 Sheets-Sheet 5 Inventor JOHN JAMES COWLEY United States Patent 3,505,996 HIGH PRESSURE GAS STORAGE AND DISCHARGE APPARATUS John James Cowley, Toronto, Ontario, Canada, assignor,

by mesne assignments, to Abbott Laboratories, a corporation of Illinois Continuation-in-part of application Ser. No. 448,139, Apr. 14, 1965. This application Mar. 31, 1967, Ser. No. 627,455

Int. Cl. A62b 7/00; A61m 15/00; B67d /62 US. Cl. 128-1453 4 Claims ABSTRACT OF THE DISCLOSURE A high pressure gas storage and discharge apparatus for use with oxygen breathing devices having a high pressure gas storage vessel, capillary tube means defining a metered outlet for the pressure vessel for discharging gas from the pressure vessel at a reduced rate, a thermally conductive metallic heat sink means formed by at least part of the capillary tube means defining a tortuous gas flow path contained wholly within the pressure vessel, a portion of the capillary tube means extending from the pressure vessel, manually releasable sealing means on the portion of the capillary tube means extending from the presure vessel sealing the end of said capillary tube means.

This invention relates to an individual oxygen inhalator device which is personally portable and available for instant emergency use and, in addition may be used as a short term resuscitator if assistance is available and is a continuation-in-part of co-pending application S.N. 448,139, filed Apr. 14, 1965, now Patent No. 3,392,724.

Various types of emergency oxygen inhalators are available, such as those used for escape from burning buildings or other unbreathable atmospheres, and also those used for escape from very high altitude aircraft. Such devices have usually centered around a cylindrical oxygen container of substantial size and volume and have incorporated regulator mechanism and a variety of different breathing devices permitting in some cases the inhalation of pure oxygen and in other cases the inhalation of a mixture of oxygen and air under pressure and in still other cases, of oxygen and atmospheric air, as available. However, while such prior devices have proved entirely satisfactory for the purposes for which they were designed, they were in general suitable for use only by trained personnel such as firemen or civil defense workers or trained airmen, and were entirely unsuitable for use by civilians or by the great majority of military personnel. In addition, such prior devices were portable only in a restricted sense. Usually, they were designed to be carried on a specially designed sling or uniform attachment at the times when they might be required i.e. when fire fighting or entering a dangerous building, or as part of a parachute harness which would in any event be worn by an airman, and they were therefore in general unsuited for incorporation in a personal or individual first aid kit or, as forming part of a standard military pack as for example a gas mask package which would be worn by all military personnel in action. As a result, the distribution of such prior inhalator devices has been relatively restricted, and in a large number of emergency type situations such as may arise in civilian life and in particular in military experience, oxy- 3,505,996 Patented Apr. 14, 1970 gen inhalators have never been available on less than at least thirty minutes notice, and in many cases, only after a very much longer delay with a resultant injury or loss of life in some cases.

In addition, such prior inhalator devices have usually been designed to perform solely as inhalators that is to say as making available free oxygen for breathing by a person who was fully possessed of his faculties and capable of breathing normally, and the design of such equipment has usually proceeded on the basis that where a resuscitator action was required by a person whose ability to breathe was impaired and therefore required assistance, that other resuscitator equipment would be available and that the inhalator equipment would not be required. In actual practice, and in particular in the case of sudden heart attacks or accidental electric shocks or partial drownings, resuscitation is required first for a relatively short period after which inhalation will be sufiicient to complete the recovery. This fact is well recognized and the design of many resuscitators incorporates an optional inhalator function to which the equipment can be switched over after the patient has partially recovered. However, such resuscitator apparatus as has been available in the past is extremely bulky and usually requires one or two persons to carry it and is usually only available at one or two central locations such that the delay in treating the patient renders the equipment virtually useless.

One of the principal obstacles to the production of a small compact inhalator and resuscitator has been the problem of designing a completely safe and reliable high pressure oxygen container which can be mass produced and filled at a very low cost and yet remain completely safe from leakage or explosion under variable conditions. In addition, the design of an eflicient pressure regulator for reducing the very high container pressures in excess of two thousand p.s.i. down to a fraction of one p.s.i. has not previously been accomplished in a manner permitting mass production at low unit cost.

