JP2006112731A - Small-diameter heat transfer tube unit for small-diameter multitubular heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further improve the heat exchanging performance of a small-diameter multitubular heat exchanger by using a heat transfer accelerating member. <P>SOLUTION: Cut and raised pieces 45a, 45b and 45c such as slits and louvers formed on a heat transfer fin 42 are formed into approximate squares, and a wide and large heat transfer area for sufficiently transferring heat to a central portion of the fin is secured, thus effective heat transfer acceleration is enabled without unreasonably impairing the efficiency of the fin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a structure of a small-diameter heat transfer tube unit of a small-diameter multi-tube heat exchanger.

  Recently, for example, a plurality of tubes having an annular cross section with a small diameter of about 0.2 mm to 0.8 mm are provided between an inlet tank and an outlet tank that are arranged to face each other at a predetermined interval. A core portion through which an external fluid flows is formed by arranging the pitch L between the tubes to be about 1d to 2d of the tube diameter d of the tube, and further, the flow of the external fluid through the plurality of tubes of the core portion. There has been proposed a heat exchanger that employs a small-diameter multi-tube heat transfer tube structure that is arranged in a square grid pattern in the direction and has improved contact efficiency with an external fluid (see, for example, Patent Document 1).

  Compared to fin-and-tube heat exchangers that are generally used as heat exchangers such as air conditioners, such small-diameter multi-tube heat exchangers have higher performance, Since the ventilation resistance is smaller, it is possible to function as a highly efficient heat exchanger.

  However, in the case of the configuration of such a small-diameter multi-tube heat exchanger, since the core portion is composed of an assembly of small-diameter heat transfer tubes, the heat transfer coefficient itself as a heat transfer tube heat exchanger is high, but each other Since the heat transfer area of each heat transfer tube is small, a larger number of small-diameter heat transfer tubes are required to achieve higher performance than a certain level. As a result, the structure is complicated and the assembly is complicated.

  In addition, the heat transfer tube group of the same small diameter is provided with a large number of flow paths in a grid pattern in the flow direction of the external fluid (air) to flow the internal fluid (water). Since the amount of heat exchange for each flow path varies depending on the position, drift tends to occur, and this tendency is particularly noticeable when a gas-liquid two-phase refrigerant is flowed as in an air conditioner.

  Therefore, it is good when the cooling water that does not change the phase state, such as an automobile radiator, is used as the internal fluid, but it is used when the refrigerant that changes the phase state, such as the air conditioner, is used as the internal fluid. It was difficult to do.

  Therefore, based on such circumstances, by adding fins to each tube body portion of the above-mentioned small-diameter heat transfer tube, the specification conditions of each tube body portion and fin portion are formed so as not to cause drift. In addition to the heat transfer coefficient, it has been considered to provide a small-diameter multi-tube heat exchanger that can effectively increase the heat transfer area and can be effectively used in an air conditioner or the like.

  An example of the configuration of the small-diameter multi-tube heat exchanger provided with the heat transfer fins and the small-diameter heat transfer tube unit constituting the heat exchanger is shown in FIGS.

  That is, first, a small-diameter multitubular heat exchanger 1 shown in FIG. 14 includes an inlet header 2A and an outlet header 2B having a refrigerant distribution function arranged in parallel with each other at a predetermined interval, and the inlet header 2A and the outlet Each of the headers 2B is connected to each of the headers 2B and is composed of a heat exchange section 3 including a plurality of small-diameter heat transfer tube units 4, 4...

  As shown in FIGS. 15 and 16, for example, the small-diameter heat transfer tube units 4, 4,... While the portions 41c and 41d are connected to the respective openings on the bottom side of the inlet header 2A and the outlet header 2B, the two straight tube portions 41a on the left and right sides of the U-shaped heat transfer tube 41, 41b is provided with fin portions 42a, 42b, and 42c having predetermined widths respectively located on the upstream side, the middle stream side, and the downstream side of the air flow. These fin portions 42 a, 42 b, 42 c are continuous with each other to form one heat transfer fin 42 for the U-shaped heat transfer tube 41.

  And the thin-diameter heat transfer tube units 4, 4. The thin and flat heat transfer fin plates (bonding members) 4A and 4B are joined and integrated in a state of facing each other as shown in FIG. The small-diameter heat transfer tube units 4, 4... Are formed by integrally forming the fin portions 42a, 42b, 42c on the left and right sides of the straight tube portions 41a, 41b.

  The small-diameter heat transfer tube units 4, 4... Configured as described above are arranged in parallel with the flow direction of the external fluid F, for example, as shown in FIG. The inlet header 2A and the outlet header 2B are connected to the open ends 41c and 41d for connection to the upper headers 2A and 2B of the units 4, 4..., And the small diameter multitubular heat exchanger 1 as shown in FIG. Is formed.

