AUTOMATIC RESPIRATOR

• US 3,753,436 A
• Filed: 02/16/1971
• Issued: 08/21/1973
• Est. Priority Date: 04/06/1970
• Status: Expired due to Term

• Current Assignee: Forrest M. Bird, Henry L. Pohndorf
• Original Assignee: Forrest M. Bird, Henry L. Pohndorf
• Inventors: Bird, Forrest M., Pohndorf, Henry L.
• Primary Examiner(s): Gaudet, Richard A.
• Assistant Examiner(s): Dunne, G. F.
• Application Number:
  US05/115,225
• Time in Patent Office: 917 Days
• Field of Search: 128/145.8,145.5-145.7,142-142.4,145,146,185,186,191,195,194
• US Class Current: 128/204.19
• CPC Class Codes: A61M 16/0063 Compressors
• CPC Class Codes: A61M 16/021 operated by electrical means A61M16/202 – A61M16/205 take precedence
• CPC Class Codes: A61M 16/0858 Pressure sampling ports

Abstract

Respiratory apparatus for controlling the flow of gases to a patient'"'"''"'"'s airway. In one embodiment a light weight, portable, reliable and ethical respirator apparatus adapted for home use or the like is provided. A servo flow control affords convenient and accurate adjustment of sensitivity pressures and peak inspiratory pressures. The elements are constructed in a manner facilitating disassembly, sterilization, and assembly by a relatively unskilled person. The respirator is adapted to freely operate under adverse conditions without being affected by an accumulation of moisture. In another embodiment the respirator apparatus includes means facilitating accurate manual adjustment of the peak inspiratory pressure limit in a manner which does not alter the pre-set sensitivity level.

Claims

1. In a respiratory apparatus having an inspiratory phase and an expiratory phase in its operative cycle, the combination including:

a control valve body having an inlet adapted to be connected to a source of gas under pressure, an outlet for communicating a mainstream flow of gas to the airway of a patient, and a valve seat between said inlet and outlet;

a valve element movable from an open position spaced from the valve seat to establish communication between the inlet and outlet for the inspiratory phase, and to a closed position occluding said valve seat to interrupt said communication between the inlet and outlet for the expiratory phase;

valve operating means including a shaft having a large mass relative to the mass of said valve element, said shaft being movable between a first position to strike said valve element and urge the same to its open position, and to a second position releasing said valve element permitting movement thereof to its closed position, said valve operating means including pressure responsive means urging said shaft between said first and second positions responsive to pressure of the gas communicating with the airway of the patient;

a magnet mounted within said valve body;

sensitivity pressure adjusting means including an armature spaced from one end of the magnet and creating a magnetic force therewith tending to urge the shaft to its second position, sais sensitivity adjusting means including means to vary said magnetic force for adjusting the sensitivity pressure in the pressure responsive means which is effective to move the shaft to the first position; and

, peak inspiratory pressure adjusting means including an armature spaced from the opposite end of the magnet and creating a magnetic force therewith tending to urge the valve operating means to its first position, said peak inspiratory adjusting means including means to vary said magnetic force for adjusting the peak inspiratory pressure in the pressure responsive means which is effective to move the shaft to the second position.

2. In a respiratory apparatus having an inspiratory phase and an expiratory phase in its operative cycle, the combination including:

a control valve body having an inlet adapted to be connected to a source of gas under pressure and an outlet for communicating a mainstream flow of gas to the airway of a patient;

a valve element movable between an open position establishing communication between the inlet and outlet for the inspiRatory phase, and to a closed position interrupting said communication between the inlet and outlet for the expiratory phase;

valve operating means including an axially sliding shaft mounted in said control valve body, said shaft being movable between a first position urging said valve element to its open position, and to a second position releasing said valve element permitting movement thereof to its closed position, said valve operating means further including pressure responsive means comprising diaphragm means in operating relationship with said shaft and defining a chamber in communication with said mainstream flow to the patient, said chamber being provided with openings for exhausting gases to atmosphere during said expiratory phase, and to close said chamber during the inspiratory phase, and including one-way valve means allowing only exhaust flow through said openings from the chamber, said shaft including a stub portion extending into the chamber together with valve means slidably mounted on said shaft stub portion within the chamber to close said chamber openings during the inspiratory phase;

lost-motion connection means between said valve means and shaft stub portion, said lost-motion connection means being arranged to provide a first excursion of said shaft stub portion upon initiation of said expiratory phase without moving said valve means from its closed position with said openings, and a second excursion of said shaft stub portion moving said valve means to its closed position after said shaft builds up momentum;

sensitivity pressure adjusting means including an armature spaced from one end to the magnet and creating a magnetic force therewith tending to urge the valve operating means to its second position, said sensitivity adjusting means including means to vary said magnetic force for adjusting the sensitivity pressure in the pressure responsive means which is effective to move the valve operating means to the first position; and

