JP2006112732A

JP2006112732A - Small-diameter heat transfer tube unit of small-diameter multitubular heat exchanger

Info

Publication number: JP2006112732A
Application number: JP2004301507A
Authority: JP
Inventors: Hirokazu Fujino; 宏和藤野; Takayuki Takahashi; 孝幸高橋; Keiji Ashida; 圭史芦田; Haruo Nakada; 春男中田
Original assignee: Daikin Industries Ltd
Current assignee: Daikin Industries Ltd
Priority date: 2004-10-15
Filing date: 2004-10-15
Publication date: 2006-04-27

Abstract

PROBLEM TO BE SOLVED: To provide a small-diameter heat transfer tube unit capable of remarkably improving heat exchanging performance, having good appearance, and improving the rigidity of a heat transfer fin end face to prevent deformation and to keep an effective airflow rate. SOLUTION: The width W1 of a heat transfer fin 42c or 42a positioned on the outer peripheral side of one of the heat transfer tubes 41b, 41a longitudinally arranged in two lines is formed larger than the width W2 of the heat transfer fin 42a or 42b positioned on the outer peripheral side of the heat transfer tube 41a or 41b of the other side, thus end faces on the upstream side and the downstream side of external fluids of the heat transfer fins 42a, 42b, 42c, 42c, 42b, 42a, ... can be aligned in a flush state. COPYRIGHT: (C)2006,JPO&NCIPI

Description

本願発明は、細径多管式熱交換器の細径伝熱管ユニットの構造に関するものである。 The present invention relates to a structure of a small-diameter heat transfer tube unit of a small-diameter multi-tube heat exchanger.

最近では、例えば所定の間隔を置いて対向配置された入口タンクと出口タンクとの間に、管径ｄが０．２ｍｍ〜０．８ｍｍ程度の細径の断面円環状の複数のチューブを、当該各チューブ間のピッチＬが上記チューブの管径ｄ〜２ｄ程度となるよう配置して外部流体が流通するコア部を形成するとともに、さらに上記コア部の複数のチューブをコア部の外部流体の流れ方向に正方形の碁盤目状に配置し、外部流体との接触効率を向上させた細径多管式の伝熱管構造を採用した熱交換器が提案されている（例えば特許文献１参照）。 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).

このような細径多管式の熱交換器は、空気調和機などの熱交換器として一般的に使用されているフィン・アンド・チューブ型の熱交換器に比較して、より高性能で、より通風抵抗が小さいので、高効率の熱交換器として機能させることが可能である。 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.

しかし、このような細径多管式熱交換器の構成の場合、コア部が細径伝熱管の集合体よりなるために伝熱管熱交部トータルとしての熱伝達率そのものは高いが、他方各伝熱管個々の伝熱面積が小さいために、一定レベル以上の高性能化を図るためには、より多数本の細径伝熱管が必要となる。その結果、構造が複雑で、組み立ても煩雑となる。 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.

また、同細径の伝熱管群は、外部流体（空気）の流れ方向に多数本の流路を碁盤目状に設けて内部流体（水）を流すようになっているが、その流れ方向の位置によって各流路毎の熱交換量が異なるために偏流を生じやすく、特に空気調和機のように気液二相冷媒を流す場合にはその傾向が著しい。 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.

したがって、特許文献１に示される自動車のラジエータのような相状態が変化しない冷却水を内部流体とする場合には良いが、上記空気調和機などのように相状態が変化する冷媒を内部流体とする場合には、採用することが困難であった。 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.

そこで、このような事情に基き、上述の細径の伝熱管の各管体部に薄板状のフィン部を付加するとともに、それら各管体部およびフィン部の仕様条件を偏流を生じにくいものに形成することによって、熱伝達率に加えて、伝熱面積をも有効に増大させ、空気調和機などにも有効に採用できるようにした細径多管式の熱交換器を提供することが考えられている。 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.

この伝熱フィンを備えた細径多管式熱交換器および同細径多管式熱交換器を構成する細径伝熱管ユニットの構成の一例を図９〜図１３に示す。 An example of the structure of the thin diameter multi-tube heat exchanger provided with this heat transfer fin and the small diameter heat transfer tube unit constituting the same thin diameter multi-tube heat exchanger is shown in FIGS.

すなわち、先ず図９に示す細径多管式熱交換器１は、相互に所定の間隔を保って並設された冷媒分配機能を有する入口ヘッダ２Ａおよび出口ヘッダ２Ｂと、該入口ヘッダ２Ａと出口ヘッダ２Ｂの各々に接続され、その下部側に位置して長手方向に沿って多数本並設された細径伝熱管ユニット４，４・・・よりなる熱交部３とから構成されている。 That is, first, a small-diameter multi-tube heat exchanger 1 shown in FIG. 9 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...

上記細径伝熱管ユニット４，４・・・は、例えば図１０及び図１１に示すように、その伝熱管（細径管）４１が全体としてＵ状に曲成され、その上端側各開口端部４１ｃ，４１ｄが上記入口ヘッダ２Ａ、出口ヘッダ２Ｂの底部側各開口部に各々接続されるようになっている一方、同Ｕ状の伝熱管４１のストレートな管体部４１ａ，４１ｂには、それぞれ左右両側空気流の上流側と下流側に位置して各々所定の幅のフィン部４２ａ，４２ｂ，４２ｃが設けられている（フィン部４２ｂは管体部４１ａ，４１ｂに共通）。これらフィン部４２ａ，４２ｂ，４２ｃは相互に連続して、外見上は上記Ｕ状の伝熱管４１の管体部４１ａ，４１ｂに対して１枚の伝熱フィン４２を形成している。 As shown in FIGS. 10 and 11, for example, the small-diameter heat transfer tube units 4, 4... While the portions 41c and 41d are respectively connected to the openings on the bottom side of the inlet header 2A and the outlet header 2B, the straight tube portions 41a and 41b of the U-shaped heat transfer tube 41 Fin portions 42a, 42b, and 42c each having a predetermined width are provided respectively on the upstream side and the downstream side of the left and right air flows (the fin portion 42b is common to the tube portions 41a and 41b). These fin portions 42a, 42b, 42c are continuous with each other, and form one heat transfer fin 42 with respect to the tube portions 41a, 41b of the U-shaped heat transfer tube 41 in appearance.

そして、該伝熱フィン４２を備えた細径伝熱管ユニット４，４・・・は、例えば図１０の（ａ），（ｂ）に示すように、それぞれ伝熱管４１（管体部４１ａ，４１ｂ）形成用の断面半円形状の凹溝部を有する左右対称構造の薄くて扁平な伝熱フィンプレート（貼り合わせ部材）（ａ），（ｂ）を、例えば図１１のように相互に対向させた状態で、接合して一体化することにより、上記Ｕ状の伝熱管４１のストレートな管体部４１ａ，４１ｂの左右両側にフィン部４２ａ，４２ｂ，４２ｃが一体成形された細径伝熱管ユニット４，４・・・を構成している。 And the small-diameter heat transfer tube units 4, 4... Provided with the heat transfer fins 42 have heat transfer tubes 41 (tube portions 41 a, 41 b), respectively, for example, as shown in FIGS. ) Thin and flat heat transfer fin plates (bonding members) (a) and (b) having a symmetric structure having a semi-circular groove having a semicircular cross section for formation are made to face each other, for example, as shown in FIG. In the state, by joining and integrating, the small-diameter heat transfer tube unit 4 in which the 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. , 4...

このように構成された細径伝熱管ユニット４，４・・・が、例えば図１２に示すように、、外部流体Ｆの流れ方向と平行に多数枚配列され、同配列状態において、各細径伝熱管ユニット４，４・・・上部のヘッダ２Ａ，２Ｂへの接続用開口端部４１ｃ，４１ｄに入口ヘッダ２Ａ、出口ヘッダ２Ｂが接続されて、図９のような細径多管式熱交換器１が形成される。 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. Heat transfer tube units 4, 4... An inlet header 2A and an outlet header 2B are connected to the opening end portions 41c and 41d for connection to the headers 2A and 2B at the upper portion, and a small diameter multitubular heat exchange as shown in FIG. A vessel 1 is formed.

