Pressure monitor for a lung ventilator

Claim 2

A fully pneumatic pressure monitor for a lung ventilator having a supply of breathing gas under pressure and an airway conduit for connection to a patient, including in combination: a pressure regulator adapted to be connected to said supply, pneumatically-operated warning means, pneumatic airway pressure sensing means adapted to be connected to a said airway conduit for sensing the pressure therein, a low-limit detector pneumatically connected to said airway pressure sensing means and having a valve that it opens when said airway pressure is above a predetermined low limit, as it should be during the inspiratory phase of the ventilator''s breathing cycle, gas flow metering means connected to said regulator for supplying gas at a predetermined flow rate, pneumatically-operated timing means connected to said gas flow metering means and having a control valve connected to said pressure regulator and that opens when the gas from said metering means builds up to a predetermined pressure level within said timing means, said timing means having means for sending a flow signal from said pressure regulator to said warning means when said control valve is opened, said timing means being connected to said valve of said lowlimit detector, whereby if said valve of said low-limit detector opens before said control valve is opened, the pressure buildup from said metering means is bled off through said valve of said low-limit detector and said control valve does not open, a high-limit detector pneumatically connected to said airway pressure sensing means and having a valve that opens when the airway pressure exceeds a predetermined high limit, high-limit pneumatic switch means pneumatically connected to said regulator and having an open position wherein actuating gas from said regulator is sent to said warning means and haviNg a closed position wherein no such gas under pressure is sent, and pneumatic means connected to said regulator, to said switch means and to said valve of said high-limit detector, for normally holding said switch means closed except when the valve of said high-limit detector is open to bleed said pneumatic means.

Claim 3

The monitor of claim 1 wherein said timing means has means for interrupting its said flow signal so that the signal causes the warning means to go on and off rapidly in alternation and with approximately equal times on and off, so long as the airway pressure is below said predetermined low limit.

Claim 4

means in said timing means for interrupting its said pressure signal and thereby produce an interrupted alarm while said airway pressure is below said predetermined level, and

Claim 5

means in said timing means for interrupting its said pressure signal and thereby produce an interrupted alarm while said airway pressure is below said predetermined level, and

Claim 6

means in said high-limit detector for causing its said pressure signal to provide a long on period followed by a long off period corresponding approximately to a patient breathing cycle.

Claim 7

means in said high-limit detector for causing its said pressure signal to provide a long on period followed by a long off period corresponding approximately to a patient breathing cycle.

Claim 8

The monitor of claim 1 wherein said timing means has means for interrupting its said flow signal so that the signal causes the warning means to go on for a short period then off for a much longer period in alternation so long as said airway pressure remains below said predetermined low limit.

Claim 9

The monitor of claim 1 having: supply pressure detector means having an inlet adapted to be connected to said supply pressure and an outlet connected to said warning means, means for closing off said outlet from said inlet when said supply pressure is above a predetermined level, and means for opening said outlet for passage of gas from said inlet to said warning means when said supply pressure drops below a predetermined level.

Claim 10

The monitor of claim 4 wherein the warning signals are differentiated as to the cause of the warning by apparatus, as follows:

Claim 11

The monitor of claim 4 wherein said supply pressure detector means comprises a diaphragm and a housing providing a chamber with the inlet thereinto being the inlet adapted to be connected to said supply pressure and the outlet therefrom the one connected to said warning means, said diaphragm actuating a normally closed poppet valve serving as part of said means for closing off and having spring means serving as part of said means for opening, urging said diaphragm to open said poppet valve when the pressure in said chamber drops below a predetermined value.

Claim 12

The pressure monitor of claim 1 having: a flow control valve having an inlet connected to said regulator and an outlet for gas at a constant rate of flow, conduit means connected to said outlet of said flow control valve and connected to said airway pressure sensing means, said low-limit detector, and said high-limit detector, said airway pressure sensing means comprising a housing and a diaphragm dividing said housing into first and second chambers, said first chamber being adapted for connection to said airway conduit, said second chamber being connected to said conduit means and having an orifice connected to atmosphere, the passage from said second chamber to said orifice being determined by the position of said diaphragm relative to said orifice, whereby the pressure in said conduit means is maintained at the pressure of a said airway conduit when said first chamber is connected thereto, said diaphragm isolating said airway conduit from said conduit means.

