US3662751A

US3662751A - Automatic respirator-inhalation therapy device

Info

Publication number: US3662751A
Application number: US38948A
Authority: US
Inventors: Clare E Barkalow; Ilden R Folkerth
Original assignee: Michigan Instruments Inc
Current assignee: Michigan Instruments Inc
Priority date: 1970-05-20
Filing date: 1970-05-20
Publication date: 1972-05-16
Anticipated expiration: 1989-05-16

Abstract

A primary control valve when open permits the flow of a pressurized oxygen containing gas from a source to a patient adapter for use by the patient. A pressure control means controls the opening of the primary valve and is responsive to a subambient pressure in the adapter caused by initial patient inhalation to actuate the primary valve to an open position. A pair of adjustable timing mechanisms control the lapse time for the primary valve in the open or closed position. The timing mechanism controlling the time during which the primary valve is closed is subservient to the pressure control means so that patient inhalation causes the valve to open prior to the preselected lapse time. It may also be turned off to permit gas flow only as a result of patient inhalation. A pressure regulator is also provided to prevent flow pressures in the adapter above a predetermined level. A mechanism is also provided to adjust the level of output flow to meet varying patient needs.

Description

United States Patent Barkalow et al.

[54] AUTOMATIC RESPIRATOR- INHALATION THERAPY DEVICE [72] Inventors: Clare E. Barkalow, Comstock Park; Ilden R. Folkerth, Sparta, both of Mich. v [73] Assignee: Michigan Instruments, Inc., Grand Rapids,

Mich.

[22] Filed: May 20, 1970 [21] Appl. No.: 38,948

[52] U.S.Cl ..128/145.8 [51] Int. Cl. ..A62b 7/04 [58] Field ofSearch ..128/145.8, 145.5, 145.6, 145.7, 128/142-1423 [56] References Cited UNITED STATES PATENTS 3,221,734 12/1965 Beasley ..l28/l45.8 3,068,856 12/1962 Bird et al. .....l28 /145.5 3,523,527 8/1970 Foster .128/145.8 X 3,191,596 6/1965 Bird et a1. ..l28/l45.5

Primary Examiner-Richard A. Gaudet Assistant Examiner-J. B. Mitchell Attorney-Price, l-leneveld, l-luizenga & Cooper [57] ABSTRACT A primary control valve when open permits the flow of a pressurized oxygen containing gas from a source to a patient adapter for use by the patient. A pressure control means controls the opening of the primary valve and is responsive to a sub-ambient pressure in the adapter caused by initial patient inhalation to actuate the primary valve to an open position. A

pair of adjustable timing mechanisms control the lapse time 18 Claims, 3 Drawing Figures May 16, 1972- AUTOMATIC RESPIRATORJNHALATION THERAPY DEVICE BACKGROUND OF INVENTION This invention relates to therapeutic inhalation devices and, more specifically, to an automatically intermittent positive pressure ventilator providing pressure limited, full-volume ventilation.

Various respirators or intermittentpressure ventilators have been proposed, the more common consisting of a magnetic toggle valve which opens upon inhalation by a patient and which closes when a predetermined pressure is present in the face mask or adapter. During ventilation, back pressure is created essentially by ventilatory resistance and compliance. Back pressure due to resistance to air passage to the lungs tends to be a maximum at the initiation of ventilation while that due to compliance becomes a maximum at the. end of ventilation when the lungs are full.

A critical problem in the prior art has been the immediate cessation of flow when the predetermined pressure level is reached, This can occur many times at the initiation of ventilation when the patient attempts to inhale causing the backpressure due to resistance to reach the predetermined pressure level, shutting the flow off. This is particularly likely if the patients airway resistance is high, and the inhalation device setting of flow rate is excessive. This, is extremely undesirable since the patient has not achieved proper ventilation. Thus, if the patient desires to use these devices, he mustleam to con trol air flow during inhalation so that the back pressure does not reach the shut-off level until adequate ventilation is achieved. This problem is also critical when used on apneic patients since constant care and adjustment by the technician is required. In these cases, premature shut-off causing inadequate ventilation may be corrected by reducing output flow an unnatural and confusing adjustment.

One alternative has been suggested which incorporates a bellows into the system which will provide variable volume delivery at a constant pressure level. These and other alternatives to date have proven to be very complexvand costly and they require constant adjustment by a skilled technician and hence are not easily adapted to home use. In addition, none of the prior art suggests a simple way of timing the ventilation cycle while providing variable flow at a preselected pressure level. Such an accomplishment would provide maximum supportive therapy to any patient having pulmonary deficiencies requiring attention and in the automatic mode, would provide respiration for the apneic patient. i

SUMMARY or INVENTION It is a principle object of this invention to provide an inter mittent positive pressure ventilator means capable of providing variable full-volume ventilation at a preselected pressure level over an adjustable predeterminedlength of time.

It is a further principle object of this invention to provide an apparatus having the capabilities aforementioned which is at all times responsive in operation to initial patient inhalation to trigger the ventilation cycle and in addition provide a means for automatically triggering the ventilation cycle in the event the patient becomes apneic, or in pulmonary arrest.

