| 摘要 |
A stopper of an evacuated-tube blood sampling system has a sealing portion fitting in or on the tube and an enlarged external hollow head having a chamber closed by a thin sealing diaphragm which obturates the evacuated tube or vial. Flexible lips on an outer end wall of the head define a narrow central opening receiving and lightly gripping a flexible needle sleeve to pre-assemble the evacuated tube with the needle and its holder without a need to partially perforate the membrane. As the needle pierces the diaphragm, the needle sleeve is free to buckle within the chamber, thus reducting or cancelling the biasing effect exerted by the buckled sleeve. The sealing portion of the stopper can have annular and axial grooves providing a ventilating system. |
