JP5420970B2 - Heat exchanger - Google Patents

Description

  The present invention relates to a heat exchanger that condenses and removes moisture contained in air supplied to a small fuel cell, and a heat exchanger that is suitable for an exhaust gas cooling heat exchanger (EGR cooler) of an internal combustion engine.

  When the moisture contained in the fuel gas supplied to the small fuel cell or the gas discharged from the fuel cell is condensed, or when the moisture is condensed from the reformed combustion exhaust gas, the stack type is small and has good heat exchange efficiency. A heat exchanger (or condenser) is used (see, for example, Patent Document 1).

  FIG. 11 is a cross-sectional view of a conventional stacked heat exchanger. The heat exchanger 1 includes a core 2 in which a plurality of flat tubes are stacked with a gap therebetween, a casing 3 covering the core 2, and an inlet tank 4 and an outlet tank 5 for heat exchange media provided at both ends of the casing 3. And a coolant supply port 6 and a coolant discharge port 7 provided in the casing 3 apart from each other along the axial direction of the flat tube. The heat exchange medium is, for example, fuel gas supplied to the small fuel cell, and the coolant is cooling water that exchanges heat with the heat exchange medium.

  The heat exchange medium flows into the core 2 from the inlet tank 4, flows through the flat tubes constituting the core 2, and flows out from the outlet tank 5. On the other hand, the coolant flows into the core 2 from the coolant supply port 6, flows through the outer circumference of each flat tube constituting the core 2, and flows out from the coolant discharge port 7. The heat exchange medium exchanges heat with the coolant while passing through each flat tube.

  In order to increase the heat exchange efficiency (or heat exchange amount), it is important that the coolant flows as uniformly as possible through the gaps between the flat tubes. Although the core 2 generally employed as shown in FIG. 11 has a relatively long and narrow shape, the cooling liquid flowing in from the cooling liquid supply port 6 is biased toward the path having the smallest flow resistance as much as possible, that is, the shortest path. There is a tendency toward the outlet 7. In such a case, the amount of the coolant flowing through the region A on the coolant supply port 6 side and the region B on the coolant discharge port 7 side indicated by the dotted line in FIG. 11 decreases, and the coolant flow as a whole is uneven. There is a problem that the heat exchange efficiency decreases due to the distribution.

  FIG. 12 is a partial cross-sectional view specifically showing the structure of a heat exchanger conventionally proposed to solve the above problem. The heat exchanger 1 is different from the heat exchanger 1 of FIG. 11 in that a shielding plate 8 is attached to the outlet of the coolant supply port 6 having a small tank. That is, by mounting the shielding plate 8 at the outlet of the small tank, the cooling liquid flowing in from the cooling liquid supply port 6 causes the shielding plate 8 to flow into the core 3 in the direction opposite to the cooling liquid discharge port 7 side (drawing). It can be biased to the left side (A region side shown in FIG. 11). As a result, the coolant is sufficiently supplied also to the region A shown in FIG. 11, and the phenomenon of a decrease in the coolant flow rate can be prevented. Further, since the coolant flow through the core 3 becomes more uniform, the phenomenon of a decrease in the coolant flow rate in the downstream region B can be avoided. In FIG. 12, a flange 9 for pipe connection is shown in the inlet tank of the heat exchange medium for reference.

JP 2006-284004 A

  However, in the structure of the heat exchanger 1 shown in FIG. 12, it is necessary to separately attach the shielding plate 8 to the portion of the coolant supply port 6, so that the number of parts increases and the number of manufacturing processes increases accordingly. There's a problem. Then, this invention makes it a subject to provide the new heat exchanger which solved this problem.