It is yet another object of this invention to provide an automatic intermittent positive pressure ventilator which includes adjustment means capable of operation by an unskilled patient which will vary both the on and off time cycle of the ventilator as well as the pressure level of the oxygen containingsupply gas.

For achievement of these and other objects apparent to those skilled in the art, this invention provides a primary pres sure supply conduit means adapted to receive a pressurized oxygen containing gas from a source and deliver the gas to a patient adapter for ventilatory use by the patient. A primary control valve in the supply conduit permits flow to the adapter when open and prevents flow when closed. The primary valve may be actuated to open by two separate and adjustable control means. The first control means is responsive to a subaambient pressure in the adapter caused by the instance of patient inhalation and the second control means automatically opens the primary valve after a predetermined time lapse, this latter mentioned means being at all times subservient to voluntary instigation by the patient. A third adjustment control means causes the primary valve to close after a predetermined time has elapsed. Means are also provided for selecting and maintaining a maximum pressure level in the patient adapter so that excessive ventilation cannot occur. Other means are provided for selecting a range of output flow rates for best matching of the patients needs.

The advantages of the apparatus briefly described above are significant. Individual patients have multifarious needs and requirements based on such factors as individual ventilatory compliance and resistance, flow rate requirements, volume requirements, pressure requirements, and other variables too numerous to mention as forexample physician technique. In addition, the supportive therapy requirements for one patient do change as the patient improves his breathing habits and capabilities, and responds to therapy. The apparatus provided by this invention permits easy adjustment by either a skilled technician or the patient himself in order to adjust to changing needs. In addition, the automatic cycling means provided by the invention permits maintenance of ventilation for the apneic patient in a device which is extremely attractive from both economical and reliability viewpoints.

DESCRIPTION OF THE DRAWINGS FIG. I is a pneumatic circuit diagram of the intermittent positive pressure ventilator provided by this invention;

FIG. 2 is a cross-sectional view of the pressure valve provided by this invention; and

FIG. 3 is a cross-sectional view of the primary control valve provided by this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, reference is particularly made to FIG. 1 showing the pneumatic circuit which makes up they invention. The major components of this circuit are the input line 10 (far left), leading to a patient adapter 34 (far right) through-the

lines

18, 22, 26, and .28 and venturi gain 7 mechanism 30. The flow of the gas or air through these lines is indirectly controlled by the bi-stable pressure sensitive control valve 60. Regulator means 24 is provided in the lines to the adapter 34 for regulating the pressure therein; An important aspect of this invention is the timing mechanism designated by reference numeral 92, which controls the time during which the primary control valve is open and closed so as to time-control the feeding of compressed air or oxygen to the adapter.

Referring more specifically to the details of FIG. 1, input line 10 which is in communication with an oxygen containing gas source or other source of air (not shown), 1 leads to a manual on-off switch valve 12 which must be in the on position as shown for the system to operate. The, gas passes through valve 12 directly into a filter. 14 provided to improve overall. system reliability. A pressure gauge 16 is preferably provided downstream of the switch outlet providing a visual readout of the source pressure.

The gas flow-leaving filter 14 in line 10 is diverted into two

separate linesv

18 and 62. The primary line 18 feeds directly into the primary control valve 20, and when valve;20 is open, the gas flow feeds directly through valve 20 into a primary line 22 connected directly into regulator means .24. Regulator means 24 permits flow of the gas source through

primary lines

26 and 28 directly into a venturi gain mechanism 30, through a throttle valve orifice 32 directly into the patient adapter 34 for use by the patient as a ventilation aid. Adapter 34 is shown to include a conventional mouthpiece 36 well-known in the art and it will be appreciated that in lieu of a mouthpiece, a face mask or other desirable means could be used. The primary flow of the oxygen or compressed air is thus established.

Turning briefly to the venturi gain mechanism 30 and throttle valve orifice 32, the venturi gain mechanism 30 is described in detail in copending application entitled Inhalation Positive Pressure Breathing Apparatus filed Oct. 7, 1968, Ser. No. 765,468, issued as US. Pat. No. 3,610,237, which application is incorporated herein by reference.

Herein, however, provision is made to switch in several different venturi configurations whereby the output flow characteristic can be more closely matched to the patients needs. These different combinations of venturi geometrical configurations are shown to be carried in a slide 37 which would be positioned by the physician or technician to best match the patients needs. Another, more scientific, concept is the matching of the internal venturi resistance to the resistance of the patient to achieve more efficient and uniform performance.

The venturi gain mechanism 30 also provides a mixing mechanism. Thus, if primary oxygen is used, the ambient air drawn into the venturi opening 38 mixes with the primary oxygen, and the diluted mixture is delivered to the patient, representing a first step in oxygen enrichment over pure air. If further enrichment is desired, a bleed conduit 40 off the primary line source 26 can provide a flow of into the interior of the venturi for additional enrichment. An adjustable bleed valve 42 is provided to regulate the degree of enrichment.

