The combustion apparatus in an embodiment of the present invention is a hot water supply apparatus of the roof top flue type (RF type), which is installed outdoor and uses the outside air as the combustion air of the burner. As shown in
An air supply port 7 and an exhaust port 8 are provided on a side surface of the cabinet 1a, and combustion air of the burner 3 is taken in from the air supply port 7 by use of the fan 4. The gas detection means 5 is positioned between the air supply port 7 and the fan 4. The combustion chamber 1b communicates with the exhaust port 8, and a combustion exhaust gas burned by the burner 3 is exhausted from the exhaust port 8.
The combustion control means 60 of the controller 6 performs prepurge, which involves exhausting air from the combustion chamber 1b by rotating the fan 4 by the energization of the motor 4a, and thereafter performs combustion operation by igniting the burner 3 by use of an igniter 3a.
The controller 6 comprises alarm means 61 for giving the user an alarm indicating that a combustible gas is present by an alarm sound, by the lighting of an alarm lamp and the like when a combustible gas of a preset maximum concentration or higher has been detected by the gas detection means 5. Because of this, the user can take measures, such as the removal of an item that provides a source of generation of the combustible gas in the vicinity of the air supply port 7 and can further increase safety. The maximum concentration is set at a value lower than the concentration at which the combustible gas in question catches fire.
The controller 6 comprises caution means 62 for arousing caution by making it known to the user by an unillustrated caution buzzer, by the lighting of an unillustrated caution lamp and the like that a combustion gas which is in a range that is higher than a minimum concentration set lower than the maximum concentration and is lower than the maximum concentration has been detected during combustion operation by the gas detection means 5 when this combustible gas in the range has been detected. Because of this, when there is an item that causes the generation of a combustible gas, such as a tank of a volatile fuel, such as gasoline, in the vicinity of the air supply port 7, the user can take measures, such as the removal of the item, and can prevent the concentration of the combustible gas present in the vicinity of the air supply port 7 from becoming greater than the maximum concentration.
Next, the operation of the controller 6 will be described with reference to
When the application of water to the hot water supply apparatus 1 has been detected by a water application sensor that is not illustrated, the combustion control means 60 of the controller 6 ascertains at STEP 1 whether a combustible gas of the maximum concentration or higher is detected by the gas detection means 5. When a combustible gas of the maximum concentration or higher has been detected, the operation proceeds to STEP 2, at which the combustion control means 60 prohibits prepurge without allowing the energization of the motor 4a. And at STEP 3, the alarm means 61 gives an alarm to the user. As a result of this, it is possible to positively prevent the combustible gas from catching fire from an electric spark that might be generated in association with the energization of the motor 4a and the ignition of the burner 3 by the igniter 3a.
When a combustible gas of the maximum concentration or higher has not been detected by the gas detection means 5 at STEP 1, the operation proceeds to STEP 4 in a branching manner, and the combustion control means 60 starts prepurge, which involves exhausting air from the combustion chamber 1b by rotating the fan 4 for a prescribed time. And at STEP 5, the combustion control means 60 ascertains, during the prepurge, whether a combustible gas of the maximum concentration or higher is detected by use of the gas detection means 5. When a combustible gas of the maximum concentration or higher has been detected, the operation proceeds to STEP 6, at which the combustion control means 60 prohibits the ignition of the burner 3. And at STEP 7, the alarm means 61 gives an alarm to the user. As a result of this, it is possible to positively prevent the combustible gas from catching fire in association with the ignition of the burner 3.
On the other hand, when a combustible gas of the maximum concentration or higher has not been detected by the gas detection means 5 at STEP 5, the operation proceeds to STEP 8 in a branching manner, and the combustion control means 60 ascertains whether a combustible gas which is in a range that is higher than a minimum concentration (for example, 0%) set lower than the maximum concentration and is lower than the maximum concentration is detected by use of the gas detection means 5. When a combustible gas in the range has been detected, the operation proceeds to STEP 9, at which the caution means 62 arouses the user's caution and the combustion control means 60 extends the prescribed time for which prepurge is performed.