以上のような構成によれば、本来伝熱率の高い多数本の細径の伝熱管４１の管体部４１ａ，４１ｂの両側に、さらに伝熱面積拡大用の伝熱フィン４２（フィン部４２ａ，４２ｂ，４２ｃ）が付加されることから、多数本の細径伝熱管４１，４１・・・の管体部４１ａ，４１ｂ、４１ａ，４１ｂ・・・による熱伝達率の良さに加えて、伝熱面積も大きく増大して、全体としての熱交換性能が大きく向上し、空気調和機用の熱交換器としての使用条件にも適したものとなる。 According to the above configuration, the heat transfer fins 42 (fin portions 42a) for further expanding the heat transfer area are provided on both sides of the tube portions 41a and 41b of the large number of small-diameter heat transfer tubes 41 with originally high heat transfer rates. , 42b, 42c), in addition to the good heat transfer coefficient by the tube portions 41a, 41b, 41a, 41b ... of the multiple small-diameter heat transfer tubes 41, 41 ... The heat area is also greatly increased, the heat exchange performance as a whole is greatly improved, and it is suitable for use conditions as a heat exchanger for an air conditioner.

また、以上の構成の場合、上記図１２のように細径伝熱管ユニット４，４・・・を並設して熱交部３を構成すると、伝熱管４１，４１・・・の管体部４１ａ，４１ｂ、４１ａ，４１ｂ・・・同士が相互に近接するので、通風抵抗が増大し、フィンピッチに限界が生じる。そこで、このような問題を解決するために、例えば図１３に示すように、外部流体Ｆの流れる前後方向に交互に位置を変え、全体として千鳥構造に配設することも可能である。 Further, in the case of the above configuration, when the heat exchanger 3 is configured by arranging the small-diameter heat transfer tube units 4, 4... As shown in FIG. 12, the tube portions of the heat transfer tubes 41, 41. Since 41a, 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. 13, 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.

このような構成によると、流れの方向と平行に隣合う細径伝熱管ユニット４，４の管体部４１ａ，４１ｂ、４１ａ，４１ｂ・・・同士が外部流体Ｆの流れ方向に所定寸法偏位し、それら相互の間隔も広くなるので、外部流体Ｆの流路抵抗が小さくなり、また各管体部４１ａ，４１ｂ、４１ａ，４１ｂ・・・および伝熱フィン４２（フィン部４２ａ，４２ｂ，４２ｃ）、４２（４２ａ，４２ｂ，４２ｃ）の表面を均一かつスムーズに流れるようになる。したがって、さらに熱交換性能が向上する。 According to such a configuration, the tube portions 41a, 41b, 41a, 41b,... Of the small-diameter heat transfer tube units 4 and 4 adjacent in parallel to the flow direction are deviated by a predetermined dimension in the flow direction of the external fluid F. In addition, since the distance between them becomes wider, the flow resistance of the external fluid F becomes smaller, and the tube portions 41a, 41b, 41a, 41b... And the heat transfer fins 42 (fin portions 42a, 42b, 42c). ), 42 (42a, 42b, 42c). Therefore, the heat exchange performance is further improved.

なお、以上のような細径伝熱管ユニット４は、例えば図１４に示すように、管体部４１ａ，４１ｂと該管体部４１ａ，４１ｂの両側に設けられたＵ状のカシメ部４１ｅ，４１ｆ、４１ｅ，４１ｆにカシメ固定された１枚板構造の伝熱フィンプレート４２ａ，４２ｂ，４２ｃによっても、全く同様に形成することができる。 Note that the small-diameter heat transfer tube unit 4 as described above includes, for example, as shown in FIG. 14, tube portions 41a and 41b and U-shaped crimp portions 41e and 41f provided on both sides of the tube portions 41a and 41b. , 41e and 41f can be formed in exactly the same manner by heat transfer fin plates 42a, 42b and 42c having a single plate structure fixed by caulking.

特開２００１−１１６４８１号公報（明細書第１−３頁、図１−４）Japanese Patent Laid-Open No. 2001-116481 (Specification, page 1-3, FIG. 1-4)

ところで、以上のような構成の場合、千鳥配列構造を採用すると、外部流体Ｆの流れの方向と平行に隣合う伝熱管４１，４１・・・の管体部４１ａ，４１ｂ、４１ａ，４１ｂ同士が外部流体Ｆの流れ方向（上流側又は下流側）に所定寸法偏位し、それら相互の間隔も広くなるので、外部流体Ｆの流路抵抗が小さくなり、また各管体部４１ａ，４１ｂ、４１ａ，４１ｂ・・・およびフィン部４２ａ，４２ｂ，４２ｃ、４２ａ，４２ｂ，４２ｃ・・・の表面を均一かつスムーズに効率良く流れ、熱交換性能が向上する。 By the way, in the case of the above structure, when the staggered arrangement structure is adopted, the tube portions 41a, 41b, 41a, 41b of the heat transfer tubes 41, 41,. A predetermined dimension is deviated in the flow direction (upstream side or downstream side) of the external fluid F, and the distance between them is widened. Therefore, the flow resistance of the external fluid F is reduced, and each of the tube portions 41a, 41b, 41a. , 41b... And fin portions 42a, 42b, 42c, 42a, 42b, 42c... Uniformly and smoothly and efficiently, and heat exchange performance is improved.

しかし、そのようにすると、各伝熱フィン４２，４２・・・の端部が交互に凹凸状態を呈し、端部が不揃いになるとともに、全体としての幅が大きくなる。それにも拘わらず、各伝熱フィン４２，４２・・・の伝熱面積は同じであり、その大きくなった熱交幅分だけには拡大されない。 However, if it does so, the edge part of each heat-transfer fin 42,42 ... will exhibit an uneven | corrugated state alternately, and an edge part becomes uneven and the width | variety as a whole becomes large. Nevertheless, the heat transfer areas of the heat transfer fins 42, 42,... Are the same, and are not enlarged only by the increased heat exchange width.

また、伝熱フィン４２，４２・・・上流側および下流側各端面部のフィン枚数が１／２になるので、同端面部の強度が、千鳥配列でない場合の略半分に低下する。 Further, since the number of fins on each of the heat transfer fins 42, 42... Upstream and downstream end face portions is halved, the strength of the end face portions is reduced to substantially half that in the case of not having a staggered arrangement.

本願発明は、このような事情に基いてなされたもので、上述の細径伝熱管ユニットの管体部両側の伝熱フィンの外部流体の上流側と下流側各端面を、管体部を千鳥配列構造としながら、同一端面状態に揃えることによって、上述の問題を解決した細径多管式熱交換器の細径伝熱管ユニットを提供することを目的とするものである。 The present invention has been made based on such circumstances. The upstream and downstream end faces of the external fluid of the heat transfer fins on both sides of the tube portion of the small-diameter heat transfer tube unit described above, and the tube portions are staggered. An object of the present invention is to provide a small-diameter heat transfer tube unit of a small-diameter multi-tube heat exchanger that solves the above-mentioned problems by arranging them in the same end face state while having an arrangement structure.

本願発明は、該目的を達成するために、次のような課題解決手段を備えて構成されている。 In order to achieve the object, the present invention includes the following problem solving means.

（１）第１の課題解決手段
本願発明の第１の課題解決手段は、内部流体と外部流体Ｆとの間で熱交換を行わせる前後２列の細径の管体部４１ａ，４１ｂと該管体部４１ａ，４１ｂの両側に設けられた伝熱フィン４２ａ，４２ｂ，４２ｃよりなる細径伝熱管ユニット４を、外部流体Ｆの流れる方向と平行に所定の間隔を保って複数枚並設してなる細径多管式熱交換器の細径伝熱管ユニットであって、上記管体部４１ａ，４１ｂを千鳥構造に配列し、かつ該千鳥配列時において外部流体Ｆの上流側又は下流側に偏位する上記伝熱フィン４２ａ，４２ｂ，４２ｃの外部流体Ｆの下流側又は上流側のフィン幅を拡大することにより、それらの各端面を同一端面状態に揃えたことを特徴としている。 (1) First problem-solving means The first problem-solving means of the present invention includes two rows of small-diameter tubular body portions 41a, 41b that allow heat exchange between the internal fluid and the external fluid F, and the A plurality of small-diameter heat transfer tube units 4 including heat transfer fins 42a, 42b, 42c provided on both sides of the tube portions 41a, 41b are arranged in parallel with a predetermined interval in parallel with the direction in which the external fluid F flows. A small-diameter multi-tube heat exchanger with a small-diameter heat transfer tube unit, in which the tube portions 41a and 41b are arranged in a staggered structure, and at the upstream or downstream side of the external fluid F in the staggered arrangement. By expanding the fin width on the downstream side or the upstream side of the external fluid F of the heat transfer fins 42a, 42b, and 42c that are displaced, the respective end faces are aligned in the same end face state.

