| 摘要 |
Method and apparatus for manufacturing a heat exchanger element which comprises a metal tube secured to a metal sheet by metal which has been heated and cooled. Wrinkles in the sheet after the tube has been joined thereto are removed by stretching at least the tube by an amount sufficient to cause the length of the tube to be substantially equal to the length of the outboard edges of the tube. The sheet may also be stretched beyond its elastic limit at the time that the tube is stretched but should not be stretched more than 2.5%. |
