JP3764552B2 - Plate fin heat exchanger - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plate fin type heat exchanger that exchanges heat between fluids having a large temperature difference between a high temperature side fluid and a low temperature side fluid, such as atmospheric high pressure combustion gas and pressurized air or fluid.
[0002]
[Prior art]
3 and 4 show the structure of a conventional plate fin heat exchanger. In the plate fin heat exchanger shown in FIG. 3, the high temperature side fluid 20 is supplied from the inlet duct 40 and discharged from the outlet duct 41. On the other hand, the low temperature side fluid 30 flows in from the inlet nozzle 50 and flows out from the outlet nozzle 51. The inlet duct 40, the outlet duct 41, the inlet nozzle 50, and the outlet nozzle 51 are fixed to the outside of the heat transfer element by welding.
[0003]
On the other hand, the heat transfer element portion is composed of a plate (partition plate) 10, fins 11, and side plates 12 as shown in an enlarged end portion in FIG. 4, and has a structure in which the plate 10 and the fins 11 are laminated. Yes. The high temperature side fluid 20 and the low temperature side fluid 30 flow through the flow path formed between the stacked plates 10 step by step, and heat exchange is performed via the plates 10 and the fins 11.
[0004]
The fins 11 sandwiched between the plates 10 are fixed to the plate 10 with brazing, and the flow path through which the high temperature side fluid 20 and the low temperature side fluid 30 are flowed is formed by welding the plate 10 and the side plate 12. It has an integrated structure that does not mix each fluid.
[0005]
[Problems to be solved by the invention]
In the conventional technique, in order to prevent the high temperature side fluid 20 and the low temperature side fluid 30 from flowing out to the outside air, the plates and the side plates constituting the high temperature side flow channel and the low temperature side flow channel are all welded. Further, since the thermal expansion difference and thermal stress caused by the temperature distribution due to the flow rate imbalance between the high temperature side fluid 20 and the low temperature side fluid 30 cannot be relieved, problems such as cracks occur when the operation time becomes long.
[0006]
In addition, although the heat transfer element is heated by the high temperature side fluid at the time of start-up, the inlet / outlet nozzles 50 and 51 for the low temperature side fluid are not heated.
[0007]
The present invention provides a plate fin type heat exchanger in which plates and fins are alternately stacked and low temperature side fluid passages and high temperature side fluid passages are alternately formed between the plates to absorb a difference in thermal expansion, It is an object of the present invention to provide a configuration that can prevent generation of stress and generation of cracks.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problem in a plate fin type heat exchanger in which plates and fins are alternately stacked and low temperature side fluid passages and high temperature side fluid passages are alternately formed between the plates, Of the side plates arranged in the section, the side plate arranged between the plates constituting the low temperature side fluid passage is sealed with the same plate, but the side plate arranged between the plates constituting the high temperature side fluid passage is the same. A structure in which the plate is merely fixed without being welded or the like is used , and a heater for heating the inlet / outlet pipe base is installed at the inlet / outlet base of the low-temperature side fluid.
In the plate fin type heat exchanger according to the present invention, the side plate disposed between the plates constituting the high temperature side fluid flow path is not fixed by welding or the like, but is simply in contact with the plate, thereby depending on the temperature distribution. The difference in thermal elongation can be absorbed, and the generation of cracks due to thermal stress can be prevented.
[0010]
In the plate fin type heat exchanger according to the present invention, it is preferable to install a cylinder on the outer peripheral portion of the heat transfer element so as to prevent the high temperature side fluid or the low temperature side fluid from leaking to the outside air.
[0011]
In the plate fin heat exchanger of the present invention, a heater is installed at the base of the nozzle attached to the heat transfer section in order to reduce the temperature difference at the start of the heat exchanger in the inlet / outlet nozzle of the low temperature side fluid. It shall be the structure of heating the inlet and outlet pipe stand mounting part of the cold side fluid heater according to the flow rate of the high-temperature side fluid and the low temperature side fluid.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a plate fin heat exchanger according to the present invention will be described in detail based on the embodiment shown in FIGS. In the following embodiments, the same reference numerals are given to the same components as those of the conventional apparatus shown in FIGS. 3 and 4 for the sake of simplicity.
