US2586677A - Apparatus for the administration of inhalant gas mixtures - Google Patents

Description

Feb. 19, 1952 H. R. MARRETT APPARATUS FOR THE ADMINISTRATION OF INHALANT GAS MIXTURES 6 Sheets-Sheet 2 Filed Feb. 26, 1948 INI/EN T0 Q:

Feb. 19, 1952 H. R. MARRETT APPARATUS FOR THE ADMINISTRATION OF INHALANT GAS MIXTURES e Sheets-Sheet 3 Filed Feb. 26, 1948 APPARATUS FOR THE ADMINISTRATION OF INHALANT GAS MIXTURES 6 Sheets-Sheet 4 Filed Feb. 26, 1948 FIG.4

A rT M YS Feb. 19, 1952 H. R. MARRETT APPARATUS FOR THE ADMINISTRATION OF INHALANT GAS MIXTURES 6 Sheets-Sheet 5 Filed Feb. 26, 1948 FIGS M2? sys Feb. 19, 1952 H. R. MARRETT APPARATUS FOR THE ADMINISTRATION OF INHALANT GAS MIXTURES 6 Sheets-Sheet 6 Filed Feb. 26, 1948 INVENTMQ', 4 W n 1U!" Patented Feb. 19, 1952 APPARATUS FOR THE ADMINISTRATION OF INHALANT GAS IVIIXTURES Henry Rex Marrett, Coventry, England, assignor to Airmed Limited, Harcourt House, London County, England Application February 26, 1948, Serial No. 11,124 In Great Britain November 6, 1346 13 Claims.

This invention relates to improvements in connection with apparatus for the administration of inhalant gas mixtures, such as anesthetics.

, In the standard type of closed circuit apparatus used for administering anesthetics there are two main circuits which are interconnected, viz: the patients circuit, incorporating a carbon dioxide absorber and ether vaporizer, and the basal gas circuit. The patients circuit includes inlet and outlet valves for the patients breath, a soda lime container for the removal of carbon-dioxide, a vaporizer containing liquid ether or other volatile liquid, a re-breathing reservoir or rubber bag, and metering valves for varying the amount of gas which it is desired to pass through the soda lime container and/or the vaporizer. The basal gas circuit includes a number of metering valves for the admission of a controlled quantity of one or more basal gases such as nitrous oxide, carbon dioxide, cyclo-propane or oxygen and one or more Vaporizers containing volatile liquids such as ether, trichlorethylene or chloroform, and valves permitting the flow of basal gases to contact the vapor or volatile liquids in the Vaporizers before the basal gas flow joins the patients circuit.

In apparatus of this type, there is always the danger that, when brought into use, the operator may erroneously place both the soda lime container and the trichlorethylene vaporizer in circuit together, which would of course result in the decomposition of the trichlorethylene.

It is an object of the present invention to provide an improved form or combinational construction of apparatus for the administration of inhalant gases which, in addition to being port'- abie, will withstand rough usage without developing leaks and in which all controls are arranged in a compact and easily accessible relationship.

It is a further object of the invention to provide an automatic locking device, whereby, when the gases are being passed through the soda lime container it is rendered impossible to introduce trichlorethylene into the circuit and, similarly, when the gases are being passed through the trichlorethylene vaporizer it is rendered impossibleto divert the gases through the soda lime container.

A still further object of the invention is to provide a construction of apparatus of the designated character which incorporates a plurality of valves by means of which complete control may be obtained of the concentration of the anesthetic vapors admixed with gases to be adminstered to the patient.

Apreferred embodiment of the invention will now be described with reference to the accompanying drawings in which:

Fig. 1 is a, front elevation of the compacted apparatus unit;

Fig. 2 is a side elevation thereof partly in section on the line II-'-II of Fig. 4;

D Fig.' 3 is a section on the line III--III of Fig. 4;

Figs. 4 and 5 are different cross-sectional plan views taken respectively on the lines IV-IV and VV of Fig. 2

Fig. 6 is a part section on the line VIVI of Fig.3;

v Figs. 7 and 8 are cross-sections taken respectively on the lines VII-VII and VIIL-VIII of Fig. 3; and

Fig. 9 is a cross-section of the valve drum looking device included in the improved structure of the invention.

Referring now to'the structural embodiment of the invention illustrated in Figs. ,1 to 9 of the drawings, the apparatus assembly includes a unitary head 2| in the general form of a casing. This head is provided, at the front end of the assembly, with an inlet connection 4 and an outlet connection 3 (see Figs. 1 and 4) for connection to the tubes of the patients face mask (not shown) said inlet connection 4 aiid outlet connection 3 being each provided with a non-return valve. One of these valves, namely valve 2 of inlet 4, is shown in Fig. 3, a similar valvebeing located in the outlet 3. Non-return valves are enclosed in duplicative housings 22 having transparent covers 22a so that the functioning or said valves may be readily observed.

