PURPOSE: To suppress the power consumption to the minimum requirement by setting an air flow rate for combustion corresponding to a fuel flow rate as to each zone, operating a total air flow rate to each zone, operating a pressure loss received between an air blower and a header, and controlling a revolving speed of the air blower.
CONSTITUTION: Air for combustion from an air blower 1 is preheated by a heat exchanger 3, and is fed to each zone 6aW6c of a continuous billet heating furnace 6 through a header 4. Subsequently, after a fuel throw-in quantity of each zone 6aW6c is determined, an air flow rate for combustion corresponding to the fuel throw-in quantity is set as to each zone by air flow rate setting devices 9aW9c. On the other hand, air pressure required for burners 7aW7c is derived as to each zone by operating devices 17aW17c in which the relation of the air flow rate and necessary air pressure is stored in advance. Subsequently, the maximum air pressure in air pressure in each zone is selected 16, and it is fed to a computer 19 as the air pressure required for the header 4. Subsequently, a pressure loss in case when the operated 19 total air flow rate passes through the exchanger 3 is operated by an operating device 20 in which the relation of the air flow rate and the pressure loss received by the exchanger 3 is stored in advance, and a revolving speed of the air blower 1 is controlled so that the air blower 1 reaches its target exhaust air pressure.
ODOI AKIO
OGAWA HIROMI
WATANABE MAKOTO
