JPH07167579A - Plate fin type heat exchanger - Google Patents

Abstract

PURPOSE:To prevent fins in the core parts from being damaged mainly due to the accumulation of fatigue by installing reinforced fins or members whose rigidity in the height direction is higher than that of other fins or members. CONSTITUTION:Reinforced fins 5 or a reinforcing member, whose rigidity in their height direction is higher than the others, is installed in a fluid passage in such a fashion that fins 2 may be protected from being damaged by compression force or tensile force. For example, the reinforced fins 5 or a holed reinforcing member are installed for a specified length over the whole width of the inlet of the fluid passage of a high or low temperature fluid, or the reinforced fins 5 are installed only to the central part of the inlet where they are subjected to the highest or lowest temperature. This construction makes it possible to protect the core members of a heat exchanger from damages or deformations to be produced by a thermal stress and heat exchange for a long time in a stabilized manner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a plate fin type heat exchanger, particularly when it is repeatedly used at a high temperature for a long time in a chemical plant or a fuel cell plant, or in a low temperature industrial plant. The present invention relates to a plate fin type heat exchanger which prevents the core component member of the plate fin type heat exchanger from being deformed or damaged due to thermal stress when it is repeatedly used at a low temperature for a long time.

[0002]

2. Description of the Related Art In a chemical plant, a fuel cell power plant, etc., the temperature of a high temperature fluid is 500 ° C. or more, and a heat-resistant alloy plate fin type heat exchanger made of stainless steel or the like used in the plant is fully used. The number of times of starting and stopping during the period is thousands, and the time of exposure to high temperature reaches tens of thousands to hundreds of thousands of hours. In addition, the plate fin type heat exchanger made of aluminum used in a low temperature industrial plant where the temperature of the low temperature fluid is −160 ° C. or lower reaches a few thousand times.

As shown in FIG. 5, the heat exchange core portion which is the heart of this heat exchanger comprises a plate-shaped tube plate 1 for partitioning the low temperature fluid passage and the high temperature fluid passage, and a rectangular plate for promoting heat transfer. The fins 2 are alternately laminated, and a spacer bar 3 for keeping a space between the tube plates 1 and 1 and sealing a flow path is arranged on both side surfaces. There are various configurations depending on how the low-temperature fluid and the high-temperature fluid flow in the core portion. A of FIG. 5 is a cross-flow type in which A and C are cross-flow, and B of FIG. . Further, a header tank, which is thicker than the tube plate 1 and has high rigidity, is arranged at the required end surface of the core portion as the inlet and outlet of each fluid.

In the plate fin type heat exchanger, various components such as a tube plate, heat transfer fins and spacer bars are layered and assembled with a brazing material appropriately and brazed at a high temperature in a vacuum heating furnace. After that, the header tank is manufactured by being integrated with the laminated assembly (core) by welding. Since the plate fin type heat exchanger is designed to perform heat exchange through a tube plate that divides the flow path between the low temperature fluid and the high temperature fluid, it can be used as a shell-and-tube heat exchanger with the same heat exchange capacity. In comparison, it has a feature that it can be downsized because it has a large heat transfer area for its size.

[0005]

In a heat exchanger handling a high-temperature fluid of 500 ° C. or higher, the temperature near the inlet of the high-temperature fluid passage of the heat exchanger is higher than that of the central portion of the side surface of the heat exchanger shown in FIG. 6A. The temperature at the width end is low, and the temperature difference between the central portion and both end portions occurs even in a steady state during operation, but a transiently larger temperature difference occurs when the temperature rises at the time of starting. Due to this temperature difference, as schematically shown in FIG. 6B, a force is applied that crushes the fin having the weakest rigidity in the y direction. When this force exceeds the buckling load of the fin, C in FIG. The fin 2 is deformed into a dogleg shape as shown in FIG. Further, a force for peeling the fin acts during the operation at low temperature and at the time of temperature decrease.

Therefore, in the conventional core structure of the plate fin type heat exchanger, the fin portion is repeatedly compressed or buckled and pulled by repeating the heating and cooling of the heat exchanger. There was a problem that damage due to fatigue was accumulated, and creep damage was added at high temperatures, and the damage to the fins of the core became large as the operation was continued for a long time, eventually causing cracks. The above-mentioned problem of the heat exchanger handling the high temperature fluid is the same in the heat exchanger handling the low temperature fluid of −160 ° C. or less, that is, whether the temperature is high or low at the low temperature inlet of the heat exchanger for low temperature, that is, whether it is compression or tension. On the contrary, there was a problem that similar fatigue damages were accumulated to cause cracks.

The present invention relates to a stainless steel plate fin type heat exchanger in a chemical plant, a fuel cell power generation plant or the like, or an aluminum plate fin type heat exchanger in a low temperature industrial plant, etc. An object of the present invention is to provide a plate fin type heat exchanger having a structure capable of preventing damage to the fins of the core part, which is mainly caused by accumulation of fatigue generated in the fins, by repeating temperature increase and decrease.

