| 摘要 |
A resetable tool for circulating fluid in a borehole comprises a tubular body 20 with radial outlet ports 24 in which is located a sleeve 62 radial outlets ports 32. When the tool is run into a borehole the sleeve is in a first position where the radial ports 24, 32 are misaligned. A ball 68 is dropped into the tool and lands on a seat 38 on the sleeve 62 forcing the sleeve to down to a second, intermediate position where fluid flow is restricted by the ball 68. On increasing pressure behind the ball 68, the ball passes through the sleeve 62 releasing pressure and allowing the sleeve 62 to move back up to a third position where the outlet ports 24,32 are aligned. A second, identical ball can be dropped into the tool moving the sleeve 62 to its second position; on increasing the pressure again the second ball can pass through the sleeve releasing the pressure and allowing the sleeve to return and reset to its first position. An index tool (figure 2) and biasing spring 52 can control the position of the sleeve 62. |
