| 摘要 |
A sample preparation apparatus includes a pair of valves. A first valve selectively communicates a sample tube with a vent/aspiration valve, or alternatively communicates a diluent pump with a reaction tube. By moving the first valve, one may selectively relieve a vacuum within a sample tube, aspirate a sample from the tube, or alternatively may drive a diluent and a sample into the reaction tube. The second valve is a vent/aspiration valve which selectively communicates the first valve to two distinct systems. A first system vents a vacuum in the sample tube, and a second system aspirates a sample from the sample tube. The second valve is actuated to initially relieve any vacuum in the sample tube, and is then actuated to connect the aspiration system to the sample tube to begin to withdraw of a sample from the sample tube. At the same time, the diluent pump is filled. The shear valve is then moved to communicate the diluent pump to the reaction tube. The diluent pump is actuated to drive a diluent and a sample slug into the reaction tube, which preferably contains a predispensed reagent. This system simplifies the valving structure over the prior art systems. In addition, a unique rinse system provides a rinse solution to the outer periphery of the needle, while the needle is connected to a source of suction to withdraw the rinse fluid. Finally, a unique structure for holding and properly positioning the reaction tube provides a control signal indicating that a reaction tube is received in the reaction tube structure. If no reaction tube is sensed, a controller deactivates the system such that no fluids are dispensed by the system.
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