The heat exchanger of the present invention that solves the above problems includes a core (2) in which a plurality of flat tubes (10) each having an inner fin (14) are stacked with a gap (13a) therebetween, and a core ( 2) a pair of inlet tanks (4) and outlet tanks (5) connected to both ends, and a casing (3) covering the outside of the core (2), and each of the flat tubes (10) includes the inlet tanks. The heat exchange medium for cooling flows through (4), and the coolant supply port (6) for supplying the coolant to the outer surface of the flat tube (10) is located on the inlet tank (4) side. In the heat exchanger provided in the casing (3) with the coolant discharge port (7) positioned on the outlet tank (5) side,
The flat tube (10) is formed by fitting the inner surfaces of both side walls (11b) of the groove-shaped first plate (11) to the outer surfaces of both side walls (12b) of the groove-shaped second plate (12), Expanded portions (10c) are formed at both longitudinal ends of both plates (11) and (12), and the ends of the flat tubes (10) are liquid-tightly stacked with each other by the expanded portions, and the core ( 2) is formed, thereby forming a heat exchanger that does not require a tube plate,
At the position facing the coolant supply port (6), the side wall (11b) of each first plate (11) reaches the edge of the flat tube (10) adjacent in the stacking direction, and is adjacent to it. The gap (13) between the flat tubes (10) is partially closed, and a closed portion (110) is formed by an assembly in which the gaps of the flat tubes (10) are respectively closed. An enlarged opening (15b) of the liquid supply part is formed in a groove shape in the laminating direction so that one side faces (110), and the respective gaps are opened on the other side, and the cooling liquid supply port (6) Further, the heat exchanger is characterized in that the openings of the gaps (13a) between the flat tubes (10) are arranged more biased toward the inlet tank (4) side (Claim 1).

In the heat exchanger, a plurality of dimples (13) projecting outward from the groove bottom of the first plate (11) of one adjacent flat tube (10) and a second of the other adjacent flat tube (10). A plurality of dimples (13) projecting outward from the groove bottom of the plate (12) are in contact with each other, and through holes (17) are coaxially formed in each pair of dimples (13) in contact with each other. The heat exchange is characterized in that the brazing material (18) is disposed inside the (13), melted, and the inner fin (14) and the dimples (13) in contact with each other are integrally brazed. ( Claim 2 ).

Further, any one of the above heat exchangers is formed such that the thickness of the first plate (11) and the second plate (12) is in the range of 0.2 to 0.6 mm, and the diameter of the through hole (17) is the plate. It can be formed in a range larger than the thickness and smaller than 1.5 mm ( claim 3 ).

In the heat exchanger according to the present invention, as described in claim 1, the flat tube includes a groove-shaped first plate and a groove-shaped second plate, and the first tube is disposed inside the both side walls of the first plate. A flat tube is formed with the two side walls of the two plates inserted, and the entrance of the gap between the flat tubes at the position facing the coolant supply port is shielded by each side wall of the tube constituent member, By forming the closed portion (10), the opening of the gap (13a) of each flat tube (10) is arranged more biased toward the inlet tank (4) than the coolant supply port (6). .

In this way, by closing the opposing portion of the cooling liquid supply port with an assembly of many side walls , the cooling liquid flowing in from the cooling liquid inlet port bypasses the cooling liquid supply port portion without shielding, and the gap between the flat tubes. It flows in a biased direction. Then, the non-uniformity of the coolant flowing through the gaps between the flat tubes is improved, and the phenomenon that the coolant flow rate decreases in the regions A and B as shown in FIG. 11 is eliminated. Thus, according to the heat exchanger of the present invention, the assembly of the structure of the flat tube itself also functions as the shielding plate 8 shown in FIG. 12, so that the overall structure and manufacturing process of the heat exchanger can be simplified. Become.

Further, in any one of the above heat exchangers, as described in claim 2 , a plurality of dimples projecting outward from a first plate of one adjacent flat tube and a second plate of the other adjacent flat tube A plurality of dimples projecting outward are in contact with each other, a through hole is formed coaxially in each pair of dimples in contact with each other, a brazing material is disposed inside one dimple, and it is melted to form an inner fin. The dimples that are in contact with each other can be integrally brazed.