Also on the front of the unitary head 2|, there is provided a passage M for the rebreathin bag 6 (Fig. 3). Adjacent to said passage a bank of flow-meters 23 is mounted upon the unitary head 2 I, the outlet from the flow-meters for the basal gases leading to an inlet pasage 8 (Figs. 4 and 2) in the head for introduction of basal gas or gases to the system. As shown, the .inlet and outlet connections 4 and 3, the valve housings 22 for the non-return valves and 2, the passage M to the rebreathing bag 6 (Fig. 3) and the flow-meters 23 for the basal gases are all located at the front of the unitary head 2| for ease of observation and control.

Mounted or connectively assembled on the underside of the unitary head 2| are the soda lime container 5, the ether vaporizer I and the trichlorethylene vaporizer 9, these being disposed in close relationship to each other.

Inserted concentrically in cylinders 30, 3|, 32 (Fig. 4) extending vertically downward from the top of the unitary head 2I and forming, in efiect, a part of said head, are three vertical drums II], II, I2 (Fig. 4) mounted rotatably in said cylinders respectively over the soda, lime container 5, the ether vaporizer I and the trichlorethylene vaporizer 9 (see also Figs. 2;and 3). V are provided with ports and compartments which cooperate with ports and passageways provided in or connected with said cylinders or with parts of the unitary head 2I, as isv hereinafter more fully explained, and accordingly act as.valves.

The rotatable drum II] (over the soda lime container), hereinafter called thefhain drum, has two settings controlling the now of gases in what is termed and hereinafter described as the patients circuit, that is, eithl ar-(ct) throughthe soda lime container 5 or (b) by by-passing-the soda lime container 5. The other two rotatable drums II and I2, hereinafter referred to as the ether drum and the. trichlorethylene drum, respectively control the admission of the patients breath or any desired proportionthere'oftothe ether vaporizer I, and the now of" basal gases or any desired proportion of such gases through one or both of the vaporizers'l and, 9.

The soda lime conta ners is surrounded by an outer casing 5a (seeFigs. 1 a'nfd2) and'is supported on the inside of a knurled closure 24, screwed to the outer "side ofsaid ea in by means of angle brackets 25. A spring, such asa circular coil spring (not shown), is interposed between said closure 24 and the bottomedge of the soda lime-container 5, the bracketsiibeing provided with vertical slots 2521 to take up the movement of the brackets as theclosure 24 is .screwed'onto 1:

the outer casing carer securing the s'odalime container 5 in position. In the upper edge of the container an inset sealing ring 26 (Fig, 3) is provided to effect a tight closure contact. The outer casing 5a is also provided with guides 21 (Fig. 3) to locate the container 5', centrally when it is inserted in the outer casin'gSd.

The container 5 is provided'with a gauze layer 51) at its bottom to prevent the soda lime from entering the circuit conduits and, below said gauze level, arcw of ports 5c communicating with the annular passage formed around said container between ita'n'd' the outer casing 5a. This annular passage communicates with the passage I4 to the rebreath'er bag 5 through openings 38 controlled by a valve as willlater appear.

Referring now more particularly toFigures' and 5, three passages I5, IQand 28,1interconnect the three cylinders 3D, 31 and 32 in the unitary head 2| in which the main drum I0, the ether drum II and the trichlorethylene drum I2' rtate. These interconnecting passages I5, I9, 28 have circuit opening to a branch 29 leading from one of the same (in this instance passage I) to the inspiratory non-return valve in the outlet connection 3 of the apparatus.

The main drum I0 is provided with a vertical partition 33 dividing it depthwise on the linesof a chord or segment into two space portions I0 and I0 the portion II) being closed over or capped at its top by a horizontal plate 34 extend ing from the Wall of the drum to said vertical partition 33. The base or bottom cross-plate 34a of the drum II! is provided with the four ports Illa, [027, I00 and IM which are adapted to register, in one or the other of the alternative settings of drum I0, respectively with ports IIIal, I01), I00 and Illd (see Figs. 3, 5 and 6) formed in the bottom 35 of the unitary head 2 I. In addition, the circumferential wall of the main drum Thesedrums- III is provided with four ports IIle, i0 Illg and IOh (see Figs. 3 and 5), which can be brought into registration with the passage I3 (Fig. 6) leading to the expiratory non-return valve 2 in the inlet connection 4 of the apparatus and also with the passages I5 and 28 connecting the cylinders 3! and 32 with the cylinder 30. Thus the main drum Ill may be said to be interconnectable with the ether and trichlorethylene vaporizer .drumsl I andIZrespectively.