In addition, throttle valve orifice 32 which is regulated by a throttle valve 44 provides a controlled rate of acceleration of the flow to the patient during the inspirational phase. That is, it has been found that a gradual increase in the flow rate and inspirational pressure during inspiration decreases turbulance so that a more uniform difusion of breathing gas into the pulmonary alveoli is promoted. A more efficient pulmonary gas exchange is then realized. It is therefore desirable to gradually increase the pressure and flow rate of air entering the lungs. Throttling valve 44 provides this controlled rate of acceleration of flow to the patient during the inspirational phase. Also, when the primary control valve is closed, the throttle valve 44 isolates the primary flow lines from the patient adapter 34 in order that a slight inhalation by the patient will create a subambient pressure in the adapter, the purpose of which will be discussed hereinafter. The details of throttle valve 44 and throttle valve orifice 32 omitted in that they are likewise described in detail in the above-identified copending application.

In addition to the primary line flow, an auxiliary line 46 is in communication with the primary line 22 downstream of the primary control valve. Line 46 communicates directly from primary line 22 into pressure regulator 50 and thence to the patient adapter through a nebulizer 48 permitting the patient to receive medication mixed in with the oxygen containing gas Along with nebulizer 48, a non-rebreathing valve 49 is provided to permit exhalation by the user to atmosphere without retrograde flow of exhaled air back through the breathing hose. The operation of the nebulizer and nonrebreathing valve are also described in the above-identified application.

As mentioned previously, primary line 22 upon leaving the primary control valve feeds into a regulator means 24 which permits regulated flow through

primary line

26, 28 into the patient adapter. The regulator means includes a valve positioned on the primary line between the primary control valve and the patient adapter in order to regulate and maintain a preselected flow pressure in the adapter and likewise prevent that pressure from exceeding a preselected maximum. An adapter pressure feedback line 52 is connected to adapter 34 for feeding back the exact pressure in the patient adapter to the regulator means 24 and the pressure sensitive control valve 60. Line 52 feeds branches into line 54 which communicates directly with regulator valve 24 and line 70 which communicates directly with pressure sensitive control valve 60. Valve 24 is also in direct communication with the primary line downstream of the primary control valve 20 via line 56. An additional regulator 58 is provided to control the pressure on regulator valve 24 off the primary line.

Resistors

23, 25 and 27 provide smooth flow during the on and off cycling of the regulator and in addition, resistor 25 takes care of any spool leakage to maintain regulator accuracy.

Preferably, regulator valve 24 is a diaphragm valve responsive to both the pressure derived from main flow of oxygen containing gas through the system and the pressure of the oxygen containing gas in the patient adapter. This is accomplished by means of bleeding off from the primary line 22 a line 56 which has its own pressure regulator 58, and also feeding back the pressure from adapter 34 through the feedback lines 52 and 54. The valve 24 is responsive in a well-known conventional way to the differential between these pressures in order to regulate the pressure of the gas or air flowing into line 26. The details of this regulator valve 24 are omitted in this specification in that they are fully described in US. Pat. No. 3,461,860 issued Aug. 19, 1969 and assigned to the assignee of record herein.

The pressure sensitive control valve 60, as previously stated, is provided in the system for actuating the primary control valve 20 from a closed to open position. Pressure sensitive control valve 60 is in direct communication with the primary line 10 which is upstream of the primary control valve 20 as well as in communication with the control valve itself. This is accomplished by an input line 62 which brings the gas directly from its source through a regulator 64 into the pressure sensitive control valve 60. The regulator 64 is provided in line 62 since it is undesirable to have full source pressure operating through the pressure valve. In addition, a more precise control of pressure is desired. Line 66 is provided between the pressure sensitive control valve 60 and primary control valve 20 so that when the pressure sensitive control valve is in an open position, the flow through line 62a passes through the pressure sensitive control valve into line 66 which flow, as will be described hereinafter, acts on the primary control valve to open it. A one-way check valve 68 is provided in line 66 to permit one-way flow to the primary control valve. Pressure sensitive control valve 60 is also in direct communication with the patient adapter 34 through feedback line 70 which is connected directly to line 52. The details of pressure sensitive control valve 60 will be described in more detail hereinafter but the essential operation is that when a sub-ambient pressure is registered in adapter 34, it is fed back through

lines

52, 70 to pressure sensitive control valve 60, in which sub-ambient pressure acts upon a diaphragm in the pressure valve causing the valve to open. Upon opening, gas flow is permitted from the source through

lines

62, 66 and 67 into the primary control valve causing it to open. Once the primary control valve is opened, the flow through

lines

66 and 67 passes directly through the primary control valve into a return line 72 which feeds into a venturi pump 74 attached to the pressure sensitive control valve 60. The function of venturi pump 74 is to immediately reset pressure control sensitive valve 60 into a closed position rendering it ready for use on the next cycle, i.e. after complete ventilation has occurred and the primary control valve is once more closed. Venturi pump 74 also provides an exhaust to atmosphere for line 72 to prevent any pressure remaining in line 72 which might oppose the operation of pressure sensitive control valve 60. An exhaust bore 76 is also provided in pressure sensitive control valve 60 for bleeding any pressure in line 66 which might remain after the primary control valve is closed.