  According to the configuration as described above, the heat transfer fins 42 (fin portions 42a, 42b, fins 42a, 42b, etc.) for further expanding the heat transfer area are provided on both sides of the tube portions 4141a, 41b of the small-diameter heat transfer tube 41, which originally has a high heat transfer rate. 42c) is added, in addition to the good heat transfer coefficient by the tube portions 41a, 41b, 41a, 41b... The exchange performance is greatly improved, and it is suitable for use conditions as a heat exchanger for a refrigerating apparatus such as an air conditioner.

Japanese Patent Laid-Open No. 2001-116481 (Specification, page 1-3, FIG. 1-4)

  By the way, when it is going to improve the heat exchange performance of such a small diameter multi-tube heat exchanger further, as shown, for example in FIGS. 18-20, fin part 42b, 42c part of the heat-transfer fin 42 It is conceivable that a large number of cut and raised pieces 45a, 45a,..., 45b, 45b.

  However, the heat transfer fins 42b sandwiched between the two front and rear tube portions 41a and 41b through which the internal fluid flows are located at both ends, so that the flow direction of the external fluid F is as shown in the figure. When a large number of cut-and-raised pieces 45a, 45a,..., 45b, 45b, etc., such as vertically extending slits (or louvers) extending vertically, heat from the tube portions 41a, 41b is transferred to the heat transfer fins. There is a problem that the fin efficiency is lowered without being transmitted to the central portion of 42b, and a sufficient promotion effect cannot be obtained.

  This problem is similar to some extent even in the fin portions 42a and 42c outside the tube portions 41a and 41b.

  The present invention was made in order to solve such problems. The slits, louvers, and other cut-and-raised pieces installed in the heat transfer fin portion are substantially square, and the fin continuous portion where heat is transferred to the fin central portion is provided. It is an object of the present invention to provide a small-diameter heat transfer tube unit of a small-diameter multitubular heat exchanger that can promote heat transfer without unduly reducing fin efficiency by ensuring a large amount.

  In order to achieve the object, the present invention includes the following problem solving means.

(1) First Problem Solving Means The first problem solving means of the present invention is a small-diameter tube body portion 41a, 41b that allows heat exchange between the internal fluid and the external fluid F, and the tube body portion 41a. , 41b, a plurality of small-diameter heat transfer tube units 4, 4... Composed of heat transfer fins 42a, 42b, 42c are arranged in parallel with a predetermined interval parallel to the direction in which the external fluid F flows. A thin heat transfer tube unit of the heat transfer tube type heat exchanger formed as described above, wherein the fin surfaces of the heat transfer fins 42a, 42b, 42c are substantially square cut and raised pieces 45a, 45a,. 45b ..., 45c, 45c ... are provided.

  Thus, when the cut-and-raised pieces 45a, 45a ..., 45b, 45b ..., 45c, 45c ... provided on the fin surfaces of the heat transfer fins 42a, 42b, 42c are substantially square, The gap area between each of the raised and raised pieces 45a, 45a ..., 45b, 45b ..., 45c, 45c ... with continuous fin surfaces increases, and depending on the fin width, the center part or the outer periphery is surely secured. In addition, it is possible to ensure a wide and uniform heat conduction region through which heat from the tube portions 41a and 41b is conducted.

  Therefore, without reducing the fin efficiency itself of the heat transfer fins 42a, 42b, 42c, it is effective due to the leading edge effect of the cut and raised pieces 45a, 45a, ..., 45b, 45b ..., 45c, 45c ... The heat transfer promoting function can be fully exhibited.

(2) Second Problem Solving Means The second problem solving means of the present invention is that, in the configuration of the first problem solving means described above, the small-diameter heat transfer tube unit 4 has a groove portion for forming the tube portions 41a and 41b. Are formed by bonding the two heat transfer fin plates 4A and 4B having the cut and raised pieces 45a, 45a, ..., 45b, 45b, ..., 45c, 45c, ... The two heat transfer fin plates 4 </ b> A and 4 </ b> B are integrally cut and raised at the same position.

  In this way, the small-diameter heat transfer tube unit 4 is formed by bonding the two heat transfer fin plates 4A and 4B having the recessed groove portions for forming the tube portions 41a and 41b. 45a, 45a ..., 45b, 45b ..., 45c, 45c ... are formed by cutting and raising both of the two heat transfer fin plates 4A, 4B to be bonded at the same position. , 45b, 45b..., 45c, 45c... Are easy to form, and the tube sections 41a, 41b have a small passage cross-sectional area. 41a, 41b... Part of the contracted flow that bends and flows laterally at the portion is formed inside the cut and raised pieces 45a, 45a..., 45b, 45b. Opposing through the formed opening Effectively becomes to flow by bypassing the next side of the passage, more flow resistance is reduced.

  Therefore, the heat exchange performance can be improved more effectively.

(3) Third Problem Solving Means The third problem solving means of the present invention is that, in the configuration of the first problem solving means described above, the small-diameter heat transfer tube unit 4 has a groove portion for forming the tube portions 41a and 41b. Are formed by bonding two heat transfer fin plates 4A and 4B each having the following, and the cut and raised pieces 45a, 45a..., 45b, 45b..., 45c, 45c. It is formed by cutting and raising only one of the two heat transfer fin plates 4A and 4B.

