JPH051865A - Aluminum made condenser for air condioner - Google Patents

Abstract

PURPOSE:To obtain a condenser which minimizes pressure loss and enhances pressure resistance by dividing a refrigerant passage of heat exchanger tube groups into inlet side passage groups and outlet side passage groups by means of partitioning the interior of a header and relatively reducing the cross sectional area of the exit side passage groups compared with the inlet side passage groups. CONSTITUTION:Each of partitioning boards 9 and 10 is installed respectively in headers 3 and 4 on the both sides so that each of the headers 3 and 4 may be partitioned longitudinally where they are respectively divided into two chambers, say, upper and lower chambers. Furthermore, the partitioning board 9 on the left side is installed more or less on an upper position on the central part of the header 3 whereas the partitioning board 10 is installed to such a position which shares one third of the entire length from the lower end. As a result, as the refrigerant flows from an inlet side passage group A of tube groups equivalent to a condensation section or further from an intermediate passage group B up to an outlet side passage group C equivalent to an excess cooling section, the passage cross sectional area of each flow passage group is reduced so that the pressure loss due to the circulation of refrigerant may be reduced. It is, therefore, possible to carry out heat exchange with high efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum condenser for an air conditioner, and more particularly to an aluminum condenser for a car cooler.

In this specification, the term aluminum is used to include an aluminum alloy.

[0003]

2. Description of the Related Art A heat exchanger used as a condenser for a car cooler has excellent pressure resistance in terms of safety because a relatively high pressure gas is used as a refrigerant. Is required.

Therefore, conventionally, a serpentine tube type heat exchanger is generally used. That is, a generally extruded flat tube called a harmonica tube is bent in a meandering shape, and fins are arranged between parallel portions to form a core.

However, in such a serpentine type condenser, one of the essential problems is that the refrigerant circuit is formed in a meandering manner in one tube from one end to the other end. Therefore, there is a problem that the flow resistance of the refrigerant becomes relatively large. In order to reduce this flow resistance, it is considered to expand the width of the tube and increase the cross-sectional area of the passage, but the size of the condenser core is restricted by its installation space. Means are difficult to apply.

Further, in order to increase the heat exchange efficiency of the condenser, in addition to expanding the width of the tubes to reduce the pressure loss of the refrigerant as described above, the interval between adjacent tubes,
That is, it is considered to reduce the fin height and increase the number of fins interposed between the parallel portions of the tube. However, since the tube material cannot reduce the radius of curvature of its bent portion to a certain value or more due to processing, there is a limit in improving heat exchange efficiency by narrowing the tube interval.

By the way, in the case of a condenser, its refrigerant passage is large in a refrigerant condensing section near the inlet side where the refrigerant is still in a gasified state and in a supercooling section near the outlet side where the refrigerant is in a liquefied state. Be separated. Therefore, in order to secure a large heat exchange efficiency, it is generally necessary to secure a large heat transfer area in the condensing section, and the heat transfer area in the supercooling section may be relatively small. However, in the case of the conventional serpentine tube type, since the refrigerant passage is formed by one tube, it is essentially impossible to change the passage cross-sectional area between the condensing section and the supercooling section. is there. as a result,
According to the phase change of the refrigerant from gas to liquid, the heat exchange efficiency decreases as the refrigerant progresses from the inlet side to the outlet side, and it becomes necessary to form the heat exchange tube extra long. As described above, there is a problem in that heat exchange cannot be performed according to the phase change of the refrigerant, the heat exchange efficiency is poor, and the entire condenser becomes large, and in addition, a large compressor is required.

As described above, the structure of the conventional serpentine type condenser has a limit in design specifications that can be adopted in order to reduce pressure loss and improve heat exchange efficiency.

In addition, in terms of manufacturing, in addition to the fact that the meandering bending process of the tube is somewhat troublesome, the assembling of the tube and the fin tends to expand the meandering bending state of the tube by inserting the fin. Therefore, it is difficult to perform the assembly by means of mechanical automatic assembly,
There was a problem that productivity was low and cost was high as a result.

[0010]

Therefore, the present invention is
To provide a new type of aluminum condenser for an air conditioner that has a large cross-sectional area of the refrigerant passage without increasing the size of the condenser core and has excellent pressure resistance that can reduce pressure loss. With the goal.

