JPH03230096A - Plate fin type heat exchanger - Google Patents

Abstract

PURPOSE:To obtain sealability without complicating a welding work of a distance plate to a separator by welding a connecting part exposed out of the plate and the separator toward a laminating direction. CONSTITUTION:Three recesses 41 are electrically discharge-formed or formed by a grinder at both upper and lower side ends of a plate fin unit having distance plates 39 and separators 25 toward a laminating direction, connecting parts exposed out of the separators 25 and the plates 39 are welded by using the recesses 41 to form welded parts 43. In addition, the contact parts of the separators 25, the plate fins 23 and the plates 39 are brazed. The parts 43 are formed to improve rigidity of the unit side, and thermal deformation is suppressed to obtain sealability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) This invention relates to a plate-fin type heat exchanger used for improving cycle efficiency in a gas turbine system.

(Prior Art) Since the combustion gas discharged from the turbine has a high temperature, the cycle efficiency of the gas turbine is improved by using a heat exchanger to recover the heat and supplying it to the combustion air. Such heat exchangers, especially plate-fin type heat exchangers, use thin plates to form a flow path for the heat exchange fluid, and the heat exchange fluid performs a heat exchange action by passing through the flow path. , shown in FIGS. 9 and 10 (see Japanese Patent Laid-Open No. 63-58099). Plate fins 3, which are thin plates bent into a rectangular wave shape to form flow paths 1 for heat exchange fluid, are laminated in multiple layers with separators 5 in between. The separator 5 protrudes from the plate fins 3 at both end portions, and a long distance plate 7 is interposed between the separators 5 to form a plate fin unit 9. The plate fin unit 9 is held by upper and lower fixing plates 11.13, and bolts 15
and is fixed with a nut 17.

The upper and lower corners of the distance plate 7 are chamfered C, and using this chamfer C, when the plate fin unit 9 is fixed, the corners of the distance plate 7 and the ends of the separator 5 are connected. Fix by welding and welding part 1
At the same time, the separator 5 and the plate fins 3 and the distance plate 7 excluding the corner portions are brazed to form a portion 21. This prevents thermal distortion of the distance plate 7 and deterioration of sealing performance due to thermal distortion when used for a long time at a high temperature of about 800° C., for example.

(Problem to be solved by the invention) However, since such conventional plate-fin type heat exchangers have a common part welded along the entire length of the long distance plate, it is especially difficult to In the case of plate fin units, the welding length is long and workability is poor.
Further, if the thickness of the distance plate is as thin as 1 inch to several inches, welding work becomes difficult and miniaturization of the heat exchanger is hindered.

Therefore, an object of the heat exchanger of the present invention is to ensure sealing performance without complicating the welding work between the distance plate and the separator.

[Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention creates a heat exchange fluid flow path by alternately stacking wave-like plate fins and flat plate-like separators. In a plate fin type heat exchanger, in which distance plates are interposed at both ends of the plate fins to regulate the distance between the separators and the separators, the joints between the distance plates and the separators are exposed to the outside. are welded together in the stacking direction.

(Function) The joint portions of plate fins and separators that are alternately stacked and exposed to the outside are welded together in the stacking direction to ensure sealing performance. Welding between plate fins and separators is performed in the direction in which they are laminated, so there is no need to weld along the distance plate, so even if the plate fin unit is laminated in multiple layers, the welding length can be shortened. It is short, which improves workability, and even when the distance plate is one to several orders of magnitude thinner, welding work becomes easier.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 show a first embodiment of the invention. Plate fin 23 in which a thin plate is bent into a wave shape
The separators 25 and 25 are alternately stacked, and the air passages 27 and the combustion gas passages 29 are alternately arranged in the stacking direction. By passing through the combustion gas flow path 29, the plate fin 2
The combustion gas heating the plate fin unit 3 flows in from the gas outlet 31 at the right end of the plate fin unit, passes through the combustion gas passage 29, and flows out from the gas outlet 33 at the left end, as shown by arrow G. On the other hand, the air receiving heat from the heated plate fins 23 flows in through the air flow path 27 in the direction perpendicular to the inflow direction of the combustion gas as shown by arrow A, passes through the air flow path 27, and flows in the same direction as the inflow direction. The air flows out from the air outlet 37.