, peak inspiratory pressure adjusting means including an armature spaced from the opposite end of the magnet and creating a magnetic force therewith tendin to urge the valve operating means to its first position, said peak inspiratory adjusting means including means to vary said magnetic force for adjusting the peak inspiratory pressure in the pressure responsive means which is effective to move the valve operating means to the second position.

3. In a respiratory apparatus having an inspiratory phase and an expiratory phase in its operative cycle, the combination including:

a control valve body having an inlet adapted to be connected to a source of gas under pressure and an outlet for communicating a mainstream flow of gas to the airway of a patient;

a valve element movable from an open position establishing communication between the inlet and outlet for the inspiratory phase, and to a closed position interrupting said communication between the inlet and outlet for the expiratory phase;

valve operating means movable between a first position urging said valve element to its open position, and to a second position releasing said valve element permitting movement thereof to its closed position, said valve operating means including pressure responsive means urging said valve operating means between said first and second positions responsive to pressure of the gas communicating with the airway of the patient;

a magnet mounted within said control valve body adjacent said valve operating means;

sensitivity pressure adjusting means including an armature spaced from one end of the magnet and comprising a body of metal for creating a magnetic force with said magnet, said metal body being mounted for movement with said valve operating means and tending to urge the valve operating means to its second position, said sensitivity adjusting means including means to vary said magnetic force for adjusting the sensitivity pressure in the pressure responsive means which is effective to move the valve operating means to the first position; and

, peak inSpiratory pressure adjusting means including an armature spaced from the opposite end of the magnet and comprising a body of metal for creating a magnetic force with said magnet, said metal body being mounted for movement with said valve operating means and tending to urge the valve operating means to its first position, said peak inspiratory adjusting means including means to vary said magnetic force for adjusting the peak inspiratory pressure in the pressure responsive means which is effective to move the valve operating means to the second position.

4. The invention of claim 3 and further characterized in that said means to vary the magnetic force for said sensitivity adjusting means includes a first externally threaded shaft mounted for movement with said valve operating means, said sensitivity adjusting means includes a sensitivity wheel threadably mounted on said shaft for axial displacement upon rotation thereof, said means to vary the magnetic force for the pressure adjusting means includes a second externally threaded shaft mounted for movement with the valve operating means, and said pressure adjusting means includes a pressure wheel threadably mounted on said shaft for axial displacement upon rotation thereof.

5. The invention of claim 4 and further characterized in that means are provided to releasably hold both the sensitivity adjusting means wheel and pressure adjusting means wheel against relative rotation with respect to the respective threaded shafts.

6. The invention of claim 4 and further characterized in that the first and second threaded shafts are formed with respective selective thread pitches effective to establish a fixed differential in magnetic force of inspiratory effort when said sensitivity and pressure wheels are rotated to preselected positions.

7. The invention of claim 6 and further including releasable jaw means to constrain said first and second shafts against relative rotation, said jaw means upon release adapted to permit relative rotation of said shafts to provide selective adjustment of the said fixed differential.

8. For use in a respiratory apparatus having a source of pressurized air, means to control the rate of air flow from the source of air pressure, and a breathing head assembly adapted to provide a mainstream flow of said air to a patient, the combination including:

a servo control valve body mounted on said breathing head assembly, said valve body including an inlet in communication with said source of air pressure and an outlet in communication with said mainstream flow in the breathing head assembly;

phase control valve means mounted with said body and including a valve element movable to an open position to direct air flow between the inlet and outlet for an inspiratory operating phase, and to a closed position closing said communication during an expiratory operating phase;

shaft means mounted in said body for movement between a first position urging said valve element to its open position, and to a second position releasing said valve element for movement thereof to its closed position, said shaft means being positioned in said body out of the gas flow circuit between said inlet and outlet;

expansible chamber means in communication with said mainstream of the breathing head assembly and operable to move said shaft means to its first position responsive to a predetermined sensitivity pressure in said mainstream flow to initiate said inspiratory phase, and further operable to move the shaft means to its second position responsive to a predetermined peak inspiratory pressure in said mainstream to initiate said expiratory cycle.