The circumferential wall of cylinder 3!) (Fig. 3) extends below the bottom plate 35 of the head 2I,down to the open top of the soda lime container 5 in contactwith the sealing ring 26 in the latter, and the space thereof between the top of said sodalime container and the bottom plate 1 35- of the head is subdivided by vertical partitions 36 and 31 (Figs. 3 and 6). These last-named partitions comprise plates bent right-angularly or otherwise formed at their lower ends to provide'closure'plates' 36d and-31a over the soda lime container (Figs. 3 and-6). The outer casing 5a of the soda lime container '5' terminates at or in the downwardly extended- Wall of cylinder above a" row of ports 38- (Fig. fi'lpreviously mentioned. The positionings of theaforementioned ports Ifla lflb I0c and Ifld in the bottom plate ofthe head relative-to said vertical partitions 36 and 31 withinthe-1ower end of cylinder 35 are shown in dotted-lines in Fig. 6.- a

The ether drum Ii in cylinder 3I'is provided with vertical partitions Hand 40- (Fig. 5) dividing the annular space-of saiddrum, between.- a central filling passage 4I'-thereinandtheinner peripheral wall thereof, into twoportions I I and I I said partitions extending through only a portion of the depth of the drum." These divided space portions II and II of the-drum are-covered over by a horizontal plate 42 (Fig. 2); supported on this horizontal plate 42 are a rightangular plate member 43, onthe line of achord (Figs. 2 and 4)-defining-a gas passage 43a and-a v-shaped member 44- on the linesof a segment forming a gas passage 44a leading to a-tube- I'I extending down through the -central passage-t l into the ether vaporizer I. The bottom-plate (not numbered) of the drum'l I is provided with a. port iIa (Figs. 2 and 5) adapted to register with a portIIb in the bottom plate 35-of the head 2|. The cylindrical wall of drum II is provided at an upper levelwith ports He and IId- (Fig. 4) adapted to register respectivelywith ports He and III in the cylinder 3|, so as to lead basal gases from the passage 8a (extending from-cylinder 32) into thegas-passageMa of the drum II-and from the-gas passage 43d of the drum to an exit passage 45 extending from the cylinder 3I. This last-named passage 45 leads by way of a banjo connection 45a to the valve housing 22of the inspiratory'non return valve 3. At a lower level in the cylindrical Wall of drum II, further ports Hg and H11, (Fig; 5) are provided to register with ports (not'lettered) opening from cylinder 3I to the passages I9 and I5. A port Hz in the central filling passage serves to connect the space H with said central filling passage 4 I.

As shown in Fig. 2, the ether vaporizer 1 screws into a re-entrant portion 3 Ia formed in the lower end of the cylinder 3|. The central filling passage 4I tapers externally at its lower end to provide a push fit interconnection with a reversely tapered sleeve Ms, carrying an extension Ma of said passage II. The sleeve 4Is also-carries a spider Mt which receives the tube I1 and an extension I'Ic of said tube, such extension being provided with a plurality of holes IId below the level of the liquid ether. The extension 4Ia is provided with apertures 4Ib spaced along its length and shielded by bafiies 4Ic. The beforementioned port I Ii in the filling passage 4| is provided with a bafiie IIg to prevent the splash of ether into the chamber portions II of the drum. The annular space Ia between the neck of the vaporizer I and the sleeve 4Is provides a passage for the gases, and openings 3Ib are provided in the horizontal cross-plate part of the re-entrant portion 3Ia above said space Ia to permit upward egress of gases from the vaporizer therethrough.

The drum I2 controlling the trichlorethylene vaporizer 9 within the cylinder 32 is provided with vertical partitions 46 (Fig. 5), dividing the annular space of the drum on the lines of a segment between a central filling passage 41 and the inner peripheral wall of the drum into two portions I2 and I2 The space portion I2 is covered by a horizontal plate 48 (indicated in Fig. 4) which supports two pairs of plate members 49 and 50 (Fig. 4), the first on the lines'of a segment and the second on lines of parallel chords, providing respectively passages 49a and 50a for the gases. The gas passage 49a opens into or from a'bent tube 9a extending down into the trichlorethylene vaporizer 9 similarly to the tube IT in the ether vaporizer I. The horizontal bottom plate of the drum I2 is provided with a port I2a adapted to register with a port I2b (Fig. 5) in the bottom plate of the cylinder 32. The circumferential wall of drum I 2 is provided with ports I2c, I2d and I2e (Fig. 4) at an upper level adapted to register with ports I21 and I2g in the walls of the cylinder 32 containing the drum, so as to lead basal gases in to the drum from the inlet passage 8 and to provide for the exit of the basal gases through the passage 8a leading to the ether drum II, while at a lowerlevel ports I2h and I22 (Fig. 5) are provided to register with the cylinder interconnecting passages 28 and I9.

