Combustion device

Abstract

The present invention provides a combustion device. In ON-OFF combustion control processing for intermittently performing the combustion operation of burners ( 4 ), a control unit ( 30 ) of a combustion device (water heater) ( 1 ), which includes the burners ( 4 ), a fuel supply unit ( 5 ), and a combustion fan ( 10 ), controls the fuel supply unit ( 5 ) and the combustion fan ( 10 ) so as to change the amount of a fuel to be supplied to the burners ( 4 ) and the number of rotations of the combustion fan ( 10 ) according to a required amount of heat for the temperature control of a target fluid (water for hot water supply) when the burners ( 4 ) are ignited to restart a combustion operation after the burners ( 4 ) are extinguished.

What is claimed is: 
     
         1 . A combustion device comprising: a burner which generates heat for heating a target fluid by a combustion operation; a fuel supply unit which supplies a fuel to the burner; a combustion fan which supplies air for combustion to the burner; and a control unit which has a function for determining a required amount of heat for temperature control of the target fluid and for controlling the fuel supply unit and the combustion fan according to the required amount of heat,
 wherein the control unit is configured to be capable of performing ON-OFF combustion control processing, which is processing for controlling the fuel supply unit and the combustion fan so as to intermittently perform the combustion operation of the burner, and is also configured to control the fuel supply unit and the combustion fan so as to change an amount of a fuel to be supplied to the burner and a number of rotations of the combustion fan according to the required amount of heat for temperature control of the target fluid at the time of igniting the burner to restart the combustion operation of the burner after the burner is extinguished in the ON-OFF combustion control processing.   
     
     
         2 . The combustion device according to  claim 1 ,
 wherein the control unit has a function for detecting a degree of blockage of a supply/exhaust flow path, which is a flow path of air for combustion or combustion exhaust gas, while operating the combustion fan at a predetermined number of rotations in an extinguished state of the burner in the ON-OFF combustion control processing, and is configured to control the combustion fan so as to change the number of rotations of the combustion fan at the time of ignition following an extinguished state of the burner according to the required amount of heat for the temperature control of the target fluid and the degree of blockage in a case where at least the degree of blockage is higher than a predetermined value.   
     
     
         3 . The combustion device according to  claim 1 ,
 wherein the control unit has a function for detecting a degree of blockage of a supply/exhaust flow path, which is the flow path of air for combustion or combustion exhaust gas, while operating the combustion fan at a predetermined number of rotations in an extinguished state of the burner in the ON-OFF combustion control processing, and is configured to control, in a case where the degree of blockage is lower than a predetermined value, the fuel supply unit and the combustion fan so as to change the amount of a fuel to be supplied to the burner and the number of rotations of the combustion fan according to the required amount of heat for the temperature control of the target fluid at the time of igniting the burner to restart the combustion operation of the burner after the burner is extinguished, and to control, in a case where the degree of blockage is higher than a predetermined value, the fuel supply unit so as to set the amount of a fuel to be supplied to the burner at the time of igniting the burner to restart the combustion operation of the burner after the burner is extinguished to a predetermined amount, and to control the combustion fan so as to set the number of rotations of the combustion fan to a number of rotations set according to the degree of blockage.   
     
     
         4 . The combustion device according to  claim 1 ,
 wherein the control unit is configured to control, in a case where the ignition of the burner is not detected at the time of igniting the burner to restart the combustion operation of the burner after the burner is extinguished, the fuel supply unit and the combustion fan so as to increase the amount of fuel to be supplied to the burner and the number of rotations of the combustion fan as compared with the time of ignition at which the ignition was not detected.   
     
     
         5 . The combustion device according to  claim 2 ,
 wherein the control unit is configured to control, in a case where the ignition of the burner is not detected at the time of igniting the burner to restart the combustion operation of the burner after the burner is extinguished, the fuel supply unit and the combustion fan so as to increase the amount of fuel to be supplied to the burner and the number of rotations of the combustion fan as compared with the time of ignition at which the ignition was not detected.   
     
     
         6 . The combustion device according to  claim 3 ,
 wherein the control unit is configured to control, in a case where the ignition of the burner is not detected at the time of igniting the burner to restart the combustion operation of the burner after the burner is extinguished, the fuel supply unit and the combustion fan so as to increase the amount of fuel to be supplied to the burner and the number of rotations of the combustion fan as compared with the time of ignition at which the ignition was not detected.