Breathable gas inlet control device for respiratory treatment apparatus

Abstract

A breathable gas inlet control device permits flow regulation at the inlet of a flow generator for a respiratory treatment apparatus such as a ventilator or continuous positive airway pressure device. The device may implement a variable inlet aperture size based on flow conditions. In one embodiment, an inlet flow seal opens or closes the inlet to a blower in accordance with changes in pressure within a seal activation chamber near the seal. The seal may be formed by a flexible membrane. A controller selectively changes the pressure of the seal activation chamber by controlling a set of one or more flow control valves to selectively stop forward flow, prevent back flow or lock open the seal to permit either back flow or forward flow. The controller may set the flow control valves as a function of detected respiratory conditions based on data from pressure and/or flow sensors.

1 . A respiratory treatment apparatus configured to provide a flow of breathable gas to a patient in successive respiratory cycles, each cycle including an inspiration phase and an expiration phase, comprising:
 a gas inlet having a variable aperture that is adjustable between a range of positions from a closed position to a fully open;   a gas outlet; and   a flow generator adapted to provide a supply of pressurized breathable gas from the gas inlet and to the gas outlet; and   a controller to control a level of pressure generated by the flow generator,   wherein the controller is configured with flow-by control wherein a seal of the variable aperture is controlled during expiration to allow a level of flow through the gas inlet to compensate for leak at a patient interface.   
     
     
         2 . The apparatus of  claim 1 , wherein the controller, during the expiration phase, is configured to power the flow generator for generating a low level of flow based on a flow set point of a flow control loop. 
     
     
         3 . A respiratory treatment apparatus configured to provide a flow of breathable gas to a patient in successive respiratory cycles, each cycle including an inspiration phase and an expiration phase, comprising:
 a gas inlet having a variable aperture that is adjustable between a range of positions from a closed position to a fully open;   a gas outlet; and   a flow generator adapted to provide a supply of pressurized breathable gas from the gas inlet and to the gas outlet; and   a controller to control a level of pressure generated by the flow generator,
 wherein the controller is configured to control the variable aperture to prevent a back flow into the respiratory treatment apparatus from a patient interface upon detection of an inspiratory pause or plateau. 
   
     
     
         4 . The respiratory treatment apparatus of  claim 3 , wherein the controller controls the variable aperture by setting a flow control valve of a plurality of flow control valves. 
     
     
         5 . The respiratory treatment apparatus of  claim 4 , wherein the setting of the flow control valve closes a flow back conduit coupled between an outlet of the flow generator and a port of the flow control valve. 
     
     
         6 . The respiratory treatment apparatus of  claim 3 , wherein the controller controls the flow generator to set a minimum speed upon detection of the inspiratory pause or plateau. 
     
     
         7 . A respiratory treatment apparatus configured to provide a flow of breathable gas to a patient in successive respiratory cycles, each cycle including an inspiration phase and an expiration phase, comprising:
 a gas inlet having a variable aperture that is adjustable between a range of positions from a closed position to a fully open;   a gas outlet; and   a flow generator adapted to provide a supply of pressurized breathable gas from the gas inlet and to the gas outlet; and   a controller to control a level of pressure generated by the flow generator,   wherein the controller is configured to detect blocking of an expiratory valve associated with venting of a patient interface thereby preventing patient exhalation during expiration and, upon detection of the blocking, to control the variable aperture to permit flow back into the respiratory treatment apparatus from the patient interface.   
     
     
         8 . The respiratory treatment apparatus of  claim 7 , wherein the controller controls the variable aperture by setting a set of flow control valves to equalize pressure of a seal activation chamber and a portion of an inlet chamber. 
     
     
         9 . The respiratory treatment apparatus of  claim 8 , wherein the setting of the flow control valve permits patient expiratory flow to open the variable aperture. 
     
     
         10 . The respiratory treatment apparatus of  claim 7 , wherein the controller controls the flow generator to set a minimum speed upon detection of the blocking.