KR20030027610A - Manufacturing method of tube for heat exchanger - Google Patents

Abstract

PURPOSE: A manufacturing method of tube for heat exchanger is provided to improve productivity by assembling a plural tube rows in a single process in a heat exchanger for carbon dioxide and manufacturing the tube rows easily with an existing facility. CONSTITUTION: The manufacturing method of an integral tube(50) for heat exchanger comprises extrusion step of integrally forming at least two or more tube bodies(52,54) in which a refrigerant pipe is longitudinally formed as a continuous line and a bridge(56) for connecting the tube bodies; drilling step of forming penetration holes(58) on the bridge in a length direction of the bridge with spaced apart from each other in a certain distance; cutting step of cutting the integral tube(50) to a certain length from a part where the penetration holes are formed; and a post-processing step of processing both end parts of the cut integral tube, wherein both end parts of the tube bodies are processed in a shape corresponding to shape of tube holes of header pipes(10,20) for heat exchanger into which the tube bodies are inserted in the post-processing step, and wherein the bridge(56) is thinner than the tube bodies(52,54).

Description

Manufacturing method of tube for heat exchanger

The present invention relates to a tube of a heat exchanger, and more particularly, to a tube of a heat exchanger using a fluid having a supercritical pressure refrigeration cycle, such as carbon dioxide as a refrigerant, a method for manufacturing the same, and a heat exchanger having the tube. .

In general, a heat exchanger is a device in which a high temperature fluid and a low temperature fluid transfer heat from a high temperature to a low temperature through a heat exchanger wall to perform heat exchange. Although HFC refrigerants have been mainly used as an operating medium of air conditioner systems having such heat exchangers, such HFC refrigerants are recognized as one of the main factors of global warming, and regulations on their use are gradually being expanded. Under these circumstances, research on carbon dioxide refrigerants as a next generation refrigerant to replace HFC refrigerants has been actively conducted.

Carbon dioxide, the representative of such next-generation refrigerants, corresponds to about one-third of R134a, a global warming index (GWP), is a representative HFC refrigerant. In addition, it has the following advantages as a refrigerant. In other words, the compression ratio is excellent due to the low operating compression ratio, and the heat transfer performance is very good so that the temperature difference between the inlet temperature of the secondary fluid air and the outlet temperature of the refrigerant can be much smaller than that of the conventional refrigerant. This advantage can be used to extract heat at low outside temperatures in winter, so it can be applied to heat pumps that perform cooling in summer and heat in winter.

In addition, since carbon dioxide has a volume cooling capacity (evaporative latent heat x gas density) of 7 to 8 times that of the conventional refrigerant R134a, the capacity of the compressor can be greatly reduced, and the surface tension is small, so the boiling heat transfer is excellent, and the static pressure specific heat This large and low viscosity has excellent heat transfer performance and therefore has excellent thermodynamic properties as a refrigerant. In addition, when looking at the side of the refrigeration cycle operating pressure is 6 ~ 8 times (about 100 ~ 130 bar) higher than the conventional, the loss due to the pressure drop of the refrigerant in the heat exchanger is relatively small compared to the conventional refrigerant bar, It is possible to use heat exchanger tubes with microtubes which are known to have great pressure drop but good heat transfer performance.

On the other hand, a heat exchanger using carbon dioxide as a refrigerant can be classified into two types, namely, a multi-pass method and a multi-slab method.

The multi-pass method increases the number of passes of the refrigerant flowing through the tube through a plurality of baffles in the header tank. The distribution of the refrigerant in the heat exchanger is good, but carbon dioxide, a refrigerant when the refrigerant is cooled, is in the heat exchanger. There is no condensation at, which leads to a continuous drop in temperature, resulting in a severe temperature deviation across the heat exchanger, resulting in the heat flow itself along the surface of the heat exchanger through tubes and fins. This heat flow prevents the refrigerant from exchanging heat with the external inlet air and naturally reduces the heat exchange performance.

In the multi slab method, a plurality of rows of tubes are arranged so that the refrigerant exchanges heat as the tube passes through the heat of the tube, which can block heat flow as in the multi-pass method. More effective.

