JPH0345302B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to condensers, in particular aluminum condensers for car coolers.

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

Conventional technology and its problems Heat exchangers such as those used as condensers for car coolers use relatively high-pressure gas as a refrigerant, so they must have excellent pressure resistance for safety reasons. requested.

For this reason, conventionally, a serpentine tube type heat exchanger is generally used. That is, a core is generally used by bending a multi-hole extruded flat tube called a harmonica tube into a serpentine shape and arranging fins between its parallel parts.

However, one of the essential problems with such a serpentine condenser is that the refrigerant circuit is formed in a meandering manner from one end to the other within one tube. 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 widen the width of the tube and increase the cross-sectional area of the passage, but since the size of the condenser core is limited by its installation space, such measures cannot be taken. The method is difficult to apply.

In addition, to increase the heat exchange efficiency of the condenser,
In addition to increasing the width of the tubes to reduce the pressure loss of the refrigerant as described above, the distance between adjacent tubes, that is, the height of the fins, can be reduced to increase the number of fins interposed between the parallel portions of the tubes. It is also taken into consideration. However, because the radius of curvature of the bent portion of the tube material cannot be made smaller than a certain value due to processing, there is a limit to the improvement in heat exchange efficiency by narrowing the tube spacing.

By the way, in the case of a condenser, the refrigerant passage is roughly divided into a refrigerant condensing section near the inlet side where the refrigerant is still in a gasified state, and a supercooling section near the exit side where the refrigerant is in a liquefied state. Ru. In order to ensure high heat exchange efficiency, it is generally necessary to ensure a large heat transfer area in the condenser, and the heat transfer area in the supercooling section may be relatively small. However, in the case of the conventional serpentine tube type, the refrigerant passage is formed by a single tube, so it is essentially impossible to change the passage cross-sectional area between the condenser and the supercooling section. be. As a result, a so-called liquid seal state occurs in which the liquefied refrigerant blocks the passage as it progresses from the inlet side to the outlet side in response to the phase change of the refrigerant from gas to liquid.This creates heat transfer resistance and reduces heat exchange efficiency. As a result, the heat exchange tube must be made extra long. As described above, heat exchange according to the phase change of the refrigerant cannot be carried out, resulting in poor heat exchange efficiency, resulting in an increase in the size of the entire condenser and, in addition, the need for a large compressor.

As described above, due to the structure of the conventional serpentine condenser, there are limits to the design specifications that can be adopted in order to reduce pressure loss and improve heat exchange efficiency.

In addition, in terms of manufacturing, bending the tube into a serpentine shape is somewhat troublesome, and when assembling the tube and fins, the serpentine bending state of the tube tends to expand as the fins are inserted. Therefore, it is difficult to perform the assembly by automatic mechanical assembly means, resulting in low productivity and high costs.

Problems to be Solved by the Invention Therefore, the present invention has developed a new model with excellent pressure resistance that can ensure a large cross-sectional area of the refrigerant passage without increasing the size of the condenser core, resulting in less pressure loss. The purpose is to provide a condenser for

In addition, for other purposes, it is possible to change the cross-sectional area of each passage between the condenser that exclusively condenses refrigerant gas and the supercooling section where liquefied refrigerant mainly flows, and the tube width and The condenser has a structure that allows tube spacing, ie fin height, etc. to be set to various values, and is also set to optimal conditions to reduce pressure loss of refrigerant and circulating air and improve heat exchange efficiency. The goal is to provide the following.

Yet another purpose is to facilitate assembly and production;
It is an object of the present invention to provide a condenser that has good production efficiency and can reduce costs.

