JP5753355B2 - Heat transfer tube for fin-and-tube heat exchanger, fin-and-tube heat exchanger using the same, and manufacturing method thereof - Google Patents

Description

  The present invention relates to a heat transfer tube for a fin-and-tube heat exchanger, a fin-and-tube heat exchanger using the heat transfer tube, and a manufacturing method thereof, and more particularly to a fin in an air conditioner such as a home air conditioner or a packaged air conditioner. The present invention relates to a heat transfer tube suitably used for an AND tube type heat exchanger, a fin and tube type heat exchanger using the heat transfer tube, and a method of advantageously manufacturing the same.

  Conventionally, in addition to air conditioning equipment such as home air conditioners, automotive air conditioners, and packaged air conditioners, refrigerators, heat pump water heaters, and the like have used heat exchangers that operate as evaporators or condensers, among them. In home indoor air conditioners and commercial packaged air conditioners, fin-and-tube heat exchangers having a structure in which fins are assembled to heat transfer tubes are most commonly used.

  In recent years, heat exchangers using natural refrigerants with low global warming potential have been developed in place of conventional chlorofluorocarbon refrigerants from the viewpoint of protecting the ozone layer and preventing global warming. Hot water heaters using refrigerants mainly composed of carbon dioxide gas have attracted attention and have been developed. The same fin-and-tube heat exchangers as those described above are used for the air heat exchangers. It has been.

  By the way, such a fin-and-tube heat exchanger generally has a structure in which heat transfer tubes are inserted in a direction perpendicular to a plurality of fins (outer surface fins) and the plurality of fins and the heat transfer tubes are joined. Has been put to practical use. In the heat exchanger having such a structure, the refrigerant is circulated in the heat transfer tube, while air as a heat exchange fluid is caused to flow along the plurality of fins in a direction perpendicular to the heat transfer tube. Thus, heat exchange is performed between the refrigerant and the air.

  The fins constituting the fin-and-tube heat exchanger are generally made of a plate material made of aluminum or an aluminum alloy, and the surface of the fins is not flat but slits or A material that has been processed into a shape having a heat transfer promoting effect, such as a louver, is often used. Further, those having a coating film made of a hydrophilic or water-repellent resin on the surface of such fins are often used. By forming such a resin coating film, when the fin-and-tube heat exchanger is operated for use in an air conditioner such as a home air conditioner or a packaged air conditioner, the condensed water generated on the fin surface is reduced. A uniform water film can be smoothly dropped and discharged, and the ventilation resistance due to the condensed water can be reduced to maintain the performance of the heat exchanger.

  As is well known, as a heat transfer tube used in a fin-and-tube heat exchanger, a round tube having a circular shape in a cross section perpendicular to the tube axis is generally adopted. Yes. And in such a circular cross-sectional shape (round tube), many materials such as copper and copper alloy, or aluminum and aluminum alloy are adopted as the material, and many grooves such as tubes are formed on the inner surface. There are many so-called inner surface grooved heat transfer tubes in which many spiral grooves are formed so as to extend with a predetermined lead angle with respect to the shaft, and inner surface fins having a predetermined height are formed between the grooves. It is used.

  And when such a heat exchanger tube is exhibiting circular cross-sectional shape, a fin and tube type heat exchanger will be manufactured by the following well-known processes, for example. That is, first, an aluminum plate fin in which a plurality of predetermined assembly holes are formed is formed by press working or the like, and after the obtained aluminum plate fins are stacked, separately in the assembly hole, Insert the manufactured heat transfer tube. As the heat transfer tube used here, for example, a tube that has been subjected to processing such as grooving on the inner surface by rolling or the like, and subjected to regular cutting and hairpin bending is provided. Then, by expanding the heat transfer tube, the step of fixing the aluminum plate fin and brazing the U-bend tube at the end of the heat transfer tube opposite to the side subjected to the hairpin bending process is performed. After that, a fin-and-tube heat exchanger is manufactured.

  By the way, in order to improve the heat transfer performance of such a fin-and-tube heat exchanger, various efforts have been made so far. By adding various improvements to the form, the heat transfer coefficient in the pipe has been greatly improved, and the heat transfer performance of the heat exchanger has been improved. However, in the fin-and-tube heat exchanger, the heat transfer between the heat transfer tube and the aluminum fin is very important as well as the heat transfer in the tube of the heat transfer tube. It has been found that heat transfer between the fins is greatly influenced by the degree of adhesion between the heat transfer tubes and the aluminum fins, that is, their contact thermal resistance.

  However, in the case of heat transfer tubes made of copper, copper alloys, aluminum or aluminum alloys that have been generally used in the past, even if the outer surface is macroscopically smooth, it is viewed microscopically. And there are fine irregularities. On the other hand, the surface of the aluminum fin combined with this also has fine irregularities, and when these are assembled, it appears that they are in good contact with each other, but they can be seen microscopically. In other words, it is a partial contact, and there are many voids, and the contact area is not sufficient. For this reason, the contact thermal resistance is increased, and the heat transfer between the heat transfer tube and the aluminum fin is not sufficient.

