US2390236A - Portable field oxygen therapy apparatus - Google Patents

Description

Dec. 4, 1945. w. M, BOOTHBY ET AL 2,390,236

PORTABLE FIELD OXYGEN THERAPY APPARATUS Filed March 23, 1942 5 Sheets-Sheet 1 we 6048 Fi .-1 g |59 '12?' '$52 9s l.: 494|- 98 9 loo |28 am 95 los 93 O lz? Inventor-s'.

W.R.Lovelacelr Dec. 4, 1945. w. M. BooTHBY ETAL 2,390,235

PORTABLE FIELD OXYGEN THERAPY APPARATUS Filed Marsh 2s, 1942 5 sheets-sheet 2 I 32M Inventor-S. u

35 w. M. Boachbg W. R. Love lace 1I B21 wf/M12@ Dec. 4, 1945.

W. M. BOGTHBY ETAL PORTABLE FIELD OXYGEN THERAPY APPARATUS Filed March 2:5, 1942 'Fig-6 5 Sheets-Sheet 3 W. M. Boothb I4 74 46 I me |ez\\"? 7B 4a eo '56 A no2 I l 4 94A 9B 90 |28\ l' l |04 57 I 42 9| Il |17- TM |58 l |53 2\ G l| |44- /1 o IS $05 la 26 25 G O O B WRQ/IZL/ga JI. fft't maag.

Dec. 4, 1945. A wM BooTHBY ET A| 2,390,235

PORTABLE FIELD OXYGEN THERAPY APPARATUS Filed March 23, 1942 5 Sheets-Sheet 4 F1979 74 Fig-8 S4 53 |43 4z |52, .58 Z6 |20 |38/ Q IIS I |3G` i ls (j 32 Irwzn'tor-s:

W. M. Boolrhjog.

R. Lovelace 31 W M. BOOTHBY ETAL PORTABLE FIELD OXYGEN THERAPY APPARATUS Dec. 4, 1945.

Filed March 23, 1942 5 Sheets-Shea?I 5 mm2-(P200 m2 J (Gow mOn OPUmZZOU w.M. Bobthb age 1I W. R. Lovel,

Patented Dec. 4, 1945 PORTABLE FIELD OXYGEN THERAPY APPARATUS l Walter M. Boothby and WilliamRandolph Lovelace, II, Rochester, Minn.

Application March 23, 1942, Serial No. 435,916

(Cl. 12S-191) Claims.

Our application relates to portable eld oxygen therapy apparatus and has for its object to provide a suitable apparatus for permitting economic therapeutic use of oxygen in high concentrations with a closed circuit carbon dioxide absorption means, which shall be light in Weight, easily portable, mounted within a carrying case of compact and effective design, and adapted to be used with all sizes of standard medical oxygen cylinders.

As the art of oxygen therapy has advanced under modern developments, certain conditions are known where it is desirable or essential to supply to individuals a certain gas or mixtures of gases for breathing, particularly oxygen with or without added air. These conditions are, of course, all essentially medical. The types of cases where oxygen supply is essential to preserve life, other than diseases of common knowledge such as pneumonia and the like, may be from injuries suffered, wherein shock, loss of blood and other conditions have reduced the patients resistance to a low point, and quick administration of a high concentration of oxygen, in practice 100 percent oxygen, may make the dilerence between death on the part of the patient or his survival.

`Such conditions are, of course, always pres'- ent in and back of lines of military combat. Under such conditions, where large numbers of wounded or gassed individuals are to be found, it is of the utmost importance in many cases to be able to have quickly at hand, before hospitalization is possible, a means of supplying to the patient the requisite high concentration of oxygen. Under such conditions also, because of the difficulty of having comparatively heavy tanks of oxygen available in large numbers, it is important that supplies of oxygen available are conserved to as great a degree as possible so that such supplies as are available may be used with the fullest effectiveness.

