High pressure syringe

Claim 1

In apparatus comprising a syringe useful for receiving and accurately measuring small quantities of a fluid specimen from a pressurized source, for dispensing, the syringe having the usual hollow barrel formed by an enclosing wall providing a bore, a reciprocable plunger fitted in said bore in sliding, sealing relationship therewith, said barrel having a hollow needle with dispensing end located on the opposite end of said barrel, the hollow opening of which is in communication with the bore of said barrel, the improvement which comprises, as a part of the combination, a valved needle assembly which includes a tubular adapter within the axial opening of which the hollow needle is rigidly mounted, said needle containing a wire of external diameter less than the diameter of the internal opening through the needle, the needle being sealed at its rearward end and being provided with a side opening which connects with the annulus which forms an open communication with the dispensing end of the needle, the tubular adapter being slidably mounted within a slip fitting which can be operatively affixed upon the wall which forms the forward end of the barrel, the tubular adapter including a resilient tubular seal mounted therein within the axial opening of which the side opening of the needle can be snugly contained and communication between the openings of the needle and barrel closed or extended through said axial opening thereof and into the bore of the barrel to open communication between the openings of the needle and barrel by movement of the tubular adapter within the slip fitting, whereby, when the communication between the openings of the needle and barrel are closed by containment of the side needle opening inside the resilient tubular seal, the dispensing end of the needle can be inserted into a pressurized source of a fluid specimen, the openings between the needle and barrel can then be opened by projection of the side needle opening through the resilient tubular seal and into the bore of the barrel, such that on retraction of the plunger, a fluid specimen can be withdrawn from the pressurized source by passage thereof from the dispensing end of the needle through the annulus formed between the wire and inside wall of the needle, and via the side opening of the needle into the barrel, and when the communication between the needle opening and barrel is closed by movement of the side opening of the needle into the resilient tubular member, an accurately measured portion of the fluid specimen can be trapped within the barrel for subsequent injection when the dispensing end of the needle is inserted into a media, the communication between the barrel and needle openings reopened, and the plunger pushed forward.