| 摘要 |
A cementing tool includes a tubular housing having a cementing port disposed through a wall thereof. An upper adapter has its lower end connected to the tubular housing, and has a second end adapted for connection to a string of pipe. A sliding sleeve valve assembly is located within the tubular housing and is slidable relative thereto between an open position wherein said cementing port is open, and a closed position wherein said cementing port is closed. A protective sleeve has its lower end connected to the sliding valve sleeve assembly and has its upper end slidingly received within an inner cylindrical surface of the lower end of the upper adapter. The protective sleeve is always received within said cylindrical surface of the upper adapter so that it always covers a gap between the lower end of the upper adapter and the sliding valve sleeve assembly, thereby preventing any device which is passed through an inner bore of the cementing tool from entering said gap and hanging up thereon. |