It is a primary object of our invention therefore, to provide, in a compact easily portable arrangement, means for delivering oxygen to a patient, which can be taken from point to point on the eld to be used on injured persons, particularly those wounded by military action, and. whereby not only high concentrationsl of oxygen or 100 percent oxygen can be administered to the patient, but a closed breathing circuit is provided with means for removing carbon dioxide in said circuit so that the oxygen supplied may be repeatedly breathed and rebreathed.

It is, therefore, a further and highly important object of our' invention to provide, in connection with a portable unit including means to quickly set it up in working condition in the eld, a closed breathing circuit, means for removing carbon dioxide from exhalation gases moving therethrough, means for supplying oxygen to the inhale side to be added to the substantially pure oxygen accumulated in a reservoir rebreathing brag' af-ter the carbon dioxide has been removed, and further to automatically increase the supply of oxygen for inhalation during the latter part like in form, wherein the apparatus to be employed is permanently attached to and supported by a base portion of the case and wherein the main bulk of the case comprises a removable cover portion which when removed is adapted, rst, to

expose the operative elements supported by the base portion, and second, to be employed as a table support to hold the parts supported by the base portion in position for use,

It is a further object of our invention to construct relatively the base portion and the cover portion of the case so that the latter can be withdrawn, arranged as a table support and have the base portion and parts carried thereby secured to it as a table support with the utmost quickness and at the same time so that the parts will be rmly and continuously held together in such new position, Where they will be conveniently arranged for eiective use.

It is a further object of our invention to provide supported from the aforesaid base portion of the casing, a container for some granular or broken material adapted to absorb carbon dioxide, such as soda lime, which shall be supported transversely of the casing in such manner that the gases of exhalation will be causedr to pass through the chamber and the carbon dioxide absorbing material therein, which shall be capable of being removed and yet with means for holding it gas-tight in the breathing line.

It is a further object of our invention to provide, in conjunction with the aforesaid base portion of the case, a pair of uprights rigidly held to said base portion and constituting means for supporting the in'strumentalities above referred to, so that when the deep cover portion of the case It is a further object of our invention not only Y to provide means for continuous flow of oxygen entering the closed breathing circuit, but to provide also valve mechanism subject to the negative pressure induced by inhalation which shall automatically increase the ow of oxygen into the breathing line after inhalation has proceeded to a point where the rebreathing bag is exhausted.

It is a further object of our invention to provide a rebreathing bag and connector tube thereto which may be carried Within the'case in a separated condition, in conjunction with means in the case co-operating with means on the rebreathing bag connector whereby the rebreathing bag may be quickly connected in the breathing line in position to be suspended outside the case.

It is a further object of our invention to provide means which may be carried in the case but normally separated from the other appliances for quick connection with any tank of oxygen which may be available, such as small tanks which may be carried from point to point by hand, or large tanks which would require movement from point to point upon some kind of trucking device.

It is a further object of our invention to provide breathing tubes which are connected together and have a single tube going to the mask, and which have branch tubes one for exhalation and the other for inhalation, which together, taken in conjunction with fixed passages in the machine, form the closed breathing circuit, said respective exhaling and inhaling tubes being respectively associated with flap valve constructions operating so that exhalation and inhalation cause flow of gases through the circuit always in one direction.

The full objects and advantages of our invention will more fully appear in the specification hereinafter presented, and the novel features by means of which the abovel noted advantageous results are secured will be particularly pointed out in the claims.

In the drawings illustrating an application of our invention in one form:

Figure 1 is a perspective view of the casing including the field apparatus.

Figure 2 is a plan view with some parts in section of the base portion of the apparatus, showing the general arrangement of parts carried thereby.

Figure 3 is a sectional view taken on the line 3-3 of Figure 2.

Figure 4 is a sectional View taken on the line 4-4 of Figure 2.

Figure 5 is a side elevation view of the entire apparatus set up for operation, indicating oxygen tanks of different sizes conveniently posi, tioned for use.

Figure 6 is a side elevation view taken from the opposite side of the showing of Figure 5, illustrating the tube connections to the rebreathing bag and the mask.