Further, for another purpose, the condenser may be such that the cross-sectional area of each passage is changed between the condensing section for exclusively condensing the refrigerant gas and the supercooling section where the liquefied refrigerant mainly flows. Is to provide.

Still another object is to provide a condenser which can be easily assembled and manufactured, has high production efficiency, and can be reduced in cost.

[0013]

For the above object, the aluminum condenser for an air conditioner according to the present invention has a pair of headers which are arranged in parallel to each other and are spaced apart from each other. A plurality of heat exchange tubes connected in parallel to the header and arranged in parallel with each other, and fins arranged in an air circulation gap between adjacent tubes are provided, and each of the headers has a substantially circular cross section. It is composed of a clad tube in which either or both of the inner surface and the outer surface of the aluminum tube is coated with a brazing filler metal layer, and the tube has a flat cross section and has a flat reinforcing wall extending between the upper and lower walls inside. Both ends of the tube are made of aluminum pipe and are inserted into the tube insertion hole formed in the header so that the entire circumference of the tube edge is inside the header. Is inserted in a mode of forming a protrusion having a predetermined length and is brazed in a liquid-tight state by the brazing material layer, and the inside of at least one header is partitioned in the lengthwise direction by partitioning means, The refrigerant passage constituted by the heat exchange tube group is divided into at least two passage groups including an inlet side passage group and an outlet side passage group, and the passage of the outlet side passage group with respect to the inlet side passage group. The cross-sectional area is set to be relatively small.

[0014]

Next, the operation and embodiment of the present invention will be described.

The condenser according to the present invention is, as shown in FIG. 2, arranged between a large number of tubes (1) arranged in parallel in the horizontal direction and adjacent tubes (1) (1). Corrugated fins (2) and a pair of left and right headers (3) and (4) arranged in parallel at right angles to both ends of the tube group.

The tube (1) is made of a flat extruded material made of an aluminum material, and has a reinforcing wall (1a) which extends between the upper and lower walls at the center in the width direction as shown in FIG. It is designed to withstand a large internal pressure applied without any hindrance, and this reinforcing wall (1
According to a), the surface area of the internal refrigerant passage is increased, which contributes to the improvement of heat exchange efficiency. It should be noted that the tube (1) may be of a porous type such as a so-called harmonica tube having a larger number of passage units. Alternatively, an electric resistance welded pipe may be used instead of the extruded mold material, and a reinforcing member corresponding to the reinforcing wall (1a) may be inserted and joined inside. The corrugated fin (2) has almost the same width as the tube (1) and is joined to the tube by brazing. The corrugated fin (2) is also made of aluminum, and it is preferable to use a louver cut and raised.

The headers (3) and (4) are made of aluminum pipe material having a circular cross section. When the tube insertion holes (14) are formed in each header at intervals along the length direction, both ends of each tube (1) are inserted into the holes and are firmly fixed by brazing. It is joined and connected. Moreover, at both ends of the tube (1), as shown in FIG. 4, the entire circumference of the edge projects inward from the inner surface of the header (3) (4), and the inside of the header (3) (4) It is inserted in such a manner that the protrusion (16) having a predetermined length is formed in the. That is, both ends of the tube (1) are inserted in such a manner that both ends in the width direction of the tube (1) protrude inward from the inner surfaces of the headers (3) and (4) with a length (L).
The protrusion (16) formed by this constitutes a kind of baffle in the headers (3) and (4) and promotes the gas-liquid mixing action of the refrigerant as described later, and the tube (1). ) And the headers (3) and (4) are firmly joined, and the brazing filler metal (13b) forms the passage unit (20a) at the end of the tube (1) particularly in the width direction.
It is useful in that it has the function of preventing entry into (20b). Further, a refrigerant inlet pipe (5) is connected to the upper end of the left header (3) and a closing lid piece (7) is attached to the lower end thereof, while a refrigerant outlet pipe is attached to the lower end of the right header (4). (6) are connected, and a closing lid piece (8) is attached to the upper end thereof. Note that (11) (1
2) are upper and lower side plates arranged outside the outermost corrugated fins (2) (2).

