| 摘要 |
PURPOSE:To prevent backfire and make it possible to provide always and stably surface combustion regardless of the variation in supply amount of a premixing gas by providing a metal net through which the premixing gas passes at the downstream side of a mixing chamber where a combustion gas and air are mixed and mounting a cooling pipe through which a cooling fluid passes and which cools the metal net. CONSTITUTION:A metal net 10 is provided at the downstream side of a mixing chamber 9, and a cooling pipe 11 is fixed on to the net. The metal net 10 is cooled by a cooling pipe 11 through which a cooling fluid passes to maintain a premixing gas passing through the net meshed at a temperature below the ignition temperature. When the amount of the premixing gas being supplied is made small and the supply rate is lowered in order to lower the combustion temperature at the burner A, the position of ignition in the combustion chamber 12 is gradually moved toward the premixing chamber 9, but since the premixing gas temperature is maintained at a temperature below the ignition temperature, the premixing gas passing through the metal net 10 does not ignite. Consequently there is no ignition of the premixing gas in the mixing chamber 9 and backfire is, therefore, prevented. |