Turning now to a more detailed description of the pressure sensitive control valve 60, FIG. 2 shows in detail the preferred construction of the control valve which produces the function just described.

Pressure sensitive control valve 60 is a bi-stable valve in the sense that it is actuated into a completely open or closed position. Valve 60 is generally T-shaped in cross section with the horizontal portion defining a pressure chamber 102 while the vertical portion 104 includes an annular tube section 106 for receipt of a spool-type valve 108. Spool 108 is positioned within the annular tube 106 and adapted to reciprocate with respect thereto. A reduced diameter portion 110 is provided to establish communication between

lines

62 and 66 via

ports

112 and 114 when spool 108 is in the uppermost (open) position with respect to tube 106. A plate 1 16 is fixed to the top of spool 108 and secures a flexible diaphragm 118 which divides pressure chamber 102 into upper and lower portions. The vertical portion 104 of valve 60 also includes an enlarged annular tube 120 extending from annular tube 106. Tube 120 defines a pressure chamber 122 in the vicinity of the lower portion of spool 108. A dipole magnet 124 is adjustably mounted to the bottom portion of tube 120 within pressure chamber 122 and aligned with a second dipole magnet 126 permanently affixed to the bottom end portion of spool valve 108. Dipole magnet 124 is mounted for adjustment in the rotational sense about the axis of

annular tubes

106 and 120. When the poles of the

adjacent magnets

124 and 126 are lined up, a maximum attractive force is provided between them. When however, magnet 124 is rotated with respect to magnet 126, the attractive force between the magnets decreases. This provides a simple means for adjusting the magnetic impact of the dipole magnets. A port 128 is provided into chamber 122 and connects line 66a to line 66 so that when the pressure sensitive control valve 60 is open, flow communicated between

lines

62 and 66 will also be directed into pressure chamber 122. The purpose for this and the operation of valve 60 will now be explained.

To begin with, pressure sensitive control valve 60 is shown in FIG. 2 in a neutral position which it is incapable of achieving since it is a bi-stable valve. This is done for the sake of clarity of description. Assuming for the moment that the valve is in a closed position, spool 108 would be in its lowermost position with

magnets

124, 126 in coercive proximity with each other. In this position, the upper non-reduced portion 130 of spool 108 would block flow from line 62 through port 112. The exhaust port 128 is open providing a bleed for

lines

66, 66a which bleeds off any trapped air upstream of check valve 68. The travel of spool 108 is such that a portion of the reduced diameter portion 110 of the spool will always be exposed to line 66 so that line 66 is either communicating directly with line 62 when the pressure valve is open or it is communicating with the exhaust port 128 when the valve is closed.

As stated previously, the function of pressure sensitive control valve 60 is to actuate the primary control valve 20 when patient inhalation begins. When the user begins to inhale on adapter. 34, a sub-ambient pressure is created on the order of one centimeter of H 0 referring to a water manometer. A negative pressure on the order of one centimeter of water is sufficient to actuate the pressure sensitive control valve. This negative pressure is communicated through

lines

52, 70 and port 132 into pressure chamber 102 on the upper side of diaphragm 118. This negative pressure acting on the entire area of diaphragm 118 is sufficient to overcome the coercive force of the dipole magnets. Once spool displacement occurs, and there is communication between

pressure lines

62, 66, the flow through line 66 also flows through line 66a into pressure chamber 122 contributing towards complete displacement of spool 108 into the open position by virtue of the pressure applied over the area of the spool end. With spool 108 in its uppermost position, exhaust port 128 is closed, and there is direct communication between

line

62, 66 to actuate the primary control valve 20.

Before turning to the details of the primary control valve 20, a description of the reset venturi 74 would be helpful. Once the primary control valve 20 is open, the flow through

line

66, 67 feeds into line 72 directly into reset venturi 74. The function of the reset venturi is two-fold. One, it provides an exhaust to atmosphere forthe flow just described and two, it closes the pressure control valve in preparation for the next breathing cycle. Venturi 74 has a straight through feed line 136 providing the exhaust to atmosphere for flow through line 72 and a port 138 normal to line 72, 136 which port feeds into the lower portion of pressure chamber 102 providing a subambient pressure when there is flow through line 72. The subambient pressure created by reset venturi 74 acting on diaphragm 118 is sufficient to overcome the force which maintains valve 60 in the open position. This force is essentially created by the flow through line 66a into pressure chamber 122. Once spool 108 begins its downward or closing movement the coercive force of

dipole magnets

124 and 126 along with the sub-ambient pressure created by reset venturi 74 completely closes pressure sensitive control valve 60. As this pressure sensitive control valve 60 is closed, flow ceases through

lines

66, 72, and the force of the dipole magnets is sufficient to insure full closure of the valve. Since there is flow through line 28 into the adapter 34, positive pressure will be registered through feed back

lines

52, 70 so that the pressure control valve 60 will not open until ventilation has ceased and the next inhalation cycle begins.