The attachment 56 by which the rebreathing bag 6 is mounted at the end of the previously described passage I4 is provided with a tapered joint 56a (Fig. 3) and with a bayonet catch b to prevent accidental displacement from the passage I4. This attachment 56 is further provided with a control valve in the form of a drum 51 which can be rotated in either direction out of a mid-position. In the mid-position (Figs. 3

and 8) the bag 6 is open to the gas circuit through the port 51a in the drum 51 and a port 560 in the attachment 56. Rotation of the drum 5! in one (counterclockwise) direction closes the port 560 and opens the circuit to the atmosphere for partial rebreathing through a vent 5612 in the attachment 56 with which a smaller port 51a in the drum is brought into register (see Fig. 7). Rotation of the drum 5! in the other (clockwise) direction gradually closes both the port 560 and the vent 56d so that both the bag and the vent are closed for insuiilation.

Also, in this connection, the usual relief valve 58 is provided (Fig. 3) to prevent undue pressure from building up in the circuit.

As hereinbefore stated, it is intended that when the soda lime container 5 is open in the circuit the trichlorethylene vaporizer 9 shall not be operated; that is, it will be' rendered impossible to introduce trichlorethylene into the circuit. Accordingly, a locking device is provided between the drums IlI'and I2 in cylinders 30 and 32. This locking device as shown in Fig. 9 comprises a plunger 5| under tension of a spring 52. It is mounted in a tubular sleeve 53 extending between the two drum cylinders and is held or urged normally in engagement with a recess 54 in the drum I2, thereby keeping said drum from rotating. The drum II) controlling the soda lime container 5 also is provided with a recess 55 which, when drum I0 is moved to position cutting the soda lime container 5 out of circuit, registers with the end of the tubular ,sleeve 53. Consequently, if the drum I2 then is rotated, the cam faces 54a thereon will move the plunger 5| against the action of its spring 52 into said recess 55 of the drum III, so that drum II) will then be locked against rotationuntil the trichlorethylene drum I2 is rotated back to the ofi position. Thereupon, the spring. 52. moves the plunger 5| back intothe recess of the'drum I2, thus again locking the drum' I2 and again permitting movement of drum II).

The drum III is adapted to be moved anticlockwise through an angle of 45 from the position shown in Fig. 5. The drum II is adapted to be moved anti-clockwise through an angle of from the position shown in Fig. 5, while the drum I2 is adapted to be moved clockwise through an angle of 60. All three are turned manually by knobs, shown but not lettered, provided at the top of their respective cylinders on stem projected through the head 2|.

, In operation, with the drums II), II and 22 set as shown in Figs. 4 and 5, that is, with the soda lime container 5 in circuit and the trichlorethylene vaporizer 9 cut out of circuit, the exhaled gases from the patient (i. e., from the gas mask) enter the connection 4 to the expiratory non-return valve 2 in said connection. Past said valve the gases move through passage I3 and the port IBe into the space portion I8 of the drum III), thence down through the ports Illa and Ilia. into the space below the drum between the vertical partitions 36 and 3'! (Fig. 6). From there they pass down through the soda. lime container 5, up through the ports 50 around the annular passage between the soda lime container 5 and its casing 5a, and thence through the ports 38 into the space portion beneath the drum III enclosed by the partition 36. From the last named space the gases then pass up through the open ports Illb, Illb and down through the open ports I80, I00 into and through the passage I4 to the rebreathing bag or reservoir 6.

On inspiration, the gases traverse in reverse the path just described, with the exception that, after emerging upwardly through the ports Ito and I0a they traverse the passage 28 through ports Illj and I'Zh into the space portion I2 of the drum I2, leave said space by way of port I22 opening into passage I9 and enter the space portion II of the drum II by way of the port Ilg. The gases then pass through port Iii into the central filling passage 4| and down through its extension 4Ia, out through the apertures LlIb around the bafiies 4|c' and upwardly through the exit Ia and openings 3Ib and through ports I Ib, Ila into the space portion II of the drum II. From this last named space in drum I I the gases emergeby way-of port IIh; into the passage I5 and pass thence by way' of branch 25 to the inspiratory non-return valve I in connection 3. Thus the gases are caused to take a circulatory flow through the apparatus.

. .With the drum gIILin.theg, position shown and the drum I2 locked against movement as illustrated in Fig. 9,-the drum; Iizmay be -rotatedzin. an anti-clockwise direction through 90 togits. off position. As the drum I: I.-,$lS'iSO rotated. thc-- partition 48: gradually. movestlacross the opening from the passage i9wintoicylindeir-3l aand.,,accordingly, the gases in the: patients-- circuitiol lowing the flow above: described will: alteinal ll enter both the space-portions I I and I I Those of the gases whichenterthezz portion H arepassedjdown aspreviously described through port- I I2 and the filling. passage 14Iethroughithegvapor izer I, and return througntheybut now only.v partially open ports;- I In and; I Ib 'intqiithe space portion II Those of said'gaseszwhich altere natively now" initially enter said space p ortion I i from the passage-Illnpass directly;across the top of the vaporizerr'I and join the reduced flowcoming up therefrom through. the. ports I Ia and. III). Together they, pass out through-port IIh into thepassage. I and. thence- ,to thednspira tory non-return valve I by way;ofthe branch ersing or entering downinto" the. ethervaporizer "I.

