JP2006084067A - Thin heating tube unit for thin multitubular heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve sealing performance of fin joint faces by effectively performing degasification similar as that by substantially narrowing a fin width, without actually narrowing the fin width by forming opening parts such as a slit on an outer periphery of a tube body part of a thin heating tube unit. <P>SOLUTION: In this thin heating tube unit 4 of a thin multitubular heat exchanger composed of the thin tube body parts 41, 41a, 41b exchanging heat between inner fluid and outer fluid, and heat transfer fins 42, 42a, 42b mounted on the tube body parts 41, 41a, 41b, the opening parts 43a, 43b such as slits penetrated through both face sides of the fins are formed on the heat transfer fin parts 42, 42a, 42b. According to this constitution, as the effective degasification similar as that by narrowing the fin width, can be substantially performed by the presence of the opening parts 43a, 43b such as the slits penetrated through both face sides of the heat transfer fins 42, 42a, 42b, the sealing performance and pressure tightness of the fin joint faces can be effectively improved. <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. The tube is arranged such that the pitch L between the tubes is about the tube diameter d to 2d of the tube to form a core portion through which an external fluid flows, and the plurality of tubes of the core portion are further flowed through 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, although it is good when the cooling water which does not change a phase state like the radiator of a car shown in patent documents 1 is made into an internal fluid, the refrigerant which changes a phase state like the above-mentioned air conditioner is made into an internal fluid. In that case, it was difficult to adopt.

  Therefore, based on such circumstances, a thin fin-like fin portion is added to each tubular body portion of the above-described small-diameter heat transfer tube, and the specification conditions of each tubular body portion and the fin portion are made less prone to drift. By forming, it is possible to effectively increase the heat transfer area in addition to the heat transfer coefficient, and to provide a small-diameter multi-tube heat exchanger that can be effectively used in air conditioners and the like. It has been.

  An example of the structure 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. 11 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...

  The small-diameter heat transfer tube units 4, 4... Have, as shown in FIG. 12 and FIG. While the opening end portions 41c and 41d are respectively connected to the respective opening portions on the bottom side of the inlet header 2A and the outlet header 2B, the straight portions 41a and 41b of the U-shaped tubular body portion 41 include Fin portions 42a and 42b having predetermined widths are provided respectively on the upstream side and the downstream side of the left and right air flows. These fin portions 42a and 42b are continuous with each other, and form one heat transfer fin 42 with respect to the U-shaped tube portion 41 in appearance.

  And the small-diameter heat transfer tube units 4, 4... Having the heat transfer fins 42 are respectively formed with tube portions 41 (41 a, 41 b) as shown in FIGS. The thin and flat fin plates (bonding members) (a) and (b) having a concave groove portion having a semicircular cross section for use are bonded in a state of facing each other as shown in FIG. To form the small-diameter heat transfer tube units 4, 4... In which the fin portions 42a, 42b are integrally formed on the left and right sides of the straight portions 41a, 41b of the U-shaped tube body portion 41. ing.

  The small-diameter heat transfer tube units 4, 4... Configured as described above are arranged in parallel to the flow direction of the external fluid F as shown in FIG. The inlet header 2A and the outlet header 2B are connected to the opening 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, heat transfer fins for further expanding the heat transfer area are provided on both sides of the tube body portion 41 (41a, 41b) of a large number of small-diameter heat transfer tubes with originally high heat transfer rates. 42 (42a, 42b) is added, in addition to the good heat transfer coefficient by the tube portions 41, 41... (41a, 41b, 41a, 41b...) Of a plurality of small diameter heat transfer tubes. As a result, the heat transfer area is also greatly increased, the overall heat exchange performance is greatly improved, and it is suitable for use conditions as a heat exchanger for an air conditioner.

  Further, in the case of the above configuration, when the heat exchange unit 3 is configured by arranging the small-diameter heat transfer tube units 4, 4... As shown in FIG. 14, the tube portions 41, 41. 41b, 41a, 41b...) Are close to each other, the ventilation resistance is increased, and the fin pitch is limited. Therefore, in order to solve such a problem, for example, as shown in FIG. 15, it is possible to alternately change the position in the front-rear direction in which the external fluid F flows, and to arrange the staggered structure as a whole.

