| 摘要 |
<p>A ball valve having a valve body defining a ball valve chamber and having a longitudinal axis defined by inlet and outlet passages. A ball valve element is rotatably disposed in said valve chamber. The ball valve element has a diametrically disposed fluid passage and is operatively connected to a control lever for rotating the ball valve element between a closed position and an open position. A basket strainer is removably mounted in the ball element passage in the ball valve element. The ball valve is provided with an internal pilot fluid flush passage that connects an inlet port to the ball valve chamber, and a pilot fluid flush discharge port and discharge valve that communicate with the ball valve chamber. A flow control plug valve is movably mounted in the internal pilot fluid flush passage for selective allowing or preventing fluid flow therethrough. When the ball valve element is rotated to a closed position, the flow control plug valve may be moved to an open position to allow upstream fluid to flow through the inlet port and internal pilot fluid flush passage and into the ball valve element chamber and through the basket strainer and out the pilot fluid flush discharge port, to reverse flush out debris captured by the basket strainer.</p> |
