US 5,205,038 AGranted

Method of replacing a tube on a straight-tube heat exchanger

AssigneeFramatome

InventorsJacques Archer, Georges Moreau, Daniel Besson, Benoit Giraud

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Abstract

A transverse cut (18, 19) is made on a heat exchanger tube (4) to be replaced in the vicinity of its connectors (14, 15), at each end. A cut (19') is made in the frustoconical zone (16') of connection of the tube (4) to the second connector (15). The cutting operations are effected from inside the tube (4) and through one of the tube plates (2, 3). The tube (4) to be replaced is extracted from the heat exchanger through the interior of the second connector (15) and the corresponding opening (13) in the second tube plate (3). A replacement tube is introduced into the heat exchanger through the opening (13) in the second tube plate (3) until a first end of the tube engaged in the heat exchanger reaches the level of the cut zone (18) of the first connector (14). The first end of the tube is welded on the first connector (14). The length of the replacement tube is adjusted so that its second end can be engaged in the second connector (15) over a predetermined length, and the second end of the replacement tube is joined by an overhang weld inside the second connector (15).

Method of replacing a tube (4) of a straight-tube heat exchanger comprising first and second substantially parallel tube plates 2, 3) spaced apart from one another and having, extending through them, openings (12, 13) at which tubes (4) are fixed at ends of said tubes by welding to connectors (14, 15), each of said tubes of a heat exchanger bundle having a first end fixed on a first connector (14) of said first tube plate (2), and a second end fixed on a second connector (15) of said second tube plate (3), an inside diameter of at least one of the connectors or second connector (15) and of a corresponding opening of the second tube plate (3) being substantially greater than an outside diameter of said tube (4) which is connected to said second connector (15) by a junction zone (16') of substantially frustoconical shape, said method comprising the steps of

(a) cutting said tube (4) transversely in the vicinity of the connectors (14, 15), at each end, from the interior of said tube (4) and through one of said tube plates (2, 3);
(b) cutting and extracting from the heat exchanger space between tube plates, the junction zone (16') connecting said tube (4) to the second connector (15);
(c) extracting said tube from said heat exchanger space between said tube plates (2, 3), through the interior of the second connector (15) and through a corresponding opening (13) in said second tube plate (3);
(d) cleaning and remachining zones (18, 19') of the connectors where the cuts were made;
(e) introducing a replacement tube (34) into said heat exchanger by way of the opening (13) in said second tube plate until a first end of said replacement tube (34) first engaged in said heat exchanger reaches the level of the cut zone (18) of said first connector (14);
(f) joining the first end of said replacement tube (34) to said first connector (14) by an overhang weld;
(g) adjusting the length of said replacement tube (34) so that its second end (34b) is engaged over a predetermined length in said second connector (15);
and
(h) joining the second end of said replacement tube (34) to the interior of said second connector (15) by an overhang weld.

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Abstract

Claims8