US3754550A - Cyclically operated medical respirators - Google Patents

Cyclically operated medical respirators Download PDF

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Publication number
US3754550A
US3754550A US00072349A US3754550DA US3754550A US 3754550 A US3754550 A US 3754550A US 00072349 A US00072349 A US 00072349A US 3754550D A US3754550D A US 3754550DA US 3754550 A US3754550 A US 3754550A
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pneumatic
pressure
change
mode
valve
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B Kipling
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Honeywell BV
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Pye Ltd
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. ventilators; Tracheal tubes
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. ventilators; Tracheal tubes
    • A61M16/0003—Accessories therefor, e.g. sensors, vibrators, negative pressure
    • A61M16/0009—Accessories therefor, e.g. sensors, vibrators, negative pressure with sub-atmospheric pressure, e.g. during expiration
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. ventilators; Tracheal tubes
    • A61M16/0057—Pumps therefor
    • A61M16/0075—Bellows-type
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/8593—Systems
    • Y10T137/86389—Programmer or timer
    • Y10T137/86397—With independent valve controller

Definitions

  • a pneumatic drive circuit which operates the respirator inspiratory and expiratory control valves in accordance with any one or more of the three modes of cycling, viz. time cycling, volume cycling or pressure cycling. Separate mode selection is provided for terminating the inspiratory and expiratory periods, each period being terminated at an instant determined by the selected parameter or the first one of the selected parameters.
  • pneumatic control apparatus for a multi mode respirator having an inspiration control valve comprises a gas flow path for operating said inspiration control valve, a change-over valve device for adjusting the gas flow in said gas flow path at the end of each of the inspiration and expiration periods and at least two switch devices for controlling the flow of gas to operate the changeover valve device, which switch devices are each responsive to a different one of the parameters time, pressure of gas flowing to the patient or volume of gas flowing to-the patient and switch device selector means operable to select switch devices to be effective to control the gas flow to the change-over switch so that the inspiration control valve is controlled in accordance with any selected one or more of the said parameters.
  • multimode control of the termination of the inspiration period is obtained by selection of the appropriate switch devices so-that this period is terminated in accordance with one selected parameter or in accordance with the first condition to occurof two or more selected parameters.
  • the expiration period may be terminated'in the known manner by a time control.
  • a pneumatic control apparatus forv amultiple mode respirator having an inspiration control valve and an expiration control valve which comprises gas flow paths for operating said inspiration and said expiration control valves, a-change-over device for adjusting the gas flow in said gas-flow paths at the end of each of the inspiration and expiration. periods and at least two.
  • switch devices for controlling flow of gas to operatethe change-over valve device at the end of an inspiration period and at the end of an expiration period, which switch devices are each responsive to a different one of the parameters time, pressure or volume of gas flowing to or from the patient and switch device selector means operable to select to one or other of two control inlets and operable to i switch devices to be effective to control gas flow to the change-over switch so that at least one said control valve is controlled in dependence on any selected one or on more than one of the said parameters.
  • the selector means enable one or more switch devices to be made effective to terminate an inspiration or expiration period.
  • the period is terminated when the first of the selected switches operates.
  • Each of the switches controls the flow of gas to operate the change-over valve and thus the subsequent operation in that cycle of a second switch is of no effect.
  • the control apparatus is pneumatic thereby avoiding the hazards which can arise with the use of electricity in the administration of certain anaesthetic gases.
  • each set preferably includes three switch devices responsive respectively, for the switch devices operating at the end of the inspiration period, to time, pressure of gas flowing to the patient and volume of gas flowing to the patient and, for the switch devices operating at the end of the expiration period, to time, pressure of gas flowing from the patient and volume of gas flowing from the patient.
  • the switch devices of each set may control three gas passages connected in parallel between a control inlet to said change-over valve and a source of gas pressure controlled by said valve.
  • the changeover valve device comprises a valve change-over mem ber movable in dependence on the gas pressure applied connect a main inlet from a source of gas pressure to either of one or other of two outlets, each of said out lets being connected either directly to said gas flow cir cuit or indirectly to control gas supply to said. gas flow circuit and also to one of the control inlets through one set of said parallel connected switch controlled pas; sages whereby two sets of switch devices, control' re-' spectively the flow of gas to said control inlets.
  • any switch device of the appropriate set to terminate an inspiration or expiration period will cause gas to flow through one of the parallel connected passages to the control inlet to cause the change-over valve member. to move.
