JP2009097810A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of a conventional technology, wherein, since a previously coated brazing material is poured into a recessed part formed in the outer surface of a core tube (a heat transfer tube) and a coiled tube is arranged above the recessed part to cover the recessed part, unevenness is easily caused in positioning of the recessed part and the coiled tube, and wherein, since a protruding shape is machined in order from an end of the heat transmitting tube when forming the protrusion in the inner surface of the heat transmitting tube, it takes long time to manufacture the tube. <P>SOLUTION: This heat exchanger has: a heat transfer tube 1 formed with a spiral crest and trough part on the outer surface and the inner surface thereof and provided with an irregular part 7 in the spiral angular part 6 in the inner surface; and a coiled tube 4 spirally wound around the outer surface of the heat transfer tube 3 along the trough part 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat exchanger, and more particularly to a heat exchanger in which a wound tube is wound around a heat transfer tube in which spiral ridges and valleys are formed on an outer surface and an inner surface.

  As a conventional heat exchanger, a heat exchanger that exchanges heat between a first fluid and a second fluid, forming a flow path for the first fluid, and pressing the outer surface to cause protrusions on the inner surface. A core tube (heat transfer tube) formed on the outer surface and having a recessed portion formed thereon, a flow path for the second fluid, and a wound tube wound around the outer surface of the core tube; And a brazing material poured into the recess (see, for example, Patent Document 1).

Japanese Patent Laying-Open No. 2006-317115 (first page, FIG. 5)

  The conventional technology as described above has a configuration in which a brazing material previously applied is poured into a recess formed on the outer surface of the core tube, and the winding tube is disposed in a state of covering the recess just above. However, in this configuration, since there is no means for fixing the position of the winding tube, there is a problem that the positioning of the recess and the winding tube is likely to vary, and there is a high possibility of causing a variation in performance. In addition, as a means for forming protrusions on the inner surface of the heat transfer tube, it is necessary to sequentially process a predetermined protrusion shape from the end of the heat transfer tube, resulting in a problem that the manufacturing time becomes long.

  The present invention has been made in order to solve the above-described problems of the prior art, has little variation in performance, is improved in performance, and can be easily performed without increasing the manufacturing time even in a conventional manufacturing facility. The purpose is to obtain a heat exchanger that can be manufactured easily.

  In the heat exchanger according to the present invention, spiral peaks and valleys are formed on the outer surface and the inner surface of the heat transfer tube used as the core tube, respectively, and irregularities are further formed on the spiral peaks on the inner surface. A winding tube spirally wound around a trough portion on the outer surface side of the heat transfer tube in which irregularities are formed in the ridge portion on the inner surface is provided.

  According to this invention, since the unevenness | corrugation is further formed in the helical peak part in the inner surface of a heat exchanger tube, a heat-transfer area is expanded and the performance of a heat exchanger is improved. In addition, the unevenness provided in the peak portion of the inner surface is formed in the same manner with a conventional manufacturing apparatus except that a mandrel having an unevenness corresponding to the unevenness is used on the outer peripheral surface as a mandrel used when manufacturing the heat transfer tube. Therefore, it is not necessary to change the manufacturing process and the manufacturing time is not prolonged. In addition, since the irregularities formed on the inner surface of the heat transfer tube are always located in the spiral valley formed on the outer surface of the heat transfer tube, the contact position with the winding tube wound around the valley of the outer surface of the heat transfer tube is constant. Thus, it is possible to reduce the variation in performance, which has an unprecedented remarkable effect.

Embodiment 1 FIG.
1 to 3 illustrate a heat exchanger according to Embodiment 1 of the present invention. FIG. 1 is a perspective view showing a main part of a twisted tube heat exchanger, and FIG. FIG. 3 is a partially broken perspective view showing the internal structure of the shown heat transfer tube, FIG. 3 is a view showing a mandrel with protrusions used when manufacturing the heat transfer tube shown in FIG. 1, (a) is an external perspective view, b) is an enlarged front view seen from the axial direction. Note that the same reference numerals denote the same or corresponding parts throughout the drawings. In the figure, the heat exchanger 10 includes a heat transfer tube 1 composed of a twisted tube in which a plurality of ridges 2 and valleys 3 are continuously provided in a spiral shape on each outer surface (three in this example), A winding tube 4 (41, 42, 43) wound and fitted along the valley portion 3 of the heat transfer tube 1 is provided.

