| 摘要 |
A seat assembly extending about an inlet passage of a valve and engaging a valve member is disclosed. The seat assembly includes an annular seat carrier having an annular groove formed therein, and a seat positioned in and extending from the annular groove of the seat carrier. The seat has an inner side, an outer side, and a plurality of spaced apart, concentric seal rings extending from the inner side of the seat to the outer side thereof. The seal ring nearest the inner side of the seat is engageable with the valve member to provide an innermost seal when the seat assembly is acted upon by a pressure within a pressure range and the seal ring nearest the inner side of the seat is deflectable in a radially outward direction and out of sealing engagement with the valve member when the pressure exceeds the pressure range to cause the adjacent seal ring to provide the innermost seal.
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