JP7701779B2 - heat exchanger - Google Patents

Description

The present invention relates to a heat exchanger.

Generally, the outdoor and indoor units of an air conditioner are equipped with a heat exchanger. The heat exchanger operates as an evaporator or a condenser by exchanging heat between the refrigerant flowing inside the heat transfer tube and the air flowing around the fins arranged around the heat transfer tube.

Some heat exchangers have multiple rows of heat transfer tubes stacked at intervals, and refrigerant is shuttled between the rows. Specifically, two refrigerant inlets and outlets are provided at one end of the heat exchanger, and refrigerant flowing in from one inlet and outlet flows through one row of heat transfer tubes to reach the other end of the heat exchanger, where it is folded back by a return header connecting the rows to the other row of heat transfer tubes, and may then return to the end where the other inlet and outlet are provided. By shuttleing the refrigerant in this way, the length of the refrigerant flow path is lengthened, allowing a large amount of refrigerant to evaporate sufficiently.

JP 2011-214827 A JP 2013-242126 A

The folded header that connects the rows of heat transfer tubes is generally formed by joining two plates by brazing. Specifically, the folded header is formed by placing two plates, each having a flat peripheral portion and a recess in the center that is recessed below the flat surface, facing each other with the recesses facing each other, and bonding the peripheral portions together as a brazing allowance. Since the two plates are joined with the recesses facing each other, a space is formed by the opposing recesses. Such a space is formed for each row of heat transfer tubes that are stacked in multiple rows, and a pair of heat transfer tubes located in the same row in different rows are connected by a single space.

That is, a pair of heat transfer tubes in the same row are connected through a space formed by facing the recesses of two plates, which serves as a flow path for refrigerant flowing in opposite directions. A through hole is provided at the bottom of the recess of one of the plates that forms this space, allowing the tips of a pair of heat transfer tubes in the same row but in a different row to pass through. The refrigerant flowing out of one of the pair of heat transfer tubes flows into the other heat transfer tube through the space formed in the folded header.

In this way, the recess formed in the center of the plate forms the space for the folded header, and the peripheral portion of the plate around the recess is used as a brazing allowance. In order to ensure the joining strength of the two plates and form the folded header, it is necessary to increase the area of the brazing allowance. However, increasing the area of the brazing allowance poses the problem that the space occupied by the folded header increases. That is, since the heat transfer tube is connected to the space formed by the recess of the plate, when viewed from the direction in which the heat transfer tube extends, the brazing allowance of the plate extends in a direction that does not overlap with the heat transfer tube (a direction perpendicular to the direction in which the heat transfer tube extends), making it difficult to save space.

The disclosed technology was developed in consideration of these points, and aims to provide a heat exchanger that can save space.

In one aspect, the present application discloses a heat exchanger having a pair of heat transfer tubes that form a flow path for a refrigerant flowing in opposite directions, a plurality of fins that are installed at intervals between each of the pair of heat transfer tubes, and a header that connects the pair of heat transfer tubes and turns the refrigerant from one heat transfer tube to the other heat transfer tube, the header having a first plate-like member through which the pair of heat transfer tubes pass, a second plate-like member that is joined to the first plate-like member, and a space formed between the first plate-like member and the second plate-like member through which the refrigerant can flow from one of the heat transfer tubes, the joint portion formed by the joint surface between the first plate-like member and the second plate-like member has a bent portion that is formed at an end of the joint portion in the direction in which the pair of heat transfer tubes are arranged, and has a length that is located on the fin side closest to the header, extends beyond the penetration surface through which the pair of heat transfer tubes pass, and reaches the fin closest to the header.

One aspect of the heat exchanger disclosed in this application has the effect of saving space.

FIG. 1 is a perspective view showing a configuration of a heat exchanger according to an embodiment. FIG. 2 is a cross-sectional view taken along line II. FIG. 3 is a cross section taken along line II-II. FIG. 4 is a diagram showing the structure of a return header. FIG. 5 is a diagram for explaining the shape of a return header. FIG. 6 is a diagram showing a modified example of the return header.

Below, one embodiment of the heat exchanger disclosed in this application will be described in detail with reference to the drawings. Note that the present invention is not limited to this embodiment.

Figure 1 is a perspective view showing the configuration of a heat exchanger 100 according to one embodiment. The heat exchanger 100 shown in Figure 1 is installed in, for example, an outdoor unit of an air conditioner, and operates as an evaporator or a condenser. The heat exchanger 100 has a heat exchange core 110, a first header 120, a first inlet/outlet 130, a second header 140, a second inlet/outlet 150, and a folded header 170.

