Patent ID: 7331942

Claim:
An I.V. flush syringe assembly comprising: a barrel including a cylindrical side wall having an inside surface defining a chamber for retaining fluid, an open proximal end and a distal end including a distal wall with an elongate tip extending distally therefrom having a passageway therethrough in fluid communication with said chamber; a plunger including an elongate body portion having a proximal end, a distal end and a stopper slidably positioned in fluid-tight engagement with said inside surface of said barrel for drawing fluid into and driving fluid out of said chamber by movement of said stopper relative to said barrel, said elongate body portion extending outwardly from said open proximal end of said barrel; and anti-reflux means comprising said stopper having a conically shaped distal surface and said inside surface of said barrel at said distal wall being conically shaped wherein a total included angle of said inside surface of said barrel at said distal wall is greater than a total included angle of said stopper distal surface by at least 6°, wherein upon delivery of fluid from said chamber, said stopper contacts the distal end of the barrel and seals said passageway so that stopper deflection is controlled.