By the way, in each of the headers (3) and (4) on both sides, one partition plate (9) (10) is provided, so that the inside of each header (3) (3) is lengthwise. It is divided into two compartments, an upper room and a lower room. Moreover, the partition plate (9) on the left side is provided at the center of the header (3) or at a position above it, and the partition plate (10) on the right side is provided at a position about 1/3 of the entire length from the lower end.

By installing the partition plates (9) and (10) as described above, all the refrigerant passages (20) constituted by the tube (1) group (see FIG. 6) are connected to the inlet side passage group (A). The outlet side passage group (C) and the intermediate passage group (B) located in the middle of the passage side passage group (C) are divided into three passage groups, and the refrigerant is sequentially circulated in a meandering manner around each passage group.
In addition, the intermediate passage group (B) includes a larger number of tubes than the outlet side passage group (C), that is, the number of refrigerant passages, and the passage cross sectional area thereof is larger than the passage cross sectional area of the outlet side passage group (C). Further, the passage sectional area of the inlet side passage group (A) is set to be larger than the passage sectional area of the intermediate passage group (B).

In the above structure, the refrigerant flowing from the upper inlet pipe (5) of the left header (3) passes through each tube (1) of the inlet side passage group (A) as shown in FIG. After reaching the right header (4), it reverses to flow through each passage of the intermediate passage group (B) to the left header (3), and further reverses to pass each passage of the outlet side passage group (C) to the right header. And flows out of the condenser through the outlet pipe (6). Then, while flowing through each passage group, the air flowing through the air flow gap including the corrugated fins (2) formed between the tubes (1) and (1) in the direction indicated by the arrow (W) in FIG. Heat exchange. Further, as described above, the refrigerant is the header (3).
When reversing in the header (3) (4), the end of the tube (1) projects into the header (3) (4) to form a protrusion (16). The mixing action of the refrigerant, that is, the gas-liquid mixing action is promoted, and when entering the next refrigerant passage group, it becomes a uniform gas-liquid mixing state and is distributed in each tube (1). Therefore, it is possible to prevent a specific refrigerant passage from being filled with the condensed liquid phase refrigerant and causing a so-called liquid sealing phenomenon.

Although the refrigerant passing through the inlet side passage group (A) is still in a gasified state having a large volume, the passage cross sectional area of the inlet side passage group (A) is set to be large, so Since the heat area is large, the refrigerant is efficiently condensed. A part of the refrigerant passing through the intermediate passage group (B) is liquefied in the inlet side passage group (A), so that it has a gas-liquid mixed state. Therefore, the heat transfer area may be small, but accordingly the passage cross-sectional area of the intermediate passage group (B) is set smaller than that of the inlet side passage group (A), so that necessary and sufficient heat exchange is performed. It is possible to pass the settsu refrigerant. When passing through the outlet side passage group (C), the refrigerant is already in a liquid state and has a small volume, so the passage cross sectional area may be small, but accordingly, the passage side cross sectional area of the outlet side passage group (C) is small. Since it is set to be smaller than the intermediate passage group (B), no space is wasted in passing the refrigerant. In this way, the passage cross-sectional area of each passage group is changed from the inlet side passage group (A) corresponding to the condensing portion to the intermediate passage group (B) to the outlet side passage group (C) corresponding to the supercooling portion. By making it small, efficient heat exchange can be achieved.

In the embodiment described above, the case where the passage cross-sectional area is gradually reduced from the inlet side passage group (A) to the outlet side passage group (C) is shown. ) And the intermediate passage group (B) have the same passage cross-sectional area,
Only the passage cross-sectional area of the outlet side passage group (C) may be reduced. Further, as a means for reducing the passage cross-sectional area of each passage group from the inlet side to the outlet side, a method of changing the number of tubes (1) included in each passage group was adopted. A method of changing the cross-sectional area may be adopted. Further, in the above-mentioned embodiment, the three-pass system in which the three passage groups are provided and the refrigerant is U-turned twice and meandered three times is shown. However, the inlet side passage group (A) and the outlet side passage group (C) are shown. The present invention can also be applied to a two-pass type condenser consisting of only one U-turn and a meandering condenser of four or more passes in which an intermediate passage group is formed in two or more passages.