  Therefore, in order to reduce such voids and improve the heat transfer performance of the heat exchanger, Japanese Patent Application Laid-Open No. 56-133595 (Patent Document 1) forms an organic coating on the surface of the heat transfer tube. However, a cross fin type heat exchanger in which a heat transfer tube is inserted into a hole of a fin group and expanded is disclosed. According to such a cross fin type heat exchanger, the organic coating moves to the minute gap between the fin group and the heat transfer tube by the pipe expansion, and the contact between both can be remarkably improved. However, the organic coating used there is an organic coating that is viscous at room temperature. However, in a situation where a refrigerant having a temperature higher than room temperature flows in the heat transfer tube, the coating flows out. The problem was caused. Here, the term “viscousness” means a state of deformation at that temperature when a force is applied.

  In order to solve such a problem, in Japanese Patent Application Laid-Open No. 2004-125235 (Patent Document 2), heat in which a resin layer in which at least a part is solidified or hardened exists between the heat transfer tubes and the fins. The exchanger and its manufacturing method has been clarified. According to such a heat exchanger, after forming a fluid resin layer or the like on at least a part of the outer surface of the heat transfer tube, the tube is expanded while the progress of solidification or curing is small. The diameter of the heat transfer tube is enlarged, and the resin or the like on the surface of the heat transfer tube is in contact with the fins to fill at least part of the gap. And this resin etc. will be heated by a subsequent drying process or brazing, and the resin etc. will be hardened in the state where contact with a heat exchanger tube and a fin was maintained. Thereby, the heat transfer performance of the heat exchanger can be improved.

  However, the heat exchanger disclosed in Patent Document 2 and the manufacturing method thereof have the following problems and cannot be said to be satisfactory. That is, the step of assembling the heat transfer tube to the aluminum fin, that is, after laminating the aluminum fin, the heat transfer tube is inserted into the assembly hole formed in the aluminum fin, and the heat transfer tube is expanded and fixed to the aluminum fin. In the process, since the resin layer applied to the outer surface of the heat transfer tube is in a viscous state, as in the case of Patent Document 1, the heat transfer tube in such a state is inserted into the assembly hole of the aluminum fin. Then, the resin layer is scraped off by contacting the inner surface of the assembly hole, and there is a possibility that the resin filling the gap between the fin and the heat transfer tube is not sufficient. This is because there is usually very little clearance between the outer diameter of the heat transfer tube and the inner diameter of the assembly hole of the aluminum fin, and the outer surface of the heat transfer tube and the aluminum fin assembly hole rub against each other when inserting the heat transfer tube. Therefore, if the resin layer formed on the outer surface of the heat transfer tube is a viscous resin layer, it will be scraped off when it is rubbed. The part which cannot be filled up is made. In addition, when the resin layer application process is not performed immediately before the process of inserting the heat transfer tube into the aluminum fin, the heat transfer tube is handled or transported with the viscous resin layer applied to the outer surface. Therefore, the problem that the risk of the resin layer being scraped off during such work is high is also inherent.

JP-A-56-133595 JP 2004-125235 A

  Here, the present invention has been made in the background of such circumstances, and the problem to be solved is to reduce the contact thermal resistance between the heat transfer tube and the fin and improve the heat transfer performance. An object of the present invention is to provide a heat transfer tube used in a fin-and-tube heat exchanger that can be made to operate. The present invention also provides a fin-and-tube heat exchanger manufactured using such a heat transfer tube for a fin-and-tube heat exchanger and a method for manufacturing the same. , And the solution issue.

  In the present invention, in order to solve such problems, a fin-and-tube type heat inserted through an assembly hole provided in a fin made of aluminum or an alloy thereof and assembled by expansion. A heat transfer tube for an exchanger is formed on the outer surface of the heat transfer tube, and an adhesive coating made of an adhesive resin that is softened or melted by heating to 100 ° C. to 200 ° C. is formed. A heat exchanger tube for a fin-and-tube heat exchanger, characterized in that it can be fixed to the fin while filling the gap between the inner surface of the assembly hole, is there.

  Further, the present invention provides a heat transfer tube for a fin-and-tube heat exchanger that is inserted into an assembly hole provided in a fin made of aluminum or an alloy thereof and assembled by expansion of the tube. An adhesive coating film formed of a hot-melt adhesive resin having a melting point of ℃ to 200 ° C. is formed, and the adhesive coating film fills a gap between the inner surface of the assembly holes of the fin, The gist of the present invention is a heat transfer tube for a fin-and-tube heat exchanger, characterized in that it can be fixed to the fins.

  Furthermore, the present invention provides a heat transfer tube for a fin-and-tube heat exchanger, which is inserted through an assembly hole provided in a fin made of aluminum or an alloy thereof and assembled by expansion of the tube, An adhesive coating film made of a heat-reactive adhesive resin having a reaction temperature of ℃ to 200 ° C. is formed, and the adhesive coating film fills the gap between the fin assembly holes, The gist of the present invention is a heat transfer tube for a fin-and-tube heat exchanger, characterized in that it can be fixed to the fin.