  According to such a configuration, the tube portions 41, 41... (41a, 41b, 41a, 41b...) Of the small-diameter heat transfer tube units 4 and 4 adjacent in parallel to the flow direction are external fluids F. Are displaced by a predetermined dimension in the flow direction and the distance between them is widened, so that the flow resistance of the external fluid F is reduced, and the tube portions 41, 41... (41a, 41b, 41a, 41b,. ..) and heat transfer fins 42, 42... (42a, 42b, 42a, 42b. Therefore, the heat exchange performance is further improved.

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

  By the way, in the case of the above structure, the bonding of the two fin plates (bonding members) shown in FIGS. 13A and 13B is temporarily fixed by caulking or laser welding, and then the atmosphere This is done by brazing in the furnace in the furnace.

  For this reason, in order to improve the sealing performance of the joint and prevent leakage of the refrigerant or the like, it is necessary to effectively and uniformly leak the flux gas generated between the joint surfaces during the joint.

  However, in the case of the configuration as shown in FIGS. 11 to 15, the heat transfer fins 42 (parts where the fin portions 42 a and 42 b are combined), compared to the tube diameter φ of the thin-diameter tube body portion 41 (41 a, 41 b). ) Since the width W of the portion is considerably large, the area of the joint surface is large, and it is difficult to degas the above-described flux gas.

  Therefore, improvement of the sealing performance and pressure resistance of the joint surface is a problem.

  In order to improve this, for example, brazing sheets may be frequently used and brazed in a furnace in a vacuum furnace. However, doing so increases the cost and complicates the process of brazing in the furnace.

  The present invention has been made on the basis of such circumstances, and the fin width is actually narrowed by providing openings such as slits in the fin portion on the outer periphery of the tube portion of the above-described small-diameter heat transfer tube unit. A thin heat transfer tube unit for a thin multi-tubular heat exchanger that can effectively remove gas as if the fin width is substantially narrowed and improves the sealing performance of the fin joint surface is provided. It is for the purpose.

  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 thin tube portion 41, 41a, 41b that allows heat exchange between an internal fluid and an external fluid, and the tube portion. In the small-diameter heat transfer tube unit 4 of the small-diameter multi-tube heat exchanger comprising heat transfer fins 42, 42a, 42b provided on the outer periphery of 41, 41a, 41b, ..., the heat transfer fins 42, 42a, 42b Further, the heat transfer fins 42, 42a and 42b are formed with openings penetrating on both sides.

  According to such a configuration, the presence of the openings penetrating the both sides of the heat transfer fins 42, 42a, 42b enables effective degassing similar to the fact that the fin width is actually narrowed. The sealing performance and pressure resistance of the fin joint surface can be improved.

(2) Second Problem Solving Means The second problem solving means of the present invention is characterized in that, in the configuration of the first problem solving means, the opening is formed by slits 43a and 43b.

  With such a configuration, the heat transfer function (area) of the heat transfer fins 42, 42a, 42b as effective as possible can be ensured while obtaining a sufficient gas venting action by the slits 43a, 43b.

(3) Third Problem Solving Means The third problem solving means of the present invention is that, in the configuration of the second problem solving means, the slits 43a, 43b are a plurality of slits 43a, 43b, 43a separated from each other. , 43b...

  In this way, uniform gas venting is possible over the entire fin surface of the heat transfer fins 42, 42a, 42b in which a plurality of slits for venting gas are formed, while each slit has a plurality of 43a, 43b, 43a, 43b... Are separated from each other, it is possible to ensure effective fin performance and sufficient fin strength.

(4) Fourth Problem Solving Means According to a fourth problem solving means of the present invention, in the configuration of the second problem solving means, the slits 43a and 43b are formed in the longitudinal direction of the heat transfer fins 42, 42a and 42b. It is characterized by being.

  As described above, when the slits 43a and 43b are formed in the longitudinal direction of the heat transfer fins 42, 42a and 42b, the degassing region can be formed wider along the fin longitudinal direction. Degassing effect and sealing performance are improved.

(5) Fifth Problem Solving Means The fifth problem solving means of the present invention is that the slits 43a, 43b are the widths of the heat transfer fins 42, 42a, 42b,. It is characterized by being formed in the direction.