  The heat transfer tube 1 constitutes a core tube for the winding tube 4 and is used as the first fluid piping, and the winding tube 4 is used as the second fluid piping. As shown in FIG. 2, the inner surface of the heat transfer tube 1 has a valley portion 5 corresponding to the peak portion 2 on the outer surface and a peak portion 6 corresponding to the valley portion 3 on the outer surface. And the unevenness | corrugation 7 is formed in the circumferential direction at the predetermined | prescribed pitch in the peak part 6 on the said inner surface side. The unevenness 7 is composed of a concave portion 71 and a convex portion 72 formed in a groove shape extending in the axial direction, that is, the longitudinal direction of the heat transfer tube 1, and is formed in a spiral shape in the circumferential direction on each mountain portion 6 on the inner surface side. Yes.

  Next, the manufacturing method of the said heat exchanger tube 1 is demonstrated. In order to manufacture the above-described twisted tube type heat transfer tube 1, basically, a mandrel is inserted into a copper tube (smooth tube) in the same manner as in the conventional manufacturing method, and after twisting, the mandrel is pulled out. It is manufactured by. In the first embodiment of the present invention, a mandrel 8 with protrusions shown in FIG. 3 is used as the mandrel. In other words, the mandrel with protrusions 8 includes a plurality of convex portions 81 and concave portions 82 formed on the outer peripheral surface at intervals of a predetermined angle θ1. In this example, 12 convex portions 81 are provided on the outer peripheral surface, and the step between the convex portion 81 and the concave portion 82 is set to 0.5 mm. As in the conventional manufacturing process, the heat transfer tube 1 constituting the first fluid pipe is inserted into a copper tube (not shown) and twisted, and then the mandrel 8 with protrusions is pulled out. Manufactured by.

  The projections and depressions 82 of the projection mandrel 8 are respectively transferred to the projections and depressions 7 formed of the depressions 71 and the projections 72 spirally formed in the circumferential direction on the crest 6 on the inner surface of the heat transfer tube 1. In this example, 12 convex portions 72 and one concave portion 71 are formed per circumference. In addition, a plurality of rollers (not shown) are pressed against the plurality of valleys 3 formed on the outer peripheral portion of the copper tube at the time of the twisting, so that the transfer can be surely performed. It can be. In addition, the conventional mandrel is a metal round bar (not shown) having a circular cross section, and when the round mandrel is inserted into a copper tube, twisted and then pulled out, the inner surface of the copper tube Spiral peaks and valleys are formed of smooth irregularities similar to the outer surface.

  Next, the operation of the heat exchanger configured as described above will be described. The heat transfer tube 1 used as the first fluid piping of the heat exchanger 10 has spiral peaks 2 and valleys 3 having a predetermined pitch on the outer surface alternately, and peaks on the inner surface corresponding to the valleys 3 on the outer surface. The portion 6 has the concave and convex portions 7 including the concave portion 71 and the convex portion 72, and the three winding tubes 41, 42, and 43 are wound along the outer trough portion 3, so that the inner surface of the heat transfer tube 1 is spaced at a constant interval. The winding tube 4 can be surely arranged directly above the irregularities 7 formed by the concave portions 71 and the convex portions 72 formed at the angles, and variations in performance are suppressed. Moreover, since the surface area which contributes to heat transfer is expanded because the heat transfer tube 1 is provided with the unevenness 7 including the concave portion 71 and the convex portion 72 on the inner surface, when the heat transfer tube 1 is used as the first fluid pipe, Furthermore, heat exchange with the wound tube 4 used as the second fluid piping is improved, and the heat exchanger performance is improved. In addition, the kind of fluid (gas, liquid) flowing through the heat transfer tube 1 and the winding tube 4 (41, 42, 43) is not particularly limited, for example, a refrigerant used in a refrigeration cycle such as an air conditioner, Any of hot water, water, bath water, and the like used for a water heater, a heater, etc. can be preferably used without any particular limitation.

