CN202853449U - Finned tube heat exchanger - Google Patents

Abstract

The utility model provides a fin tube heat exchanger. The finned tube heat exchanger (100) includes: fins (31) formed with peaks (34) and valleys (36) and having through holes (37h); heat transfer tubes (21) passing through the through holes (37h) ). The fin (31) has a peripheral inclined portion (39) protruding from the side of the through hole (37h) toward the side of the mountain portion (34) around the through hole (37h). The peripheral slope (39) has a slit (23). The slit (23) is, for example, a slit extending from the side of the through hole (37h) toward the side of the mountain portion (34).

Description

Finned tube heat exchanger

technical field

The utility model relates to a fin tube heat exchanger.

Background technique

The finned tube heat exchanger is composed of a plurality of fins arranged at predetermined intervals and a heat transfer tube passing through the plurality of fins. The air flows between the fins to exchange heat with the fluid in the heat transfer tubes.

Fig. 15 is a plan view of a fin used in a conventional fin-tube heat exchanger. The fin 1 is shaped such that peaks 4 and valleys 6 alternately appear in the airflow direction. Such fins are often referred to as "corrugated fins". According to the corrugated fins, not only the effect of increasing the heat transfer area can be obtained, but also the effect of thinning the temperature boundary layer can be obtained by making the air flow 3 meander.

As one technical problem common to finned tube heat exchangers, there is a problem related to drainage performance. When water (condensed water) adheres to the surface of the fins, effective heat exchange is hindered, so it is desirable to quickly remove the water from the surfaces of the fins. For example, Patent Document 1 describes a fin having drainage slits. The fin described in Patent Document 1 is shown in FIG. 16 . The fins 11 are provided with drain slits 8 extending obliquely downward from the drain stagnation area below the heat transfer tubes 7 .

Patent Document 1: Japanese Publication No. 64-22186

The technique described in Patent Document 1 assumes unbent fins (so-called flat fins), and its application range is not wide. Therefore, a technique applicable to corrugated fins is desired.

Utility model content

The purpose of the utility model is to improve the drainage performance of a finned tube heat exchanger using corrugated fins.

That is, the utility model provides a finned tube heat exchanger, which has:

Fins formed with hills and valleys and having through holes;

the heat transfer tube passing through the through hole,

The fin has a peripheral inclined portion raised from the side of the through hole toward the side of the mountain portion around the through hole,

The peripheral slope has a slit.

Description of drawings

Fig. 1 is a perspective view of a finned tube heat exchanger according to a first embodiment of the present invention.

FIG. 2A is a top view of a fin used in the finned tube heat exchanger of FIG. 1 .

Fig. 2B is a cross-sectional view of the fin shown in Fig. 2A along line IIB-IIB.

FIG. 2C is a cross-sectional view of the fin shown in FIG. 2A along line IIC-IIC.

Fig. 2D is a cross-sectional view of the fin shown in Fig. 2A along line IID-IID.

FIG. 3 is a plan view of a fin of Modification 1. FIG.

FIG. 4A is a plan view of a fin of Modification 2. FIG.

FIG. 4B is a cross-sectional view of the fin shown in FIG. 4A along line IVB-IVB.

FIG. 5A is a plan view showing another example of the positions of the ends of the slits.

FIG. 5B is a plan view showing still another example of the positions of the ends of the slits.

FIG. 5C is a plan view showing still another example of the position of the end portion of the slit.

FIG. 5D is a plan view showing yet another example of the position of the end portion of the slit.

Fig. 6A is an enlarged cross-sectional view of a slit.

Fig. 6B is an enlarged cross-sectional view of another slit.

Fig. 7A is an explanatory diagram of the function of a conventional fin.

Fig. 7B is an explanatory diagram of the operation of the fins of the first embodiment.

FIG. 8A is a plan view of a fin according to Modification 3. FIG.

FIG. 8B is a cross-sectional view of the fin shown in FIG. 8A along line VIIIB-VIIIB.

FIG. 8C is a plan view of a fin according to Modification 3 from which some slits are omitted.

FIG. 9A is an action explanatory view of a fin in Modification 3 without slits.

FIG. 9B is an explanatory diagram of the operation of the fins of Modification 3. FIG.

Fig. 10A is a plan view of a fin of a second embodiment.

Fig. 10B is a cross-sectional view of the fin shown in Fig. 10A along line XB-XB.

FIG. 10C is a cross-sectional view of the fin shown in FIG. 10A along line XC-XC.

FIG. 10D is a cross-sectional view of the fin shown in FIG. 10A along line XD-XD.

FIG. 11 is a plan view of a fin of Modification 4. FIG.

FIG. 12 is a partial plan view of a fin according to Modification 5. FIG.

FIG. 13A is a plan view of a fin according to Modification 6. FIG.

Fig. 13B is a cross-sectional view of the fin shown in Fig. 13A along line XIIIB-XIIIB.

Fig. 13C is a cross-sectional view of the fin shown in Fig. 13A along line XIIIC-XIIIC.

