PURPOSE: To contrive to maintain the constant sensitivity of a burning detecting sensor and the enlargement of a burning range by a method wherein a portion having variation of burning quantity is provided at a part of a flame hole of a surface burning burner so that the portion having no variation of burning quantity is formed by by-passing a fuel from an intermediate position between a fuel flow rate control valve and a governor.
CONSTITUTION: A by-pass conduit 16 is branched from an intermediate position between a governor 11 and a flow rate control valve 15, passed through a mixing chamber 5 of a burner, connected to a frame body 14. A frame rod 13 is provided at the upper part of a flame hole board 6 facing the frame body 14 as a burning detecting sensor. By said structure, a signal from the frame rod 13 due to the variation of burning quantity, that is, the variation of an ion electric current value Ifm hardly occurs. Therefore, the variation of a gas quantity supplied into the frame body 14 does not occur even when the burning gas quantity is varied by the flow rate control valve 15, accordingly, the gas quantity burnt at the upper part of the flame hole board 6 is not varied, also the ion electric current value obtained from the frame rod 13 provided at the upper part of the flame hole board is maintained at almost constant value, further, maintained at comparatively high level. Thereby, the ignition and mis-ignition of the burner can be detected steadily.
MORIYA YOSHIFUMI
INDOU MASAHIRO