[0013]
In the plate fin heat exchanger shown in FIG. 1, the high temperature side fluid 20 is supplied from the inlet duct 40 and discharged from the outlet duct 41. The low temperature side fluid 30 flows in from the inlet nozzle 50 and flows out from the outlet nozzle 51. The inlet duct 40, the outlet duct 41, the inlet nozzle 50, and the outlet nozzle 51 are fixed to the outside of the heat transfer element by welding.
[0014]
On the other hand, as shown in FIG. 2, the heat transfer element portion is composed of a plate 10, fins 11, and side plates 12, and has a structure in which the plate 10 and the fins 11 are laminated. The high temperature side fluid 20 and the low temperature side fluid 30 flow through the flow path formed between the plates by laminating the plates 10, and are heat-exchanged via the plates 10 and the fins 11. The fins 11 are fixed to the partition plate 10 with brazing.
The above structure is the same as that of the plate fin type heat exchanger shown in FIG.
[0015]
However, the mounting structure between each plate 10 and the side plate 12 is different as follows.
That is, in the plate fin type heat exchanger according to the present embodiment, the side plate 12 of the low temperature side fluid 30 is welded to the plate 10 and the low temperature side fluid 30 is not mixed with the high temperature side fluid 20. On the other hand, the side plate 12 of the high temperature side fluid 20 is not welded to the plate 10 constituting the low temperature side fluid 30, and the fins 11 are only fixed by brazing.
[0016]
Therefore, in the plate fin type heat exchanger of the present embodiment, the low temperature side flow path and the high temperature side flow path are not fixed as a whole, and can absorb the difference in thermal elongation and relieve the thermal stress. Further, the fins 11 and the side plates 12 forming the flow path of the high temperature side fluid 20 have an effect as positioning for forming the flow path.
[0017]
In order to prevent the high temperature side fluid 20 from flowing out to the outside air, a body 60 is disposed on the outer periphery of the heat transfer element. Further, a heater 70 is provided at the attachment portion between the inlet nozzle 50 and the outlet nozzle 51 of the low temperature side fluid 30, and the temperature difference between the heat transfer element and the nozzle at the time of activation is arranged. It can be mitigated by a heater, and crack generation at the nozzle mounting portion can be prevented.
[0018]
However, this heater is used only at the time of start-up, and it is not necessary to use it during steady operation when the temperature reaches a high temperature.
[0019]
【The invention's effect】
As described above, in the high-temperature plate fin heat exchanger according to the present invention, among the side plates at the end of the plate, the side plate disposed between the plates constituting the low-temperature side fluid passage is sealed with the plate, and the high-temperature side fluid is fixed. Since the side plate arranged between the plates constituting the passage is configured to be in contact with the plate without being fixed by welding or the like, the high temperature side fluid passage and the low temperature side fluid passage are not fixed, and the low temperature Since the heater that heats the inlet / outlet pipe base is installed at the inlet / outlet pipe base of the side fluid, cracks due to generation of thermal stress can be prevented.
[Brief description of the drawings]
FIG. 1 is a structural diagram of a plate fin heat exchanger according to an embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view showing a mounting state between a plate and a side plate in the plate fin heat exchanger of FIG.
FIG. 3 is a structural diagram of a conventional plate fin heat exchanger.
4 is an enlarged cross-sectional view showing a mounting state between a plate and a side plate in the plate fin heat exchanger of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Plate 11 Fin 12 Side plate 20 High temperature side fluid 30 Low temperature side fluid 40 Inlet duct 41 Outlet duct 50 Inlet nozzle stand 51 Outlet nozzle stand 60 Body 70 Heater

Claims (1)

In a plate fin heat exchanger in which plates and fins are alternately stacked and a low temperature side fluid passage and a high temperature side fluid passage are alternately formed between the plates, of the side plates disposed at the end of the plate The side plate disposed between the plates constituting the low temperature side fluid passage is sealed and fixed to the plate, and the side plate disposed between the plates constituting the high temperature side fluid passage is fixed to the plate by welding or the like. A plate fin type heat exchanger having a structure that is not in contact with each other , and a heater that heats the inlet / outlet pipe base at the base of the low-temperature side fluid .

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