| 摘要 |
A dispenser includes an improved closure arrangement for sealing the dispenser in such a manner that oxidation of the paste-like product to be dispensed is avoided. The main headpiece is spring biased upwardly toward a first position relative to the container and to the product delivery piston, whereupon the upper end surface of the piston is spaced a given distance from the headpiece, and a cylindrical bearing surface on the headpiece closes the product supply outlets contained in the piston. When the main headpiece is depressed downwardly by the given distance toward an intermediate second position in which the headpiece engages the adjacent piston end surface, the bearing surface on the main headpiece is displaced downwardly to open the piston outlets. Upon further downward displacement of both the headpiece and the delivery piston toward a third position relative to the container, the paste-like product is pumped from the delivery chamber by the delivery piston for discharge via a main product outlet contained in the headpiece.
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