| 摘要 |
<p>A chamber has an open bottom that is adapted to rest on a sheet of filter paper, and has an aperture for the introduction of solids together with liquid for extracting soluble material therefrom. A piston is reciprocated between a position above such aperture and a position below the aperture where the piston has a sealing engagement with the interior of the chamber. Hold-down apparatus for the chamber is synchronized with the mechanism for reciprocating the piston and operates during the downward stroke of the piston to press the chamber downward against the filter paper, and also operates to free the chamber for upward movement by friction between the chamber and the piston during upward movement of the piston. A stop limits the upward movement of the chamber.</p> |