Fig. 13D is a cross-sectional view of the fin shown in Fig. 13A along line XIIID-XIIID.

FIG. 14A is a plan view of a fin according to Modification 7. FIG.

Fig. 14B is a cross-sectional view of the fin shown in Fig. 14A along line XIVB-XIVB.

Fig. 14C is a cross-sectional view of the fin shown in Fig. 14A along line XIVC-XIVC.

Fig. 14D is a cross-sectional view of the fin shown in Fig. 14A along line XIVD-XIVD.

Fig. 15 is a plan view of a conventional corrugated fin.

FIG. 16 is a plan view of a fin described in Patent Document 1. FIG.

Detailed ways

The first form of the utility model provides a finned tube heat exchanger, which has:

Fins formed with hills and valleys and having through holes;

the heat transfer tube passing through the through hole,

The fin has a peripheral inclined portion raised from the side of the through hole toward the side of the mountain portion around the through hole,

The peripheral slope has a slit.

Water adhering to the surface of the fins around the heat transfer tube usually flows downward due to its own weight. However, some of the adhered water may stagnate on the surface of the fin. Water stagnation easily occurs in corrugated fins. In the corrugated fin, as a portion where water tends to stagnate, a peripheral inclined portion is cited. The water that cannot go over the mountain stays on the surrounding slopes in a shape that minimizes the surface area and becomes stable.

On the other hand, according to this aspect, the slit is formed in the peripheral slope part. The slits guide water from the surrounding slopes towards the hills. At the same time, water is guided from the surface side of the fins to the back side of the fins through the slits. That is, water concentrates on the valley part on the back side of the fin. The water concentrated in the valley flows downward along the valley. As a result, water is effectively removed from the surface of the fins.

The second aspect of the present invention provides a finned tube heat exchanger based on the first aspect. For example, the slit may be a slit extending from the side of the through hole toward the side of the mountain portion. , the end of the ridge line of the mountain portion is located on the extension line of the slit. According to this aspect, the water permeated to the back side of the peripheral slope part through the slit can be directly collected in the valley part on the back side. Thereby, the water adhered to the surface of the fin can be efficiently removed from the surface of the fin.

The third aspect of the present invention provides a finned tube heat exchanger based on the first aspect. For example, the slit may be a slit extending from the side of the through hole toward the side of the mountain portion. , the end of the ridgeline of the mountain portion is located at a position different from the extension of the slit. According to this aspect, the water permeating to the back side of the surrounding inclined portion through the slit can be collected in the valley portion on the back side and drained from the surface of the fin.

The fourth aspect of the present invention provides a finned tube heat exchanger based on the first aspect. For example, the slit may be formed in a hole extending from the center of the through hole toward the side of the mountain portion. imaginary online. According to this aspect, the slit can efficiently guide the water collected around the heat transfer tube to the mountain portion.

The fifth form of the present invention provides a finned tube heat exchanger based on the first form. For example, the slit may be formed on the ridge line from the center of the through hole toward the mountain. An imaginary line extending from the end of . According to this aspect, the slit can more effectively guide the water collected around the heat transfer tube to the mountain portion.

A sixth aspect of the present invention provides a finned tube heat exchanger based on the first aspect. For example, the slit may be formed on an extension line of a ridge line of the mountain portion. According to this aspect, the falling speed of water from the slit to the back side of the fin can be increased. Thereby, water can be efficiently removed from the surface of the fin.

A seventh aspect of the present invention provides a finned tube heat exchanger based on the first aspect, for example, the fin may be an M-shaped fin having the two peaks.

The eighth aspect of the present invention provides a finned tube heat exchanger based on the seventh aspect. For example, the slit may be a slit extending from the side of the through hole toward the side of the mountain portion. , two slits are provided on the surrounding inclined portion.

The ninth aspect of the present invention provides a finned tube heat exchanger based on the seventh aspect. For example, the slit may be a slit extending from the side of the through hole toward the side of the mountain portion. , four slits are provided on the surrounding inclined portion.

The tenth aspect of the present invention provides a finned tube heat exchanger based on the seventh aspect. For example, the slit may be a slit extending from the side of the through hole toward the side of the valley portion. , one of the slits is provided on the surrounding inclined portion.

The eleventh aspect of the present invention provides a finned tube heat exchanger based on the seventh aspect. For example, the slit may be a slit extending from the side of the through hole toward the side of the valley portion. There are two slits provided on the surrounding inclined part.

A twelfth aspect of the present invention provides a finned tube heat exchanger based on the first aspect, for example, the fin may be a V-shaped fin having one of the peaks.

The thirteenth aspect of the present invention provides a finned tube heat exchanger based on the twelfth aspect. For example, the slit may extend from the side of the through hole toward the side of the mountain portion. Two slits are provided on the surrounding inclined portion.

A fourteenth aspect of the present invention provides a finned tube heat exchanger based on the thirteenth aspect. For example, the two slits may extend toward one of the mountain portions. According to this aspect, the water adhering to the periphery of the heat transfer tube can be concentrated more using the two slits and guided to the mountain portion, and the water can be effectively dropped to the valley on the back side.