  In this way, the small-diameter heat transfer tube unit 4 is formed by bonding the two heat transfer fin plates 4A and 4B having the recessed groove portions for forming the tube portions 41a and 41b. 45a, 45a ..., 45b, 45b ..., 45c, 45c ... are formed by cutting and raising only one of the two heat transfer fin plates 4A, 4B to be bonded together. .., 45b, 45b..., 45c, 45c... To improve the heat transfer promotion function, the heat transfer fin 42a. , 42b, 42c need not be reduced at all.

  Moreover, not only does it reduce, but rather the heat transfer area is expanded by the amount of cut and raised pieces 45a, 45a..., 45b, 45b.

  Therefore, the heat exchange performance can be more effectively improved without causing a decrease in fin efficiency.

(4) Fourth Problem Solving Means According to a fourth problem solving means of the present invention, in the configuration of the first problem solving means, the small-diameter heat transfer tube unit 4 has a groove portion for forming the tube portions 41a and 41b. Are formed by bonding the two heat transfer fin plates 4A and 4B having the cut and raised pieces 45a, 45a, ..., 45b, 45b, ..., 45c, 45c, ... Each of the two heat transfer fin plates 4A, 4B is formed by cutting and raising at different positions.

  In this way, the small-diameter heat transfer tube unit 4 is formed by bonding the two heat transfer fin plates 4A and 4B having the recessed groove portions for forming the tube portions 41a and 41b. 45a, 45a ..., 45b, 45b ..., 45c, 45c ... are formed by cutting and raising each of the two heat transfer fin plates 4A, 4B to be bonded together at different positions. As in the case of the third problem solving means, a large number of cut and raised pieces 45a, 45a..., 45b, 45b. Even when it is improved, the heat transfer area itself of the heat transfer fins 42a, 42b, 42c does not have to be reduced at all.

  Moreover, not only does it reduce, but rather the heat transfer area is expanded by the amount of cut and raised pieces 45a, 45a..., 45b, 45b.

  Therefore, the heat exchange performance can be more effectively improved without causing a decrease in fin efficiency.

  In addition, in the case of this configuration, the cut-and-raised pieces 45a, 45a ..., 45b, 45b ..., 45c, 45c ... for heat transfer promotion are on both sides of the heat transfer fins 42a, 42b, 42c. Therefore, the heat transfer promoting effect is further greatly improved.

(5) Fifth Problem Solving Means According to a fifth problem solving means of the present invention, in the configuration of the first problem solving means, the small-diameter heat transfer tube unit 4 includes tube portions 41a and 41b and the tube portions. It consists of heat transfer fin plates 42A, 42B, and 42C having a single plate structure that are caulked and fixed to both sides of 41a and 41b, and cut and raised pieces 45a, 45a, ..., 45b, 45b, ..., 45c, 45c ... · Is characterized by being formed by cutting and raising the heat transfer fin plates 42A, 42B, 42C of the single transfer plate structure.

  Thus, the small-diameter heat transfer tube unit 4 is composed of the heat transfer fin plates 42A, 42B, and 42C having a single plate structure that is fixed to both sides of the tube portions 41a and 41b and the tube portions 41a and 41b. The cut and raised pieces 45a, 45a ..., 45b, 45b ..., 45c, 45c ... are formed by cutting and raising the heat transfer fin plates 42A, 42B, 42C of the single plate structure. , 45b, 45b..., 45c, 45c... Are easy to form and each tube body portion 41a, 41b has a small passage cross-sectional area. 41a, 41b,..., 45b, 45b, 45c, 45c,... Through the opening formed inside Effectively becomes to flow by bypassing the next side of the passage opposite, more flow resistance is reduced. Therefore, the heat exchange performance can be improved more effectively.

(6) Sixth Problem Solving Means Sixth problem solving means of the present invention is the cut and raised pieces 45a, 45a in the first, second, third, fourth or fifth problem solving means. ..., 45b, 45b ..., 45c, 45c ... are characterized by being slits.

  Thus, when the cut and raised pieces 45a, 45a,..., 45b, 45b..., 45c, 45c. The operation of the fourth or fifth problem solving means is effectively realized.

(7) Seventh Problem Solving Means Seventh problem solving means of the present invention is the cut and raised pieces 45a, 45a in the first, second, third, fourth or fifth problem solving means. ..., 45b, 45b ..., 45c, 45c ... are louvers.

  In this way, when the cut and raised pieces 45a, 45a,..., 45b, 45b..., 45c, 45c. The operation of the fourth or fifth problem solving means is effectively realized.

(8) Eighth Problem Solving Means The eighth problem solving means of the present invention is the configuration of the first, second, third, fourth, fifth, sixth or seventh problem solving means. The exchanger is for a refrigeration apparatus such as an air conditioner, and the internal fluid is a mixed refrigerant containing 50 wt% or more of R32, a single refrigerant of R32, or a high-pressure refrigerant such as a CO ₂ refrigerant.

  According to the configuration of the first, second, third, fourth, fifth, sixth or seventh problem solving means, the fin efficiency is improved, and the heat transfer performance and the heat transfer efficiency are effectively improved.