Means for Solving the Problems In the above object, an aluminum condenser according to the present invention includes a pair of aluminum cylindrical headers arranged in parallel with a distance from each other, and having both ends connected to the headers, respectively. A plurality of heat exchange tubes are connected in parallel and are arranged in parallel, and fins are arranged in air circulation gaps between adjacent tubes. It is composed of a flat aluminum tube having a reinforcing wall extending over the header, and both ends of the tube are inserted into tube insertion holes drilled in the header and brazed in a liquid-tight state, and the inside of at least one of the headers is is partitioned in the length direction by the partition means, so that the refrigerant passage constituted by the heat exchange tube group includes at least an inlet side passage group and an outlet side passage group each consisting of a plurality of tubes. The refrigerant is divided into two or more passage groups, and the refrigerant is made to flow in a meandering pattern of two or more passes around each passage group, and the passage cross-sectional area of the outlet side passage group is relative to the inlet side passage group. The tube is set to have the following characteristics: tube width: 6 to 16 mm, tube height: 1.5 to 5 mm, and refrigerant passage height within the tube: 1.0 mm or more, and the corrugated fins are set to have a fin height of It is characterized by having a width of 8 to 16 mm and a fin pitch of 1.6 to 3.2 mm.

Embodiment Next, an embodiment of the present invention will be described along with its operation.

As shown in FIG. 2, the condenser according to the present invention includes a large number of tubes 1 arranged in parallel in the horizontal direction, corrugated fins 2 interposed between adjacent tubes 1, 1, and a group of tubes. A pair of left and right headers 3 and 4 are provided at both ends of the header 3 and 4, which are arranged in parallel and perpendicular thereto.

The tube 1 is made of a flat extruded aluminum material, and has a reinforcing wall 1a extending between the upper and lower walls at the center in the width direction as shown in FIG. It is designed to withstand large internal pressures without any problems. The tube 1 may be of a porous type, such as a so-called harmonica tube. Alternatively, instead of using an extruded material, an electric resistance welded tube may be used, and a reinforcing member corresponding to the reinforcing wall 1a may be inserted and joined inside. The corrugated fin 2 has approximately 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 preferably has a looper cut and raised.

The headers 3 and 4 are made of aluminum pipe material with a circular cross section. These headers 3 and 4 are formed of electric resistance welded tubes having a circular cross section and are made of aluminum plating sheets whose core material is coated with a brazing material on one or both sides. Note that the structure may be made of an extruded aluminum member instead of the electric resistance welded tube. Alternatively, the pipe molded body of the brazing sheet may be used without electrical resistance welding of the abutting portions, and the abutting portions may be brazed at the same time as the tube and header are brazed.

Tube insertion holes 5 are bored at intervals along the length of each header, and both ends of each tube 1 are inserted into the holes and firmly connected by brazing. There is. Further, a refrigerant inlet pipe 6 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 8 is connected to the lower end of the right header 4, and a refrigerant outlet pipe 8 is connected to the upper end of the left header 3. A closing lid piece 9 is attached. Note that 13 and 14 shown in FIG. 1 are upper and lower side plates arranged outside the outermost corrugated fins 2 and 2.

By the way, in the headers 3 and 4 on both sides, there are 1
Two partition plates 10 and 11 are provided, which partition the inside of each header 3 and 3 in the length direction and divide it into two upper and lower chambers. Furthermore, the left partition plate 10 is provided at the center or above the header 3, and the right partition plate 11 is provided at a position about 1/3 of the total length from the bottom end.

By installing the partition plates 10 and 11 as described above,
All refrigerant passages 15 constituted by one group of tubes
(See Figure 11) is divided into three groups of passages: an inlet side passage group A, an outlet side passage group C, and an intermediate passage group B located between them, and the refrigerant is sequentially circulated through each passage group. It is designed to be distributed in a meandering manner. In addition, the intermediate passage group B includes a larger number of tubes, that is, the number of refrigerant passages, than the outlet side passage group C, and its passage cross-sectional area is larger than the passage cross-sectional area of the outlet side passage group C. The passage cross-sectional area of group A is set to be larger than the passage cross-sectional area of intermediate passage group B.

