JPH0645166Y2 - Plate fin type heat exchanger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an improvement of a plate fin type heat exchanger used for heat exchange of high temperature fluid such as high temperature combustion exhaust gas and steam.

[Conventional technology]

As shown in FIG. 5, a commonly used plate fin type heat exchanger has spacer bars on both sides of a space formed between two tube plates (plate-shaped partition walls) 1, 1.
Fluid passages formed by arranging 2, 2 and corrugated fins (wavy partition walls) 3 between the spacer bars 2, 2 are laminated at several heights and integrally brazed. In the heat exchanger shown in the figure, the corrugated fins 3 are assembled in such a manner that they are orthogonal to each other at each stage, and the high temperature fluid A and the low temperature fluid B are adjacent to each other on the side surfaces 4,
Is taken into the fluid passage from and is flowed in the directions orthogonal to each other as shown by the arrows to perform heat exchange. In addition to the above-mentioned cross-flow type, the plate fin type heat exchanger includes a counter-flow type assembled.

[Problems to be solved by the device]

The conventional plate fin type heat exchanger as shown in FIG. 5 is used for heat exchange of a high temperature fluid such as high temperature combustion exhaust gas or steam, and is used under severe conditions of start and stop. There is a problem that the left and right ends (enclosed by circles) of the tube plate 1 at each stage on the one side surface 4 which is the inflow port are deformed or damaged.

As shown in FIG. 6, when the high temperature fluid A flows, the portions except the left and right end portions of the tube plate 1 that are in contact with the corrugated fins 3 are rapidly heated, while the left and right end portions of the tube plate 1 are heated. Since the contacting spacer bar 2 has a large heat capacity and the temperature rise is delayed, an extreme temperature gradient occurs at both ends of the tube plate 1 as shown in FIG.
This is because a very large excessive thermal stress is generated at this boundary portion.

The present invention has been made to solve such a problem, and is a plate that does not deform or break due to thermal stress even when used for heat exchange of high temperature fluid such as high temperature combustion exhaust gas and steam. It is intended to provide a fin type heat exchanger.

[Means for Solving the Problems]

In order to achieve the above object, in the present invention, as shown in FIG. 1, spacer bars 2 and 2 are arranged at both ends of a space formed between the tube plates 1 and 1, and the spacer bars 2 and 2 are arranged between the spacer bars 2 and 2. In a plate fin type heat exchanger in which the fluid passages formed by arranging the heat transfer fins 3 are stacked in a plurality of stages and the high temperature fluid A and the low temperature fluid B are passed through the respective fluid passages in different stages to perform heat exchange, Header tank 6 provided at the inlet of high temperature fluid A
A baffle plate 7 having an opening 7a projecting from the inner surface thereof and having a shield portion capable of covering the spacer bars 2, 2 and the fluid passages in the vicinity thereof is arranged at least on both sides of the opening 7a.

[Action]

According to the above configuration, as shown in FIGS. 1 and 2, the high temperature fluid A flows into the fluid passage provided with the heat transfer fins 3 through the opening 7a in the central portion of the baffle plate 7. Therefore, the baffle plate 7 blocks the high temperature fluid A from flowing into the fluid passage near the spacer bar 2 only slightly. As a result, the temperature distribution in the width direction of the tube plate 1 is as shown in FIG.
The temperature gradient in the vicinity of the contact with the space server 2 is remarkably alleviated, and the generation of thermal stress is prevented.

〔Example〕

FIG. 1 is an example of a plate fin type heat exchanger embodying the present invention.

The heat exchanger body is made of all stainless steel, and spacer bars 2 and 2 are arranged on both sides of the space formed between the two tube plates 1 and 1, and the spacer bars 2 and 2 function as heat transfer fins. The fluid passages formed by arranging the corrugated fins 3 are laminated at several heights. The fluid passage in which the corrugated fins 3 are provided between the tube plate fins 1 and 1 is of a so-called cross flow type in which the flow directions are orthogonal to each other, and the high temperature fluid A and the low temperature fluid B are adjacent to each other on the side surface 4 , 5 enter the fluid passages in different steps, flow in the orthogonal direction as indicated by arrows, and heat is exchanged.