The fifteenth aspect of the present utility model provides a finned tube heat exchanger based on any one of the first to fourteenth aspects. For example, the circumference of the through hole may be inclined to the circumference An annular flat portion is formed between the portions. According to this aspect, the water adhering to the surface of the fin around the heat transfer tube can be temporarily stagnated in the flat portion, and can flow downward along the surrounding inclined portion. Thus, more water can be effectively directed towards the back side of the fins via the slits.

A sixteenth aspect of the present invention provides a finned tube heat exchanger based on any one of the first to fourteenth aspects. For example, the width of the slit may be 0.01 mm to 1 mm.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the present invention is not limited by the following embodiments.

(first embodiment)

As shown in FIG. 1 , the finned tube heat exchanger 100 of this embodiment includes: a plurality of fins 31 arranged in parallel to form a flow path of air A (gas); twenty one. The finned tube heat exchanger 100 exchanges heat between the medium B flowing inside the heat transfer tubes 21 and the air A flowing along the surfaces of the fins 31 . The medium B is, for example, a refrigerant such as carbon dioxide or hydrofluorocarbon. The heat transfer tube 21 may be connected to one or divided into a plurality.

The fin 31 has a leading edge 30a and a trailing edge 30b. The front edge 30a and the rear edge 30b are each linear. In this embodiment, the fins 31 have a bilaterally symmetrical structure with respect to the center of the heat transfer tube 21 . Therefore, when assembling the heat exchanger 100, there is no need to consider the direction of the fins 31.

In this specification, the direction in which the fins 31 are arranged is defined as the height direction, the direction parallel to the leading edge 30a is defined as the step direction, and the direction perpendicular to the height direction and the step direction is defined as the airflow direction (the flow direction of the air A). ). In other words, the step direction is a direction perpendicular to both the height direction and the airflow direction. The airflow direction is perpendicular to the longitudinal direction of the fins 31 and parallel to the horizontal direction in the actual use state of the fin-tube heat exchanger 100 . The airflow direction, the height direction and the step direction correspond to the X direction, the Y direction and the Z direction respectively.

As shown in FIGS. 2A to 2D , the fin 31 typically has a rectangular flat plate shape. The length direction of the fins 31 coincides with the step direction. In the present embodiment, the fins 31 are arranged at constant intervals (fin pitch FP). However, the distance between two fins 31 adjacent to each other in the height direction does not have to be constant, and may be different. The fin pitch FP is adjusted to, for example, a range of 1.0 to 1.5 mm. As shown in FIG. 2B , the fin pitch FP is represented by the distance between two adjacent fins 31 .

The portion of constant width comprising the leading edge 30a and the portion of constant width comprising the trailing edge 30b are parallel to the direction of air flow. However, these parts are used for fixing the fin 31 to the die during molding, and do not greatly affect the performance of the fin 31 .

As the material of the fins 31 , a punched aluminum flat plate having a thickness of 0.05 to 0.8 mm can be preferably used. Hydrophilic treatment such as boehmite treatment and application of a hydrophilic paint may be performed on the surface of the fins 31 . Hydrophobic treatment may be performed instead of hydrophilic treatment.

A plurality of through-holes 37h are formed in a row in the fin 31 along the step direction at equal intervals. A straight line passing through each center of the plurality of through-holes 37h is parallel to the step direction. The heat transfer tubes 21 are respectively fitted in the plurality of through-holes 37h. Around the through hole 37h, a fin ring 37 is formed through a part of the fin 31, and the fin ring 37 is in close contact with the heat transfer tube 21. As shown in FIG. The diameter of the through hole 37h is, for example, 1 to 20 mm, and may be 4 mm or less. The diameter of the through hole 37h matches the outer diameter of the heat transfer tube 21 . The center-to-center distance (pipe pitch) of two through-holes 37h adjacent to each other in the step direction is, for example, 2 to 3 times the diameter of the through-hole 37h. Moreover, the length of the fin 31 in the airflow direction is, for example, 15 to 25 mm.

As shown in FIGS. 2A to 2D , the fins 31 are formed such that peaks 34 and valleys 36 alternately appear in the airflow direction. The mountain portion 34 and the valley portion 36 are located between adjacent heat transfer tubes 21 . The ridgelines of the mountain portion 34 and the valley lines of the valley portion 36 are respectively parallel to the step direction. That is, the fin 31 is what is called a corrugated fin. When the portion of the fin ring 37 protruding in the same direction as the protruding direction is defined as the "mountain 34", in the present embodiment, the fin 31 has two mountain portions 34 and one valley portion in the airflow direction. 36. The position of the valley portion 36 coincides with the position of the center of the heat transfer tube 21 in the airflow direction. However, the positional relationship between the valley portion 36 and the heat transfer tube 21 and the positional relationship between the mountain portion 34 and the heat transfer tube 21 are not particularly limited. The number of peaks 34 and the number of valleys 36 are not particularly limited, either.

