| 摘要 |
A packing is provided with a multilayered construction and a cup-like shape. The packing is configured to be carried in a packing holder for reciprocating motion within a pump cylinder. Some of the layers in the packing terminate on the convex face of the cup shape at radially spaced locations therearound. Thus, a peripheral portion of a number of the layers behind the cup lip are exposed to be engaged by the cylinder wall at a continuous contact area therearound. The hardness of the layer located outermost on the convex face is the greatest, and the hardness of each succeeding adjacent layer is lesser than the one immediately preceeding when progressing toward the cup lip along the convex face. Extrusion of the packing between the packing holder and the cylinder wall and subsequent severe localized wear is resisted by the greater hardness layers. A more uniform distribution of pressure across the area of contact between the packing and the cylinder wall is provided by the reduced tendency of the packing to extrude and the decreasing hardness sequence of adjacent layers.
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