[0008]

According to the present invention, in a plate fin type heat exchanger, a reinforcing fin or a reinforcing member having a higher rigidity in the fin height direction than other fins is provided in a part of the fin in the fluid passage. Is a plate fin type heat exchanger. Further, according to the present invention, in the above structure, the reinforcing fins are thick-walled fins, the reinforcing fins are high-density fins, and the helix bone type fins are arranged in the plain type fins to form the reinforcing fins. In addition, a plate fin type heat exchanger characterized in that a louver type fin is arranged in a serrate type fin to form a reinforcing fin, and the reinforcing member is a perforated mold member or a spacer bar. suggest.

Further, the present invention is the plate fin type heat exchanger, wherein the fins are arranged so as to protrude from the end face of the core opening in the header tank.

[0010]

The operation of the plate fin type heat exchanger according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a top view of a fluid passage showing the arrangement positions of the reinforcing fins of the plate fin type heat exchanger according to the present invention. FIG. 2 is an explanatory view showing a reinforcing fin and a reinforcing member, A and B are end surface explanatory views, and C and
D, E, and F are perspective explanatory views. 3A and 3B are explanatory views showing the structure of another plate fin type heat exchanger according to the present invention, in which A is a perspective explanatory view and B is a front explanatory view. 4A and 4B are perspective explanatory views schematically showing deformation due to stress applied to the fins of the plate fin type heat exchanger, where A is the conventional case and B is the case of the present invention. The present invention is characterized in that a reinforcing fin or a reinforcing member having higher rigidity in the fin height direction than the other is arranged in the fluid passage so that the fin is not damaged by compression or tension. Alternatively, if the reinforcing member is adopted on the entire surface of the passage, the required specifications of performance or pressure loss cannot be satisfied, so that the arrangement position is limited to a part of the passage. Furthermore, excessive reinforcement may increase the stress generated in other members such as the tube plate and damage them.Therefore, the specifications and arrangement range of the reinforcement fins or reinforcement members should be calculated and calculated. Need to be selected appropriately.

As an example, as shown in FIG. 1A, the reinforcing fins 5 or perforated reinforcing members are arranged over the entire width of the inlet of the fluid passage 4 for the high temperature fluid or the low temperature fluid, or the reinforcing member for perforation is arranged as shown in B of FIG. As shown in FIG. 5, the reinforcing fins 5 are provided at both the inlet and the outlet of the fluid passage 4 over the entire width and required length.
Can be placed. Further, the reinforcing fins 5 can be arranged only in the central portion where the temperature becomes highest or lowest at the inlet of the fluid passage 4, and as shown in C of FIG. As described above, the reinforcing fins 5 can be arranged at the central portions of both the inlet and the outlet of the fluid passage 4, and further at the central portion of the required width of the fluid passage 4 and over the entire passage length as shown in E.
The positions of the reinforcing fins are appropriately selected according to the application of the heat exchanger and the fluid temperature, but as shown in F of FIG. 1, two or more reinforcing fins are provided at predetermined positions at the inlet of the fluid passage 4. The fins 5 may be arranged, and the reinforcing fins 5 may be arranged at both the inlet and the outlet of the fluid passage 4 as shown in the same G, or over the entire length of the fluid passage 4 as shown in the same H, if necessary. You can

Various kinds of reinforcing fins or reinforcing members can be adopted. For example, as shown in FIG. 2A, by making the reinforcing fin 10 thicker than the plate thickness of a normal fin, one sheet is used. It is possible to improve the load that can be carried by the above, and as shown in B, by disposing the reinforcing fins 11 having a higher density than the normal fins, the load per sheet in the reinforcing fin portion can be reduced. Further, as shown in FIG. 2C, a herringbone type undulated in the flow direction is arranged as the reinforcing fin 12 in a normal plane type fin, and it becomes strong against buckling,
Further, when the louver fins are arranged as the reinforcing fins 13 in the ordinary serrate fins as shown in D, it becomes strong against buckling. Further, as shown in E of FIG. 2, as the support body having higher rigidity than the fin, by using the mold member 14 having the same fin height as that in which a plurality of passage holes are arranged, high rigidity against compression or the like is exhibited. Further, by using the spacer bar 15 shown in the same F as necessary, the same operational effect can be obtained.

In the plate fin type heat exchanger, when a high temperature fluid flows into the high temperature fluid passage at the time of start-up, A in FIG.
As shown in Fig. 6, when explained with a single fin pitch, in the conventional configuration, the fin is deformed by the force of crushing up and down, and in particular, the fin tip, which is the fluid inlet, is the closest to the fluid temperature and its expansion is large, so the deformation is also large. . Therefore, as shown in FIGS. 3A and 3B, by disposing the fins 2 so as to project from the end face of the core opening in the inlet header tank of the high temperature fluid passage, the fin tips become particularly hot as shown in FIG. 4B. Although it is a large stretched area, there is no member to press it down, so the part that pops out when the force to crush the fin 2 is applied can also resist as a pressure receiving area, and it is a plate fin type heat exchange that is strong against buckling. Become a vessel.