In the above configuration, the refrigerant flowing from the inlet pipe 6 at the upper part of the left header 3, as shown in FIG.
After passing through each tube 1 of the inlet side passage group A and reaching the right header 4, it turns around and flows through each passage of the intermediate passage group B to the left header 3, and then turns around and flows through each of the outlet side passage group C. It flows through the passage to the right header and flows out of the condenser from the outlet pipe 8. While flowing through each passage group, the air exchanges heat with the air flowing in the direction shown by arrow W in FIG. 3 through the air circulation gap including the corrugated fins 2 formed between the tubes 1 and 1. Although the refrigerant passing through the inlet-side passage group A is still in a gasified state with a large volume, the passage cross-sectional area of the inlet-side passage group A is set to be large, so that the heat transfer area is large. The refrigerant is efficiently condensed. The refrigerant passing through the intermediate passage group B is partially liquefied in the inlet side passage group A, so that it is in a gas-liquid mixed state. Therefore, the heat transfer area may be small, but since the passage cross-sectional area of the intermediate passage group B is set smaller than that of the inlet side passage group A, necessary and sufficient heat exchange can be performed. can be passed. When passing through the outlet side passage group C, the refrigerant is already in a liquid state and the volume is small, so the passage cross-sectional area may be small. Since it is set even smaller than that, there is no wasted space to pass the refrigerant. In this way, the passage cross-sectional area of each passage group is reduced from the inlet side passage group A corresponding to the condensing section and further from the intermediate passage group B to the outlet side passage group C corresponding to the supercooling section. Therefore, efficient heat exchange is performed. and header 3,
Since the refrigerant is subjected to a mixing action in the refrigerant 4, it is effectively prevented that the passage becomes liquid-sealed due to being filled with liquid refrigerant.

In the embodiment described above, the case where the passage cross-sectional area is gradually reduced from the entrance passage group A to the exit passage group C is shown, but the passage cross-sectional area of the entrance passage group A and the intermediate passage group B is The area may be kept the same, and only the passage cross-sectional area of the outlet side passage group C may be reduced. In addition, as a means to reduce the passage cross-sectional area of each passage group from the inlet side to the outlet side, we adopted a method of changing the number of tubes 1 included in each passage group, but assuming the number of tubes is the same, the cross-sectional area of each tube itself You may also adopt a method that changes the . Furthermore, the above embodiment shows a three-pass system in which three passage groups are provided and the refrigerant is made to make two U-turns and meander three times; It is also applicable to a two-pass type condenser that makes U-turns only once, and a four-pass or more meandering type condenser in which two or more intermediate passages are formed.

By the way, the pressure loss of the refrigerant flowing through the tube 1 and the air flowing through the tube gap as described above, as well as the heat exchange efficiency, are largely controlled by the design specifications of the tube 1 and the corrugated fins 2. Therefore, in this invention, the tube 1 has a width W of 6 to 16
mm, the height Ht is regulated to 1.5 to 5 mm, and the height Hp of the refrigerant passage 12 in the tube is regulated to 1.0 mm or more.
Hf, that is, the distance between adjacent tubes 1, 1 is 8 to 16
The condition is that the fin pitch Fp is set within the range of 1.6 to 3.2 mm. To explain the reasons for each limitation, the tube width W is restricted to 6 to 16 mm because, as shown in the graph based on the experimental results shown in Figure 7, if it is less than 6 mm, the distance between adjacent tubes 1 and 1 is The width of the corrugated fins 2 interposed in the corrugated fins 2 becomes smaller, and
This is because the number of loopers 2a formed on the fins 2 also decreases, deteriorating the heat exchange performance.
This is because if the width of the fins 2 is made wider than this, the width of the fins 2 will also increase, leading to an increase in pressure loss due to an increase in the flow resistance of the circulating air, and an increase in the weight of the condenser, impairing its practicality. Preferably it is 10 to 14 mm. The reason why the tube height (Ht) is regulated to 1.5 to 5 mm is because, as shown in Figure 8, if the tube height exceeds 5 mm, the pressure loss of the circulating air will increase, whereas if it is less than 1.5 mm, The height Hp of the refrigerant passage inside the tube is 1.0 mm in relation to the tube wall thickness.
This is because it will be difficult to secure more than that. The thickness is preferably 2.5 to 4 mm. The reason why the refrigerant passage height (Hp) in tube 1 is restricted to 1.0 mm or more is because if it is less than 1.0 mm, the pressure loss of the refrigerant will be high.
This is because it causes a decrease in heat exchange efficiency. It is preferably 1.5 to 2.0 mm. On the other hand, the fin height Hf is restricted to 8 to 16 mm because, as shown in Figure 9, if it is less than 8 mm, the pressure loss of the circulating air will increase, whereas if it is 16 mm or more, the total number of fins will be reduced. This is because the fin efficiency decreases and the heat exchange performance deteriorates. It is preferably 8 to 12 mm. Also, the fin pitch Fp is 1.6 to 3.2mm.
The regulations are as shown in Figure 10.
This is because if it is less than 1.6 mm, the louvers 2a will interfere, resulting in a decrease in performance and an increase in air pressure loss, while if it exceeds 3.2 mm, heat exchange performance will deteriorate.