By the way, the tube (1) and the headers (3) and (4) are joined by brazing with a brazing material layer pre-coated on either the inner surface and / or the outer surface of the header. That is, in the illustrated embodiment, as shown in FIG. 3, a clad tube (13) in which an inner surface of an aluminum tube (13a) is covered with a brazing material layer (13b) is used as a header constituting member. There is. The clad pipe (13) is generally manufactured by electric resistance welding, but it may be manufactured by extrusion or another method. As the brazing material layer (13b),
Generally, Al-containing Si content of about 6 to 13 wt%
A Si-based alloy is used. And such a clad tube (1
After arranging the tube insertion holes (14) in 3), insert the end of the tube (1) into the insertion holes (14) to make a temporary assembly state, and then assemble them together by vacuum brazing or the like. It is joined by attaching. After such brazing, as shown in FIG. 5, at the connecting portion between the headers (3) and (4) and the tube (1), a sufficient fillet () is formed around the protruding portion (16) of the tube (1). 15) is formed, and the headers (3) and (4) and the tube (1) are firmly joined and integrated without a gap. When brazing and fixing the header and the tube, a brazing sheet coated with a brazing material is used as the material for the corrugated fin (2), or as the material for the tube (1).
If a clad tube having a brazing material layer formed on the outer surface side is used, the header (3) (4) and the tube (1) are brazed together with the tube (1) and the corrugated fin (2). Can also be performed, and the productivity of the heat exchanger can be further improved. In the illustrated embodiment, the clad pipe (13) in which only the inner surface of the aluminum pipe (13a) is coated with the brazing material layer (13b) is shown as the constituent member of the headers (3) and (4). The material layer may be formed only on the outer surface of the aluminum pipe (13a), or may be formed on both the inner surface and the outer surface.

[0024]

The present invention has the following operational effects.

(1) First, the pressure loss of the refrigerant can be greatly reduced.

That is, in the condenser according to the present invention, a large number of heat exchange tubes are arranged in a communication connection state between a pair of headers arranged in parallel on the left and right, and introduced from the refrigerant inlet of one header. Since it is configured as a so-called multi-flow type heat exchanger that distributes and distributes the liquid refrigerant to a plurality of tubes at the same time, the refrigerant passage cross-sectional area is particularly within the range of a limited vessel thickness. It is possible to secure an arbitrarily large value, and it is possible to greatly reduce the pressure loss for circulating the refrigerant. Therefore, it is possible to improve the heat exchange efficiency and reduce the required capacity of the compressor.

(2) Further, it has excellent pressure resistance and high safety.

That is, there is a multi-flow type heat exchanger generally known as a radiator in the past.
However, in this known heat exchanger, in many aspects such as the structure of the tank part, the joint structure of the tube and the tank part, and the structure of the tube, in the application as a condenser to which a considerably large internal pressure is applied, It is difficult to secure sufficient pressure resistance to withstand use. However, in the present invention, an aluminum tube having a circular cross section is used as the header, and a tube material having a flat cross section and a reinforcing wall provided between the upper and lower inner walls is used as the heat exchange tube. As a communication connection structure with a header, the end of the tube is brazed into a hole formed in the peripheral wall of the header in a state where the end of the tube is inserted in a protruding state, and the brazing is performed. However, since it has a brazing material layer that has been pre-coated on either or both of the inner surface and outer surface of the header, it has sufficiently excellent pressure resistance and sufficient safety without fear of liquid leakage. It can be made to have durability and durability.

(3) The heat exchange efficiency is excellent and the size can be remarkably reduced.

That is, in the condenser of the present invention,
A pair of headers are arranged in parallel on the left and right, and a large number of tubes are horizontally arranged between them to constitute a horizontal type, and a partition plate is provided inside one or both headers. The refrigerant passage constituted by the tube is divided into at least two passage groups including an inlet side passage group and an outlet side passage group,
The refrigerant is made to make one or more U-turns in the header to be circulated in a meandering manner of two or more passes, and the passage cross-sectional area of the outlet side passage group is set relatively small with respect to the inlet side passage group. It is supposed to be. Therefore, this ensures a necessary and sufficient passage cross-sectional area in each of the condensing part and the subcooling part, which reasonably corresponds to the change in the phase state of the refrigerant, that is, the phase change from the gas state to the liquid state. However, it is possible to secure a required and sufficient length in the refrigerant passage from the inlet to the outlet. In addition, as mentioned above,
The partition means is provided in the header so that the refrigerant that has flowed through each passage group is made to make a U-turn in the header, and the tube end portion protrudes into the header and protrudes inward. And the fact that it functions as a kind of baffle, the refrigerant has a sufficient mixing action when the U-turn is made in the header, that is, a gas-liquid mixing action. In response to this, the temperature is made uniform, and after that, the refrigerant is distributed and introduced into the next refrigerant passage and further cooled. Therefore, for example, as in the case of the conventional serpentine type condenser, as the liquid-phase refrigerant condensed in each refrigerant passage approaches the outlet side in particular, the refrigerant passage is blocked over a large range, or the tube is made vertical. As in the case of the arranged vertical heat exchanger, it is possible to effectively reduce the occurrence of a so-called liquid sealing phenomenon in which the condensed liquid phase refrigerant stays in the lower header by gravity and blocks the refrigerant passage. As a result, the front surface area of the core can be fully utilized as an effective area for heat exchange, and the heat exchange capacity can be significantly improved.