Claim 13

The pressure monitor of claim 7 wherein said low-limit detector comprises a housing and a diaphragm providing a third chamber with an inlet connected to said conduit means and a passage with a nozzle, seal means mounted to said diaphragm, and spring means urging said diaphragm to force said seal means to close against said nozzle except when the pneumatic pressure in said third chamber is Great enough to overcome the pressure exerted by said spring means, said nozzle and seal means comprising said valve of said low-limit detector.

Claim 14

The pressure monitor of claim 8 wherein said pneumatically operated timing means comprises a housing and a diaphragm assembly with two diaphragms providing fourth, fifth, and sixth chambers, said first diaphragm having a smaller effective area than said second diaphragm and lying between said fourth and fifth chambers, while said second diaphragm lies between said fifth and sixth chambers, said fourth chamber having an inlet connected to said pressure regulator and having an outlet with a sized restricted passage, said diaphragm assembly carrying a seal and having spring means for urging said seal to close said inlet, said seal and said inlet constituting said control valve, orifice means connecting said fourth chamber to said sixth chamber for timed release of gas from said fourth chamber to build up pressure in said sixth chamber aiding in urging said seal to close, said fifth chamber being connected to the outlet of said gas flow metering means.

Claim 15

The pressure monitor of claim 7 wherein said high-limit detector comprises a housing and a diaphragm providing a chamber connected to said conduit means and a nozzle, seal means mounted to said diaphragm and, together with said nozzle, constituting said valve of said high-limit detector, said valve means having an inlet of said nozzle connected to said pneumatic means, spring means urging said diaphragm to force said seal means to close said nozzle except when the pneumatic pressure in its said chamber is great enough to overcome the pressure exerted by said spring means, said pneumatic means having a small orifice with its inlet connected to said regulator and its outlet connected to said nozzle inlet and acting on said high-limit switch so that when said nozzle is sealed closed, said pneumatic means reaches the outlet pressure of said regulator and holds said high-limit switch closed, and the outlet pressure of said pneumatic means drops to the conduit means pressure when said nozzle is opened.

Claim 16

The pressure monitor of claim 10 wherein said high-limit pneumatic switch means comprises a housing and a diaphragm providing two chambers, one said chamber being connected to the outlet from said small orifice and forming part of said pneumatic means, the other said chamber having an inlet with a sized restricted passage connected to said pressure regulator and an outlet also having a sized restricted passage, this said diaphragm closing off said inlet when the pressure in said one said chamber is substantially equal to that of said regulator outlet and opening said inlet for flow of gas to the outlet when the pressure in said one said chamber drops to the level of said conduit means.

Claim 17

The pressure monitor of claim 7 having a safety pressure relief valve connected to said conduit means for relieving pressure in excess of a predetermined value.

