| 摘要 |
PURPOSE:To prevent decrease in temperature of rolling material by bypass water by closing a nozzle ejecting valve and closing a bypass valve at a last stage of rolling, and by opening the bypass valve and the ejecting valve before starting the descaling of the succeeding feed material. CONSTITUTION:A bypass line 3 of a descaling system is provided with a bypass valve 11 and by closing the valve the flow of the water out of the system is prevented. In this instance, the timing to close the bypass valve 11 is determined by the sheet thickness of the rolling material or temperature, and in a region where the sheet thickness is thin or the temperature decrease is large, it is so arranged that the bypass water will not flow out of the system. During the time after the bypass valve is stopped for a certain period, and until the hydraulic pressure in a piping 8 returns to a prescribed level the descaling work or a high pressure water ejection by opening the nozzle ejecting valve 2 is suspended to prevent water hammer. |