  And in the present invention, a fin-and-tube heat exchanger is formed by inserting a heat transfer tube into an assembly hole provided in a fin made of aluminum or an alloy thereof, and assembled by expanding the tube, The heat transfer tube according to any one of claims 1 to 3 is used as a heat transfer tube, and an adhesive coating film formed on the outer surface of the heat transfer tube forms a gap between the fin assembly hole inner surfaces. A fin-and-tube heat exchanger, in which the heat transfer tube is fixed to the fin while filling the gap, is also the gist of the invention.

  In the present invention, an adhesive resin that is softened or melted by heating to 100 ° C. to 200 ° C. is applied to the outer surface of the heat transfer tube, and then held at a temperature lower than the temperature at which the adhesive resin softens or melts. A step of preparing a heat transfer tube in which the adhesive resin is dried and solidified, and an assembly hole provided in a fin made of aluminum or aluminum alloy formed by applying a hydrophilic paint or a water-repellent paint on the surface, After inserting the heat transfer tube, the step of expanding the heat transfer tube to produce an assembly, and maintaining the assembly at a temperature not lower than the temperature at which the adhesive resin softens or melts and not higher than 200 ° C. Then, the step of softening or melting the adhesive resin and filling the adhesive resin between the inner surface of the assembly hole of the fin and the outer surface of the heat transfer tube, and a set filled with the adhesive resin The body On the other hand, a process of completing an integrated fin-and-tube heat exchanger by holding the adhesive resin at a temperature not lower than room temperature and not higher than a temperature at which the adhesive resin is softened or melted, and solidifying the adhesive resin. And a manufacturing method of a fin-and-tube heat exchanger characterized by comprising:

  Furthermore, in the present invention, after applying a hot-melt adhesive resin having a melting point of 100 ° C. or more and 200 ° C. or less on the outer surface of the heat transfer tube, the temperature is kept below the melting point of the adhesive resin, A step of preparing a heat transfer tube obtained by drying and solidifying the adhesive resin, and an assembly hole provided in an aluminum or aluminum alloy fin formed by applying a hydrophilic paint or a water-repellent paint on the surface are provided in the heat transfer pipe. After inserting the heat tube, expanding the heat transfer tube to produce an assembly, and maintaining the assembly at a temperature not lower than the melting point of the adhesive resin and not higher than 200 ° C. Melting the resin, filling the adhesive resin between the inner surface of the fin assembly hole and the outer surface of the heat transfer tube, and cooling the assembly filled with the adhesive resin at room temperature. Above, the temperature below the melting point of the adhesive resin And completing the integrated fin-and-tube heat exchanger by solidifying the adhesive resin, and manufacturing method of the fin-and-tube heat exchanger Is the gist.

  Furthermore, in the present invention, after applying a heat-reactive adhesive resin having a reaction temperature of 100 ° C. or higher and 200 ° C. or lower to the outer surface of the heat transfer tube, the temperature is kept below the reaction temperature of the adhesive resin. Then, by drying the adhesive resin, a step of preparing a heat transfer tube in which an adhesive coating film is formed, and an aluminum or aluminum alloy made by applying a hydrophilic paint or a water-repellent paint on the surface After the heat transfer tube is inserted through the assembly hole provided in the fin, the heat transfer tube is expanded to produce an assembly, and the assembly forms the adhesive coating film. The adhesive resin is held at a temperature not lower than the reaction temperature and not higher than 200 ° C., and the adhesive resin is softened and filled between the inner surface of the assembly hole of the fin and the outer surface of the heat transfer tube. The resin is reacted and cured, and the integrated Also a method of manufacturing a fin-and-tube heat exchanger, characterized in that a step of completing the down-and-tube heat exchanger, with each other to its gist.

  Therefore, according to the heat transfer tube for a fin-and-tube heat exchanger configured in accordance with the present invention as described above, the attachment of the fin is performed by the adhesive coating film made of an adhesive resin formed on the outer surface of the heat transfer tube. The heat transfer tube for the fin-and-tube heat exchanger is configured so that the microscopic gap between the inner surface of the hole and the outer surface of the heat transfer tube is filled and the fins can be fixed to the heat transfer tube. Therefore, it is possible to effectively reduce the contact thermal resistance between the fin and the heat transfer tube and improve the heat exchange performance.

  Further, the adhesive coating film formed on the surface of the heat transfer tube is formed of an adhesive resin that softens, melts, or reacts when heated to 100 ° C. to 200 ° C. Even if a coating film or a water-repellent coating film is pre-coated, the heat transfer tube for fin-and-tube heat exchanger can be fixed by assembling the fin and heat transfer tube while keeping the function of the coating film good. Can be formed.

  If the heat transfer tube is an internally grooved heat transfer tube formed of aluminum or an aluminum alloy, the tube expansion rate at the time of mechanical expansion is increased in order to firmly fix the heat transfer tube and the fin. However, the internal fins of the heat transfer tube are crushed significantly, leading to a decrease in the heat transfer coefficient in the tube. According to the heat transfer tube for the fin-and-tube heat exchanger according to the present invention, the gap between the heat transfer tube and the fin is Since the coating film made of the adhesive resin is interposed, it is possible to reduce the expansion rate of the heat transfer tube and effectively suppress the collapse of the inner fins of the heat transfer tube.

