JPH04110597A - Heat transfer pipe of heat exchanger - Google Patents

Abstract

PURPOSE:To improve a heat transfer efficiency by a method wherein a foamed member of copper or copper alloy is deposited on an inner surface of a raw pipe of copper or copper alloy. CONSTITUTION:A foamed member 2 of copper or copper alloy with a thickness of 0.5 to 2mm, for example, is closely contacted to and fixed to an inner surface of a raw pipe 1 of copper or copper alloy over its entire length. The foamed member 2 is a cell structure. Since an inner surface of the raw pipe 1 is covered by the cell foamed member 2, a contact area with thermal medium can be increased, a heat transfer efficiency of the heat transfer pipe for the heat exchanger can be remarkably increased and a heat exchanging performance can be remarkably improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat exchanger tube for a heat exchanger used in an air conditioning refrigerator or the like.

[Prior Art] Conventionally, this type of heat exchanger tube is made of copper or copper alloy, which has high heat transfer efficiency. In this heat transfer tube for a heat exchanger, heat exchange is performed by evaporation or boiling of the heat medium flowing through the tube, so the following improvements are effective in increasing the heat transfer efficiency.

■Increase the inner surface area of the pipe.

■Activate nucleate boiling and condensation on the inner surface of the tube.

■Make it easier for the heat medium to spread over the entire surface of the tube due to capillary action, etc.

■Making turbulence more likely.

On the other hand, conventional heat exchanger tubes, especially smooth tubes with smooth tube inner surfaces, cannot satisfy the above requirements.

Therefore, in recent years, heat transfer tubes (inner grooved tubes) having spiral grooves formed on the inner surface have been proposed in order to expand the inner surface area of the tube and increase the turbulence of the heat medium flow. Also,
This internally grooved tube is generally manufactured by forming a groove on one surface of a plate material by rolling, and then forming the plate material with the one surface inside.

[Problems to be Solved by the Invention] However, in the above-mentioned internally grooved tube, due to its manufacturing technology, the processing speed of rolling is slow and the number of grooves, twist angle, etc. are limited, so it is difficult to use for heat exchangers. There is a problem that the performance of the heat exchanger tube cannot be improved to the desired level.

The present invention has been made in view of such problems, and includes:
It is an object of the present invention to provide a heat exchanger tube for a heat exchanger that can further improve heat transfer efficiency.

[Means for Solving the Problems] A heat exchanger tube for a heat exchanger according to the present invention is characterized in that a foam made of copper or a copper alloy is adhered to the inner surface of a base tube made of copper or a copper alloy.

[Function] In the present invention, a foamed body of copper or copper alloy is adhered to the inner surface of a raw tube made of copper or copper alloy.

Since this foam has a mesh-like or cell-like three-dimensional skeletal structure, the surface area inside the tube that comes into contact with the heat transfer medium is extremely large, and turbulence occurs in the heat transfer medium flowing through the tube. It's easy to do. Further, the foam has fine and continuous voids, and voids are also formed inside the skeleton itself. For this reason, the capillary phenomenon caused by these voids makes it easier for the liquefied heat medium to spread over the entire surface of the tube, making it extremely efficient in transporting the heat medium compared to conventional tubes with internal grooves that have various internal fin shapes. expensive. Furthermore, the foam has fine undulations and its surface activity is higher than that of a smooth tube.

Therefore, the foam acts as a boiling nucleus or a condensation nucleus and promotes boiling and condensation of the heat transfer medium.

Therefore, the heat exchanger tube for a heat exchanger according to the present invention can further increase the heat transfer efficiency compared to the conventional tube, and can significantly improve the heat exchange performance.

In addition, in the present invention, grooves may be formed on the inner surface of the raw tube in the same manner as in conventional inner-grooved tubes. In this case as well, the same effect as when the inner surface of the tube is smooth can be obtained.

[Embodiments] Next, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a partially cutaway perspective view showing a heat exchanger tube for a heat exchanger according to an embodiment of the present invention.

The raw tube 1 made of copper or copper alloy has a smooth inner surface. A foam 2 made of copper or copper alloy and having a thickness of, for example, 0.5 to 21 mm is tightly fixed to the inner surface of the raw pipe 1 over the entire length of the raw pipe 1. This foam 2
As shown in the partially enlarged view of FIG. 2, it has a cell-like structure. Further, the foam 2 made of copper or copper alloy is relatively inexpensive and easily available.

Next, a method for manufacturing the above-mentioned heat exchanger tube will be explained.