Claim 18

A pressure monitor for a lung ventilator having a supply of breathing gas under pressure and an airway conduit for connection to a patient, including in combination: a pressure regulator having an inlet adapted for connection to said supply and having an outlet for gas at a constant preset pressure, a flow control valve having an inlet connected to the outlet from said regulator and an outlet for gas at a constant rate of flow, conduit means connected to said outlet of said flow control valve, airway pressure sensing means comprising a housing and a diaphragm dividing said housing into first and second chambers, said first chamber being adapted for connection to said airway conduit, said second chamber being connected to said conduit means and having an orifice connected to atmosphere, the passage from said second chamber to said orifice being determined by the position of said diaphragm relative to said orifice, whereby the pressure in said conduit means is maintained at the pressure of a said aiRway conduit when said first chamber is connected thereto, said diaphragm isolating said airway conduit from said conduit means, a low-limit detector having a housing and a diaphragm providing a third chamber connected to said conduit means and having a passage, seal means mounted to said diaphragm, and spring means urging said diaphragm to force said seal means to close said passage to said third chamber except when the pneumatic pressure in said third chamber is great enough to overcome the pressure exerted by said spring means, pneumatically-operated timing means having a housing and a diaphragm assembly with two diaphragms providing fourth, fifth, and sixth chambers, a first of said two diaphragms having a smaller effective area than a second of said two diaphragms and lying between said fourth and fifth chambers, while said second diaphragm lies between said fifth and sixth chambers, said fourth chamber having an inlet connected to the outlet from said pressure regulator and having outlet means, said diaphragm assembly carrying a seal and having spring means for urging said seal to close said inlet, orifice means connecting said fourth chamber to said sixth chamber for timed release of gas from said fourth chamber into said sixth chamber to build up pressure in said sixth chamber aiding in urging said seal to close, metering valve means having an inlet connected to said outlet from said regulator and an outlet connected to said passage to said third chamber and to said fifth chamber for supplying a metered flow of gas to said fifth chamber to build up pressure therein that causes said diaphragm assembly to unseat the seal from said inlet to said fourth chamber so that gas flows from said regulator to and through the outlet from said fourth chamber, unless said pressure in said conduit means is sufficient to open said passage to said third chamber, thereby bleeding gas from said metering valve means through said conduit means to said orifice of said airway pressure sensing means, before the pressure in said fifth chamber can build up to the amount needed to unseat the seal in said fourth chamber, a high-limit detector having a housing and a diaphragm providing a seventh chamber in said housing connected to said conduit means and having a nozzle with an inlet outside said seventh chamber and an outlet inside said seventh chamber, seal means mounted to said diaphragm, and spring means urging said diaphragm to force said seal means to close said nozzle outlet except when the pneumatic pressure in said seventh chamber is great enough to overcome the pressure exerted by said spring means, said nozzle inlet then being connected through said seventh chamber and said conduit means to said orifice of said airway pressure sensing means, said high-limit detector also having a small orifice with its inlet connected to said regulator outlet and its outlet connected to the inlet of said nozzle, high-limit pneumatic switch means having a housing and a diaphragm providing eighth and ninth chambers in said housing, said eighth chamber being sealed and connected to the inlet of said nozzle, so that when said nozzle outlet is sealed closed, said eighth chamber reaches the outlet pressure of said regulator and so that the pressure in said eighth chamber drops to the pressure of said conduit means when said nozzle is opened, said ninth chamber having an inlet with a sized restricted passage connected to said outlet of said pressure regulator and an outlet with a sized restricted passage, its said diaphragm closing off said inlet of said ninth chamber when the pressure in said eighth chamber is substantially equal to that of said regulator outlet and opening said inlet of said ninth chamber for flow of gas to the outlet of said ninth chamber when the pressure in said eighth chamber drops to that of said conduit means, and pneumatically-operated warning means connected to the outlet of said ninth chamber and to said outlet means of said fourth chamber for actuation by pnEumatic flow from either of them.

