US2774347A - Apparatus for producing artificial respiration - Google Patents

Description

Dec. 18, 1956 J. H. EMERSON APPARATUS FOR PRODUCING ARTIFICIAL RESPIRATION 4 Sheets-Sheet 1 Filed March 17, 1954 M 2 16 M v. ma m v 9 m 1 WI 2 .L/9 23 KB M m 45 Jul/en i29 Jakn .ZZ-Emerson; AA, W

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Dec. 18, 1956 J. H. EMERSON 2,774,347

APPARATUS FOR PRODUCING ARTIFICIAL RESPIRATION Filed March 17, 1954 4 Sheets-Sheet 2 '60 Inventor, zfoizn H Emerson 5 A414,, M k 6 I Atiys.

Dec. 18, 1956 .1. H. EMERSON APPARATUS FOR PRODUCING ARTIFICIAL RESPIRATION 4 Sheets-Sheet 4 Filed March 17, 1954 w Inventor; ci'okn ff E77ZFS07Z M, M

United States Patent APPARATUS For: rnonncmo ARTIFICIAL nnsrmArroN John H. Emerson, Arlington, Mass.

Application March 17, 1954, Serial No. 416,858

24 Claims. 01. 128-30) This invention relates to apparatus for producing artificial respiration in a patient and more particularly to the types of artificial respirators where the patents chest and/or abdomen, and/ or nose and/ or mouth are enclosed in a casing and are subjected to alternating periods of two different pressures, such as negative and substantially atmospheric or positive pressures, to assist him to breathe.

One object of the invention is to provide such an apparatus in which the time of each of said alternating pressure periods is pneumatically controlled by a pneumatic system which is operated by variations of pressure different from, but variable with, pressure variations within the respirator casing.

Another object is to provide such an apparatus wherein the interior of said casing is quickly brought to the desired pressure after the initiation of each of said alternating pressure time periods, the desired pressure being maintained in the interior of the casing during the major portionot' each of said periods.

Yet another object is to provide an artificialrespirator in which the alternating pressure periods are controlled by variation of pressure in a control chamber separated from the main pneumatic system of said artificial respirator by a restricted passage, the timeof at least one of said periods being controlled .by controlling the size of said restricted-passage.

Yet another object of the invention is to ,provide .an artificial respirator wherein the relative times :of the inhalation and exhalation .periods may be controlled and adjusted.

Yet another object of the invention is to provide artificial respirator with a novel pneumatic cont'rol.

Yetanother object of the .present invention .-is 'toprovidea valveapparatus for cyclicallylproducing alternating pressures of different-magnitude.

Other objects of the invention are 'to provide an artitficial respirator of the character described which is of :simple, compact and durable construction, which is :accurate and dependable in use and which is economical to manufacture and to maintain in operation.

)ther and further objects and advantages of the invention will be pointed out in the following description {and .by reference to the accompanying drawings wherein:

Fig. 1 is a side elevation of one-form of respiratorfwith avhichthe invention'm'ay'beutilized;

Fig. 2 is aschematic vie'wbf one embodiment o f the invention, wherein the cycling of the device 'for creating variations in pressure is controlled by a pneumatic :system which is operated primarily by variations of pressure 'within'the casing. i g

Fig. 3 is a schematicvi'ew -of another embodiment "of ihein'vention, where'in'the cycling of the deviceifor'creating'variations in pressure is controlled by a pneumatic system whichis operated primarily by variationsof"-pjres- :sure withinthecasing.

Fig. 4 shows partly inside e levat'ion-'and partly-in vertical section yet another e'nibodiment of "the present invention during a negative" pressure period, wherein a chest type respirator is utilized.

2,774,347 Patented Dec. 18, 1956 ice Fig. 5 is an enlarged vertical section of the time cycle control mechanism of Fig. 4 during a positive or atmospheric pressure period, with a small portion thereof shown in side elevation and another portion cut away.

Fig. 6 is a top plan view of the time cycle control apparatus-of Fig, 4.

Fig. 7 is a side elevation of the time cycle control apparatus of Fig. 4 during a negative pressure cycle, with a portion of chamber 68, a portion of support 66, and connecting members 74 and 72 broken away and with additional springs 108 added thereto.

Fig. 8 is adiagrammatic side elevation of yet another embodiment of the time cycle control mechanism of the present invention.

Fig. 9 is a diagrammatic bottom viewof the mechanism :of Fig. 8 during a negative pressure period.

Fig. 10 is a view similar to that of Fig. 9 during a positive pressure period.

Referring to Figs. 1 and 2, the respirator is here shown by way :of example as comprising the usual-substantially air-tight respirator casing 1 which forms an enclosure for the patients body up to his neck. The patient reclines @upon a horizontal bed (not shown) within the casing and his neck extends through a restricted orifice in a collar of sponge rubber material (not shown) at the end 4 -of=the casing, his head resting upon the head rest 5 and exposed to the atmosphere. It is to be understood, how- :ever, that the enclosure for the patients chest may comprise a conventional chest respirator, as shown in Fig. 4, wherein the substantially air-tight casing forms *an enclosure -for at least part of the patients chest. Such a respirator sometimes encloses the entire-chest and some- -tim eslpart'ofthe chest and part of the abdomen.

'Beneath the opposite end of the respirator a compartent 6 (Fig. l) -is provided in which is disposed an apparatus schematically shown in Fig. 2 and which Zincludes a negative pressure conduit 10 communicating :at one :end with the interior of the respirator casing :through the delivery conduit means 100. At the opposite end 1 1 of the conduit 10, a motor operated suction :lblower .12 of any desired construction is provided for continuously creating negative pressure within the negative pressure conduit 10. Atmospheric conduit 13 communicates with the delivery conduit I00 and thus with the interior of the casing 1 and with the atmosphere :through the port 121. The exhaust tube 15 of blower 12 communicates with the atmosphere. An electrically operated butterfly 'valve 18 is provided in the atmospheric conduit 13. This valve 18 is normally maintained in closed position by a spring (not shown) The valve 18 is opened by suitable means here shown :a'sia solenoid 20A which is energized by a circuit to open the valve (as shown in Fig. 2) as will hereinafter be described, and closed by said spring (not shown) upon deenergizationof said solenoid although it is to beunderstood :that any suitable electrically operated means such as a double acting solenoid, two motors or one electrically reversing motor, may be used to operate this valve.

When the valve 18 is closed, the suction blower 12 creates negative pressure in the negative pressure conduit 10, in delivery conduit and in the "respirator casing 1 and this negative pressure causes expansion of the patients chest and lungs and thus causes an inhalati'on. 'Wlren'the valve 18 is opened, air is drawn into port 121 through conduit 13 and conduit 100 into casing 1 thereby neutralizing the negative pressure'in 'the'ca'sing and building up the pressure therein to atmospheric pressure. This variation in pressure acts upon the .pa tients chest and creates a forced exhalation.

The negative pressure conduit 10 is provided withjan atmospheric "gas inlet port 21 providing communication between the atmosphere and the interior of the negative by a suitable valve 22 here shown, for example, as comprising a cylindrical casing 23 having a central bore 24, the inner end of the casing constituting a valve seat 25. A disc 26 constituting a valve is shown in seated position and is resiliently urged outwardly to seated position by means of a helical spring 27 having its inner end in contact with the outer end of the casing 23 and its-outer end engaging the knurled nut 28 which is adjustable longitudinally of the threaded stem 29, one end of which is fast to the disc. This is a negative pressure adjusting valve and it opens only .when the negative pressure within 8 the conduit exceeds a'predetermined amount, in which event the valve 26 is moved'inwardly compressing the spring and admitting gas under atmospheric pressure to the conduit 10, thereby decreasing the amount of negative pressure in the conduit until the spring returns the valve to its normal seated position; v v

The pneumatically operated switch 123 is mounted in a housing 122; The switch itself is mounted in the compartment 124 which is in continuous communication with the atmosphere through the port 125. ,The diaphragm 126 is'securedr at its periphery to the housing 122 and the diaphragm, may be made .of rubberized fabric. .The switch arm 127 is mounted for pivotal movement about the axis 119, and it is normally maintained in the lowered position shown in Fig. 2 by the spring pressed plunger 128 which also actuates thermovable contact (not shown) of the switch 123. The lower end of the wire loop .129. is secured about the free end of the arm 127 and its upper end is secured to the center of the diaphragm 126. The compression spring 130 tends to'maintain the diaphragm 126 in its normal or downward position as illustrated in Fig. 2, the amount of pressure exerted by said. spring upon the diaphragm being controllable by the thumb screw 131. The chamber 132 provided between the diaphragm 126 and the housing 122 is substantially air-tight.

A transfer conduit 129 provides communication beclosed by the substantially atmospheric pressure in the.

transfer circuit and the needle valve 136 which continuously admits a small amount of air under atmospheric tween the interior of the respirator casing 1 (to which the 1 end of the conduit 100 is connected) and the interior of the chamber 132. Check valve 134 in conduit 120 is normally closed but is opened by the creation of negative pressure in the transfer conduit 120 and is automatically I closed when the pressure in the transfer conduit 120.is

returned to at least substantially atmospheric pressure. Valve 135 incond'uitlZll may be a needle valve or any other means for controlling the effective size of the passage in the transfer conduit 120. The valve 136 is a needle valve by means of which effective size of the passage 137 is controlled, said passage aifording communication between the interior of the chamber 132 and the atmosphere.

