Abstract: A repairing method using a lance for repairing an oven wall surface of a coke oven comprises the steps of arranging a distance sensor at a top end of the lance, quantitatively measuring a depth of a worn or a damaged area by the distance sensor, and blowing a repairing material from a repairing nozzle to the worn area in accordance with a measurement result to thereby repair the worn area. The lance used in this repairing method has a multistage structure having a polygonal cross section and is extendable. With this structure, the oven wall surface can be scanned in a linear fashion or along a plane. If the top end of the lance is movable in accordance with a basic motion pattern and/or a travelling pattern, it is possible to readily repair a repair range having a complicated shape.

Abstract: An apparatus for controlling the injection quantity of pulverized coal by measuring the flow rate of the pulverized coal in a conveying pipe, through which the pulverized coal is injected into tuyeres of a blast furnace, in order to regulate the opening of a valve installed between a feed tank and the conveying pipe based on the measured flow rate, and also by regulating the internal pressure of the feed tank so as to maintain the difference in the internal pressure between the feed tank and the conveying pipe within a predetermined range. The thus configured apparatus provides rapid-response and high-accuracy in control, wide-range controllability, and allows to control the injection quantity of the pulverized coal even when supplying the pulverized coal to the feed tank.