Figure 7 is a detail showing a form of corrugated rubber which may be used for the extended tube connections in the apparatus and going to the mask.

Figure 8 is a sectional elevational view when the apparatus is assembled for operative position, taken substantially along the line 8-9 of Figure 2.

Figure 9 is an enlarged sectional view taken through the valve control mechanism.

Figure 10 is a part sectional view of the valve mechanismv for making connection with the filled oxygen tanks.

Fig. 11 is a diagrammatic view related to the structural showing of the other iigures of the drawings and with appropriate legends applied, showing the travel of the gases in their continuous course from the beginning of the exhalation at the mask to the end of inhalation at the mask.

As illustrated, referring to Figure 1, the casing comprises a base portion I5 and a cover portion I6 held together by hasps I1, I8, I9, and ZIJ, pivotally mounted upon and connected to the deep cover portion I6 in pairs on opposite sides thereof, as indicated in Figures 1, 5 and 6. These hasps are adapted to snap over catch portions 2|, 22, 23 and 24 (see Figure 2), which are fast on opposite sides adjacent upper edges of the base member I5. This base member is also provided with similar catches 25, 26, 21 and 29, which are fast on opposite sides of the base member I5 adjacent the bottom edge thereof as clearly shown in Figures 1 and 5.

From a comparison of these figures, it will be apparent that when the casing is put together for ready transport the hasps I1, I6, I9 and 20 snap over the catches 2 I, 22, 23 and 24 and secure the deep cover member I6 to the base member I5 so that the parts carried by the base member I5 are held within the deep cover member. When in this position, a handle 29 secured to the top wall 30 of the cover member I5 provides a means of carrying the entire assemblage as simply and as conveniently asl an ordinary suitcase may be carried.

When, however, it is desired to put the machine in condition for operation, the hasps I1, I8, I9 and 20 are taken away from the catches 2Il 22, 23 and 24, and the cover portion is lifted olf, exposing the parts theretofore within and protected by said cover portion which are supported by the base member I5. A series of short legs 3l, 32, 33 and 34 projecting upwardly from the corners of the top 30 of the deep cover member I6, then form a ground contact support for said deep cover member I6 when it is inverted. In this inverted position, as shown in Figures 5,- 6 and 8, the cover member I6 will form a table support for the base member I5 and parts carried thereby. By means of the handle I4 the base member I5 is lifted up and set on the top edge of. the cover member I6 and the hasps I1, I8, I9 and 20 are swung upwardly over the catches 25, 26, 21 and 28. The base member thus is held upon the cover member, with all the parts carried by the base member exposed for operative use, and with the base member substantially integral with the cover member, which thus becomes a supporting table for the base member.

Within the side walls 35 and 36 of the base member I6 and secured to said side walls by rivets, bolts, glue, or other suitable securing means, are pieces 31 and 38 which as shown in Figures 2 and 8, extend across the full extent inside the casing base member I5 to engage with their ends the other opposite side walls 39 and 40, .thus becoming in effect integral with the side walls 35 and 35. The central portions of the pieces 31 and 33 are provided withy upright standards 4| and 42, clearly shown in elevation in Figures 5 and 6, and shown in sectional plan in Figure 2. To these uprights the gas administering apparatus is secured so that all essential and operati've parts thereof when the base member is positioned upon` the cover member as shown in Figures 5 and 6, are exposed and. available subject to the control of the operator.

As best shown in Figure 5 a supporting bracket 43 is secured at '|4V andr 45 to the uprights 4| and 4.2. Thisbracket 43 has a depressed portion as shown which receives and supports a cylindrical canister 46 of a cross sectional shape narrower than'r its diameter as clearly indicated in FiguresA .2' and 8. The canister de is held. between a pair of spaced parallel cross bars 41 and 43, Figure 2., which are respectively formed with anglel portions 49, 50, 5| and 521 bolted to the uprights 4| and 42. As shown in Figure 8, the yside walls 53 and 5d of the canister 46 have at their central parts circular openings 55 and 56. An inlet tube 51, Figure 8, passes through an opening in the top. of bar 4l, being held to said bar by a grooved washer 58.. Similarly an outlet tube 59` passes through an opening in the top of bar 43 and is held thereto by a grooved washer 65. The tube 51 has fast thereon a ring or washer 6l. Between the washer 5| and the side wall 53 of canister 45, is. an annular' rubber gasket 63, and

between the inner part of grooved washer SQ andv wall 54 of canister 48 is an annular rubber gasket 63.