  Furthermore, there is a fin-and-tube heat exchanger manufactured using a heat transfer tube for a fin-and-tube heat exchanger in which a predetermined adhesive coating film is formed on the outer surface of such a heat-transfer tube. Therefore, since the contact thermal resistance between the fin and the heat transfer tube is low, it is possible to exhibit a high heat exchange performance, and the hydrophilic coating film formed on the fin surface and the repellency. Since the effect of the water-based coating film is exhibited well, the condensed water on the fin surface generated when the heat exchanger is operated is smoothly discharged from the fin surface by the coating film, and the ventilation resistance due to the condensed water is reduced. It is possible to effectively suppress the increase and maintain high heat exchange performance stably.

  According to the method for manufacturing a fin-and-tube heat exchanger according to the present invention, the fin-and-tube heat exchanger can be maintained in a state in which the functions of the hydrophilic coating film and the water-repellent coating film formed on the fin surface are kept good. -A tube-type heat exchanger can be manufactured advantageously.

  In addition, in such a manufacturing method, since a fin having a hydrophilic coating or a water repellent coating applied in advance on its surface is used, a hydrophilic coating or a water repellent is applied to the fin surface after assembling the fin and the heat transfer tube. Compared to the post-coating method for forming a paint film, it is not necessary to prepare a paint tank or the like that can immerse the entire heat exchanger, so that the manufacturing cost can be advantageously reduced, It has the feature that the quality of the coating film formed on the fin can be improved.

  Furthermore, after assembling the fin and the heat transfer tube, it is not necessary to apply a hydrophilic paint or a water repellent paint to the fin, or to apply an adhesive or the like for fixing the fin to the heat transfer tube. The fin interval can be advantageously reduced, and as a result, the effect of reducing the size of the heat exchanger and improving the heat exchange performance is also exhibited.

It is a perspective explanatory view showing an example of a fin and tube type heat exchanger according to the present invention. It is front explanatory drawing which shows the fin which comprises the fin and tube type heat exchanger shown by FIG. It is a cross-sectional explanatory drawing which expands and shows the junction part of the fin and heat exchanger tube of the fin and tube type heat exchanger shown by FIG. It is sectional explanatory drawing which shows another example of the heat exchanger tube which comprises the fin and tube type heat exchanger according to this invention. It is a perspective explanatory view showing another example of the fin and tube type heat exchanger according to the present invention. It is sectional explanatory drawing which shows the form of the surface treatment of the fin material used in the Example. It is a perspective explanatory view showing roughly the fin and tube type heat exchanger used in the example. FIG. 8 is a schematic cross-sectional view showing the arrangement of the heat transfer tubes of the fin-and-tube heat exchanger shown in FIG. 7.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

  First, FIG. 1 schematically shows one embodiment of a fin-and-tube heat exchanger using a heat transfer tube for a fin-and-tube heat exchanger according to the present invention in the form of a perspective view. ing. In this case, the heat exchanger 10 is a set in which a plurality of heat transfer tubes (round tubes) 14 are provided on the fins 12 with respect to the plurality of fins 12 arranged in parallel with each other at a predetermined distance. It is formed by being inserted into and fixed to the attachment hole 16.

More specifically, the fin 12 is formed of a metal material made of aluminum or an aluminum alloy, as in the prior art, and has a rectangular plate shape as shown in FIG. The assembly holes 16, which are fins and into which the heat transfer tubes 14 are assembled, are formed so as to be arranged in a staggered manner in two rows in parallel with the longitudinal direction of the fins 12 from one end of the rectangular fins 12. Incidentally, the inner diameter of the assembling hole 16, depending on the outer diameter of the heat transfer tube 14 assembled, but is to be determined as appropriate, preferably, the inside diameter of the assembling hole 16: D ₂ is assembled by tube expansion Assuming that the outer diameter of the heat transfer tube 14 after tube expansion is D ₁ , it is preferable that D ₁ −D ₂ ≧ 0.08 mm is satisfied. By using the assembling holes 16 having such a size, it is possible to more effectively exert the contact thermal resistance reduction effect.

  Further, a collar portion 20 having a predetermined height is formed integrally with the fin 12 around the assembly hole 16. Further, as shown in FIG. 3, a hydrophilic resin or a water repellent resin is applied to the surface of the fin 12 to form a coating layer 18 having a predetermined thickness. In addition, as a method of forming the coating film layer 18 on the surface of the fin 12, a fin material (pre-coated fin material) on which a coating film has been formed in advance is processed into a predetermined fin shape and assembled to a heat transfer tube. After the pre-coating method for forming an and-tube heat exchanger, or a fin-and-tube heat exchanger by assembling fins and heat transfer tubes, the entire heat exchanger is transferred to a resin-dissolved tank There is a post-coating method in which a coating film is formed on the fin surface by an immersion method or the like. However, in the dipping method, it is difficult to paint a uniform coating film on the fin surface, and under the present situation where the gap between the fins is becoming narrower, in the dipping method, the resin dissolved between the fins is difficult to spread, Since it may be difficult in practice, a precoat method with excellent quality is preferably employed.

