| 摘要 |
A burner assembly (10) for a radiant heater of the infrared type. The burner assembly includes a burner tube (12), a generally cylindrical mixing cup assembly (14), mounting means (16) for mounting the mixing cup assembly within the burner tube, means (18) for introducing air into the upstream end of the burner tube, and means (20) for introducing combustible gas into the burner cup, the gas and air being thoroughly mixed together in the burner cup. The mixing cup assembly includes a generally cylindrical mixer tube (32), and passageway means at the downstream end, the passageway means including a ceramic block (34) and a metallic grid (36) in contact with the downstream face of the ceramic block. The ceramic block has a plurality of relatively small orifices (34.1) which extend through the block. The metallic grid (36) has a plurality of relatively small apertures (36.3) and a large central aperture (36.4). The gas is introduced into the burner cup (14c) in such a manner that it will totally mix with a first air portion (primary air), the gas not spilling out of the burner cup. The thoroughly mixed air and gas will then pass through the orifices in the ceramic block with a relatively low pressure drop and through the apertures in the metallic grid. A second air portion (secondary air) flows about the mixing cup assembly. The grid serves as an ignition surface once a flame has been established. The foregoing design, which is of relatively low cost design achieving substantially complete combustion and correspondingly relatively low NOx and CO emissions, and a stable cylindrical flame for more uniform heating of a cylindrical burner tube.
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