An annular piece 54 is provided with a. central threaded opening 65, Figure 2, in which is threaded a knurled thumb screw 55. The piece ed is carried upon arms 61 and 88 which have their ends pivoted in. blocks 69 and i0 secured to the cross bar41. In this man-ner the thumb screw 66 may be swung up or down to bring its point away from or into engagement with a seat 1l, Figure 8, on the outside of the wall 12 forming a continuation of inlet tube 51 into a portion 13 thereof extending at right angles to tube 51.

From the above construction it will be apparent that the canister 45 is removably mounted in the apparatus and yet is held gas-tight when in operative position since, by screwing up on the knurled thumb screw, pressure can be simultaneously put on the rubber gaskets 6| and 63, where by the openings into the canister through which extend the tubes 51 and 59 will be firmly sealed. When, however, it is desired to remove the canis-v ter the knurled thumb screw 6e may be screwed in the opposite direction, the holder made up of arms 61 and 68 may be dropped down and the respective tubes 51 and 58 be withdrawn from the openings 55 and 56 and the canister lifted out. A cap 14 is adapted to open and close the canister.

The tube 13 connects by means of a ilexible tube 15 of corrugated rubbenas shown in Figure 1, withy a connector member 18, Figure 3, which in turn is united with a valve casing i1 having therein a valve chamber 18 normally opening past a flap valve 19 to a chamber 80. The above parts are secured to the cross bar 48. The chamber 89 is provided with a standard spring outlet valve 8|, Figure 3, which permits escape of exhalation gases when pressure builds up after the rebreathing bag has been completely filled.

The chamber 80 also is provided with a nipple 82 which connects by means of a flexible tubing 83, Figure 6, withY one branch 84 of a Y-piece 85 from which extends a tube 85 going to the mask through tube 88, Y-tube branch 84, tubel 83, piece 11, tube 15, and tubes 13 and 51., to the interior of the canister 46 enclosing av body of ma terial for absorbing carbon dioxide; It will bel noted that the end of tube 51 extends into a1 chamber formed by a body of mesh or 'reticulate material 88 held away from the wall 53 of canister 46 so that theexhalation gases are caused tonipple 93 formed on a casting piece 9'4. The nip-V ple 93 discharges into a chamber 95 within casting piece 94, Figure 4'. A nipple 99 is provided with a threaded annular ring 9i.r A rigid tu-befSB has fast thereon and Sealed againstv its outer wall` a rubber sleeve 99 which has an annular head |00 adapted to engage an annular seat |01. onfthe' threaded annular ring 91'. A knurled annular screw cap |02 has a threaded portion |1213` which in conjunction with the threads on the lring. 91A enables the tube 98 readily to bey connected .in :gastight relation with the nipple extension 9S'.- The' tube 98 as shown in Figure 6, carries a depending portion E04 to which is attached a rebreathing bag |05. With this arrangement the` rebre'athingv bag may quickly be attached to and: detached; from the assemblage so that the rebreathingbag may depend outside of the casing as Yclearly shown in Figures 2 and 6.

At the top of chamber isan upwardly opening flap valve |00 which opens into a `chamber |01 formed by an extension |59 of the casting piece 94, said extension being Asecured to the cross bar 48 as shown in Figures 2 and 4. TheY gasesy of exhalation will therefore pass through the passages above described, including the carbonv diloxide absorbent material in the canister .48: and to the rebreathing bag Then if there is further exhalation the pressure will build up in the exhale valve 8l to permit the last part of the eXhalation--the part most heavily charged with carbon dioxide -to pass to atmosphere.

