JPS6330079Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a heat exchanger for exchanging heat from a primary (high temperature) side heat medium to a secondary (low temperature) side heat medium. The present invention relates to a heat exchanger that improves safety by preventing low-temperature side members from being directly exposed to high temperatures due to the primary medium that does not undergo heat exchange in the event of an accident.

In recent years, heat generated in high-temperature heating furnaces (for example, nuclear reactors) is extracted using a heat medium such as sodium, and this is exchanged with a secondary heat medium in an intermediate heat exchanger, and the heat obtained here is used to generate electricity, etc. It is considered to do so.

An example of the structure of a heat exchanger used in this high-temperature heating furnace will be explained with reference to FIG. A primary heating medium inlet 2 is formed for introducing a high temperature primary heating medium obtained from a heat exchanger (not shown) into the container 1. The high-temperature primary heat medium introduced into the container 1 from the primary heat medium inlet 2 rises between branch pipes 3 in the container 1 in which a large number of branch pipes 3 serving as heat transfer tubes are provided. The primary heat medium that has reached the top is the inner wall 1a of the container.
descending through the flow path 5 formed between the and the partition wall 4,
Eventually, the heat medium is discharged from the primary heat medium outlet 6 formed in the lower side of the container 1 and transferred to the high temperature heating furnace again.

On the other hand, the branch pipe 3 is spirally formed around a main pipe 7 provided along the axial direction of the central part of the container 1, and one end thereof is connected to a secondary heat transfer medium formed at the uppermost end of the container 1. It is attached to the inlet 8 by a header, and the other end is gathered by the header and connected to the main pipe 7.
The low-temperature secondary heating medium introduced from the secondary heating medium inlet 8 flows down inside the spirally formed branch pipe 3 and flows into the primary heating medium. The secondary heat medium heated by the heat exchange flows into the main pipe 7, rises therein, and reaches the upper end of the main pipe 7, that is, the container 1.
The heat medium is transferred to other devices from a secondary heat medium discharge port 9 formed at the top end of the heat medium. In the figure, reference numeral 10 indicates a heat insulating material provided around the outer periphery of the container 1, and reference numeral 4a indicates an internal heat insulating material provided inside the partition wall 4.

However, in the configuration described above,
In the unlikely event that the secondary side heat medium circulation pump (not shown) stops or an accident occurs such as damage to a part of the secondary side piping, the primary side heat medium circulation pump (not shown) However, as mentioned above, a very high-temperature heat medium from the high-temperature heating furnace is introduced into the heat exchanger, and after the primary side circulation pump is stopped, this high-temperature heat medium undergoes natural convection. As it rises inside the container, the container top 11 is directly exposed to the primary heat medium which remains at a high temperature and is not subjected to heat exchange. In addition, the top part 11 of the container has a complicated structure, such as the formation of a secondary heat medium inlet 8 and an outlet 9, and is a stress concentration area. Abnormal stress occurs,
As a result, there is a risk that the life of the container will be shortened and the top 11 of the container will crack or even break.

The present invention was developed in view of these circumstances, and its purpose is to prevent the top of the container from undergoing heat exchange and to recover the heat from the primary side, which remains at a high temperature, in the event that an accident such as a secondary circulation pump stoppage occurs. The purpose is to alleviate the risk of abnormal stresses occurring due to particularly local exposure to the medium.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 2 shows an example of the present invention to which the invention shown in FIG. 1 is applied. In the figure, parts given the same reference numerals as in FIG. 1 indicate the same members. In a heat exchanger configured similarly to that shown in FIG. 1, a reflector plate 13 is fixed to the main pipe 7 and is provided to form a protective space 12 directly below the top portion 11 of the container. The reflecting plate 13 has an upwardly protruding curved shape that is effective in reflecting the high temperature primary heat medium rising from below and preventing it from directly hitting the top of the container, and has a curved shape that is convex upward and is effective for reflecting the high temperature primary heat medium rising from below and preventing it from directly hitting the top of the container. 1
A gap 14 is formed between the inner wall 1a and the inner wall 1a.

In the above configuration, during normal operation, the operation is exactly the same as in the case of FIG.

On the other hand, if an accident occurs and the introduction of the secondary heat medium is stopped, the high-temperature heat medium from the primary heat medium inlet 2 rises inside the container 1 without undergoing heat exchange. However, the reflector plate 1 according to the present invention provided on the upper part
The effect of 3 prevents the upward flow of high-temperature heat medium from directly colliding with the top of the container, so in the event of an accident like the one described above, the generation of abnormal thermal stress due to a localized temperature rise at the top of the container is prevented or suppressed. can be done. In addition, the reflective plate 13 and the gap 14
The heat is conducted upwards through the protected space 12.
This prevents the top of the container from rapidly rising in temperature locally.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be applied to other heat exchangers having similar problems, and that the shape and structure of the reflector plate can be modified in various ways. Of course, various changes may be made without departing from the spirit of the invention.

According to the heat exchanger of the present invention described above, since it is equipped with a reflector plate, in the event that an accident such as a stoppage of the circulation pump on the secondary side occurs, the top of the container will not be able to exchange heat with the high temperature primary heat medium. By preventing direct exposure to heat, the generation of abnormal stress can be suppressed, and the safety of the heat exchanger can be increased.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view showing a conventional heat exchanger;
The figure is a longitudinal sectional view showing an embodiment of the present invention. 1 is a container, 3 is a branch pipe (heat exchanger tube), 11 is the top of the container, 12 is a protected space, and 13 is a reflection plate.

Claims (1)

[Scope of utility model registration request] In a heat exchanger in which a secondary heat medium descends inside a heat transfer tube provided in a container, and a primary heat medium rises outside the heat transfer tube, a protective space is formed below the top of the container. A heat exchanger characterized by being provided with a reflective plate.