JPS5842787Y2 - Heat exchanger tube with fins - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a finned heat exchanger tube of an air-cooled heat exchanger used in an outdoor unit of an air conditioner or the like.

FIG. 1 shows an outdoor unit of an air conditioner.

In this outdoor unit 1, a compressor 3 is disposed in the lower part of the casing 2, and a virtual cylindrical heat exchanger 4 that acts as a condenser is disposed in the upper part. 6 and fan 7 are fixed.

By the air A flowing from the suction port 8 formed on the side of the casing 2 to the air outlet 9 above the casing 2,
The heat medium pumped from the compressor 3 into the finned heat transfer tubes 10 of the heat exchanger 4 is cooled and condensed.

Conventionally, the heat exchanger tubes 10 with fins constituting the heat exchanger 4 have been produced by cutting off both ends of the band-shaped fins 13 except for the joint portion 14 with the heat exchanger tube 11, as shown in FIGS. 2 and 3. to form a large number of fin pieces 12.12.
... are wrapped around the outer periphery of the heat exchanger tube 11 so as to protrude radially and are fixed with solder, and these fin pieces 12, 12
. . . promotes cooling of the heat medium flowing inside the heat transfer tube 11.

Generally, when air flows along the side of a fin, the fin surface heat transfer coefficient α is highest at the front edge of the fin F, where the wind first hits, as shown in Figure 4, and as the fin width X increases. Indeed, it gradually decreases as the boundary layer develops.

Therefore, the average heat transfer coefficient of the fin surface increases as the fin width X decreases.

From this fact, it can be seen that in the case of the finned heat exchanger tube 10, the smaller the width d of the fin pieces 12, the higher the fin surface average heat transfer coefficient.

However, if the width d of the fin piece 12 is made smaller,
The root portion 12a of the fin piece 12 (which is bent at a substantially right angle) also becomes smaller, making it more likely to break or tear due to corrosion, causing problems in terms of strength and corrosion resistance.

The present invention forms a fin piece divided into two at the tip of each fin piece of a band-shaped fin, and bends the base of at least one of the fin pieces in a direction substantially perpendicular to the width direction of the fin piece. The purpose is to improve the fin surface average heat transfer coefficient without reducing the strength and corrosion resistance at the base of the piece.

Hereinafter, a finned heat exchanger tube according to an embodiment of the present invention will be explained with reference to FIGS. 5 to 8.

In the embodiment shown in FIGS. 5 to 7, the band-shaped fins 13 are cut at both ends along score lines 15, leaving a joint 14 with the heat exchanger tube 11, and have a large number of fin pieces 12, 12, . . .
..., and each fin piece 12 is cut into a narrow fin piece 1 by a cut line 16 that vertically divides the fin piece 12 into two from the tip, leaving a part close to the root part 12a.
7.17 is formed, and furthermore, from the base portions 17a, 17a of both fin pieces 17.17, the direction is substantially perpendicular to the width direction of the fin piece 12, and both fin pieces 17.17 are parallel to each other. The bent fin pieces 17 and 17 are bent in opposite directions so that the fin pieces 12a and 12
They are formed so that the spacing is equal to the spacing of a.

Each fin piece 1 is attached to the outer periphery of the heat transfer tube 11.
The heat exchanger tube 10 with fins is constructed by winding the tubes 2 in a spiral manner so as to protrude radially and then soldering them.

To explain the action of the illustrated finned heat exchanger tube, air A is sucked in from the suction port 8 by the rotation of the fan 7 (see FIG. ), each fin piece 17 acts like an independent fin, as shown in FIG.
Since the width is d, the fin surface average heat transfer coefficient is significantly improved compared to the conventional example.

Also, compared to the conventional example, there are more cut surfaces, the width d' of the fin pieces 17 is smaller, and the distance a between the fin pieces on the same plane is about twice that of the conventional example, so the air flow A is reduced. The effect of the boundary layer on the upstream fin piece relative to the downstream fin piece is reduced, and the fin surface heat transfer coefficient increases (approx. 20% improvement according to experiments).

FIG. 8 shows another embodiment of the present invention.