Effect of the invention This invention has the following effects.

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

That is, in the condenser according to the present invention, a large number of heat exchange tubes are arranged in communication between a pair of headers arranged in parallel on the left and right, and the gas introduced from the refrigerant inlet of one of the headers is connected. It is constructed as a so-called multi-flow type heat exchanger that distributes and circulates refrigerant into multiple tubes at the same time. The pressure loss due to refrigerant flow can be greatly reduced. Therefore, it is possible to improve the heat exchange efficiency and reduce the required capacity of the compressor.

(2) It also has excellent pressure resistance and high safety.

That is, as a multi-flow type heat exchanger, there is a type generally known as a conventional radiator. However, this known heat exchanger has many aspects such as the structure of the tank, the joint structure between the tube and the tank, and the structure of the tube.
When used as a condenser that is subjected to a considerable internal pressure, it is difficult to ensure sufficient pressure resistance to withstand the use. However, in this invention, a tube material having a flat cross section and a reinforcing wall between the upper and lower internal walls is used as the heat exchange tube, and the end portion of the tube is used as a communication connection structure between the tube and the header. By being inserted into a hole drilled in the peripheral wall of the header and brazed, it has sufficiently excellent pressure resistance and has sufficient safety and durability without the risk of liquid leakage. It can be done.

(3) It has excellent heat exchange efficiency and can be significantly downsized.

That is, in the condenser of this invention, 1
It is constructed as a horizontal type in which a pair of headers are arranged in parallel on the left and right, and a large number of tubes are arranged horizontally between them, and a partition is provided inside one or both headers. , whereby 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, and the refrigerant is made to make one or more U-turns within the header. In addition, the passage cross-sectional area of the outlet side passage group is relatively smaller than that of the inlet side passage group. Therefore, this allows each of the condensing section and the supercooling section to have a necessary and sufficient passage cross-sectional area that reasonably accommodates the change in the phase state of the refrigerant, that is, the phase change from the gas state to the liquid state. While ensuring that the refrigerant passage has a sufficient length from the inlet to the outlet.
In addition, the refrigerant is subjected to a gas-liquid mixing action when making a U-turn in the vertical header, and is then distributed and introduced into the next horizontal refrigerant passage for further cooling. Therefore, as in conventional serpentine condensers, the liquid phase refrigerant condensed in the refrigerant passage blocks the refrigerant passage especially as it approaches the outlet side, or in the case of a vertical type condenser in which the tubes are arranged vertically. As in the case of heat exchangers, it is possible to effectively prevent the condensed liquid phase refrigerant from accumulating in the lower header due to gravity and blocking the refrigerant passage, resulting in a so-called liquid seal condition. By making the most of the front-to-front area as an effective area for heat exchange, the heat exchange capacity can be significantly improved.