The fin 31 also has a flat portion 35 , a first inclined portion 38 , and a second inclined portion 39 (surrounding inclined portion). The flat portion 35 is a portion adjacent to the fin ring 37 and is a tube peripheral portion formed around the through hole 37h. The flat part 35 is formed between the through hole 37h and the second inclined part 39, and has a ring shape in plan view. The surface of the flat portion 35 is parallel to the airflow direction and perpendicular to the height direction. However, the flat portion 35 may also be slightly inclined with respect to the airflow direction. The first inclined portion 38 is a portion inclined with respect to the airflow direction so as to form the mountain portion 34 and the valley portion 36 . The first inclined portion 38 occupies the largest area among the fins 31 . The surface of the first inclined portion 38 is flat. The second inclined portion 39 is a portion that smoothly connects the flat portion 35 and the first inclined portion 38 to eliminate the difference in height between the flat portion 35 and the first inclined portion 38 . The surface of the second inclined portion 39 is composed of a gentle curved surface. That is, the second inclined portion 39 is an inclined portion that protrudes from the through hole 37h toward the side of the mountain portion 34 . The flat portion 35 and the second inclined portion 39 form a concave portion around the fin ring 37 and the through hole 37h. It should be noted that, in this embodiment, the second inclined portion 39 is divided into two according to the position of the valley portion 36 , but it can also be regarded as a ring-shaped second inclined portion 39 formed around one flat portion 35 . Inclined portion 39 .

An appropriate rounding (for example, R0.5 mm to R2.0 mm) may be given to the boundary portion between the first inclined portion 38 and the second inclined portion 39 . Similarly, an appropriate rounding (for example, R0.5 mm to R2.0 mm) may be given to the boundary portion between the mountain portion 34 and the second slope portion 39 .

As shown in FIGS. 2A and 2D , the fin 31 also has a slit 23 formed in the second inclined portion 39 . The slit 23 penetrates the fin 31 and extends from the side of the through hole 37h toward the side of the mountain portion 34 . Specifically, the slit 23 extends from the flat portion 35 side toward the mountain portion 34 side. The slit 23 has a length direction inclined or perpendicular to the air flow direction. In this embodiment, the end 45 of the ridge line of the mountain portion 34 is located on the extension line of the slit 23 . From another point of view, the slit 23 is formed on an imaginary line extending from the center of the through hole 37 h (the center 25 of the heat transfer tube 21 ) toward the end 45 of the ridge line of the mountain portion 34 . According to such slits 23 , water can be guided from the flat portion 35 and the second inclined portion 39 to the mountain portion 34 . At the same time, water is guided from the front side of the fin 31 to the back side of the fin 31 through the slit 23 . That is, water concentrates on the valley portion on the back side of the fin 31 . The water concentrated in the valley flows downward along the valley. As a result, water is effectively removed from the surface of the fin 31 .

In the actual use state ( FIG. 1 ) of the finned tube heat exchanger 100 , the slit 23 is formed so as to be located in at least the lower half region of the second inclined portion 39 . Specifically, the second inclined portion 39 is bounded by a plane H perpendicular to the step direction and passing through the center 25 of the heat transfer tube 21 , and includes an upper region 39 a and a lower region 39 b. In this embodiment, the slits 23 are formed in the upper region 39a and the lower region 39b, respectively. Thereby, the drainage effect by the slit 23 can fully be acquired. Since the fins 31 have a vertically symmetrical structure, the assembly of the finned tube heat exchanger 100 becomes easy.

However, the slit 23 may be formed in at least one selected from the upper region 39 a and the lower region 39 b. As shown in FIG. 3 , in the fin 31B of Modification 1, the slit 23 is formed in the lower region 39 b. Specifically, the slit 23 is formed only in the lower region 39b. Also in this configuration, the drainage effect by the slit 23 can be sufficiently obtained.

In addition, "the actual use state of the fin-tube heat exchanger 100" means the state which installed the fin-tube heat exchanger 100 so that the longitudinal direction of the fin 31 may become substantially parallel to a vertical direction. When the finned tube heat exchanger 100 is used in such an installed state, water is less likely to accumulate on the surface of the fins 31 .

In this embodiment, the fin 31 is an M-shaped corrugated fin in which mountain portions 34 are formed at a plurality of positions in the airflow direction. The plurality of slits 23 are formed in the second inclined portion 39 in shapes corresponding to the peak portions 34 , respectively. In the present embodiment, since two mountain portions 34 exist along the airflow direction, a plurality of slits 23 are formed in the second slope portion 39 in order to guide water to the two mountain portions 34 . Specifically, four slits 23 are formed around one flat portion 35 . That is, four slits 23 are formed in the second inclined portion 39 . According to this structure, an excellent drainage effect can be obtained. Of course, two slits 23 may be formed in the second inclined portion 39 like the fin 31B shown in FIG. 3 . Also according to this structure, sufficient drainage effect can be obtained.