Therefore, the heat exchanger is for a refrigeration apparatus such as an air conditioner, and the internal fluid is a mixed refrigerant containing 50 wt% or more of R32, or a single refrigerant of R32, or a high-pressure refrigerant such as a CO ₂ refrigerant. It is also suitable for a small-diameter heat transfer tube unit of a heat exchanger.

  As a result of the above, according to the present invention, it is possible to secure a sufficient area for conducting heat from the tube portion through which the internal fluid flows, and to effectively transfer heat by the cut and raised pieces without unduly reducing the fin efficiency. Promotion becomes possible.

  In addition, when slits are installed by cutting and raising only one plate on one or both sides of the bonded heat transfer fin plate, in addition to promoting heat transfer due to the leading edge effect, the heat transfer area itself also increases. Since it can be expected, the synergistic effect will further improve the performance of the heat exchanger.

(Best Embodiment 1)
First, FIG. 1 and FIG. 6 show the overall configuration of a small-diameter multi-tube heat exchanger constructed by adopting the small-diameter heat transfer tube unit according to the best embodiment 1 for carrying out the present invention. Yes.

  2 to 5 and 7 show the overall structure of the small-diameter heat transfer tube unit constituting the thin multi-tube heat exchanger and the structure of the main part.

  That is, first, a small-diameter multitubular heat exchanger 1 shown in FIG. 1 includes an inlet header 2A and an outlet header 2B having a refrigerant distribution function arranged in parallel with each other at a predetermined interval, and the inlet header 2A and the outlet A heat exchange section composed of thin heat transfer tube units (fined heat transfer tubes with fins) 4, 4... Connected to each of the headers 2 </ b> B and arranged on the lower side along the longitudinal direction. 3.

  As shown in FIG. 2, for example, the small-diameter heat transfer tube units 4, 4... 41d is connected to the respective openings on the bottom side of the inlet header 2A and the outlet header 2B, while the straight tube body portions 41a and 41b of the left and right rows of the U-shaped heat transfer tube 41 are connected to each other. In addition, fin portions 42a, 42b, and 42c having predetermined widths are provided on both the left and right sides (the fin portion 42b is common to both tube portions 41a and 41b). The two fin portions 42a, 42b, 42b, 42c on both sides of the straight tube portions 41a, 41b are continuous with each other to form one heat transfer fin 42 for the U-shaped heat transfer tube 41. .

  The small-diameter heat transfer tube units 4, 4... Having the heat transfer fins 42 each have a left-right symmetric structure having a semi-circular groove having a semicircular cross section for forming the heat transfer tubes 41 (tube portions 41 a, 41 b). These are formed by joining thin and flat vertically-long rectangular heat transfer fin plates (bonding members) 4A and 4B, for example, as shown in FIGS. Thus, small-diameter heat transfer tube units 4, 4... In which fin portions 42a, 42b, 42c are integrally formed on the left and right sides of the straight tube portions 41a, 41b of the U-shaped heat transfer tube 41 are configured. ing.

  The small-diameter heat transfer tube units 4, 4... Configured in this way are arranged in parallel at a predetermined fin pitch in parallel with the flow direction of the external fluid F, as shown in FIGS. In the same arrangement state, each small-diameter heat transfer tube unit 4, 4... Has an inlet header 2A and an outlet at the opening end portions 41c, 41d, 41d, 41c. The header 2B is connected, and finally a thin multi-tube heat exchanger 1 as shown in FIG. 1 is formed.

  According to such a configuration, the fin portions 42a, 42b, and 42c of the heat transfer fins 42 for further expanding the heat transfer area are provided on both sides of the tube portions 41a and 41b of the small-diameter heat transfer tube 41 that originally has a high heat transfer rate. In addition to the good heat transfer coefficient by the tube portions 41a, 41b of the small-diameter heat transfer tubes 41, 41..., The heat transfer area is greatly increased, and the overall heat exchange performance is improved. It greatly improves and is suitable for use conditions as a heat exchanger for a refrigerating apparatus such as an air conditioner.

  By the way, in the case of such a configuration, when the heat exchange section 3 is configured by arranging a plurality of small-diameter heat transfer tube units 4, 4... As shown in FIGS. If the heat transfer tube units 4, 4... Are arranged side by side in the same state, the tube portions 41a, 41b, 41a, 41b... Of the adjacent heat transfer tubes 41, 41. As a result, the ventilation resistance increases, so that the fin pitch is limited.

  On the other hand, in order to solve this problem, the positions of the heat exchangers 3 are simply shifted in the front-rear direction (upstream / downstream direction) in which the external fluid F flows and arranged in a staggered structure as a whole. Is not compact, and the positions of the opening end portions 41c, 41d, 41d, 41c,... For connection to the headers 2A, 2B are not aligned.