  • the valve change-over member may comprise a shuttle member connected between twopiston devices slidable within a cylinder, the shuttle member being ar-' ranged to move across the said main inlet between the two outlets to connect the main inlet to one or other of' the two outlets, and two venting 'outlets are provided in the cylinder and controlled by movement of the two piston devices respectively.
  • each control inlet is connected through a non-return valve to a controlled vent to atmosphere.”
  • the aforementioned change-over valve may, from two outputs, control respectively inspiration and expiration valves of the respirator. Preferably however this is done indirectly, these two outputs controlling a further change-over valve which provides two alternative outputs which control respectively inspiration and expiration valves. This enables a consant air pressure to be rapidly established in the pipes between the two control valves (which pipes can be relatively short) irrespective of any use made of the output from the second change-over valve.
  • the or each switch device may comprise an adjustable pneumatic delay including a piston operated through a restricted orifice.
  • this switch device is fed from the appropriate output of the first change-over valve so that the full pressure is applied quickly to the time delay after operation of the changeover valve.
  • the paths through the switch devices however are preferably fed from the appropriate output of the second change-over valve. This prevents any leakage in the switch devices and assorted parts of the apparatus from having any effect on the time delay.
  • the invention includes a multiple mode respirator having pneumatic control apparatus as described above.
  • FIG. 1 shows diagrammatically a pneumatic control apparatus for a medical respirator
  • FIG. 2 shows a medical respirator to which the pneumatic control apparatus of FIG. 1 is connected.
  • the pneumatic control apparatus is entirely pneumatic with no electrical parts. It is designed to be used in medical respirators having a valve or valves controlling gas flow to or from a patient, e.g. such as that described in the specification of the aforementioned British Pat. No. l l62l5l, the pneumatic drive replacing the electrical drive circuit described in that specification, for operating the inspiration and expiration control valves of the respirator.
  • a constant pressure e.g. 60 psi
  • a source 8 such as a compressed air cylinder with a pressure regulator
  • a manually operated valve 10 acting as an ON/OFF switch
  • the valve is shown in the OFF position.
  • air pressure is applied through a pipe 12, previously vented to atmosphere, to a main inlet port 18 of a five port change-over valve 13, such as Type KV9/025 as manufactured by Kay pneumatics of London Road, Dunstable, Bedfordshire, England.
  • This change-over valve 13 in its first position (shown), directs the air pressure to a first air pipe 14 which is connected to a control port 15 of a second change-over valve 16, to maintain that valve in the position shown.
  • a pipe 17 connects pipe 12 to a main inlet port 19 of the second change-over valve 16, so that, in the position shown, an air pipe 20 receives pressurised air.
  • air pipe 14 is vented to atmosphere through a port 21 and a second air pipe 22, previously vented through a port 23, receives pressurised air, so applying pressure to another control port 24 of valve 16.
  • valve 16 As air pipe 14 is vented, the pressure at port 24 operates valve 16 to its second position in which air pipe 20 is vented through a port 25 of valve 16 and in which an air pipe 26, previously vented through a port 9 of valve 16, receives pressure.
  • the inclusion of valve 16 assists in the rapid establishment of a constant air pressure in air pipes 14 and 22 irrespective of the manner in which pressure in air pipes 20 and 26 is used.
  • valve 13 Pressure applied to a first control port 27 of valve 13 causes valve 13 to take up its first position (as shown) and pressure applied to a second control port 28 operates the valve l3 to its second position, provided that the circuit connected to the control port 27 or 28 not receiving pressure allows the discharge of entrained air.
  • the change-over valves 13 and 16 employed do not require air pressure to be continuously applied to a control port to maintain a particular position; the valve remains in a position determined by a pulse of pressure applied to one control port until again operated by a pulse of pressure applied to the other control port.
  • Pressure is applied to control ports 27 and 28 by first and second control pipes 29 and 30 respectively. Pressure for these control pipes is obtained as follows. Pressure from air pipe 26 is passed through a pipe 31 to three inspiratory mode selection switches 32, 33 and 34 shown in their OFF position and, from the selection switches, may be passed via respective mode switches 35, 36 and -37 also shown in their non-operated OFF position, to control pipe 29. Pressure from air pipe 20 is similarly passed along a pipe 38 to expiratory mode selection switches 39, 40 and 41 and thence via respective mode switches 42, 43 and 44 to control pipe 30, these expiratory mode selection switches and mode switches also being shown in their OFF or nonoperated position.
