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

Claim 1

A method of liquid-tight mounting of an end plate to a plurality of heat exchanging tubes having substantially oval cross-sections having first maximum diameters, first minimum diameters, and first ratios of the first maximum diameters to the first minimum diameters of 2.5:1 to 8:1, said method comprising the steps of providing the end plate with a plurality of openings for receiving the heat exchanging tubes; providing a plurality of sealing elements extending into said plurality of openings and defining elastically deformable and substantially oval passages having in an undeformed condition of said sealing elements second maximum diameters and second minimum diameters; preshaping end portions of the heat exchanging tubes by applying outer pressure to the end portions in a direction of the first maximum diameters to reduce the first maximum diameter to a third maximum diameter and to increase the first minimum diameter to a third minimum diameter at the end portions without substantial change of the circumferences of said end portions and such that said end portions can be inserted into said passages without substantial stress and force; thereafter inserting the end portions of the heat exchanging tubes into the elastically deformable passages of said plurality of sealing elements; and then providing liquid-tight and mechanically stable connections of the end portions of said heat exchanging tubes with the end plate by expanding the end portions and said sealing elements in all directions from inside thereof in such a way that its cross-sections substantially remain oval, have fourth maximum diameters greater than said second maximum diameters and fourth minimum diameters greater than said second minimum diameters, and have second ratios of the fourth maximum diameters to the fourth minimum diameters of 1.2:1 through 3:1, the first ratios being always larger than the second ratios.

Claim 2

A method of liquid-tight mounting of an end plate to a plurality of heat exchanging tubes having substantially oval cross-sections having first maximum diameters, first minimum diameters, and first ratios of the first maximum diameters to the first minimum diameters of 2.5:1 to 8:1, said method comprising the steps of providing the end plate with a plurality of openings for receiving the heat exchanging tubes; providing a plurality of sealing elements extending into said plurality of openings and defining elastically deformable and substantially oval passages having in an undeformed condition of said sealing elements second maximum diameters and second minimum diameters; preshaping end portions of the heat exchanging tubes by applying outer pressure to the end portions in a direction of the first maximum diameters to reduce the first maximum diameter to a third maximum diameter and to increase the first minimum diameter to a third minimum diameter at the end portions without substantial change of the circumferences of said end portions and such that said end portions can be inserted into said passages without substantial stress and force; thereafter inserting the end portions of the heat exchanging tubes into the elastically deformable passages of said plurality of sealing elements; and then providing liquid-tight and mechanically stable connections of the end portions of said heat exchanging tubes with the end plate by expanding the end portions and said sealing elements in all directions from inside thereof in such a way that its cross-sections substantially remain oval, have fourth maximum diameters greater than said second maximum diameters and fourth minimum diameters greater than said second minimum diameters, and have second ratios of the fourth maximum diameters to the fourth minimum diameters of 1.2:1 through 3:1, the first ratios being always larger than the second ratios.