In addition, since a plurality of tubes are arranged in parallel, corrugated fins are arranged between adjacent tubes, and both ends of each tube are connected to the hollow header, the tubes are There are no restrictions on the selection of the width, tube spacing, ie, fin height, etc., and any design specification is possible. With this configuration,
Regarding the tubes and corrugated fins that most affect the performance of the condenser, the tube width, tube height, refrigerant passage height in the tube, fin height, and fin pitch are set to the most appropriate ranges, so the weight It is possible to provide a condenser that can be operated in the most efficient and optimal state in which the pressure loss of the refrigerant and circulating air and heat exchange performance are in harmony without causing any increase in heat exchange performance. Therefore, it has excellent heat exchange efficiency, and as a result, the overall size of the condenser can be reduced, making it ideal as a condenser for vehicles, especially in narrow spaces. The amount of CFC refrigerant, which has become a social problem as a pollution factor, can be significantly reduced by more than 30% compared to the conventional serpentine condenser.

(4) Easy to manufacture and has excellent productivity.

That is, the condenser of the present invention can be assembled and manufactured by, for example, first inserting both ends of the tube into the holes of the header to form a frame-shaped skeleton, and then inserting fins between adjacent tubes to temporarily assemble the whole. Alternatively, it can be easily done by arranging tubes and fins alternately, combining them with headers to form a temporary assembly state, and then brazing them all at once in a furnace, improving productivity and resulting in Manufacturing costs can be reduced.

[Brief explanation of drawings]

The drawings show an embodiment of the invention, and FIG. 1 is an overall front view of the condenser, FIG. 2 is a plan view, and FIG.
Fig. 3 is a sectional view taken along the - line in Fig. 1, Fig. 4 is a perspective view of the main parts with the constituent members separated, and Fig. 5
The figure is an enlarged cross-sectional view seen from the same direction as Figure 3.
The figure is an enlarged front view showing the corrugated fins and tubes, Figure 7 is a graph showing the relationship between changes in tube width and changes in heat transfer rate in the condenser shown in Figures 1 to 6, and Figure 8 9 is a graph showing the relationship between the change in tube height and the change in pressure loss on the air side, FIG. The figure is also a graph showing the relationship between changes in exchange heat amount and air pressure loss with respect to changes in fin pitch, and FIG. 11 is a refrigerant circuit diagram of the condenser shown in FIG. 1. 1...Tube, 2...Colgate Finn,
3, 4... Header, 15... Refrigerant passage, A...
Inlet side passage group, B...middle passage group, C...outlet side passage group, W...tube width, Ht...tube height, Hp...refrigerant passage height, Hf...fin height,
Fp……fin pitch.

Claims (1)

[Scope of Claims] 1. A pair of aluminum cylindrical headers arranged parallel to each other on the left and right with an interval between them, and a plurality of aluminum cylindrical headers arranged horizontally and in parallel with both ends connected to the headers, respectively. A flat aluminum tube having a flat heat exchange tube and fins disposed in an air flow gap between adjacent tubes, the tube having a flat cross section and a reinforcing wall extending between the upper and lower walls. Both ends of the tube are inserted into tube insertion holes drilled in the header and brazed in a liquid-tight state, and the inside of at least one of the headers is partitioned at a predetermined position in the length direction. The refrigerant passages constituted by the heat exchange tube group are partitioned by the means, so that the refrigerant passages constituted by the heat exchange tube group are at least two passages each including an inlet side passage group and an outlet side passage group each consisting of a plurality of heat exchange tubes. The refrigerant is divided into groups, and the refrigerant is made to flow in a meandering pattern of two or more passes around each group of passages, and the passage cross-sectional area of the passage group on the outlet side is reduced relative to the group of passages on the inlet side. In addition, the tube is set to have: tube width: 6 to 16 mm, tube height: 1.5 to 5 mm, and refrigerant passage height in the tube: 1.0 mm or more, and the corrugated fins are set to have a fin height of 8 to 16 mm. Fin pitch: A condenser characterized by being set at 1.6 to 3.2 mm.