JPS6210625Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an industrial heat exchanger including a steam generator, a heat exchanger for a nuclear power plant, and the like.

As an example of a heat exchanger tube support structure in a tube bundle structure of a conventional multi-tubular heat exchanger, a vertical cross-sectional view and a cross-sectional view of a heat exchanger having spiral heat exchanger tubes are shown in FIGS. 1a and 1b. The main body shell side consists of a shell 1, an upper flange 2, a lid flange 3, etc. The tube side is mainly composed of a tube group made up of a large number of spiral heat transfer tubes, only one of which is indicated by the reference numeral 19. In this example, a case is shown in which heat exchange is performed by flowing high-temperature fluid on the shell side and low-temperature fluid on the inside of the tube. The high temperature fluid flows through the nozzle 5, enters the annular header 10, and enters the annular header 1.
The holes distributed in the lower part of 0 reach the inner body side of the vessel. Thereafter, it flows down the outside of the tube group, reaches the lower part of the vessel, flows out from the nozzle 7, and enters the outlet pipe. On the other hand, the low-temperature fluid enters the annular header 8 from the nozzle 4, passes through the upper connecting pipes 11 (many) → straight pipes (descending pipes) 12 → lower connecting pipes 18, and reaches the spiral heat exchanger tubes 19. The heat rises within the spiral heat transfer 19 and flows out from the nozzle 6 via the outlet connecting pipe 20 and the outlet annular header 9. There are four types of spiral heat exchanger tubes 19 with different helical diameters, and the tubes with the same diameter are arranged on the same cylinder. In addition to this, the structure includes an inner tube 15, an outer tube (or cylindrical shroud) 13, a straight tube support 17 that supports the straight tube 12, and a tube group support provided in the radial direction between the inner tube 15 and the outer tube 13. There is a plate 14. The tube group support plate 14 has holes 16 through which each spiral heat exchanger tube 19 passes.
will be established.

Now, the straight downcomer pipe 12 must be supported at an appropriate pitch for earthquake resistance, and in this example, it is supported by a straight pipe support 17 welded to the outside of the outer cylinder 13. That is, the support 17 is a flange-shaped annular plate, and the downcomer pipe 12 is stopped from swinging by passing through a through hole formed in the support 17.

In such an example, the temperature of the downcomer pipe 12 is relatively low because it is close to the inlet of the low-temperature fluid, while the temperature of the outer cylinder 13 is approximately close to the average temperature of the inlet and outlet of the high-temperature fluid, so both There will be a significant temperature difference.

Therefore, since there is a relative difference in thermal expansion between the two, the downcomer pipe 12 is displaced in the axial direction with respect to the support 17 (sliding occurs). Moreover, the outer cylinder 13 also undergoes thermal expansion in its radial direction, and the downcomer pipe 12
produces a different thermal displacement (does not have the same radial elongation as the outer cylinder), resulting in a considerable surface pressure load between the support 17 and the downcomer pipe 12.

Due to the above-mentioned situation, the downcomer pipe 12 will suffer wear damage due to sliding at the support 17 portion, which will eventually lead to breakage of the pipe 12.

Although it is possible to select a wear-resistant material as the heat transfer tube material, this is often not always possible due to heat transfer properties and workability.

The present invention eliminates the above-mentioned drawbacks and provides a heat exchanger having a structure that does not cause wear damage due to sliding due to the difference in thermal elongation between the downcomer pipe and the downcomer support part. The purpose is

2 to 4 show examples of the present invention,
FIG. 2 shows a longitudinal section of a main part of the tube bundle structure, FIG. 3 shows a horizontal sectional view of the downcomer pipe support section, and FIG. 4 shows a horizontal sectional view of the tube bundle structure. The downcomer pipe 12 has omega-shaped support fittings 2 on the outer periphery of (four) support rings 23 provided at four locations in the vertical direction.
4 and bolts 27. bolt 2
7 is screwed into the screw hole of the support ring 23 and the support metal fitting 24 is strongly tightened, and then the head is spot welded and fixed to the support metal fitting 24. Radial keys 25 (flat plates extending vertically along the shroud) are welded to the inside of the support ring 23 at four locations in the circumferential direction at intervals of 90 degrees. On the other hand, a keyway metal fitting 26 (consisting of two parallel flat plates) is provided on the outer periphery of the shroud 13 in correspondence with the radial key 25. Radial key 25 and keyway metal fitting 2
6 indicates a fit with a predetermined tolerance.

When the steam generator with the structure of the present invention enters into operation, a vertical thermal expansion difference occurs between the shroud 13 and the downcomer pipe 12.
27 mostly moves together with the downcomer pipe 12, and sliding mainly occurs between the radial key 25 and the keyway fitting 26. The downcomer pipe 12 has a support ring 23
Since there is almost no sliding between the support fittings 24 and the supporting metal fittings 24, there is no risk of sliding wear and tear.

Furthermore, when a difference in thermal expansion occurs between the shroud 13 and the downcomer pipe 12 in the radial direction, the radial key 25 and the keyway fitting 26
Since the sliding occurs, the above-mentioned excessive surface pressure load is not applied to the downcomer pipe 12 as well as the radial key 25.

As mentioned above, vertical sliding occurs between the radial key 25 and the metal fitting 26, but since the materials of these two parts can be almost freely selected, it is best to make them wear-resistant. can. Therefore, the integrity of the steam generator can be maintained even during long-term use without significant wear and tear.

Regarding earthquake resistance, as shown in Figure 4,
The excitation force component in the X direction can be prevented by the radial key structure A and C, and the YY direction component can be prevented by B and D (not shown). In addition, for the vertical component, the total radial
This can be alleviated by the flat plate friction force of the key 25 (sufficient by design calculation).

As described above, a structure can be provided in which there is no sliding wear on the downcomer pipe 12 and the integrity of other parts is not impaired.

Note that the downcomer pipe 12 can be fixed to the support ring 23 not only by the method shown in FIGS. 2 to 4, but also by other various metal fittings. This fixing method is not relevant to the essence of the present invention.

[Brief explanation of the drawing]

Figures 1a and 1b are longitudinal and horizontal sectional views, respectively, of a conventional multi-tube heat exchanger, and Figures 2 to 4 are respective views of a multi-tube heat exchanger having a tube bundle structure according to the present invention. FIG. 1 is a longitudinal cross-sectional view showing essential parts of the embodiment, a horizontal cross-sectional view of a downcomer pipe support section, and a horizontal cross-sectional view of a tube bundle structure. 1...Body, 2...Top flange, 3...Lid flange, 4...Nozzle, 5...Nozzle, 6...Nozzle, 7...Nozzle, 8...Annular header, 10...
Annular header, 11... Upper connecting pipe, 12... Straight pipe (descending pipe), 13... Outer cylinder (shroud), 1
4...tube group support plate, 15...inner cylinder, 16...hole,
17... Straight pipe support, 18... Lower connecting pipe, 1
9... Heat exchanger tube, 23... Support ring, 24... Omega-shaped support fitting, 25... Radial key,
26...Keyway metal fitting, 27...Bolt.

Claims (1)

[Scope of utility model registration request] In a heat exchanger in which a straight pipe portion of a heat transfer tube is disposed outside a cylindrical shroud to extend in the axial direction thereof, a support ring is provided outside the shroud, and the straight pipe portion of the heat transfer tube is fixed to this; A heat exchanger characterized in that the cylindrical shroud and the support ring are assembled so as to be movable relative to each other in the axial direction of the cylindrical shroud by a radial key structure.