Venting, self-stopping, aspirating syringe
First Claim
1. A syringe assembly comprising:
- a tubular body open at one end and being adapted to receive a hypodermic needle at the other end thereof;
a plunger, one end of which is adapted for insertion into said tubular body through said open end, said plunger having a longitudinal passageway for air flow therethrough;
means for forming a fluid-tight seal between the outside surface of said plunger and the inside surface of said tubular body;
an air permeable filter membrane extending across said passageway adjacent said one end of said plunger; and
valve means extending across said passageway between said membrane and said open end of said tubular body for selectively permitting the passage of air through said passageway.
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Accused Products
Abstract
A syringe comprises a main tubular body, the body being open at one end and receiving a hypodermic needle at the other end, and a plunger, one end of the plunger extending into the body, through the open end thereof, the plunger having a longitudinal passageway therein permitting air flow therethrough. A fluid-tight seal is formed between the outside surface of the plunger and the inside surface of the syringe body. An air permeable filter membrane extends across the first end of the plunger, in the passageway, whereby the body can fill with blood, causing the air in the body to pass through the membrane to the open end of the body. Upon contact with the blood, the membrane swells and seals, automatically stopping the flow of blood. A one way valve extending across the passageway allows the syringe to be used to aspirate in the absence of natural blood pressure.
105 Citations
12 Claims
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1. A syringe assembly comprising:
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a tubular body open at one end and being adapted to receive a hypodermic needle at the other end thereof; a plunger, one end of which is adapted for insertion into said tubular body through said open end, said plunger having a longitudinal passageway for air flow therethrough; means for forming a fluid-tight seal between the outside surface of said plunger and the inside surface of said tubular body; an air permeable filter membrane extending across said passageway adjacent said one end of said plunger; and valve means extending across said passageway between said membrane and said open end of said tubular body for selectively permitting the passage of air through said passageway. - View Dependent Claims (2, 3, 4, 5)
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6. A plunger for use with a conventional syringe comprising:
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an elongated body having a longitudinal passageway therein for permitting air flow therethrough; an air permeable filter membrane extending across said passageway adjacent one end of said body; and valve means extending across said passageway between said membrane and the other end of said body for selectively permitting the passage of air through said passageway. - View Dependent Claims (7, 8, 9, 10, 11, 12)
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Specification