| 摘要 |
1469656 Making heat exchangers CIBAGEIGY AG 18 Feb 1975 [14 March 1974] 11312/74 Heading B3A [Also in Divisions B5 and F4] A method of making a heat exchanger comprising a conduit having a plurality of passes joined by integral return bends comprises producing two strips of material placed together in zigzag formation to form a stack of substantially parallel passes, the two strips being relatively displaced in the direction of the passes to leave a clearance between the bend peaks, bonding the strips together along lines substantially parallel to their longitudinal edges to form a flat serpentine conduit, and inflating the conduit by internal fluid pressure. The strip may be of copper, mild steel, aluminium, or aluminium alloy. The strip may be bonded by welding, soldering or brazing, using a release agent or stop-weld in those areas which are to be inflated. The strips may be bonded by a thermosetting adhesive, e.g. epoxide resins or phenolic resins, and the latter may contain an elastomer such as nitrile rubber or a thermoplast, e.g. nylon or a vinyl polymer. Alternative adhesives are natural or synthetic rubbers such as chlorinated, nitrile, or polysulphide rubbers, or thermoplastic adhesives such as poly-(vinyl acetate), poly-(vinyl chloride), polyacrylates, and polyamides. The stack shown in Fig. 2 may be produced by folding together strips 21, 22 and then pulling them apart, or folding the strips separately and interfitting them, or folding them together but displaced. The resulting stack is bonded, usually under pressure and heat, using spacers 23 of twice the strip thickness, (e.g. strip material doubled) at the bends. The stack may then be cut to produce a flat conduit of the required size, which is then assembled with tool pieces 41, and one or both ends connected to a pressure source to form the inflated conduit. The pattern of adhesive or stop-weld may be such as to produce a single channel along the strip, or plural channels, or plural interconnected channels, and a channel may be sinuous. In a final step, fin pieces 51 are placed between the conduit passes and fixed by adhesive. Alternatively these may be inserted before inflation of the conduit, and gripped by such inflation. |