  Thus, when the slits 43a and 43b are formed in the width direction of the heat transfer fins 42, 42a and 42b, the heat transfer performance of the fin portion including the leading edge effect can be effectively ensured, and the fins The strength of the part is also increased.

(6) Sixth Problem Solving Means The sixth problem solving means of the present invention is that, in the configuration of the second problem solving means, the slits 43a, 43b are predetermined in the width direction of the heat transfer fins 42, 42a, 42b. It is characterized by being formed at an angle.

  As described above, when the slits 43a and 43b are formed to be inclined at a predetermined angle in the width direction of the heat transfer fins 42, 42a and 42b, the length of the slits 43a and 43b can be increased by the inclination angle. In addition, the heat transfer performance of the fin portion including the leading edge effect can be more effectively ensured, and the strength of the fin portion is also increased.

(7) Seventh Problem Solving Means According to a seventh problem solving means of the present invention, in the configuration of the fourth problem solving means, a plurality of slits 43a, 43b in the longitudinal direction of the heat transfer fins 42, 42a, 42b are provided. It is characterized in that it is provided at a position corresponding to the adjacent tube parts 41, 41a, 41b when the sheets are arranged side by side.

  In this way, when the slits 43a and 43b in the fin longitudinal direction are formed at positions corresponding to the tube portions 41, 41a and 41b of the adjacent heat transfer tubes, the slits 43a and 43b absorb the bending of the wind caused by the heat transfer tube convex portions. Bypassing, passage resistance is reduced, and as a result, heat exchange performance is improved.

(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, a predetermined width is provided on both sides of the tube portions 41, 41a, 41b of the small-diameter heat transfer tubes. In the small-diameter heat transfer tube unit 4 having a bonded structure including the heat transfer fins 42, 42a, 42b, the high sealing performance of the heat transfer fins 42, 42a, 42b can be maintained, and the high pressure performance can be improved. be able to.

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. This is suitable for small-diameter heat transfer tube units of heat exchangers.

  As a result, according to the present invention, it is possible to improve the degassing of the fin joint and improve the sealing performance of the joint.

Therefore, it is possible to effectively cope with 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, and the heat exchange performance can be improved.

(Best Embodiment 1)
1 to 4 show the structure of a small-diameter heat transfer tube unit of a small-diameter multi-tube heat exchanger according to the best embodiment 1 for carrying out the present invention.

  FIG. 5 and FIG. 6 show the configuration of a small-diameter multi-tube heat exchanger configured by adopting the small-diameter heat transfer tube unit having the same structure.

  That is, first, a small-diameter multitubular heat exchanger 1 shown in FIG. 5 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 FIGS. 1 and 2, for example, the small-diameter heat transfer tube units 4, 4,... Have a tubular portion (thin-diameter tube portion) 41 of the heat transfer tube bent in a U shape as a whole. The upper end opening portions 41c and 41d are connected to the bottom opening portions of the inlet header 2A and the outlet header 2B, respectively, while the left and right straight portions 41a of the U-shaped tube portion 41 are connected. , 41b are respectively provided with fin portions 42a, 42b having predetermined widths located on the left and right sides thereof. The fin portions 42a and 42b on both sides of the straight portions 41a and 41b are continuous with each other to form one heat transfer fin 42 for the U-shaped tube portion 41.

  And the small diameter heat-transfer tube unit 4,4 ... provided with this tube part 41 (41a, 41b) and the heat-transfer fin 42 (42a, 42b) is shown to (a), (b) of FIG. As shown, thin and flat vertically elongated rectangular fin plates 4A and 4B each having a semi-circular groove having a semicircular cross section for forming a tubular body portion 41 (41a and 41b) are shown in FIGS. As shown in FIG. 3, the fin portions 42a and 42b are integrally formed on both the left and right sides of the straight portions 41a and 41b of the tube portion 41. The small-diameter heat transfer tube units 4, 4.

  The small-diameter heat transfer tube units 4, 4... Configured as described above are arranged in parallel at a predetermined pitch in parallel with the flow direction of the external fluid F, for example, as shown in FIG. In the same arrangement state, the inlet header 2A and the outlet header 2B are connected to the opening end portions 41c, 41d, 41d, 41c. Finally, a thin multi-tube heat exchanger 1 as shown in FIG. 5 is formed.