Next, at STEP 10, the combustion control means 60 ascertains within the extended, prescribed time whether a combustible gas of the maximum concentration or higher is detected by the gas detection means 5. When a combustible gas of the maximum concentration or higher has been detected, the operation proceeds to STEP 6, at which the combustion control means 60 prohibits the ignition of the burner 3. By ensuring that the prescribed time is extended like this at STEP 9, even when the concentration of a combustible gas increases during the prepurge, it is possible to ascertain over a sufficient period of time whether the concentration of a combustible gas increases until the maximum concentration is exceeded. Therefore, it is possible to prevent more positively the combustible gas from catching fire due to the ignition of the burner 3.
When the concentration of a combustible gas detected by the gas detection means 5 at STEP 8 is not in the range that is higher than a minimum concentration set lower than the maximum concentration and is lower than the maximum concentration, the operation proceeds to STEP 11 in a branching manner, and the combustion control means 60 ascertains whether the prescribed time has elapsed. When the prescribed time has elapsed, the operation proceeds to STEP 12, at which the combustion control means 60 finishes the prepurge. At STEP 13 the burner 3 is ignited by the igniter 3a, and at STEP 14 the combustion operation of the burner 3 is performed. On the other hand, when the prescribed time has not elapsed at STEP 11, the operation returns to STEP 5.
When a combustible gas of the maximum concentration or higher has not been detected at STEP 10, the operation proceeds to STEP 15 in a branching manner, and the combustion control means 60 ascertains whether the extended, prescribed time has elapsed. The operation proceeds to STEP 12 when the extended, prescribed time has elapsed, and the operation returns to STEP 10 when the extended, prescribed time has not elapsed.
Next, the operation of the controller 6 during combustion operation will be described with reference to
When combustion operation has been started, the combustion control means 60 ascertains at STEP 21 whether a combustible gas of the maximum concentration or higher is detected by use of the gas detection means 5. When a combustible gas of the maximum concentration or higher has been detected, the operation proceeds to STEP 22, at which the combustion control means 60 stops the combustion of the burner 3 by interrupting the fuel gas being supplied to the burner 3. And at STEP 23, the alarm means 61 gives an alarm to the user.
When a combustible gas of the maximum concentration or higher has not been detected by the gas detection means 5 at STEP 21, the operation proceeds to STEP 24 in a branching manner, and the combustion control means 60 ascertains whether a combustible gas which is in a range that is higher than a minimum concentration set lower than the maximum concentration and is lower than the maximum concentration is detected. When a combustible gas of the concentration in the range has been detected, the operation proceeds to STEP 25, at which the caution means 62 arouses the user's caution and the operation returns to STEP 21. Because of this, the user can take measures, such as the removal of an item that provides a source of generation of the combustible gas in the vicinity of the air supply port 7, and can prevent the concentration of the combustible gas present in the vicinity of the air supply port 7 from becoming higher than the maximum concentration. On the other hand, when a combustible gas of the maximum concentration or higher has not been detected at STEP 24, the operation returns to STEP 21.
According to the hot water supply apparatus 1 of this embodiment, even when a combustible gas is present in the vicinity of the air supply port 7, by use of the gas detection means 5 disposed between the air supply port 7 and the fan 4, it is possible to detect the concentration of a combustible gas that has entered from the air supply port 7, and it is possible to positively prevent a combustible gas from caching fire.
In this embodiment, the description has been made of a case where a hot water supply apparatus of the roof top flue type (RF type), which is installed outdoor and uses the outside air as the combustion air of the burner, is used as the combustion apparatus. However, the present invention is not limited to this, and the effects of the present invention can also be obtained similarly in a hot water supply apparatus of an indoor installation type, such as the forced draft balanced flue type (FF type) and the forced exhaust type (FE type).
Number | Date | Country | Kind |
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2006-115561 | Apr 2006 | JP | national |