FIG. 4 is a characteristic diagram showing the heat exchanger performance measured for the heat exchanger obtained in the first embodiment in comparison with the heat exchanger according to the prior art, and the horizontal axis is the inner surface area (mm) of the heat transfer tube. ² ), the vertical axis represents the heat exchanger performance (W / K). In FIG. 4, a horizontal straight line L drawn with a vertical axis scale of 1300 W / K indicates the product specifications (reference values) of the heat exchanger performance. The performance curve A is the case of the heat exchanger 10 obtained by Embodiment 1, and the point A1 shows the case where the number of the convex parts 72 is 8, and the point A2 shows the case where the number of the convex parts 72 is 16. . In addition, the point B is the case (comparative example) of the conventional heat exchanger manufactured using the mandrel of a round bar shape.

As is clear from FIG. 4, the heat exchanger performance of the heat exchanger manufactured using the conventional mandrel is about 1305 W / K shown in point B, whereas the mandrel with protrusions of the first embodiment is used. As for the heat exchanger performance of the heat exchanger 10 manufactured using 8, when the number of convex portions 72 is set to 8, the inner surface area of the heat transfer tube 1 is about 73 mm ^{2 as} indicated by a point A1, The heat exchanger performance was about 1350 W / K. Similarly, when the number of convex portions 72 was set to 16, the inner surface area of the heat transfer tube 1 was 76 mm ² , and the heat exchanger performance was about 1390 W / K as indicated by point A2. In addition, as a result of performing the same performance test by changing the number of the convex portions 72, the number of the convex portions 72 is in the range of 8 to 16 per circumference, compared with the performance of the conventional heat exchanger. It was found that the heat exchanger performance was improved by 3.5 to 6.5%. The number of the convex portions 72 is not particularly limited, and may be, for example, 7 or less, or 17 or more. However, the degree of improvement in the heat exchanger performance is reduced, so that it is within the above range. Is preferred.

  As described above, according to the first embodiment, the ridges 6 corresponding to the valleys 3 on the outer surface on the inner surface of the heat transfer tube 1 are provided with the concave and convex portions 7 including the concave portions 71 and the convex portions 72. The heat transfer area can be expanded, and the performance of the heat exchanger 10 can be improved. Further, when manufacturing the heat transfer tube 1 having the uneven surface 7 on the inner surface as described above, by using the mandrel 8 with a protrusion, for example, even in a conventional manufacturing facility, the manufacturing time can be extended without changing the manufacturing process. And can be easily manufactured. Moreover, since this unevenness | corrugation 7 is always provided in the position corresponding to the spiral trough part 3 in the outer surface of the heat exchanger tube 1 used as 1st fluid piping, the winding pipe 4 ( 41, 42, 43), the contact position is constant, and performance variations can be reduced. Furthermore, since the performance of the heat exchanger is improved, a remarkable effect that has not been achieved in the past can be obtained by reducing the length of the heat exchanger so that the cost can be reduced. Moreover, by setting the number of convex portions 72 formed on the inner surface of the heat transfer tube 1 within a range of 8 to 16, the heat transfer area inside the heat transfer tube 1 can be expanded, and the heat exchanger performance can be improved.

Embodiment 2. FIG.
5 and 6 illustrate a heat exchanger according to Embodiment 2 of the present invention, and FIG. 5 is a partially broken perspective view showing an internal structure of a heat transfer tube constituting the heat exchanger, FIG. These are figures which show the polygonal mandrel used when manufacturing the heat exchanger tube shown by FIG. 5, (a) is an external appearance perspective view, (b) is the enlarged front view seen from the axial direction. In the figure, the peak portion 6 on the inner surface of the heat transfer tube 1A has a V-shaped valley shape with a wide angle formed between the planar convex portion 72A corresponding to one side of the polygon and the adjacent convex portions 72A. The concaves and convexes 7A composed of the concave parts 71A are formed in a spiral shape at an angle of a constant interval in the circumferential direction. Other configurations are the same as those of the first embodiment shown in FIGS.