  On the other hand, as is well known, the round tubular heat transfer tube 14 is made of a metal material made of copper, copper alloy, aluminum, aluminum alloy, or the like, and is a smooth tube having a circular cross section here. According to the present invention, an adhesive resin that is softened or melted by heating to 100 ° C. to 200 ° C. is applied to the outer surface to form an adhesive coating layer 22 having a predetermined thickness ( (See FIG. 3). The adhesive resin referred to here is a state in which the metal material constituting the fin 12 and the metal material constituting the heat transfer tube 14 are interposed, and both the metal materials are physically or mechanically fixed. It means a resin that can be maintained. Further, the thickness of the coating layer 22 is appropriately determined according to the clearance determined by the outer diameter of the heat transfer tube 14 and the inner diameter of the assembly hole 16 formed in the fin 12, the tube expansion rate, and the like. However, it is preferably about 1 to 10 μm.

  In addition, as one of the adhesive resins that form such a coating layer 22, an adhesive resin that softens or melts when heated to 100 ° C. to 200 ° C., for example, an acrylic resin type, a polyurethane resin type, etc. , Vinyl acetate resin, epoxy resin, vinyl chloride resin, melamine resin, phenol resin, polyolefin resin, polystyrene resin, polyvinyl alcohol resin, etc. And will be used. Among them, in particular, a hot melt adhesive resin having a melting point of 100 ° C. to 200 ° C. is advantageously used. Further, as the adhesive resin for forming the coating layer 22, a heat-reactive adhesive resin having a reaction temperature of 100 ° C. or higher and 200 ° C. or lower can also be used. The heat-reactive adhesive resin referred to here means that the chemical reaction or polymerization reaction of the contained substance occurs by maintaining the temperature at a temperature higher than the reaction temperature, the resin is cured, and the adhesiveness is improved. This includes a resin having such a characteristic that includes, for example, a thermosetting resin, a reactive resin, a reactive adhesive, and the like. As such a heat-reactive adhesive resin, specifically, epoxy, cyanoacrylate, polyurethane, acrylic, or a combination of them or a thermoplastic resin Are appropriately selected and used.

  Moreover, it is desirable to use a highly flexible resin among such adhesive resins. Even when the heat exchanger is deformed by performing processing such as L bending after assembling the fins 12 and the heat transfer tubes 14 to form a heat exchanger by using a highly flexible resin. The effect of reducing the contact thermal resistance between the fin 12 and the heat transfer tube 14 by effectively maintaining the adhesion between the heat transfer tube 14 and the fin 12 can be exhibited.

  Then, using such heat transfer tubes 14 and fins 12, a plurality of such fins 12 are parallel to each other and spaced apart from each other in a state where the assembly holes 16 formed in each of them are aligned. Since the heat transfer tube 14 is inserted into the aligned assembly hole 16 and then assembled by the tube expansion method, the target heat transfer tube for the fin-and-tube heat exchanger is configured. is there. At this time, the gap between the outer surface (outer peripheral surface) of the heat transfer tube 14 and the inner surface of the assembly hole 16 of the fin 12 is a coating formed on the outer peripheral surface of the heat transfer tube 14 as shown in FIG. The film layer 22 is microscopically filled with an adhesive resin, and is fixed to constitute an integral fin-and-tube heat exchanger heat transfer tube. And each end part of the heat exchanger tube 14 which comprises such a heat exchanger tube for fin and tube type | mold heat exchangers will braze a U-bend pipe | tube to the heat exchanger tube edge part on the opposite side to the side which gave the hairpin bending process. Through the process of attaching, etc., it is configured as a fin-and-tube heat exchanger 10 assembled integrally as shown in FIG.

  Therefore, according to the fin-and-tube heat exchanger 10 configured in accordance with the present invention, the set of fins 12 is formed by the coating layer 22 made of an adhesive resin formed on the outer surface of the heat transfer tube 14. Since the gap between the inner surface of the attachment hole 16 and the outer surface of the heat transfer tube 14 is filled, and the fin 12 is fixed to the heat transfer tube 14, the contact thermal resistance between the fin 12 and the heat transfer tube 14. Thus, the heat exchange performance of the heat exchanger 10 can be advantageously improved.

  Further, since the temperature at which the adhesive resin constituting the coating layer 22 formed on the outer surface of the heat transfer tube 14 is softened or melted is 100 ° C. or higher, the heat generated when the heat exchanger 10 is operated. Therefore, it is possible to advantageously avoid the possibility that the coating layer 22 is melted or washed away. That is, in the fin-and-tube heat exchanger, when operated as an evaporator of an air conditioner, the temperature of the refrigerant circulating in the heat transfer tube 14 may be close to 100 ° C. When the softening temperature or melting temperature of the adhesive resin forming the film layer 22 is less than 100 ° C., the adhesive resin filling the gaps between the fins 12 and the heat transfer tubes 14 is melted and washed away during the operation of the air conditioner. There is a problem that a continuous contact thermal resistance reduction effect cannot be obtained.