Claim 19

A pressure monitor for a lung ventilator having a supply of breathing gas under pressure and an airway conduit for connection to a patient, including in combination: a pressure regulator having an inlet adapted for connection to said supply and having an outlet for gas at a constant preset pressure, a flow control valve having an inlet connected to the outlet from said regulator and an outlet for gas at a constant rate of flow, conduit means connected to said outlet of said flow control valve, airway pressure sensing means comprising a housing and a diaphragm dividing said housing into first and second chambers, said first chamber being adapted for connection to said airway conduit, said second chamber being connected to said conduit means and having an orifice connected to atmosphere, the passage from said second chamber to said orifice being determined by the position of said diaphragm relative to said orifice, whereby the pressure in said conduit means is maintained at the pressure of a said aiRway conduit when said first chamber is connected thereto, said diaphragm isolating said airway conduit from said conduit means, a low-limit detector having a housing and a diaphragm providing a third chamber connected to said conduit means and having a passage, seal means mounted to said diaphragm, and spring means urging said diaphragm to force said seal means to close said passage to said third chamber except when the pneumatic pressure in said third chamber is great enough to overcome the pressure exerted by said spring means, pneumatically-operated timing means having a housing and a diaphragm assembly with two diaphragms providing fourth, fifth, and sixth chambers, a first of said two diaphragms having a smaller effective area than a second of said two diaphragms and lying between said fourth and fifth chambers, while said second diaphragm lies between said fifth and sixth chambers, said fourth chamber having an inlet connected to the outlet from said pressure regulator and having outlet means, said diaphragm assembly carrying a seal and having spring means for urging said seal to close said inlet, orifice means connecting said fourth chamber to said sixth chamber for timed release of gas from said fourth chamber into said sixth chamber to build up pressure in said sixth chamber aiding in urging said seal to close, metering valve means having an inlet connected to said outlet from said regulator and an outlet connected to said passage to said third chamber and to said fifth chamber for supplying a metered flow of gas to said fifth chamber to build up pressure therein that causes said diaphragm assembly to unseat the seal from said inlet to said fourth chamber so that gas flows from said regulator to and through the outlet from said fourth chamber, unless said pressure in said conduit means is sufficient to open said passage to said third chamber, thereby bleeding gas from said metering valve means through said conduit means to said orifice of said airway pressure sensing means, before the pressure in said fifth chamber can build up to the amount needed to unseat the seal in said fourth chamber, a high-limit detector having a housing and a diaphragm providing a seventh chamber in said housing connected to said conduit means and having a nozzle with an inlet outside said seventh chamber and an outlet inside said seventh chamber, seal means mounted to said diaphragm, and spring means urging said diaphragm to force said seal means to close said nozzle outlet except when the pneumatic pressure in said seventh chamber is great enough to overcome the pressure exerted by said spring means, said nozzle inlet then being connected through said seventh chamber and said conduit means to said orifice of said airway pressure sensing means, said high-limit detector also having a small orifice with its inlet connected to said regulator outlet and its outlet connected to the inlet of said nozzle, high-limit pneumatic switch means having a housing and a diaphragm providing eighth and ninth chambers in said housing, said eighth chamber being sealed and connected to the inlet of said nozzle, so that when said nozzle outlet is sealed closed, said eighth chamber reaches the outlet pressure of said regulator and so that the pressure in said eighth chamber drops to the pressure of said conduit means when said nozzle is opened, said ninth chamber having an inlet with a sized restricted passage connected to said outlet of said pressure regulator and an outlet with a sized restricted passage, its said diaphragm closing off said inlet of said ninth chamber when the pressure in said eighth chamber is substantially equal to that of said regulator outlet and opening said inlet of said ninth chamber for flow of gas to the outlet of said ninth chamber when the pressure in said eighth chamber drops to that of said conduit means, and pneumatically-operated warning means connected to the outlet of said ninth chamber and to said outlet means of said fourth chamber for actuation by pnEumatic flow from either of them.

Claim 20

The pressure monitor of claim 13 wherein said timing means has a second diaphragm assembly with two diaphragms cooperating with the housing thereof to provide three additional chambers, a tenth chamber having a bleed to atmosphere and a nozzle connected to said fifth chamber, the second diaphragm assembly having seal means for closing said nozzle and spring means urging it toward a closed position, an eleventh chamber between said diaphragms connected to said sixth chamber, and a twelfth chamber at atmospheric pressure and containing said spring means, the effective area of the diaphragm between said eleventh and twelfth chambers being greater than that between said tenth and eleventh chambers, a spring support sleeve in said twelfth chamber, and a toggle lever having two positions and in contact with said spring support sleeve, for establishing two different spring compression values acting on said second diaphragm assembly.

Claim 21

The monitor of claim 13 having supply pressure detector means with a diaphragm and a housing providing a tenth chamber with an inlet adapted to be connected to said supply pressure and an outlet, said diaphragm actuating a normally closed poppet valve between said tenth chamber and said outlet therefrom and having spring means urging said diaphragm to open said poppet valve when the pressure in said tenth chamber drops below a predetermined value, said outlet of said tenth chamber being connected to said warning means through a sized restricted passage.

Claim 22

The monitor of claim 13 having a safety pressure relief valve connected to said conduit means for relieving pressure therein in excess of a predetermined value.