Needle device for infusion

Claim 1

A needle device of the type including a liquid passage and an air passage, said needle device comprising: a tubular needle having one end sharpened to facilitate introduction of said tubular needle into a liquid container, said tubular needle forming a portion of the liquid passage along its longitudinal axis; base means having a tube shaped member and a flange member attached perpendicularly at a central portion of said tube shaped member, one end of said tube shaped member being adapted to receive the other end of said tubular needle, said flange member having a through hole formed at its outer periphery, said tube shaped member forming another portion of the liquid passage; cover means having a cylindrical member and a flange member attached perpendicularly at one end of said cylindrical member, said cylindrical member surrounding but being spaced from said one end of said tube shaped member and a portion of said tubular needle which extends beyond said one end of said tube shaped member, the other end of said cylindrical member being tapered to facilitate insertion into a liquid container, said flange member of said cover member being adapted to mate with said flange member of said base means and to form a cavity between said flange members which communicates with said through hole, said flange member of said cover means having an annular projection with an opening, said annular projection being disposed concentrically to said through hole in said flange member of said base means when said flange members are mated to each other; the air passage being formed by the space between said cylindrical member and said tubular needle, the space between said cylindrical member and said tube shaped member, the cavity formed between the flange members of said cover means and said base means, the at least one opening in said annular projection and the through hole in said flange member of said base means; and valve means for opening the air passage to facilitate air flow along the air passage in a forward direction and for closing the air passage to prevent liquid from flowing along the air passage in a reverse direction, said valve means including a disc shaped member having top and bottom sides and being disposed within said annular projection opposite to said through hole, said disc shaped member being moved to a valve open position, away from the through hole, by air pressure incident on the bottom side of the disc shaped member through said through hole and being moved to a closed valve position, against the through hole, by liquid pressure incident on the top side of the disc shaped member from a liquid container.