The separators 25 protrude from the plate fins 23 at both end portions, and a long distance plate 39 is interposed between the separators 25 at the protruding portions, thereby forming a plate fin unit. Like the conventional example, this plate fin unit is held by upper and lower fixing plates (not shown) and fixed with bolts and nuts.

Three recesses 41 are formed in the upper and lower end surfaces of the plate fin unit in FIG. 3, which is composed of the distance plate 39 and the separator 25, in the stacking direction (vertical direction in FIG. 2) by electric discharge machining or grinding. The separator 25 is formed by using the concave portion 41.
A welded portion 43 is formed by welding the externally exposed joint between the distance plate 39 and the distance plate 39 . In addition, the contact portions between the separator 25, the plate fins 23, and the distance plate 39 are brazed. By forming the welded portion 43, the rigidity of the side portion of the plate fin unit is improved, thermal deformation is suppressed, and sealing performance is ensured.

Since the welded portion 43 is formed in the stacking direction, there is no need to weld along the long distance plate 39.
Therefore, even if the plate fin unit is laminated in multiple layers, the welding length is short and workability is improved.
Even when the thickness of the distance plate 39 is one to several orders of magnitude thinner, welding work becomes easier and the heat exchanger can be made smaller.

FIG. 5 shows a second embodiment of the invention.

In this embodiment as well, plate fins 45 and separators 47 are alternately stacked in multiple layers, and air channels 49 and combustion gas channels 51 are alternately arranged in the stacking direction. Then, flat metal foils 55 are brazed to both sides of the plate fin unit, including the sides of the long distance plate 53 interposed between the separators 47 and the ends of the separators 47. An attached portion 57 is formed. Furthermore, the contact portions between the separator 47, the plate fins 45, and the distance plate 53 are formed by brazing into brazing portions 59 and 61, respectively.

By brazing the metal foil 55 to both side ends of the plate fin unit, the brazing will not occur due to thermal distortion.
Even if the airtightness of the heat exchanger decreases, sufficient sealing performance is ensured and the durability of the heat exchanger is improved.

FIG. 6 is a modification of FIG. 5, in which a wavy metal foil 63 is brazed in place of the flat metal foil, and a portion 65 is formed by brazing. It is assumed that openings 64 on the front and back sides of the paper surface of the wavy metal foil 63 in FIG. 6 are sealed by members not shown. Since the metal foil 63 is wavy, it can follow deformation such as thermal distortion of the distance plate 53, and the durability of the metal foil 63 is improved.

7 and 8 show a third embodiment of the invention. In this embodiment, a welded part 71 is formed by spot welding, beam welding, etc. at the joint part of the separator 67 and distance plate 69 exposed to the outside on the side of the air population 35 and air outlet 37 shown in FIG. be. Further, a brazing portion 73 is formed between the separator 67 and the distance plate 69.

Since the separator 67 and the distance plate 69 on the side of the air intake 35 are welded together, the separator 67 is prevented from turning over due to inflowing air and outflowing air entering between the separator 67 and the distance plate 69.

This suppresses increases in pressure loss on the air flow path side and variations in product performance.

[Effects of the Invention] As explained above, according to the present invention, the externally exposed joints of the plate fins and separators stacked alternately are welded together in the stacking direction.
In addition to ensuring sealing performance, the welding length can be shortened even if the plate fin unit is laminated in multiple layers, improving workability, and it can also be used when the distance plate is as thin as one to several fins. However, the welding work becomes easier,
It can contribute to the miniaturization of heat exchangers.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a plate fin unit showing a first embodiment of the invention, FIG. 2 is a side view of the same plate fin unit, FIG. 3 is a plan view of FIG. 2, and FIG. 5 is a sectional view of the main part showing the second embodiment of the present invention, FIG. 6 is a sectional view showing a modification of FIG. 5, and FIG. 7 is a sectional view of the main part of the second embodiment of the present invention. 8 is a sectional view of the main part showing the third embodiment, FIG. 8 is a view taken in the direction of the ■ arrow in FIG. 7, FIG. 9 is a sectional view of a heat exchanger showing a conventional example, and FIG. FIG.

Claims (1)

[Claims] Wave-shaped plate fins and flat plate-shaped separators are alternately stacked to form a heat exchange fluid flow path, and distance plates are installed at both ends of the plate fins to regulate the distance between the separators. A plate-fin type heat exchanger, characterized in that the joint portions of the distance plate and the separator exposed to the outside are welded together in the stacking direction.