Pump and exhalation valve control for respirator apparatus

Abstract

Double acting respirator pump apparatus including a pump member reciprocable with respect to two pump chambers to deliver air to a patient via a respirator exhalation system, which also facilitates exhalation of the patient. The exhalation system has a pump unit that is operatively connected to an exhalation valve member and configured for selectively generating an air pressure sufficient for pressurizing one side of the valve member for closing the same when said exhalation system is operating in inhalation mode, and may be operated for opening to allow the patient to exhale therethrough.

1 . Double acting respirator pump apparatus comprising a housing defining two pump chambers and a pump member reciprocable with respect to said pump chambers and configured to provide an inlet stroke and an outlet stroke with respect to each said chamber in each reciprocation cycle of said pump member, wherein said inlet stroke and said outlet stroke for each pump chamber defines for the respective pump chamber a displacement volume that is displaced in the respective pump chamber by reciprocation of the pump member in one reciprocation cycle between the respective inlet stroke and the respective outlet stroke, and wherein a volume of at least one said pump chamber at the end of the respective said output stroke thereof is a first proportion of the respective said displacement volume, wherein said first proportion is not less than about 50%, and wherein said pump member comprises a piston reciprocably mounted with respect to said pump chambers via a rolling convolution diaphragm peripherally joined to the piston and anchored with respect to each said pump chamber, and wherein said diaphragm is configured for avoiding being collapsed during the output stroke of each said pump chamber. 
     
     
         2 . Pump apparatus according to  claim 1 , wherein said diaphragm is configured to have a portion thereof that bulges in a direction towards one said pump chamber and away from the other said pump chamber regardless of a position of said piston within said reciprocation cycle during operation of said pump. 
     
     
         3 . Pump apparatus according to  claim 1 , comprising a pump inlet port and a pump outlet port, wherein said pump inlet port is in fluid communication with an inlet valve of at least one said pump chamber via at least one inlet chamber having a first volume, and wherein said pump outlet port is in fluid communication with an outlet valve of at least one said pump chamber via at least one outlet chamber having a second volume, and wherein each one of said first volume and said second volume is at least a second proportion of said displacement volume of said respective pump chamber, wherein said second proportion is not less than about 50%. 
     
     
         4 . Pump apparatus according to  claim 3 , wherein each said pump chamber comprises a respective said inlet chamber and a respective said outlet chamber, and wherein said outlet chamber of one said chamber is in fluid communication with said outlet chamber of the other said pump chamber, and wherein said inlet chamber of one said chamber is in fluid communication with said inlet chamber of the other said pump chamber. 
     
     
         5 . Pump apparatus according to  claim 1 , wherein said diaphragm has a convolution diameter that is between about 5% and about 15% of a diameter of said piston as projected in said first direction. 
     
     
         6 . Pump apparatus according to  claim 5 , wherein said diaphragm is made from a flexible material, having a hardness of between about 50 Shore A and about 70 Shore A. 
     
     
         7 . Pump apparatus according to  claim 1 , wherein said piston has an axial translation in a reciprocation direction of said piston between a top dead center position corresponding to an end of an output stroke of one said pump chamber, and a bottom dead center position corresponding to an end of an output stroke of the other said pump chamber, wherein said axial translation is between about 10% and about 20% of a diameter of said piston. 
     
     
         8 . Pump apparatus according to  claim 1 , wherein said piston is driven by a motor by means of a crank and piston shaft arrangement. 
     
     
         9 . Pump apparatus according to  claim 8 , wherein said crank and piston shaft arrangement are accommodated in a shaft housing in fluid communication with one said pump chamber, and wherein said motor is accommodated in a motor housing and operatively connected to said crank in a manner providing for sealing of said respective pump chamber within respect to said motor housing. 
     
     
         10 . Pump apparatus according to  claim 9 , wherein said motor comprises a driveshaft operatively connected to said crank, and wherein said driveshaft is mounted with respect to said shaft housing via a bearing arrangement, and wherein said bearing arrangement comprises an integral seal for sealing said respective pump chamber with respect to said motor housing. 
     