  When laminating a plurality of flat tubes with corrugated inner fins inside, conventionally, a brazing material is applied to the inside of the flat tube and the fins are brazed into the flat tube, and then to the outside of the flat tube. Brazing material was applied to braze the flat tubes. However, such a brazing structure requires a two-stage brazing coating process, and the amount of the brazing material that adheres increases. In contrast, in the case of the present invention, when a brazing material is applied between the flat tube and the fin and the flat tube is laminated and heated and brazed, the brazing material flows out through the through hole, and the flat tube and the fin. And the flat tubes are brazed together. Therefore, the three members are integrated with a common brazing material by a single brazing process, and the amount of the brazing material attached to the core is reduced.

In the heat exchanger provided with the dimple, as described in claim 3 , the first plate and the second plate are formed to have the same thickness in the range of 0.2 to 0.6 mm, and the diameters of the through holes are set to the same. It can be formed in a range larger than the plate thickness and smaller than 1.5 mm. With this configuration, the amount of brazing material flowing out from the inside of one flat tube to the other flat tube through the through hole is in an optimum range, and the flat tube and the fins are surely integrated with each other. Can be attached.

The whole heat exchanger of the present invention sectional drawing. The partial expansion perspective view of FIG. III-III sectional drawing of FIG. IV-IV sectional drawing of FIG. FIG. 3 is an enlarged cross-sectional view of a coolant supply port 6 and its peripheral portion shown in FIGS. Sectional drawing which expands and shows a part of casing 3 which comprises the heat exchanger 1. FIG. VII-VII sectional drawing of FIG. VIII-VIII sectional drawing of FIG. The figure which shows the confirmation experiment data of the effect of the swelling structure of the casing 3 shown in FIGS. The fragmentary sectional view explaining the brazing method of the flat tube 10 and the inner fin 14 of the heat exchanger of FIG. Sectional drawing of the conventional laminated heat exchanger. The fragmentary sectional view which shows the structure of the conventional heat exchanger concretely.

  Next, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the heat exchanger 1 includes a core 2 formed by laminating a plurality of flat tubes 10 in a multistage manner with a gap 13 a between them except for both ends, and a casing 3 that covers the outside of the core 2. And an inlet tank 4 and an outlet tank 5 provided at both ends of the core 2, and a coolant supply port 6 and a coolant discharge port 7 provided in the casing 3 apart from each other along the axial direction of the flat tube. ing. The flat tube 10 and the casing 3 are made of a metal material such as aluminum, an aluminum alloy, or stainless steel.

  When the moisture contained in the fuel gas supplied to the small fuel cell from the inlet tank or the gas discharged from the fuel cell is condensed or the moisture is condensed from the reformed combustion exhaust gas, the heat exchange medium is the core 2. , Flows through each flat tube 10 and flows out from the outlet tank 5.

  On the other hand, the coolant flowing into the core 2 from the coolant supply port 6 exchanges heat with the heat exchange medium while flowing through the outer surface of each flat tube 10 and flows out from the coolant discharge port 7. In FIG. 1, the relationship between the inflow of gas and the cooling water supply port 6 is described as a parallel flow, but there is a case where the cooling water discharge port 7 flows in a counter flow on the cooling water supply side. In addition, in FIG. 1, only the cooling water supply port 6 is described as the closing portion 110, but it is also possible to provide four places from the viewpoint of assembly of parts.

  As shown in FIG. 2, FIG. 3, FIG. 4, etc., the flat tube 10 has a flat first portion 11a having a flat bottom portion 11a serving as a groove bottom and side walls 11b formed by bending both end portions thereof at right angles (or substantially right angles). The plate 11 includes a groove-shaped second plate 12 having a flat portion 12a and side walls 12b formed by bending both ends of the flat portion 12a at right angles (or substantially right angles), and the inner side of both side walls 11b of the first plate 11 The flat tube 10 is formed with both side walls 12b of the second plate inserted. Expanded portions 10c are formed at both ends of each flat tube 10, and the ends of the flat tubes 10 are in close contact with each other at the expanded portion 10c.