このような構成によると、伝熱管４１，４１・・・の管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・の千鳥配列構造により拡大された熱交換器１の幅に対応して、伝熱フィン４２，４２・・・全体のフィン幅も拡大され、同一容積下での有効伝熱面積が拡大され、その分熱交換性能が向上する。その結果、熱交換器１の実質的なコンパクト化が可能となる。 According to such a configuration, heat transfer is performed corresponding to the width of the heat exchanger 1 expanded by the staggered arrangement structure of the tube portions 41a, 41b, 41b, 41a. The overall fin width of the fins 42, 42... Is expanded, the effective heat transfer area under the same volume is expanded, and the heat exchange performance is improved accordingly. As a result, the heat exchanger 1 can be substantially made compact.

また、伝熱フィン４２，４２・・・の上流側および下流側各端面部のフィン枚数が２倍になるので、同端面部の強度も、略２倍に向上し、変形しにくくなる。 Further, since the number of fins at the upstream and downstream end face portions of the heat transfer fins 42, 42... Is doubled, the strength of the end face portions is also almost doubled and is not easily deformed.

その結果、熱交換器１全体のフィンピッチも揃えやすいく、その組付性も良くなる。 As a result, the fin pitch of the entire heat exchanger 1 can be easily aligned, and the assembling property is improved.

（２）第２の課題解決手段
本願発明の第２の課題解決手段は、上記第１の課題解決手段の構成において、前後２列の細径の管体部４１ａ，４１ｂの何れか一方側の管体部４１ｂ又は４１ａの外周側に位置する伝熱フィン４２ｃ又は４２ａのフィン幅Ｗ₁を、他方側の管体部４１ａ又は４１ｂの外周側に位置する伝熱フィン４２ａ又は４２ｃのフィン幅Ｗ₂よりも大きく形成したこと特徴としている。 (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, either one of the front and rear two rows of small-diameter tube portions 41a and 41b is provided. the fin width W ₁ of the tube part 41b or the heat transfer fins 42c or 42a located on the outer peripheral side of the 41a, the fin width W of the heat transfer fins 42a or 42c is positioned on the outer peripheral side of the other side of the tube portion 41a or 41b It is characterized by being formed larger than ₂ .

このような構成によると、伝熱管４１，４１・・・の管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・の千鳥配列構造により拡大された熱交換器１の幅に対応して、伝熱フィン４２，４２・・・全体のフィン幅も拡大され、同一容積下での有効伝熱面積が拡大され、その分熱交換性能が向上する。その結果、実質的な熱交換器１のコンパクト化が可能となる。 According to such a configuration, heat transfer is performed corresponding to the width of the heat exchanger 1 expanded by the staggered arrangement structure of the tube portions 41a, 41b, 41b, 41a. The overall fin width of the fins 42, 42... Is expanded, the effective heat transfer area under the same volume is expanded, and the heat exchange performance is improved accordingly. As a result, the heat exchanger 1 can be substantially made compact.

さらに、このような構成によると、伝熱管４１，４１・・・の管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・のレイアウトの自由度が向上し、各伝熱管４１，４１・・・の管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・を千鳥構造に配列した時にも、それら各管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・のヘッダ部２Ａ，２Ｂとの接続口位置を異ならせることなく、コンパクトに並設することができる。 Furthermore, according to such a structure, the freedom degree of the layout of the tube part 41a, 41b, 41b, 41a ... of the heat exchanger tubes 41, 41 ... improves, and each heat exchanger tube 41, 41 ... When the tubular body portions 41a, 41b, 41b, 41a,... Are arranged in a staggered structure, the connection port positions of the tubular body portions 41a, 41b, 41b, 41a,. It is possible to arrange them compactly without making them.

（３）第３の課題解決手段
本願発明の第３の課題解決手段は、上記第１又は第２の課題解決手段の構成において、管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・の位置を、全体的に伝熱フィン４２ａ，４２ｂ，４２ｃ、４２ｃ，４２ｂ，４２ａ・・・の後縁側へ偏位させることにより、伝熱フィン４２ａ，４２ｂ，４２ｃ、４２ａ，４２ｂ，４２ｃ前縁部の幅を大きくし、外部流体Ｆ流入部のフィン効率を低下させることによって、着霜を遅延させるようにしたことを特徴としている。 (3) Third Problem Solving Means The third problem solving means of the present invention is the configuration of the first or second problem solving means in which the positions of the tube portions 41a, 41b, 41b, 41a,. The width of the front edge of the heat transfer fins 42a, 42b, 42c, 42a, 42b, 42c by shifting the heat transfer fins 42a, 42b, 42c, 42c, 42b, 42a. Is increased, and the frost formation is delayed by reducing the fin efficiency of the inflow portion of the external fluid F.

このような構成によると、例えば空気調和機の室外機用の熱交換器として最適なものとなる。 According to such a structure, it becomes an optimal thing as a heat exchanger for the outdoor unit of an air conditioner, for example.

空気調和機用室外機の熱交換器の場合、伝熱フィン４２，４２・・・の前縁側では着霜を生じやすく、着霜量が増大すると、フィン前縁面と空気との直接の接触機会がなくなるとともに、伝熱フィン４２ａ，４２ｂ，４２ｃ、４２ｃ，４２ｂ，４２ａ・・・間の圧損が増大して、通風量が低下し、大幅な熱交換性能の低下を招く。 In the case of a heat exchanger for an outdoor unit for an air conditioner, frost formation is likely to occur on the front edge side of the heat transfer fins 42, 42... As the opportunity disappears, the pressure loss between the heat transfer fins 42a, 42b, 42c, 42c, 42b, 42a... Increases, the air flow rate decreases, and the heat exchange performance significantly decreases.

ところが、上述のように、伝熱管４１，４１・・・の管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・を外部流体Ｆの下流側である伝熱フィン４２ａ，４２ｂ，４２ｃ、４２ｃ，４２ｂ，４２ａ・・・の後縁側に偏位させると、その分前縁部分での内部流体との温度差が小さくなり、フィン効率が低下して着霜進度が低下し、デフロスト周期を長期化させることができる。 However, as described above, the heat transfer fins 42a, 42b, 42c, 42c, 42b, which are downstream of the external fluid F, are connected to the tube portions 41a, 41b, 41b, 41a,. , 42a..., 42a..., 42a..., 42a..., 42a. be able to.

その結果、さらなる熱交換性能の向上につながる。 As a result, the heat exchange performance is further improved.

（４）第４の課題解決手段
本願発明の第４の課題解決手段は、上記第１，第２又は第３の課題解決手段の構成において、管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・の位置を、伝熱フィン４２ａ，４２ｂ，４２ｃ、４２ｃ，４２ｂ，４２ａ・・・の前縁側へ偏位させることにより、伝熱フィン４２ａ，４２ｂ，４２ｃ、４２ｃ，４２ｂ，４２ａ・・・後縁部の幅を大きくし、外部流体Ｆ流出部の流れを整流することによって、凝縮水が飛散しないようにしたことを特徴としている。 (4) Fourth Problem Solving Means The fourth problem solving means of the present invention is the tube part 41a, 41b, 41b, 41a,... In the configuration of the first, second or third problem solving means. Is shifted to the front edge side of the heat transfer fins 42a, 42b, 42c, 42c, 42b, 42a, etc., so that the heat transfer fins 42a, 42b, 42c, 42c, 42b, 42a,. It is characterized in that the condensed water is prevented from scattering by enlarging the width of the portion and rectifying the flow of the outflow portion of the external fluid F.

このような構成によると、例えば空気調和機の室内機用の熱交換器として採用した時に、最適なものとなる。 According to such a configuration, for example, when it is adopted as a heat exchanger for an indoor unit of an air conditioner, it is optimum.

空気調和機用室内機の熱交換器の場合、伝熱フィン４２ａ，４２ｂ，４２ｃ、４２ｃ，４２ｂ，４２ａ・・・の後縁側では凝縮水の飛散を生じやすい問題がある。 In the case of a heat exchanger for an air conditioner indoor unit, there is a problem that condensate is likely to be scattered on the rear edge side of the heat transfer fins 42a, 42b, 42c, 42c, 42b, 42a,.

ところが、伝熱管４１，４１・・・の管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・を外部流体Ｆの上流側である伝熱フィン４２ａ，４２ｂ，４２ｃ、４２ｃ，４２ｂ，４２ａ・・・の前縁側に偏位させると、その分後縁部分の長さが長くなり、後縁側の空気の流れがスムーズに整流される。その結果、凝縮水の飛散が防止される。 However, the heat transfer fins 42 a, 42 b, 42 c, 42 c, 42 b, 42 a... That are upstream of the external fluid F are connected to the tube portions 41 a, 41 b, 41 b, 41 a. If it is displaced to the front edge side, the length of the rear edge portion is increased correspondingly, and the air flow on the rear edge side is smoothly rectified. As a result, scattering of condensed water is prevented.