     
         11 . Pump apparatus according to  claim 4 , wherein said housing comprises a first end part including said inlet chamber and said outlet chamber of one said pump chamber, a second end part including said inlet chamber and said outlet chamber of the other said pump chamber, a first cylinder part and a second cylinder part, wherein said diaphragm is anchored between said first cylinder part and said second cylinder part to define one said pump chamber in each one of said first cylinder part and said second cylinder part, and wherein said first end part and said second end part are respectively mountable to said first cylinder part and said second cylinder part. 
     
     
         12 . Pump apparatus according to  claim 4 , comprising a pump inlet port and a pump outlet port, wherein said pump inlet port is in fluid communication with said inlet chamber of each said pump chamber, and wherein said pump outlet port is in fluid communication with said outlet chamber of each said pump chamber. 
     
     
         13 . Double acting respirator pump apparatus comprising a housing defining two pump chambers and a pump member reciprocable with respect to said pump chambers and configured to provide an inlet stroke and an outlet stroke with respect to each said chamber in each reciprocation cycle of said pump member, wherein said inlet stroke and said outlet stroke for each pump chamber defines for the respective pump chamber a displacement volume that is displaced in the respective pump chamber by reciprocation of the pump member in one reciprocation cycle between the respective inlet stroke and the respective outlet stroke, and wherein a volume of at least one said pump chamber at the end of the respective said output stroke thereof is a first proportion of the respective said displacement volume, wherein said first proportion is not less than about 50%, and wherein said pump member comprises a piston reciprocably mounted with respect to said pump chambers, wherein said piston has a axial translation in a reciprocation direction of said piston between a top dead center position corresponding to an end of an output stroke of one said pump chamber, and a bottom dead center position corresponding to an end of an output stroke of the other said pump chamber, wherein said axial translation is between about 10% and about 20% of a diameter of said piston as projected in a direction substantially orthogonal to said reciprocation direction. 
     
     
         14 . Respirator exhalation system for facilitating exhalation of a patient connected to a respiratory apparatus, comprising an exhalation valve and a pump unit that is operatively connected to said exhalation valve and configured for selectively generating an air pressure sufficient for pressurizing one side of said valve member for closing the same when said exhalation system is operating in inhalation mode. 
     
     
         15 . Respirator system according to  claim 14 , wherein said pump unit comprises a pump control member and a housing having a seat, wherein a pumping chamber is defined between said pump control member and said seat, wherein in operation of said pump unit said pumping chamber comprises a confined volume of compressible air, and wherein said pumping chamber is in fluid communication with a control chamber comprising said valve member, and wherein said pump unit is configured for selectively bringing said pump control member into proximity with said housing seat to compress said volume of compressible air and thereby to generate a pump pressure for pressurizing said side of said valve member. 
     
     
         16 . Respirator system according to  claim 15 , wherein said pump control member comprises an armature, and said housing comprises an electric coil, and wherein energizing said coil magnetically attracts said armature to bring said pump control member into proximity with said housing seat, thereby compressing air enclosed in said pumping chamber and generating said pump pressure. 
     
     
         17 . Respirator system according to  claim 16 , wherein said pump unit is configured for modulating said pump pressure by selectively variably energizing said coil. 
     
     
         18 . Respirator system according to  claim 16 , wherein said armature is connected to said housing seat via a flexible resilient diaphragm, wherein said diaphragm is  15  configured for providing substantially hysteresis-free operation of said pump unit. 
     
     
         19 . Respirator system according to  claim 18 , wherein said diaphragm extends between said armature and said housing seat, preventing contact therebetween when said coil is fully energized and providing for rapid separation therebetween when said coil is not energized. 
     
     
         20 . Respirator system according to  claim 18 , wherein said diaphragm is biased to space said armature away from said housing seat when said coil is not energized. 
     
     
         21 . Respirator system according to  claim 14 , further comprising a two-way control valve in fluid communication with said pumping chamber and said side of said valve member, and configured for selectively venting said side of said valve member. 
     
     
         22 . Respiratory apparatus comprising the respiratory pump as defined in  claim 1  operatively connected to a respirator exhalation system for facilitating exhalation of a patient connected to said respiratory apparatus. 
     
     
         23 . Respiratory apparatus comprising a respiratory pump apparatus for delivering pressurized gas to a patient connected to said respiratory apparatus, the respiratory pump apparatus being operatively connected to a respirator exhalation system as defined in  claim 14 .