  When the flat portions 11a of the first plate 11 and the flat portions 12a of the second plate 12 are formed with a plurality of dimples 13 projecting in a frustoconical shape on the outer sides, uniformly distributed, and when the plurality of flat tubes 10 are laminated In addition, a plurality of dimples 13 protruding outward from the first plate 11 of one adjacent flat tube 10 and a plurality of dimples 13 protruding outward from the second plate of the other adjacent flat tube 10 contact each other. A gap 13a is formed. Inside each flat tube 10, inner fins 14 such as straight fins, wave fins, offset fins (multi-entry fins) having a corrugated cross section made of aluminum, an aluminum alloy, stainless steel, or the like are arranged.

  FIG. 3 is a cross-sectional view of the flat tube 10 in the vicinity of the coolant supply port 6, and the tip of the side wall 11 b of the first plate 11 in the flat tube 10 is extended below the outer surface of the flat portion 12 a of the second plate 12. ing. Therefore, the entrance of the gap 13 a between adjacent flat tubes 10 is shielded by the end portion orthogonal to the axial direction of the flat tubes 10. Note that the opposite end not shown in FIG. 3 is the same as the end shown in FIG. 4 described later.

  FIG. 4 is a cross-sectional view of the flat tube 10 including the side wall 11b other than the vicinity of the coolant supply port 6. The tip of the side wall 11b extends to the vicinity of the outer surface of the flat portion 12a of the second plate 12, and the adjacent flat tube The entrances of the ten gaps 13a are not shielded. This is the same for the opposite end not shown in FIG.

  FIG. 5 is an explanatory diagram of an enlarged cross section of the coolant supply port 6 and its peripheral portion shown in FIGS. 1 and 2. The coolant supply port 6 communicates with a coolant supply pipe (not shown) that supplies the coolant to the heat exchanger 1. In this embodiment, a fluid supply unit 15 as shown is provided for the communication. The liquid supply part 15 has a connection part 15a connected to the coolant supply pipe, and an enlarged opening part 15b (which constitutes a small tank) whose diameter gradually increases from the connection part 15a. The coolant supply port 6 is also used.

  A part of the coolant supply port 6 (enlarged opening 15b) is shielded at the entrance of the gap between the tubes by the side wall 11b of each flat tube 10 facing the coolant supply port 6 (enlarged opening 15b). Specifically, as shown in FIGS. 1 and 3, the portion of the opposed surface of the coolant supply port 6 that is biased toward the coolant discharge port 7 is shielded from the side wall 11 b of the first plate 11 of the flat tube 10. The part 110 is shielded. The coolant that flows straight from the connection portion 15a of the liquid supply portion 15 and flows in as indicated by an arrow enters the enlarged opening portion 15b, the flow velocity thereof is reduced, and then the shielding portion 110 by the side wall 11b of the flat tube 10 does not exist. It detours from the part as shown by the arrow and flows into the gap 13a of each flat tube 10.

  At that time, the coolant flows in a direction biased to the side opposite to the coolant discharge port 7 side (inlet tank 4 side), so that it is possible to avoid the phenomenon that the coolant flow rate decreases in the regions A and B shown in FIG. In this embodiment, when the diameter of the connecting portion 15a is R, the diameter of the enlarged opening 15b (diameter of the coolant supply port 6) that is coaxially enlarged is set to twice that. The portion of the coolant supply port 6 that overlaps the connecting portion 15a is shielded by the side wall 11b of the flat tube 10, so that the coolant flows out from the open region that is not shielded as indicated by the arrow.

  6 is an enlarged sectional view showing a side wall portion of the casing 3 constituting the heat exchanger 1, FIG. 7 is a sectional view taken along line VII-VII in FIG. 6, and FIG. 8 is a sectional view taken along line VIII-VIII in FIG. FIG. 6 shows a portion of the casing 3 that is orthogonal to the axial direction of the flat tube 10, and a plurality of side wall portions of the casing 3 are bulged outwardly at a predetermined interval as shown in the figure. The bulging portions 3a and the non-bulging portions 3b are alternately present in the casing 3 along the axial direction.

  FIG. 7 shows the side wall of the flat tube 10 and the non-bulged portion 3b of the casing 3 opposed thereto, and the outer surface of the side wall of the flat tube 10 and the inner surface of the non-bulged portion 3b of the casing 3 are in contact with each other. Yes. 8 shows the side wall of the flat tube 10 and the bulging portion 3a of the casing 3 opposite to the side wall, and the outer surface of the side wall of the flat tube 10 and the inner surface of the bulging portion 3a of the casing 3 are separated by a predetermined distance. Yes.

