| 摘要 |
A differential fill valve assembly for application in float collars or shoes in a well casing can provide a mechanism for releasing a flapper valve by advancing and activating sleeve of the valve assembly. The valve assembly includes a backpressure flapper valve and an activating sleeve slidably disposed within a housing. The activating sleeve initially maintains the flapper valve in an open position. The activating sleeve provides at least one ramp on an inner surface thereof. Fluid flow through the activating sleeve generates a pressure differential, across the activating sleeve that produces a net force on the activating sleeve to drive the activating sleeve downward, releasing the backpressure flapper valve. |