  • the inspiratory pressure mode switch 35 is operated to establish an air passage by outward movement of a diaphragm 45 of a positive pressure sensor 46 connected to the patient gas circuit of the medical respirator by a line 47.
  • the expiratory pressure mode switch 42 is operated similarly by inward movement of a diaphragm 48 of a negative pressure sensor 49 connected to the patient gas circuit of the medical respirator by a line 50.
  • the inspiratory volume mode switch 36 is opened to establish an air passage by downward movement of one end 51 of a lever 52, pivoted at its other end, under the control of the volume of gas passing to the patient.
  • the expiratory volume mode switch 43 establishes an air passage on upward movement of one end 53 of a similarly pivoted lever 54 controlled by the volume of gas passing from a patient.
  • switches 37 and 44 which are of differential pressure type, are time dependent. These two switches are similar with the exception that they receive operating pressure from different points in the circuit.
  • Switch 37 has its high pressure side supplied from pipe 31 and its low pressure side from a pipe I54 connected to air pipe 22 whereas the high pressure side supply for switch.44 is taken from pipe 38 and the low pressure side is supplied through a pipe 55 from air pipe 14.
  • the high pressure sides of switches 37 and 44 are fed from a constant source of pressure such as pipes 11, 12 or 17.
  • each switch 37 and 44 contain means 75 and 76 respectively which restrict air flow inwards, e.g., a needle valve, but allows rapid egress of air from the low pressure side of the switch, e.g., a one way valve.
  • means 75 and 76 respectively which restrict air flow inwards, e.g., a needle valve, but allows rapid egress of air from the low pressure side of the switch, e.g., a one way valve.
  • variable volume cylinders 56, 57 Also connected to the low pressure side of each time switch 37 and 44 are variable volume cylinders 56, 57.
  • the effective capacity of the cylinders 56, 57 can be altered by movement of pistons 58 controlled by rotation of respective screw threaded rods 59 by knobs 60 to determine the time lapse between application of pressure to the low pressure input port and switch operation.
  • the mode selection switches, 32, 33, 34, 39, 40 and 41 and ON/OFF switch are lightly biased to the OFF position shown by spring means (not shown) and are manually operated. Such manual operation is facilitated by conversion of the small linear operation motion to rotary motion by the use of a cam having little difference between maximum and minimum radius.
  • the switches are grouped along a shaft 61 carrying cams so that the switches may be controlled, and the mode of operation of each period of the respirator selected, by rotating a single knob 62 as indicated by the broken lines connecting the switches with the shaft 61.
  • FIG. 1 for clarity, the movement of the diaphragm 45 and 48 of the sensors 46 and 49 is shown as being applied directly to operate the pressure mode switches 35 and 42.
  • the movement has to be amplifled; this may be done either by pneumatic amplifying means or by mechanical means or a combination of both.
  • the predetermined pressure levels at which the pressure mode switches and 42 operate is adjusted by altering the pneumatic amplification and/or the fulcrum 'point of a leverforming part of the linkage between the diaphragm andits pressure mode switch.
  • movement of a sensor relative to the linkage may form a part or the whole of the adjustment.
  • each switch 36 and 43 and lever 52, 54 being carried on a movable plate, indicated by a broken line 63 surrounding each switch and lever.
  • a very lightly spring loaded-one way valve 64- is connected between pipe 31 and controlport' 27 of valve 13 sothat, with pressure in-pipe, 31", the valve 64 is closed but, when the pipe 31 is vented viaair pipe 26, pressure from the control line 29 and control port 27 may escape through the one way, valve 64 and out throughport 9-of valve 16.
  • a similar valve 65 allowscontrol port 28 and control-pipe 30*to vent in the absence of pressure inpipe 38 through the one way valve 65 and port 25 of valve 16.
  • time modeswitehes37 and 44 are of atype, i.e., Kay Pneumatics Type KTD/023, in which no provision is made for sealingswitch port 66 shown as venting to atmosphere.
  • Compressed air from the high pressure source 8 passes along a pipe 11 through the ON/OFF switch 10 and the change-over valve 13 into pipe 14,.along pipe into the variable volume cylinder 57 through the low pressure inlet restriction 76 of mode switch 44.
  • the pressure in the cylinder 57 gradually increases at a rate dependent on the volume of the cylinder and the size of the restriction.