In this case, one of the fin pieces 17.17 is not bent, and the base 17a of the other fin piece 17 is attached to the fin piece 1.
In a direction substantially perpendicular to the width direction of 2, both fin pieces 17.17
are bent so that they are parallel to each other and the distance between both fin pieces 17 and 17 is equal to the distance between the base portions 12 a and 12 a of the fin pieces.

Even in this case, the same effects as in the above embodiment can be expected.

In the above embodiment, the tips of the fin pieces 17 are also attached to the fin root portions 12a, 12 in the same manner as the root portions 17a, 17a.
The fin pieces 17 are shaped so that the distance between a and Even if it is distorted, it has almost no effect on the effectiveness.

Further, in the above embodiment, the bending fin pieces 17 are arranged at approximately equal intervals, but it is not necessarily necessary to set them at equal intervals, and it goes without saying that they may be set at an appropriate interval.

Furthermore, it goes without saying that the same effect can be obtained whether the base portion 17H is bent before being wrapped around the heat exchanger tube 11 or after being wound around the heat exchanger tube 11.

In the above embodiment, the band-shaped fins 13 are fixed to the heat exchanger tubes 11 by soldering, but it goes without saying that they may be fixed by other means such as adhesion.

Next, the effects of the finned heat exchanger tube of the present invention will be listed below.

That is, according to the present invention, (1) A fin piece 17.17 divided into two parts is formed at the tip of each fin piece 12 of the band-shaped fin 13 wound around the outer periphery of the heat exchanger tube 11, and the fin piece 17.17 Since at least one root portion 17a of the fin piece 17 is bent in a direction substantially perpendicular to the width direction of the fin piece 12 and fixed to the heat exchanger tube 11, each fin piece 17 acts as an independent fin against the air flow. In addition, the width of the fin piece 17 serving as a substantial fin can be reduced without changing the width of the root portion 12H of the fin piece 12, and the average heat transfer coefficient on the fin surface can be reduced without reducing the strength and corrosion resistance. (2) the base 1 of at least one of the fin pieces 17j7;
By bending 7 a in a direction substantially perpendicular to the width direction of the fin pieces 12, the distance a between the fin pieces on the same plane can be increased, thereby increasing the cutting surface, narrowing the width of the fin pieces, and reducing dust. Therefore, the effect of the boundary layer of the upstream fin on the downstream fin of the airflow is reduced, and the fin surface heat transfer coefficient can be significantly improved. parallel to each other, and the distance between the fin pieces 17 and 17 is the same as that of the fin base parts 12
Since the spacing of a is made to be even, a sufficient length of each fin piece 17 can be ensured, and most of the fin pieces 12 can be made into narrow fin pieces 17. As a result, the fin surface average There are practical effects such as further improvement in heat transfer coefficient.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing a part of the inside of an outdoor unit of a general air conditioner, Fig. 2 is a partial sectional view of a conventional finned heat exchanger tube, and Fig. 3 is a sectional view taken along III-III in Fig. 2. , FIG. 4 is a graph showing the change in the fin surface heat transfer coefficient α with respect to the fin width X, FIG. 5 is a partial sectional view of the finned heat transfer tube according to the embodiment of the present invention, and FIG. -VI sectional view, FIG. 7 is a VII-VII sectional view of FIG. 6, and FIG. 8 is a partial sectional view of a finned heat exchanger tube according to another embodiment of the present invention. 10... Heat exchanger tube with fins, 11... Heat exchanger tube, 12... Fin piece, 13... Band-shaped fin, 17. ...Fin piece, 17a...
・Root part.

Claims (1)

[Scope of utility model registration request] On the outer periphery of the heat exchanger tube 11 through which the heat medium flows, a large number of fin pieces 12, 12, . Intimidate,
A band-shaped fin 13 with both ends bent into a U-shape is wound spirally and fixed, and each fin piece 12 has a fin piece formed by dividing into two in the vertical direction, leaving the vicinity of the root part 12 a. 17.17, and the base portion 17a of at least one of the fin pieces 17.17 is perpendicular to the middle direction of the fin piece 12, and both fin pieces 17.17 are parallel to each other. A finned heat exchanger tube characterized in that the fin pieces 17 and 17 are bent so that the interval between the fin pieces 17 and 17 is the same as the interval between the fin piece root parts 12 a and 12 a.