Oxygen is supplied to the apparatus from suit-V able oxygen tanks. Th'ese tanks may be of different sizes such as small tank |08 'or large tank |09 as shown in Figure 5. In either case customary valve controls are employed including a reducing valve 0 and a gauge for indicating the pressure at which gas is being delivered.

Connected with outlet passage from the tank |08 or |09 a block ||2 is provided having a depending nipple 3 with a pin ||4 at its outer end. A tube 5 is provided which is carried loose in the base preferably together with the re'- ducing valve |I0 and gauge |A|| carried loose in the case. The tube ||5 may be of any desiredlength. This tube has at each end thereof, .Figure 5, slip-joint connector pieces ||6 and H1, `respectively. These connector pieces embody a. rotary member including a bayonet slot ||8. This bayonet slot takes over the pin ||4 and by turning the member ||6 or ||1, the tube H5 at one end is connected to the nipple passageway I3` and at the other end to a corresponding nipple passage ||9. The nipple passageway 9 is an structure 81. 'This constitutesthe exhalatienipartu of the breathing line going from the mask 81 |05 until it is fully Elled.

extension from valve casing |20. From the nipple passage ||9 the oxygen passes to a chamber |2| in valve casing |20, and from there goes past a controlling needle valve |2|a to a chamber |22. The needle valve is operated by a knurled hand nut |23. From chamber |22 the gas goes through a passageway |24 to a, ow valve |25, the rate of ow being indicated on a scale |26. From the flow valve the gas goes through tubing |21 through an opening |28 into chamber 95. Oxygen is thus caused to flow continuously from the tank |08 or |09 into chamber 95, the rate of ilow being determined by the flow gauge |26 as indicated on the scale |25 and controlled by the hand nut |23. This oxygen thus joins the gases of exhalation going to the rebreathing bag. and is carried back on inhalation to the lungs of the patient.

From the valve casing |20 extends a tube |29, Figures and 8, which leads to a valve casing |30, Figures 8 and 9. In a valve chamber |3| within casing |30 a valve disc |32 is pressed against a valve seat |33 by means of a spring |34. A pin |35 passes through a tubular guide |36 One end of the pin |35 engages the center of the valve disc |32 and the other end of the pin engages a contact ball |31 on the end of a lever |38 eccentrically mounted with reference to the contact ball |31 at |39. The lever |38 in turn has a finger |40 which engages a contact ball |4| on a lever |42 pivoted at |43 to a casing |44. The levers |38 and |42 are within a chamber |45 inside of casing |44. A diaphragm |46 is sealed at its edges as indicated at |41 into the walls of casing |44 which, as indicated in Figure 8, is substantially circular in its back plan portion. Connected with the end |48 of lever |42 is a plate |49 which' engages the central body portion of the diaphragm |46. The. casing |44 is secured to the upright 42 by means of a collar |50, as shown in Figure 9. The opening through this collar exposes the diaphragm |46 to atmospheric pressure and other openings |5| and |52 further expose the diaphragm to atmospheric pressure. It follows that when the pressure within chamber |45is reduced, air pressure will move the diaphragm inwardly into said chamber, correspondingly moving levers |42 and |38 so that the contact ball |31 engaging the pin |35 will cause the valve disc |32 to be pushed away from valve seat |33, and permit oxygen to ilow into and through chamber |45 and a passageway |53 leading therefrom to the inhale side of the closed breathing circuit as will now be described.