With the butterfly valve 18 in closed position, the negative pressure creating means 12 creates negative pressure in the'respirator casing 1, causing a period of inhalation by the patient. At the same time negative pressure is created in the transfer conduit 120. The negative pressure in the transfer conduit opens the valve 134 and because. of the restricted size of the passage of the transfer conduit at the needle valve 135, the amount Olf negative pressure is gradually built up in the valve chamber 132. Eventually itbui'lds up sufiiciently in the valve chamber 132 so that the diaphragm 126 is elevated sufiiciently for .the'arm 127 to move the plunger 128 upwardly a sufficrent :distance to close the contacts of the switch 123.

This closes. the circuit L1, 140, 123, 141, 20A, 142 and V 7 L2, whereby solenoid 20A is energized and rotates the valve 18 to opened position.

i Opening the valve 18 admits air under atmospheric pressure through the port 121, conduit 13, conduit 100 to the respirator casing 1 and this air substantially neutralizes' the negative pressure which had theretofore been built up in the casing while the valve 18 was closed. The

negatiVeQpressuIe in the transfer conduit 120 is correv spondinglyneutra'lined, .the valve134 is automatically air which had previously been admitted to the respirator casing through the port 121 and conduit 13 and commencingthe next period of negative pressure in the respirator casing.

From the foregoing description, it is apparent that the pneumatic system illustrated in Fig. '2 operates automatically to produce a predetermined period of negative pressure within the respirator casing and a predetermined period of substantially atmospheric pressure therein. During the period of negative pressure the patients chest and lungs are expanded and he is forced to inhale. During the period of substantially atmospheric pressure the previously created negative pressure within the casing is neutralized and the pressure therein is returned to substantially atmospheric, thus causing the patients chest and lungs to collapse and forcing him to exhale.

The duration of the period of negative pressure may be adjusted by opening or closing the needle valve 135. When the effective size of the transfer conduit is reduced it takes a longer period of time to build up sufli-.

cient negative pressure in the valve chamber 132 to move the diaphragmupwardly and consequently the'duration of the period of negative pressure is increased. By open ing the valve the duration of the period of negatrve pressure is decreased.

By adjusting the needle valve .136 towards closed position, air is admitted from the atmosphere at a slower rate to the valve chamber 132 and consequently it takes a longer period of time for the negative pressure created in the valve chamber 132 during inhalation to be The embodiment of Fig. 3

In the embodiment illustrated in Fig. 3 of the drawings, as in the case of the embodiment of Fig. 2, the

pneumatically operated switch is operated by variations torycasing through the delivery conduit means l00 and .at its opposite end 11 with the motor operated suction blower 12. The negative pressure safetyvalve 22 is of the same construction as that illustrated in Fig. 2 of the drawings. The atmospheric conduit 13 communicates with the conduit 100 and thus withvthe interior of the respirator casing 1 and with the atmosphere through the port 14. The exhaust tube 15, of the suction blower 12 extends into the atmosphere conduit 13 audit is procamps-z i .vid'ed at the. endiadjacentito the port .14 with aw-venttiri 2L7 havinga restricted orifice.

' The butterfly :valve 118 located in the atmospheric con duit 13 is operated by the double acting :solenoid 20B.

'Fl'he doubleacting solenoid 20B .is energized by one circuit to -move the valve to closed position and by anothercircuit tomove the valve to open position. .As in ;the other embodiment, any suitable :electrically :operated means imay be substituted for the solenoid 32013.

The double acting switch 152 is .mounted in the'housing 122 and is located in the lower chamber .124 there of. Theaport 125 affords continuous'communication'between the interior. of the chamber l24 and=the atmosphere.

The diaphragm 126, made of rubberized fabric or other suit-able flexible material, has its edge secured -to the housing '122 and it forms one wall of the substantially air-tight chamber :132.

The switch arm 153 is-mount'edzfor pivotal movement abo'utthe axis 160 and his normally retained in the position illustratedin Fig. 3 bythe permanent magnet 156. When it .is in said position one of the circuits hereafter described is closed by the spring pressed plunger 154. When the switch arm is moved upwardly a sufficien't distance about the axis 160 the spring pressed plunger 154 :18 elevated by the spring (not shown) andthisaction opens the first mentioned circuit and closes another circuit.

The arm '153 is elevated about its pivotal connection by the wire 151, the lower end of which is secured about the switch arm 153 and the upper end of which is attached .to the center of the diaphragm 126.

When sufficient negative pressure is created in the chamber '132, said negative pressure acts upon the center of the diaphragm '126 and moves 'it upwardly :azsufficient distance so that the lower end of the wire "151 elevates the free end of the switch arm 153 and it snaps away from the magnet 156, thus permitting the plunger 154 to move upwardly following the arm.

When the ne ative pressure in the chamber 132 is net!- tralized to substantially atmospheric pressure or to positive pressure, the diaphragm 126 returns to the normal position illustrated in Fig. 3 and the arm 153 is moved downwardly into contact with the upper surface of the magnet 156. This action correspondingly depresses the plunger 154 and causes another circuit to be energized as more fully described hereafter.

The interior of the chamber 132 is connected to the interior of the respirator casing '1 by the transfer conduit 150, one end of which communicates with the top of the valve chamber 132 and the other end of which is provided with a slight flared portion 162 which, in the embodiment illustrated, is located in the atmospheric conduit '13 so that it may more readily receive atmospheric and positive pressure created in the atmosphere conduit.

The transfer conduit 150 is provided with a negative pressure by-pass conduit 165 and an atmospheric bypass conduit 17%. The check valve 166 in the negative pressure by-pass conduit is normally closed but it is opened by the creation of negative pressure in the negative pressure by-pass 165 and it is automatically closed when the pressure in said by-pass is returned to at least substantially atmospheric pressure. The valve 167 located in the negative pressure by-pass may be a needle valve or any other means for controlling the effective size of the passage in the negative pressure by-pass.

The check valve 171 is opened by the creation of substantially atmospheric or positive pressure in the atmospheric conduit 170 and is closed by negative pressure therein. The valve 172 in the atmospheric by-pass may be a needle valve or any other means for controlling the effective size of the passage in the atmospheric by-pass 170.

The valve 175 located in the transfer conduit 150 may f6 ;be;-a:needle avalvezor any other :means for controlling the effective :size 10f :the passage in the transfer conduit.

The iconduit 100 .is .providedwith an :outlet portal) providing communication between :the atmosphere :and the interior 'ofithis conduit, the outflow ofair being controlled by ,a suitable valve .here shown by way of 'example 'as a valve 32 which ismoved to closed position by,negativepressurewithin the conduit but which opens to an adjustable predetermined extent determined by the position of the regulating screw 33 supported by the plate 34 when thelpressure of theair within the conduit reaches substantially atmospheric pressure. Accordingly, ithis :valve functions as a leak for positive pressure andzbyadjustin'g the amount it can open, the sizeof the leak is controlled and the maximum positive pressure which can be created'in the casing is likewise controlled.

With the butterfly valve 18in closed position, the negative pressure creating means '12 creates negative pressure in "the respirator casing, causing a period of inhalation by the patient. At the same time, negative pressure is created in :the transfer conduit 159 and in the by-pass conduits 165 and 170. The negative pressure in the atmospheric-bypass 1 -cl0sesthe check valve 171'whereas the negative pressure in the negative pressure by-pass 165 opens the check valve 166 so that negative pressure is transmitted tothe chamber 132 of the pneumatic switch element.

Eventually suliicient negative pressure is built "up in the chamber132to elevate the center of the diaphragm 1 26, the outer end of the switch .arm 153 and the contact plunger 154. The amount of time required to build up the required amount of negative pressure in the chamber 132 depends upon the adjustment of the needle valve 167.

When theswitch arm 153 is thus elevated by the diaphragm 126, the circuit Ill, 1st, 152, 181,20B,182 and 1:2 is energized-and the double acting solenoid 20]?- opens the bu'tterfiy valve '18. This terminates the period at inhalation by the patient and permits air under positive pressure to flow from the venturi 17 and port 14 through the atmospheric conduit 13 and the conduit to the interior of the respirator casing 1, thus neutralizing the negativepressure previously built up therein and returning-it to atmospheric or positive pressure.

Opening of the valve 18 also causes air under positive pressure to enterthe transfer conduit and to neutralize the negative pressure theretofore present therein. This air under positive pressure closes the check valve 166 and opens the check valve 171 and it passes through the atmospheric by-pass and thence to the valve chamber 132 of the pneumatically operated switch. Eventually it neutralizes the negative pressure previously built up in the chamber 132 and the pressure therein becomes substantially positive. The center of the diaphragm 126' then is returned to its lowered position and the wire 151 moves the free end of the switch arm 153 downwardly to the position shown in Fig. 3. The amount of time required for this operation depends upon the adjustment of the needle valve 171 since said valve controls the rate of flow of gas through the conduit 179.

When the switch arm 153 has been returned to its lowered position, the contact plunger 154 is lowered, the circuit previously energized is opened and the circuit 111, 130, 152, 185, 2013, 182 and n2 is closed. This causes the solenoid 2GB to rotate the butterfly valve 18 to closed position. This shuts ofi the supply of positive pressure in the atmospheric conduit 13 andcauses the exhaust from the ven'turi 17 to be vented to the atmosphere through the port 14. Negative pressure is now built up in the respirator casing 1 'by the suction blower 12, the

that the needle valves 167 and 172 maybe manipulated to provide a "longer period of inhalation than of eXhala'-- tion or vice vers'a. 1

The needlevalve 175 located in'the transfer conduit 150 may be used to adjust theduration of the combined periods of exhalation and of inhalation. When' the needle valve 175*isradjusted5 toward closed position, gas passes through the transfer conduit 150 at a smaller volume per unit of time and consequently the duration of'the combined periods of exhalation and inhalation is increased. Conversely, when the valve 175 is adjusted toward open position, the duration of the combined periods of exhalation and inhalation is decreased because gas passes through the transfer conduit in greater volume during a given period of time;

From'the foregoing description, it will be'understood as in the embodiment disclosed in Fig. 2. v

' The embodiment of Figs. 4, 5, 6 and 7 This embodiment provides a portable valve apparatus 50, capable of being connected to the vacuum tube of any ordinary vacuum cleaner or any other means for pro-. ducing a vacuum and shown in Fig.4 attached to chest respirator 51 on patient 52. Chest respirator 51 may be of any known type. 7

Such portable apparatus can be utilized with larger respirators of the type shown in Fig. 1 as well as chest respirators as shown. In such case, the delivery conduit means 75 is connected with the interior of the respirator casingl of Fig. 1.