  Further, since the melting point of the adhesive resin forming the coating layer 22 is 200 ° C. or less, the functions of the hydrophilic coating and the water-repellent coating formed on the surface of the fin 12 are improved. The heat transfer tubes 14 and the fins 12 can be assembled and held together while being kept, so that the fin-and-tube heat exchanger 10 can be formed. That is, after the heat transfer tube 14 is inserted into the assembly hole 16 provided in the fin 12 made of aluminum or aluminum alloy having a hydrophilic resin or water repellent resin applied on its surface, the tube is heated and then heated. Then, the adhesive resin forming the coating layer 22 applied to the outer surface of the heat transfer tube 14 is liquefied or softened, and the gap between the inner surface (collar portion 20) of the assembly hole 16 and the outer surface of the heat transfer tube 14 is obtained. Since the temperature at which the adhesive resin is filled can be suppressed to 200 ° C. or lower, which is lower than the temperature at which the hydrophilic coating film or water-repellent coating film precoated on the surface of the fin 12 causes thermal decomposition, etc. The fear of causing a decrease in performance of the hydrophilic coating film or the water-repellent coating film can be effectively avoided. In consideration of further maintaining the functions of the hydrophilic coating film or the water-repellent coating film, the upper limit of the melting point of the adhesive resin constituting the coating film layer 22 is preferably 150 ° C. or lower.

  And since the effect of the hydrophilic coating film and water-repellent coating film formed on the surface of the fin 12 is thus satisfactorily exhibited, dew condensation water generated on the surface of the fin 12 when the heat exchanger 10 is operated. Can be discharged smoothly from the surface of the fins 12 by these coating films, and the increase in ventilation resistance due to the condensed water can be effectively suppressed, so that the heat exchanger 10 has a stable and high heat exchange performance. Can be maintained.

  By the way, the fin-and-tube heat exchanger 10 having such a configuration is advantageously manufactured by adopting the following method. That is, first, an adhesive resin having a melting point of 100 ° C. or higher and 200 ° C. or lower or a thermal reaction having a reaction temperature of 100 ° C. or higher and 200 ° C. or lower is applied to the outer surface of a smooth tube formed of copper or a copper alloy, or aluminum or an alloy thereof. After applying the mold adhesive resin, if the adhesive resin is a hot-melt adhesive resin, hold it at a temperature lower than its melting point, and if it is a heat-reactive adhesive resin, hold it at a temperature lower than its reaction temperature for adhesion. The conductive resin is dried and solidified (in the case of a heat-reactive adhesive resin), and a coating layer 22 having a predetermined thickness is formed on the outer surface of the heat transfer tube 14.

  On the other hand, by applying a hydrophilic coating or a water-repellent coating to the surface of the aluminum plate or aluminum alloy plate on which a coating layer having a predetermined thickness is formed, a circular cross-sectional shape is obtained. A fin 12 having a predetermined shape in which an assembly hole 16 is formed is prepared. Then, a plurality of such fins 12 are arranged in parallel to each other at a predetermined interval so that the respective assembly holes 16 coincide with each other, and sequentially pass through the assembly holes 16 of the plurality of fins 12. As described above, the previously prepared heat transfer tube 14 is inserted. Then, the heat transfer tube 14 is expanded at a predetermined expansion rate by a known mechanical tube expansion method or hydraulic tube expansion method, and fixed to the assembly holes 16 of the fins 12 to produce an assembly. At this time, a microscopic gap exists between the inner surface of the assembly hole 16 of the fin 12 and the outer surface of the heat transfer tube 14.

  Next, the assembly is held in a temperature that is not lower than the melting point of the adhesive resin applied to the outer surface of the heat transfer tube 14 and not higher than 200 ° C., thereby melting the adhesive resin and making it flowable. The adhesive resin thus melted is caused to flow and fill the entire gap existing between the inner surface of the assembly hole 16 of the fin 12 and the outer surface of the heat transfer tube 14. Thereafter, the assembly in which the gaps are filled with the adhesive resin is cooled in the case of a hot-melt adhesive resin, and is maintained at a temperature not lower than the room temperature and not higher than the melting point of the adhesive resin. Further, in the case of a heat-reactive adhesive resin, the adhesive resin is solidified by holding and reacting as it is, and a fin and an integrated fin 12 and heat transfer tube 14 as shown in FIG.・ The tube heat exchanger is completed.

  By adopting such a manufacturing method, the heat transfer tube 14 and the fin 12 can be assembled and fixed at a low temperature, so that the hydrophilic coating or water repellent coating formed on the surface of the fin 12 can be used. The fin-and-tube heat exchanger 10 in which the function of the membrane is maintained well can be advantageously manufactured.

  Moreover, in this manufacturing method, since the fin by which the hydrophilic coating material and the water-repellent coating material were apply | coated previously on the surface is used, the coating film formed in a fin can be made high quality. Furthermore, since it is not necessary to form a hydrophilic paint or water-repellent paint film on the fin surface after assembling the fin and the heat transfer tube, the manufacturing cost of the heat exchanger can be advantageously reduced and the fin spacing can be reduced. As a result, it is possible to reduce the size of the heat exchanger and to improve the heat exchange performance.

  As mentioned above, one of the representative embodiments of the present invention and the manufacturing method thereof have been described in detail. However, these are merely examples, and the present invention is specific to such embodiments. It should be understood that the description is not to be construed as limiting in any way.