Further, with thedrums it, II and I2 in the positions shown, i. e., with the soda lime drum It turned on, the trichlorethylene drum I2 turned oil and the ether drum; II turned on, the

basal gases, if flow of the latter is turned on, will enter through the passage 8 lFig. 4), pass through the ports I2f,;I2c into the gas passage a of the drum I2 and leave'the last-named passage by way of ports IZe, I2g at the opposite side of said drum. These basal gases are conducted thence by the passage 80. (Figs. 4. and 2) to the drum II, entering the latter throughports He, He into the space passage 44a. thereof and pass on down through thetube I'I extending therefrom into the vaporizer I. Emerging through the apertures I'Idand bottom of said tube, these gases mingle and rise with the gases in the patients circuit which are flowing, as previously described, down into the vaporizer through the passage M. The basal gases thus admixed with the gases in the patients circuit then enter therewith into the portion H of the drum I I through the ports I Ia, I lb and leave the drum by way of the port IIh, passing onward through the passage I5 and branch 29 which lead to the inspiratory non-return valve I in connection 3.

If the drum I I now is rotated in anti-clockwise direction from its on position towards its off" position, the basal gas flow entering through port I Ie from the passage 8a isv divided between the gas passages 44a and 43a'of the drum, that portion of such flow which is directed into passageMa being led through the vaporizer I as already described above, while that portion of the flow which is diverted into passage 43a is led straight/to the outlet passage 45 by Way of the ports II and lid. Hence, the diverted portionis led'direct -to the inspiratory valve in the connection 3. Naturally, in the full off position. of said'drum, all of the basal gas flow will be diverted-across the top of the ether vaporizer 1 into -the passage 45 without traversing. oripassingdown, into said vaporizer.

If thedrum I0 is rotated anti-clockwise through:- 45 from the on position shown in Fig. .5rto its. on position, the space portion lll 'of said=drum1 will no longer be in communication throughport. Ifle. with the passage I3 from the expiratory valve: Instead, the space. portion I0 will. be brought into communication with. said: passage and valve through the port. lflh. Also,-. due-to the rotation of the drum, the ports I Ila, Illb', and -I 00 will no longer be in register-with the ports: Instead, the 'port Illd' will in connection 4.

Illa}, "lb and iec now be brought into register with the port IlIdl.

Hence, in such off position of the:drum; withthe gases in the patients circuit now entering.: q space portion I0 from the expiratorynon-ree turn valve 2,-and with the ports I02) and We now closed, the only port left open from said space.

portion I0 will bethe port Illgj which DOWTBQIS'? ters-with passage I5. Consequently, on expiration, the gases now'will traverse this passage Iii and enter the space portion I I of drum II, thenpass down through the ports. I la, IIb and enter: the ether vaporizer 'I through the openings :3Ib. and passage Ia. From the vaporizer the gases:

pass'back upward by way of the central filling passagel and port IIi into the space portion II of the drum I I. From this space they move then through the port Iig, passage I9 and port I22 into, the space portion I2 of the drum I2, thence 1 through port IZh, passage 28 and port IIlf into theyspace portion I3 of the drum-I0. Thus circulated back to the drum III, the gases now pass down through the ports Ind, Illd to the passage; I4 and rebreathing bag or reservoir 6. On-in-.

spiration, the gases flow back from the rebreathing-,bagor reservoir 6 in the reverse direction to.-

withdrawn through branch 29 tothe inspiratory? non-return valve I of connection-3.

When the drum In is in off position and the soda lime container 5 is out of circuit, as just above described, the drum- I2 controlling the-trichlorethylene vaporizer 9 may be rotated; therebytlocking said drum III in the ofi? position by engagement of the plunger 5| in the recess 55 aspreviously described. If the drum I2 is rotated to its on position, in'which the port In registers with the port I2b, the gases in the pa-- tien-ts circuit will still follow the path hereinabove described, since the port I21 will. still register with thepassage I9 and the port I2h will still register with the passage 28, i. e., said gases do not traverse or enter into the trichlorethylene vaporizer 9. On-the other hand, the basal gases, instead of entering passage 50a through ports I2 as previously described, will now enter passage 4911 through ports I2 I2d. Accordingly, the basal gases are led down through the bent tube-9a into the trichlorethylene vaporizer 9 and out again by wayof the ports I2, I21), passing over the top of the covered passage 50a (formed by the plate members 56) and leaving the-drum I2 by way of ports IZh, I2g. Thence, the'basal gases traverse the passage 8a to the drum II and, depending upon the setting of this last named drum'in 01f position, on position, or an intermediate positiontherebetween, the basal gases are passed either through the passage. 44a, into the ether vaporizer, or through the passage 53a to direct exit through port I Id and passage 45, or partly through both.