In the present embodiment, at least one slit 23 is formed around all the flat portions 35 . Accordingly, the drainage effect by the slit 23 can be obtained around all the flat portions 35 . However, this need not be the case. For example, the slit 23 may be formed only around one of the two adjacent flat portions 35 . In this case, a certain drainage effect can also be obtained.

The longitudinal direction of the slit 23 is preferably substantially along the direction of gravity. Thereby, not only the water on the flat portion 35 and the second inclined portion 39 can be quickly guided to the mountain portion 34, but also the water on the flat portion 35 and the second inclined portion 39 can be quickly guided from the front side of the fin 31. dorsal side. For example, the longitudinal direction of the slit 23 can be determined such that the angle formed by a straight line parallel to the longitudinal direction of the slit 23 and a straight line parallel to the longitudinal direction of the fin 31 is 45 degrees or less. In the present embodiment, the slit 23 has a center line CL parallel to the longitudinal direction. The center 25 (the center of the through-hole 37h) of the heat transfer tube 21 is located on the extension line of the center line CL. When the slit 23 extends in such a direction, the slit 23 is less likely to hinder the heat conduction of the fin 31 . The reason for this is as follows.

The temperature distribution of the fins 31 in the vicinity of the heat transfer tube 21 generally spreads substantially concentrically around the heat transfer tube 21 . When the center 25 of the heat transfer tube 21 is located on the extension line of the centerline CL of the slit 23, the temperature of the fins 31 on the left side of the centerline CL is substantially the same as the temperature of the fins 31 on the right side of the centerline CL. Even assuming that no slit 23 is provided, heat hardly moves in a direction crossing the slit 23 . Therefore, according to the present embodiment, the heat transfer performance of the fins 31 can be maintained.

However, the longitudinal direction of the slit 23 is not particularly limited as long as the drainage performance can be improved. As shown in FIGS. 4A and 4B , in the fin 31C of Modification 2, the longitudinal direction of the slit 23 is parallel to the vertical direction (the longitudinal direction of the fin 31C). In other words, the length direction of the slit 23 is perpendicular to the airflow direction. The slit 23 is formed on the extension line EL of the ridge line of the mountain portion 34 .

As shown in FIG. 2A , in the present embodiment, both end portions of the slit 23 are in contact with the flat portion 35 and the mountain portion 34 , respectively. According to such a configuration, water is efficiently collected from the flat portion 35 and the second inclined portion 39 to the mountain portion 34 . However, the position of the end of the slit 23 is not particularly limited as long as a certain water collecting effect can be exhibited.

For example, as shown in FIG. 5A , both end portions of the slit 23 may be separated from the flat portion 35 and the mountain portion 34 . As shown in FIG. 5B , the slit 23 may have one end in contact with the flat portion 35 and the other end separated from the mountain portion 34 . As shown in FIG. 5C , the slit 23 may have one end separated from the flat portion 35 and the other end in contact with the mountain portion 34 (specifically, the edge 45 of the mountain portion 34 ). As shown in FIG. 5D , the other end of the slit 23 may also be located on the ridge line between the first inclined portion 38 and the second inclined portion 39 . In other words, the end 45 of the ridgeline of the mountain portion 34 may be located at a position different from the extension of the slit 23 . Furthermore, the ridgeline of the mountain portion 34 may be separated from the extension line of the slit 23 . Even in this case, the slit 23 extends from the flat portion 35 side to the mountain portion 34 side. In other words, in FIGS. 5A to 5D , the slit 23 is formed on an imaginary line extending from the center of the through hole 37 h (the center 25 of the heat transfer tube 21 ) toward the mountain portion 34 side. Therefore, the function of guiding water to the mountain portion 34 can be exhibited. However, when the end of the slit 23 is in contact with the flat portion 35 or the mountain portion 34, it is preferable because an excellent water collecting function can be exhibited.

It should be noted that it is not essential that the slit 23 is formed on an imaginary line extending from the center of the through hole 37h toward the end 45 of the ridge line of the mountain portion 34 . For example, the slit 23 may be formed on an imaginary line extending from a position deviated from the center of the through hole 37h toward the mountain portion 34 side. Furthermore, the slit 23 may be formed on an imaginary line extending from a position deviated from the center of the through hole 37h toward the end 45 of the ridge line of the mountain portion 34 . The slit 23 is preferably formed in the second inclined portion 39 so as to extend toward the end portion 45 of the ridge line of the mountain portion 34 .

The width of the slit 23 is not particularly limited. However, the slit 23 preferably has a width G capable of guiding water from the front side of the fin 31 to the back side of the fin 31 by capillary action. According to this structure, water can be efficiently removed from the surface of the fin 31 .

The width G of the slit 23 can be adjusted within the range of, for example, 0.01 to 1 mm (preferably 0.05 to 0.3 mm). When the fin pitch FP is used as a reference, the width G of the slit can be adjusted so as to satisfy the relationship of 0.005FP<G<FP (preferably 0.025FP<G<0.3FP). When the width G is adjusted within such a range, water is smoothly guided from the front side of the fin 31 to the back side of the fin 31 . The "fin pitch FP" represents the interval between fins adjacent to each other.