  For example, a lubricant, a thixotropic agent, an antioxidant, a storage stabilizer, an antistatic agent, and the like may be blended in the adhesive resin that forms the coating layer 22 applied to the outer surface of the heat transfer tube 14. . Moreover, the adhesive coating film which gives this coating film layer 22 may couple | bond with active functional groups, such as a hydroxyl group which remain | survives in the hydrophilic coating film apply | coated to the surface of the fin 12. FIG. By setting it as such an adhesive coating film, the coupling | bonding with the coating film of the fin 12 surface can be improved, and it is possible to reduce effectively the contact thermal resistance between the fin 12 and the heat exchanger tube 14. Become.

Furthermore, the adhesive resin that forms the coating layer 22 may contain a particulate inorganic material having good thermal conductivity that does not impair fluidity. This is because, since a resin containing an adhesive component usually has poor thermal conductivity, filling the gap between the fin and the heat transfer tube with a resin containing the adhesive component has air in the gap. Although the thermal conductivity is better than in the case, it does not exhibit sufficient thermal conductivity. Therefore, it is possible to further improve the thermal conductivity by mixing a material having good thermal conductivity into the adhesive resin. Examples of the inorganic material mixed in the adhesive resin include fine nickel, silica (SiO ₂ ), alumina (Al ₂ O ₃ ), carbon, and the like. However, if too much inorganic material is mixed, when the adhesive resin is heated, the melted adhesive resin will not flow sufficiently, and it will conform to the gap formed between the fin and the heat transfer tube. (To be filled) will be insufficient. Moreover, when using a metal material, it is desirable that the natural potential is nobler than the fin, and in this case, preferential corrosion of the bonded portion can be prevented.

  Moreover, you may mix | blend a hardening | curing agent with adhesive resin. It does not restrict | limit especially as a hardening | curing agent mix | blended here, It can use combining 1 type (s) or 2 or more types, such as block isocyanate, a phenol resin, and an amino resin. For example, by blending two or more curing agents having different reaction temperatures, the curing rate during heating can be adjusted, and dripping of the adhesive layer due to gravity can be prevented. Moreover, such a hardening | curing agent can also be mix | blended in the state contained in the microcapsule with a particle size of 1-1000 micrometers which used gelatin, gum arabic, urethane resin, etc. for the film agent. When blended in this way, curing of the resin other than the joint where pressure is applied is suppressed, and the heat exchanger after bonding can be easily bent. Furthermore, an anaerobic curing agent combining acrylic acid-based diester and N, N-dimethylaniline or the like can be blended, and in this case, only the portion where oxygen is blocked by close contact during assembly may be cured. Therefore, the heat exchanger after bonding can be easily bent. Furthermore, a humidity curing agent can also be blended, and in this case, it is possible to further increase the strength at the time of a submerged airtight test after assembling the heat exchanger or during an evaporation operation.

  Furthermore, the adhesive resin may be one or more of organic fine particles such as PTFE and polyethylene, or low melting point metal fine particles having a melting point of 200 ° C. or less such as Sn—Bi type and Sn—Ag—Cu—Bi type. May be blended. By blending such organic fine particles and metal fine particles, it becomes possible to improve the slipperiness when the heat transfer tube 14 is inserted into the assembly holes 16 of the fins 12, and the productivity of the heat exchanger 10 is effectively improved. Can be increased. In addition, when such low melting point metal fine particles are blended, the low melting point metal is melted and integrated during heating, whereby the contact thermal resistance can be further reduced. Also, in this case, by simultaneously blending flux components such as glutaric acid and adipic acid with the low melting point metal fine particles into the adhesive coating film, the oxide film of the low melting point metal particles can be removed during such heating. Thus, it is possible to further reduce the contact thermal resistance.

  In addition, it is also possible to mix | blend ER fluid which has magnetism with adhesive resin. By blending such an ER fluid, it is possible to effectively prevent or prevent the adhesive coating film softened during heating from dripping downward due to weight by applying a magnetic force from above during heating. It becomes possible to suppress.

  Furthermore, the coating layer 22 applied to the outer surface of the heat transfer tube 14 is not limited to the single coating layer shown in the above embodiment, and may be a plurality of two or more layers. For example, by forming a coating film layer with a resin having a low melting point and easily flowing in the top coat and forming a coating film layer with a resin having a small difference in linear expansion coefficient from the metal material in the undercoat, the adhesion area during heating can be reduced. The securing and the maintenance of the adhesion when using the heat exchanger can be advantageously made compatible.

  Such an adhesive resin can be applied to the outer surface of the fin 12. Thus, by applying the adhesive resin to both the outer surface of the heat transfer tube 14 and the outer surface of the fin 12, the gap between the heat transfer tube 14 and the fin 12 can be filled with the adhesive resin with higher accuracy. It becomes.

  Further, the coating film formed on the surface of the fin 12 can be formed of a single layer of hydrophilic resin or water-repellent resin coating film (coating layer 18) as in the above-described embodiment. However, a plurality of coating films may be formed on the surface of the fin substrate, and the outermost coating film of the plurality of coating films may be a coating film of hydrophilic resin or water repellent resin. For example, when forming a multi-layer coating film as such, first, on the surface of the aluminum plate, epoxy resin, urethane resin, polyester resin, acrylic resin, melamine resin, vinyl chloride resin, etc. It is preferable to form a coating film having corrosion resistance and comprising a coating film of a hydrophilic resin or a water-repellent resin as the outermost layer. By forming such a corrosion-resistant coating film, the corrosion resistance of the fins 12 made of an aluminum material can be advantageously improved.