Although, throughout the above description, reference is made to a trichlorethylene vaporizer;

it is to be understood that this could be replaced by a chloroform vaporizer.

I claim:

1. Apparatus for the administration of inhalent gas mixtures for anethetizing purposes,

- comprising, for use with a face-mask applicable to the patient; a patients circuit including inspiratory and expiratory valves having connections for said mask, a vaporizer for a volatile liquid to be administered to the patient in a gaseous state, a carbon dioxide absorber, passages connecting the vaporizer and absorber and each with said inspiratory and expiratory valves, arebreathing bag operatively connected by the passages connecting said vaporizer with said absorber and each with the two named valves, and control valves arranged in the several interconnecting passages for controlling the flow of gases therein between the vaporizer and absorber and between the respective first-named two valves; a basal gas circuit connected with said patients circuit and including a second vaporizer for a second volatile liquid to be administered to the patient in a gaseous state, control valves in said basal circuit for controlling the flow of basal gas from its supply source into the patients circuit and either through or past the second vaporizer, together with a flow meter for determining the volume of basal gas supply feed from its source; and mean preventing admission of any of the basal gas into said secondvaporizer before entry into the patients circuit while the absorber of said patients circuit is open therein to circulatory flow operation; the component elements of the two defined circuits being as-. sembled in compacted close relationship to form a small portable unit in which the flow meter, the inspiratory and expiratory valves, and the rebreathing bag are visible together from a position in which all said valves are also opera-. 3

ble by the administrator.

2. Apparatus for the administration of inhalent gases as claimed in claim 1, wherein a single control is provided for the valves controlling the fiow of gas in the patients circuit between the expiratory valve, the carbon dioxide absorber, the rebreathing bag and the vaporizer of said circuit.

3. Apparatus for the administration of in-- halent gases as claimed in claim 1, wherein a valve is provided at the point of the basal gas circuits connection with the patients circuit for delivering the gas supplied by the former to the latter to the inspiratory valve of the latter alternatively either direct or by way of the vaporizer of said latter circuit. r

4. Apparatus for the administration of inhalent gases as claimed in claim'l, wherein a valve is provided at the point of the basal gas circuits connection with the patients circuit for directing the gas introduced by the former into the latter to the inspiratory valve of the latter alternatively either direct or by way of the vaporizer of said latter circuit, and said directional control valve also controls the relative flow of gas within the patients circuit and gas from said basal gas circuit to said inspiratory valve.

5. Apparatus for the administration of inhalent gases as claimed in claim 1, wherein a valve is provided at the point of the basal gas circuits connection with the patients circuit for directing the gas introduced by the former into the latter to the inspiratory valve of the latter alternatively either direct or by way of the vapor- 10 izer of said latter circuit, and said directional control valve also controls the relative flow of gas within the patients circuit and gas from said basal gas circuit to said inspiratory valve;

said control valve being in the form of a rotary ported drum the progressive rotation of which results in progressive increase of flow of patients gas and basal gas to said inspiratory valve, the flow of patients gas reaching a maximum rate before the flowof basal gas reaches its maximum rate.

6. Apparatus for the administration of inhalent gases as claimed in claim 1, wherein a single control is provided for the valves controlling the flow of gas in the patients circuit between the expiratory valve, the carbon dioxide absorber, the rebreathing bag and the vaporizer of said circuit, the valves controlling flow to and from said absorber being capable ofcutting the absorber entirely out of circuit operation.