  In order to obtain the heat transfer tube 1A, a polygonal mandrel 8A shown in FIG. 6 is used. In FIG. 6, a polygonal mandrel 8A has an inscribed circle on the outer peripheral surface corresponding to the outer dimension of a conventional mandrel having a circular cross section, and has a planar side part (corresponding to a concave part) 82A with a side angle θ2 of a constant interval. And a ridge line-like ridge portion (corresponding to a convex portion) 81A. As in the first embodiment, the heat transfer tube 1A inserts the polygonal mandrel 8A into a copper tube (smooth tube) (not shown), twists it, and then pulls out the polygonal mandrel 8A. Manufactured by. The unevenness 7A formed on the peak portion 6 on the inner surface of the heat transfer tube 1A is obtained by transferring the side portion 82A and the ridge portion 81A of the outer peripheral surface of the polygonal mandrel 8A, and the portion corresponding to the side portion 82A is a convex portion. A portion corresponding to 72A and ridge 81B is transferred as a recess 71A. In this example, 12 convex portions 72A / circumference are formed.

  Next, the operation will be described. As in the first embodiment, the heat transfer tube 1A has spiral peaks 2 and valleys 3 having a predetermined pitch on the outer surface alternately, and is recessed in the peaks 6 on the inner surface corresponding to the valleys 3 on the outer surface. An uneven surface 7A composed of 71A and a convex portion 72A is formed, and the three winding tubes 4 (41, 42, 43) are wound along the three spiral valleys 3 provided on the outer surface side. The winding tube 4 can be surely disposed directly above the unevenness 7A composed of the concave portion 71A and the convex portion 72A formed in the above, and variations in performance are suppressed. Further, the heat transfer tube 1A has a surface area enlarged by providing the inner surface with the unevenness 7A, and when the heat transfer tube 1A is used as the first fluid piping, heat exchange with the winding tube 4 used as the second fluid piping is performed. Is improved and the performance of the heat exchanger is improved.

FIG. 7 is a characteristic diagram similar to FIG. 4 showing the heat exchanger performance measured for the heat exchanger obtained by Embodiment 2 above in comparison with a heat exchanger according to the prior art, in which the horizontal axis , The vertical axis, the straight line L, and the point B are the same as in FIG. The performance curve C is the case of the heat exchanger (not shown) obtained by the second embodiment, and the point C1 is the number of the convex portions 72A on the inner surface of the heat transfer tube 1A is 8 pieces / round, and the point C2 is the convex portion The case where the number of 72A is 24 / round is shown. As is clear from FIG. 7, the performance curve C of the heat exchanger using the heat transfer tube 1A manufactured using the polygonal mandrel 8A as the first fluid piping has the number of convex portions 72A set to eight. In this case, the inner surface area of the heat transfer tube 1A was 73 mm ² , and the heat exchanger performance was about 1320 W / K as plotted at the point C1. Similarly, when the number of convex portions 72A was set to 24, the inner surface area of the heat transfer tube 1A was 76 mm ² , and the heat exchanger performance was 1350 W / K as plotted at point C2.

  In addition, as a result of performing the same performance test by changing the number of the convex portions 72A on the inner surface of the heat transfer tube 1A, the number of the convex portions 72A is set in the range of 8 to 24, thereby improving the heat exchanger performance to 1320. It can be set to 1350 W / K, and it has been found that the heat exchanger performance is improved by 1.2 to 3.5% as compared with the heat exchanger performance of the conventional heat exchanger. Note that the number of the convex portions 72A is not particularly limited, and may be, for example, 7 pieces / circumference or less, or 25 pieces / circumference or more. However, since the degree of improvement in the heat exchanger performance is reduced, the above range. It is preferable to be inside.

