| 摘要 |
PURPOSE:To early detect the blockage of a carrier tube by detecting the lowering of the carrier tube for carrying a gas to be carried. CONSTITUTION:The gas to be carried is kept at a temperature which is higher by 10-100 deg.C than the ambient temperature of a carrier tube 3 by means of a heater. On the surface of each carrier tube 3 is provided a temperature meter 14. The detected value with respect to an average value of a deviation between the measured value of the temperature meter 14 and the measured value of a temperature meter on the surface of the carrier tube connected to the same distributor or the detected value of a difference between the measured value of the temperature meter 14 provided in the carrier tube 3 and a deviation between the measured value of a temperature meter 8 provided on the surface of a carrier master tube 1, and the average value of the carrier tube connected to the same distributor, are out of a preset scope, it is looked upon as the blockage of the carrier tube and a blocking signal is emitted. A stop valve 15 is closed by the blocking signal and a switching valve 17 is opened, and a high-pressure gas for purging is caused to flow to the upstream side and downstream side of the stop valve 15 to push out the pulverized substance and to restore the tube to the original condition.
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