7. Apparatus for the administration of inhalent gas mixtures for anesthetizing purposes, comprising, for use with a face mask applicable to the patient; a patients circuit including inspiratory and expiratory valves having connection for said mask, a vaporizer for a volatile liquid to be administered to the patient in a gaseous state, a carbon dioxide absorber, passages connecting the vaporizer and absorber each with said inspiratory and expiratory valves and with each other, a rebreathing bag, operatively connected with the passages connecting said vaporizer and absorber each with said two named valves and with each other, and control valve elements for controlling the flow of gases through said interconnecting passages between and to and from the absorber, rebreathing bag and vaporizer for varying the circulatory path thereof as desired between the expiratory and inspiratory valves; a basal gas circuit connected thereof and including a second vaporizer for a second volatile liquid to be administered to the patient in a gaseous state, together with a source of basal gas supply and a flow meter for indicating the volume of supply thereinto, and control valve elements for controlling the flow of the basal gas between its source and point of entry into the patients circuit either past or through or partially past and through the second vaporizer} said control valve elements of the patients circuit consisting of single rotatable drum members mounted one each over the absorber and the vaporizer of said circuit and having ports therein arranged respectively to register with the passages to and from the said members they overlie and to move out of register or to register in difierent relations with said passages as they are rotated to difierent positions so as to open and close oropen to alternate permission of flow the passages between said members, and the said control valve elements of the basal circuit consisting of a third rotatable drum member mounted over the vaporizer of the latter circuit and having ports therein arranged to register with passages of the circuit to and from the said member it overlies and to move to register in different relation with said passages as it is rotated to different, positions so as either to direct the basal gas supply from its source direct to the point of entry into the patients circuitin bypass of said vaporizer oralternately to pass said gas supply first into and through said vaporizer or partially in both paths of flow.

8. Apparatus "for 'the administration of inhalent gas mixtures for anesthetizing purposes,

comprising, for use with a face mask applicable to the patient; a patients,circuit/including in spiratory and expiratory valves having .connec-" tion for said mask, a vaporizer for a volatile liquid to be administered to the patient in a gaseous state, a carbon dioxide absorber, passages connecting the vaporizer and absorber each with said inspiratory and expiratory valves and with each other, a rebreathing bag operatively connected with the passages connecting said vaporizer and absorber each with said two named valves and with each other, and control valve elements for controlling the flow of gases through said interconnecting passages between and to and from the absorber, rebreathingibag and vaporizer.for varying the circulatorypath thereof as desired between the expiratory and inspiratory valves; a basal gas circuit connected with said patients circuit at a point of passage between the vaporizer and the inspiratory valve thereof and including a second vaporizer for a second volatile liquid to be administered to the patient in a gaseous state, together with a source of basal gas supply and a flow meter for indicating the volume of supply thereinto, and control valve elementsfor controlling the flow of the basal gas between its source and point of entry into the patients circuit either .past .or through or partially past and through the second vaporizer; said control valve elements of the patients circuit consisting of single rotatable drum members mounted one each over the absorber and the vaporizer of said, circuit and having ports therein arranged respectively to register with the, passages to and from the said membersjthey overlie and to move outcof register or to register in different relations with said passages as they iarerotated to different positions sodas ltolopen and close or open to alternate permission of flow the passages between said members, and the said control valve elementsof the basal circuit consisting of athird rotatable drumimember'mounted over the vaporizer of-the latter circuit and having ports therein arranged to register with passages of the cir ccuit to and from the said member it overlies :andto move to register in different relation with said. passages as it is rotated to different positionsso as either to direct the basal gas supply from its source direct to the point'of entry into the ,patientfs circuit in bypass of said vaporizer or alternatelyto pass said gas supply first into and through said vaporizer or partially in both paths offlow: and means provided between said third rotatable drum member and the. rotatable drum member mounted over the absorber of the patients circuit for locking said third drum member in position bypassing the basal gas flow over the vaporizer of the basal gas circuit while the rotatable drum member over ,said absorber 15 in position permitting circulation of gases in the patients circuit through said absorber.

9. Apparatus for the administration of inhalent gas mixtures for anesthetizing purposes,

connected with the "passages connecting said vaporizer and absorber each withsaid two named valves and with each other, and control valve elements for controlling the flow of gases through said interconnecting passages between and to between the vaporizer and-the inspiratory valve thereof and including a second vaporizer for a second volatile liquid to be administered to the patient in a gaseous state, together with a source of basal gas supply and a flow meter for indicating the volume of supply thereinto, and control valve elements for controlling the flow of the basal gas between its source and point "of entry into the patients circuit either past or through or partially past and through the second vaporizer; said control valve elements of the patients circuit consisting of single rotatable drum members mounted one each overthe absorber and the vaporizer of said circuit and having ports therein arranged respectively to register with the passages to and from the said members-they overlie and to move out of register ortoregister in different relations with said passages as they are rotated to diiierent positions so as to open and close or open to alternate permission of flow the passages between said members, and the said control valve elements of the basal circuit consisting of a third :rotatable drum "member mounted over the vaporizer of the latter circuit and having ports thereinarranged'to register with passages of the circuit to and'from the-s'aid member it overlies and to move 'toregister in different relation with said passagesasiit is-rotatedto difierent positions rotatable drum member and the rotatable drum =member mounted over the absorber of the patients circuit for locking said third drum member in position by-passing the basal gas flow over thevaporizerof the basal gas circuit while the rotatable drum member over said absorber is in position permitting circulation of gases in the patients circuit through said absorber; the component elements of the two defined circuits being assembled in close relationship to form a compact unit in which the flow meter, the inspiratory and expiratory valves, and the 'rebreathing bag are visible together from a position in which the three rotatable drum members providing the control valve elements are also operable by the administrator.

