JPH07208888A - Tube for heat exchanger for air conditioner and heat exchanger for air conditioner - Google Patents

Abstract

PURPOSE:To improve heat-exchanging capability by heightening the height of protruding strips as high as possible in a tube for a heat exchanger for an air conditioner, through which a refrigerant in a two-phase state of vapor and liquid flows and which has multiple fine protruding strips pressed and formed on the inner face thereof. CONSTITUTION:A groove 5 having a width narrower than that of protruding strips 2 is pressed and formed on the center line of each of the protruding strips 2, which are provided on an inner face side of a band plate, and on the outer face side of the band plate at the same time that the protruding strips 2 are formed. Accordingly, by forming the grooves on an outer face side of a tube, the material corresponding to the portion of each groove is moved to the protruding strip side, and the height of each protruding strip can be heightened by that which corresponds thereto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tube of an air-conditioning heat exchanger through which a gas-liquid two-phase refrigerant flows, and more particularly to a grooved welded copper tube having a large number of fine grooves formed by pressing on the inner surface of the tube. .

[0002]

2. Description of the Related Art A conventional grooved welded copper tube has a diameter of 7 mm.
It is a tube with a joint of about 10 mm to 0.3 mm
A thin copper strip with a thickness of about 0.4 mm is formed by rolling, etc. on only one surface to form a number of parallel fine protrusions with a chevron cross section, and then the strip is rounded into a circular cross section, and both edges are formed. The parts are electric welded. The ridge height of this grooved welded copper tube was about 0.15 mm to 0.16 mm.

[0003]

In such a grooved copper tube, when a refrigerant that changes into a gas-liquid two-phase flows, the liquid phase or the gas-liquid mixed phase comes into contact with the fine ridges and the contact surface thereof. As a result, the flow of gas and liquid is agitated to facilitate the phase change from the liquid phase to the gas phase, at which time the heat of evaporation is taken from the inner wall and the air flow flowing to the outer surface of the tube is efficiently cooled. . However, the height of the ridges of the grooved tube was about 0.15 mm to 0.16 mm, and the effect of enlarging the surface area and the effect of stirring the refrigerant were not great. In order to increase the height of this ridge, the plate pressure of the tube must be increased accordingly, and increasing the plate pressure of the tube hinders weight reduction and uses many copper materials. However, there was a drawback in that it was not economical.
Therefore, an object of the present invention is to provide a tube capable of increasing the height of the ridges formed on the inner surface without increasing the plate pressure of the entire tube, and the following configuration is adopted to achieve the object.

[0004]

In the tube of the present invention, a thin metallic strip 1 is provided with a large number of parallel fine protrusions 2 having a chevron cross section on one surface thereof, and a fine corrugation 3 is pressed. The corrugations 3 are formed on the inner surface and both edges in the width direction are continuously liquid-tightly joined. The ridges 2 are formed on the other surface of the strip 1 on the center lines of the ridges 2.
It is characterized in that the concave groove 5 having a width equal to or smaller than the width is formed by pressing at the same time when the ridge 2 is formed. Further, in the heat exchanger for air conditioning of the present invention, the tubes 4 are inserted into the tube insertion holes 7 of the multiple tube plates 6 arranged in parallel, and the recessed grooves 5 formed on the outer surfaces of the tubes are the inner surfaces of the tube insertion holes 7. It is configured to form a minute space between and.

[0005]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a plan view showing a developed state of the tube of the present invention, FIG. 2 is an enlarged cross-sectional view of the tube, FIG. 3 is a partially enlarged view thereof, and FIG. 4 is a developed tube of a second embodiment of the present invention. 5 and 5 are development views of the tube of the third embodiment, and FIG.
FIG. 7 is a vertical cross-sectional view of the tube of the present invention in use.
FIG. 7 is an enlarged view of a cross section taken along line VII-VII of FIG. 6. The tube of this example is used for an air conditioner heat exchanger through which a gas-liquid two-phase refrigerant flows, and the cross-section has an outer diameter of 7 mm to
It is about 10 mm. The plate pressure of this tube is 0.3
Using a strip-shaped copper plate having a size of mm to 0.5 mm, the widthwise both edges 9 are left by upper and lower roll materials, and as shown in FIG. . That is, the angle formed by each ridge 2 with respect to the axis is 18 degrees. The cross section of the ridge is formed in a trapezoidal shape, and the height of the ridge is 0.18 mm to 0.25 mm. And
As shown in FIG. 3, the depth of the concave groove 5 formed on the outer surface of the tube is 0.03 mm to 0.05 mm, the width of which is smaller than the width of the ridge 2, and the center line of the groove is the ridge. It is aligned with the center line of 2. That is, the bead angle is the same as that of the ridge 2.

