| 摘要 |
A method of assembling a plurality of microtubes rigidly into position so as to facilitate their rapid interference pressing into metallic header tubestrips is disclosed that is particularly well suited for the Microtube-Strip (MTS) gas-gas counterflow heat exchanger design. The technique, utilizing fusible alloys, non-sacrificial fixtures, and a high speed, gas powered machine gun tube insertion device, permits tube alignment, insertion, and welding rates to exceed 1,500,000 pieces per day per production line at greatly reduced costs. The following sequence of operations is followed: the tubes are finished to the required length; the tubes are inserted into adjacent, parallel, precision, non-sacrificial spacer forms, similar in size and pattern to the header tubestrips but with precision, slip-fit, countersunk holes; the spacer forms are slid apart to near opposite ends of the tubes; caps are placed over the ends of the tubes to secure the tube ends; the tube-spacer-cap fixture assembly is placed in a suitable mold; molten, fusible alloy is poured, or optionally it is vacuum-injected, into the heated mold; the mold is cooled below the solidus temperature; the encapsulated assembly is removed; the securing caps and spacer forms are slid off, exposing the tube ends; the assembly is loaded into a suitable fixture on a press and the header tubestrips are pressed onto opposite ends of the tubes; the fusible alloy is melted and cleaned from the assembly.
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