Portable valve apparatus 50 is mounted on a platform 53 having felt or foam rubber pads 54 attached to the bottom thereof. Also mounted on platform 53 isa conventional voltage regulator 55 having a switch 56, a control knob 57, a power line 58 adapted to be connected to any household electrical socket, and an electrical receptacle 59 into which is adaptedto be inserted or plugged-the electric power lead 60 of the motor (not shown) used for producing the negative pressure utilized in the present invention. Preferably lead 60 is the electrical power lead 'of an ordinary vacuum cleaner (not shown). In the event a motor is not used for producing negative pressures or in the event a constant speed motor is used whose constant speed develops the proper negative pressures for artificial respiration, or in the event a motor is usedwhose maximum speed will not develop a negative pressure harmful to the patient, voltage regulator 55 can be dispensed with and an adjustable leak valve provided to controlthe pressure delivered to or created within the respirator casing.

Valve apparatus 50 comprises a receptacle 61 attached to platform 53 by means of bolts 111 and having a flanged portion 62 along the top edge thereof to which the edges of a leather bellows .or diaphragm 63 are adaptedto heattachedby bolts 64 and ring 65, the inner walls of receptacle-61 and diaphragm 63 forming an air-tight valve control chamber 61a. Also attached to flange portion 62 by bolts 64 and ring 65 are four bent, upright, chamber supports 66,-the topportions 67 of which are bolted to'the outside wall 68 of cylindrical tive pressure'created by such motonJPrefcfablYhose' 71 is a vacuum tube of an ordinary vacuum .cleaner (not shown) electrical lead 60 of which is connected with voltage regulator 55 by means of receptacle 59. 7

Cylindrical chamber 68a also has an outlet 73 extending therefrom to which is connected, by means of a conventional coupling 74, a delivery conduit or hose 75 which is also connected to the chest respirator v51 in an airtight manner, by means of a conventional coupling 76 whichpasses into the interior of thecasing of the chest respirator. l V Y The casing of the chest respirator is positioned around the chest and sidesof patient 52 so as to form an air.

tight area around the patients'chest and sides. The top portion of the: wall 68 of cylindrical chamber 68a extends inwardly to form a central aperture through the top thereof, which is covered by means of a plate 118 attached to the top of the cylindrical chamber by means of washer 118a and bolts 117a, (see Figs. 4 and 5). Attached to the bottom of plate 118 and'extending downwardly there.- from is a hook 78 (see Fig. 5) to which is attached one end of internal tension spring 79, the other end of which is attached to hook 80 which extends downwardly to the plate 81,which in turn is threaded (not shown) to pin 82,the other end of which has threaded thereto (not shown) plate 83 and hook 84. To one end of. the V hook 84 is attached one end ofan external tension spring 85, the other end, of which is hooked to hook 86, which in turn extends'into bolt head 110, which in turn extends into bolt 87a, which passes through a rigid top diaphragm supporting plate 87, diaphragm 63, and a rigid bottom diaphragm plate..88 and finally flares out. at 89a (see chamber68a by bolts 69 (Fig. 7). Chamber 68:: has a r vacuum inlet extending therefromto which a hole 71 is attached by means of a conventional coupling 72. Hose 71 leads 'to any negative pressure creating means. In the event a motor is used requiring voltage'regulation and such motor is connected to voltage regulator 55, as described above, hose 71 is connected to the source of nega:

Fig. 5). .The bottomportionof the wall 68 of cylindrical chamber68aexte'nds outwardly into flange 88a to which is attached a resilient washer .89 of leather or rubber material, which acts. as a valve seat for. valve plate 90, which is heldrigidly between collar members Hand 92, each of which, together with valve plate 90, has a passage 93 through which pin 82 is adapted to slide vertically upwardly and downwardly. The upper edgeof collar 91 has a flange 94 against which flat portion 81 is adapted to abut through resilient washer 95 and the lower edge of collar 92 has. a flange'96 against which flat portion 83' is adapted to abut through resilient washer 97 (see Fig. 5). I

Adjustably attachedto supports 66 by means of bolts 98 and nuts 99 (see Fig. 5) are valve stop suports '105 having upper inwardly bent flanges 101'to the topof which is attached valve stop plate 102, having attached 7 to its top surface sponge rubber pad 103. A passage 104 is providedthrough pad 103 and plate 102. The upper surface of pad 103'limits the downward movement of plate 90. .The height of the upper surface 'of pad 103 is adjustable by means of a'slot 117 through which 7 bolts 98 pass.

diaphragm 63'is thereforein its upper position, as shown in Figs. 4 and 7,1plate 83 through washer. 97 maintains valve plate tightly against valve seat '89 in -a closed position, as shown in Figs. 4 and '7.

In operation of the apparatus of Figs. 4' to 7, hose 7.1...is, connected to a source ofnegative. pressure. .such

Two of the valve stop supports have flanges 106. which have notches .107 therein' to. receive the hooked ends of springs 108, the other ends of springs .gs,.-th e vas11. m :port 1 of a vacuumcleaner :(notshown) and1hos e-;75 is connected in anair-tight manner to regpi- ;rat or 5;1. In the event ,a motor .is utilized .to provide .r yegative pressure .and such motor is capable of speeds which create ,too great a negative pressure for the ipatientssafety, power'leadfiti of the motor .which creates :the alfigative pressure (when a vacuum cleaner is :used, {the power lead thereof) is plugged into'receptacle-59 of voltage regulator 55 and :power :line 58 is plugged into a source;of;power suchasan ordinary wall socket.

In the :event a motor is utilizedwhich is not capable of creating .excessive negative pressures, the .power line thereofcanbe connected directly tothe: source of power.

After .all the above mentioned connections are com- :.-pleted, switch :56 of regulator 55 .is turned to the on position, .toactuate'the negative pressure creating means (not shown) .Since valve:plate 90is in its normally closed position, asshown in.Figs. :4 and '7, a negative pressure is created in hose 71, chamber 568a, outlet 73, hose '75 and the in- :terior :of respirator 51, whereby inhalation is induced in ;the patient, :and an inhalation period is initiated.

Duringtthis inhalation period, gas escapes from valve control chamber :61a, which is at substantially atmospheric pressure, .through tube 116 and'needle valve 1-14 to chamber 68a, which'is under negative pressure, wherebynegative .pressure is created in chamber '6-1a. The atmospheric pressure exerted on the top of diaphragm 63? causes diaphragm 63 to move downwardly against-the force ofsprings '79 and 85, and pin 82 is caused'to slide downwardly through passage 93 in collars 91 and 92 and valveplate '90, against the force of internal spring 79, until flat portion '81, through resilient washer 95, contacts the ledge 94 of collar 91, after which, further reduction inpressure in chamber 61a, and hence further downward imovement of diaphragm 63, pin =82 and-plate 81 forces collars 91 and 92 and valve plate 99 down- Wardly and valve plate 90 moves away from valve seat 89 to the position shown in 5, whereby chamber 68a, :hose 75-and'the interior-of respirator 51'is open to the atmosphere, the negative pressure therein is neutralized to substantially atmospheric pressure and exhalation is induced in the patient. 7

The top surf-ace of pad 103 which canbe adjusted verticallyby means of bolts '98, nuts'99 andsl'ots117, limits the extentof .the downward movement of valve 90.

At this stage, the pressure in valve control chamber 61a is negative and the pressure in chamber 68a, hose 75 and theinterior of respirator 51 is substantially atmospheric. Therefore gasleaks from chamber 68a t-hrough needle valve "114 and tube 116 into chamberfila. The pressure in chamber 61a 'is thereby gradually increased from negative to atmospheric whereuponthe springs '79 and:85 force diaphragm 63upwardly and spring'79 forces pin 82 upwardly through the passage 93 in collars-91 and 92 and valve plate 90 until flat portion '83 strikes ledge 96 ofcollar 92, through resilient Washer-97, aftenwhich, continued increase of pressure in chamber 61a and'hence further releaseof downward force on pin '82 by diaphragm 63, permits spring "79 to further move pin 82 upwardly whereby collars 91 and92 and valve plate -90 are pushed upwardly until valve plate 90 is sea-ted tightly against Valve seat 89, whereby chamber 68a is closed oif'fr-om the atmosphere, negative. pressure is again built upjtherein as well as in the tube 75 and the interior of chest respirator 51, and an inhalation-period is again initiated. Thereafter, negative pressure is again built-up in chamber 61a and valve plate 90 is again pulled away from valve seat=89, whereby another inhalation period is initiated.

The rate of flow ofgas from chamber 61a to chamber 68aand hence the-rate ofpressure reductionsin chamber 61a and hence the time which elapses before valve 90 opens and hence the time of the inhalation period, is regulated .by-the setting of needle valve 114.

iFEherate offlow of .gas from chamber'68- to receptacle the time :of the exhalation period is dependent upon the setting of needle valve 114 just as the inhalation period is dependent upon the settingof such needle valve.

