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Fluid injector

  • US 5,012,845 A
  • Filed: 08/18/1988
  • Issued: 05/07/1991
  • Est. Priority Date: 08/18/1988
  • Status: Expired due to Term
First Claim
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1. In apparatus useful for the pick up of a fluid specimen from a fluid specimen-containing septum sealed vial carried by a magazine, and injection of preselected quantities of the fluid specimen into an analytical instrument, the combination comprisinga syringe assembly which includesa barrel,a plunger rod reciprocably mounted in one end of the barrel,a pair of concentric hollow needles of different diameters, an outer larger diameter needle containing a side wall opening communicating with the axial opening therethrough, mounted in the end of the barrel opposite the plunger to form an annulus between the external wall surface of said inside smaller diameter needle and the inside wall surface of said larger diameter needle,means for reciprocation of the plunger rod within the barrel of the syringe,means for the reciprocal movement of the syringe barrel,a tubular block valve the tubular opening through which said concentric pair of needles can be projected into a vial carried by said magazine and positioned in-line therewith, said valve further including a pair of lateral channels communicated with said tubular opening, the first of said lateral channels fluidly communicating with a pressurized gas, the second of said lateral channels adapted to be connected to said analytical instrument,whereby, when the dispensing end of the pair of needles is projected through the septum into a vial and an end of the smaller diameter needle immersed in a fluid specimen, gas is passed via the side wall opening of the large diameter needle and the first lateral opening of said block valve via the needle annulus to pressurize the fluid contents of the vial and drive fluid specimen into the axial opening of the small diameter needle, and on retraction of the plunger rod into the syringe barrel, and on the closure of said first lateral block valve opening and opening of the second lateral block valve opening, the fluid specimen can be displaced from the syringe barrel and expressed via said second lateral block valve opening to the analytical instrument.

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