  • Compressed air from the source 8 also passes along pipe 17 and through change-over valve 16 into pipe 38 andprovides a biasing pressure against a piston 69 in the expiration time mode switch 44.-The piston 69 is connected to a piston 70 of larger area so that whenthe pressure in the cylinder 57.
  • gas passes from the source 8 through the valve 13 into'pipe 22 to operate change-over valve 16 which is exactly similar to change-over valve 13. Gas can then pass from the source 8 along pipe 17 andthrough valve 16 to pipe 26, pipe 20 being vented to atmosphere through port 25.
  • Gas thenalso passes from pipe 22 along pipe 54 into the variable volume 56 through the restriction in the entry to the low pressure side of the time mode switch
  • the time mode switch 37 operates in the same way as time mode switch 44.
  • gas passes from the source 8 along pipe 17, through valve 16 into pipes 26, along pipe 31, through selection switch 34, switch 37, one way valve 67, along control pipe 29 to the-port 27 of the change-over valve 13 to push the change-over member 71 back to the right as seen in FIG. 1'. on the, right side of piston device 74 is passed out to atmosphere through port 28, one way valve 65, pipe 38 and out through port 25 of change-over valve 16.
  • any of the other mode selection switches 32, 33, 39 or 40 are open as well or instead of selection switches 34 and 4]
  • operation of their respective mode switches 35, 36, 42 or 43 will allow gas to pass from pipe 31 to control pipe 29 or from pipe 38 to control pipe 30 thus causing the valve 13 to change-over immediately followed by change-over valve 16 changing over.
  • the pipes 20 and 26 controlling the respirator are thus alternately pressurised and vented to atmosphere in accordance with the operation of the mode switches.
  • the pneumatic control apparatus For the pneumatic control apparatus to function at least one of each of the sets of selection switches 32, 33 and 34 and 39, 40 and 41 must be open. When more than one of either of these sets of selection switches are open, the first of the selected mode switches to operate controls the change-over of the valve 13 and hence the termination of an inspiration or expiration period of the respirator.
  • This pneumatic control apparatus may be used with any multiple mode respirator requiring or using alternate presence and absence of gas pressure to control patient gas flow;
  • FIG. 2 shows an example of it being used with a respirator somewhat similar to that described in the aforementioned British Pat. specification No. 1 16215, working on closed circuit ventilation.
  • Three bellows 80, 81 and 82 have one side mounted on a fixed support 83 and the other side attached to a common movable striker bar 84 having a weight 85 on it biasing the bellows 80, 81 and 82 into their collapsed position.
  • the pipes 20 and 26 from the pneumatic drive circuit of FIG. 1 are connected to an inspiration control valve 86 and an expiration control valve 87. These control valves are spring-biassed to the open unless pressure is applied to the respective control pipe 20 or 26.
  • a driver gas is applied to a pipe 88 and passes via a one way valve 89 into bellows 80.
  • This driver gas may be compressed air supplied from the same source8 as that supplying the pneumatic control apparatus of FIG. 1.
  • inspiration control valve 86 is closed and seals a pipe 90 connected to the exit port of bellows 80 so that the latter expands.
  • expansion is transmitted to bellows 81, which is a negative pressure bellows, and also the third bellows 82 by the striker bar 84 to which all three bellows are attached.
  • air pipe 26 is vented (as previously described with reference to FIG. 1) and expiratory valve 87 is therefore open.
  • Gas then flows from the patient via pipe 91, a one way valve 92, a pipe 93, a valve 87 and a pipe 94 into bellows 81. Gas will not flow into bellows 81 via its exit port due to a one way valve 95 therein.
  • Patient gas at very low pressure applied to a pipe 96 initially charges a flexible walled reservoir bag 97 via a gas purifier 98 and during expiration gas will flow from the bag 97 into expanding bellows 82 through a one way valve 99 in its entry port, a one way valve 100 in the exit port of bellows 82 preventing gas entering therethrough.
  • the connection between the exit port of bellows 82 and the patient comprises a pipe 101, a flow control 102, a pipe 103, a diaphragm valve 104 and a pipe 105 lead to the mask for the patient.
  • the flow control 102 consists of a cylinder 108 having an entry port into which gas flows through pipe 101 from bellows 82. Gas then passes out through an exit port of flow control 102 into the pipe 103 through one I or more of a series of holes 109 of differing diameter in the cylnder 108. Rotation of a shaft 110 rotates the cylinder 108 and determines the number and size of holes 109 exposed to the exit port and therefore the flow rate.