The. time :of' the exhalation land inhalation PBI'lOdSiS alsodependent zup'on'the length oftpin 82 which determines .theamountof movement of diaphragm :63 before collars 91 and 92 and hence valve 90 are moved .to open and closed position. The greaterthe slideable'lengthof pin 82, the greater'the travel .of diaphragm 63'before it is felt by valve:90, and the longerlit takes before valve'90 is.move'd to open orclosedposition and hence the longer the period of time of the inhalation and exhalation periods.

Furthermore, by lowering support 105 and hence the .topsurface of-valve stop 103 by means of bolts 98,'nu-ts 99 and slots '117 'and .permittingvalve plate to be lowered a .greaterdistance during-exhalation periods, valve 90 has a. greater-distance to travel in order to move to closedposition .to initiate inhalation periods and hence thetime of suchexhalation-periods are increased.

Also, it will :be appreciated that by controlling the design of pin 82, flat portions 81 and 8.3,collars '91 and 92,:valve plate90, :flange 88a-and valve seat 89, the relative time periods of the inhalation vand exhalation can be varied. This is done by arranging these elements so as to control the distance or lost motion of diaphragm 63 before itgac'tuates valve plate '90 to closed and open positions respectively.

It :is also apparent-that the times of both the exhalation and inhalation periods depends not only on the setting of needle valve 1 14, and the length of pin 82, but also upon thertension exerted by springs '79 and on diaphragm 63, the greater the tension of springs 79 and 85, the faster theexhalationperiod, :and t-he-slower the inhalation period. For example, i-f spr'ings79 and 85 assert a relatively great upward forceon diaphragm-63,-a relatively long time must elapse during inhalation periods when the pressure in chamber 68a is negative, before a suflicient negative pressu re'is built up in chamber 61a to overcome such force and open valve plate '90. This results in a relatively long inhalation-period. However, only a relatively short time v elapses during-exhalation periods when the pressure in chamber 68a is substantially atmospheric, before the negative pressure in chamber 61a is sufliciently neutralized topermit springs 79 and 85 to close valve plate This results in a short exhalation period. By reducing the tensioniof springs '79-a-nd "35 the time of the inhalation period is decreased and the time of the exhalation period is correspondingly increased. Therefore, the relative times of the inhalation and exhalation periods can be controlledibyicontrollingthe tension of springs 79 and 85.

Although'the relative times of the inhalation and exhalation iperiods can be controlled -by controlling the tension of springs 7-9 and 85 to assert a greater or lesser upwardforce on diaphragm'63, it is more practical to use springs '108an-d notches 107 since the use thereof provides asimple'adjustable means for regulating the relative timesof the two periods. By utilizing a higher notch, 1 07, .or'a greater number of springs 108, a greater upward force :is applied to diaphragm 63 and hence a. g-rea'tenvacu-um is requiredin chamber 61a to pull the diaphragm .downwardly sufficiently to permit the valve plate '90 to' be-rnoved to open position and hence a longer time is required to-build up this greater vacuum at any particular'needle valve setting, whereby the time of inhalation period is increased in time, as described above. At .the same time less increase in pressure in chamber 61a and hence less time is required during the exhalation period to permit springs 79, 85 and 108 to pull diaphragm 63 upwardly 'su'fiiciently to permit valveplate 90 to close and thereby initiate the inhalation period, [as described above, whereby the time of the exhalation. period --is .de creased.

Thus, by regulating theforce bf springs 108 by means of notches 107, or by varying the number of springs 108, .the ratio of the exhalation time periods and inhalation .time periods can be varied'at will to fit the requirements 7 which will not be harmful to the patient.

However, negative and positive pressure relief valves such as those used in Figs. 2 and 3. can be utilized either instead of or in conjunction with such voltage regulator.

Any suitable pressure responsive or pneumatically movable means may be substituted for the diaphragm disclosed in the drawings and any means for creating a negative pressure other than a motor operated pump, as for example a handoperated bellows, may be utilized in the present invention.

A gauge (not shown) is provided to indicate the pressures within the respirator casing. V

The embodiment of Figs. 8 to 10 This embodiment provides a portable valve apparatus which is capable of providing positive pressure within the respirator casing during exhalation periods and in which the operative connection between the ;valve and valve control means comprises a mechanical linkage. This apparatus may be used not only to cyclically produce alternating positive pressure periods and negative pressure periods, but also to cyclically produce alternating positive pressure periods and atmospheric pressureperiods, or alternately negative pressure periods and atmospheric pressure periods.

With reference to Figs. 8 to 10, the vacuum pump 201 for producing negative pressure, the motor 202'for opcrating said vacuum pump through the shaft 203, and the voltage regulator 204 for regulating the speed of said a motor and hence the negative pressure produced by pump 201 and which is connected to the circuit which energizes the motor, are all mounted on a platform 205 and are surrounded by a substantially air tight housing 206 from which regulating knob 207 of voltage regulator 204 protrudes. Housing 206 has a handle 206a attached thereto for carrying the entire unit. The interior of housing 206 is divided by an air-tight partition 208 intoa negative pres-l sure chamber 209 and a positive pressure chamber 210. Air inlet 211 of pump 201 communicates with negative {pressure chamber209 and air out1et'212 of pump 201 communicates with positive pressure a chamber. 210; Negative pressure chamber 209 is providedwith a negativeipressure port 214 passing through platform 205.

. Positive pressure chamber 210 is;provided with apositive pressure port 215 passing through platform 205. Platform 205 also has a passageway 216 therethrough, one end of which communicates'with one end of the delivery conduit means 217. The other end of conduit '217 com municates with the interior of a respirator casing such as the casing 51 shown in Fig. '4, the casing 1 of Fig. 1,or. the casing of a face mask of a resuscitator'which encloses the patients nose and/or mouth rather than his' body, chest or abdomen, for example,'by connecting'thecon duit 217 to the tube 19'of the face mask Min Figfl fof. UnitedStates Patent No. 2,473,416. The conduitl217. although mounted on the top of platform 205;is located- 12 7 into narrower passageway 221. 'Plate 218 also has assageways 222 and 223 passing therethrough, which lie directly under, are axially aligned with and communicate with ports 214 and-215 respectively. Leg 224 of U- shaped hollow valve conduit 225 is 'rotatably' mounted 'on the bottom of plate 218 directly'below passageway 216 by means of a portion of such leg 224 extending through the passageway 221 in mounting member 219 and thence flaring outwardly .into' a flange which fits into the pocket 220 of member 219, so that the opening at the end of leg 224 covers the bottom of passageway 216 and forms therewith at all times a continuous passageway between U-shaped valve conduit225 and conduit tube 217. Al-' though the flange at the end of leg 224 holds leg 224 to plate 218 so that the opening at the end of leg 224 is at'all times in axial alignment with and communicates with passageway 216, leg 224 is still free to rotate about its axis in passageway 221whicha'cts as a bearing. Pref? erably roller bearings (not shown) are provided in a known manner betweenthe bearing surface of passageway 221 and the, adjacent surface. of leg 224. At the limit of rotation of leg 224 about its axis in' one direction, the

opening in the end of the other leg 2260f U-shaped valve,

conduit 225, is positioned directly under and is axially aligned with passageway 222 and port 214, so as to form conduit 225 is one end of pulley arm 227, the other end tion of the outer surface of cylindrical bearing sleeve 235a, which is rotatably supported on the outer surface.

236 of mounting member 219 soas to be free to rotate about its axis and around mounting member 219, the outer surface of member 219 acting as a bearing surface for the inner surface of sleeve 235a. Sleeve 235a is held in position on member 219 by means of flange219a ex tending outwardly from the bottom of member. 219;

Preferably roller bearings (not .shown) .are provided in V I a known manner between the inner bearing surface of sleeve 235a and the outer bearing surface 236 of member 219. Mid portion 235 extends intoend portions 237 in a directionv tangent to the outer surface 236 of cylin drical member 219. Arcuate member 233 is generally arcuate in shape and its ends are connected to the ends of arcuate member-232.. The mid portion of arcuatemember 232, the outer surface of member 219 and the arcuate member 233 all have a common axis.

Integrally' attached to arcuate member 233 isone end of arm 241, the other end ,of which is pivotally, slidably and adjustably attached to rod 242 by means of collar 243 and. tighteningscrew 244; One end of rod 24 2 is attached to diaphragm 245, the edges of which are atoutside of housing 206; .Attached to'the bottom surface of platform 205 is plate 218 which has a cylindrical mounting member 219 extending fromv the bottom there-. of. Member'219 has a cylindrical pocket 220 which extends downwardly through cylindrical rn errlb er219 tached to flange 246 of receptacle 247 by means of ring 248 and bolts (not shown). Receptacle 247 is attached to platform 204 by means 'ofibracket 248 and bolts (not shown).- Valve control :chamber 250 is formedby the walls. of receptacle'247aand diaphragm 245; Transfer conduit line 251' communicates atone end with conduit 217 and at the other endjwith valve control chamber 250.

A needle valve 252 is located'intrans fer conduit line 251- 7 6 forming a; restricted passage:therein.- Needle valve -252 13 is provided with a handle 253 for adjusting :the size of such restricted passage.

