| 摘要 |
A pen-size syringe has a needle secured to a hub at one end and a valve located near the hub and slidable transversely of the syringe axis by the forefinger of the user, from a closed condition, to a sampling condition, to a needle venting condition. A plunger in the syringe is axially slidable by manually pulling a portion projecting out the other end of the syringe to establish a vacuum in the syringe when the valve is closed. A latch is provided to keep the plunger in the vacuum establishing position. With the vacuum established, and the needle point situated at the sampling site, the valve is operable by the index finger to open the vacuum chamber to the needle for taking the specimen, following which the finger pushes the valve to the further position venting to needle to atmosphere, for removal of the needle, and any contained sample.
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