The cross-sectional shape of the slit 23 is not particularly limited. A specific example of the cross-sectional shape of the slit 23 is shown in FIGS. 6A and 6B . The example shown in FIG. 6A is formed by applying a shear load to the fin 31 in the thickness direction. That is, when observing the cross section perpendicular to the longitudinal direction of the slit 23, the second inclined portion 39 on one side (left side) of the slit 23 and the second inclined portion 39 on the other side (right side) of the slit 23 The slit 23 is formed by providing a step difference between the portions 39 . The slit 23 shown in FIG. 6B is formed by piercing the fin 31 from one side of the fin 31 with a sharp knife (for example, a part fitted into a mold). That is, when viewing a cross section perpendicular to the longitudinal direction of the slit 23, one side (left side) and the other side (right side) of the slit 23 may be deformed by arcuately deforming the second inclined portion 39, respectively. Slits 23 are formed. Regardless of the shape of the slit 23, the effect of improving the drainage performance of the fin 31 can be obtained. It should be noted that the direction of processing when forming the slit 23 is not particularly limited.

Next, the function of the slit 23 will be described in detail with reference to FIGS. 7A and 7B . 7A and 7B show the surface state of the fins in time series.

As shown in FIG. 7A , in the conventional fin 1 , water W adheres to the surface of the fin 1 around the heat transfer tube 2 (left figure). The water W flows downward (in the direction of gravity) along the folds of the fin 1 and starts to stagnate in the flat portion 5 and the inclined portion 9 . A part of the water W overflows along the valley 6 and then flows downward (center figure). However, the rest of the water W remains on the flat portion 5 and the inclined portion 9 due to surface tension, and does not flow downward, but stays around the heat transfer tube 2 (right figure). In the subsequent operation, the performance of the heat exchanger is greatly reduced because the water W hinders the flow of air and acts as a large thermal resistance.

On the other hand, the fin 31 of this embodiment has the following operation and effect. As shown in FIG. 7B , water W adheres to the surface of the fin 31 around the heat transfer tube 21 (left figure). The water W flows downward along the creases of the fins 31 and starts to stagnate in the flat portion 35 and the second inclined portion 39 . A part of the water W overflows along the valley portion 36 and then flows downward. The rest of the water W passes through the slit 23 due to the influence of surface tension (capillarity) and gravity, and permeates from the front side of the fin 31 to the back side of the fin 31 . On the back side of the fin 31 , the mountain portion 34 constitutes a valley portion, and the valley portion 36 constitutes a mountain portion. Therefore, the destination where the water W reaches through the slit 23 is the valley. The water W permeated to the back side of the fin 31 through the slit 23 flows downward along the valley (dotted line in the central figure). In this way, the water W is sufficiently removed from the surface of the fin 31 (right figure). As a result, the original performance of the finned tube heat exchanger 100 can be continuously exhibited.

When the finned tube heat exchanger 100 of this embodiment is used in the outdoor unit of the heat pump system, the benefit obtained by the improvement of drainage performance increases dramatically.

Generally, when the outside air temperature approaches 0° C., frost starts to accumulate on the surface of the fins of the finned tube heat exchanger incorporated in the outdoor unit. Frost greatly impairs the performance of the finned tube heat exchanger, so it is necessary to periodically perform an operation for melting and removing the frost, that is, a so-called defrosting operation. However, according to the conventional fin 1 , water generated by melting frost cannot be sufficiently removed from the surface of the fin 1 . Therefore, part of the water generated by the melting of frost remains on the surface of the fin 1 as it is, and refreezing occurs after the defrosting operation is completed. That is, melting of frost and freezing of remaining water consume energy unnecessarily. When frost (or ice) accumulates on the surface of the fin 1 due to refreezing, it is urgently necessary to shorten the interval between defrosting operations.

On the other hand, as described with reference to FIG. 7B , since the finned tube heat exchanger 100 of this embodiment has excellent drainage performance, the water generated during the defrosting operation is quickly drained from the surface of the fins 31 . Thereby, disadvantages such as excessive energy consumption and shortened intervals between defrosting operations can be avoided. After the defrosting operation, water is sufficiently removed from the surface of the fins 31, so that the original performance of the fin-tube heat exchanger 100 can be reliably exhibited.

According to the fin 31 described with reference to FIGS. 2A to 2D , the position of the flat portion 35 coincides with the position of the valley portion 36 in the height direction (Y direction). According to such a structure, even if the slit 23 does not exist, as demonstrated with reference to FIG. However, this structure is not necessary.

As shown in FIGS. 8A and 8B , according to the fin 31D according to Modification 3, the positions of the flat portion 35 and the position of the valley portion 36 are different in the height direction, and coincide with the positions of the leading edge 30 a and the trailing edge 30 b. In the height direction, the valley portion 36 is located between the flat portion 35 and the mountain portion 34 , and a height difference is generated between the valley portion 36 and the flat portion 35 . The height difference between the valley portion 36 and the flat portion 35 is eliminated by the annular second inclined portion 39 formed around the flat portion 35 .

