| 摘要 |
<p>In order to detect abnormal movement of a body, such as a boiler unit (19,20,21) in a nuclear reactor, a fluid is fed into a passage (24), and movement of the body causes variation in the resistance of the passage to flow of the fluid. This variation is detected by measuring a change in flow rate or a change in fluid pressure. The detector preferably comprises a sleeve valve (22) comprising a pipe section (24) which is attached to a central one of three adjacent boiler units and a sleeve (30) which is normally positioned over a port (28,29) in the pipe section and which is coupled to both of the outer boiler units, so that abnormal movement of any of the three units causes opening of the port. The coupling comprises an arrangement of levers and linkages (31-41) which compensates for normal movements of the boiler units caused by temperature rise.</p> |