Further, unlike the conventional serpentine type condenser, there is no inconvenience that the tube pitch is limited because the radius of curvature of the bent portion is limited, and a free tube pitch can be selected. If the number of meandering and the total length are the same, the number of corrugated fins interposed between adjacent tubes can be significantly increased by reducing the tube pitch, and fin efficiency can be improved. Therefore, the heat exchange efficiency can be improved, and the overall size of the condenser can be reduced, which can be an optimal condenser for a vehicle applied to a narrow space. The amount of CFC refrigerant used, which poses a social problem as one of the pollution factors, is 30
% Or more can be significantly reduced.

(4) Easy to manufacture and excellent in productivity.

That is, furthermore, the tube and the header in the condenser of the present invention are joined with the brazing material layer coated in advance on at least one of the inner and outer surfaces of the clad tube applied as the header constituent member. Moreover, since the brazing is performed by brazing the end of the tube protruding into the header, the brazing filler metal is prevented from entering the tube from the end while the brazing material is surrounded by the protruding part of the tube. Not only can a sufficient fillet be formed to ensure reliable airtight joining of the two, but also in the assembly and fabrication of the condenser, for example, first insert both ends of the tube into the holes of the header and then the frame-shaped skeleton. And place fins between adjacent tubes to make the whole assembly in a temporarily assembled state, or arrange tubes and fins alternately and then After the temporarily assembled state in combination with chromatography, easily can be carried out by attaching batch brazing in a furnace, it is possible to achieve a reduction of resulting in manufacturing cost increase productivity.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state before temporarily assembling a clad tube, which is a header constituting member, and a tube.

FIG. 2 is an overall front view.

FIG. 3 is a plan view of the same.

4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is an enlarged cross-sectional view taken along line VV of FIG.

FIG. 6 is a refrigerant circuit diagram.

[Explanation of symbols]

 (1) ... Tube (1a) ... Reinforcing wall (2) ... Corrugated fins (3) (4) ... Header (13) ... Clad tube (13a) ... Aluminum tube (13b) ... Brazing material layer (20) ... Refrigerant passage (20a) (20b) ... passage unit (A) ... entrance side passage group (C) ... exit side passage group

Claims (1)

Claim: What is claimed is: 1. A pair of headers arranged in parallel to each other at a distance from each other, and a plurality of heats arranged in parallel by connecting both ends to the headers. The header comprises a replacement tube and fins arranged in an air flow gap between adjacent tubes, and the header has a brazing material layer on either or both of an inner surface and an outer surface of an aluminum tube having a substantially circular cross section. The tube is formed of a clad tube formed by coating, and the tube is a flat aluminum tube having a flat cross section and having a reinforcing wall that extends between the upper and lower walls, and both ends of the tube are formed in the header. The tube insertion hole is inserted into the tube insertion hole in such a manner that the entire circumference of the tube end edge projects inward from the inner surface of the header to form a projection of a predetermined length. The brazing material layer is brazed in a liquid-tight state, and the inside of at least one of the headers is partitioned in the lengthwise direction by the partitioning means, so that the refrigerant passages constituted by the heat exchange tube group form an inlet side passage group and an outlet side The air is characterized in that it is divided into at least two or more passage groups including a side passage group, and the passage cross-sectional area of the outlet side passage group is set to be relatively small with respect to the inlet side passage group. Aluminum condenser for air conditioner.