A funnel-shaped header tank 6 is fixed by welding to one side surface 4 which is an inlet of the high-temperature fluid A, and an inner peripheral surface thereof is frame-shaped so as to cover the peripheral portion of the one side surface 4. The baffle plate 7 is fixed by brazing. The baffle plate 7 in the illustrated example is a stainless steel plate, and a high temperature fluid A is provided at the center.
Has a rectangular opening 7a for taking in
It is located slightly away from.

The high temperature fluid A flowing into the header tank 6 is baffle 7
Through the central opening 7a, the fluid enters the fluid passage provided with the corrugated fins 3 from the one side surface 4. As a result, a large amount of the high temperature fluid A is prevented from flowing into the fluid passage near the spacer bar 2. A part of the high temperature fluid A bypasses the baffle plate 7 but flows into the fluid passage in the vicinity of the spacer bar 2 though a little. As a result, compared to the case where the fluid inflow near the spacer bar 2 is completely blocked,
Although the thermal durability is somewhat reduced, the reduction in heat transfer efficiency is suppressed to a minimum.

It is desirable that the position where the baffle plate 7 is arranged is set so that the distance from the one side surface 4 is 0 to L / 10, where L is the depth of the header tank 6. When the distance from the one side surface 4 to the baffle plate 7 exceeds L / 10, the high temperature fluid A that wraps around behind the baffle plate 7 increases, and the meaning of providing the baffle plate 7 becomes thin.

Similar header tanks are provided at the outlet of the high temperature fluid A, the inlet of the low temperature fluid B, and the inlet.
No baffle plate is built in those header tanks.

The shape of the opening 7a in the baffle plate 7 is not limited to a rectangular shape as shown in the figure, and for example, a regular quadrangle shown in FIG. 4 (a), an octagon shown in (b), a circle shown in (c), etc. But it's okay. Alternatively, as shown in (d), only the left and right ends of the corrugated fin 3 may be covered with plate-shaped baffles 7, 7. In any case, it is necessary to leave at least left and right sides of the opening 7a a shielding portion that can completely cover the spacer bar 2 and the fluid passage in the vicinity thereof.

[Effect of device]

As described above, the plate fin type heat exchanger of the present invention is provided with a baffle plate near the inlet of the high temperature fluid so that a large amount of the high temperature fluid does not flow into the fluid passage near the spacer bar. The plate does not generate a large temperature gradient near the spacer bar. Therefore, thermal stress does not occur, and it is possible to prevent accidents such as deformation and damage of the tube plate due to thermal stress. Further, since a small amount of high-temperature fluid can be made to flow into the fluid passage near the spacer bar while bypassing the baffle plate, it is also possible to minimize the decrease in heat transfer efficiency associated with the attachment of the baffle plate.

[Brief description of drawings]

FIG. 1 is a perspective view of a plate fin type heat exchanger of the present invention, FIG. 2 is a plan view of essential parts for explaining the flow of high temperature fluid in the plate fin type heat exchanger of the present invention, and FIG. 3 is a plate fin type of the present invention. Graph showing the temperature distribution in the width direction of the tube plate in the heat exchanger, FIG. 4 (a) (b) (c)
(D) is a front view showing another example of the baffle plate according to the present invention, FIG. 5 is a perspective view illustrating a conventional plate fin type heat exchanger, and FIG. 6 is a conventional plate fin type heat exchanger. FIG. 7 is a plan view of the main part for explaining the flow of the high temperature fluid, and FIG. 7 is a graph showing the temperature distribution in the width direction of the tube plate in the conventional plate fin type heat exchanger. 1: Tube plate, 2: Spacer bar, 3: Heat transfer fin, 4: One side (high temperature fluid inlet), 6: Header tank, 7: Baffle plate, 7a: Open hole.

Claims (1)

[Scope of utility model registration request] 1. Spacer bars (2) and (2) are arranged at both ends of a space formed between tube plates (1) and (1), and heat transfer fins (3) are provided between the spacer bars (2) and (2). )
In a plate fin type heat exchanger that performs heat exchange by stacking fluid passages formed by arranging a plurality of layers and passing the high temperature fluid A and the low temperature fluid B through the respective fluid passages in different stages. The header tank (6) provided at the inlet has an opening (7a) projecting from the inner surface of the header tank (6) and a spacer bar (2) at least on both sides of the opening (7a).
A plate fin type heat exchanger characterized in that a baffle plate (7) having a shielding portion capable of covering the fluid passage (2) and its vicinity is disposed.