  According to such a configuration, the heat transfer fins 42 (42a, 42a, 41a, 41a, 41b, 42a, 41a, 41b) are further provided on both sides of the tube portion 41 (41a, 41b, 41a, 41b) of the small-diameter heat transfer tube having a high heat transfer rate. 42b) is added, in addition to the good heat transfer coefficient by the tube portion 41 (41a, 41b) of the small diameter heat transfer tube, the heat transfer area is also greatly increased, and the overall heat exchange performance is increased. It improves and becomes suitable for the use conditions as a heat exchanger for an air conditioner.

  By the way, in the case of such a configuration, when the heat exchange unit 3 is configured by arranging a plurality of small-diameter heat transfer tube units 4, 4... As shown in FIG. If each of them is arranged side by side, the adjacent tube body parts 41 (41a, 41b) and 41 (41a, 41b) are close to each other as in the case of FIG. The pitch also has a limit. On the other hand, in order to solve this problem, for example, as shown in FIG. 15 described above, if the positions are alternately changed in the front-rear direction in which the external fluid F flows and arranged in a zigzag structure as a whole, Are not compact and the positions of the connecting opening end portions 41c, 41d, 41d, 41c,...

  Therefore, in this embodiment, for example, as shown in FIGS. 1 to 4, one of the two straight portions 41 a and 41 b of the U-shaped tube body portion 41 is replaced with its upper end opening end. Rather than linearly extending downward from the portion 41d, the U-shaped portion is formed by bending the heat transfer fin 42 into the crank shape R once by a predetermined width a on the center side of the heat transfer fin 42 and extending downward. The tubular body portion 41 (41a, 41b) is configured to be provided in a deviated form on the left or right side of the heat transfer fin 42 as a whole.

  In this state, the heat transfer fin 42 further includes a heat transfer fin between the two straight portions 41a and 41b of the tube portion 41 of the heat transfer fin 42 and the outer peripheral side center of the straight portion 41b bent in a crank shape R. Two slits 43a and 43b having the same width as the outer diameter of the tubular body portion 41 (41a and 41b) are provided as openings penetrating the both surfaces of 42.

  In addition, each of the small-diameter heat transfer tube units 4, 4... Configured as described above is arranged in parallel with the left and right directions being alternately reversed, as shown in FIGS. The flow of the external fluid F so that the straight portions 41a, 41b, 41a, 41b ... of the tube portions 41, 41 ... of the radial heat transfer tube units 4, 4 ... are arranged in a staggered manner as a whole. Arranged parallel to the direction.

  As a result, it is not necessary to shift the position of each of the small-diameter heat transfer tube units 4, 4. Since the pipe portions 41 (41a, 41b), 41 (41a, 41b)... Themselves are displaced by a predetermined dimension upstream and downstream in the flow direction of the external fluid F, and the distance between them increases, the external fluid F The flow path resistance of the tube portions 41 (41a, 41b), 41 (41a, 41b)... And the heat transfer fins 42 (42a, 42b), 42 (42a, 42b). Flows evenly and smoothly on the surface. Accordingly, the heat exchange performance is further improved without enlarging the heat exchanger 3.

  Further, in the case of the above-described configuration, the two fin plates (bonding members) 4A and 4B shown in FIGS. 4A and 4B are temporarily fixed by caulking or laser welding. And then brazing in a furnace in an atmospheric furnace.

  For this reason, in order to improve the sealing performance of the joint and prevent leakage of the refrigerant or the like, it is necessary to effectively and uniformly leak the flux gas generated between the joint surfaces during the joint.

  However, in the case of the configuration as shown in FIGS. 1 to 4, the heat transfer fins 42 (parts where the fin portions 42 a and 42 b are combined) as compared with the tube diameter φ of the small-diameter tube body 41 (41 a, 41 b). ) Since the width W of the portion is considerably large, the area of the joint surface is large, and it is difficult to degas the above-described flux gas. Therefore, improvement of the sealing performance and pressure resistance of the joint surface is a problem.

  In order to improve this, for example, brazing sheets may be frequently used and brazed in a furnace in a vacuum furnace. However, doing so increases costs and complicates the process of brazing in the furnace.