The heat exchange core section 110 has an L-shape in plan view, and has two rows of heat transfer tubes stacked in multiple stages. The heat exchange core section 110 also has a number of fins that guide air around the heat transfer tubes and promote heat exchange with the refrigerant flowing inside the heat transfer tubes. Specifically, FIG. 2 is a diagram showing a cross section taken along line I-I in FIG. 1, and FIG. 3 is a diagram showing a cross section taken along line II-II in FIG. 1. Note that detailed illustration of the heat transfer tubes and fins of the heat exchange core section 110 is omitted in FIG. 1.

As shown in FIG. 2, the heat exchange core 110 has a heat transfer tube 111a, a fin 112a, a heat transfer tube 111b, and a fin 112b. The heat exchange core 110 has a row in which the heat transfer tubes 111a are stacked in multiple stages with a gap therebetween and a row in which the heat transfer tubes 111b are stacked in multiple stages with a gap therebetween, and the heat transfer tubes 111a and 111b in the same stage in each row are arranged side by side so that they extend parallel to each other close to each other. The heat transfer tubes 111a and 111b are flat tubes with a flat cross section, and the heat transfer tubes 111a and 111b have the same cross section. In the cross section of the heat transfer tubes 111a and 111b, multiple flow paths of the refrigerant are arranged in the longitudinal direction. Heat transfer tube 111a extends from the first header 120 to the turn-around header 170, and heat transfer tube 111b extends from the second header 140 to the turn-around header 170.

The heat transfer tubes 111a and 111b pass through comb-shaped fins 112a and 112b extending in the stacking direction of the heat transfer tubes 111a and 111b. That is, as shown in FIG. 3, for example, the heat transfer tube 111a passes through multiple fins 112a, and the refrigerant flowing inside the heat transfer tube 111a exchanges heat efficiently with the air passing between the multiple fins 112a. Similarly, the heat transfer tube 111b passes through multiple fins 112b, and the refrigerant flowing inside the heat transfer tube 111b exchanges heat efficiently with the air passing between the multiple fins 112b.

The fins 112a and 112b extend in the stacking direction of the heat transfer tubes 111a and 111b, and the heat transfer tubes 111a and 111b are inserted between the teeth of the comb shape. That is, the fins 112a insert a plurality of heat transfer tubes 111a arranged in a row in the stacking direction, and the fins 112b insert a plurality of heat transfer tubes 111b arranged in a row in the stacking direction. A gap is provided between adjacent fins 112a in the direction in which the heat transfer tubes 111a extend, and the space partitioned by the stacked heat transfer tubes 111a and the adjacent fins 112a becomes an air passage. Heat exchange occurs between the air passing through this passage and the refrigerant flowing in the heat transfer tube 111a. Similarly, a gap is provided between adjacent fins 112b in the direction in which the heat transfer tubes 111b extend, and the space partitioned by the stacked heat transfer tubes 111b and the adjacent fins 112b becomes an air passage. Heat exchange occurs between the air passing through this passage and the refrigerant flowing inside the heat transfer tube 111b.

The first header 120 and the second header 140 are provided at one end of the heat exchanger 100. The first header 120 is connected to a plurality of heat transfer tubes 111a arranged in a row in the stacking direction, and the second header 140 is connected to a plurality of heat transfer tubes 111b arranged in a row in the stacking direction.

When the heat exchanger 100 functions as an evaporator, the first header 120 becomes a refrigerant inlet header and sends the gas-liquid two-phase refrigerant flowing in from the first inlet/outlet 130 to the heat transfer tube 111a. When the heat exchanger 100 functions as a condenser, the first header 120 becomes a refrigerant outlet header and sends the gas-liquid two-phase refrigerant flowing in from the heat transfer tube 111a to the first inlet/outlet 130.

When the heat exchanger 100 functions as an evaporator, the second header 140 becomes an outlet header for the refrigerant, and sends the refrigerant in a two-phase gas-liquid state flowing in from the heat transfer tube 111b to the second inlet/outlet 150. When the heat exchanger 100 functions as a condenser, the second header 140 becomes an inlet header for the refrigerant, and sends the refrigerant in a two-phase gas-liquid state flowing in from the second inlet/outlet 150 to the heat transfer tube 111b.

The turn-back header 170 is provided at the end opposite to the end where the first header 120 and the second header 140 of the heat exchanger 100 are provided, and connects the heat transfer tubes 111a and 111b. That is, the turn-back header 170 has a space where the ends of a pair of heat transfer tubes 111a and 111b in the same stage are commonly connected, and the refrigerant flowing out from the end of the heat transfer tube 111a is turned back to flow into the heat transfer tube 111b, and the refrigerant flowing out from the end of the heat transfer tube 111b is turned back to flow into the heat transfer tube 111a.

Figure 4 is a diagram showing the structure of the folded header 170. Figure 4 is a perspective view of the folded header 170 as seen from the heat transfer tubes 111a and 111b side (i.e., the inside of the heat exchanger 100).