Such a strip is manufactured by a pair of upper and lower forming rolls. One forming roll forms a large number of fine ridges, and the other forming roll forms a large number of concave grooves. The strip plate is sandwiched between the pair of forming rolls, and the upper and lower forming rolls synchronously press and form the copper strip plate. The bead angles and shapes of the convex stripes 2 and the concave grooves 5 may be formed as shown in FIGS. In this way, a large number of convex strips 2 and concave grooves 5 are pressed and formed on both sides of the copper strip, and a circular pipe is formed in the next step, and both edges 9 thereof are liquid-tightly joined by electric welding. It The method for forming the circular tube and the method for welding are omitted because they are known.

The wall thickness of the tube of this embodiment after molding is about 0.25 mm to 0.3 mm at the thin portion outside the ridge. This tube is inserted through the insertion holes 7 of a large number of plate fins 6 arranged in parallel as shown in FIGS. The insertion hole 7 is formed by slightly raising the edge of the plate fin 6 to form a burring portion 8. An enlarged cross-sectional view of the plate fin 6 and the tube 4 is as shown in FIG. 7, and most of the tube 4 and the inner peripheral edge of the insertion hole 7 of the plate fin 6 are in contact with each other, but the concave groove 5 of the tube 4 is A space is formed in the part. 6 and 7
The heat exchanger core in which the plate fins and the tubes are assembled as described above is to be cleaned next, but the presence of the concave groove 5 causes the cleaning agent or cleaning water to be a space between the concave groove 5 and the insertion hole 7. Therefore, the cleaning effect is high. When used as a heat exchanger for air conditioning, since there are many concave grooves 5 on the outer surface of the tube 4, the tube 4
The heat dissipation of the outer surface is improved.

[0008]

The tube of the heat exchanger for air conditioning of the present invention is
If a metal strip having the same thickness as that of the conventional strip is used, the height of the ridges 2 formed on the inner surface of the tube can be made higher than that of the conventional strip, and the stirring effect and contact of the fluid flowing inside can be achieved. This has the effect of increasing the area and promoting heat exchange.
That is, when the fine ridges 2 are formed on the inner surface of the thin metal strip 1 by pressure molding, the concave grooves 5 are formed by pressing from the outer surface to the positions aligned with the ridges 2, thereby maintaining the strength. The height of the ridge 2 can be increased. because,
When the ridge 2 is formed by pressing, the material portion of the concave groove 5 on the outer surface side is plastically deformed to the ridge 2 side and biased, and as a result, the height of the ridge 2 can be increased.

According to the second aspect of the invention, since a minute space is formed between the insertion hole 7 of the tube plate 6 and the groove 5 formed on the outer surface of the tube 4, the heat exchanger is manufactured. In this case, the outer surface of the tube 4 and the inner surface of the insertion hole 7 can be easily washed, and the heat exchange performance is improved by eliminating the oil film and the like. At the same time, the presence of the large number of concave grooves 5 formed on the outer surface of the tube enlarges the contact surface with the air flowing through the outer surface of the tube and agitates the air flow to improve the heat transfer property on the air side.

[Brief description of drawings]

FIG. 1 is a development view of a tube of the present invention.

FIG. 2 is an enlarged cross-sectional view of the tube.

FIG. 3 is a partially enlarged view of the tube.

FIG. 4 is a development view of a second embodiment of the tube of the present invention.

FIG. 5 is a development view of a third embodiment of the tube of the present invention.

FIG. 6 is a vertical cross-sectional view showing a usage state of the tube of the present invention.

FIG. 7 is a partially enlarged view of a cross section taken along the line VII-VII of FIG.

[Explanation of symbols]

 1 band plate 2 convex stripe 3 corrugated 4 tube 5 concave groove 6 plate fin 7 insertion hole 8 burring portion 9 edge

Claims (2)

[Claims] 1. A thin metal strip 1 is provided with a large number of parallel ridges 2 each having a fine chevron cross-section on one surface thereof to be pressed into a fine corrugation 3, and the corrugation 3 is located on the inner surface. In the tube 4 of the air-conditioning heat exchanger in which both edges in the width direction are continuously joined, on the other hand, on the center line of each of the ridges 2 and the width of the ridge 2 or less on the other surface of the strip 1. A tube for an air-conditioning heat exchanger, characterized in that a concave groove (5) having a width is formed by pressing at the same time when the ridge (2) is formed. 2. The tube 4 according to claim 1 is inserted into the tube insertion holes 7 of a large number of juxtaposed tube plates 6, and the concave groove 5 formed on the outer surface of the tube is provided between the tube insertion hole 7 and the inner surface of the tube insertion hole 7. An air-conditioning heat exchanger configured to form a minute space.