| 摘要 |
PURPOSE:To prevent large dispersion of oxygen density operating a cut-off device (ODS) upon oxygen deficiency by a method wherein the primary air control device consisting of shape memorizing alloy having a shape so as to close fully at a normal temperature and to open fully at a set temperature or above is fitted to the primary air holes of a premixing type burner. CONSTITUTION:A shape-change is memorized so as to close the primary air holes 5 at the set temperature or under and to open the primary air holes 5 at the set temperature or above by the shape memorizing alloy. When a pilot burner is ignited with an ignition plug 4, a thermo-couple 3 is heated by the flame thereof and a safety valve is opened by electromotive force thereof to continue the combustion. The operation of the ODS fitting place is worked at the set value or above, therefore, the primary air control device 2 is opening condition. However, the oxygen density at the installation room of a gas utensil decreases from 19% for some cause and the flame of the pilot burner 7 is blown off while the temperature of the ODS installation place descends from the set value and the primary air holes 5 is closed by the primary air control device 2. Accordingly, the thermo-couple 3 loses the electromotive force and the safety valve is closed, therefore, the combustion of the utensil may be stopped.
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