| 摘要 |
A flapper valve for a surface controlled, sub-surface safety valve has a seat and a curved flapper. The seat has a seating rim, and the curved flapper has a sealing rim and can pivot relative to the seat. The flapper's sealing rim corresponds in shape to the seating rim. Both rims have lobes disposed outside a circular perimeter. Also, the undulating edges of the rims have corresponding outcroppings and incroppings. When a flow tube moves towards or away from the flapper, the flapper's lobes protect the flapper's sealing rim as the flapper's inside surface engages the moving flow tube. Moreover, the rims can have a groove and a ridge that engage one another when the rims close.
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