  As described above, according to the second embodiment, the concave portion 71A and the convex portion 72A are provided on the inner surface ridge portion 6 corresponding to the outer valley portion 3 in the heat transfer tube 1A used as the first fluid piping of the heat exchanger. By providing the polygonal unevenness 7A, the heat transfer area can be expanded and the performance of the heat exchanger can be improved. Further, when manufacturing such a heat transfer tube 1A, for example, a polygonal mandrel 8A is obtained by applying a polygonal shape to the outer peripheral surface of a normal mandrel having a circular cross section, for example, manufacturing a conventional twisted tube heat transfer tube It can be easily manufactured in a short time without changing the process. Further, since the unevenness 7A formed on the inner surface of the heat transfer tube 1A is always provided in the spiral valley portion 3 formed on the outer surface of the heat transfer tube 1A, the winding wound around the valley portion 3 that is the spiral groove of the heat transfer tube 1A. The position of contact with the tube 4 is constant, and variations in performance can be reduced. Furthermore, since the heat exchanger performance can be improved, the length of the heat exchanger can be shortened, and if it is shortened, the cost can be reduced and an unprecedented remarkable effect can be obtained. Can do. Moreover, by setting the number of convex portions 72A on the inner surface of the heat transfer tube 1A within a range of 8 to 24 pieces / circumference, the heat transfer area inside the heat transfer tube 1A can be expanded, and the heat exchanger performance can be improved.

  By the way, in the said embodiment, as unevenness | corrugation formed in the helical peak part 6 in the inner surface side of a heat exchanger tube, unevenness | corrugation 7 (embodiment 1) of cross-sectional substantially gear shape, and uneven | corrugated 7A (embodiment of cross-section) Although the case where the form 1) is provided is illustrated, it is needless to say that the shape of the unevenness is not limited thereto. Moreover, although the helical peak part 2 (or trough part 3) formed in the surrounding surface of a heat exchanger tube demonstrated the case where it was 3, it does not necessarily need to be 3 lines. Therefore, the number of winding tubes 4 is not limited to three. Further, it is natural that the step between the convex portion 81 and the concave portion 82 of the mandrel 8 with protrusions is not limited to that exemplified in the embodiment.

The perspective view which shows the principal part of the heat exchanger which concerns on Embodiment 1 of this invention. The partially broken perspective view which shows the internal structure of the heat exchanger tube shown by FIG. It is a figure which shows the mandrel with a protrusion used when manufacturing the heat exchanger tube shown by FIG. 1, (a) is an external appearance perspective view, (b) is the enlarged front view seen from the axial direction. The characteristic view which shows the heat exchanger performance measured about the heat exchanger obtained by Embodiment 1 compared with the heat exchanger by a prior art. The partially broken perspective view which shows the internal structure of the heat exchanger tube which comprises the heat exchanger which concerns on Embodiment 2 of this invention. It is a figure which shows the polygonal mandrel used when manufacturing the heat exchanger tube shown by FIG. 5, (a) is an external appearance perspective view, (b) is the enlarged front view seen from the axial direction. The characteristic view which shows the heat exchanger performance measured about the heat exchanger obtained by Embodiment 2 compared with the heat exchanger by a prior art.

Explanation of symbols

  1, 1A heat transfer tube, 2 peaks, 3 valleys, 4 (41, 42, 43) 2nd fluid piping, 5 valleys, 6 peaks, 7, 7A irregularities, 71, 71A depressions, 72, 72A projections 8 Protruding mandrel, 81 convex portion, 82 concave portion, 8A polygonal mandrel, 81A ridge portion (corresponding to convex portion), 82A side portion (corresponding to concave portion), 10 heat exchanger.

Claims (5)

  A heat transfer tube in which spiral peaks and valleys are formed on the outer surface and the inner surface, respectively, and irregularities are formed on the spiral peaks on the inner surface, and a spiral shape along the valley on the outer surface of the heat transfer tube A heat exchanger characterized by comprising a winding tube wound around.   2. The heat exchanger according to claim 1, wherein the unevenness is formed by transferring an outer peripheral surface of a mandrel with a projection having a substantially gear-shaped cross section used as a core material when twisting a smooth tube.   The heat exchanger according to claim 2, wherein the number of the convex and concave portions is 8 to 16 per circumference.   2. The heat exchanger according to claim 1, wherein the irregularities are formed by transferring an outer peripheral surface of a polygonal mandrel having a polygonal cross section used as a core material when twisting a smooth tube.   5. The heat exchanger according to claim 4, wherein the number of the convex and concave portions is 8 to 24 per circumference.

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