| 摘要 |
A ball valve includes a ball member with a flow passage therethrough, annular recessed surfaces around the ends of the ball member flow passages, resilient seals accommodated in part within the recessed surfaces, and a flow passage member, typically the housing, having annular grooves for accommodating the seals. The flow passage of the ball member, the inside perimeter of the seals, and the flow passage of the flow passage member are of substantially the same dimension. The seals each includes a cleft that opens to its inside perimeter for allowing seal flexing without axial movement when the ball member is rotated closed and the seals are flexed out of their respective recessed surfaces. A two-section mandrel having suitable retractable fingers is used to pre-load the seals when joined together through the ball member passage. The mandrel is sized so that the flow passage member is made in an injection mold around the mandrel, ball member and seals. The retractable fingers allow the mandrel to be separated and the sections removed after the molding step is completed.
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