9. The invention of claim 8 and further characterized in that said expansible chamber includes one-way valve means to direct exhalation gas from said mainstream passage to the atmosphere through the chamber, second valve means to occlude said exhaust one-way valve means during the inspiratory phase, and valve operating means on the shaft means operably connected with said second vAlve means to move the latter to open position during the expiratory phase.

10. The invention in claim 9 and further characterized in that the shaft means includes a shaft end extending into the expansible chamber, said second valve means being slidably mounted on said shaft end, and said shaft end including a valve operating projection engaging the second valve means after an initial excursion of the shaft means.

11. The invention of claim 8 and further characterized in that said phase control valve means includes a valve body provided with a valve bore communicating between said inlet and outlet, one end of said valve bore defining a valve seat, and said valve element is slidably mounted in said valve bore and includes a valve head seating against said valve seat in the closed position of the valve element.

12. The invention of claim 11 and further characterized in that said valve element head defines an outwardly flaring end providing a substantially line-contact engagement with said valve seat, said air pressure from the inlet acts against said valve head to urge the valve element to its closed position during said expiratory phase.

13. The invention of claim 11 and further characterized in that said valve element includes an elongate stem having an end projecting from said valve body, said shaft means including a valve operating member in registry with said valve stem to move the valve element to its open position when the shaft means moves to its first position, and to move out of registry with the valve stem in the second position of the shaft means whereby air pressure from the inlet is effective to urge the valve element to its closed position.

14. In a respiratory apparatus having an inspiratory phase and an expiratory phase in its operative cycle, the combination including a control valve body having an inlet adapted to be connected to a source of gas under pressure and an outlet for communicating a mainstream flow of gases to the airway of a patient, a valve element movable from an open position establishing communication between the inlet and outlet for the inspiratory phase, and to a closed position interrupting said communication between the inlet and outlet for the expiratory phase, valve operating means movable between a first position urging said valve element to its open position, and to a second position releasing said valve element permitting movement thereof to its closed position, said valve operating means including pressure responsive means urging said valve operating means between said first and second positions responsive to pressure of the gas communicating with the airway of the patient, means in the valve body creating a magnetic field, sensitivity pressure adjusting means urging the valve operating means to its first position responsive to said magnetic field, and means in association with said valve operating means to selectively limit the excursion of the same toward said first position and thereby selectively vary the limit of peak inspiratory pressure.

15. In a respiratory apparatus as in claim 14 wherein the valve operating means includes an extension at one end thereof, and said means limiting the excursion of the valve operating means includes an end member positioned to limit the outward excursion of the valve operating extension together with means to selectively vary said position of the end member with respect to the valve operating means.

16. A respiratory apparatus as in claim 15 wherein the valve operating means extension projects from an end of the valve body, and the end member comprises a cap mounted on the valve body and being formed with a central opening through which the extension projects to facilitate manual grasping thereof for manual cycling of the control valve.

17. A respiratory apparatus as in claim 15 wherein the end member comprises a cap threadably mounted on the valve body whereby selective turning of the cap varies the displacement thereof with respect to the extension of the valve opeRating means.

18. A respiratory apparatus as in claim 17 in which the cap is formed with a central opening through which said extension projects, and an annular detent is provided on said extension for engagement with the cap adjacent said opening to limit said outward excursion of the valve operating means.

19. A respiratory apparatus as in claim 18 in which said cap central opening is formed with an inwardly diverging walls and said annular detent comprises an O-ring mounted on said extension and adapted for engaging the opening walls to limit outward excursion of the valve operating means.

20. A respiratory apparatus as in claim 14 in which the sensitivity pressure adjusting means comprises a first armature mounted on the valve operating means and axially adjustable therewith to selectively vary its attraction force from the magnetic field, and the inspiratory pressure adjusting means comprises a second armature mounted on the valve operating means and axially adjustable therewith to selectively vary its attraction force from the magnetic field.

21. A respiratory apparatus as in claim 20 including a magnet creating said magnetic field, the magnet being positioned in the valve body between said first and second armatures.

22. A respiratory apparatus as in claim 14 wherein said pressure responsive means is adapted for branch connection with the mainstream flow of gases in a breathing head assembly connectable with a patient'"'"''"'"'s airway.