| 摘要 |
PURPOSE:To improve the reliability of the prepurging operation of the titled device by a method wherein in case a residual fuel in a combustion chamber, is prepurged by supplying air into, and discharging from, the combustion chamber by use of a blower prior to combustion, a detector for detecting the number of revolutions of the blower is provided so that a combustion operation is started in response to a detecting signal from the detector. CONSTITUTION:When the impeller 13 of the blower 5 of the combustion device is rotated by a motor 11 prior to combustion, combustion air is sucked into the combustion chamber 2 and is then discharged through an exhaust cylinder 6 to thereby prepurge the chamber. In this case, a light shielding plate 14 provided with holes 15 at predetermined positions, respectively, is attached to one end of the rotary shaft 12 of the motor 11 and the rotation detector 16 having a photo emmissive element 17 and a photo receiving element 18 on the opposing surfaces thereof, respectively, are provided. With the above structure, the light generating from the photo emmisive element 17 is applied upon the photo receiving element 18 only when the holes 15 in the shielding plate is brought in line with the elements 17 and 18 due to the rotation of the light shielding plate 14, so that a pulse current flows through the rotation detector to detect the number of revolutions of the blower 5 and the combustion operation of the device is started in response to the detecting signal from the rotation detector. |
