| 摘要 |
Combustion apparatus (10) includes a combustion chamber (12, 212), a cover (24, 208) covering an end wall (14, 210) of the combustion chamber and defining a buffer space (26, 206) therebetween, and a blower (32, 202) external to the cover and supplying air to the buffer space and pressurizing the buffer space to a higher pressure than the combustion chamber such that leakage at penetrations (46) and/or interfaces (334, 336) flows from the buffer space into the combustion chamber, rather than the reverse, eliminating the need for leaktight seals, and instead permitting leakage in a desired direction. The sum of pressure drops (R1 + R2) from the blower to the mixer and burner assembly and from the mixer and burner assembly to the combustion chamber relative to that (R5) across the combustion chamber exhaust outlet (22, 220) is higher than the pressure drop (R3) from the blower to the buffer space relative to that (R4) across the buffer outlet (30) at the penetrations. In one embodiment, a first conduit (58) supplies air along a path (34) from the blower to the mixer and burner assembly without passing through the buffer space, and a second conduit (60) independently supplies air from the blower to the buffer space. A pressure dropping orifice (36) is provided between the blower and the mixer and burner assembly. A gas inlet port (40) is external to the cover (24) and downstream of the pressure dropping orifice (36). The buffer space (26) communicates with the blower (32) along an air flow path (44) upstream of the pressure dropping orifice (36). In another embodiment, air flows through the buffer space (206) to the mixer and burner assembly. The buffer space (26, 206) is thin and flat, and the cover (24; 208) covers only one end wall (14, 210) of the combustion chamber, not the other end wall nor the sidewall, such that the latter are accessible without removing the cover.
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