PRESSURE ALTERNATING DEVICE FOR AUTOMATIC LUNGS VENTILATOR ACTUATION

• US 3,658,443 A
• Filed: 11/20/1970
• Issued: 04/25/1972
• Est. Priority Date: 11/21/1969
• Status: Expired due to Term

• Current Assignee: Giovanni Fumagalli
• Original Assignee: Giovanni Fumagalli
• Inventors: Fumagalli, Giovanni
• Primary Examiner(s): Walker, Robert M.
• Application Number:
  US05/091,250
• Time in Patent Office: 522 Days
• Field of Search: 417/384,385,388,394,395
• US Class Current: 417/384
• CPC Class Codes: A61M 16/0009 with sub-atmospheric pressure, e.g. during expiration
• CPC Class Codes: A61M 16/0057 Pumps therefor
• CPC Class Codes: A61M 16/0063 Compressors
• CPC Class Codes: A61M 16/20 Valves specially adapted to medical respiratory devices
• CPC Class Codes: A61M 16/202 electrically actuated
• CPC Class Codes: A61M 16/206 Capsule valves, e.g. mushroom, membrane valves

Abstract

The device is designed for alternatingly supplying air at superatmospheric and respectively at subatmospheric pressure into a variable pressure chamber of a lungs ventilator for pulsingly and meteredly supplying fresh gas into a patient'"'"''"'"'s lungs. The device comprises a pump having a rotary piston adapted to unidirectionally and pulsingly feeding air at a rate whose variation in each pulse is substantially defined by the function of '"'"''"'"''"'"''"'"'sin2 alpha'"'"''"'"''"'"''"'"' ('"'"''"'"''"'"''"'"'alpha'"'"''"'"''"'"''"'"' being the amplitude of the rotational motion), and a negative pressure limiting valve including a valve member electromagnetically biased by a biasing force which decreases with the second power of the displacement of said member, to provide a venting passage the cross-sectional area of which varies concurrently with the speed of air through said passage for levelling the variable resistance encountered by said air traversing said passage at different speeds.

Claims

1. A pressure alternating device for actuating an apparatus for automatic ventilation of lungs, said apparatus including a variable pressure chamber wherein air at superatmospheric and at subatmospheric pressure is to be alternatingly supplied for promoting a pulsing feeding of fresh gas to a patient'"'"''"'"'s lungs in given amounts and positive pressure and at an adjustable respiratory frequency, comprising a pumping assembly adapted to provide alternated pulsing in-flows and out-flows, the negative and respectively positive pressure levels in and the rates of said flows gradually increasing at each pulsing cycle, duct means connecting said pumping assembly to said apparatus chamber, and negative prEssure limiting valve means connected to vent said duct means and chamber to atmosphere, said valve means comprising a valve member movable against a biasing force for opening a venting passage when a given negative pressure level is attained, and means to apply to said valve member a biasing force decreasing as the cross-sectional area of said venting passage increases.

2. The device of claim 1, wherein electromagnetical means are provided to apply a biasing force tending to close said venting passage, said biasing force decreasing as a function of the second power of the amplitude of the motion of said valve member, said amplitude defining the said cross-sectional area of said venting passage.

3. The device of claim 1, wherein the said pumping assembly comprises a rotary pump adapted for providing an unidirectional pulsing flow at each complete 360* revolution of its rotary components from an inlet and an outlet thereof, and a distributing valve phasedly and timedly connected to said rotary components to alternatingly connect said inlet and respectively said outlet to said duct means and said variable pressure chamber of said apparatus.

4. The device of claim 3, wherein said rotary pump comprises a rotary piston eccentrically revolved within a chamber formed into a stationary casing, to provide a pulsing in-flow and out-flow, at each 360* revolution of said piston, at a flow rate varying according to a function of the type '"'"''"'"''"'"''"'"'sin2 alpha'"'"''"'"''"'"''"'"' (wherein '"'"''"'"''"'"''"'"'alpha'"'"''"'"''"'"''"'"' is the amplitude of rotary motion), and wherein the said distributing valve is connected to said pump for discontinuing the applying of said flows to said variable pressure chamber of the apparatus after a 240* about revolution of said piston, beginning from the position at which the rate of flow is about null.

5. The device of claim 4, wherein the said rotary pump comprises a casing having a cylindrical chamber formed thereinto, a shaft rotatively and drivedly supported in said chamber and having an eccentric formed therewith, a cylindrical piston body rotatively sopported about said eccentric and dimensioned for essentially contact the inner wall of said cylindrical chamber sequentially at any point thereof as said eccentric performs a 360* revolution about the axis of said shaft, a partition wall oscillatably connected to said casing at a line parallel to the axis thereof, extending inwardly in said cylindrical chamber and slidably engaged into a radial groove formed in said cylindrical piston body, and inlet and outlet ports formed in said chamber adjacent to and at either sides of said partition wall and each individually communicating with the variable volume spaces formed in said chamber about said piston body and divided by said partition wall and by the line at which said piston body actually contacts said inner wall of said cylindrical chamber.