To branch |54 of Y-connector in the breathing line is secured the inhalation tube |55, Figure 6, which connects with a nipple |56, Figure 4, formed on the casing extension |08 and opening into the chamber |01 above ilap valve |06. From this arrangement it follows that when inhalation takes place the iiap valve |06 will be lifted, the gas from rebreathing bag |05 will pass through the tube 98, chamber 95, past ap valve |06 into chamber |01, and from said chamber through extension passageway |56 and tube |55 to the common passageway 86 and mask 81. Along with the gases from the rebreathing bag will go the normal oxygen supply from tube |21 opening into chamber 95 at |28. When the rebreathing bag |05 has been exhausted and is collapsed, the pressure will be lowered through tube 9| and the canister 56 will be emptied of its gas. This lowering of pressure will in turn lower the pressure in branch |51, which branch is connected by tube |58 with the nipple extension |53. The

reduction ofApressure will therefore be communicated to chamber |45 with the result that the diaphragm will cause the lever system to open the oxygen valve and an increase of oxygen will be 5" delivered to the patient.

In chamber |01, Figure 4, is located an inhalation valve construction |59. When the pressure within chamber |01 and the valve member |59 reduces suiciently, the spring held valve disc. |60 will be moved to open to atmosphere through a passageway |6| which communicates past a whistle reed |62 with an opening |63 to atmosphere. This will enable air to be mixed with the mixture of rebreathed gases and oxygen going to the patient and when this occurs the movement of the reed will cause a whistling or musical. sound which will notify the operator that air is being admitted.

As shown in Fig. 11, to which this outline of the course of the gas applies, with supporting references to other gures of the drawings, the course of the gas may be traced as follows:

From the mask 81 through a tube 86 exhalation gases pass through a branch 84 of Y tube 85, through a conduit 83 to and through a valve casing 11 and past check valves 19 therein, Fig. 3, and thence through tube 15 and connector member 13 and through tube 51 past connector member 6|, by means of which soda lime container 46 is removably united by coupling means 6| in the exhale side of the breathing line, Figs. 5 and 8, to and through the soda lime container 46. A corresponding connector member 60 associated with tube 59, Fig. 8, removably connects the soda lime container at its other side with a Y tube 90,Fig. 6.

To one of the branches 9| of said Y tube, a tube 92 makes connection with a nipple 93 extending from a casing 94, Figs. 4 and 6. A lower chamber 95 therein below check valve |06 connects through a branch pipe 98, Figs. 2, 6, and 8, with a rebreathing bag |05 which is removably supported upon arm 98. Chamber 95 is also connected with oxygen supply tube |21. Above valve |06 in casing 94 is a second chamber |01, Fig. 4, from which leads a connector member |56, Figs. 2 and 4. From connector member |56 inhalation tube |55 leads back to Y tube |54 and closes the circuit.

The exhaling side of the closed circuit thus comprises passages and chambers including common tube 86 from mask 81, connector tubes 83 and 13, the soda lime container 46, and connector tubes 90, 9|, 92 to the reservoir rebreathing bag.

Exhalation pressure upon the valve |06 will main--y tain the exhalation side closed at that point. The

inhalation side of the closed circuit likewise has` connection through common mask conduit 86, Y

tube |54, inhalation tube |55, connector |56, valve chamber 9,4, past valve |06 to the reservoir rebreathing bag |05. The inhalation side also may to a limited extent withdraw gas from soda lime container 46, but the negative pressure in tube 83 will hold check valve 19 closed and substantially effect closure of the inhalation side at the reservoir rebreathing bag.

Oxygen supply means is also indicated in the diaphragm. From the oxygen tank |09 oxygen is delivered past known valve and pressure reducing mechanism to the delivery tube ||5, ||9, Fig. 5. From the tube ||9, Fig. 10, the gas goes into a needle valve casing |20 controlled by a customary needle valve operated by valve handle |23, Fig. 10. From there, in such amounts as the operator may determine, oxygen will be delivered from nipple t24, through a tube |25 of `a flow valve, such as that disclosed in Heidbrink Patent 2,073,372, and by tube |31 into rebreathing chamber 95, Figs. 4 and 8. The volume of oxygen being delivered is indicated bythe flow valve gauge |26. When oxygen is so furnished, its delivery will be continuous and in effect to the inhalation side of the breathing circuit. Continuous delivery of oxygenis not, however, always essential.

