| 摘要 |
A dispensing means ( 10 ) for delivering a dose of a first liquid into a second liquid is provided, the dispensing means comprising an enclosure ( 12 ) for the first liquid, and valve means ( 16 ), the dispensing means being operable such that raising a level ( 114 ) of a second liquid relative to the dispensing means so as to subject the dispensing means to hydrostatic pressure causes a dose of the first liquid to be displaced from the enclosure ( 12 ) to establish a column ( 118 ) of the first liquid that acts on the valve means, and subsequent lowering of the level ( 114 ) of the second liquid relative to the dispensing means so as to reduce the hydrostatic pressure acting on the valve means ( 16 ) causes the valve means to deliver the dose. Also provided is a valve means ( 16 ) adapted for attachment to an inlet tube and comprising a valve body ( 62 ) and a flexible membrane ( 72 ), which, when attached to an inlet tube ( 22 ) containing a column of a first liquid and immersed in a second liquid, the hydrostatic pressure causes the flexible membrane ( 72 ) to seal the valve body ( 62 ) so as to prevent a flow of the first liquid, and when a level of the second liquid is lowered, the flexible membrane ( 72 ) unseals the valve body ( 62 ) so as to allow a flow of the first liquid through the valve body ( 62 ).
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