In the fin 31D, the slit 23 is formed at the following positions. That is, a plane passing through the center 25 of the heat transfer tube 21 (the center of the through-hole 37h) and perpendicular to the airflow direction is defined as the first central plane P1. The slit 23 is formed in the second inclined portion 39 so as to overlap the first central plane P1. In detail, the slit 23 overlaps with the first central plane P1 and extends along the step direction. That is, the longitudinal direction of the slit 23 is parallel to the valley line of the valley portion 36 . Furthermore, the slit 23 extends from the side of the through hole 37h toward the side of the valley portion 36 . Specifically, the slit 23 extends from the flat portion 35 side toward the valley portion 34 side. Furthermore, in this modified example, the slit 23 may be formed in both the upper region 39a and the lower region 39b, or may be formed in only one selected from the upper region 39a and the lower region 39b. Seam 23. That is, two slits 23 may be formed in the second inclined portion 39 as shown in FIG. 8A , or one slit 23 may be formed in the second inclined portion 39 as shown in FIG. 8C . In the latter case, typically, the slit 23 is formed only in the lower region 39b.

As shown in FIG. 9A , when the slit 23 is not formed, part of the water W overflows along the valley portion 6 and flows downward (left and center diagrams). However, the rest of the water W remains on the flat portion 5 and the inclined portion 9 due to surface tension, and does not flow downward, but stays around the heat transfer tube 2 (right figure). Since there is a difference in height between the flat portion 5 and the valley portion 6, the amount of the stagnant water W tends to increase.

As shown in FIG. 9B, according to the fin 31D of this modified example, the water W permeates from the front side to the back side of the fin 31D through the slit 23, spreads from the mountain to the valley, and then flows downward along the valley (left). figure and central figure). Therefore, water W is sufficiently excluded from the surface of the fin 31D (right figure). The fin 31D exerts the same function as that of the fin 31 described with reference to FIG. 7B .

(second embodiment)

As shown in FIGS. 10A to 10D , the fin 31F of the second embodiment is a V-shaped corrugated fin formed so that the mountain portion 34 appears only at one position in the airflow direction. The fin 31F of this embodiment has the flat part 35, the 1st inclination part 38, the 2nd inclination part 39, and the slit 23 similarly to the fin 31 of 1st embodiment. The slit 23 is formed in the second inclined portion 39 and extends from the side of the through hole 37h toward the side of the mountain portion 34 . Specifically, the slit 23 extends from the flat portion 35 side toward the mountain portion 34 side. That is, the constituent elements of the fin 31F of the present embodiment are identical to those of the fin 31 of the first embodiment, as denoted by the same reference numerals, except for the point where the mountain portion 34 is formed at only one position in the airflow direction. The structural elements are the same. Therefore, as long as there is no technical contradiction, all the descriptions related to the first embodiment and its modifications can be referred to the fin 31F of this embodiment and its modifications.

In the fin 31F of this embodiment, like the fin 31 of the first embodiment, the drainage performance is improved by the slit 23 .

As shown in FIG. 10A, the longitudinal direction of the slit 23 is perpendicular to the airflow direction. Specifically, the slit 23 has a center line CL parallel to the longitudinal direction of the slit 23 . Since the longitudinal direction of the slit 23 is parallel to the gravity direction and the step direction, the center line CL is also parallel to the gravity direction and the step direction. When the fin 31F is viewed from above, the ridge line of the mountain portion 34, the center 25 of the heat transfer tube 21, and the center line CL of the slit 23 exist on the same straight line perpendicular to the airflow direction. One end (upper end) of the slit 23 is located at or near the lower end of the annular flat portion 35 . According to such a positional relationship, since almost no water remains in the flat portion 35 and the second inclined portion 39, a drastic improvement in drainage performance can be expected.

Like the first embodiment, in this embodiment, the slit 23 is formed on an imaginary line extending from the center of the through hole 37h (the center 25 of the heat transfer tube 21 ) toward the mountain portion 34 side. Furthermore, the end portion 45 of the ridge line of the mountain portion 34 is located on the extension line of the slit 23 . Therefore, also in this embodiment, the same effects as those described in the first embodiment can be obtained.

The fin 31F in this embodiment is a V-shaped corrugated fin. Therefore, all the water guided from the front side of the fin 31F to the back side through the slit 23 gathers in one valley. That is, since more water is concentrated in one valley than in the M-shaped corrugated fin (first embodiment), the concentrated water easily flows downward. Thus, the drainage performance of the fin 31F of this embodiment is equal to or exceeds the drainage performance of the fin 31 (M-shaped corrugated fin) of 1st Embodiment. If the length in the airflow direction is constant, the surface area of the V-shaped corrugated fin exceeds the surface area of the M-shaped corrugated fin. Therefore, the heat exchange performance of the V-shaped corrugated fins is equal to or exceeds that of the M-shaped corrugated fins.