  • pressurising and venting of air lines 20 and 26 has been reversed, so that valve 86 is open and valve 87 is closed. Opening of valve 86 allows gas pressure in bellows to drop and the weight moves the three bellows towards a collapsed condition.
  • the gas in bellows 81 passes through the one way valve in its exit port to a branch of pipe 96 to recharge bag 97 through the purifier 98.
  • gas in bellows 82 passes through the one way valve 100, pipe 101, flow control 102, pipe 103, diaphragm valve 104 and pipe 105 to inflate the lungs of the patient.
  • valve 99 is held closed so that no direct transfer of gas from bellows 81 to bellows 82 can occur and gas circulating from the patient passes through the purifier 98 twice, i.e., during charging and discharging of bag 97.
  • the patient gas supply connected to pipe 96 after initial charging of the gas circuit, serves to make up any losses in the system due to leakage and/or absorption by the patient.
  • the pipe 96 is connected to the bellows 81 through a one way valve in a third port (not shown) of the bellows 81 by a pressure conrol valve (not shown) which allows gas to pass from the bag 97 into the negative bellows 81 during expiration to control the negative pressure developed.
  • Pipes 106 and 107 branching from pipe 105, are connected to the pipes 47 and 50 of the positive and negative pressure sensors 46 and 49 respectively.
  • the one way valve 92 prevents gas flowing to the patient from the negative pressure bellows 81 should he attempt to inhale during an expiratory period. A lower pressure is more rapidly produced by the patient to operate the negative pressure sensor 49 connected to pipe 107, than if it was omitted.
  • the one way valve 92 instead of being in pipe 91, may alternatively be in the entry port of bellows 81 connected to pipe 94.
  • the pneumatic control apparatus of FIG. 1 and valves 86 and 87 of FIG. 2 may be used with a respirator which has all the other patient and driver gas components of the respirator described in the aforementioned British Pat. specification No. 1162151 to provide a pneumatically driven respirator having facilities for multiple mode cycling and manual. open, or closed circuit working.
  • the invention is not restricted to the details of the forgoing example.
  • change-over valve 16 may be omitted, the first air pipe 14 then being directly connected to air pipe 20 and second air pipe 22 to air pipe 26.
  • change-over valves 13 and 16 could take up a position in which air pressure in pipes 12 and 17 could not pass through the valves due to the position of shuttles 72, and the respirator would then be in a stalled condition and incapable of operation on reapplication of pressure.
  • Such a condition may be rectified by a switch arrangement (not shown) that allows pressure from line 12 to be temporarily applied to one of the control ports 27 or 28.
  • the switch arrangement is either arranged for manual operation or is mechanically linked to the switch to provide an automatic pulse of pressure to a control port on switching ON.
  • a multi-mode respirator having a pneumatically operated inspiration control valve, a pneumatically operated expiration control valve, bellow means in a patient gas path for measuring the volume of gas flowing to the patient and the volume of gas flowing from the patient, at least two of the following inspiratory and expiratory mode switches comprising: (a) inspiratory and expiratory volume mode pneumatic switches operatively connected to said bellow means to be operated by said bellow means respectively when the volume of gas flowing to the patientand the volume of gas flowing from the patient reaches predetermined magnitudes; (b) inspiratory and expiratory pressure mode pneumatic switches with pressure sensing means responsive to the pressure of inhaled and exhaled gas and operatively connected to said inspiratory and expiratory pressure mode switches to switch the inspiratory pressure mode switch when the pressure exceeds a predetermined value and to switch the expiratory pressure mode switch when the pressure falls below a predetermined value; and (c) inspiratory and expiratory time mode pneumatic switches each having a control input for pneumatic operation of the switch and each being connected to a separate