Reciprocal movement of rod 242 to the left and right causes crescent .member234, and bearing sleeve 235:: to rotate about the common axis of arcuate member 233, and mid portion 235 of arcuate member'232 and the .outer surface of cylindrical member 219. Spring 230 anchored at pins 23.1 and stretched :around pulley 228 exerts two forces on pulley 228, pulley arm 227 and leg 226 of U-shaped valve conduit 225 :in 'two different directions, one of which tends to rotate leg 224 about its axis in one direction so as to move leg226 to the position shown in Figs. 8 and 9, wherein negative chamber 209 is communicatively connected with conduit217 and :the interior of the respirator through port 214, passageway 222, U-pipe 225, passageway 221, pocket 220, passageway 216, .and wherein positive pressure chamber 210 communicates with the atmosphere through port 215 and passageway 223. The other .force tends to rotate leg 224 about its axis in the opposite direction so as to move leg 226 to the position shown in Fig. wherein positive pressure chamber 210 is communicatively connected with conduit 217 and the interior of the respirator through port 215, passageway 223, U-shaped valve conduit 225, passageway 221, pocket and passageway 216, and wherein negative pressure chamber 209 communicates with the atmosphere through port 214, and passageway 222.

The actual position of leg 226 depends upon which of these forces is the greatest, which in turn depends upon the angles existing between the portions of springs 230 on either side of pulley 228 and the center line of pulley arm 227, which, in turn depends upon the position of crescent member 234;, which in turn depends upon 'the position of rod 242 and diaphragm 245.

Pulley arm 227, pulley 228, springs 230, crescent member 234 and the outer surface 236 of cylindrical member 219 form a toggle arrangement'wherein upon movement of rod 242 in the direction of .the arrow in.

Fig. '10 in response to movement of diaphragm 2.45, crescent member 234 moves around the surface 23.6 of member 219 without rotation of leg 224 .of U-shaped valve conduit 225 about its axis until a'dead center position is passed, at which time leg 224 is 'rotatedin'the direction shown in Fig. 10 so that leg 226 .moves ,from the position shown in Figs. 8 ,and.9 to the position shown in Fig. 10. Movement of rod 242 in'the reverse direction upon reverse movement of diaphragml245canses crescent 234 to rotate in the direction shown 'in Fig. 9, without rotation of leg .224 about its axis, until a dead center position is passed, whereupon, leg 224 -of :U-shaped valve conduit 225 is instantly rotated about its axis in the direction shown in Fig. '9 andleg226 'is moved from the position shown in Fig. '10 ,to the position :shownrin Fig. 9. Leg 224 is not rotated in response to :rotation of crescent member 234 and hence movement of diaphragm 245 until a dead center position is reached ibecausefthe rotating force in one direction asserted-on'such leg by spring 230 to maintain leg 226 in a position it occupies is not .overcome by the rotating forcein the other direction asserted by springs 230 until a dead center position has been passed.

Spring 260 is attached at one of its ends -to angle member 261 which is attached to platform 204 by means of brace 2'62, and at its other end to rod 242 by means of adjustable collar 264 and tightening screw 265. The force asserted by spring 260 normally'maintains diaphragm 245 and rod 222 in theposition shown in Figs. 8 and 9 so that U-shaped valve conduit 225 is normally maintained in the position shown in Figs. 8 and 9 and negative pressure chamber 209 is communicatively connected to conduit pipe 217 and the interior of the respirator and positive pressure chamber 210 is normally communicatively connected with the atmosphere.

- and a positive pressure is built up therein, wherein ex-' It should be appreciated that. crescent shaped member 234 may be rotatably mounted on member .219 in :any manner so long as a toggle arrangement is obtained. Forexample, crescent shaped member 234 can ;be rota- .tably mounted on one side of .thebottom of member219 so as to have an axis of rotation different from that of U-shaped valve 225 or member 219. In such event member 21 9 has a cylindrical extension extending from .one side of the bottom thereof and the bearing sleeve to which crescent shaped member 234 is attached is rotatably mounted on such extension.

In operation, after :motor 202 has been energized and hence pump 201 has been activated, since valve conduit 225 isin its normal position asshown in Figs. 8 and 9, whereby negative pressure .chamber 209 is communicatively connected with the conduit pipe 217 and the interior or" the respirator through -U-shaped valve conduit 225, air is sucked out of the interior of the respirator, pipe 2-17, U-shaped valve conduit 225 port .2 14 and negative pressure chamber 209 through pump air inlet 211 :and blown from pump air outlet 212 into positive pressure chamber 210 and sent out to the atmosphere through port 215. Thus, a negative pressure is created in negative pressure chamber 209, port 214," Ushaped valve conduit 225, :conduit 217 and the interior of the respirator, whetby' inhalation is induced in the patient and .an inhalation .period is initiated.

During this inhalation period, gas leaks from valve control chamber 250, which is at atmospheric pressure, through-transfer"conduit Eline 25.1;and needle valve .252 to conduitline217, which'is under ,a negative pressure, whereby negative pressure is created in valve control chamber .250. The atmospheric pressure exerted on the outer surface ;of diaphragm 1245 .causes the same and hence rod 242 to move .to the left'against the force lof spring 260, and crescent member 234 to revolve tclockwisezin the direction :slrowniby the z-arrow'in Fig. until it has reached ldeadcenter position. During this movement of diaphragm 245, ;rod 242 .and crescent member 234, the rotational forces applied to leg 224 of 'U-shaped valve conduit 225 by springs 230 are varied. Further reduction ofpressure in-main valve control chamber 250 and hence further movement to the left of diaphragm 245 and rod 242 and hence. further rotation of crescent member 234 and further-shifting vof such rotational forces 'by spring'230, causes leg 224 of U-shaped valve conduit 225 to instantaneously rotate counterclockwise about its axis, thereby causing leg 226 of U-shaped valve conduit 225, pulley arm 228 and pulley 229 to move from the position shown in Figs. 8 and 9 to the position shown in Fig. '10, whereby the interior of the respirator is communicatively connected to the positive pressure chamber 210 through conduit 217, U-shaped valve conduit 225 and port-215 and the negative pressure chamber 209 is-communicatively connected to the atmosphere through port 214. The instantaneous movement of valve conduit 225, pulley arm 228 and pulley 229 forces crescent member 234 from dead center position to the end of its clockwise movement as shown in .Fig. '10.

Air is sucked into negative pressure chamber 209 through port 214 and is blown through port 215, U- shaped valve conduit 225, conduit 217 into the interior of the respirator, whereby the negative pressure in conduit 217 and the interior of the respirator is neutralized halation is induced in the patient and an exhalation period is initiated.

At this stage, the pressure in valve control chamber 250 is negative and the pressure in conduit 217 and the interior of the respirator is positive. Therefore, vgas leaks from conduit 217 through transfer conduit line 251 and needle valve 252 to valve control chamber 250. The pressure in valve control chamber is thereby increased and the atmospheric pressure exerted on the. outside of diaphragm 245 is equalized and finally exceeded, whereby the force exerted by spring 260 and the force exerted by the positive pressure in valve control chamber 250 cause diaphragm 245 and rod 242 to be moved to the right and crescent member 234 to be rotated counterclockwise in the direction shown in Fig. 9. Upon passing a dead center position, the force asserted by spring 230 instantaneously rotates leg 224 of U-shaped valve conduit clockwise about its axis looking at Fig. 9, whereby pulley arm 228, pulley 229 and leg'226 are moved from the position shown in Fig. 10 to the position shovm in Figs. 8 and 9 and the interior of the respirator i-s communicatively connected with negative pressure chamber 209 through conduit 217, U-shaped valve conduit 225 and port 214 and the positive pressure chamber is communicatively connected to the atmosphere through port 215, whereby inhalation is induced in the patient and another inhalation'period is initiated. The instantaneous movement of valve conduit 225, pulley arm 228 and pulley 229snaps crescent member 234 to the end of its counterclockwise movement asshown in Figs. 8 and 9. a

The rate of flow of gas through conduit 251 during the inhalation period and exhalation period, and hence the rate of pressure reductionrand pressure increase in chamber 250 and hence the time which elapses after initiation of an inhalation period before valve 225 is shifted from'the inhalation position shown in Figs. 8 and 9 to the exhalation position shown in Fig. 10, and after initiation of an exhalation period, beforervalve 225 is shifted from the exhalation position shown in .Fig. .10 to the inhalation position shown in Figs. 8 and 9, and hence the time of the inhalation periods and exhalation periods can be regulated by the setting of needle valve 252 to vary the size of the restricted opening thereof.

The times of the exhalation periods and inhalation periods also depend upon the amount of travel or lost motion of rod 242, diaphragm 245 and crescent member 234 before a dead center position is reached and valve conduit 225 is moved from one position to another. It is apparent that varying the particular design and shape of crescent member 234, the travel of crescent member 234, and hence the lost motion of diaphragm 245,v during exhalation and inhalation periods before a dead center position is reached and hence U valve 225 actuated, can be regulated.

The lapse of time, after'initiation of any period, before dead center position is reached and hence the periods are terminated, or, in other words, the lost motion of diaphragm 245 before U shaped .valve 225 is. actuated, can be adjustedby adjusting the :position of collar 243 upon rod 242. By attaching collar 243 to. rod 242 .further to the left and therefore moving crescent member 234 in a clockwise direction closer to its dead center position without corresponding movement of the rod 242, the dead center position will be reached sooner after the initiation of inhalation periods when the pressure is beingreduced in chamber 250 and hence diaphragm 245 and rod 242 are being moved to the left. the time or" the inhalation period is reduced. However, the time of the exhalation period will be increased, since diaphragm 245 and rod 242 must move. a greater .distance to the right from the,,pos'ition shownin Fig. 10 after initiation of the exhalation period and While the pressure is increasedv in chamber 250 before dead center position 'is reached. L By adjusting collar 243 to'the right, the time of,theinhalation'periodis decreased and the time of the exhale. ti-on period is correspondingly increased. Therefore, the

' relative times of the periods can be controlled by the adjustment of collar 243.. on rod 242.

