| 摘要 |
1331116 Controlling reheating furnaces GENERAL ELECTRIC CO 26 Nov 1970 [15 Dec 1969] 56362/70 Heading F4B The heat input to at least one zone of a slab reheating furnace is controlled by calculating the temperature of each slab in the zone from its dimensions, thermal properties, location and previous history, and the gas temperature in the zone, comparing this with a desired slab temperature at that location to produce a temperature deviation, obtaining a performance index as a function of all the deviations in the zone and adjusting the heat input as a function of the performance index. The temperature deviation of each slab may be weighted in accordance with the location of the slab so that the deviation of a slab near the zone exit has more effect than that of a slab near the zone entry in determining the performance index. The arrangement is such that allowances are made for hold ups, and the additional heat requirement at decalescenoe, and the required temperature change is held between set values. The temperature of a slab is not allowed to rise above that at which it starts to melt. Pyrometers measure the actual surface temperature of the slabs, and a factor representing a thermal property of the slab in the equation used to calculate the slab temperature from the gas temperature at each end of the zone is modified to compensate for errors in the calculated temperature. |
