| 摘要 |
Fibrous mat type burner can have mat pieced together with butt joints and very thin layer of resinous sealant uniting the pieces at the joint. Burners with elongated mats are thus readily manufactured, and can be packaged strapped together in pairs face-to-face and enclosed in telescoping carton halves that allow for packaging burners of different lengths. Simple cushioning strips such as of folded corrugated cardboard can be inserted between burner faces, and cushioning pads over outer edges of burner backs, before they are strapped together. Holes can be provided in the cushioning strips to hold them in place over fastener heads projecting from burner face. Burners with hat-shaped mats for enveloping and brazing heat-exchange tubes to tube sheet can be used individually or in pairs to effect such brazing on tube-and-sheet assemblies secured on rotating table and indexed into position under burners. Suction ring around bottom of burner draws off some hot combustion gases generated in burner. Lowering and raising of burner over top of tube-and-sheet assembly, as well as of suction head against bottom of tube-and-sheet assembly is conveniently effected using large-diameter suction piping with loose joints that allow pipe rotation to accomodate such movement. The tubes can be staked or expanded where they penetrate the tube sheet, to reduce the clearance between them.
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