[0014]

【Example】

Example 1 As a stainless steel plate fin type heat exchanger used in a fuel cell power plant, plain fins are used as passage fins, and thick fins shown in FIG. 2A are used as reinforcing fins. As shown in 1B, the plate fin type heat exchanger according to the present invention was prepared by arranging the hot fluid passage over the entire width of both the inlet and the outlet. However, simply increasing the thickness of the reinforcing fins increases the fluid resistance and cannot satisfy the pressure loss of the specifications. Therefore, it is necessary to make the fin pitch a little rough, and if the fin pitch is too rough, the reinforcing effect will be lost. Therefore, the optimum plate thickness and fin pitch that satisfy both the reinforcing effect and the predetermined pressure loss were examined by analysis and testing. Comparing the lives of the conventional heat exchanger using the serrated fins for the passage fins and the heat exchanger of the present invention in which the reinforcing fins are arranged, the heat exchanger of the present invention has been improved ten times as long as the conventional one.

Example 2 In a stainless steel plate fin type heat exchanger used in a fuel cell plant and using plain fins as passage fins, the fins are protruded by 5 mm from the open end face of the core portion in the high temperature fluid inlet header tank. A plate fin type heat exchanger according to the invention was created. The life of the heat exchanger of the present invention is twice as long as that of the conventional heat exchanger in which the fins do not protrude from the open end face of the core portion.

[0016]

According to the present invention, in the plate fin type heat exchanger, a reinforcing fin or a reinforcing member having high rigidity in the fin height direction is used for a part of the passage, or a fin of 2 to 20 mm from the opening end face of the core portion is used. By adopting a configuration such as popping out, heat is generated even when repeatedly used at high temperature in a chemical plant or fuel cell plant for a long time, or when repeatedly used at a low temperature for a long time such as a low temperature industrial plant. The core component member of the exchanger is less likely to be deformed or damaged due to thermal stress, and stable heat exchange is possible for a long period of time.

[Brief description of drawings]

1A to 1H are plan explanatory views of fluid passages showing various examples of arrangement positions of reinforcing fins of a plate fin type heat exchanger according to the present invention.

FIG. 2 is an explanatory view showing a reinforcing fin and a reinforcing member,
A and B are end face explanatory views, and C, D, E, and F are perspective explanatory views.

3A and 3B are explanatory views showing the configuration of another plate fin type heat exchanger according to the present invention, in which A is a perspective explanatory view and B is a front explanatory view.

FIG. 4 is a perspective explanatory view schematically showing deformation due to stress applied to the fins of the plate fin type heat exchanger according to the present invention, where A is the conventional case and B is the case of the present invention.

5A and 5B are explanatory views showing a configuration of a conventional plate fin type heat exchanger, where A is an exploded perspective view and B is a perspective view showing a fluid flow.

FIG. 6 is an explanatory view showing a state of a fluid passage of a conventional plate fin type heat exchanger, where A is a room temperature, B is a high temperature or a temperature rise, and C is a modified example of the fin.

[Explanation of symbols]

 1 Tube plate 2 Fins 3 Spacer 4 Fluid passage 5 Reinforcing fins 10, 11, 12, 13 Reinforcing fins 14 Model material 15 Spacer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yu Usami 2-30 Kanda Jinbocho, Chiyoda-ku, Tokyo Tokyo Electric Power Co., Inc. Development Laboratory (72) Inventor Shohei Matsuda 2-Suehiro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa 4 In Toshiba Keihin Office (72) Inventor Takao Inukai 2-4 Suehiro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa Incorporated Toshiba Keihin Office (72) Inventor Katsuo Iwata 1-10 Fuso-cho, Amagasaki-shi, Hyogo Sumitomo Precision Industries Ltd. (72) Inventor Norihiro Hisada 1-10 Fusocho, Amagasaki City, Hyogo Prefecture Sumitomo Precision Industries Ltd.

Claims (7)

[Claims] 1. A plate fin type heat exchanger characterized in that a reinforcing fin or a reinforcing member having higher rigidity in the fin height direction than that of the other fins is provided in a part of the fins in the fluid passage. Exchanger. 2. The plate fin type heat exchanger according to claim 1, wherein the reinforcing fins are thick wall fins. 3. The plate fin type heat exchanger according to claim 1, wherein the reinforcing fins are high density fins. 4. The plate fin type heat exchanger according to claim 1, wherein a helix bone type fin is provided in the plane type fin to form a reinforcing fin. 5. The plate fin type heat exchanger according to claim 1, wherein louver type fins are provided in the serrate type fins to form reinforcing fins. 6. The plate fin type heat exchanger according to claim 1, wherein the reinforcing member is a perforated mold member or a spacer bar. 7. A plate fin type heat exchanger, wherein fins are provided so as to project from an end face of the core opening in the header tank.