JPS58187797A - Tube plate structure for heat exchanger - Google Patents

Abstract

PURPOSE:To enable to simply butt-welding a tube plate to a tube by arranging a groove on the periphery of the holes of the plate and forming the part of the same section as the tube at the periphery of the holes, thereby obtaining the similar effect to a stab. CONSTITUTION:A hole which has the same diameter as the inner diameter of a tube which is connected first to a tube plate 1. A groove 8 is formed by a bite 7 in space at a distance corresponding to the thickness of the tube 2 from the end of the hole. The part of the same section as the tube 2 is formed at the periphery of the hole. The tube 2 is welded at 4 to the part. In this manner, a cylinder 9 which is split is inserted into the groove 8, thereby readily axially matching the tube 2 to the hole of the plate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat exchanger, and relates to a leak-proof tube sheet structure suitable for preventing corrosion in gaps between tubes and tube sheets.

Conventionally, in heat exchangers, tubes are inserted into tube holes in the tube sheet.
A structure in which the tubes are expanded and joined by welding has been used, but for example, in steam generators used in fast breeder reactors, there is a problem of corrosion between the tubes and tube sheets due to the sodium atmosphere.
In order to prevent reactions between sodium and water, a leak-proof structure in which the tube and tubesheet are butt-welded on the body side of the tubesheet has been required.

However, when welding a tube and a tube sheet, it is difficult to weld the tube directly to a thick tube sheet because of the large difference in heat capacity, making it difficult to obtain a good weld. Therefore, conventionally, Figure 1
As shown, a method is used in which a protrusion, that is, a stub (3) having the same cross section as the tube (2) is formed on the tube plate (ω), and this and the tube (2) are welded in a separate process.

■Method of cutting by machining, 2), Fig. 2(a)
) As shown here, there is a method of finishing the stub by covering the area that matches the hole in the tube plate.

However, method 1) is disadvantageous in terms of man-hours and cost, and method 2) has extremely low toughness of electroslag welded metal as welded, so normalizing and tempering treatments are required to improve toughness. Considering such post-processing, washing with water also poses problems in terms of man-hours and cost.

Furthermore, the star structure described above also has the disadvantage that it is difficult to align the axes of the tube and the tube plate.

The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to obtain the same effect as J' by using a tube plate structure in which the tube plate and the tube can be butt welded easily.

The present invention will be explained based on Embodiment 1 with reference to the drawings.

3 to 5 are sectional views showing an embodiment of the present invention. In FIG. 3, a hole having the same diameter as the inner diameter of the pipe to be connected is first bored in the tube plate (1). Next, tube G from the end of this hole? )
Cut the groove (8) using (7) at a distance corresponding to the wall thickness of the pie. Then put a tube around the hole. Groove (8
) width depends on the pitch of the tube group, but a curvature is provided to create the inside of the groove (2). A semicircle is preferable if possible.

FIG. 5 shows an example of the effect of the embodiment of the present invention.

The weld (4) between the tube (2) and the tube sheet ω is usually 'I' IO welded from the inner surface of the tube sheet ■, but in this case the weld between the tube ■ and the tube sheet (
It is necessary to fix the hole 1) so that it is on the concentric axis.

According to Motokawa's invention, by inserting the half-split base tube 9 into the groove (8), the axes of the tube (2) and the hole in the tube plate (2) can be easily aligned.

According to the present invention, when manufacturing a heat exchanger with a leak-proof structure, there is no need for a large amount of cutting to form conventional stubs, and there is no problem of insufficient toughness due to electroslag, and extremely flat holes are formed. Machining and grooving around the stub form a part equivalent to a stub, which greatly reduces man-hours.Furthermore, when TIG welding the tube and tube plate, the groove can be used to facilitate alignment of the axes of the hole and tube. And there is something great about Yoshu.

[Brief explanation of the drawing]

1 and 2 show a conventional method of forming a stub in a tube sheet having a leak-proof structure, and FIGS. 3 to 5 show cross-sectional views of an embodiment of the present invention. (]): Tube plate, (2): Pipe, ■Nistab, (
4): Welded part, ■: Cut out part, (6): Electroslag, (7) Bihyde, ■: Groove, ■) Two-half cylinder.

Claims (1)

[Claims] In a leak-proof heat exchanger in which a tube is welded to a tube sheet, a hole with the same diameter as the inside diameter of the tube is bored in the tube sheet, a groove is provided around the hole, and the part between the hole and the groove is defined as the tube cross section. A tube sheet structure for a heat exchanger, characterized in that the tubes are made identical and butt welded thereto.