| 摘要 |
Valve seat rings are provided having sediment guard recesses formed in the back face portions thereof, which recesses are in the form of annular grooves having restricted annular openings and defining an internal stop shoulder. A sediment guard is movably positioned within the receptacle and includes an annular sediment blocking portion that protrudes through the restricted groove for sediment blocking engagement with a radial surface defining a portion of the seat recess. The sediment guard also defines a stop portion that is engageable with the stop shoulder to prevent separation of the sediment guard from its receptacle. The sediment guard is urged toward the radial surface of the seat recess by compression springs located within the receptacle.
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