For convenience, a pressure gauge 78 provides a visual readout of the pressure in line 52 which indicates the pressure in the patient adapter 34 and

line

54 and 70. Gauge 78 preferably registers both positive and negative ambient pressures so that one can immediately ascertain whether a sub-ambient pressure is being registered for purposes of activating pressure sensitive control valve 60 through line 70 while on the other hand gauge 78 also permits a visual registration of the positive pressure during flow which pressure is important for purposes of control of the regulator valve 24 and the selection of proper venturi characteristic by adjustment of slide 37.

The regulated source pressure feeding in through line 62a into the pressure sensitive control valve 60 is also routed through two timing

mechanisms

84 and 92. Line 82 feeds the timer mechanism 84 and line feeds timer mechanism 92.

Mechanism 84 automatically turns the primary valve 20 on after a preselected time has elapsed in the event that the primary valve is not triggered by pressure sensitive control valve 60. The automatic triggering of primary valve 20 is especially important in situations where the patient is apneic or there is a possibility of pulmonary arrest. It assures the ventilation at selected time periods if the patient is incapable of initiating it himself.

Mechanism 84 includes a manual on-off switch valve 86 which permits elimination of control means 84 from the system if it is desired. Many users requiring ventilation assistance are in no danger of a pulmonary arrest and would prefer not having a timed off" control in the system.

Various timing mechanisms could be employed, however, it is preferred that in a pneumatic system as described, the combination of a needle valve 88 and accumulator 90 be used. Needle valve 88 permits varying the flow volume through line 82 into the accumulator. The accumulator, somewhat analagous to an electrical capacitor is a fixed volume chamber which retards the buildup of internal pressure needed to activate the primary control valve, as will be described hereinafter. It will be appreciated that the regulated air passing from the source into line 62a has more than sufficient pressure to open the primary control valve 20 when the pressure sensitive control valve 60 opens. This same regulated air passes from line 62, 62b into line 82 and the accumulator 90 is capable of reaching substantially the same pressure as the regulated pressure in line 62a. This is more than sufficient to open the primary control valve 20, and thus controlled How in 824 through needle valve 88 determined the time of opening of valve 20. Check valve 68 prevents flow from the accumulator back up to the control valve 60 through line 66 during this process.

The regulated air passing through line 62b also controls the timing mechanism 92 comprising line 80, needle valve 94, lines 96a, 96b and 96c which communicate through valve 20 and accumulator 98. Line 960 feeds into the top of the primary control valve 20 to provide a control as will be explained in detail hereinafter. Timing mechanism 92 is constantly effective in the system and performs the very important function of timing the ventilation cycle; i.e., the time during which the primary control valve 20 is open. The operation of timing mechanism 92 is somewhat similar to that described previously with respect to timing mechanism 84. That is, an adjustable needle valve 94 controls the rate of flow through line 80. When the primary control valve 20 is closed, flow is prevented through control valve 20. However, when control valve 20 is open, flow is permitted from line 96a directly through control valve 20 to line 96b feeding into accumulator 98. When accumulator 98 is sufficiently filled, its pressure is communicated through line 960, to close valve 20 thus stopping further ventilation. Any air entrapped in lines 96b, 96c and accumulator 98 are exhausted through port 182 in valve 20, the details of which will be described shortly. The time duration during which primary control valve 20 is open is easily adjustable by simply adjusting needle valve 94 to control the volume flow into accumulator 98 when the primary control valve is open. It is significant to control the elapsed time during which the primary control valve 20 is open supplying ventilation to the patient. It prevents premature cessation of the flow to the patient, and, in addition, assists the patient in developing good breathing habits. Should the patient reach complete ventilation prior to the primary control valve being closed, the ventilatory back pressure and compliance will be substantially equal to the primary source pressure and hence flow will cease. Thus, no patient discomfort is felt.

The details of the primary control valve 20 will now be described and reference is made in particular to FIG. 3. Valve 20 is formed from an annular body 140 having enlarged ends 142, 144. The enlarged ends are hollow and define cylindrical chambers 146, 148. An elongated spool 150 is positioned within the hollow central portion of the annular body 140 and adapted to slide longitudinally with respect thereto. Valve 20 is a bi-stable valve similar to pressure valve 60 in that it is adapted to function in either a completely closed or open position. In order to achieve this, a pair of magnets 152 and 154 are positioned in each enlarged end of the valve. A cylindrical armature 156 is affixed to the upper end of spool 150 with a somewhat similar armature 158 affixed to the lower end. The spool 150 is shown for the sake of clarity in FIG. 3 as being in a neutral position. In reality, the spool except when actuated will always be in either an uppermost (open) position wherein armature 156 is in coercive proximity with magnet 152 or armature 158 is in coercive proximity with magnet 154 in the downwardmost (closed) position. Armature 156 is slightly different than armature 158 in that it functions also as a piston which moves up and down as the spool moves. Thus, chamber 146 is a pressure chamber with an O ring 160 sealing pressure chamber 146 into an upper and lower portion.

