Heat exchanger and a method for a liquid-tight mounting of an end plate to an array heat exchanging elements of the heat exchanger

摘要

Disclosed is a heat exchanger assembled of a plurality of oval heat exchanging pipes whose end portions are mounted in a leakage proof manner in oval openings of top and bottom plates. The ratio of maximum and minimum diameters of intermediate portions of the pipes if 2.5:1 through 8:1 whereas the ratio of the maximum and minimum diameters of the oval openings in the end plates is 1.2:1 through 3:1. A method of mounting the pipe end portions in the oval openings is based on a preliminary shaping of the end portions by the application of pressure from the outside toward the center axis of the end portions in the direction of their maximum diameter. The preshaped end portions are inserted into sealing collars surrounding the edges of respective plate openings. Thereafter the end portions are expanded by means of mandrels to sealingly close the openings.