| 摘要 |
PURPOSE:To prevent flashback without degrading burning characteristics by providing a primary air restricting member around a nozzle in such a manner that it opens toward a secondary air passage only in a direction intersecting with the flowline of the passage. CONSTITUTION:Reference numeral 7 denotes the primary air restricting member, which is supported by the nozzle in an engagement therewith and connected fixedly to the front plate 5 of a burner. The opening direction of the restricting member 7 is perpendicular to the flowline of the secondary air passage 8 which is parallel to the axial line of the nozzle 2. Reference C denotes a combustion draft, B the flow of the secondary air, A the flow of primary air, and D the flow retracting the suctioned primary air at the time of extinguishment. With this construction, the primary air of the burner changes outside a flashback range both at the ignition and extinguishment times, thereby preventing effectively the occurrence of flashback. |