Spool 150 has a plurality of reduced diameter portions 162, I64, 166, defining a plurality of communicating

chambers

168, 170 and 172. Inlet and outlet ports are provided through the annular body 140 with respect to each

communication chamber

168, 170 and 172. The inlet and outlet ports are as follows: with respect to chamber 168, inlet port 174 is connected to line 67a while outlet port 176 is connected to line 72; with respect to chamber 170, inlet port 178 is connected to line 96a while outlet port 180 is connected to 96b. In addition, an exhaust port 182 communicates with chamber 170 and leads to atmosphere, the significance of which will be explained hereinafter. With respect to chamber 172, an inlet port 184 leads to line 18 while the outlet port 186 leads to line 22. When valve 20 is closed, spool 150 is in the downwardmost position with armature 158 in coercive proximity with magnet 154. In this position, spool portion 188 prevents line 18 from communicating with line 22; spool portion 190 prevents line 96a from communicating with line 96b although communication between line 96b and exhaust port 182 is established; and spool portion 192 prevents communication between lines 670 and 72. When valve 20 is open, spool 150 is in the upwardmost position with armature-piston 156 in coercive proximity with magnet 152. In this position, communication is established between the lines referred to previously except that spool portion 188 now prevents exhaust port 182 from communicating with chamber 170, permitting only communication between lines 96a and 96b through chamber 170.

Having established the various communicating lines feeding into and out of the central portion of valve 20, it is desirable at this time to describe in detail how valve 20 is opened and closed. When valve 20 is closed, the volume of the lower portion of pressure chamber 146 is a minimum. The port 194 communicates with the lower portion of pressure chamber 146 and leads to a line 67b which connects with line 67. To open valve 20, it is necessary to establish sufficient pressure in the lower portion of pressure chamber 146 to act on piston 156 and overcome the coercive force between magnet 154 and armature 158 to move piston 156 and spool 150 upwards into coercive proximity with magnet 152 and armature 156. This is accomplished by feeding pressurized flow through line 67 into branch 67b through port 194 into the lower portion of pressure chamber 146. Flow through line 67 is provided from two sources: timing mechanism 84 and/or pressure valve 60 when activated to permit flow through line 66. Both of these sources have been described in detail before and hence will not be repeated. Once valve 20 is opened, flow is established through

primary lines

18, 22 through chamber portion 172.

In order to close valve 20, it is necessary to provide sufficient pressure in the upper portion of pressure chamber 146 to act on piston 156 and overcome the coercive force of magnet 152 to move the piston and spool down until armature 158 is in coercive proximity with magnet 154. A port 196 leads into the upper portion of chamber 146 and is connected to line 96c which communicates the pressurized flow to the upper portion of chamber 146. Flow into the upper portion of chamber 146 is provided by timing mechanism 92 described herein before. Briefly, this flow passes from the regulated air through line 62 to line 80, through needle valve 94 and line 96a. When primary control valve 20 is open, the flow in line 96a passes through chamber 170 in the control valve into line 96b dumping into accumulator 98. When sufficient pressure has built up in accumulator 98, the pressurized air in line 960 will pass into the upper portion of chamber 146 actuating the piston 156 and spool 150 into a closed position. Once valve 20 is closed, communication between lines 96a and 96b is prevented. In order to bleed off any excess or entrapped pressurized air in lines 96b, 96c, accumulator 98 and upper portion of chamber 146 so that the timing cycle is precise, an exhaust port 182 is provided in valve 20 for communication with line 96b when the spool valve is closed. Port 182 simply dumps this entrapped air to atmosphere.

Finally, means are provided for manually operating valve 20 when desirable. A handle 200 is mounted through end 144 and affixed to armature 158. Simple exertion upwards or downwards will manually open or close the valve.

OPERATION Referring now to FIG. 1, input line 10 in operation is connected to a source of pressurized oxygen containing gas and, when valve 12 is in the open position as shown, filtered air through filter 14 is provided for use. Flow through the primary line 18 is prevented until the primary control valve 20 is opened. The alternative flow route of filtered air through line 10 is through line 62 which is regulated by regulator 64. Flow of regulated air through line 62 is prevented through line 62a by the pressure valve 60 when it is closed. Flow through line 62b leads into lines and 82 with the former being blocked by the primary control valve 20 when it is closed and the latter being fed into the automatic timing mechanism 88 which operates only when the switch 86 is in the on" position as shown.

