| 摘要 |
A downhole tool has a housing, mandrel, and ball seat. The housing defines a first bore, and the mandrel defines a second bore. The mandrel is disposed in the first bore of the housing and defines an annular space with the housing. The ball seat is rotatably disposed in the second bore of the mandrel and defines an interior passage with a seat profile. First and second pistons are disposed in the annular space on opposing sides of the ball seat. These first and second pistons are movable along an axis of the tool in the annular space in opposing directions and are adapted to rotate the ball seat. Additionally, first and second biasing members are disposed in the annular space and bias the first and second pistons toward one another to reset the ball seat in the absence of pressure. |
