| 摘要 |
A pressure balanced ball valve assembly includes a ball valve mounted within a unitary cage which has limited axial movement within a stationary tubular body. Annular pistons are slidably mounted within the cage for movement toward and away from the outer surface of the ball valve. Pressure transfer balance conduits extend from locations on one side of the ball valve to annular chambers at opposite ends of the cage. The effective area on the ball valve subjected to upstream pressure is balanced by the effective area of an annular chamber in which the same unit pressure acts on the downstream end of the cage. The balance conduits each lead from one side of the ball valve to a remote chamber at the other end of the cage.
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