  • a pneumatic pressure source connected to the inputof said firstchange-over valve, a first pneumatic control circuit for said change-over valve, said first pneumatic control circuit including a pneumatic patient gas path having the inspiratory modeswitches each with its series selector switch in the respective gas flow paths connected in parallel'to one control input of the change-over valve, pneumatic pressure supply means for said first pneumatic control circuit comprising a supply connection from one outlet of said changeover valve or from a source controlled by that outlet, a second pneumatic control circuit for said changeover valve, said second control circuit including the expiratory mode switches, each with its series selector switch, connected in parallel to the second control input of said change-over valve, pneumatic pressure means for said second pneumatic control circuit comprising a supply connection from the second outlet of the change-over valve or from a source controlled by that outlet, means applying pressure from said first and said second
  • a multi-mode respirator having a pneumatically operated inspiration control valve, a pneumatically operated expiration control valve, bellow means in a patient gas path for measuring the volume of gas flowing to the patient and the volume of gas flowing from the patient, inspiratory and expiratory volume mode pneumatic switches operatively connected to said bellow means to be operated by said bellow means respectively when the volume of gas flowing to the patient and the volume of gas flowing from the patient reaches predetermined magnitudes, inspiratory and expiratory pressure mode pneumatic switches, pressure sensing means responsive to the pressure of inhaled and exhaled gas and operatively connected to said inspiratory and expiratory pressure mode switches to switch the inspiratory pressure mode switch when the pressure ex ceeds a predetermined value and to switch the expiratory pressure mode switch when the pressure falls below a predetermined value, inspiratory and expiratory time mode pneumatic switches each having a control input for pneumatic operation of the switch and each being connected to a separate pneumatic delay including a piston operated through a restricted orifice whereby each time switch operates it a
  • said change-over valve comprises a cylinder having a main inlet and two outlets and a valve-changeover member including a shuttle member connected between two piston devices slidable within a cylinder, the shuttle member being arranged to move across said main inlet between the two outlets to connect the main inlet to one or other of the two outlets and wherein two venting outlets are provided in the cylinder and controlled by movement of the piston devices respectively.
  • each control inlet of the change-over valve device is connected through a non-return valve to a controlled vent to atmosphere.
  • each said pneumatic delay includes a piston operated through a restricted orifice and wherein the appropriate output of the first change-over valve is fed to the time delay and wherein the outputs of the further change-over valve are connected to the appropriate switch devices to provide the flow therethrough.

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  • Health & Medical Sciences (AREA)
  • Emergency Medicine (AREA)
  • Pulmonology (AREA)
  • Engineering & Computer Science (AREA)
  • Anesthesiology (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Hematology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Respiratory Apparatuses And Protective Means (AREA)
US00072349A 1969-09-15 1970-09-15 Cyclically operated medical respirators Expired - Lifetime US3754550A (en)

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Cited By (22)

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US3889669A (en) * 1972-12-11 1975-06-17 Puritan Bennett Corp Respiration rate control system
US3916889A (en) * 1973-09-28 1975-11-04 Sandoz Ag Patient ventilator apparatus
US3949749A (en) * 1974-02-24 1976-04-13 Bio-Med Devices Inc. Pediatric respirator
US3957047A (en) * 1974-02-08 1976-05-18 Dragerwerk Aktiengesellschaft Respiration-time control device in respirators for infants
US3974828A (en) * 1975-01-27 1976-08-17 Bird F M Ventilator and method
US4007736A (en) * 1975-03-12 1977-02-15 N.A.D., Inc. Fluidic controlled ventilator
US4057059A (en) * 1975-07-29 1977-11-08 Oklahoma State University Intermittent positive pressure breathing device
US4067328A (en) * 1975-07-29 1978-01-10 The Medishield Corporation Limited Lung ventilator
US4096858A (en) * 1975-01-29 1978-06-27 Chemetron Corporation Volume-rate respirator system and method