Assuming for the moment that the user or patient is apneic or that there is a good chance of pulmonary arrest, it will be desirable that the automatic actuation of valve 20 be achieved. With switch 86 in the on position as shown in FIG. 1, regulated air passes through needle valve 88 which is adjustable by the physician or technician into accumulator 90. When the pressure build-up in accumulator is sufficient, communicating through line 82b into line 67, 67b, into the lower portion of chamber 146 in control valve 20, it opens the valve. Once this happens, flow through the primary line 18 is communicated through control valve 20 to line 22 on through the regulator 24 into

line

26, 28, through the venturi 30 and throttling orifice 32 into the patient adapter 34 for use by the patient. At the same time, regulated air flow is permitted through line 80 through timing mechanism 92 which times the ventilation cycle. Air in line 80 passes through needle valve 94 (again adjustable by the physician or technician) into line 960, through control valve 20 into line 96b into accumulator 98 into line 96c and upper portion of chamber 146. When the pressure build-up in the upper portion of chamber 146 reaches the preselected level, valve 20 is actuated into a closed position. Immediately thereafter, timing mechanism 84 begins to take effect again with pressure building up in accumulator 90 to time the period valve is to remain closed.

If at any time the patient begins the ventilatory cycle himself by inhaling, the control valve 60 comes into play. This will happen regardless of whether or not switch 86 is in the on or off" position. When the primary control valve 20 is closed, the spring biased throttle valve 44 is extended into throttle orifice 32 blocking flow past the orifice. In this position, when the patient begins to inhale, a static sub-ambient pressure is created in the adapter line 34 up to the throttle orifice 32. This sub-ambient pressure is communicated through feed back

lines

52, 70, to control valve 60. When a subambient pressure is recorded, it acts on diaphragm 118 to open the pressure sensitive control valve. Upon opening, flow is permitted from regulated air line 62 through line 62a into line 66, which in turn feeds through line 67 and 67b actuating the primary control valve 20 into an open position. Once this occurs, timing mechanism 92 begins functioning to time the ventilation cycle. When valve 20 is open, flow through line 67, 67a is directed through line 72 into reset venturi 74 to reset the control valve 60 into a closed position.

Once valve 20 is open and flow is established through

primary lines

18, 22, the pressure regulator valve 24 controls flow through

lines

26, 28 into adapter 34 to prevent excessive pressure levels from being attained and yet permitting the proper volume flow in order to meet the patients needs. It is important to note that should the patient or user be properly ventilated prior to timing mechanism 94 turning the system off, no damage or discomfort is felt by the user. When the patient has finished his breathing cycle, the ventilatory back pressure and compliance pressure reaches the maximum permissable pressure selected by the pressure regulator 24. When this occurs, flow through

primary lines

18, 22, 26 and 28 simply reduce, although the pressure level remains until timing mechanism 84 closes valve 20. Herein lies the advantage of being able to manually adjust the

timing mechanisms

84 and 92. If after several ventilation cycles, it is apparent that either phase is too long or too short, the physician or technician, or user himself may simply adjust needle valves 88 or 94, respectively.

It will be obvious to those having ordinary skill in this art that the details of construction of this particular preferred embodiment may be modified in a great many ways without de-v parting from the unique concepts presented. It is therefore intended that the invention is limited only by the scope of the appended claims rather than by particular details of construction shown, except as specifically stated in the claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An automatic respirator-inhalation therapy device comprising, in combination: a patient adapter;

a primary pressure supply conduit means adapted to receive pressurized gas from a source and deliver said gas to said patient adapter for use;

a primary control valve means in said supply conduit means and operative when open to permit flow of said gas to said adapter, and operative when closed to prevent said gas flow;

first control means operatively associated with said control valve means and adapter, said control means being responsive to the pressure in said adapter so that when there is a predetermined sub-ambient pressure condition in the adapter, such sub-ambient pressure is communicated to said control means causing it to open said control valve means; and

second control means operatively associated with said primary control valve means to maintain said primary control valve means open a predetermined time and to close said control valve means after a predetermined time has elapsed, said second control means including adjustment means for adjusting said predetermined elapsed time.

2. The combination according to claim 1 wherein said combination further includes a pressure regulator means responsive to the flow pressure in said adapter so as to prevent said flow pressure from attaining a pressure higher than a predetermined level, said regulator means including adjustment means for selecting a predetermined pressure level.

3. The combination of claim 2 in which a means is provided for varying the flow rate to said adapter to substantially match the flow intake impedances of different patients.

4. The combination of claim 3 in which said primary control valve is actuated into closed and opened position in response to pneumatic pressure from said primary pressure supply conduit means.

5. The combination according to claim 4 in which the first control means is a pressure responsive valve means actuated in response to the pressure in said adapter and connected between said primary pressure supply conduit means and said primary control valve means.

6. The combination of claim 4 in which said second control means is a manually adjustable restrictor valve means connected to said supply conduit means, the degree of restriction controlling the said predetermined time required to build up sufficient pressure to actuate said primary control valve closed.

7. The combination of claim 1 in which a means is provided for varying the flow rate to said adapter to substantially match the flow intake impedances of different patients.

8. The combination of claim 1 in which said primary control valve is actuated into closed and opened position in response to pneumatic pressure from said primary pressure supply conduit means.

9. The combination according to claim 8 in which the first control means is a pressure responsive valve means actuated in response to the pressure in said adapter and connected between said primary pressure supply conduit means and said primary control valve means.