From the valve casing |20 and below the needle Valve therein, a conduit |29, Figs. 8, 9` and 10, leads to a valve chamber in a casing |44 wherein, as shown in Fig. 9, through action of the diaphragm |46 when pressure is reduced by inhalation Vand emptying of the reservoir rebreathing bag, the valve operating mechanism will release oxygen to flow through tube |53, Y-tube |51, Y-block 90, and back through tubes 9| and 92 into the inhalation breathing line.

The advantages of our invention have appeared to a very considerable degree in the foregoing description. Not only is the apparatus admirably adapted for quick transport to points where emergency use is called for, but it provides special facilities for the admission of oxygen in any desired concentration without undue waste of the expensive oxygen gas. Under normal conditions the breathing circuit will be maintained continuously closed there being just enough admitted by means of controlled delivery through pipe |21 to ycompensate for the loss of oxygen absorbed in the alveolar regions of the lungs and withdrawn by the carbon dioxide absorbent material in the absorber canister. By the means described, the -apparatus may be completely lled with 100% concentration of oxygen before the mask is applied and breathing starts, so that from then on the patient will be breathing substantially pure oxygen` loss through xation of the oxygen of carbon dioxide being made up by the constant delivery from the regulated and controlled source through the flow valve and the tube |21.

When, however, breathing diiculties are encountered so that there is need of additional supply of oxygen over that furnished by the ow valve control, the automatic arrangement will supply the needed added oxygen It is true also that all gases of exhalation going to the rebreathing gag must in the course of their passage through the machine, go through the canister containing carbon dioxide absorbing material, such as soda lime or the like, and have removed therefrom the carbon dioxide coming from the patients lungs.

There is thus provided a complex and efcient closed circuit gas administering mechamsm which may be transported as easily and as conveniently as an ordinary suitcase, which in its inoperative condition is entirely protected and closed. and yet which may be put into operative position with the parts thereof fully exposed and available for use with very little eiort and substantially no consumption of time, and in the eld away from hospital or other fixed medical facilities.

We claim:

l. A portable field oxygen therapy apparatus, comprising a casing having a base portion and a cover portion, said portions being removably connected together, means fo-r controlling the administration of oxygen secured to the base portion and held within the cover portion when the cover portion is in normal closing position, means whereby the cover portion may be removed from the base portion to form a support for the base 5 portion, and means for securing the base portion to the cover portion for completing the operative unit with the gas controlling means exposed.

2. A portable eld oxygen therapy apparatus, comprising a casing having a base portion and a cover portion, means for controlling the administration of oxygen secured to the base portion and held within the cover portion when the cover portion is in normal closing position, means adapted to hold the said portions in such normal closing position so that they may be carried together but which permits separation of the parts, said cover vportion when the parts are so separated being adapted to form a support furthe base portion, and means on the base portion adapting the cover portion to be secured to the base portion to form a support for said oxygen administering means including the same elements which normally hold the base and cover portions together.

3. A portable eld oxygen therapy apparatus, comprising a base portion having secured thereto means for controlling the administration of oxygen held so as `to be exposed above the upper limits of the base portion, a deep cover portion adapted normally to enclose said oxygen administering means and to lbe removably secured to the rbase portion, said cover portion when removed and inverted forming a support for the base portion and said oxygen administering means, `and means for connecting the cover and base lportions together in either of said relative positions.

4. A portable field oxygen therapy apparatus, comprising a base portion having secured thereto means for controlling the administration of oxygen vheld so as to be .exposed above the upper limits of the base portion, a deep cover portion adapted normally to enclose said oxygen administering means and to be removably secured to the base portion, said cover portion when removed and inverted forming a support for the base portion and said oxygen administering means, pivoted hasos on opposite sides radjacent the lower edge of the cover portion when in normal position and the upper edge of the cover when in inverted position, and correspondingly positioned catches adjacent the upper and lower edges`re spectively of opposite sides of the base portion for connecting the cover and base portions together in either of said relative positions.