In the fin 31F of the present embodiment, the slits 23 are respectively formed in the upper region 39 a of the second inclined portion 39 and the lower region 39 b of the second inclined portion 39 . That is, two slits 23 are formed in the second inclined portion 39 . However, as described in the first embodiment, the slit 23 may be formed in at least one selected from the upper region 39 a and the lower region 39 b. As shown in FIG. 11 , in the fin 31G of Modification 4, the slit 23 is formed in the lower region 39 b. Specifically, the slit 23 is formed only in the lower region 39b.

In the present embodiment, the structure of the slit 23 is not particularly limited as long as the drainage effect can be exerted. For example, like the fin 31 of the first embodiment, the slit 23 may be inclined with respect to both the air flow direction and the step direction. As described with reference to FIGS. 5A to 5D , the positions of both ends of the slit 23 are not particularly limited. Furthermore, as shown in FIG. 12 , a plurality of slits 23 (for example, two slits 23 ) are formed in the fin 31H of Modification 5 so as to extend toward one mountain portion 34 .

(other modifications)

As shown in FIGS. 13A to 13D , the fin 31I of Modification 6 does not have the flat portion 35 . The second inclined portion 39 (peripheral inclined portion) is adjacent to the fin ring 37 and gently rises from the side of the through hole 37h toward the mountain portion 34 . The structure of the fin 31I is the same as that of the fin 31 of the first embodiment except for the point that it does not have the flat portion 35 . Furthermore, as shown in FIGS. 14A to 14D , the fin 31J of Modification 7 does not have the flat portion 35 either. The structure of the fin 31J is the same as that of the fin 31F of the second embodiment except for the point that it does not have the flat portion 35 . In this way, the flat portion 35 is not essential and may be omitted.

In the fin shown in FIG. 4A , FIGS. 5A to 5D and FIG. 12 , the slit 23 is formed only in the lower region 39 b of the second inclined portion 39 . However, one or more slits 23 may be formed in the region 39a on the upper side of the second inclined portion 39 so that the fins shown in FIGS. Slit23.

【Industrial availability】

The finned tube heat exchanger disclosed in this specification is useful for heat pumps used in air conditioners, water heaters, heating devices, and the like. Especially useful in evaporators for evaporating refrigerants.

Claims (16)

1. A finned tube heat exchanger, characterized in that it possesses: Fins formed with hills and valleys and having through holes; the heat transfer tube passing through the through hole, The fin has a peripheral inclined portion raised from the side of the through hole toward the side of the mountain portion around the through hole, The peripheral slope has a slit. 2. The finned tube heat exchanger according to claim 1, characterized in that, The slit is a slit extending from the side of the through hole toward the side of the mountain portion, and the end of the ridgeline of the mountain portion is located on an extension line of the slit. 3. The finned tube heat exchanger according to claim 1, characterized in that, The slit is a slit extending from the side of the through hole toward the side of the mountain portion, and the end of the ridgeline of the mountain portion is located at a position different from the extension of the slit. 4. The finned tube heat exchanger according to claim 1, characterized in that, The slit is formed on an imaginary line extending from the center of the through hole toward the mountain portion side. 5. The finned tube heat exchanger according to claim 1, characterized in that, The slit is formed on an imaginary line extending from the center of the through hole toward the end of the ridge line of the mountain portion. 6. The finned tube heat exchanger according to claim 1, characterized in that, The slit is formed on an extension line of a ridge line of the mountain portion. 7. The finned tube heat exchanger according to claim 1, characterized in that, The fin is an M-shaped fin having two of the peaks. 8. The finned tube heat exchanger according to claim 7, characterized in that, The slit is a slit extending from the side of the through hole toward the side of the mountain portion, Two slits are provided on the peripheral slope. 9. The finned tube heat exchanger according to claim 7, characterized in that, The slit is a slit extending from the side of the through hole toward the side of the mountain portion, Four slits are provided on the peripheral slope. 10. The finned tube heat exchanger according to claim 7, characterized in that, The slit is a slit extending from the side of the through hole toward the side of the valley portion, One of the slits is provided in the peripheral inclined portion. 11. The finned tube heat exchanger according to claim 7, characterized in that, The slit is a slit extending from the side of the through hole toward the side of the valley portion, Two slits are provided on the peripheral slope. 12. The finned tube heat exchanger according to claim 1, characterized in that, The fin is a V-shaped fin having one of the peaks. 13. The finned tube heat exchanger according to claim 12, characterized in that, The slit is a slit extending from the side of the through hole toward the side of the mountain portion, Two slits are provided on the peripheral slope. 14. The finned tube heat exchanger according to claim 13, characterized in that, Two of the slits extend toward one of the mountain portions. 15. The finned tube heat exchanger according to any one of claims 1 to 14, characterized in that, An annular flat portion is formed between the periphery of the through hole and the surrounding inclined portion. 16. The finned tube heat exchanger according to any one of claims 1 to 14, characterized in that, The width of the slit is 0.01 mm to 1 mm.

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