In particular, the customary design of high pressure containers of large diameter cylindrical shape having domed ends is unsuitable for mass production purposes and in addition the working pressure must be maintained several times lower than the bursting pressure since the danger of rupture of such containers is very serious, resulting in a destructive explosion and shattering of the container. For these reasons, such containers are usually filled to only a fraction of their capacity with consequent increase in cost. In addition, the relatively thick metal required for the construction of such large diameter containers results in an unequal distribution of fibre stress with consequent tendency to develop local weaknesses.

It is therefore a general objective of the invention to provide an oxygen inhalator apparatus which is of small compact design, and stores a volume of oxygen sufficient for a brief emergency period of usage and which incorporates high pressure oxygen storage means capable of standing tests several times in excess of normal working pressures and having an indefinite storage life, and which is available for instant use automatically by untrained personnel.

More particularly, it is an objective of the invention to provide an oxygen inhalator apparatus having the foregoing advantages which also combines the function of a resuscitator apparatus for short periods if desired.

More particularly, it is an objective of the invention to provide an oxygen breathing apparatus having the foregoing advantages comprising a small unit package wrapped and hermetically sealed for protection during storage and handling.

More particularly, it is an objective of the invention to provide an oxygen breathing apparatus having the foregoing advantages incorporating efiicient and safe pressure reduction means.

More particularly, it is an objective of the present invention to provide oxygen breathing apparatus having the foregoing advantages incorporating a demand valve regulating flow of oxygen to the user to extend the useful life of the device.

More particularly, it is an objective of the present invention to provide an oxygen breathing apparatus having the foregoing advantages incorporating means for manually applying pressure to provide a resuscitator action if desired.

More particularly, it is an objective of the present invention to provide an oxygen breathing apparatus having the foregoing advantages wherein the act of opening the wrapper for the package automatically extends a face mask and simultaneously automatically breaks the seal of the oxygen pressure container and permits flow of oxygen therefrom.

More particularly, it is an objective of the present invention to provide a high pressure oxygen container of a novel design adapted for mass production and filling by mass production techniques, and capable of being pressure tested after manufacture and filling and before shipment to ensure complete safety of every container so manufactured and filled.

The foregoing and other advantages will become apparent from the following description of a preferred embodiment of the invention which is here made by way of example only with reference to the following drawings in which like reference devices refer to like parts thereof throughout the various views and diagrams, and in which:

FIGURE 1 is a perspective illustration of an oxygen breathing apparatus according to the invention partially cut-away to reveal the construction;

FIGURE 2 is a sectional side elevation of the apparatus shown in FIGURE 1;

FIGURE 3 is an enlarged perspective of a detail of the apparatus shown in FIGURE 1 exploded to reveal the construction thereof;

FIGURE 4 is a perspective illustration of the apparatus of FIGURE 1 folded and wrapped to form a single compact package;

FIGURE 5 is an enlarged sectional view of a detail of FIG. 1;

FIGURE 6 is an enlarged sectional view of a detail of FIG. 1;

FIGURE 7 is an enlarged sectional view of a detail of FIG. 1;

FIGURE 8 is a sectional side elevation of a further embodiment showing an oxygen flow control valve of a design suitable for use in the invention;

FIGURE 9 is a side elevational view of an embodiment of a pressure indicating device suitable for use in association withthe invention in some cases;

FIGURE 10 is a cut-away perspective view of a further embodiment of the invention, showing it in the packed or storage position;

FIGURE 11 is a sectional side elevation of the embodiment of FIGURE 10, showing it in use;

FIGURE 12 is an enlarged sectional view of the sealbreaking and pressure reducing mechanism of the ernbodiment of FIGURE 10; and

FIGURE 13 is a perspective illustration of a further embodiment of pressure reducing and seal-breaking mean.

From FIGURES 1 and 2 it will be seen that the preferred embodiment of the invention comprises a high pressure oxygen container consisting essentially 'of a length of cylindrical tubing 10 wound upon itself in double spiral form to define a generally donut shaped structure adapted to contain oxygen under very high pressure of about 2,000 to 8,000 psi. and providing endurance for ten to thirty minutes of normal inhalator use. Tube 10 is preferably formed of thin metallic tape spirally wound and bonded in known manner to provide tubing of the greatest strength with the thinnest possible wall structure. It will be noted that this tubular construction provides a pressure container having a very small diameter in relation to its volume hence reducing the unit hoop stress and hence reducing the weight of metal required and in turn equalizing the fibre stress across the wall thickness. This factor is further enhanced by the tape wound construction of the preferred embodiment leading to a molecule distribution around the circumference of the tube instead of along its length giving increased strength. The ends of the tubing are closed in any suitable manner, and the coil of tube 10 is preferably fitted within and contained by the generally cylindrical container 11 having a back portion 12 and an open mouth portion 13, which is in turn provided with an annular retaining flange 14 extending therearound for engagement by and with the flexible rubber or plastic face mask 15 which is shaped and adapted to fit over the nose and mouth of an adult person.

