| 摘要 |
A method for controlling, in the manufacture of plate fin and tube heat exchangers, the operation of a tube expander of the type that does not expand all hairpin tubes in a heat exchanger simultaneously so that the two legs of each hairpin tube are expanded at the same time. In a preferred embodiment, a supply of pressurized air is directed through one of a selected group of open ended tube legs. Pressure sensors located at the ends other legs within the group detect the tube, if any, at which there an increase in pressure, establishing continuity between that leg and the first leg and thus identifying the two legs under test as parts of the same hairpin. This matched pair of legs is identified for expansion on the same expansion stroke of the expander. Other legs within the group between which there is pressure continuity are similarly detected and identified. Other groups of legs are similarly and progressively selected and matched pairs identified until all matched pairs in the heat exchanger have been identified and expanded.
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