However, in such a multi-slap heat exchanger, since the independent refrigerant passages of the heat exchanger header tanks must be communicated with each other separately, they are connected to separate tubes.

Therefore, in order to manufacture a heat exchanger having a separate tube row, there is a problem that a lot of work is required to assemble it.

Therefore, the necessity of manufacturing them in one piece has been raised, and a method that can be easily manufactured using the existing manufacturing equipment of the condenser tube needs to be devised.

The present invention is designed to solve the above problems, while operating under high pressure, such as carbon dioxide, heat transfer using a fluid having excellent heat transfer performance as a refrigerant while maintaining the thermal characteristics of the refrigerant, at the same time manufacturing equipment of the existing condenser It is an object of the present invention to provide a method for manufacturing a tube for a heat exchanger that can be manufactured without greatly changing the temperature.

1 is a perspective view of a heat exchanger with a tube made according to the present invention.

2 is a partial perspective view of a tube for a heat exchanger produced by the present invention.

3 is a cross-sectional view of a heat exchanger with a tube made according to the present invention.

4a to 4d is a view showing the manufacturing process of the tube for the heat exchanger according to an embodiment of the present invention.

※ Explanation of code for main part of drawing

10: first header pipe 12, 14: first and second compartment

20: second header pipe 22, 24: 3rd and 4th compartment

11, 21: Cap 30: refrigerant inlet pipe

40: refrigerant outlet tube 50: heat dissipation tube

52: first tube 54: second tube

56: bridge 58: through hole

60: heat sink fin

In order to achieve the above object, the present invention is an extrusion step of integrally forming at least two tube body and the bridge connecting the tube body formed with a refrigerant flow tube in the longitudinal direction therein in a continuous line; A perforating step of forming a through hole at a predetermined interval along the longitudinal direction of the bridge, a cutting step of cutting the integral tube to a predetermined length and cutting at a portion where the through hole is formed, and both ends of the cut integral tube It provides a method for producing an integrated tube for a heat exchanger, characterized in that it comprises a post-processing step of processing.

According to another feature of the invention, the post-processing step may be to process both ends of the tube body in a shape corresponding to the shape of the tube hole of the heat exchanger header pipe is inserted into the tube body, in the integral tube formed as described above The bridge may be formed thinner than the tube body.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, the structure of the heat exchanger tube manufactured by the present invention will be described.

1 is a perspective view showing the structure of a heat exchanger for carbon dioxide employing an integral tube produced by the present invention, Figure 2 is a perspective view showing an integral tube manufactured by the present invention, Figure 3 is as shown in FIG. It is a figure which shows the state in which the integrated tube manufactured by this invention was mounted in the said heat exchanger for carbon dioxide.

Referring to the structure of the tube manufactured by the present invention with reference to Figure 2, first, the tube for the heat exchanger manufactured by the present invention each of the tubes 52, 54 each having a micro-tube 51 so that the refrigerant flows therein ) Is connected by the bridge 56. The direction of the refrigerant flowing through each of the tubes 52 and 54 is reversed. Accordingly, the temperature of the refrigerant flowing through each of the tubes 52 and 54 may be different.

On the other hand, the bridge 56 is formed with a plurality of through holes 58 along the longitudinal direction of the tube 52, 54, the through hole 58 is a temperature difference between the tubes 52, 54 This is to prevent heat exchange from occurring. The end of the tube is inserted into a tube hole formed in the header pipe of the heat exchanger, and the inner portions 59 of both ends of the tube to be inserted are formed to correspond to the shape of the tube hole of the header pipe.

