Pressure actuated flow control valve

Abstract

A pressure actuated flow control valve for an infusion catheter permits gravity flow of a liquid through the catheter and into a patient while resisting back flow of blood from the patient and into the catheter. The valve has a hemispherical body with an outstanding circumferential flange and a normally closed, diametric slit. The slit is longer on the convex outer surface than on the concave inner surface. Dome thickness diminishes in the area adjacent the slit, reducing total apical deflection upon collapse of the slit toward the concave surface. An inner orthogonal rib biases the slit closed. Upon application of a predetermined pressure, the slit opens toward the concave surface to permit forward fluid flow. At lower pressures, the slit closes to check fluid flow. Greater reverse pressure is required to collapse the slit toward the concave surface to permit reverse fluid flow.

1 . A pressure actuated flow control valve, comprising: 
 a. a flexible unitary valve body having a central wall with a convex surface and an opposing concave surface where said central wall defines a fluid passageway portal; and    b. a normally closed slit extending through the wall and between the convex and concave surfaces where the side walls of the slit are in near contact with each other in a normally closed relaxed state and said slit extending partially along the diameter of the central wall.    
     
     
         2 . The flow control valve of  claim 1 , where the central wall is dome-shaped having a substantially spherical geometry.  
     
     
         3 . The flow control valve of  claim 1 , where the central wall has a thickness that diminishes approaching the apical area.  
     
     
         4 . The flow control valve of  claim 1 , where the opposing concave surface has a raised elongated rib extending substantially perpendicular to the slit.  
     
     
         5 . The flow control valve of  claim 4 , where the opposing concave surface has a second raised elongated rib extending substantially along the line of the slit.  
     
     
         6 . The flow control valve of  claim 1 , where the lengthwise opposing first and second ends of the slit are angled such that the arcuate length of the slit is shorter as it penetrates the concave surface than it is when it penetrates the convex surface.  
     
     
         7 . The flow control valve of  claim 1 , where the slit lengthwise end to end is not straight.  
     
     
         8 . The flow control valve of  claim 1 , where the central wall is constructed of material having such material characteristics and said central wall and said slit being so dimensionally configured as to resist opening in response to a selected range of backflow pressure applied to said convex surface to resist a backflow of fluid.  
     
     
         9 . The flow control valve of  claim 1 , where the central wall is constructed of material having such material characteristics and said central wall and said slit being so dimensionally configured such that the normally closed slit opens in response to a predetermined selected range of fluid flow pressure applied to said concave surface to allow a flow of fluid where said slit opens toward said convex surface upon application of a predetermined selected range of fluid flow pressure to said concave surface, enabling forward flow through the portal defined by the central wall and said slit closes to check flow through said portal defined by the central wall at a pressure on said concave surface less than said predetermined selected range of fluid flow pressure.  
     
     
         10 . The flow control valve of  claim 1 , wherein: 
 a. said slit opens toward said convex surface upon application of a predetermined first fluid pressure to said concave surface, enabling forward flow through said portal defined by the central wall;    b. said slit closes to check flow through said portal defined by the central wall at a pressure on said concave surface less than said first fluid pressure;    c. said slit opens toward said concave surface upon application of a predetermined second fluid pressure to said convex surface, enabling reverse flow through said portal defined by the central wall;    d. said slit closes to check flow through said portal defined by the central wall at a pressure on said convex surface less than said second fluid pressure; and    e. said second fluid pressure is greater than said first fluid pressure.    
     
     
         11 . The flow control valve of  claim 1 , where the flexible unitary body includes an outwardly extending peripheral flange around a base of the unitary body distal from an apical area of the central wall for engaging the flexible unitary body in a fluid flow passageway.