  Further, when the small-diameter heat transfer tube units 4, 4... Are arranged in a staggered structure as described above, the tube portions 41a, 41b, 41a, 41b. The tube portions 41a, 41b, 41a, 41b... And the fin surfaces of the fin portions 42a, 42b, 42c of the heat transfer fins 42 are adjacent to each other in the juxtaposed direction even if they are not adjacent to each other in the juxtaposed direction. Therefore, the passage interval through which the external fluid F flows is also narrower than the portion between the fin surfaces.

  Moreover, when it is going to improve the heat exchange performance of the above-mentioned small-diameter multi-tube heat exchanger as described above, as shown in FIGS. It is conceivable to provide cut and raised pieces 45a, 45a ..., 45b, 45b ..., 45c, 45c ... such as narrow slits and louvers.

  However, the fin portions 42b sandwiched between the tube portions 41a and 41b of the U-shaped heat transfer tube 41 through which the internal fluid flows are located at both ends, so the vertical direction is perpendicular to the flow direction of the external fluid F. When long slits 45a, 45a,... Are installed, the gap between them is small, and the number of gaps is very small. Therefore, there is a problem that heat from the tube portions 41a and 41b is not transmitted to the central portion of the fin portion 42b, fin efficiency is lowered, and a sufficient promotion effect cannot be obtained. Of course, this problem is the same in the fin portions 42a and 42c on the tube body portions 41a and 41b side, although there is a difference in size.

  Therefore, in this embodiment, as shown in FIGS. 3 to 5, first, one of the two straight tube portions 41a and 41b before and after the U-shaped heat transfer tube 41 (FIG. 2). In this example, the tube portion 41b on the downstream side is not linearly extended straight downward from the upper end side opening end portion 41c like the tube portion 41a on the other side, but instead of the heat transfer fin 42. By forming a crank-shaped bent portion R by forming the crank-shaped bent portion R in the center portion side (fin portion 42b side) once bent inward in a crank shape by a predetermined width a. Any one of the straight tube portions 41a and 41b of the heat transfer tube 41 is provided so as to be displaced to the left or right side of the heat transfer fin 42 as a whole.

  And, by arranging the small-diameter heat transfer tube units 4, 4... Configured in this way, for example, as shown in FIGS. The straight tube portions 41a, 41b, 41a, 41b,... Of each of the heat transfer tubes 41, 41,... Of the small-diameter heat transfer tube units 4, 4 ... are 41a, 41b, 41b, 41a, 41a. , 41b, 41b, and 41a are arranged side by side, and the predetermined dimension positions are shifted on the upstream side and the downstream side of the external fluid F, respectively, so that the arrangement of the staggered shape as a whole is made with respect to the flow direction of the external fluid F. Arranged in parallel.

  As a result, it is not necessary to shift the position of each of the small-diameter heat transfer tube units 4, 4... In the front-rear direction of the external fluid F, and the small-diameter heat transfer tube units adjacent in parallel to the flow direction of the external fluid F. The tube portions 41a, 41b, 41b, 41a, 41a, 41b, 41b, 41a,... Of the four, four heat transfer tubes 41, 41,. , And the distance between them increases, so that the flow resistance of the external fluid F is reduced, and the tube portions 41a, 41b, 41b, 41a, 41a, 41b of the heat transfer tubes 41, 41. ... and the heat transfer fins 42 (fin portions 42a, 42b, 42c), 42 (42a, 42b, 42c), ..., the external fluid F flows uniformly and smoothly.

  Therefore, the heat exchange performance can be effectively improved without enlarging the heat exchanger 3.

  In this embodiment, the fin portions 42a, 42b, 42c, 42a, 42b, 42c... Of the heat transfer fins 42, 42. As shown in FIG. 3, the cut and raised pieces 45a, 45a,..., 45b, 45b,. ... are provided.

  The cut and raised pieces 45a, 45a ..., 45b, 45b ..., 45c, 45c ... are provided in one row in the fin portion 42a, four rows in the fin portion 42b, and three rows in the fin portion 42c. The fin portions 42b and 42c are alternately arranged in a staggered manner for each row.

In the case of this embodiment, each of these cut and raised pieces 45a, 45a,..., 45b, 45b..., 45c, 45c. The fin plates 4A and 4B are formed by integrally cutting and raising both of them at the same position, and the inside of the cutting and raising part has openings penetrating the left and right sides of each of the fin parts 42a, 42b and 42c. parts are formed (width Y ₂ of the cut-and-raised pieces entering the interior during bonding is a little smaller than the width Y ₁ of the outer cut-and-raised piece).

  Therefore, a part of the contracted flow that bends and flows sideways at the tube portions 41a, 41b, 41a, 41b,... Of the heat transfer tubes 41, 41,. 45a, 45a ..., 45b, 45b ..., 45c, 45c ... through the opening of the forming part, effectively bypassing and flowing to the adjacent passage, The flow resistance is further reduced, and the heat transfer promoting function is greatly improved by the leading edge effect of the large number of cut and raised pieces 45a, 45a..., 45b, 45b.

