| 摘要 |
Deposits of magnetite on tubes 82 in a heat exchanger, e.g. a steam generator, are detected by measuring the magnetic reluctance within the tubes. A probe 84 for measuring the reluctance includes a permanent magnet (or a magnetic core and an excitation coil would on the core 88, 92) and a magnetic flux detector such as a Hall generator mounted for example on one of the non-magnetic rings 90. Changes in flux density as the probe is pushed through the tubes are detected by the Hall generator, thus indicating the presence of magnetite deposits. The probe includes a non-magnetic tube 86 for pushing it through the heat exchanger tubes. <IMAGE> |