The folded header 170 is formed by joining two plate-like members 171 and 172, for example, by brazing. The end 171a of the plate-like member 171 in the row width direction (hereinafter simply referred to as the "row width direction"), which is the direction in which a pair of heat transfer tubes 111a and 111b of the same row are arranged, is bent toward the heat transfer tubes 111a and 111b, and the end 172a of the plate-like member 172 in the row width direction is also bent toward the heat transfer tubes 111a and 111b. The joint between the end 171a of the plate-like member 171 and the end 172a of the plate-like member 172 forms the bent portion 170a of the folded header 170. In other words, both ends in the row width direction of the joint between the two plate-like members 171 and 172 are bent toward the plate-like member 172 to form the bent portion 170a. For example, plate member 171 corresponds to the "second plate member" in the claims, and plate member 172 corresponds to the "first plate member" in the claims.

In the center of the plate-shaped member 171, recesses 171b are formed for each stage of the heat transfer tubes 111a and 111b, and in the center of the plate-shaped member 172, recesses 172b are formed for each stage of the heat transfer tubes 111a and 111b. The plate-shaped members 171 and 172 are joined so that the recesses 171b and 172b corresponding to the same stages of the heat transfer tubes 111a and 111b face each other, and a space is formed by the recesses 171b and 172b facing each other. The brazing material that joins the plate-shaped members 171 and 172 is contained in, for example, a clad layer formed on the surface of the plate-shaped member 172, and when this clad layer is heated, the brazing material melts and joins the plate-shaped members 171 and 172. The tips of the heat transfer tubes 111a and 111b penetrate the bottom of the recess 172b, and the space formed by the recesses 171b and 172b connects the heat transfer tubes 111a and 111b. In other words, the refrigerant can be turned back and forth between the heat transfer tubes 111a and 111b through the space formed by the recesses 171b and 172b.

The plate-shaped members 171, 172 except for the recesses 171b, 172b are joined to the opposing plate-shaped members 172, 171 by brazing, for example. That is, the plate-shaped member 171 except for the recesses 171b is joined to the plate-shaped member 172 by brazing, for example, and the plate-shaped member 172 except for the recesses 172b is joined to the plate-shaped member 171 by brazing, for example. In order to ensure the joining strength of the plate-shaped members 171, 172, the joints of the plate-shaped members 171, 172 each have an area of a certain degree or more. That is, for example, the folded header 170 shown in FIG. 4 has a relatively large joint area on the side of the recesses 171b, 172b.

The ends 171a, 172a of the joint in the row width direction are the bent portions 170a of the folded header 170, as described above. The bent portions 170a are bent so as to be approximately parallel to the direction in which the heat transfer tubes 111a, 111b that penetrate the bottom of the recess 172b extend. In other words, the bent portions 170a are bent at approximately right angles to the joints around the recesses 171b, 172b.

In this way, by forming the bent portion 170a, the size of the folded header 170 in the column width direction can be reduced even when the area of the joint between the plate-like members 171 and 172 is increased to ensure joint strength. As a result, the space occupied by the folded header 170 can be reduced, resulting in space savings.

Figure 5 is a diagram showing a cross section of a plane perpendicular to the stacking direction of the heat transfer tubes 111a, 111b of the folded header 170 (hereinafter simply referred to as the "stacking direction").

As shown in FIG. 5, plate-like members 171 and 172 are joined together so that the bottoms of recess 171b of plate-like member 171 and recess 172b of plate-like member 172 face each other, forming space 170b that connects heat transfer tubes 111a and 111b. The tips of heat transfer tubes 111a and 111b penetrate the bottom of recess 172b and reach space 170b. As a result, heat transfer tubes 111a and 111b are connected by space 170b.

The portions other than the recesses 171b and 172b are joints that join the plate-like members 171 and 172 by brazing, for example, and both ends of the joint in the row width direction are bent portions 170a that are bent in a direction approximately parallel to the direction in which the heat transfer tubes 111a and 111b extend. That is, the end 171a in the row width direction of the plate-like member 171 is bent toward the heat transfer tubes 111a and 111b, and the end 172a in the row width direction of the plate-like member 172 is bent toward the heat transfer tubes 111a and 111b, and these ends 171a and 172a are joined to form the bent portion 170a.

The bent portion 170a is bent in a direction approximately parallel to the direction in which the heat transfer tubes 111a, 111b that penetrate the bottom of the recess 172b extend, and the tip of the bent portion 170a passes beyond the bottom of the recess 172b and reaches the vicinity of the fins 112a, 112b that are closest to the folded header 170. In other words, the length of the bent portion 170a is longer than the depth of the recess 172b and is approximately equal to the distance between the folded header 170 and the fins 112a, 112b that are closest to the folded header 170.