The tube of this structure can be mounted to a heat exchanger as shown in FIG. The heat exchanger shown in FIG. 1 has a first header pipe 10 having first and second compartments 12 and 14 that are independent of each other, and third and fourth compartments arranged in parallel with and communicating with the first header pipe. A second header pipe 20 having (22) and (24) is provided. The tube 50 produced by the present invention communicates the compartments of the header pipes 10 and 20 individually, the first compartment 12 of the first header pipe 10 and the second header pipe. Tube rows consisting of the first tubes 52 communicate the third compartment 22 of the 20 with each other, and the second compartment 14 of the first header pipe 10 and the first of the second header pipe 20 The two compartments 24 communicate with each other through a series of tubes consisting of a second tube 54. The ends of each header pipe 10, 20 are sealed with caps 11, 21. In addition, a coolant inlet pipe 30 through which a coolant flows is installed in the first compartment 12 of the first header pipe 10, and a coolant after the heat exchange has exited from the lower end of the second compartment 14. Outflow pipe 40 is installed. A heat dissipation fin 60 is installed between each tube to improve heat exchange efficiency.

The heat exchanger having such a structure performs heat exchange primarily through the refrigerant flowed from the refrigerant inlet pipe 30 through the tube rows formed by the first tube 52 through the first compartment 12. In addition, the refrigerant flows from the second header tank 20 to the fourth compartment 24 through the communication hole 25, passing through the tube rows formed of the second tube 54, as shown in FIG. 3. Second heat exchange will be performed.

Since separate heat exchange is performed for each tube row in the heat exchanger, each tube is separately connected to the compartment of each header pipe, but this causes a problem of complicated assembly process. Therefore, using the tube connected by the bridge 56 as in the present invention, not only can reduce the labor, but also makes the assembly process much simpler. At this time, since the temperatures of the refrigerant performing the first heat exchange and the second heat exchange are different from each other, in order to prevent heat exchange through the bridge 56, the through holes 58 are formed in the bridge 56 at predetermined intervals. To form.

Next, a method of manufacturing a tube for a heat exchanger having such a configuration will be described.

First, as shown in FIG. 4A, a first tube 52 having a plurality of microtubes 51 and a second tube 54, and a bridge 56 connecting them are continuously connected to allow a refrigerant to flow therein. It is formed integrally by extrusion into a line. At this time, the bridge 56 is preferably formed to be thinner than the first and second tubes 52, 54. This is to reduce heat exchange between the first and second tubes 52 and 54.

In the bridge 56 of the tube thus formed, the through holes 58 are drilled at predetermined intervals as shown in FIG. When cutting, both ends should be positioned in the through hole 58. This is to allow the tube to be inserted into the header pipe.

4c shows the end of the cut tube, as shown in the figure, both sides of the through hole 58 formed in the bridge 56 do not exactly coincide with the sides of the first and second tubes 52, 54. Will not. Insertion into the tube hole of the header pipe in such a state may cause a stamping at the insertion, which may cause a defect in the pipe and cause a brazing failure. Therefore, there is a need for a process for smoothing both ends of the tube by post processing. As shown in the figure, when the shape of the tube hole is elliptical, as shown in Figure 4c it should be rounded the end by the rounding machine 70, 72. In particular, the inner side end 59 of the tube should be smoothed as shown in FIG. 4D by rounding.

The tube described above has been described with a heat exchanger having two tube rows for performing a separate heat exchange, but can also be applied to a multi-slab type heat exchanger having a plurality of tube rows.

According to the present invention as described above, in the heat exchanger for carbon dioxide, a plurality of tube trains can be assembled in a single process, and the tube trains can be easily manufactured even with existing equipment, thereby improving productivity.

Although the present invention has been described with reference to one embodiment shown in the accompanying drawings, it will be understood that various modifications and other embodiments are possible to those skilled in the art. Therefore, the protection scope of the present invention will be defined by the appended claims.

Claims (3)

An extrusion step of integrally forming at least two tube bodies having a refrigerant flow tube formed therein in a continuous line and a bridge connecting the tube bodies; A perforation step of forming a through hole in the bridge at a predetermined interval along its longitudinal direction; A cutting step of cutting the unitary tube to a predetermined length and cutting at a portion where the through hole is formed; And And a post-processing step of processing both ends of the cut integral tube. The method of claim 1, In the post-processing step, the both ends of the tube body are processed into a shape corresponding to the shape of the tube hole of the heat exchanger header pipe into which the tube body is inserted. The method according to claim 1 or 2, The bridge is a method of manufacturing a tube for a heat exchanger, characterized in that to be formed thinner than the tube body in the step.