  In addition, in the above configuration, the cut-and-raised pieces 45a, 45a ..., 45b, 45b ..., 45c, 45c ... of the slit structure provided on the fin surfaces of the heat transfer fins 42a, 42b, 42c are provided. , 45 b, 45 b, 45 c, 45 c, 45 b, 45 b, 45 c, 45 b, 45 b, 45 b, 45 b, 45 b, 45 b, 45 b, 45 b, 45 b, 45 b 45c: The gap area between the upper and lower sides is widened and increased, and heat from the tube parts 41a, 41b is surely conducted to the center or outer periphery according to the fin width of each of the fin parts 42a, 42b, 42c. A wide and uniform heat conduction region can be secured.

  That is, in the same configuration, as shown in FIG. 7, for example, a large number of cut and raised pieces 45a, 45a..., 45b, 45b. A large number of continuous fin surfaces are left in the periphery, and these become effective heat transfer paths from the tube portions 41a and 41b. Then, heat from the tube portions 41a and 41b is conducted uniformly and effectively through the heat transfer passage, as indicated by broken arrows in FIG.

  Therefore, without reducing the fin efficiency itself of the fin portions 42a, 42b, 42c of the heat transfer fin 42, a large number of cut and raised pieces 45a, 45a ..., 45b, 45b ..., 45c, 45c ... The effective heat transfer promoting function due to the leading edge effect can be more fully exhibited.

  As a result, the heat exchange performance of the heat exchanger 3 is also greatly improved.

(Modification)
In the above description, the slit structure is adopted as the cut and raised pieces 45a, 45a ..., 45b, 45b ..., 45c, 45c ... for promoting heat transfer. It may be of a structure.

  Thus, when the cut and raised pieces 45a, 45a ..., 45b, 45b ..., 45c, 45c ... are louvers, the same action as in the case of the slit is effectively performed by the louvers. Realized.

(Best Mode 2)
Next, FIGS. 8 and 9 show the structure of the small-diameter heat transfer tube unit of the small-diameter multitubular heat exchanger according to the second preferred embodiment for carrying out the present invention.

  In this configuration, a slit structure for promoting heat transfer similar to that provided in the heat transfer fins 42, 42... Of the small-diameter heat transfer tube units 4, 4. .., 45b, 45b..., 45c, 45c..., As described above, one of the two heat transfer fin plates 4A and 4B bonded together. It is characterized by being formed by cutting and raising only the side plate.

  In this way, the small-diameter heat transfer tube units 4, 4... Have two grooves having the groove portions 41 a, 41 b, 41 a, 41 b, etc. for forming the heat transfer tubes 41, 41. The heat fin plates 4A and 4B are bonded to each other, and the cut and raised pieces 45a, 45a,..., 45b, 45b,. Are formed by cutting and raising only one of the two heat transfer fin plates 4A and 4B, a plurality of cut and raised pieces 45a, 45a,. When the heat transfer promotion function is improved by forming 45c, 45c..., The heat transfer area itself of the fin portions 42a, 42b, 42c of the heat transfer fin 42 does not have to be reduced at all.

  Moreover, not only does it reduce, but rather the heat transfer area is expanded by the amount of cut and raised pieces 45a, 45a..., 45b, 45b.

  Therefore, the heat exchange performance can be more effectively improved without causing a decrease in fin efficiency.

(Best Mode 3)
Next, FIGS. 10 and 11 show the structure of the small-diameter heat transfer tube unit of the small-diameter multitubular heat exchanger according to the third preferred embodiment when the present invention is carried out.

  In this configuration, one side of the heat transfer fin plates 4A, 4B similar to those provided in the heat transfer fins 42, 42,... Of the thin-diameter heat transfer tube units 4, 4,. The heat transfer promotion slits 45a, 45a ..., 45b, 45b ..., 45c, 45c ... formed by the plates of the two heat transfer fin plates 4A, 4B bonded to each other. Each is formed on both sides by cutting and raising at different positions.

  As described above, the small-diameter heat transfer tube units 4, 4... Have two heat transfer fin plates 4A having the groove portions 41a, 41b. , 4B, and the cut and raised pieces 45a, 45a,..., 45b, 45b,. When the heat transfer fin plates 4A and 4B are cut and raised at different positions so as to be formed on both sides thereof, a large number of cut and raised pieces 45a, 45a ..., 45b, 45b ..., 45c, When the heat transfer promotion function is improved by forming 45c ..., the heat transfer area of the fin portions 42a, 42b, 42c of the heat transfer fin 42 is the same as in the case of the second embodiment. You don't have to reduce it.

  Moreover, not only does it reduce, but rather the heat transfer area is expanded by the amount of cut and raised pieces 45a, 45a..., 45b, 45b.

  Therefore, the heat exchange performance can be more effectively improved without causing a decrease in fin efficiency.

  Moreover, in the case of this configuration, the heat transfer promoting cut and raised pieces 45a, 45a..., 45b, 45b..., 45c, 45c. , 42c are provided on both sides, and the heat transfer promotion effect is further greatly improved.

(Modification)
In the above description, the slit structure is adopted as the cut and raised pieces 45a, 45a ..., 45b, 45b ..., 45c, 45c ... for promoting heat transfer. It may be of a structure.