By making the length of the bent portion 170a longer than the depth of the recess 172b, the ratio of the area second moment at the recesses 171b, 172b of the plate-like members 171, 172 to the area second moment at the joint excluding the recesses 171b, 172b can be efficiently reduced. As a result, the concentration of stress at the joint can be mitigated, and deformation of the folded header 170 at the joint can be prevented.

In addition, by making the length of the bent portion 170a approximately equal to the distance between the folded header 170 and the fins 112a, 112b closest to the folded header 170, the tip of the bent portion 170a reaches the vicinity of the fins 112a, 112b, blocking the air passage between the folded header 170 and the fins 112a, 112b. As a result, the air around the heat exchanger 100 passes between the adjacent fins 112a and between the adjacent fins 112b without passing between the folded header 170 and the fins 112a, 112b, improving the heat exchange efficiency.

As described above, according to this embodiment, at the end in the row width direction of the folded header formed by joining two plate-shaped members, the joint between the two plate-shaped members is bent toward the heat transfer tube. This makes it possible to reduce the size of the folded header in the row width direction while ensuring the area of the joint as the brazing allowance of the plate-shaped members. As a result, the space occupied by the folded header is reduced, and space can be saved.

In the above embodiment, the folded header 170 has the folded portion 170a formed at both ends in the column width direction, but the folded portion may be formed at only one end in the column width direction. Also, the folded portion may be formed at the end of the folded header 170 in the stacking direction. In short, by folding one of the ends of the folded header 170 to form a folded portion, it is possible to save space.

In addition, in the above embodiment, the bent portion 170a is bent in a direction approximately parallel to the extension direction of the heat transfer tubes 111a and 111b, but the angle at which the bent portion 170a is bent may be any angle. However, by bending the bent portion 170a at an angle of 90 degrees or more, the size of the folded header 170 in the row width direction can be minimized. In addition, by bending the bent portion 170a toward the plate-shaped member 172, the bent portion 170a does not protrude to the opposite side of the heat transfer tubes 111a and 111b. As a result, it is possible to prevent the heat exchanger 100 from becoming large in the extension direction of the heat transfer tubes 111a and 111b.

In addition, in the above embodiment, the recesses 171b, 172b are opposed to each other to join the plate-like members 171, 172, thereby forming the space 170b connecting the heat transfer tubes 111a, 111b, but the structure of the folded header 170 is not limited to this. Specifically, for example, as shown in FIG. 6, a spacer 173 may be placed between the plate-like members 171, 172, and the plate-like members 171, 172 sandwiching the spacer 173 may be joined to form the folded header 170. By sandwiching the spacer 173, the space 170b is formed between the plate-like members 171, 172. The tips of the heat transfer tubes 111a, 111b penetrate the plate-like member 172 and reach the space 170b.

Even in the folded header 170 having such a structure, the end portions 171a, 172a of the plate-like members 171, 172 in the row width direction, for example, are bent toward the heat transfer tubes 111a, 111b and joined to form the folded portion 170a. This allows the size of the folded header 170 in the row width direction to be reduced, thereby saving space, even when the area of the joints of the plate-like members 171, 172 is increased to ensure joint strength.

REFERENCE SIGNS LIST 110 Heat exchange core portion 111a, 111b Heat transfer tube 112a, 112b Fin 120 First header 130 First inlet/outlet 140 Second header 150 Second inlet/outlet 170 Folded header 170a Bent portion 170b Space 171, 172 Plate-shaped member 171a, 172a End portion 171b, 172b Recess 173 Spacer

Claims (3)

A heat exchanger having a pair of heat transfer tubes which form flow paths for refrigerant flowing in opposite directions, a plurality of fins which are installed at intervals on each of the pair of heat transfer tubes, and a header which connects the pair of heat transfer tubes and turns the refrigerant from one heat transfer tube to the other heat transfer tube,
The header may include:
A first plate-shaped member through which the pair of heat transfer tubes pass;
a second plate-like member joined to the first plate-like member;
a space formed between the first plate-shaped member and the second plate-shaped member, into which a refrigerant can flow from the one heat transfer tube;
a joint portion formed by a joint surface between the first plate-like member and the second plate-like member has a bent portion,
The bent portion is
a joint portion formed at an end portion in a direction in which the pair of heat transfer tubes are aligned, the joint portion being located on the side of the fin closest to the header, and having a length extending beyond a penetration surface through which the pair of heat transfer tubes penetrate, to the fin closest to the header. The bent portion is
The heat exchanger according to claim 1 , wherein the first plate member is bent toward the first plate member. The bent portion is
3. The heat exchanger according to claim 1, wherein the pair of heat transfer tubes penetrating the first plate-like member are bent in a direction parallel to an extension direction of the pair of heat transfer tubes.

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