（５）第５の課題解決手段
本願発明の第５の課題解決手段は、上記第１，第２，第３又は第４の課題解決手段の構成において、熱交換器が空気調和機等冷凍装置用のもので、内部流体が、Ｒ３２を５０ｗｔ％以上含む混合冷媒、又はＲ３２の単一冷媒、もしくはＣＯ₂冷媒等の高圧冷媒であることを特徴としている。 (5) Fifth Problem Solving Means The fifth problem solving means of the present invention is the configuration of the first, second, third or fourth problem solving means, wherein the heat exchanger is a refrigeration apparatus such as an air conditioner. 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.

上記第１，第２，第３又は第４の課題解決手段の構成によれば、内部流体と外部流体Ｆとの間で熱交換を行わせる細径の管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・と該管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・の両側に設けられた伝熱フィン４２ａ，４２ｂ，４２ｃ、４２ｃ，４２ｂ，４２ａ・・・よりなる複数の細径伝熱管ユニット４，４・・・を、外部流体Ｆの流れる方向と平行に所定の間隔を保って並設してなる細径多管式熱交換器の細径伝熱管ユニット４，４・・・において、管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・と伝熱フィン４２ａ，４２ｂ，４２ｃ、４２ｃ，４２ｂ，４２ａ・・・が隣接する通路部分の通路抵抗を小さくすることができ、伝熱性能、伝熱効率を向上させることができる。 According to the configuration of the first, second, third, or fourth problem solving means, the small-diameter tube portions 41a, 41b, 41b, 41a that allow heat exchange between the internal fluid and the external fluid F are performed. ... and a plurality of small-diameter heat transfer tube units composed of heat transfer fins 42a, 42b, 42c, 42c, 42b, 42a ... provided on both sides of the tube portions 41a, 41b, 41b, 41a ... Are arranged in parallel with the flow direction of the external fluid F at a predetermined interval in a small diameter heat transfer tube unit 4, 4. The pipe sections 41a, 41b, 41b, 41a ... and the heat transfer fins 42a, 42b, 42c, 42c, 42b, 42a ... can reduce the passage resistance of the adjacent passage portions, and the heat transfer performance, Heat transfer efficiency can be improved.

そのため、熱交換器が空気調和機等冷凍装置用のもので、内部流体がＲ３２を５０ｗｔ％以上含む混合冷媒、又はＲ３２の単一冷媒、もしくはＣＯ₂冷媒等の高圧冷媒である高効率の細径多管式熱交換器の細径伝熱管ユニットにも適したものとなる。 Therefore, the heat exchanger is for a refrigerating 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 multi-tube heat exchanger.

以上の結果、本願発明の細径多管式熱交換器の細径伝熱管ユニットによると、次のような有益な効果を得ることができる。 As a result, according to the small-diameter heat transfer tube unit of the small-diameter multi-tube heat exchanger of the present invention, the following beneficial effects can be obtained.

（１）管体部の千鳥配列により熱交部の通路抵抗を小さくできるとともに、伝熱フィン自体の伝熱面積が拡大する。その結果、熱交換性能が大きく向上する。また、伝熱フィンの端面部が揃えられるので、見映えも良くなる。 (1) The staggered arrangement of the tube sections can reduce the passage resistance of the heat exchange section, and the heat transfer area of the heat transfer fin itself can be expanded. As a result, the heat exchange performance is greatly improved. Further, since the end face portions of the heat transfer fins are aligned, the appearance is improved.

（２）また、その結果、伝熱フィン端面部の強度が向上するので、その変形が防止され、常に適正な通路面積が確保される。その結果、有効な通風量が維持されるので、熱交換性能が向上する。 (2) Further, as a result, the strength of the heat transfer fin end surface portion is improved, so that the deformation is prevented and an appropriate passage area is always secured. As a result, since an effective air flow rate is maintained, the heat exchange performance is improved.

また、組付性も向上する。 Also, the assembling property is improved.

（３）さらに、フィン幅を拡大した分だけ熱交換器トータルとしての熱交換性能が向上し、従来と同一の性能を得るとすれば、実質的な熱交換器のコンパクト化が可能となる。 (3) Furthermore, if the fin width is increased, the heat exchange performance as the total heat exchanger is improved, and if the same performance as the conventional one is obtained, the heat exchanger can be substantially downsized.

（４）それらの結果、高圧冷媒対応の空気調和機用冷凍装置用熱交換器の熱交換性能の向上をも有効に図ることができる。 (4) As a result, it is possible to effectively improve the heat exchange performance of the heat exchanger for a refrigerating apparatus for an air conditioner that supports high-pressure refrigerant.

（最良の実施の形態１）
先ず図１〜図４は、本願発明を実施するに際しての最良の実施の形態１に係る細径多管式熱交換器の細径伝熱管ユニットの構造を示している。 (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.

また図５および図６は、同構造の細径伝熱管ユニットを採用して構成した細径多管式熱交換器の構成を示している。 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.

すなわち、先ず図５に示す細径多管式熱交換器１は、相互に所定の間隔を保って並設された冷媒分配機能を有する入口ヘッダ２Ａおよび出口ヘッダ２Ｂと、該入口ヘッダ２Ａと出口ヘッダ２Ｂの各々に接続され、その下部側に位置して長手方向に沿って多数本並設された細径伝熱管ユニット（フィン付細径伝熱管）４，４・・・よりなる熱交部３とから構成されている。 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 and arranged on the lower side along the longitudinal direction. 3.

上記細径伝熱管ユニット４，４・・・は、例えば図１及び図２に示すように、その伝熱管（細径管）４１が全体としてＵ状に曲成され、その上端側各開口端部４１ｃ，４１ｄが上記入口ヘッダ２Ａ、出口ヘッダ２Ｂの底部側各開口部に各々接続されるようになっている一方、同Ｕ状の伝熱管４１の左右のストレートな管体部４１ａ，４１ｂには、それぞれその左右両側に位置して各々所定の幅のフィン部４２ａ，４２ｂ，４２ｃが設けられている（フィン部４２ｂは、管体部４１ａ，４１ｂに共通）。これらストレートな２本の管体部４１ａ，４１ｂ両側のフィン部４２ａ，４２ｂ，４２ｃは相互に連続して、上記Ｕ状の伝熱管４１に対する１枚の伝熱フィン４２を形成している。 As shown in FIGS. 1 and 2, for example, the small-diameter heat transfer tube units 4, 4,... The portions 41c and 41d are connected to the openings on the bottom side of the inlet header 2A and the outlet header 2B, respectively, while the left and right straight tube portions 41a and 41b of the U-shaped heat transfer tube 41 are connected to each other. Are respectively provided with fin portions 42a, 42b, 42c having predetermined widths located on both left and right sides (the fin portion 42b is common to the tube portions 41a, 41b). The fin portions 42a, 42b, 42c on both sides of the two straight tube body portions 41a, 41b are continuous with each other to form one heat transfer fin 42 for the U-shaped heat transfer tube 41.

そして、該伝熱管４１（管体部４１ａ，４１ｂ）および伝熱フィン４２（フィン部４２ａ，４２ｂ，４２ｃ）を備えた細径伝熱管ユニット４，４・・・は、例えば図４の（ａ），（ｂ）に示すように、それぞれ伝熱管４１（管体部４１ａ，４１ｂ）形成用の断面半円形状の凹溝部を中央部に有する貼り合わせ面が左右対称構造の薄くて扁平な縦長長方形状のフィンプレート（貼り合わせ部材）４Ａ，４Ｂを、例えば図１〜図３に示すように、相互に対向させた状態で接合一体化することにより形成され、それによって上記伝熱管４１のストレートな管体部４１ａ，４１ｂの左右両側にフィン部４２ａ，４２ｂ，４２ｃが一体形成された同細径伝熱管ユニット４，４・・・を構成している（フィン部４２ｂは管体部４１ａ，４１ｂに共通）。 The small-diameter heat transfer tube units 4, 4... Having the heat transfer tubes 41 (tube portions 41a, 41b) and the heat transfer fins 42 (fin portions 42a, 42b, 42c) are, for example, shown in FIG. ), (B), a thin and flat vertically long laminar structure with a laminating surface with a semi-circular groove having a semicircular cross section for forming the heat transfer tubes 41 (tube portions 41a, 41b), respectively. For example, as shown in FIGS. 1 to 3, the rectangular fin plates (bonding members) 4 A and 4 B are joined and integrated in a state of being opposed to each other. The same thin-diameter heat transfer tube units 4, 4... Are formed by integrally forming fin portions 42 a, 42 b, 42 c on the left and right sides of each of the tube portions 41 a, 41 b (the fin portion 42 b is a tube portion 41 a, 41b).

