JPH0729412Y2 - Plate fin type heat exchanger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to an improvement of a plate fin type heat exchanger for recovering exhaust heat of extremely high temperature, in which a fin at a specific position in a high temperature side fluid passage is cut off. The present invention relates to a plate fin type heat exchanger in which thermal stress generated in a tube plate is relaxed.

2. Description of the Related Art A plate fin type heat exchanger has a large heat transfer area per unit volume and a high heat transfer coefficient, and thus has an advantage that it can be easily made compact as compared with other types, particularly a tube type heat exchanger.

In addition, the plate fin type heat exchanger has a wide selection range in design, such as the fin pitch, fin height, and fin shape that are suitable for the properties of the fluid flowing down each passage and the purpose, and so on. Is also used in a wide variety of applications because it can be arbitrarily selected and can be efficiently designed.

Problems to be Solved by the Invention As shown in FIG. 3, fins (2) are interposed between tube plates (1) and (1) to close a required portion with a spacer bar (3) to form a fluid passage in a required direction. In a plate fin type heat exchanger in which a required number of these fluid passages are stacked and the side plate (4) is placed in the outermost layer and integrated by brazing, a high temperature side fluid passage and a low temperature side fluid passage in countercurrent arrangement are provided. No heat exchange between gas / gas, liquid / gas, liquid /
When used as a heat exchanger for recovering waste heat of liquids, for example,
If the passage on the side plate (4) side of the outermost layer is the high temperature side fluid passage and the low temperature side fluid passage is arranged via the tube plate (1), the high temperature side fluid temperature is particularly 350 to 800 ° C
In the case of high temperature, if there is a temperature difference between the side plate (4) and the tube plate (1), a difference in thermal expansion occurs, and as shown in FIG. It has been found that the side plate (4) at a relatively low temperature works to pull back the elongation and generates a high stress near the spacer bar (3) of the tube plate (1) between both passages.

Further, as shown in FIG. 2b, the fin (2) of the high temperature side fluid passage (10) and the spacer bar (3) of the low temperature side fluid passage (11).
The elongation in the y direction also differs depending on the temperature difference between the two, and a high stress is generated near the spacer bar (3) of the tube plate (2) between both passages.

In view of the above-mentioned problems of the plate fin type heat exchanger that recovers exhaust heat of extremely high temperature, the present invention is a plate fin type having a configuration capable of relieving high stress generated in a tube plate due to a large temperature difference between fluid passages. The purpose is to provide a heat exchanger.

Means for Solving the Problems The present invention is directed to forming fins between tube plates to form fluid passages in a desired direction with a spacer bar and stacking the fluid passages so that heat is generated between adjacent high temperature fluid passages and low temperature fluid passages. In the plate fin type heat exchanger to be replaced, the fins in the vicinity of the spacer bars at both ends in the passage width direction of the fin within the range of 100 mm from the fluid inlet end of the high temperature side fluid passage to the outlet side are cut off, or In the plate fin type heat exchanger, the fins are cut off over the entire width in the passage width direction.

Function The present invention is characterized in that the fins at the fluid inlet of the high temperature side fluid passage of the plate fin type heat exchanger are cut off near the spacer bars at both ends in the passage width direction or over the entire width, and the fins near the spacer bars are eliminated. As a result, or because there is no fin near the inlet, the deformation of the tube plate becomes gentle and the stress is relieved.

However, if the fins are cut off over the entire length of the passage, performance deterioration and strength insufficiency will occur, and in order to obtain the desired effect, within 100 mm from the fluid inlet end of the high temperature side fluid passage to the outlet side. It is necessary to cut off a certain fin, and it may be appropriately selected according to the size of the heat exchanger core and the fluid temperature.

Further, the effect of cutting off the fins is such that the higher the temperature of the fluid on the high temperature side, the more effective is the effect of relieving stress even with a very small amount of cutting. It is most suitable for heat exchangers for gas turbine regenerators and heat exchangers for exhaust heat recovery of high-temperature exhaust gas.