Oxygen is communicated from tube 10 to the interior of face mask 15 by means of a simplified pressure reducing system and flow of oxygen is partially regulated by means of a demand valve which also operates to mix the oxygen with air when a person breathes inwardly. The pressure reducing mechanism consists essentially of capillary tube 16 communicating with one end of tube 10 and having a metering jet device 17 located therewithin which is dimensioned to permit only a very restricted flow of oxygen therethrough, preferably being in the region of about two to four one-thousandths of an inch in diameter. Capillary tube 16 is extended away from tube 10 and is provided with a closed end 18 having a neck portion 19 of reduced diameter formed therein which is weakened and adapted to be fractured easily to permit fiow of oxygen to take place. Closed end 18 and neck portion 19 are completely enclosed within an over-size plastic sleeve 20 which is clamped firmly around tube 16 by means of clamping ring 21, the other end of tube 20 being closed. Tube 20 is preferably formed of relatively soft flexible material such as to permit manipulation of end portion 18 and neck 19 on capillary tube 16 to permit the same to be readily broken. A junction tube 22 of similar plastic material connects from tube 20 with the raised block portion 23 fastened to the back wall 12 of container 11. It will be understood that raised block portion 23 will in fact be of a thickness only slightly greater than the outside diameter of plastic tube 22, and is here shown greatly enlarged for the sake of clarity. Block portion 23 is provided with a central opening 24 extending therethrough from front to back and making communication with a corresponding opening 25 formed in back wall 12. Opening 25 is surrounded by an annular flange 26 which is provided on back wall 12 for making sealing engagement with the rubber expansion bag 27 which is provided for accumulating oxygen flowing from tube 10 continuously to provide a large volume low pressure storage of sufiicient oxygen to be at least sutficient for one deep breath or inhalation. Back portion 12 is also provided with a series of :air entry ports 28 for admitting atmospheric air to the interior thereof which are normally closed by the rubber or plastic flap member 29 which is fastened to the inner side of back wall 12 and provides a simple form of one way valve action. Mixing of atmospheric air with oxygen is achieved by means of the diaphragm member 30 extending over substantially the entire inner surface of back wall 12 being raised upwardly over the block portion 23 and provided with a stiffened central disc portion 31 corresponding substantially to the diameter of block portion 23. Disc portion 31 and diaphragm 30 are provided with a series of air and oxygen mixture passages 32 extending therethrough and on the interior of disc portion 31 there is provided the generally firusto conical valve member 33 shaped to make sealing engagement with block portion 23 and normally closing central opening 24 thereof, the spring finger 34 or any other suitable biasing means being provided to maintain the same in its normally closed position. It will be understood that the biasing pressure of spring finger 34 is very slight and such as may be readily overcome by a normal adult person inhaling within the face mask 15 thereby reducing the pressure therewithin and tending to raise diaphragm 30.

In order to provide for instantaneous operation automatic means are provided for the fracturing of closed end 18 at neck portion 19. Such means comprise the extended wire arm member 35 which comprises one end of the hair spring 36 coiled around post 37 which is in turn fixed to bracket 38 which may be fastened in position by anysuitable means within the interior of casing 11. The free end of arm 35 is provided with an upstanding retaining pin 39 for engagement with any suitable means such as cardboard disc 40 which may be shaped and adapted to fit within the inner diameter of retaining flange 14 of housing 11 and provided with a tag 41. Removal of cardboard disc 40 will release arm 35 and spring 36 will thereupon swing arm 35 in an anti-clockwise direction braking closed end 18 of capillary tube 16. In order to complete the package any suitable covering means such as the plastic wrapper 42 maybe provided for retaining face mask 15 in a closed infolded position, substantially as shown in FIGURE 3, and also for retaining expansion bag 27 in a folded or stored position and preventing damage thereof. Any suitable means (not shown) such as a tear strip may be provided in wrapper 42 for facilitating the removal thereof in known manner.

