| 摘要 |
PURPOSE:To shorten the time for start up of combustion after ignition by connecting a blast volume control device to a blower by which the volume of blast is small in the initial stage when the use of the blower is started and the blast is increased to a specified volume for the constant operation. CONSTITUTION:The blast air is heated by a combustion means 2 to become a hot blast, and it is discharged from a discharge nozzle 29. Since right after the contact point on the side of a motor 18 is turned ON, the temperature near a thermistor 31 is as low as room temperature, the resistance in the thermistor 31 is maintained high and the input voltage to the motor 18 is lower and its rotational speed is kept low. The blast volume is thereby small and the gas concentration in a mixing chamber 8 is maintained high and the spread of combustion becomes fast. When the combustion by a combustion means 2 is further advanced, the air is heated by the combustion means 2 and the temperature is a little raised. Because the temperature near the thermistor 31 is also raised, its resistance value drops and the rotational speed of the motor becomes faster and the amount of blast increases. With this arrangement the time of start-up of combustion after ignition becomes shorter.
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