Preferably, the relative times of the periods are ad justed by means of adjusting the tension of spring 269;

which is brought'about .by adjusting the-position of collar! 264 on rod 242. If the tension of spring 260 is increased,

As a result,

16 a'greater negative pressure is required to be built up in valve control chamber 250 during the inhalation period for movement of diaphragm245 and rod 242 sufliciently to the left to actuate U-shaped' conduit valve 225 and hence terminate the inhalation period. Since a longer tirne'must elapse to build up this additional negative pressure, the time of the inhalation period is increased.

However, such increase in the tension of spring 260- decreases the time-of the exhalation period, since after initiation of :such exhalation period the greaterpull exerted on diaphragm 245 and rod 242 by spring 260 moves the same sufficiently far to the right to actuate valve conduit 235 and hence terminate such exhalation period after only a relatively small increase of pressure has been built up in chamber 250. Since such small increase in pressure occurs relatively soon after the initiation of the exhalation period, such period is relatively short. r

By decreasing the tension of spring .260 it is obvious that the inhalation period will be shortened'and the exhalation period will be correspondingly lengthened.

Although spring 260 has been disclosed in the drawing, it is not essential, since diaphragm 245 and rod 242 may be actuated solely by pressure changes within. chamber 250. In such. case the relative time of theperiods can be controlled by'the adjustment'of the position of crescent member234, as described above.

Also, the positive and negative pressure relief, valves of Figs. 2 and3 may be'utilized in the apparatus of'Figs.

-. It should be appreciated that although Figs. 8 to 10 disclose a particular toggle arrangement, any type of known toggle arrangement can be utilized which will provide lost motion of the diaphragm before U-shaped valve 225 is actuated.

The valve apparatus of Figs. 8' to 10 cyclically pro duces alternating positive and negative pressures. How

ever, by providing constantly open communication between the negative pressure chamber 209. and the atmosphere as' by providing a vent of largearea in the wall of the housing 206 surrounding chamber 209, the apparatus cyclically produces alternating positive and atmospheric pressures. In such case, thesp'ring 260 is changed from a tension to a compression spring so as to provide a force which normally maintains the diaphragm 245 and U- shaped valve 225 in the positions shown in Fig. 10. Conversely by providing constantly open communication between the chamber1210' and the atmosphere, as by providing a vent of large area in the wall of housing 206 surroundingchamber 210, the apparatus cyclically duce artificial respiration when" used with 'casings'sure produces alternating negative and atmospheric pressures. Any of these cycles, whether they be negative-positive, atmospheric-negative, or positive-atmospheric, will pro- 7 rounding (a)1theipatients chest and/or abdomen,: as

shown'in Fig. l and Fig. 4, or (b) the patents nose and/ or mouth such as the face mask, shown in U. S: Patent I Io.'2,473,416. In use of a face mask respiration'may be induced by (1) a period of positive pressure (to create inhalation) followed'b'y aperiod of either negative or atmospheric pressure .or, (2) a period of atmospheric pressure (for inhalation) followed by a negative pressure (to create exhalation). 1

Although Figs. 4 to 7 and 8 to l0 (springspribiasing means, as well as 'means for controlling the relative. amount of lost motion 10f the diaphragm), Fig. 3' (con duits 1 65 and 170, two check valves 166 and 171 and' f two diiferently set needle valves 167 and 172) and Figi 2 (atmospheric conduit 13 7, needle valve- 136, conduit means 120, check valve and needlevalve 1 3 6) close particular-means fo'r controllingthe relative times of the periodsof inhalation andexhalation, it will be appreciated that such structures are merelyillustrativ of any means for controlling therelative times" of periods of inhalation and exhalation.

Furthermore, although one particular means for providing lost motion of the diaphragm is disclosed in Figs.- 4 to 7 and another particularmeans, namely, the toggle arrangement, is disclosed in Figs. 8 to 10, the invention includes any means for providing a controlled amount of lost motion of the diaphragm before it actuates the valve means to closed or open position, in order to control the times of the periods of inhalation and exhalation by the same amount or differently with relation to each other.

Although all the drawings'show a diaphragm, any pneumatically movable means can be used.

The valve control chamber, restricted conduit, diaphragm and connections between the diaphragm and valve shown in the drawings are merely illustrative of any pneumatic means, responsive to variations in pressure in the respirator casing or in the delivery conduit means, to actuate or operate the valve means. Furthermore, the restriction in such conduit as shown in the drawings is merely illustrative of any means to control the rate of response of such pneumatic means to pressure variations within the casing, or in the case of a valve control chamber, to control the rate of response of pressure variations in the valve control chamber to pressure variations in the interior of the respirator or in the delivery conduit means.

Although the drawings show applicants novel valve apparatus connected to the interior of a respirator casing enclosing the patients chest and/or abdomen, the present invention includes within its scope the use of such valve apparatus, wherein for example, the delivery conduit means 217 in Figs. 8 to 10, instead of being connected to the interior of such arespirator casing shown in Figs. 1 and 4, is connected with'the interior of a respirator casing which encloses the patients mouth and/ or nose such as the face mask shown in U. S. Patent No. 2,473,416.

The term casing as used herein includes both casings enclosing the chest and abdomen, as shown in Figs. 1 and 4, and masks which enclose the patients mouth and/or nose as shown in U. S. Patent No. 2,473,416, and the term artificial respirator as used herein includes both the tank and/or chest type respirators shown in Figs. 1 and 4 and resuscitators which use face masks but which induce artificial respiration as shown in U. S. Patent 2,473,416.

While the device shown in the drawings provides for the transmission of pressures between the-sources of pressure and the interior of the respirator casing by direct communication between such sources'ofprcssure and the casing interior, it is obvious that any means, such as the pneumatic anaesthesia bag and casing arrangement of my co-pending application Serial No. 279,105, filed March 28, 1952, may be provided for transmission of pressure indirectly between the pressure sources and the interior of the casing.

This application is a continuation in part of application Serial No. 290,856, filed May 31, 1952.

it is to be understood that this disclosure is for the purpose of illustration only and that various changes and equivalents may be made without departing from the spirit and scope of the invention, as defined in the claims.

I claim:

1. Apparatus for producing artificial respiration comprising a substantially air-tight respirator casing to receive and enclose at least part of the users chest but with his head exposed to the atmosphere, a source of negative pressure, a negative pressure conduithaving one end communicating with said negative pressure source and the other end communicating with the interior of the casing, an atmospheric conduit-providing communication between the interior of the casing and the atmosphere, a valve in the atmospheric conduit movable to open and closed position and which, when in open'positiomadmits gas from the atmosphere through the atmospheric conduit to the casing to assist the users exhalation and substantially to neutralize the negative pressure created in the casing by said source of negative pressure during each period of inhalation, electrically operated means to actuate, said valve, a pneumatically operated switch; for controlling said electrically operated means, a transfer conduit providing communication between said pneumatically operated switch and the interior of-the casing, and a check valve in said conduit which is moved to open position by negative pressure in thet-ransfer conduit. and to closed position by at least substantially atmospheric pressure in the conduit whereby said switch is moved in one direction by negative pressure in said transfer circuit by said meansfor continuously creating negative pressure.

2. The combination of claim 1 also comprising means for controlling the effective size of the passage of the ransfer conduit whereby the amount of time required to create sufiicient negative pressure to actuate the switch may be controlled thereby controlling. the duration of the inhalation period of the user.

3. Apparatus for producing artificial respiration comprising a substantially air-tight respirator casingto receive and enclose at least part of the users chest but with his head exposed to the atmosphere, a source of negative pressure, a negative pressure conduit having one end communicating with said source ofnegative pressure and the other end communicating with the interior of the casing, an atmospheric conduit providing communication with the interior of the casing and the atmosphere, a valve in the atmospheric conduit movable to openand. closed position andwhich, when in open position, admits gas from the atmosphere through'the atmosphericconduit to the casing to assist the users exhalation-and-substantially neutralize the negative pressure created in the casing by said source of negative pressure duringeach period of inhalation, electrically operated means to operate said valve, a pneumatically operated switch to control said electrically operating meansra diaphragm in said pneumatically operated switch, a substantially air-tight chamber on one side of said diaphragm, a transfer conduit providing communication between said air-tight chamber and the interior ofthe casing,- a check valve insaid'conduit which is moved to openposition by negative pressure in the transfer conduit and to closed position by at least substantially atmospheric-pressure therein, a'passage providing communication between the interior of said chamber and the atmosphere and means for controlling the efiective size of said passage; whereby negative pressure is created in said chamber when negative pressure is created inthe respirator casing and said switch is moved in one direction when sufiicient-negative pressure is built up in said chamber and said switch is moved in the other direction when the negative pressure in the'chamber has been neutralized by air under atmospheric pressure ad mitted through said atmospheric passage and the amount of time required to neutralize the negative'pressure in said chamber may be controlled by said means'forcontrolling the size of said atmospheric passage.-

4'. Apparatus for producing artificial respiration comprising a substantially air-tight respirator casing to receive and enclose at leastpart of the users chestbutwith his head exposed to the atmosphere, sourceof negative pressure, a negative pressure conduit having one end communicating with one end of said source of negative pressure and the other end communicatingwith the in'- terior of the casing, an atmospheric conduitp'rovidirig communication between the interior of the casingand the atmosphere, avalve in the atmospheric conduit movable to open and closed position and which; when in=open position, admits gas from the atmosphere through the atmospheric conduit through the casing to assist-the users inhalation and substantially to neutralize the negative pressure created in the casing by said source of negative pressure during the period of inhalation,-electrically operated'means to actuate said valve, a pneumatically operated switch controlling'said electrically operated means, a transfer conduitprovidihg communication'betweeh said pneumatically operated switch and the interiorof the casing, a negative pressure by-pass conduit in-said transfer conduit, an atmospheric; by-pass conduit in said transfer conduit, a negative pressure check valve in said negasaid pressures are alternately delivered to the interior of said casing;means for controlling the operation of said valve means through a cycle comprising two alternating periods, during one of which periods said' valve means is actuated to provide for the transmission of pressure of said one magnitude between said first source of pressure and the interior of said casing, and during the other of which periods said valve means is actuated to provide 7 i for the transmission of pressure of said different magnipheric by-pass conduit and to closed position by negative pressure therein, whereby said switch is moved in one direction by negative pressure created in said negative pressure by-pass conduit and in the other direction by at least substantially atmospheric pressure created in said atmospheric by-pass conduit.