According to a further embodiment of the invention where the inhalator may possibly be only partially used, it may be considered desirable to provide means for ter minating flow of oxygen from tube so as to enable the unused portion thereof to be retained therewithin a ainst further need. A suitable valve means is shown in FIGURE 8 and may comprise an oversized sleeve portion 43 adapted to fit around the outside diameter of capillary tube which may preferably be cut in two and contains within its interior a cylindrical ball bearing valve member 44 adapted to make sealing engagement with rubber O-ring 45 which abuts against an exposed end of capillary tube 16 and which is urged into such sealing engagement by means of spring 46 which is itself retained in position within sleeve 43 by means of the other exposed end of capillary tube 16. Valve member 44 is moved off O-ring 45 to permit flow of oxygen by means of operating rod 46a extending upwardly through capillary tube 1 6 and provided with a manually operably pressure button (not shown) for depression of member 44. In this embodiment, it may also be necessary to provide a crude form of pressure indicating means to give some indication of the volume of oxygen remaining within tubes 10. Such pressure indicating means may comprise a further capillary tube 47 communicating with the interior of tube 10 from any suitable point therealong which would in the form of a spiral 48 at its free end at the innermost point of spiral 48 is provided with a needle 49 which may indicate a position along a dial 50 if desired.

In addition, filling may be accomplished at one end of tube 10 by means of a further capillary tube 51 the end of which is closed as by silver soldering at 52.

In operation, a user will simply tear off the wrapper 42 and pull at tag 41 thereby unfolding the face mask 15 and also releasing arm 35 which thereupon is swung violently across closed end 18 of capillary tube 16 breaking it as at neck portion 19 and permitting oxygen to flow into plastic tube 22. Such flow of oxygen as takes place will of course be only as great as is permitted by the metering jet 17 fitted within capillary tube 16 and thus is so arranged and designed as to correspond to about the normal rate of breathing of an adult person. Obviously, such escape of oxygen will be continuous and oxygen will flow slowly but steadily down plastic tube 22 into central opening 24 of block 23 and from there into expansion bag 27. Bag 27 will have been released and unfolded by removal of wrapper 42 and will thereupon slowly fill and expand in response to the increasing volume of oxygen flowing thereinto, such filling and expansion taking place within relatively short space of time. The user, as soon as cardboard disc 40 has been removed and discarded will place the face mask 15 which is then fully extended due to inherent resiliency over his nose and mouth and commence to breathe. Inhalation within the face mask 15 will cause a reduction of pressure thereby lifting diaphragm 30 and in turn lifting valve member 33 off block portion 23 and permitting oxygen to flow from expansion bag 27 into the space between block 23 and diaphragm 30 where it will be mixed with air drawn inwardly through air openings 28 and become mixed and pass as a mixture of air and oxygen through openings 32 into face mask and into the lungs of the user. As soon as the lungs are filled, the reduction of pressure within face mask 15 will stop and the slight spring biasing action of finger 34 will reassert itself and press diaphragm 30 downwardly thereby pressing valye members .33 onto block portion 23. When this occurs, the flow of oxygen which is continuing from plastic tube 22 will then be redirected into expansion bag 27 where it will gradually accumulate until the next breath is taken.

If it is desired to use the instant device as an emergency form of resuscitator then a second person or an assistant will be required, since in general, the patient who requires resuscitation will be incapable of assisting himself, and the assistant will go through the same steps as before for opening the package and extending the face mask 15.

After this, he will place the face mask 15 firmly over the nose and mouth of the patient and, as soon as bag 27 has become extended he may simply apply manual pressure to the same thereby forcing oxygen from bag 27 under pressure to overcome the spring biasing of finger 34 and raise diaphragm 30 and valve member 33 off block 23 and permit pure oxygen to flow through openings 32 into the lungs of the patient. Reverse flow of oxygen up pipe 22 and into tube 10 will of course be impossible due to the very substantial back pressure of oxygen within tube 10, and, outward flow or escape of oxygen to the atmosphere through openings 28 will be prevented by flap member 29. While this resuscitator action will obviously not be precisely engineered in the sense that the pressure of the oxygen being forced into the patients lungs may vary, relatively little experience will suflice to teach an operator approximately how much hand pressure on bag 27 is required, and, depending upon the availability of other help at the scene of the accident, such resuscitation with pure oxygen may be coupled with attempts at artificial respiration in known manner and may also be rendered at intervals, interspersed with mouth to mouth resuscitation in known manner, the precise nature and extent of the resuscitator use being dependent upon the particular circumstances and the judgment of the individuals concerned.

