| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a flame sensor that reliably discriminates the presence of flames and activates a fire alarm without a malfunction due to arc welding light, by enhancing the discriminability between flames and arc welding light. <P>SOLUTION: A first optical filter 14a selectively transmits light that is emitted by CO<SB POS="POST">2</SB>resonance generated in flame combustion and has a narrow band of wavelength with the center wavelength of about 4.5 μm. A first light receiving element 16a converts the light into an electric signal to output a 4.5 μm light reception signal e1. A second optical filter 14b transmits light of a near-infrared wavelength band of about 0.7 to 1.0 μm included in arc welding light. A second light receiving element 16b converts the light into an electric signal to output a near-infrared light reception signal e2. A flame determination part 26 discriminates and determines the presence of flames and a radiation source of arc welding light on the basis of the 4.5 μm light reception signal e1 and the near-infrared light reception signal e2, and when determining the presence of flames, operates an alarm circuit 28 to output a fire alarm signal. <P>COPYRIGHT: (C)2013,JPO&INPIT |