The present invention can be applied to any plate fin type heat exchanger in any configuration such as plate material, fin shape difference, number of stacked layers, parallel flow arrangement, cross flow arrangement, countercurrent arrangement, and the like. Produces the effect of.

Example Configuration 1 The plate fin type heat exchanger shown in FIG. 1a is for recovering heat from a fluid at a high temperature of 600 ° C., and includes a tube plate (1), fins (2) and spacer bars (3). ,
Stainless steel (SUS304) on all side plates (4)
Is used to form a three-layer structure (120 mm × 120 mm × length 200 mm).

To be more specific, two side plates (4) and (2) are placed between the two side plates.
A tube plate (1) (1) is arranged, spacer bars (3) are provided at both ends in the longitudinal direction between the plates, and fins (2) required between the spacer bars (3) (3) of each layer are provided.
, And these are integrated by brazing to stack the three fluid passages to form a plate fin type heat exchanger.

In the middle of the three fluid passages, a fin (2) with no chipping is arranged over the entire length and width of the low temperature side fluid passageway (11), and two high temperature side fluid passageways (10) adjacent to the fins (2) are A fin (2) having a cutout portion (2a) formed by cutting out a part of the fin near the spacer bars (3) at both ends in the passage width direction is arranged over 25 mm from the fluid inlet to the outlet side.

By providing the cutout portion (2a) and eliminating the fin (2) near the spacer bar (3), as shown in FIG. 2a,
The deformation (indicated by the broken line) that occurred with high stress near the spacer bar (3) of the tube plate (1) between the two passages becomes gentle as shown by the solid line, and the thermal stress is half that of the conventional one.
Is alleviated.

Configuration 2 The plate fin type heat exchanger shown in FIG. 1b has the same configuration as that of FIG. 1a, and the fin (2) arranged in the high temperature side fluid passageway (10) has a diameter of 15 mm from the fluid inlet to the outlet side. A finless portion (2b) is provided over the entire width of the passage.

As shown in FIG. 2b, the finless portion (2b) is provided near the inlet of the high temperature side fluid passageway (10), so that a high stress is generated near the spacer bar (3) of the tube plate (1) between the passageways. The deformation that has occurred (shown by the broken line) becomes gentle as shown by the solid line, and the stress is relieved.

Advantageous Effect of the Invention The present invention removes the fins in the vicinity of the spacer bars at both ends in the passage width direction at a predetermined position from the fluid inlet of the high temperature side fluid passage, or by cutting the fins over the entire width in the passage width direction. As shown in Figures a and b, deformation in the x-direction or the y-direction that was generated with high stress near the spacer bar of the tube plate (1) between the high temperature side fluid passage and the low temperature side fluid passage passage (shown by the broken line). Has the effect of easing the stress and relaxing the stress.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A and 1B are perspective explanatory views showing an example of a plate fin type heat exchanger according to the present invention. 2a and 2b are explanatory views of a tube plate showing a stress generation state of the plate fin type heat exchanger according to the present invention. FIG. 3 is a perspective explanatory view showing an example of a conventional plate fin type heat exchanger. FIGS. 4a and 4b are explanatory views of a conventional plate fin type heat exchanger showing stress generation. 1 ... Tube plate, 2 ... Fins, 2a ... Excision part, 2b ...
Finless portion, 3 ... Spacer bar, 4 ... Side plate, 10 ... High temperature side fluid passage, 11 ... Low temperature side fluid passage.

Claims (2)

[Scope of utility model registration request] 1. A plate fin type heat exchanger in which fins are interposed between tube plates to form fluid passages in a desired direction by spacer bars, and the fluid passages are stacked and heat is exchanged between adjacent high temperature side fluid passages and low temperature side fluid passages. In the heat exchanger, a plate fin type heat exchange characterized by the fact that fins in the vicinity of spacer bars at both ends of the fin in the passage width direction within the range of 100 mm from the fluid inlet end of the high temperature side fluid passage to the outlet side are cut off. vessel. 2. The plate fin type heat exchange according to claim 1, wherein the fins within a range of 100 mm from the fluid inlet end of the high temperature side fluid passage to the outlet side are removed over the entire width in the passage width direction. vessel.