According to the further embodiment of the invention illustrated in FIGURES 10, 11, and 12, the design and operation of the unit is still further simplified by building an oxygen mask in the form of an inflatable bag which also cooperates to act as an accumulator or substantial volumes of oxygen at breathable pressures, thereby dispensing with the need for an expansion bag separate from the mask, as in the embodiment of FIGURE 1.

In addition the admixture of air and pure oxygen within the mask is dispensed with thereby further simplifying the construction.

According to this further embodiment, the compressed oxygen storage is provided for by means of a coil tube 60 fitted within a generally cylindrical container 61 having a closed back portion 62 and an open mouth portion 63. A retaining flange 64 extends around open mouth 63 for the purpose of engaging the outer surface of the flexible bag member 65. Bag member 65 is of an annular donut shape and is provided with inner and outer side walls 65a and 65b. Inner side walls 65a may be slit as at 66 to permit restricted flow of oxygen into the enclosed space to flow around the nose and mouth of a user, as shown schematically in FIGURE 11. In order to communicate oxygen from the tube 60 to the interior of bag 65, there is provided a capillary tube member 67 having one end attached to any convenient portion of tube 60 and having fitted therewithin a metering jet 68 for providing the flow control and pressure reduction required to drop the storage pressure of approximately 3,000 p.s.i. to'around p.s.i. or less. The other end of tube 67 is contained within housing 69 which is preferably fastened to back wall 62 by means such as for example screws 70. Tube 67 is sealed as at 71 and is provided with a neck portion 72 of reduced diameter which is thereby weakened and adapted to be fractured easily to permit flow of oxygen to take place. End portion 71, weakened portion 72 and an adjacent portion of tube 67 are all enclosed within a flexible plastic or rubber sleeve 73 which is sealed around tube 67 as by band 74, and sleeve 73 extends outwardly from casing 69 and communicates with the interior of bag 65. In order to produce a clean fracture of tube 67 at neck portion 72, a spring member 75 is provided within casing 69 fastened as by spot welding at one end thereof to casing 69 and being so formed and pretensioned as to be biassed into normal engagement with neck portion 72, through sleeve 73 and being of sufficient spring pre-tension to fracture the same. Spring member 75 is retained normally out of engagement with neck portion 72 by means of the safety pin or wire 76 passing through small openings 77 provided on either side of casing 69 for the purpose. The other end of pin or wire 76 extends perpendicularly away from casing 69 and is provided with a finger engaging loop or ring 78. In order to make a clean well-finished package, a disc of cardboard or the like material such as 79 may be provided for retaining bag member 65 in its collapsed condition (as shown in FIGURE and in this case, ring portion 78 of pin 76 is preferably located on the exterior of cardboard disc 79 whereby a single pull on ring 78 will remove cardboard disc 79 and simultaneously cause rupturing of neck portion 72 thereby causing bag 65 to become filled with oxygen at a pressure slightly in excess of atmospheric pressure. Upon bag 65 being fully distended it will be found to adopt a mask-like shape substantially as shown in FIGURE 11 and oxygen will then flow continuously therefrom through the outlet means, which in this case are provided by holes or perforations 66 as stated.

Upon a resuscitator action being desired, the-entire unit is then merely forced onto the face of the patient thereby applying additional pressure to bag 65 causing an increased flow of oxygen therefrom which, since it cannot escape around the face of the patient is thereby applied to the patients nose and mouth and provides a resuscitator action. In normal use however, the inhalator action will be sufficient and the patient will merely breathe deeply from the space within the inner wall 65a of bag 65 while lightly pressing the mask or bag 65 to the face. The reduction in pressure resulting from the inhalation will tend to collapse the bag 65 and permit the entire contents to fiow into the lungs of the patient. Upon breathing out the bag 65 is released and can again accumulate oxygen and become distended by further flow of oxygen. For this purpose, the flow of oxygen is controlled by the short specially made metering tube or jet 68 which allows the flow of the oxygen to produce about twelve to fifteen breaths per minute initially for the first minute, tapering to about eight to ten breaths per minute after the first five minutes thereafter tapering to zero in about twelve minutes, so that a patient is supplied with an excess amount of pure oxygen during the initial stages of revival and after about five minutes his natural breathing is supplemented by pure oxygen so that if after ten minutes he is still not recovered it is necessary to use a second unit.