  Thus, when the cut and raised pieces 45a, 45a ..., 45b, 45b ..., 45c, 45c ... are louvers, the same action as in the case of the slit is effectively performed by the louvers. Realized.

(Fourth Embodiment)
Next, FIG. 12 shows the structure of the small-diameter heat transfer tube unit of the small-diameter multi-tube heat exchanger according to the best embodiment 4 for carrying out the present invention.

  In this configuration, one side of the heat transfer fin plates 4A, 4B similar to those provided in the heat transfer fins 42, 42,... Of the thin-diameter heat transfer tube units 4, 4,. The heat transfer promoting slits 45a, 45a,..., 45b, 45b..., 45c, 45c.

  According to such waffle structure cut and raised pieces 45a, 45a,..., 45b, 45b..., 45c, 45c,. Since the leading edge effect occurs, the same effects as those of the above-described best embodiments 1 to 3 and best embodiment 4 can be obtained simultaneously.

(Best Mode 5)
Next, FIG. 13 shows the structure of the small-diameter heat transfer tube unit of the small-diameter multi-tube heat exchanger according to the best embodiment 5 for carrying out the present invention.

  In this configuration, the same small diameter heat transfer tube units 4, 4... As in the first to fourth embodiments described above are used as the tube portions 41 a, 41 b, 41 a, 41 b of the heat transfer tubes 41, 41. .. and heat transfer fin plates 42A, 42B, 42C having a single-plate structure that are caulked and fixed to the caulking portions 41e, 41f, 41e, 41f,... Of the tube portions 41a, 41b, 41a, 41b,. 42A, 42B, 42C, etc., and the cut and raised pieces 45a, 45a,..., 45b, 45b,. 42A, 42B, 42C, 42A, 42B, 42C,...

  As described above, the small-diameter heat transfer tube units 4, 4,... Are provided on both sides of the tube portions 41a, 41b, 41a, 41b, and the tube portions 41a, 41b, 41a, 41b,. The heat transfer fin plates 42A, 42B, 42C, 42A, 42B, 42C,..., Which are fixed to the U-shaped crimping portions 41e, 41f, are cut and raised pieces 45a, 45a,. .., 45b, 45b,..., 45c, 45c... Ruptures part of the heat transfer fin plates 42A, 42B, 42C, 42A, 42B, 42C. If formed by this, in addition to the same effects as those of the first to fourth embodiments, the cut and raised pieces 45a, 45a,..., 45b, 45b,. ., 45c, 45c ... The process itself is easy, and the cross-sectional area of the heat transfer tubes 41, 41,... Is reduced, and the shrinkage that flows to the side at the portions adjacent to the tube portions 41a, 41b, 41a, 41b,. A part of the flow passes through the opening formed by the cut and raised pieces 45a, 45a..., 45b, 45b..., 45c, 45c. Bypassing effectively, the flow resistance is further reduced.

  Therefore, the heat exchange performance can be improved more effectively.

(Modification)
In the above description, the slit structure is adopted as the cut and raised pieces 45a, 45a ..., 45b, 45b ..., 45c, 45c ... for promoting heat transfer. A structure may be used.

  Thus, when the cut and raised pieces 45a, 45a..., 45b, 45b..., 45c, 45c... Are louvers, the same action as in the case of the slits is effective by the louvers. To be realized.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an overall configuration of a thin multi-tubular heat exchanger according to the best embodiment 1 of the present invention. It is a perspective view of the small diameter heat exchanger tube unit which comprises the same small diameter multi-tube heat exchanger. It is a horizontal sectional view which shows the structure after bonding of the same small diameter heat exchanger tube unit. It is a figure which shows the structure of the opposing surface (bonding surface) before bonding of the right-and-left bonding members (a) and (b) of the same small-diameter heat transfer tube unit in comparison with right and left. It is a horizontal sectional view showing the composition before pasting of the same small diameter multi-tube heat exchanger. It is a horizontal sectional view which shows the structure of the heat exchanger part which consists of the same small diameter heat exchanger tube unit. It is an enlarged front view which shows the heat transfer effect | action of the principal part of the same small diameter heat exchanger tube unit. It is a horizontal sectional view which shows the structure of the thin diameter heat exchanger tube unit of the thin diameter multitubular heat exchanger which concerns on the best Embodiment 2 of this invention. It is a horizontal sectional view which shows the structure before bonding of the same small diameter heat exchanger tube unit. It is a horizontal sectional view which shows the structure of the thin diameter heat exchanger tube unit of the thin diameter multitubular heat exchanger which concerns on the best Embodiment 3 of this invention. It is a horizontal sectional view which shows the structure before bonding of the same small diameter heat exchanger tube unit. It is a horizontal sectional view which shows the structure of the principal part of the thin diameter heat exchanger tube unit of the thin diameter multitubular heat exchanger which concerns on the best Embodiment 4 of this invention. It is a partially notched perspective view which shows the structure of the principal part of the thin diameter heat exchanger tube unit of the thin diameter multitubular heat exchanger which concerns on the best Embodiment 4 of this invention. It is a perspective view which shows the whole structure of the thin diameter multitubular heat exchanger comprised using the conventional small diameter heat exchanger tube unit. It is a front view which shows the structure of the small diameter heat exchanger tube unit which comprises the same small diameter multi-tube heat exchanger. It is a horizontal sectional view (BB of Drawing 15) which shows the composition of the principal part of the thin diameter heat exchanger tube unit of the same small diameter multi-tube heat exchanger. It is a horizontal sectional view which shows the structure of the heat exchange part of the same small diameter multi-tube heat exchanger. It is a partial notch perspective view which shows the structure of the principal part of the improvement examination example of the small diameter heat exchanger tube unit of the conventional small diameter multi-tube heat exchanger. It is a partial front view which shows the structure of the heat-transfer fin surface which is the principal part of the same small diameter heat-transfer tube unit. It is a horizontal sectional view (CC of Drawing 19) showing the composition of the principal part of the same diameter heat exchanger tube unit.