  In the portion of the non-bulged portion 3b of the casing 3, the outer surface of the side wall of the flat tube 10 and the inner surface of the non-bulged portion 3b of the casing 3 are in contact with each other, so that the cooling liquid is parallel to the stacking direction of the stacked flat tubes 10. Only the gaps 13a are distributed. However, in the portion of the bulging portion 3a of the casing 3, the outer surface of the side wall of the flat tube 10 and the inner surface of the bulging portion a of the casing 3 are separated by a predetermined distance. A gap communication path 16 that communicates the gaps 13a parallel to the stacking direction is formed. For this reason, in the bulging portion 3 a, the coolant flows in the gap 13 a of each stage of the flat tube 10, and also bypass circulation between the gaps 13 a of each stage by the gap communication path 16 occurs.

  FIG. 9 is experimental data in which the effect of providing the bulging structure of the casing 3 shown in FIGS. 6 to 8 is confirmed. The width of the gap 13a of the flat tube 10 is d, the length of the bulging portion 3a shown in FIG. 6 is a, the length of the non-bulging portion 3b is b, and the width of the gap communication passage 16 shown in FIG. FIG. 9 shows the change in the amount of heat (heat exchange amount) with respect to a / b for each relationship of c: d.

  In the experiment, b was 3 to 6 mm, d was 1 to 2 mm, and the flow rate of the coolant was 0.1 to 2.04 liters / minute. From this experimental result, if the case where the casing 3 is not provided with the bulging portion 3a is used as a reference, the heat exchange amount higher than that is obtained in any case where the bulging portion 3a is provided. When a / b is increased from 0.5 to 2, the amount of heat exchange also tends to increase accordingly, and when a / b exceeds 2, the increasing tendency becomes moderate.

  FIG. 10 is a partial cross-sectional view illustrating a method of brazing the flat tube 10 and the inner fin 14 of the heat exchanger 1 shown in FIG. Each flat tube 10 to be laminated is formed by a first plate 11 and a second plate 12, and a plurality of dimples 13 protrude outward from the flat portion 11 a of the first plate 11 and the flat portion 12 a of the second plate 12. Yes.

  Each dimple 13 formed on the flat portion 11a of the first plate 11 in one adjacent flat tube 10 and each dimple 13 formed on the flat portion 12a of the second plate 12 in the other flat tube 10 adjacent thereto are By contacting each other, a gap 13 a is formed between the adjacent flat tubes 10, and through holes 17 are formed coaxially in the contact portions (flat portions of the truncated cone shape) of each dimple 13.

  In order to ensure the strength of the core 2, it is necessary to fix between the outer sides of the two adjacent flat tubes 10 and between the flat tubes 10 and the corrugated inner fins 14 disposed therein. In the present embodiment, when brazing, a paste-like brazing material 18 is first applied to the inside of each dimple 13 of the second plate 12 that forms the flat tube 10.

  Next, after placing a part of the corrugated inner fin 14 (the valley of the inner fin 14 shown in FIG. 10) in contact with the brazing material 18, the first plate 11 is placed on the second plate 12. Assemble. The brazing preparation of one flat tube 10 is completed by the application process of the brazing material 18 and the arrangement process of the inner fins 14. This brazing preparation is performed for each flat tube 10 constituting the core 2. Next, each flat tube 10 ready for brazing is stacked to assemble the core 2, and the inlet tank and the outlet tank are fitted to both sides of the core, and the casing 3 is fitted to the outer periphery of the core. To fix each other. Next, the assembled heat exchanger is put into a heating furnace and brazed together. When brazing, the flat tubes 10 are arranged in the furnace so that the second plate 12 side of each flat tube 10 faces upward in the state shown in FIG.