10. The combination of claim 8 in which said second control means is a manually adjustable restrictor valve means connected to said supply conduit means, the degree of restriction controlling the said predetermined time required to build up sufficient pressure to actuate said primary control valve closed.

11. An automatic respirator-inhalation therapy device comprising, in combination:

a primary pressure supply conduit means adapted to receive pressurized gas from a source and deliver said gas to a patient adapter for use;

a primary control valve means in said supply conduit means and operative when open to permit flow of said gas to said adapter, and operative when closed to prevent said gas flow, said primary control valve means being actuated into closed and opened positions in response to pneumatic pressure from said primary pressure supply conduit means;

first control means operatively associated with said control valve means and adapter, said first control means comprising a bi-stable pressure responsive valve means actuated in response to the pressure in said adapter and connected between said primary pressure supply conduit means and said primary control valve means, said bi-stable valve means being actuated into a closed position by a vacuum created by a venturi means operatively connected to said primary pressure conduit means through said pressure responsive valve means and said primary control valve means, said first control means being responsive to the pressure in said adapter so that when there is a predetermined sub-ambient pressure condition in the adapter, such sub-ambient pressure is communicated to said control means causing it to open said primary control valve means;

and second control means operatively associated with said primary control valve means to close said control valve means after a predetermined time has elapsed, said second control means including adjustment means for adjusting said predetermined elapsed time.

12. The combination of claim 11 in which a third control means is operatively associated with said primary control valve means to open said primary control means after a predetermined time has elapsed.

13. The combination of claim 12 in which said third control means is a manually adjustable restrictor valve means connected to said supply conduit means, the degree of restriction controlling the said predetermined time required to build up sufficient pressure to actuate said primary control valve open.

14. The combination of claim 13 in which said second control means is a manually adjustable restrictor valve means connected to said supply conduit means, the degree of restriction controlling the said predetermined time required to build up sufiicient pressure to actuate said primary control valve closed.

15. The combination of claim 11 wherein said combination further includes a pressure regulator means responsive to the flow pressure in said adapter so as to prevent said flow pressure from obtaining a pressure higher than a predetermined level, said regulator means including adjustment means for selecting a predetermined pressure level, and means are provided for varying the flow rate to said adapter to substantially match the flow intake impedances of different patients.

16. The combination of claim 15 in which a third control means is operatively associated with said primary control valve means to open said primary control means after a predeten'nined time has elapsed.

17. The combination of claim 16 in which said third control means is a manually adjustable restrictor valve means connected to said supply conduit means, the degree of restriction controlling the said predetermined time required to build up sufficient pressure to actuate said primary control valve open.

18. The combination of claim 17 in which said second control means is a manually adjustable restrictor valve means connected to said supply conduit means, the degree of restriction controlling the said predetermined time required to build up sufficient pressure to actuate said primary control valve closed.

Claims

1. An automatic respirator-inhalation therapy device comprising, in combination: a patient adapter; a primary pressure supply conduit means adapted to receive pressurized gas from a source and deliver said gas to said patient adapter for use; a primary control vaLve means in said supply conduit means and operative when open to permit flow of said gas to said adapter, and operative when closed to prevent said gas flow; first control means operatively associated with said control valve means and adapter, said control means being responsive to the pressure in said adapter so that when there is a predetermined sub-ambient pressure condition in the adapter, such sub-ambient pressure is communicated to said control means causing it to open said control valve means; and second control means operatively associated with said primary control valve means to maintain said primary control valve means open a predetermined time and to close said control valve means after a predetermined time has elapsed, said second control means including adjustment means for adjusting said predetermined elapsed time.

11. An automatic respirator-inhalation therapy device comprising, in combination: a primary pressure supply conduit means adapted to receive pressurized gas from a source and deliver said gas to a patient adapter for use; a primary control valve means in said supply conduit means and operative when open to permit flow of said gas to said adapter, and operative when closed to prevent said gas flow, said primary control valve means being actuated into closed and opened positions in response to pneumatic pressure from said primary pressure supply conduit means; first control means operatively associated with said control valve means and adapter, said first control means comprising a bi-stable pressure responsive valve means actuated in response to the pressure in said adapter and connected between said primary pressure supply conduit means and said primary control valve means, said bi-stable valve means being actuaTed into a closed position by a vacuum created by a venturi means operatively connected to said primary pressure conduit means through said pressure responsive valve means and said primary control valve means, said first control means being responsive to the pressure in said adapter so that when there is a predetermined sub-ambient pressure condition in the adapter, such sub-ambient pressure is communicated to said control means causing it to open said primary control valve means; and second control means operatively associated with said primary control valve means to close said control valve means after a predetermined time has elapsed, said second control means including adjustment means for adjusting said predetermined elapsed time.

14. The combination of claim 13 in which said second control means is a manually adjustable restrictor valve means connected to said supply conduit means, the degree of restriction controlling the said predetermined time required to build up sufficient pressure to actuate said primary control valve closed.

16. The combination of claim 15 in which a third control means is operatively associated with said primary control valve means to open said primary control means after a predetermined time has elapsed.