このように構成された細径伝熱管ユニット４，４・・・は、例えば図６に示すように、、外部流体Ｆの流れ方向と平行に所定のピッチで多数枚並設して配列され、同配列状態において、各細径伝熱管ユニット４，４・・・上部のヘッダへの接続用開口端部４１ｃ，４１ｄ、４１ｄ，４１ｃ・・・に入口ヘッダ２Ａ、出口ヘッダ２Ｂが接続されて、最終的に図５のような細径多管式熱交換器１が形成される。上記細径伝熱管ユニット４，４・・・上部のヘッダ部２Ａ，２Ｂへの接続用開口端部４１ｃ，４１ｄ、４１ｄ，４１ｃは、それぞれ伝熱フィン４２，４２・・・上部の左右両側にヘッダ部２Ａ，２Ｂへの嵌合用の凸部４４ａ，４４ｂ、４４ｂ，４４ａ・・・を設け、同部分に形成されている。 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. The small-diameter heat transfer tube units 4, 4... Open end portions 41 c, 41 d, 41 d, 41 c for connection to the upper header portions 2 A, 2 B are respectively provided on the left and right sides of the heat transfer fins 42, 42. Protrusions 44a, 44b, 44b, 44a... For fitting to the header parts 2A, 2B are provided and formed in the same part.

このような構成によれば、本来伝熱率の高い細径の伝熱管４１，４１・・・の管体部４１ａ，４１ｂ、４１ａ，４１ｂ・・・の両側に、さらに伝熱面積拡大用の伝熱フィン４２（フィン部４２ａ，４２ｂ，４２ｃ）が付加されることから、細径伝熱管４１の管体部４１ａ，４１ｂによる熱伝達率の良さに加えて、伝熱面積も大きく増大して、全体としての熱交換性能が大きく向上し、空気調和機用の熱交換器としての使用条件にも適したものとなる。 According to such a configuration, the heat transfer area is further expanded on both sides of the tube portions 41a, 41b, 41a, 41b... Of the small heat transfer tubes 41, 41. Since the heat transfer fins 42 (fin portions 42a, 42b, 42c) are added, in addition to the good heat transfer rate by the tube portions 41a, 41b of the small-diameter heat transfer tubes 41, the heat transfer area is also greatly increased. As a result, the heat exchange performance as a whole is greatly improved, and it is suitable for use conditions as a heat exchanger for an air conditioner.

ところで、このような構成の場合、上記図５のように多数枚の細径伝熱管ユニット４，４・・・を並設して熱交部３を構成するに際し、そのまま各ユニット４，４・・・を同じ状態で各々並設したのでは、前述の図１４の場合と同様に隣合う伝熱管４１の管体部４１ａ，４１ｂ、４１ａ，４１ｂ・・・同士が相互に近接して、通風抵抗が増大するので、フィンピッチにも限界が生じる。他方、この問題を解決するために、例えば前述の図１５に示すように、外部流体Ｆの流れる前後方向に交互に位置を変え、全体として千鳥構造に配列したのでは、各伝熱フィン４２，４２・・・の端部が交互に凹凸状態を呈し、端部が不揃いになるとともに、全体としての幅（上下流方向の幅）が大きくなる。したがって、その分熱交部３の寸法が大きくなり、コンパクト性に欠ける。それにも拘わらず、各伝熱フィン４２，４２・・・の伝熱面積は、同一であり、その大きくなった熱交幅分だけには拡大されない。 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 FIG. .. are arranged side by side in the same state, the tube portions 41a, 41b, 41a, 41b,... Of adjacent heat transfer tubes 41 are close to each other in the same manner as in the case of FIG. As the resistance increases, the fin pitch is also limited. On the other hand, in order to solve this problem, for example, as shown in FIG. 15 described above, the heat transfer fins 42, The ends of 42... Are alternately uneven, the ends are uneven, and the overall width (the width in the upstream / downstream direction) is increased. Therefore, the dimension of the heat exchange part 3 becomes large correspondingly and lacks compactness. Nevertheless, the heat transfer areas of the heat transfer fins 42, 42,... Are the same, and are not enlarged only by the increased heat exchange width.

また、伝熱フィン４２，４２・・・端面部のフィン枚数が１／２になり、同端面部の強度が、千鳥配列でない場合の略半分に低下する。さらに、上記ヘッダ２Ａ，２Ｂとの接続用開口端部４１ｃ，４１ｄ、４１ｄ，４１ｃ・・・の位置が合わなくなる。 Further, the number of fins on the heat transfer fins 42, 42... End face part is halved, and the strength of the end face part is reduced to substantially half that in the case where the staggered arrangement is not used. Further, the positions of the opening end portions 41c, 41d, 41d, 41c,... For connection with the headers 2A, 2B are not aligned.

そこで、この実施の形態では、例えば図１〜図４に示すように、先ず上記Ｕ状の伝熱管４１の２本のストレートな管体部４１ａ，４１ｂの内の一方側ストレートな管体部４１ｂ（又は４１ａ）の外周側フィン部４２ｃ（又は４２ａ）のフィン幅Ｗ₁（又はＷ₂）を、他方側管体部４１ａ（又は４１ｂ）の外周側フィン部４２ａ（又は４２ｃ）のフィン幅Ｗ₂（又はＷ₁）の２倍となるように寸法ａ分だけ拡大し、伝熱フィン４２の伝熱面積を大きくしている。 Therefore, in this embodiment, for example, as shown in FIGS. 1 to 4, first, one straight tube body portion 41 b of the two straight tube body portions 41 a and 41 b of the U-shaped heat transfer tube 41. The fin width W ₁ (or W ₂ ) of the outer peripheral fin portion 42c (or 42a) of (or 41a) is changed to the fin width W of the outer fin portion 42a (or 42c) of the other tubular portion 41a (or 41b). ₂ (or W ₁ ) is enlarged by a dimension a so as to be twice that of W _1, and the heat transfer area of the heat transfer fins 42 is increased.

そして、その上で上述した細径伝熱管ユニット４上部のヘッダへの接続用開口端部４１ｄ（又は４１ｃ）を有する嵌合用凸部４４ｂ（又は４４ａ）を同フィン幅Ｗ₁（又はＷ₂）の拡大寸法ａ分だけ外周側に偏位させて設ける一方、それに対応して、上記一方側管体部４１ｂ（又は４１ａ）を、従来のように、その上端側開口端部４１ｄ（又は４１ｃ）から真っ直ぐ下方に直線的に延設するのではなく、同寸法ａだけ拡大されたフィン部４２ｃ（又は４２ａ）の管体部４１ｂ（又は４１ａ）側に一旦寸法ａ分だけクランク状に曲成した上で下方に延設することにより、つまりクランク状の曲成部Ｒを形成することにより、結果としてＵ状の伝熱管４１の管体部４１ａ，４１ｂが全体として伝熱フィン４２の左右何れか一方側に偏位した形で設けられるように構成している。 The connection opening end 41d of the upper to the header of the thin heat transfer tube units 4 top above (or 41c) fitting protrusion 44b having (or 44a) of the same fin width W ₁ (or W ₂₎ In contrast, the one-side tube portion 41b (or 41a) is provided at its upper end side opening end portion 41d (or 41c) as in the prior art. Instead of linearly extending straight downward from the pipe portion 41b (or 41a) side of the fin portion 42c (or 42a) enlarged by the same dimension a, the portion once bent in a crank shape by the dimension a. By extending downward, that is, by forming a crank-shaped bent portion R, the tube portions 41a and 41b of the U-shaped heat transfer tube 41 as a result are either left or right of the heat transfer fins 42 as a whole. Installed in a deviated form on one side It is configured to be.

そして、この状態で、さらに上記伝熱フィン４２における伝熱管４１の２本のストレートな管体部４１ａと４１ｂの間の管体部４１ａ，４１ｂに共通なフィン部４２ｂおよびクランク状に曲成された管体部４１ｃの外周側フィン部４２ｃの中央には、それぞれ伝熱フィン４２の並設方向両面側に貫通する開口として、上記管体部４１ａ，４１ｂの外径と同程度の幅の２本の上下方向に長いスリット４３ａ，４３ｂが設けられている。 In this state, the fin portion 42b and the crank portion 41b that are common to the tube portions 41a and 41b between the two straight tube portions 41a and 41b of the heat transfer tube 41 in the heat transfer fin 42 are further bent. In the center of the outer peripheral side fin part 42c of the tubular body part 41c, an opening penetrating the both sides of the heat transfer fins 42 in the juxtaposed direction is provided with a width of about 2 as the outer diameter of the tubular body parts 41a and 41b. Long slits 43a and 43b are provided in the vertical direction of the book.