  When the paste-like brazing material 18 is heated and melted, the contact portion between the inner side of the second plate 12 of the flat tube 10 and the corrugated inner fin 14 is brazed. At the same time, a part of the brazing material 18 passes through the through hole 17 formed in the dimple 13 of the first plate 11, and further flows down to the first plate 11 of the flat tube 10 on the lower side, and a part of the brazing material 18 that has flowed down falls. It flows into a through hole 17 formed in the dimple 13 of the first plate 11. Accordingly, the dimples 13 of the upper flat tube 10 and the dimples 13 of the lower flat tube 10 are brazed at their respective contact surfaces and through holes 17. In this manner, the flat tubes 10 and the corrugated inner fins 14 and the adjacent flat tubes 10 are brazed in a single brazing process.

  The heat exchanger of the present invention condenses moisture contained in the temperature of the fuel gas or air supplied to the small fuel cell or the gas discharged from the fuel cell, or condenses moisture from the reformed combustion exhaust gas. The heat exchanger can be used as a heat exchanger suitable for an EGR cooler or the like.

DESCRIPTION OF SYMBOLS 1 Heat exchanger 2 Core 3 Casing 3a Expansion part 3b Non-expansion part 4 Inlet tank 5 Outlet tank

6 Coolant Supply Port 7 Coolant Discharge Port 8 Shielding Plate 9 Flange 10 Flat Tube 10c Expanded Part 11 First Plate 11a Flat Part 11b Side Wall

12 Second plate 12a Flat portion 12b Side wall 13 Dimple 13a Gap 14 Inner fin

DESCRIPTION OF SYMBOLS 15 Liquid supply part 15a Connection part 15b Expansion opening part 16 Gap communication path 17 Through-hole 18 Brazing material
110 Blocking part

Claims (3)

A core (2) in which a plurality of flat tubes (10) each having an inner fin (14) are stacked with a gap (13a) between each other, and a pair of inlet tanks (4) connected to both ends of the core (2) ) And an outlet tank (5), and a casing (3) covering the outside of the core (2), and in each flat tube (10), a heat exchange medium for cooling via the inlet tank (4) The coolant supply port (6) for supplying the coolant to the outer surface of the flat tube (10) is located on the inlet tank (4) side, and the coolant discharge port (7) is connected to the outlet tank (10). 5) In the heat exchanger provided on the casing (3) located on the side,
The flat tube (10) is formed by fitting the inner surfaces of both side walls (11b) of the groove-shaped first plate (11) to the outer surfaces of both side walls (12b) of the groove-shaped second plate (12), Expanded portions (10c) are formed at both longitudinal ends of both plates (11) and (12), and the ends of the flat tubes (10) are liquid-tightly stacked with each other by the expanded portions, and the core ( 2) is formed, thereby forming a heat exchanger that does not require a tube plate,
At the position facing the coolant supply port (6), the side wall (11b) of each first plate (11) reaches the edge of the flat tube (10) adjacent in the stacking direction, and is adjacent to it. The gap (13) between the flat tubes (10) is partially closed, and a closed portion (110) is formed by an assembly in which the gaps of the flat tubes (10) are respectively closed. An enlarged opening (15b) of the liquid supply part is formed in a groove shape in the laminating direction so that one side faces (110), and the respective gaps are opened on the other side, and the cooling liquid supply port (6) Further, the heat exchanger is characterized in that the openings of the gaps (13a) between the flat tubes (10) are arranged more biased toward the inlet tank (4) side. In claim 1,
A plurality of dimples (13) projecting outward from the groove bottom of the first plate (11) of one adjacent flat tube (10) and a groove of the second plate (12) of the other adjacent flat tube (10) A plurality of dimples (13) projecting outward from the bottom are brought into contact with each other, and through holes (17) are coaxially formed in each pair of dimples (13) in contact with each other, inside one dimple (13). A heat exchanger characterized in that a brazing material (18) is disposed and melted so that an inner fin (14) and dimples (13) contacting each other are brazed together. In claim 2 ,
The plate thickness of the first plate (11) and the second plate (12) is formed in the range of 0.2 to 0.6 mm, and the diameter of the through hole (17) is larger than the plate thickness and from 1.5 mm A heat exchanger characterized by being formed in a small range.

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