| 摘要 |
A disposable plastic pump (10) for dispensing liquids is disclosed whic h comprises two basic unitary, preferably all plastic, elements: a chamber forming body (12) having an open outer end and an inner end in fluid communication with a liquid reservoir (26), and a piston (16) formed to slidably fit into the chamber (12). The chamber (12) forms two axially adjacent coaxial chambers, an inner chamber (204) of a larger diameter and an outer chamber (202) of a smaller diameter. The piston (16) comprises a stem (46) on which is located two spaced flexing discs (216, 48) each sized to fit in and serving as a one-way valve In the inner chamber (204) and oute r chamber (202), respectively, permitting fluids to flow outwardly past each flexing disc (216, 48). A sealing disc (50) is located on the stem (46) outwardly of the outermost flexing disc (48). A passageway (52) is provided from an inlet (53) on the piston (16) between the outermost flexing disc (48) and the sealing disc (50) through which the dispensed liquid flows.
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