Industrial furnace which can be used for example for treating semi-finished and siderurgical products, metal and inorganic materials, comprising: - a hot chamber in which a combustion takes place and the hot gases generated by the combustion come in direct contact with the materials to be treated (p) in the furnace itself; - a combustion stabilising system in turn comprising: - an injection system in turn comprising at least a mixer arranged to mix a fuel and a diluent before injecting them into the hot chamber, wherein the diluent has the effect of reducing the amount of nitrogen oxides in the combustion products; - a control system arranged to act on the injection system so as to eliminate or, in any case, reduce the formation of flames or of other hot spots during the combustion in the hot chamber, where the hot spots indicate that the combustion is taking place in presence of flame, wherein the control system comprises at least a vibration detector arranged to detect optical, electromagnetical, acoustic or mechanical vibrations in the hot chamber and is arranged to control the injection system according to the detections of the vibration detector so as to eliminate or, in any case, reduce the formation of flames during the combustion in the hot chamber, so as to keep the combustion in the hot chamber as much as possible in flameless conditions, and wherein the control system is programmed or, in any case, configured to perform the following operations: - associating a target frequency spectrum with combustion conditions in the furnace to be reached, wherein said combustion conditions to be reached are combustion conditions with no flame; - comparing the target frequency spectrum with the frequency spectrum of the signal or of the signals emitted by the at least one vibration detector; - acting on the at least one mixer and/or on the at least one injector so as to vary the flow rate of the fuel and/or diluent fed into the hot chamber so as to make the frequency spectrum of the signal or of the signals emitted by the at least one vibration detector more similar to the target frequency spectrum. - a hot chamber in which a combustion takes place and the hot gases generated by the combustion come in direct contact with the materials to be treated (p) in the furnace itself; - a combustion stabilising system in turn comprising: - an injection system in turn comprising at least a mixer arranged to mix a fuel and a diluent before injecting them into the hot chamber, wherein the diluent has the effect of reducing the amount of nitrogen oxides in the combustion products; - a control system arranged to act on the injection system so as to eliminate or, in any case, reduce the formation of flames or of other hot spots during the combustion in the hot chamber, where the hot spots indicate that the combustion is taking place in presence of flame, - associating a target frequency spectrum with combustion conditions in the furnace to be reached, wherein said combustion conditions to be reached are combustion conditions with no flame; - comparing the target frequency spectrum with the frequency spectrum of the signal or of the signals emitted by the at least one vibration detector; - acting on the at least one mixer and/or on the at least one injector so as to vary the flow rate of the fuel and/or diluent fed into the hot chamber so as to make the frequency spectrum of the signal or of the signals emitted by the at least one vibration detector more similar to the target frequency spectrum.