| 摘要 |
PURPOSE:To enable the checking for flame depending on infrared rays emitted from a combustion gas of the flame by providing an infrared ray detection element for detecting infrared rays emitted from the combustion gas at the position allowing the detection of the combustion gas and a comparator which provides the flame detection output when the pulsating output exceeds a specified value. CONSTITUTION:As a flame 5 ignites in a burner 2, a high temperature combustion gas is generated at the top of the flame 5. This combustion gas pulsates depending on the flow and the temperature thereof and the infrared rays emitted pulsate. When the infrared rays are detected with an infrared ray detection element 1, the detection intensity involves a pulsation. Only alternating components of the pulsation are amplified with an amplifier 8 after the removal of low frequency noise components with a high pass filter and further, rectified with a rectifying element 13 and a capacitor 14. The resultant rectification output is compared with a specified voltage determined by the division of resistances 16 and 17 with a comparator 15, which outputs a flame detection signal when the rectification output exceeds the specified value and a relay 18 is turned ON to send the flame detection signal. |