これら２本のスリット４３ａ，４３ｂの内、スリット４３ａは、上記のように伝熱フィン４２中央部の管体部４１ａと４１ｂに共通なフィン部４２ｂの幅方向中央に、またスリット４３ｂは、上記のように管体部４１ｂ外周側のフィン部４２ｃの中央に、それぞれ設けられている。そして、それらスリット４３ａ，４３ｂにより、フィン部４２ａのフィン幅Ｗ₂の２倍のフィン幅Ｗ₃のフィン部４２ｂは、フィン幅Ｗ₃₁とＷ₃₂の２つの独立したフィン部４２ｂ₁，４２ｂ₂に、また上記フィン部４２ａのフィン幅Ｗ₂の２倍のフィン幅Ｗ₁のフィン部４２ｃは、フィン幅１／２Ｗ₁のフィン部と同じフィン幅１／２Ｗ₁のフィン部の２つのフィン部に分割されている。 Of these two slits 43a and 43b, the slit 43a is at the center in the width direction of the fin portion 42b common to the tube portions 41a and 41b at the center of the heat transfer fin 42 as described above, and the slit 43b is As described above, the fin portions 42c on the outer peripheral side of the tubular body portion 41b are respectively provided at the centers. And those slits 43a, the 43 b, 2 times the fin portions 42b of the fin width W ₃ of the fin width W ₂ of the fin portion 42a has two separate fin portion 42b of the fin width W ₃₁ and W ₃₂ _1, 42b ₂ to also twice the fin portion 42c of the fin width W ₁ of the fin width W ₂ of the fin portions 42a, the two fins of the fin portion of the same fin width and fin of the fin width _₁ / 2W 1 1 / 2W 1 It is divided into parts.

ただし、この場合、後者のフィン部４２ｃは、少なくとも管体部４１ｂに対して１つのフィンとしてしか機能しないので、これについては、あくまでもフィン幅Ｗ₁の１枚のフィンとして考える。 However, in this case, the latter fin portion 42c, since only work as one fin to at least the tube part 41b, for this, merely considered as a single fin of the fin width W _1.

しかも、そのように構成された各細径伝熱管ユニット４，４・・・は、例えば図４，図６に示すように、その左右方向を交互に逆にして並設（４１ａ，４１ｂ，４１ｂ，４１ａ、４１ａ，４１ｂ，４１ｂ，４１ａ・・・）することにより、上記細径伝熱管ユニット４，４・・・の伝熱管４１，４１・・・のストレートな管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・が全体として千鳥状の配置となるように、外部流体Ｆの流れ方向に対して平行に配列されている。 Moreover, each of the small-diameter heat transfer tube units 4, 4... Configured as described above is arranged in parallel (41 a, 41 b, 41 b) with their left and right directions alternately reversed, as shown in FIGS. , 41a, 41a, 41b, 41b, 41a ...), the straight tube portions 41a, 41b, 41b of the heat transfer tubes 41, 41 ... of the small-diameter heat transfer tube units 4, 4 ... , 41a,... Are arranged in parallel with the flow direction of the external fluid F so that they are arranged in a staggered pattern as a whole.

この結果、細径伝熱管ユニット４，４・・・の各々を空気流前後方向に位置をずらすまでもなく、外部流体Ｆの流れの方向と平行に隣合う細径伝熱管ユニット４，４の管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・自体が外部流体Ｆの流れ方向の上流と下流に所定寸法ａずつ偏位し、それら相互の間隔も広くなるので、外部流体Ｆの流路抵抗が小さくなり、また各管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・および伝熱フィン４２（４２ａ，４２ｂ，４２ｃ）、４２（４２ｃ，４２ｂ，４２ａ）・・・の表面を均一かつスムーズに流れるようになる。しかも、以上の構成では、管体部４１ａ，４１ｂの内の一方側管体部４１ｂの外周側フィン部４２ｃのフィン幅Ｗ₁を、他方側管体部４１ａの外周側フィン部４２ａのフィン幅Ｗ₂の２倍となるように、寸法ａ分だけ拡大し、各伝熱フィン４２，４２・・・の伝熱面積を拡大しているので、熱交部３全体の伝熱面積が増大して、熱交換性能が大きく向上する。 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 41a, 41b, 41b, 41a,... Themselves are displaced by a predetermined dimension a upstream and downstream in the flow direction of the external fluid F, and the distance between them is widened, the flow resistance of the external fluid F is increased. And the surfaces of the tube portions 41a, 41b, 41b, 41a... And the heat transfer fins 42 (42a, 42b, 42c), 42 (42c, 42b, 42a). It begins to flow. Moreover, in the above configuration, the tube part 41a, while the fin width W ₁ of the outer peripheral side fin portion 42c of the side tube body portion 41b, the fin width of the outer peripheral side fin portion 42a of the other side tube body portion 41a of the 41b to be twice the W _2, enlarged by the dimension a partial, since the larger heat transfer area of the heat transfer fins 42, 42 ..., the heat transfer area of the entire heat exchange unit 3 is increased Thus, the heat exchange performance is greatly improved.

また、同構成では、以上のようにガス抜きのためのスリット４３ａ，４３ｂが、伝熱フィン４２の幅の広いフィン部４２ｂ，４２ｃ部分の中央に位置して長手方向の略全体に亘って形成されているので、同伝熱フィン４２のフィン部４２ａ，４２ｂ，４２ｃの全体に亘って、それら各スリットが有効な前縁効果を果たすので、さらに熱交換性能が向上する。 Further, in the same configuration, as described above, the slits 43a and 43b for venting are located at the center of the wide fin portions 42b and 42c of the heat transfer fin 42 and are formed over substantially the entire longitudinal direction. Therefore, since each slit performs an effective leading edge effect over the entire fin portions 42a, 42b, and 42c of the heat transfer fin 42, the heat exchange performance is further improved.

しかも、同構成の場合、例えば図６から明らかなように、上記スリット４３ａ，４３ｂ、４３ｂ，４３ａ・・・が、ちょうど並設状態において隣合う細径伝熱管ユニット４，４・・・の各管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・と並設方向に対向する位置に来るように配設されている。 In addition, in the case of the same configuration, for example, as is apparent from FIG. 6, the slits 43 a, 43 b, 43 b, 43 a. It arrange | positions so that it may come to the position which opposes the pipe-body parts 41a, 41b, 41b, 41a ... in the arrangement direction.

したがって、各管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・部分で側方に曲がって流れる外部流体（縮流）の一部が、同スリット４３ａ，４３ｂ、４３ｂ，４３ａ・・・を介して隣側の通路にもバイパスして流れるようになり、より伝熱フィン４２，４２・・・間の流通抵抗が小さくなるとともに、より前縁効果が向上する。 Therefore, a part of the external fluid (constricted flow) that bends laterally at each tubular portion 41a, 41b, 41b, 41a,..., Passes through the slits 43a, 43b, 43b, 43a,. Bypassing the adjacent passage, the flow resistance between the heat transfer fins 42, 42... Is reduced, and the leading edge effect is further improved.

以上のような構成によると、先ず伝熱管４１，４１・・・の管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・の千鳥配列構造により拡大された熱交換器１の幅に対応して、伝熱フィン４２，４２・・・全体のフィン幅も拡大され、同一容積下での有効伝熱面積が拡大され、その分熱交換性能が向上する。その結果、実質的な熱交換器１のコンパクト化が可能となる。 According to the above configuration, first, in correspondence with the width of the heat exchanger 1 expanded by the staggered arrangement structure of the tube portions 41a, 41b, 41b, 41a ... of the heat transfer tubes 41, 41 ... The heat transfer fins 42, 42... Are expanded in overall fin width, the effective heat transfer area under the same volume is expanded, and the heat exchange performance is improved accordingly. As a result, the heat exchanger 1 can be substantially made compact.