6. The device of claim 4, wherein the said distributing valve comprises an essentially cylindrical distributing member rotatably housed into a casing having diametrally opposed ports connected to inlet and respectively to outlet of the said rotary pump, and other ports at 90* from said former ports, one of said other ports being connected to the said variable pressure chamber of the apparatus, symmetrical recesses formed in said distributing member for connecting pairs of ports at 90* from each other, and comprising drive means for steppingly rotating said member for alternatingly positioning said member so that one of said recesses alternatingly connects said other one port to the port connected to the outlet and respectively to the inlet of the pump, at each second revolution of the rotary components of the pump.

7. The device of claim 2, wherein the said electromagnetical means comprise an energizable coil and a pole piece, the said valve member is connected to a ferrous element magnetically attracted by said pole piece to provide the said biasing force, said pole piece being adjustably secured to said coil for adjustment of its spacing from said ferrous element when the valve is closed.

8. A device for alternatingly supplying a negative and a positive pressure to the variable pressure chamber of a known apparatus for automatic ventilation of a patient'"'"''"'"'s lungs, for pulsingly promoting the supply of fresh gas to the patient at a given pressure and rate and at an adjustable frequency or respiratory cycle, comprising, in combination:

i. a pumping device of rotary type and comprising variable volume chambers whose volumes vary, at each complete revolution of 360* of its rotary components, substantially in accordance with a function of the type '"'"''"'"''"'"''"'"'sin2 alpha'"'"''"'"''"'"''"'"', wherein '"'"''"'"''"'"''"'"'alpha'"'"''"'"''"'"''"'"' is the amplitude of the rotational motion, and comprising inlet and outlet ports wherethrough a pulsing in-flow and respectively out-flow are promoted at said each complete revolution;

ii. a distributing valve phasedly and timedly connected to said pump rotary components, connected to said inlet port, to said outlet port, to a venting port and to the said apparatus variable pressure chamber, and such to alternatingly connecting said inlet port and said outlet port to said chamber at each second complete revolution of the said rotary components of the pumping device; and

iii. a negative pressure level limiting valve connected to said variable pressure chamber, comprising a valve member movable relatively to a valve seat to provide a spacing therebetween for venting said space to atmosphere when the valve opens against a biasing force exerted by an electromagnetic device which provides a biasing force, urging said valve member towards said valve seat, which decreases according to a function of the second power of said spacing, to compensate for the variable resistance encountered by the air passing through the passage provided between the spaced valve member and seat, at different speeds resulting from different durations of the times in which the said negative pressure is increasingly applied into said variable pressure chamber.

9. The device of claim 8, wherein the said rotary pumping device comprises a casing having a cylindrical chamber formed thereinto, a shaft rotatively and drivedly supported in said chamber and having an eccentric formed therewith, a cylindrical piston body rotatively supported about said eccentric and dimensioned for essentially contact the inner wall of said cylindrical chamber sequentially at any point thereof as said eccentric perform a 360* revolution about the axis of said shaft, a partition wall oscillatably connected to said casing at a line parallel to the axis thereof, extending inwardly in said cylindrical chamber and slidably engaged into a radial groove formed in said cylindrical piston body, and inlet and outlet ports formed in said chamber adjacent to and at either sides of said partition wall and each individually communicating with the variable volume spaces formed in said chamber about said piston body and divided by said partition wall and by the line at which said piston body actually contacts said inner wall of said cylindrical chamber.

10. The device of claim 8, wherein the said distributing valve comprises an essentially cylindrical distributing member rotatably housed into a casing having diametrally opposed ports connected to inlet and respectively to outlet of the said rotary pumping device, and other ports at 90* from said former ports, one of said other ports being connected to the said variable pressure chamber of the apparatus, symmetrical recesses formed in said distributing member for connecting pairs of ports at 90* from each other, and comprising drive means for steppingly rotating said member for alternatingly positioning said member so that one of said recesses alternatingly connected said other one port to the port connected to the outlet and respectively to the inlet of the pump, at each second revolutIon of the rotary components of the pump.

11. The device of claim 8, wherein the said electromagnetical device comprise an energizable coil and a pole piece, the said valve member is connected to a ferrous element magnetically attracted by said pole piece to provide the said biasing force, said pole piece being adjustably secured to said coil for adjustment of its spacing from said ferrous element when the valve is closed.