Combustion device and hot water device including same

Abstract

A combustion device includes a fan; a premixing device capable of generating an air-fuel mixture by driving the fan; and an ignition device capable of ignition operation for the air-fuel mixture in a combustion chamber. The premixing device includes a flapper capable of opening and closing a part of a gas flow path and has a larger opening degree when the drive speed of the fan is high speed than low speed. The ignition operation for the air-fuel mixture by the ignition device is a standard ignition operation in principle, executed in a first drive speed range of the fan in which the flapper is in an open state, and exceptionally a non-standard ignition operation, executed in a second drive speed range of the fan in which the flapper is in a closed state in the case where the air-fuel mixture is not ignited by the standard ignition operation.

What is claimed is: 
     
         1 . A combustion device, comprising: 
 a variable-speed fan;   a premixing device having a gas flow path through which air flows internally by driving of the variable-speed fan, and a fuel gas outlet communicating with the gas flow path, in which fuel gas flows out from the fuel gas outlet into the gas flow path by negative pressure when the air flows through the gas flow path, and capable of generating an air-fuel mixture of the air and the fuel gas;   a combustion chamber positioned on an exhaust side of the variable-speed fan so as to receive supply of the air-fuel mixture, and for combusting the air-fuel mixture; and   an ignition device capable of ignition operation for the air-fuel mixture in the combustion chamber,   wherein the premixing device includes a flapper capable of opening and closing a part of the gas flow path, and an opening degree of the flapper is larger in a case of a drive speed of the variable-speed fan being high speed than in a case of being low speed, and   the ignition operation for the air-fuel mixture by the ignition device is configured as: 
 a standard ignition operation in principle, which is executed in a first drive speed range of the variable-speed fan in which the flapper is in an open state, and exceptionally a non-standard ignition operation, which is executed in a second drive speed range of the variable-speed fan in which the flapper is in a closed state in a case where the air-fuel mixture is not ignited by the standard ignition operation. 
   
     
     
         2 . The combustion device according to  claim 1 , wherein 
       the non-standard ignition operation is configured to be executed in a state where the drive speed of the variable-speed fan is set to a highest speed range of the second drive speed range. 
     
     
         3 . The combustion device according to  claim 1 , 
       wherein the first drive speed range includes a specific speed range in which the flapper is in a partially open state, and 
       the standard ignition operation is configured to be executed in a state where the drive speed of the variable-speed fan is set to a highest speed range of the specific speed range, or a speed range equal to or higher than the highest speed range. 
     
     
         4 . The combustion device according to  claim 1 , 
       wherein in a case where the ignition operation for the air-fuel mixture is executed, the standard ignition operation is executed a number of times equal to or less than a predetermined first upper-limit number of times until the air-fuel mixture is ignited, and in a case where the air-fuel mixture is not ignited regardless of the standard ignition operation being executed the first upper-limit number of times, the non-standard ignition operation is executed thereafter. 
     
     
         5 . The combustion device according to  claim 4 , 
       wherein in a case where the standard ignition operation is executed a plurality of times repeatedly, the drive speed of the variable-speed fan gradually increases. 
     
     
         6 . The combustion device according to  claim 1 , 
       wherein in a case where the air-fuel mixture is not ignited regardless of the non-standard ignition operation being executed repeatedly for a predetermined second upper-limit number of times, it is determined that an abnormality has occurred, and no ignition operations continuously executed thereafter. 
     
     
         7 . The combustion device according to  claim 1 , 
       wherein in a case where the standard ignition operation and/or the non-standard ignition operation is executed repeatedly, an interval period is secured, and during the interval period, the variable-speed fan is driven at a higher speed than a drive speed during the standard ignition operation and the non-standard ignition operation, and a scavenging process of the combustion chamber is executed. 
     
     
         8 . The combustion device according to  claim 1 , comprising: 
 a setting part capable of selecting and setting a specific ignition operation mode as the ignition operation for the air-fuel mixture,   wherein in a case where the specific ignition operation mode is set in the setting part, the standard ignition operation is omitted in executing the ignition operation for the air-fuel mixture and the non-standard ignition operation is executed.   
     
     
         9 . A hot water device, comprising: 
 a combustion device; and   a heat exchanger capable of heating hot water using combustion gas generated by the combustion device,   wherein the combustion device according to  claim 1  is configured as the combustion device.   
     
     
         10 . A hot water device, comprising: 
 a combustion device; and   a heat exchanger capable of heating hot water using combustion gas generated by the combustion device,   wherein the combustion device according to  claim 2  is configured as the combustion device.   
     
     
         11 . A hot water device, comprising: 
 a combustion device; and   a heat exchanger capable of heating hot water using combustion gas generated by the combustion device,   wherein the combustion device according to  claim 3  is configured as the combustion device.   
     
     
         12 . A hot water device, comprising: 
 a combustion device; and   a heat exchanger capable of heating hot water using combustion gas generated by the combustion device,   wherein the combustion device according to  claim 4  is configured as the combustion device.   
     
     
         13 . A hot water device, comprising: 
 a combustion device; and   a heat exchanger capable of heating hot water using combustion gas generated by the combustion device,   wherein the combustion device according to  claim 5  is configured as the combustion device.   
     
     
         14 . A hot water device, comprising: 
 a combustion device; and   a heat exchanger capable of heating hot water using combustion gas generated by the combustion device,   wherein the combustion device according to  claim 6  is configured as the combustion device.   
     
     
         15 . A hot water device, comprising: 
 a combustion device; and   a heat exchanger capable of heating hot water using combustion gas generated by the combustion device,   wherein the combustion device according to  claim 7  is configured as the combustion device.   
     
     
         16 . A hot water device, comprising: 
 a combustion device; and   a heat exchanger capable of heating hot water using combustion gas generated by the combustion device,   wherein the combustion device according to  claim 8  is configured as the combustion device.