| 摘要 |
The invention is directed to a hand-operated vacuum pump and more specifically, a hand-held and hand-operated vacuum pump for obstetrical use incorporating an improved vacuum regulation system. The hand-held and hand-operated vacuum pump comprises a cylinder, having a piston located therewithin. The piston is movable between extended and retracted positions by a hand-operated lever. There is a first passage extending into the cylinder from an external space to be evacuated. The space is defined by the scalp of a baby and a vacuum cranial bell fitted thereon. A second passage connects this intermediate chamber with the cylinder through a first valve, preferably a one-way valve located in the cylinder head. A third passage connects the intermediate chamber to a second valve which automatically controls the maximum vacuum in the external space. A fourth passage from the intermediate chamber is a vacuum adjustment valve.
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