The combination of claim 4 also comprising means for controlling the effective size of the passage of the negative pressureby-pass and means for controlling the efifective size of the passage of the atmospheric pressure by-pass, whereby the amount'of timenecessary to create sufiicient negative pressure to actuate the switch in one direction and duration of the period of inhalation may be controlled by the first control means, and the amount of the time necessary to counteract negative pressure created at the switch sufl'iciently to actuate the switch in the other direction and the duration of the period of exhalation may be controlled by the second control means.

6. The combination of claim 5 also comprising means for controlling the efiective size of the transfer conduit, whereby the duration of the combined periods of exhalation and-inhalation may be controlled. v

7. Apparatus for producing artificial respiration comprising a substantially air-tight respirator casing to receive and enclose at least part of the users chest but with his head exposed to the atmosphere,'a negative pressure conduit communicating with the casing, suction means contude between said second source of pressure and the in-.

terior of said casing whereby said pressure of one magnitude is maintained in the interior of sa1d casing durmg a portion of said one period and pressure of said dlfierent magnitude is maintained in the interior of said casnected with the negative pressure conduit for creating negative pressure within the casing to assist the users inhalation, an atmospheric conduit providing communication between the interior of the casing and the atmosphere, a valve in the atmospheric conduit movable to open and closed position and which, when in open position, admits at least substantially atmospheric or positive pressure to the casingto assist the users exhalation, a pressure responsive'control means including a diaphragm and a diaphragm operating switch, electrical means for opening and closing the valve and a circuit electrically interconnecting the switch with 'said electrical means, the switch when closed being operative to close the circuit to energize said electrical means and to open the valve and the switch when open being operative to open the circuit to de-energize the electrical means and to close the valve, a transferconduit interconnecting the atmospheric conduit with the diaphragm. for exposing the diaphragm to variations of the pressure in the atmospheric conduit and adjustable valves in the transfer conduit for regulating the flow of air existing in said transfer conduit 'at said'variations of pressure through said transfer conduit 'at a rate so as to expose the diaphragm thereto at intervals, said diaphragm being responsive to said variations of pressure to close and open the switch at said intervals.

8. Apparatus for producing artificial respiration, comprising a substantially air-tight respirator casing, a first source of pressure of one magnitude, a second source of pressure of a different magnitude, a conduit system providing for the transmission of said pressures between said first and second sources of pressure and the interior of said casing, valve means in said conduit system adapted to be operated to alternately provide for the transmission of pressure of said one magnitude between said first source and the interior of said casing and of pressure of said difierent magnitude between said second source of pressure and the interior of said casing whereby ing during a portion of the other of said periods, said means for controlling the operation of said valve' means comprising a valve control chamber, means for actuating said valve means in response to pressure variations in said valve control chamber and pneumatic means for varying the pressure in said valve control chamber in response to variations in pressure in the interior of said casing, said latter means including means for controlling the rate of response of pressure variations in said valve control chamber to pressure variations in the interior of said casing, said means for controlling the operation of said valve means including means-for controlling the time of each period independently of the other said last mentioned means being remote from said valve means and including at least as a part thereof said means'for controlling the rate of response of pressure variations in said valverchamber to pressure variations in the interior of said chamber. 7 i

9. Apparatus for producing artificial respiration comprising a substantially air-tight respirator casing to receive and enclose at least a part of the users chest but adapted to give the user access to the atmosphere for breathing purposes, a source of negative pressure, a sec ond source of pressure which is substantially greater'in magnitude than said negative pressure, a conduit system for providing for the transmission of said'pressures' between said negative pressure source, said second pressure source and the interior of said casing, valve means in said conduit system adapted to be operated to alternately provide for the transmission of said negative pressure between said negative pressure source and the interior of said casing and to provide for transmission of said second pressure of greater magnitude between said second pressure source and the interior of said casing so as to create within the interior of said casing alternate pressures, one ofwhich is said negative pressure and other of which is said pressure of substantially greater magnitude than said negative pressure, means for controlling the operation of said valve means through a cycle com-- negative pressure source and the interior of said casing to produce'and-maintain said negative pressure within said casing during a portion of said one. period whereby inhalation is induced in the user, and during the other of said periods said valve means is actuated to provide for the transmission of said pressure of greater magnitude between said second source of pressure and the interior of said casing to produce and maintain within said casing during a portion of said other period said pressure of greater magnitudethan said negative pressure whereby exhalation is induced in the user, said valve control means comprising a valve control chamber, means responsive to pressure variations in said chamber for operating said valve means through said cycle, and means for cyclically varying the pressure in said chamber to cyclically actuate said valve operating means through said cycle, said'chamber pressure varying means including transfer conduit means providing for the flow of gases into and out of said chamber, said transfer conduit means having. means for restricting the operable size thereof and hence the rate of fiow'ofgas-thereth'rough, said means for controlling the operation of said valve meansincluding means for controlling the time of each period independently ofthe other, said last mentioned means beingremotefrom said valve means and including at least as a part thereofsaid transfer conduit means.

Apparatus for producing artificial respiration, comprising'delivery conduit means adapted to'be operably connected with'a respirator casing, a first source of pressure of one magnitude, a second source of pressure of a different magnitude, a'conduit'system providing for the transmission of said pressures betwe'e'n'said first and second sources of pressure and said delivery conduit means, valve means in said conduit system' adapted to be operated to alternately'p'rovide for the transmission of pressure of said one magnitude between said first source of'pressure and said delivery conduit means and of pressure of said different magnitude between said second source of pressure and said' delivery conduit means whereby said pressures are alternately delivered to said delivery conduit means, means for controlling'the operation of said valve means through a cycle comprising two alternating periods, during one of which periods said valve means is actuated to provide for the transmission of pressure of said one magnitude between said first source and said delivery conduit means, and during the other of which periods said valve means is actuated to provide for the transmission of pressure of said diiferent magnitude between said second source of pressure and the interior of said casing, whereby said pressure of one magnitude is delivered to said delivery conduit means during a portion of said one period and said pressure of said different magnitude is delivered to saiddelivery con duit means during a portion of the other of said periods, saidmeans for controlling the operation of said valve means comprising a valve control chamber, means for actuating-said valve means in response to pressure varia'tions'in said valve control chamber, said chamber pressure varying means including transfer conduit means providing for the flow of gases into and out of said chamber, said transfer conduit means having means for restricting the operable size thereof, said means for controlling the operation of saidvalve means alsocompris ing means for controllingthe time of eachperiod independently of the other, said last mentioned means being remote from said valve means and including at least as a part thereof said transfer conduit means.

11. The apparatus of claim 10 having means for adjusting the operable size of said transfer conduit means to control the flow of gas therethrough.

12. The apparatus of claim 10, wherein said valve operating means includes means movable to a first position in response to pressures in said valve-control chamber below a first particular pressure and to a second position in response to pressures in said valve chamber above a second particular pressure, said movable means when in said first position and moving therefrom to said second position operating said valve means through said one time period or" said cycle and when in said second position and moving therefrom toward said first position operating said valve means through said other time period of the cycle, the length of time of said periods depending upon the length of time for said movable means to be moved fromsaid first position to said second position and from said second position to said first position respectively and hence upon the rate of movement of said movable means from said first position to said secondposition and from said second position to said first position'respectively, which in turn depends upon the rate of pressure variation in said valve chamber between said first particular pressure and said second'particular pressure and between said second particular pressureand said first particular-pressure respectively, which in turn depends upon the rate of'fiow of gas out of said chamber through said transfer conduit means and restricting means during said one p eriod an d upon therate 'of fiow o'f'g'a's i'nto saidchamber through said transfen conduit means during said other period, which" in turn depends uponthe operable size'of said transfer conduit means.-

13. The apparatus of claim 12' wherein the operable connection between said movable means and'said valve means; is provided with adjustable meansfor permitting an adjustable amount of lost motion ofsaid movable means between said first and second'positionswithout actuation of said valve me'ans'to'thereby adjust the times of the periods of said cycle;

14. Theappar'atus' of claim 10 whereinsaid' pressure of one magnitude is a negative pressure and'saidpres'sure of a ditferent magnitude is substantially the pressure of the atmosphere outside the casing.

15. The apparatus of claim 10 wherein one of said pressures of different magnitudes is a positive pressure and the other is a negative pressure.

