| 摘要 |
PURPOSE:To prevent a malfunction due to the fluctuation of combustion flame and detect an oxygen shortage condition surely by a method wherein an oxygen concentration cell element of a cylindrical form is planted in a cavity at the center of flame ports of both sides formed on a pilot flame. CONSTITUTION:When the pilot flame 4 is ignited, an oxygen concentration cell element 10 is heated from both sides of outer peripheral surfaces thereof by combustion flames from flame ports 8, 8 and an electromotive force in accordance with a difference of densities of atmospheric oxygen contacting electrode surfaces 10a, 10a at both inner and outer peripheral surfaces of the same element 10 is generated. Accordingly, a safety valve 2 is kept in an open valve condition. On the other hand, when the combustion is turned into an incomplete combustion due to an oxygen shortage condition, the combustion flame is extended upwardly and an opening 11 at an upper end of the element 10 is covered by the combustion flame, then, combustion gas is flowed into the element 10 through this opening 11. Due to this phenomenon, the electrode surface 10a at the inner periphery of the element 10 is placed in an atmosphere of the low oxygen density and the difference of the oxygen densities is decreased, thus, the electromotive force is decreased and a safety valve 2 is closed. |