  Therefore, in this embodiment, two slits 43a and 43b extending in the vertical direction as openings penetrating the heat transfer fins 42 (42a, 42b), 42 (42a, 42b). ... the opening part which consists of is formed.

  Therefore, according to such a configuration, the fin width is actually reduced by the slits 43a, 43b... Penetrating through both sides of the heat transfer fins 42 (42a, 42b), 42 (42a, 42b). Effective degassing similar to the narrowing is possible, and the sealing performance and pressure resistance of the fin joint surface can be improved effectively.

Therefore, for example, it is possible to effectively cope with a mixed refrigerant (R410A) containing 50 wt% or more of R32, a single refrigerant of R32, or a high-pressure refrigerant such as a CO ₂ refrigerant, and the heat exchange performance is improved. be able to.

  In the same configuration, as described above, the slits 43a and 43b for venting are formed over substantially the entire length of the heat transfer fins 42 (42a, 42b), 42 (42a, 42b). Therefore, the heat transfer fins 42 (42a, 42b), 42 (42a, 42b)... Can be uniformly vented over the entire surface, while each of these slits has an effective leading edge effect. Therefore, the heat exchange performance is further improved.

  Further, in the case of the above configuration, as is apparent from FIG. 6, the slits 43a, 43b are formed so that the tube portions 41 (41a, 41b), 41 () of the adjacent small-diameter heat transfer tube units 4, 4,. 41a, 41b)...

  Therefore, a part of the air flow that bends and flows laterally at each tubular body portion 41 (41a, 41b), 41 (41a, 41b)... Portion passes through the slits 43a and 43b to the adjacent passage. Also flows by bypass, the flow resistance is further reduced, and the leading edge effect is further improved.

(Best Mode 2)
Next, FIG. 7 shows the structure of the small-diameter heat transfer tube unit of the small-diameter multi-tube heat exchanger according to the second preferred embodiment when the present invention is implemented.

  In the configuration of this embodiment, the gas vent slits 43a, 43b,... In the configuration of the best embodiment 1 described above are divided into two slits 43a, 43b, 43a, 43b in the vertical direction. It is characterized by being divided.

  In this way, when the slit for degassing is divided into two slits 43a, 43a, 43a, 43b,... Upper and lower, the heat transfer fins 42 (42a, 42b).・ ・ Although uniform degassing is possible over the entire fin surface, effective fin performance and sufficient fin strength can be ensured.

(Best Mode 3)
Next, FIG. 8 shows the structure of a small-diameter heat transfer tube unit of a small-diameter multitubular heat exchanger according to the third preferred embodiment for carrying out the present invention.

  In the configuration of this embodiment, the gas vent slits 43a and 43b in the configuration of the best embodiment 1 are further replaced with four slits 43a, 43b, 43a, 43b, 43a, It is characterized by being divided into 43b.

  As described above, when the slit for venting is further divided into the upper and lower slits 43a, 43b, 43a, 43b, 43a, 43b, 43a, 43b, the heat transfer fins 42 are formed. While uniform gas venting is possible over the entire fin surfaces of (42a, 42b), more effective fin performance and more sufficient fin strength can be ensured.

(Fourth Embodiment)
Next, FIG. 9 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 the configuration of this embodiment, the gas vent slits 43a and 43b in the configuration of the best embodiment 1 described above extend in the width direction of the heat transfer fins 42 (42a and 42b), and the heat transfer fins 42 ( 42a, 42b) is divided into a plurality of slits 43a, 43b, 43a, 43b,... Arranged in parallel in the vertical direction.

  As described above, when the slits for venting the gas are formed by dividing the slits 43a, 43b, 43a, 43b in the vertical direction of the heat transfer fins 42 (42a, 42b), the heat transfer fins 42 ( 42a, 42b) can be uniformly vented over the entire fin surface, while more effective fin performance and sufficient fin strength can be ensured.

  Further, it is not necessary to completely divide the fin function as the entire heat transfer fin 42 at the front edge side and the rear edge side, and the entire heat transfer fin 42 can effectively contribute to heat exchange.