また、以上の構成では、その場合において、例えば前後２列の細径伝熱管４１の管体部４１ａ，４１ｂの内の何れか一方側の管体部４１ｂ（又は４１ａ）の外周側に位置するフィン部４２ｃ（又は４２ａ）の幅Ｗ₁を、他方側の管体部４１ａ（又は４１ｂ）の外周側に位置するフィン部４２ａ（又は４２ｃ）の幅Ｗ₂よりも大きく形成することにより、同構成を実現している。 Moreover, in the above structure, in that case, for example, it is located on the outer peripheral side of the tube portion 41b (or 41a) on either one of the tube portions 41a and 41b of the two rows of the small diameter heat transfer tubes 41. By forming the width W ₁ of the fin part 42c (or 42a) larger than the width W _{2 of} the fin part 42a (or 42c) located on the outer peripheral side of the other tube part 41a (or 41b), The configuration is realized.

したがって、そのような構成によると、伝熱管４１，４１・・・の管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・レイアウトの自由度が向上し、各伝熱管４１，４１・・・の管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・を千鳥構造に配列した時にも、各伝熱管４１ａ，４１ｂ、４１ｂ，４１ａ・・・のヘッダ部２Ａ，２Ｂ、２Ｂ，２Ａとの接続口位置を異ならせることなく、コンパクトに並設することができる。 Therefore, according to such a configuration, the tube portions 41a, 41b, 41b, 41a... Of the heat transfer tubes 41, 41. When the body parts 41a, 41b, 41b, 41a,... Are arranged in a staggered structure, the positions of the connection ports with the header parts 2A, 2B, 2B, 2A of the heat transfer tubes 41a, 41b, 41b, 41a,. It can be arranged in parallel without making it different.

なお、以上の構成において、例えば図３のように、中央のスリット４３ａで分割されたフィン部４２ｂ₁，４２ｂ₂をも１つの独立したフィン部として考えた場合には、上記隣り合う伝熱フィン４２，４２・・・相互のフィン幅Ｗ₂：Ｗｂ₁：Ｗｂ₂：Ｗ₁とＷ₁：Ｗｂ₂：Ｗｂ₁：Ｗ₂の関係は、例えば図６に示すように、管体部が前後２列４１ａ，４１ｂ、４１ｂ，４１ａ・・・の場合で、１：１：１：２と２：１：１：１の関係に構成することが好ましい。 In the above configuration, when the fin portions 42b ₁ and 42b ₂ divided by the central slit 43a are also considered as one independent fin portion as shown in FIG. 3, for example, the adjacent heat transfer fins 42, 42 ... mutual fin widths W ₂ : Wb ₁ : Wb ₂ : W ₁ and W ₁ : Wb ₂ : Wb ₁ : W ₂ , for example, as shown in FIG. In the case of two rows 41a, 41b, 41b, 41a..., It is preferable to configure the relationship of 1: 1: 1: 2 and 2: 1: 1: 1.

さらに、以上の構成では、上記熱交換器１が空気調和機等冷凍装置用のもので、内部流体が、Ｒ３２を５０ｗｔ％以上含む混合冷媒、又はＲ３２の単一冷媒、もしくはＣＯ₂冷媒等の高圧冷媒である場合に適用される。 Further, in the above configuration, the heat exchanger 1 is for a refrigerating 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 CO ₂ refrigerant. It is applied when it is a high pressure refrigerant.

以上の構成によれば、内部流体と外部流体Ｆとの間で熱交換を行わせる細径伝熱管４１，４１・・・の管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・と該管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・の両側に設けられた伝熱フィン４２ａ，４２ｂ，４２ｃ、４２ｃ，４２ｂ，４２ａ・・・よりなる複数の細径伝熱管ユニット４，４・・・を、外部流体Ｆの流れる方向と平行に所定の間隔を保って並設してなる細径多管式熱交換器の細径伝熱管ユニット４，４・・・において、伝熱フィン４２，４２・・・の伝熱面積が広く、また管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・と伝熱フィン４２ａ，４２ｂ，４２ｃ、４２ｃ，４２ｂ，４２ａ・・・が隣接する通路部分の通路抵抗を小さくすることができ、伝熱性能、伝熱効率を極めて有効に向上させることができる。 According to the above configuration, the tube portions 41a, 41b, 41b, 41a,... Of the small-diameter heat transfer tubes 41, 41,. A plurality of small-diameter heat transfer tube units 4, 4... Composed of heat transfer fins 42a, 42b, 42c, 42c, 42b, 42a... Provided on both sides of the portions 41a, 41b, 41b, 41a. In the small diameter heat transfer tube units 4, 4... Of the small diameter multitubular heat exchanger arranged in parallel with a predetermined interval in parallel with the flow direction of the external fluid F, the heat transfer fins 42, 42. .. The heat transfer area is large, and the pipe portions 41a, 41b, 41b, 41a... And the heat transfer fins 42a, 42b, 42c, 42c, 42b, 42a. It can be made small, making the heat transfer performance and heat transfer efficiency extremely effective. It is possible to above.

そのため、熱交換器が空気調和機等冷凍装置用のもので、内部流体がＲ３２を５０ｗｔ％以上含む混合冷媒、又はＲ３２の単一冷媒、もしくはＣＯ₂冷媒等の高圧冷媒である高効率の細径多管式熱交換器の細径伝熱管ユニットに適したものとなる。 Therefore, the heat exchanger is for a refrigerating 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 multi-tube heat exchangers.

以上の結果、本実施の形態の細径多管式熱交換器の細径伝熱管ユニットによると、次のような有益な効果を得ることができる。 As a result, according to the small diameter heat transfer tube unit of the small diameter multi-tube heat exchanger of the present embodiment, the following beneficial effects can be obtained.

また、組付性も向上する。 Also, the assembling property is improved.

（最良の実施の形態２）
次に図７は、本願発明を実施するに際しての最良の実施の形態２に係る細径多管式熱交換器の細径伝熱管ユニットの構造を示している。 (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.

この実施の形態の構成では、上述の最良の実施の形態１に係る細径伝熱管ユニット４，４・・・よりなる細径多管式熱交換器１の構成において、細径伝熱管４１，４１・・・の管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・を空気流Ｆの下流側（伝熱フィン４２の後縁側）に偏位させ、空気調和機の室外機の熱交換器として最適なものとなるように構成したことを特徴とするものである。 In the configuration of this embodiment, in the configuration of the small-diameter multi-tube heat exchanger 1 including the small-diameter heat transfer tube units 4, 4... According to the above-described best embodiment 1, the small-diameter heat transfer tube 41, As a heat exchanger for the outdoor unit of the air conditioner, the pipe portions 41a, 41b, 41b, 41a, ... are displaced to the downstream side of the air flow F (the rear edge side of the heat transfer fins 42). It is characterized by being configured to be optimal.

空気調和機用室外機の熱交換器の場合、伝熱フィン４２，４２・・・の前縁側では着霜を生じやすく、着霜量が増大すると、フィン前縁面と空気との直接の接触機会がなくなるとともに、伝熱フィン４２，４２・・・間の圧損が増大して、通風量が低下し、大幅な熱交換性能の低下を招く。 In the case of a heat exchanger for an outdoor unit for an air conditioner, frost formation is likely to occur on the front edge side of the heat transfer fins 42, 42... As the opportunity disappears, the pressure loss between the heat transfer fins 42, 42... Increases, the air flow rate decreases, and the heat exchange performance is significantly reduced.

ところが、本実施の形態のように、上述の最良の実施の形態１に係る細径伝熱管ユニット４，４・・・よりなる細径多管式熱交換器１の構成において、伝熱管４１，４１・・・の管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・を空気流Ｆの下流側（伝熱フィン４２の後縁側）に偏位させると、その分前縁部分での内部流体との温度差が小さくなり、フィン効率が低下するので、着霜進度が低下し、デフロスト周期を長期化させることができる。 However, as in the present embodiment, in the configuration of the small-diameter multi-tube heat exchanger 1 including the small-diameter heat transfer tube units 4, 4... According to the above-described best embodiment 1, the heat transfer tubes 41, When the tube portions 41a, 41b, 41b, 41a,... 41 are displaced to the downstream side of the air flow F (the rear edge side of the heat transfer fins 42), the internal fluid at the front edge portion is increased accordingly. Since the temperature difference between the two becomes smaller and the fin efficiency is lowered, the frosting progress is lowered and the defrost cycle can be prolonged.

その結果、熱交換性能の向上につながる。 As a result, the heat exchange performance is improved.

（最良の実施の形態３）
次に図８は、本願発明を実施するに際しての最良の実施の形態３に係る細径多管式熱交換器の細径伝熱管ユニットの構造を示している。 (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.