First, the diameter is slightly smaller than the inner diameter of the raw pipe 1 8
After wrapping a pipe-shaped foam 2 around the keyaki, the foam 2 is inserted into the base pipe 1 together with the eight rods. Thereafter, the eight rods are extracted from the inside of the raw tube 1.

Next, the raw pipe 1 and the foam 2 are formed by the method shown below.
and are closely fixed to each other.

■Pultrusion method By inserting a fixed plug or a floating plug inside the foam 2, or by passing the raw pipe 1 through a drawing die and reducing its diameter without inserting anything, the raw pipe 1 and the foam 2 can be separated. are closely fixed to each other.

■ Roll pressure method By narrowing down the outer diameter of the raw tube 1 using a pair of forming rolls with a circular caliber or a pair of rolling rolls, the outer diameter of the raw tube 1 and the foam 2 are mutually bonded. Fix it tightly.

■ After injecting water-soluble flux into the brazing material tube 1 and inserting the solder wire, the material tube is heated using an induction heater or bright annealing furnace while introducing an inert gas or reducing gas into the material tube 1. 1 is heated to braze and join the raw pipe 1 and the foam 2 to each other.

■ Plating method After injecting the plating liquid into the raw tube 1 and inserting the anode, plating the inner surface of the raw tube 1 using the raw tube 1 as the cathode, the raw tube 1 and the foam 2 are mutually bonded. Join with plating. In this case, although the cells of the foam 2 are slightly crushed by plating, it is possible to prevent the foam 2 from peeling off from the inner surface of the raw pipe 1 and falling out from inside the raw pipe 1.

In this way, the raw pipe 1 and the foam 2 can be reliably fixed to each other by the methods shown in (1) to (3) or other methods.

In the heat exchanger tube configured as described above, since the cellular foam 2 is adhered to the inner surface of the raw tube 1,
The contact area with the heat medium can be significantly increased.

Furthermore, the cell size of the foam 2 can be appropriately selected, as shown in the partially enlarged views of FIGS. 3(a) and 3(b). That is, the cells can be formed relatively coarsely, as in the foam 2a of FIG. 3(a), or the cells can be formed relatively finely, as in the foam 2b of FIG. 3(b). I can do it. In this way, fine cells rich in capillary force can be formed as needed, so the capillary action of the cells makes it easier for the liquefied heat medium to spread throughout the tube, further increasing the transport efficiency of the heat medium. be able to.

Furthermore, since the foam 2 is rich in fine undulations, its surface activity is higher than that of a smooth tube or a tube with internal grooves. Therefore, the foam 2 acts as a boiling nucleus or a condensation nucleus, and can promote boiling and condensation of the heat medium flowing through the pipe.

Furthermore, since the foam 2 is previously formed into a vibrator shape and then adhered to the inner surface of the raw pipe 1, it has a large turbulence generating effect on the heat medium flowing inside the pipe.

Therefore, according to this embodiment, the heat transfer efficiency of the heat exchanger tube for a heat exchanger can be significantly increased, and the heat exchange performance thereof can be significantly improved.

In this embodiment, a tube with a smooth inner surface is used as the raw tube 1, but a tube with inner grooves may be used instead of such a smooth tube.

In this case, the heat transfer efficiency can be further improved than in the above embodiment.

[Effects of the Invention] As explained above, according to the present invention, since the copper or copper alloy foam is adhered to the inner surface of the raw pipe made of copper or copper alloy, the surface area inside the pipe is extremely large, and Turbulence is likely to occur in the heat medium flowing through the pipe. Further, due to the capillary phenomenon of the foam, the heat medium easily spreads over the entire surface of the tube, and the transport efficiency of the heat medium is extremely high. Furthermore, the foam has high surface activity and acts as boiling nuclei or condensation nuclei, thereby promoting boiling and condensation of the heat transfer medium.

Therefore, the heat exchanger tube for a heat exchanger according to the present invention can significantly increase the heat transfer efficiency compared to the conventional tube, and can improve the heat exchange performance.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing a heat exchanger tube for a heat exchanger according to an embodiment of the present invention, and FIGS. 2 and 3 are partially enlarged views of FIG. 1. 1; Raw pipe, 2r 2a, 2b; Foam Figure 1

Claims (2)

[Claims] (1) A heat exchanger tube for a heat exchanger, characterized in that a foam made of copper or copper alloy is adhered to the inner surface of a raw tube made of copper or copper alloy. (2) The heat exchanger tube for a heat exchanger according to claim 1, wherein the raw tube has grooves formed on its inner surface.