The volume of the mask or bag 65 is sized so as to contain approximately one breath of oxygen or about .3 litre and the flow rate adjusted so that the mask 65 will refill during a breathe out period but if no breath is drawn then it will discharge continuously into the air from the slits 66.

Where the original oxygen supply is absolutely pure and free from water vapour the foregoing apparatus will function satisfactorily notwithstanding the freezing effect caused by discharge of a highly compressed gas. However, even minute quantities of water vapour in the supply can cause freezing in the capillary tube nozzle and block escape of oxygen.

This problem can be overcome by making the escaping gas follow a long tortuous exit path thereby permitting a slight enlargement of the diameter of the escape orifice, and also by incorporating a quality of highly conductive metal such as copper thermally conductively associated with such orifice acting as a form of reverse heat sink, capable of giving up heat readily to avoid freezing at any one location.

One form of apparatus suitable for this purpose is shown in FIGURE 13 and comprises a length of copper capillary tube 80, about 30 inches long in this case and of an internal diameter of about 0.005 inch, i.e. somewhat greater than capillary tube nozzle 17 or 67. Tube 80 is wound in a tight spiral to form a tortuous flow path or labyrinth 81 around which the gas must flow, and has an open end at 82 and an extension 83 sealed at 84. Labyrinth 81 and open end 82 are located wholly within tubular pressure vessel 10 or 60, and extension 83 is contained within and supported by support tube 85. Sealed end 84 extends a short distance beyond support tube 85 and is bent over in the shape of a crook and provided with a weakened zone or neck at 86. Pull string 87 is attached to sealed end 84 which is preferably located within the inflatable mask 65 of the embodiment of FIG- URES 10 and 11, although other suitable arrangements may be made in the case of the embodiment of FIG- URE 1. Upon pulling of string 87 sealed end 84 is broken at neck 86 and gas will escape therefrom. The somewhat greater bore of tube 80 will greatly reduce local blockage due to freezing while the rate of flow of gas is maintained the same due to the very much greater length of tube 80 and the tortuous flow path of the gas. In addition, any local freezing effect at any particular place in the tube 80, will be balanced by heat flowing from other paths of tube 80 which is of sufficient mass that, given an average range of storage temperatures, heat will be available to an extent sutficient to overcome such a local effect.

What I claim is:

1. High pressure gas storage and discharge apparatus, for use in association with devices such as oxygen breathing device, and comprising:

a high pressure gas storage vessel;

capillary tube means defining a metered outlet for said pressure vessel and adapted to discharge gas from said pressure vessel at a reduced rate;

a thermally conductive metallic heat sink means formed by at least part of said capillary tube means defining a tortuous gas flow path contained wholly within said pressure vessel;

a portion of said capillary tube means extending from said pressure vessel;

manually releasable sealing means on said portion of said capillary tube means extending from said pressure vessel sealing the outlet and end of said capillary tube means;

face mask means; and

means connecting said metered outlet thereto discharging said gas into said face mask means.

2. The apparatus as claimed in claim 1 including low pressure gas accumulator means connected to said metered outlet for receiving gas discharged therefrom.

3. The apparatus as claimed in claim 1 wherein said face mask means comprises a torodial inflatable resilient bag adapted to conform to the face of a user when infiated, means connecting said metered outlet to the interior of said bag, and gas outlet openings in said bag adapted to provide flow of said gas from said bag to the user.

4. The apparatus as claimed in claim 1 including:.

support tube means extending from said pressure vessel around at least part of said capillary tube means and wherein said face mask means comprises an inflatable resilient bag adapted to conform to the face of a user of said rbag; means connecting said capillary tube means to the interior of said bag; and gas outlet openings in said bag adapted to provide flow of said gas from said bag to the user.

References Cited UNITED STATES PATENTS 8/1914 Johnston .L 12s 202 12/1940 Mejean -5. l28205 7/1941 Lombard l28205 XR 12/1951 Stout 222-3 2/1956 Alfery et a1. 222-5 7/1960 Ziherl et a1 l28203 7/1962 Updegraff l28206 XR 10/1963 Richards 128146.6 XR 6/1964 Gattone 128-205 9/1965 Bartlett 128145.8 2/1966 Leika 239--134 XR RICHARD A. GAUDET, Primary Examiner K. L. HOWELL, Assistant Examiner US. Cl. X.R.

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