5. A portable field oxygen therapy apparatus, comprising a box formed with a shallow base portion and a deep cover portion, frame members secured to opposite sides of the base portion and having uprights extending a distance outside of said walls so that said uprights and the parts l carried thereby are adapted to be enclosed within the cover portion, means for controlling the administering of oxygen secured to said uprights so as to be exposed above the upper limits of the base portion, and means removably securing the cover member tothe base portion.

6. A portable eld oxygen therapy apparatus, comprising a box formed with a shallow portion and a deep cover portion, frame members secured to opposite sides of the base portion and having uprights extending a distance outside of said walls so that said uprights and the partsI carried thereby are adapted to be enclosed within the cover portion, means for controlling the administering of oxygen secured to said uprights so as to be exposed above the upper limits of the base portion, pivoted hasps on opposite sides adjacent the lower edges of the cover por- 6 tion when in normal position, and the upper edge of the cover when in inverted position, and correspondingly positioned catches adjacent the upper and lower edges respectively of opposite sides of the base portion for connecting the cover and base portions together in either of said relative positions.

7. A portable field oxygen therapy apparatus, comprising a casing having a shallow base portion and a deep cover portion, said portions being removablyr connected together, and being adapted to be united so that the cover portion will form a table support for the base portion, a container of material for absorbing carbon dioxide supported upon the base portion, a closed breathing circuit extending from a mask and comprising exhalation and inhalation tubes, said container being connected to said exhalation tube, a connection for a rebreathing bag communicating with both the exhalation and inhalation sides of the closed circuit, a rebreathing bag and means removably attaching it to said connection so the rebreathing bag Will be suspended outside of the casing, and means controlling the flow of gases in the closed circuit whereby gases of exhalation move to the rebreathing bag and gases of inhalation move from the rebreathing bag, said gases moving through the container of carbon dioxide absorbent in the same direction.

8. A portable eld oxygen therapy apparatus, comprising a casing having a shallow base portion and a deep cover portion, said portions being removably connected together, and being adapted to be united so that the cover portion will form a table support for the base portion, a container of material for absorbing carbon dioxide supported upon the base portion, a closed breathing circuit extending from a mask and comprising exhalation and inhalation tubes, said container being connected tosaid exhalation tube, a connection for a rebreathing bag communicating with inhalation sides of the closed circuit, a rebreathying bag and means removably attaching it to said connection so the rebreathing bag will be both the exhalation and they suspended outside of the casing, means controlling the flow of gases in the closed circuit whereby gases of exhalation move to the rebreathin bag and gases of inhalation move from the rebreathing bag, said gases moving through the container of carbon dioxide absorbent in the same direction, and means for delivering a continuous stream of oxygen at a. predetermined and controllable rate of flow to the rebreathing bag and the inhale side of the closed breathing circuit.

9. In a portable field oxygen therapy apparatus embodying chambers and passageways to provide a closed breathing circuit with a rebreathing bag connected to both the inhale and the exhale sides thereof and a soda lime container in the exhalation side for removing CO2, a box comprising a portable housing for said instrumentalities to the base of which they are severally attached, a cover completing said housing and adapted in inverted position to support the base and said instrumentalities when out in the field in operative position, and ilexible and extensible means mounted on said base for removably connecting the said instrumentalities with an oxygen tank.

10. In a portable eld oxygen therapy apparatus embodying chambers and passageways to provide a closed breathing circuit with a rebreathing bag connected to both the inhale and the exhale sides thereof and a soda lime container in the exhalation side for removing CO2, a box comprising a portable housing for said instrumentalities to the base of which they are severally attached, a cover completing said housing and adapted in inverted position to support the base and said instrumentalities when out in the eld in operative position, flexible and extensible means mounted on said base for removably connecting the said instrumentalities with an oxygen tank, and means for removably connecting in the system outside the limits of the box a suitably large rebreathing bag.

WALTER M. BOOTHBY. WILLIAM RANDOLPH LOVELACE, II.

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