USRE29778E (en) * 1974-06-07 1978-09-26 Bio-Med Devices, Inc. Pediatric respirator
US4227519A (en) * 1977-08-06 1980-10-14 Dragerwerk Aktiengesellschaft Respirator for emergency air supply to a patient
US4340044A (en) * 1980-03-20 1982-07-20 Berkshire Research Partners Volume ventilator
US4351329A (en) * 1980-11-06 1982-09-28 Bear Medical Systems, Inc. High frequency breath pump
US4381002A (en) * 1980-12-18 1983-04-26 The United States Of America As Represented By The Secretary Of The Army Fluidic-controlled oxygen intermittent demand flow device
US4471775A (en) * 1982-09-07 1984-09-18 Clair Michael W Endotracheal tube cuff synchronizing system
US4782831A (en) * 1986-05-27 1988-11-08 Gallant John H Volume-controlled manual resuscitator
US4928683A (en) * 1987-02-17 1990-05-29 Bart Westerkamp Respirating apparatus for patients
US20040107964A1 (en) * 2001-04-12 2004-06-10 Shaw Geoffrey Mark Continuous positive airway pressure device
US20140150786A1 (en) * 2012-12-05 2014-06-05 Mindray Ds Usa, Inc. Power switch for auxiliary common gas outlet
US20140261429A1 (en) * 2013-03-13 2014-09-18 Chi-Sheng Tsai Oxygen-supplying respirator requiring no electric power
US20210338952A1 (en) * 2020-05-01 2021-11-04 Groman Inc. Two pneumatic cylinder medical ventilator, system and method
CN117919618A (zh) * 2024-03-22 2024-04-26 山西锦丰大地精密机械有限公司 一种矿用呼吸防护装置

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DE3823382C1 (2) * 1988-07-09 1990-01-11 Draegerwerk Ag, 2400 Luebeck, De
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US3889669A (en) * 1972-12-11 1975-06-17 Puritan Bennett Corp Respiration rate control system
US3916889A (en) * 1973-09-28 1975-11-04 Sandoz Ag Patient ventilator apparatus
US3957047A (en) * 1974-02-08 1976-05-18 Dragerwerk Aktiengesellschaft Respiration-time control device in respirators for infants
US3949749A (en) * 1974-02-24 1976-04-13 Bio-Med Devices Inc. Pediatric respirator
USRE29778E (en) * 1974-06-07 1978-09-26 Bio-Med Devices, Inc. Pediatric respirator
US3974828A (en) * 1975-01-27 1976-08-17 Bird F M Ventilator and method
US4096858A (en) * 1975-01-29 1978-06-27 Chemetron Corporation Volume-rate respirator system and method
US4007736A (en) * 1975-03-12 1977-02-15 N.A.D., Inc. Fluidic controlled ventilator
US4069818A (en) * 1975-03-12 1978-01-24 N.A.D., Inc. Fluidic controlled ventilator
US4057059A (en) * 1975-07-29 1977-11-08 Oklahoma State University Intermittent positive pressure breathing device
US4067328A (en) * 1975-07-29 1978-01-10 The Medishield Corporation Limited Lung ventilator
US4227519A (en) * 1977-08-06 1980-10-14 Dragerwerk Aktiengesellschaft Respirator for emergency air supply to a patient
US4340044A (en) * 1980-03-20 1982-07-20 Berkshire Research Partners Volume ventilator
US4351329A (en) * 1980-11-06 1982-09-28 Bear Medical Systems, Inc. High frequency breath pump
US4381002A (en) * 1980-12-18 1983-04-26 The United States Of America As Represented By The Secretary Of The Army Fluidic-controlled oxygen intermittent demand flow device
US4471775A (en) * 1982-09-07 1984-09-18 Clair Michael W Endotracheal tube cuff synchronizing system
US4782831A (en) * 1986-05-27 1988-11-08 Gallant John H Volume-controlled manual resuscitator
US4928683A (en) * 1987-02-17 1990-05-29 Bart Westerkamp Respirating apparatus for patients
EP1383564A4 (en) * 2001-04-12 2005-10-05 Lifevent Ltd POSITIVE AIR CONTINUOUS AIR PRESSURE DEVICE
US20040107964A1 (en) * 2001-04-12 2004-06-10 Shaw Geoffrey Mark Continuous positive airway pressure device
US7284554B2 (en) 2001-04-12 2007-10-23 Lifevent Limited Continuous positive airway pressure device
US20140150786A1 (en) * 2012-12-05 2014-06-05 Mindray Ds Usa, Inc. Power switch for auxiliary common gas outlet
US9913957B2 (en) * 2012-12-05 2018-03-13 Shenzhen Mindray Bio-Medical Electronics Co. Ltd. Power switch for auxiliary common gas outlet
US20140261429A1 (en) * 2013-03-13 2014-09-18 Chi-Sheng Tsai Oxygen-supplying respirator requiring no electric power
US20210338952A1 (en) * 2020-05-01 2021-11-04 Groman Inc. Two pneumatic cylinder medical ventilator, system and method
CN117919618A (zh) * 2024-03-22 2024-04-26 山西锦丰大地精密机械有限公司 一种矿用呼吸防护装置
CN117919618B (zh) * 2024-03-22 2024-05-31 山西锦丰大地精密机械有限公司 一种矿用呼吸防护装置

Also Published As

Publication number Publication date
SE378757B (2) 1975-09-15
FR2061396A5 (2) 1971-06-18
GB1328087A (en) 1973-08-30
DE2045494A1 (de) 1971-03-25

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