Explanation of symbols

  1 is a thin multi-tube heat exchanger, 2A is an inlet header, 2B is an outlet header, 3 is a heat exchanger, 4 is a thin heat transfer tube unit, 41 is a U-shaped heat transfer tube of the thin heat transfer tube unit 4, 41a and 41b are straight tube portions of the U-shaped heat transfer tube 41, 42 is a heat transfer fin, 42a, 42b and 42c are fin portions, 45a, 45b and 45c are cut and raised pieces such as slits and louvers.

Claims (8)

  Narrow-diameter tube portions (41a) and (41b) for heat exchange between the internal fluid and the external fluid F, and heat transfer fins provided on both sides of the tube portions (41a) and (41b) ( A plurality of small-diameter heat transfer tube units (4), (4),... Composed of 42a), (42b), and (42c) are arranged in parallel with a predetermined interval in parallel with the direction in which the external fluid F flows. A small-diameter heat transfer tube unit of the small-diameter heat transfer tube heat exchanger, wherein the fin surfaces of the heat transfer fins (42a), (42b), (42c) have substantially square cut and raised pieces (45a), ( 45a) ..., (45b), (45b) ..., (45c), (45c) ..., a small diameter heat transfer tube unit of a small diameter multi-tube heat exchanger,   The small-diameter heat transfer tube unit (4) is formed by bonding two heat transfer fin plates (4A) and (4B) having concave grooves for forming the tube portions (41a) and (41b). The raised pieces (45a), (45a) ..., (45b), (45b) ..., (45c), (45c) ... are the two heat transfer fin plates to be bonded together ( 4. The small-diameter heat transfer tube unit of the small-diameter multi-tube heat exchanger according to claim 1, wherein both of 4A) and (4B) are integrally cut and raised at the same position.   The small-diameter heat transfer tube unit (4) is formed by bonding two heat transfer fin plates (4A) and (4B) having concave grooves for forming the tube portions (41a) and (41b). The raised pieces (45a), (45a) ..., (45b), (45b) ..., (45c), (45c) ... are the two heat transfer fin plates (4A) to be bonded together. ), (4B) is formed by cutting and raising only one of the sides, and the small diameter heat transfer tube unit of the small diameter multitubular heat exchanger according to claim 1.   The small-diameter heat transfer tube unit (4) is formed by bonding two heat transfer fin plates (4A) and (4B) having concave grooves for forming the tube portions (41a) and (41b). The raised pieces (45a), (45a) ..., (45b), (45b) ..., (45c), (45c) ... are the two heat transfer fin plates to be bonded together ( 4. The small diameter heat transfer tube unit of the small diameter multitubular heat exchanger according to claim 1, wherein each of 4A) and (4B) is formed by cutting and raising at different positions.   A heat transfer fin plate (42A) having a single plate structure in which the small-diameter heat transfer tube unit (4) is crimped and fixed to both sides of the tube portions (41a) and (41b) and the tube portions (41a) and (41b). ), (42B), (42C), and the cut and raised pieces (45a), (45a) ..., (45b), (45b) ..., (45c), (45c) ... The heat transfer fin plate (42A), (42B), (42C) of the said 1 sheet board structure is formed by cutting and raising, The small diameter multitubular heat exchanger of Claim 1 characterized by the above-mentioned. Small diameter heat transfer tube unit.   The cut and raised pieces (45a), (45a) ..., (45b), (45b) ..., (45c), (45c) ... are slits. A thin heat transfer tube unit of the thin multi-tube heat exchanger according to 2, 3, 4 or 5.   The cut and raised pieces (45a), (45a) ..., (45b), (45b) ..., (45c), (45c) ... are louvers. A thin heat transfer tube unit of the thin multi-tube heat exchanger according to 2, 3, 4 or 5. The heat exchanger is for a refrigeration apparatus such as an air conditioner, and the internal fluid is a mixed refrigerant containing 50 wt% or more of R32, a single refrigerant of R32, or a high-pressure refrigerant such as a CO ₂ refrigerant. Item 8. A thin-diameter heat transfer tube unit of a thin-diameter multitubular heat exchanger according to item 1, 2, 3, 4, 5, 6 or 7.

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