16. Apparatus for producing artificial respiration, com prising delivery conduit'me'ans adapted to be operably connected with the interior of a respirator casing, means for transmitting and maintaining a pressure of one magnitude to said delivery conduit means, means for delivering and maintaining a pressure of a different magnitude to said delivery conduit means, valve means associated withsaid pressure transmittingmeans and adapted to be operated to alternately provide for the'transmission and maintenance of said pressure of one magnitude and said pressure of a different magnitude to and in said delivery conduit means, means for controlling the'operation of said valve means through a cycle comprising two'alterna-ting periods, during one of which periods said valve means is actuated to provide for the transmission and maintenance of said pressureof one magnitude to said delivery conduit means, and during the other of which periods said valve means is actuated toprovide for the transmission and maintenance of said pressure of adiflierent magnitude to said delivery conduit means, said means for controlling the operation of said valve means comprising a valve control chamber, means responsive to pressure variations in said chamber for operating said valve means through said cycle, and means for varying thepressure'in said valve chamber in response to variations in pressure in said delivery conduit'means, said pressure varying means including transfer conduit means for providing communication between said delivery conduit means and said chamber, said transfer conduit means having means for restricting the operable size thereof and hence the rate of flow of gas therethrough to a rate which is'substantially less than the rate of gas flow through said valve means, said-meansfor controlling theoperation of said valve means also comprising'means' for cdntrolling the-time of each period independently of tlfeother, said last mentioned means being remote from'said valve means and including at least as apart thereof said'transferconduit means;

17. Apparatus for producing'artificial respiration, comprising delivery conduit means, means for transmittin'g'a pressure of one magnitude to said delivery conduitmeans', means for delivering a pressure of a ditferent magnitude to said delivery conduit means, valve'means associated with saidpressure transmitting means and adapted to'be operated to alternately provide for the transmission o'f said pressure of one magnitude and-said pressureof a different magnitude to said delivery conduit means, means for controlling the operation of said'valve means through a cycle comprising two alternating periods, during one-of which periods said valve means is actuated to provide for the transmission of said pressure of one' magnitude to said delivery conduit means, and during theiother' of which periods said valve means is actuated to provide for the transmission of said pressure ofa different magnitude to said delivery conduit means, said means for controlling the operation of said valve means comprising a valve control chamber, means responsive to pressure variationsV-in said chamber for operating said valve means through saidtcycle, and means for varying'the pressure in said valve chamber in response to variationstin pressure in said'delivery conduit means, said means for controlling. the operation of said valve means including transfer conduit means for providing for flow of gas into and out of said chamber, said transfer conduit means having means for restricting the operable size thereof to restrict the flow of gas therethrough to a rate which is less than the rate of flow through said valve means, said means for controlling the operation of said valve means also including means for controlling the times of said periods with respect to each other, said last mentioned means being remote from said valve means. i

T 18. Apparatus for producing artificial respiration, comprising deliveryconduit means adapted to be operably connected to the interior of a respirator casing, means for. transmitting a pressure of one magnitude to said de livery conduit means, means for transmitting a pressure of a different magnitude to said delivery conduit means, valve means associated with said pressure transmitting means and adapted to be operated to alternately provide for the transmission of said pressure of one magnitude and said pressure of a different magnitude to said delivery conduit means, means for controlling the operation of said valve means through a 'cycle comprising two alternating periods, during one of which periods said valve means is actuated to provide for the transmission of said. pressure of one magnitude to said delivery conduit means,'and during the other of which periods said valve means is actuated to provide for the transmission of said pressure of a different magnitude to said delivery conduit means, said means for controlling the operation of said valve means comprising a valve control chamber, means responsive to pressure variations in said chamber for operating said valve mzans through said cycle and means for varying the pressure in said chamber in response to variations in pressure in the delivery conduit means, said pressure varying means including means for providing for the flow of gas into said chamber and meansvfor providing for the flow of gas out of said chamber,'said means for providing outward flow having means for restricting the operable size thereof to restrict the flow of gas therethrough to a rate which is less than the rate of flow through said valve means and a check valve permitting how of 'gas therethrough in only one direction, said means for providing inward flow having means for restricting the operable size thereof to restrict the flow I of gas therethrough to atrate which is less than the rate of flow through said valve means and a check valve.

, 19. The apparatus of claim 18 wherein at least one of said means for providing inward flow and said means for providing outward flow provide communication between said chamber and the atmosphere. 7

20. Apparatus for producing artificial respiration coniprising a substantially air-tight respirator casing, means for transmitting a pressure of one. magnitude to the interior of said casing, means for transmitting a pressure of a different magnitude to the interior of said casing, valve means associated with said pressure transmitting means and adapted to be operated to alternately provide for the transmission of said pressure of one magnitude and said pressure of a different magnitude to the interior 7 ,snonsive topressure variations in said chamber for operating said valve means through said cycle, and means for varying the-pressure in said chamberin response to variations in pressure in the interior of said casing, said pressure varying means including transfer conduit means for providing communication between said chamber and. the interior of said casing, said transfer conduit means having means for restricting the. operable size thereof and the rate of flow of gas therethrough to a rate which is substantially less than the rate of gas flow through said valve means, said transfer conduit means having a check valve permitting the flow of gas therethrough in only one direction, said 'means for controlling the operation of said valve means also comprising atmospheric transfer conduit means for communicating directlybetween ,the valve chamber and the atmosphere, said atmospheric transfer conduit means having means for restricting the operable size thereof, the length of time of one of said periods being determined by the operable size of said transfer conduit means and the length of time of the other of said periodstbeing determined by the operable size of said atmospheric transfer conduit means.

21. Apparatus for producing artificial respiration comprising delivery conduit means adapted to, provide operable communication with the interior of a respirator casing, means for transmitting a pressure of one magnitude to said delivery conduit means, means for transmittinga pressure of a different magnitude to' said, delivery conduit means, valve means associated with said pressure transmitting means and adapted to be operated to alternately provide for the transmission of said pressure of one magnitude and said pressure of a different magnitude to and in said delivery conduit means, means for controlling the operation of said valve means through a cycle comprising two alternating periods, during one of which periods said valve means is actuated to provide for the transmission of said pressure of one magnitude to said delivery conduit means, and during the otherof which periods said valve means is actuated to provide for the transmission of said pressure of a different magnitude to and in said delivery conduit means, said means fortcontrolling the operation of said valve means comprising a valve control chamber, means responsive to pressure variations in said chamber for operating said valve means through said cycle, and means for cyclically varying the pressure in said chamber to cyclically actuate said valve operating means through said cycle, said chamber pres sure varying means including transfer conduit means for a providing direct communication between said chamber and the'atmosphere, said transfer conduit means having means for restricting the operable size thereof andthence the rate of flow of gas therethrough to a rate which is less than the rate of flow through said valve means and also having a check valve.

' 22. Apparatus for producing artificial respirationcomprising a delivery conduit, a negative pressure conduit providing operative communication between a source of negative pressure and said delivery conduit, 'an atmospheric port providing communication between the atmosphere and the negative pressure conduit, 21 valve in said atmospheric port for alternately opening and closing said negative pressure conduit to the atmosphere, acontrol chamber, means, responsive to pressure variations in said chamber, for automatically actuating said valve through a predetermined time cycle, means, responsive to pressure Y variations in said delivery conduit, for automatically varya ing the pressure in said chamber to automatically actuate said valve through said cycle, said last mentioned means including means for adjusting the rate of response of pressurevariations in said chamber to pressure changes in said delivery conduit from negative pressure'to atmospheric pressure by the opening of said valve and from atmospheric pressure to negative pressureby the closing of said valve, said last mentioned means'cornprising a control conduit providing for the flow of'gas alternately into saidchamberto increasethe pressure therein and out of said chamber to decrease the pressure therein, said conduit having restriction means to restrict the rate of flow therethrough to a rate which is less than the rate of flow through said valve, and means for adjusting the relative durations of the periods of said cycle, said last mentioned means being remote from said valve.

23. Apparatus for producing artificial respiration, comprising delivery conduit means, means for transmitting a pressure of one magnitude to said delivery conduit means, means for delivering a pressure of a difierent magnitude to said delivery conduit means, valve means associated with said pressure transmitting means and adapted to be operated to alternately provide for the transmission of said pressure of one magnitude and said pressure of a different magnitude to said delivery conduit means, means for controlling the operation of said valve means through a cycle comprising two alternating periods, during one of which, said valve means is actuated to provide for the transmission of said pressure of one magnitude to said delivery conduit means, and during the other of which periods, said valve means is actuated to provide for the transmission of said pressure of a different magnitude to said delivery conduit means, said means for controlling the operation of said valve means comprising a valve control chamber, means responsive to pressure variations in said chamber for operating said valve means through said cycle, and means for varying the pressure in said valve chamber in response to variations in pressure insaid delivery conduit means, said means for controlling the operation of said valve means including transfer conduit means for providing for flow of gas into and out of said chamber, said transfer conduit means having means for restricting the operable size thereof to restrict the flow of gas therethrough to a rate which is less than the rate of flow through said valve means, said means for controlling the operation of said valve means also including means for controlling the time of each period independently of the other, said last mentioned means being remote from said valve means and including at least as a part thereof said transfer conduit means.

24. The apparatus of claim 23 wherein said transfer conduit means comprises first transfer conduit means for flow of gas into said chamber and second transfer conduit means for flow of gas out of said chamber, each of said first and second transfer conduit means having meansfor restricting the operable size thereof to restrict the flow of gas therethrough to a rate which is less than the rate of flow through said valve means and a check valve.

References Cited in the file of this patent UNITED STATES PATENTS Re. 23,845 Seeler June 29, 1954 1,917,940 Heidbrink July 11, 1933 2,055,128 Herrmann Sept. 22, 1936 2,088,044 Tate July 27, 1937 2,223,570 McMillin Dec. 3, 1940 2,273,790 Raymond Feb. 17, 1942 2,436,853 Coleman Mar. 2, 1948 2,456,724 Mullikin Dec. 21, 1948

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