10. Apparatus for the administration of inhalent gas mixtures for anesthetizing purposes, comprising, for use with a face mask applicable to the patient; a patients circuit including inspiratory and expiratory valves having connection for said mask, a vaporizer for a volatile liquid to .be administered to the patient in a gaseous state, a .carbon dioxide absorber, passages connecting the vaporizer and absorber each with said 'inspiratory and expiratory valves and with each other, a rebreathing bag operatively connected with the passages connecting said vaporizer and absorber each with said two named 1 valves ancl'with each other, and control valve 13 elements for controlling the fiow of gases through said interconnecting passages between and to and from the absorber, rebreathing bag and vaporizer for varying the circulatory path thereof as desired between the expiratory and inspiratory valves; a basal gas circuit connected with said patients circuit by opening into an extra passage between the vaporizer and the inspiratory valve thereof and including a second vaporizer for a second volatile liquid to be administered to the patient in a gaseous state, together with a source of basal gas supply and a flow meter for indicating the volume of supply therein, control valve elements for controlling the flow of the basal gas between its source and the point of entry into the patients circuit either past or through or partially past and through the second vaporizer, and separate control valve elements at the point of basal gas entry into the patients circuit for controlling the introductory movement thereof either directly to the inspiratory valve or indirectly thereto through the vaporizer of the patients circuit or partially along both paths; said control valve elements of the patients circuit consisting of single rotatable drum members mounted one each over the absorber and the vaporizer of said circuit and having ports therein arranged respectively to register with the passages to and from the said members they overlie and to move out of register or to register in difierent relations with said passages as they are rotated to diiferent positions so as to open and close or open to alternate flows the passages between said members, the rotatable drum member mounted over the vaporizer of said patients circuit including also the separate control valve elements for controlling the directional flow of the basal gas introduced into the patients circuit, and the said control valve elements of the basal circuit consisting of a third rotatable drum member mounted over the vaporizer of the latter circuit and having ports therein arranged to register with passages of the circuit to and from the said member it overlies and to move to register in different relations with said passages as it is rotated to difierent positions so as to direct the basal gas supply from its source either direct to, the point of entry into the patients circuit in by-pass of said vaporizer or alternately to pass said gas supply first into and I through said vaporizer or partially in both such paths of flow.

11. Apparatus for the administration of inhalent gas mixtures, comprising a regulatory gas flow circuit including in combination; a vaporizer for a volatile liquid to be administered to the patient in a gaseous state; patients inspiratory and expiratory valves having connections for a mask applicable to the patient; a carbon dioxide absorber; passages connecting the inspiratory valve with said absorber and the expiratory valve with said vaporizer and the absorber and vaporizer together; a rebreathing bag operatively connected by the passages connecting said vaporizer to said absorber and the two stated valves; other valves in the circuit for controlling the flow of gases therein between the respective first-named valves, absorber, rebreathing bag and vaporizer each with the other; a correlated basal gas circuit including a second vaporizer for a second volatile liquid to be administered to the patient in the gaseous state; a metering valve connected to a source of basal gas and to said second vaporizer in the basal circuit; a flow member operatively connected to said metering valve; and a passage connecting both said second vaporizer and said metering valve to the first defined flow circuit; the several elements of the first defined and the basal gas circuits being assembled in close relationship to form a compact portable unit in which the fiow meter, the inspiratory and expiratory valves, and the rebreathing bag are visible together from a position in which all said valves are also operable by the administrator.

12. Apparatus for the administration of inhalent gases as claimed in claim 11, wherein the vaporizer of the regulatory flow circuit receiving gases exhaled by the patient through the expiratory valve and delivering gases inhaled by the patient through the inspiratory valve includes tubes arranged one within the other providing passages for gas entry thereinto and withdrawal therefrom; said tubes extending downwardly within the vaporizer to a level below the normal level of the volatile liquid contained therein to be volatilized into enriching admixture with the gases passed therethrough.

13. Apparatus for the administration of inhalent gases as claimed in claim 11, wherein the carbon dioxide absorber of the regulatory flow circuit through which gases exhaled and inhaled by the patient are passed for removal of carbon dioxide contained therein comprises a vessel housed in a fixed casing having a readily detachable closure at its lower end serving as a support for the vessel, resilient means being provided between said casing closure and said vessel to maintain the vessel tight at its upper end against an abutment around its communicative opening to the gas circuit, and a sealing ring between said upper end of the vessel and its said abutment to render it airtight exteriorly around such opening.

HENRY REX MARRETT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,897,378 Hinkle Feb. 14, 1933 1,971,408 Heidbrink Aug. 28, 1934 2,407,221 Bloomheart Sept. 10, 1946

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