PURPOSE: To enable control of combustion proportioning a demand heat load even during a low demand heat load by providing a control device which performs ON-OFF combustion control of a burner during a low demand heat load and effects proportional combustion control of the burner during a high demand heat load.
CONSTITUTION: A control device is connected to a flow rate regulating valve F, and by means of a control output from a controller connected to the control device, the operation of the flow rate regulating valve F is controlled, and not only proportional combustion control but also ON-OFF combustion control is made on combustion of a gun type burner 20. Namely, During a high demand heat load in which a combustion number ranges from No.4 to No.20, proportional combustion control is effected and during a low demand heat load in which a combustion number range from No.2.5 to No.6, ON-OFF combustion control is effected. In the ON-OFF combustion control, the opening of the flow rate regulating valve F is set to No.6, and in following, by performing ON-OFF combustion control of the flow rate regulating valve F at intervals of an arbitrary time, even during a low demand heat load in which the combustion number ranges from No.2.5 to No.4, combustion operation proportioning a demand heat load can be effected like the proportional combustion control.
HAMADA YASUO
NAKAMURA YUZURU
KAWASAKI STEEL CO
NIPPON UPRO KK