(Best Mode 5)
Next, FIG. 10 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 the configuration of this embodiment, a plurality of gas vent slits 43a, 43b, 43a, 43b,... In the width direction of the heat transfer fins 42 (42a, 42b) in the configuration of the best embodiment 4 are provided. Each of them is provided to be inclined at a predetermined angle in the vertical direction.

  As described above, when the gas vent slits 43c, 43c,... Are formed at a predetermined angle in the width direction of the heat transfer fins 42 (42a, 42b), the slits 43a, 43b, 43a, 43b are formed. Can be formed longer by the inclination angle, the heat transfer performance of the fin portion including the leading edge effect can be effectively ensured, and the strength of the fin portion is also increased.

  Further, it is not necessary to completely divide the fin function as the entire heat transfer fin 42 at the front edge side and the rear edge side, and the entire heat transfer fin 42 can effectively contribute to heat exchange.

It is a perspective 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 1 of this invention. It is an expansion perspective view of the principal part of the same small diameter heat exchanger tube unit. It is sectional drawing (AA of FIG. 1) of the same small diameter heat exchanger tube unit. It is a figure which shows the structure of the opposing surface (joining surface) before bonding of the right-and-left bonding member of the same small diameter heat-transfer tube unit as compared with right and left. It is a perspective view of the thin diameter multi-tube heat exchanger comprised using the same thin diameter heat exchanger tube unit. 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 perspective 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 perspective 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 perspective 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 4 of this invention. It is a perspective 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 5 of this invention. It is a perspective view which shows the structure of the small diameter multitubular heat exchanger comprised using the conventional small diameter heat exchanger tube unit. It is a figure which shows the structure of the opposing surface (joining surface) before bonding of the right-and-left bonding member of the small-diameter heat-transfer tube unit which comprises the same small diameter multi-tube heat exchanger as compared with right and left. It is a horizontal sectional view which shows the structure of the thin diameter heat exchanger tube unit part of the same thin 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 horizontal sectional view which shows the structure of the modification of the heat exchanger part of the same small diameter multi-tube heat exchanger.

Explanation of symbols

  1 is a thin multi-tubular heat exchanger, 2A is an inlet header, 2B is an outlet header, 3 is a heat exchanger, 4 is a small diameter heat transfer tube unit, and 41 is a U-shaped tube portion of the small diameter heat transfer tube unit 4 , 41a and 41b are straight portions of the tube portion 41, 42 is a heat transfer fin, 42a and 42b are fin portions, and 43a and 43b are slits.

Claims (8)

  Narrow diameter tube sections (41), (41a), (41b) and the tube sections (41), (41a), (41b), etc. for exchanging heat between the internal fluid and the external fluid. In the small-diameter heat transfer tube unit (4) of the small-diameter multi-tube heat exchanger comprising the heat transfer fins (42), (42a), (42b) provided on the outer periphery of the heat transfer fins (42), ( 42a) and (42b) are formed with openings penetrating on both sides of the heat transfer fins (42), (42a) and (42b). Heat tube unit.   2. The small-diameter heat transfer tube unit of a thin multi-tube heat exchanger according to claim 1, wherein the opening includes slits (43a) and (43b).   The slit (43a), (43b) is composed of a plurality of slits (43a), (43b)... Separated from each other. Radial heat transfer tube unit.   The small-diameter multitubular heat exchanger according to claim 2, wherein the slits (43a), (43b) are formed in the longitudinal direction of the heat transfer fins (42), (42a), (42b). Small diameter heat transfer tube unit.   The small-diameter multitubular heat exchanger according to claim 2, wherein the slits (43a), (43b) are formed in the width direction of the heat transfer fins (42), (42a), (42b). Small diameter heat transfer tube unit.   The slits (43a) and (43b) are formed with a large angle and a slant at a predetermined angle in the width direction of the heat transfer fins (42), (42a) and (42b). Small-diameter heat transfer tube unit for tube heat exchangers.   The slits (43a), (43b) in the longitudinal direction of the heat transfer fins (42), (42a), (42b) are adjacent to the tubular body portions (41), (41a), ( The small-diameter heat transfer tube unit of the small-diameter multitubular heat exchanger according to claim 4, wherein the thin-diameter heat transfer tube unit is provided at a position corresponding to 41b). 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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