この最良の実施の形態の構成では、上述の最良の実施の形態１に係る細径伝熱管ユニット４，４・・・よりなる細径多管式熱交換器１の構成において、細径伝熱管４１，４１・・・の管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・を空気流Ｆの上流側（伝熱フィン４２の前縁側）に偏位させ、空気調和機の室内機の熱交換器として採用した時に最適なものとなるように構成したことを特徴とするものである。 In the configuration of the best embodiment, in the configuration of the small diameter multi-tube heat exchanger 1 including the small diameter heat transfer tube units 4, 4... The tube portions 41a, 41b, 41b, 41a,... Of 41, 41... Are displaced to the upstream side of the air flow F (the front edge side of the heat transfer fins 42), and heat exchange of the indoor unit of the air conditioner It is characterized by being configured so as to be optimal when used as a vessel.

空気調和機用室内機の熱交換器の場合、伝熱フィン４２，４２・・・の後縁側で凝縮水の飛散を生じやすい問題がある。 In the case of a heat exchanger for an air conditioner indoor unit, there is a problem that condensate is likely to be scattered on the rear edge side of the heat transfer fins 42, 42.

ところが、本実施の形態のように、上述の最良の実施の形態１に係る細径伝熱管ユニット４，４・・・よりなる細径多管式熱交換器１の構成において、伝熱管４１，４１・・・の管体部４１ａ，４１ｂ、４１ｂ，４１ａ・・・を空気流Ｆの上流側（伝熱フィン４２の前縁側）に偏位させると、その分後縁部分の長さが長くなり、後縁側の空気の流れがスムーズに整流される。その結果、凝縮水の飛散が防止される。 However, as in the present embodiment, in the configuration of the small-diameter multi-tube heat exchanger 1 including the small-diameter heat transfer tube units 4, 4... According to the above-described best embodiment 1, the heat transfer tubes 41, When the tube portions 41a, 41b, 41b, 41a,... 41 are displaced to the upstream side of the air flow F (the front edge side of the heat transfer fins 42), the length of the rear edge portion is increased accordingly. Thus, the air flow on the trailing edge side is smoothly rectified. As a result, scattering of condensed water is prevented.

（その他の最良の実施の形態）
なお、以上のような細径伝熱管ユニット４は、例えば前述の図１４に示すように、管体部４１ａ，４１ｂと該管体部４１ａ，４１ｂの両側に設けられたＵ状のカシメ部４１ｅ，４１ｆ、４１ｅ，４１ｆにカシメ固定された１枚板構造の伝熱フィンプレート４２ａ，４２ｂ，４２ｃによっても、全く同様に形成することができる。 (Other best embodiments)
The small-diameter heat transfer tube unit 4 as described above includes, for example, tube portions 41a and 41b and U-shaped crimp portions 41e provided on both sides of the tube portions 41a and 41b as shown in FIG. , 41f, 41e, and 41f can be formed in exactly the same manner by the heat transfer fin plates 42a, 42b, and 42c having a single plate structure that is fixed by caulking.

本願発明の最良の実施の形態１に係る細径多管式熱交換器の細径伝熱管ユニットの構成を示す斜視図である。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. 同細径伝熱管ユニットの要部の拡大斜視図である。It is an expansion perspective view of the principal part of the same small diameter heat exchanger tube unit. 同細径伝熱管ユニットの断面図（図１のＡ−Ａ）である。It is sectional drawing (AA of FIG. 1) of the same small diameter heat exchanger tube unit. 同細径伝熱管ユニットの左右貼り合わせ部材（ａ），（ｂ）の貼り合わせ前の対向面（接合面）の構造を左右に対比して示す図である。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. 同細径伝熱管ユニットを用いて構成した細径多管式熱交換器の斜視図である。It is a perspective view of the thin diameter multi-tube heat exchanger comprised using the same thin diameter heat exchanger tube unit. 同細径多管式熱交換器の熱交部の構成を示す水平断面図である。It is a horizontal sectional view which shows the structure of the heat exchange part of the same small diameter multi-tube heat exchanger. 本願発明の最良の実施の形態２に係る細径多管式熱交換器の熱交部の構成を示す斜視図である。It is a perspective view which shows the structure of the heat exchange part of the thin diameter multi-tube heat exchanger which concerns on the best Embodiment 2 of this invention. 本願発明の最良の実施の形態３に係る細径多管式熱交換器の熱交部の構成を示す斜視図である。It is a perspective view which shows the structure of the heat exchange part of the small diameter multitubular heat exchanger which concerns on the best Embodiment 3 of this invention. 従来の細径伝熱管ユニットを用いて構成した細径多管式熱交換器の構成を示す斜視図である。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. 同細径多管式熱交換器を構成する細径伝熱管ユニットの左右貼り合わせ部材（ａ），（ｂ）の貼り合わせ前の対向面（貼り合わせ面）の構造を左右に対比して示す図である。The structure of the opposing surface (bonding surface) before bonding of the left and right bonded members (a) and (b) of the small diameter heat transfer tube unit constituting the same small diameter multi-tube heat exchanger is shown in comparison with the left and right. FIG. 同細径多管式熱交換器の細径伝熱管ユニット部の構成を示す水平断面図である。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. 同細径多管式熱交換器の熱交部の構成を示す水平断面図である。It is a horizontal sectional view which shows the structure of the heat exchange part of the same small diameter multi-tube heat exchanger. 同細径多管式熱交換器の熱交部の変形例の構成を示す水平断面図である。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. 同細径多管式熱交換器の細径伝熱管ユニットの変形例の構成を示す一部切欠斜視図である。It is a partially notched perspective view which shows the structure of the modification of the thin diameter heat exchanger tube unit of the same thin diameter multi-tube heat exchanger.

Explanation of symbols

１は細径多管式熱交換器、２Ａは入口ヘッダ、２Ｂは出口ヘッダ、３は熱交部、４は細径伝熱管ユニット、４１は細径伝熱管ユニット４のＵ状の伝熱管、４１ａ，４１ｂは管体部、４２は伝熱フィン、４２ａ，４２ｂ，４２ｃは伝熱フィン４２のフィン部、４３ａ，４３ｂはスリットである。
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 tube parts, 42 is a heat transfer fin, 42a, 42b and 42c are fin parts of the heat transfer fin 42, and 43a and 43b are slits.

Claims

Two rows of thin tube portions (41a) and (41b) for allowing heat exchange between the internal fluid and the external fluid F are provided on both sides of the tube portions (41a) and (41b). A small diameter formed by arranging a plurality of small diameter heat transfer tube units (4) composed of heat transfer fins (42a), (42b), (42c) in parallel with the direction in which the external fluid F flows, with a predetermined interval. A small-diameter heat transfer tube unit of a multi-tube heat exchanger, in which the tube portions (41a) and (41b) are arranged in a staggered structure, and at the upstream or downstream side of the external fluid F when the staggered arrangement is performed. By expanding the fin width on the downstream side or the upstream side of the external fluid F of the heat transfer fins (42a), (42b), (42c) that are displaced, their end faces are aligned in the same end face state. A small-diameter heat transfer tube unit for the small-diameter multi-tube heat exchanger.

Of the heat transfer fins (42c) or (42a) located on the outer peripheral side of the tube portion (41b) or (41a) on either one side of the thin tube portions (41a) and (41b) in two rows in the front and rear direction The fin width W ₁ is formed to be larger than the fin width W _{2 of the} heat transfer fin (42a) or (42c) located on the outer peripheral side of the other tube portion (41a) or (41b). Item 2. A small-diameter heat transfer tube unit of the small-diameter multitubular heat exchanger according to item 1.

The positions of the tube portions (41a), (41b), (41b), (41a)... Are changed to the heat transfer fins (42a), (42b), (42c), (42c), (42b), (42a). ) ... By deviating to the rear edge side, the heat transfer fins (42a), (42b), (42c), (42c), (42b), (42a) ... the width of the front edge is increased. 4. The thin diameter multi-pipe heat exchanger according to claim 1, wherein frost formation is delayed by lowering the fin efficiency of the external fluid F inflow portion. Heat tube unit.

The positions of the tube portions (41a), (41b), (41b), (41a)... Are changed to the heat transfer fins (42a), (42b), (42c), (42c), (42b), (42a). )... To the front edge side of the heat transfer fins (42a), (42b), (42c), (42a), (42b), (42c) 4. The small diameter heat transfer tube unit of the small diameter multitubular heat exchanger according to claim 1, wherein condensate is prevented from splashing by rectifying the flow of the fluid F outflow portion.

The heat exchanger is for a refrigerating 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. The thin-diameter heat transfer tube unit of the thin-diameter multitubular heat exchanger according to claim 1, 2, 3, or 4.