  Furthermore, it is preferable that a film obtained by chemical film treatment (chemical conversion treatment) such as chromate treatment with phosphoric acid chromate or the like is formed on the surface of the fin 12 as a base treatment layer. That is, an aluminum plate (substrate) and a hydrophilic resin coating film formed on the surface thereof by forming such a base treatment layer on the surface of the fin substrate made of aluminum or aluminum alloy forming the fins 12. In addition, it is possible to effectively improve the adhesion to water-repellent resin coatings and corrosion-resistant coatings.

  In the above-described embodiment, a smooth tube having no groove or the like on the inner surface is used as the heat transfer tube 14. However, as shown in FIG. 4, a large number of grooves 32 are formed on the inner surface. Of course, a so-called inner surface grooved heat transfer tube 30 can be employed. By adopting such an internally grooved heat transfer tube 30, it is possible to advantageously improve the heat transfer coefficient in the tube of the heat transfer tube 14 (30), thereby effectively improving the heat exchange performance of the heat exchanger 10. It is possible to increase it.

  Further, examples of the heat transfer tube 14 include a round tubular smooth tube whose cross section perpendicular to the tube axis has a circular shape and the above-described internally grooved heat transfer tube. Various known heat transfer tubes can be used as long as they can be fixed by the tube expansion method. For example, it is possible to adopt a flat tube with a single hole having a flat cross section, a flat multi-hole tube with a plurality of holes extending in the tube axis direction, and the like.

  In addition, a lubricating layer such as carnauba wax, polyethylene wax, lubricating oil, polyethylene glycol, or the like is formed on the outer surface of the heat transfer tube 14 (the outer surface of the coating layer 22 formed on the outer surface of the heat transfer tube 14). It is also possible. By forming such a lubricating layer, it is possible to improve the slipperiness when inserting the heat transfer tube into the fin assembly hole, and thus it is possible to improve the productivity of the heat exchanger. Become.

  Moreover, in said embodiment, it is set as the fin and tube type heat exchanger 10 with which a heat exchanger is comprised so that the several heat exchanger tube 14 may penetrate with respect to the fin 12 of 1 sheet. However, as shown in FIG. 5, a so-called serpentine heat exchanger 40 having a divided fin type, that is, a configuration in which one heat transfer tube 44 is arranged through one fin 42 is arranged. Good. Even in the heat exchanger 40 of such a form, the contact heat resistance between the fin and the heat transfer tube of the heat transfer tube for the fin-and-tube heat exchanger according to the present invention is effectively reduced, and the heat exchange performance. The effect of improving is advantageously exhibited.

  In addition, although not listed one by one, the present invention is implemented in a mode to which various changes, modifications, improvements and the like are added based on the knowledge of those skilled in the art. It goes without saying that any one of them falls within the scope of the present invention without departing from the spirit of the invention.

  Hereinafter, one representative embodiment of the present invention will be shown to clarify the present invention more specifically. However, the present invention is not limited by the description of such embodiment. It goes without saying that it is not something to receive.

  First, in order to construct a fin-and-tube heat exchanger according to the present invention, an aluminum alloy (JIS A3003) is extruded as a heat transfer tube (14) to obtain a cross section as shown in FIG. Prepared a heat transfer tube with an inner surface groove having an outer diameter of 7.0 mm. Such an internally grooved heat transfer tube has a bottom wall thickness of 0.47 mm, fin height: 0.18 mm, number of grooves: 54, fin apex angle: 20 °, lead angle: 0 ° It has the original. Then, an acrylic resin adhesive (KONISHI, KV610) with 30 to 40% toluene and 30 to 40% ethyl acetate as a solvent (paint) is prepared and impregnated with felt. At room temperature, the surface of the heat transfer tube (14) prepared in advance is brought into contact with the outer peripheral surface of the heat transfer tube (14), and the coating made of an adhesive resin having a uniform film thickness of 10 μm and good adhesion. A film was formed.

  On the other hand, as an aluminum fin material for forming the fins (12), a plate material made of pure aluminum (JIS A1050) having a plate thickness of 0.1 mm was prepared. And the surface treatment which consists of three layers as shown in FIG. 6 was given with respect to the surface of this aluminum fin material. That is, first, a chemical conversion film (52) made of phosphate chromate was formed on the surface of the aluminum fin material (50) by subjecting the aluminum fin material (50) to a phosphate chromate immersion treatment. Next, an epoxy resin was applied onto the chemical conversion film (52) using a roll coater and heated at a temperature of 220 ° C. for 10 seconds to form a corrosion-resistant coating film (54) having a thickness of 1 μm. . Further, after cooling with air and applying a coating film for hydrophilic coating film made of polyvinyl alcohol resin on the surface of the corrosion-resistant coating film (54) and heating at a temperature of 220 ° C. for 10 seconds, the film thickness: 1. A 5 μm hydrophilic coating (56) was formed to obtain a hydrophilic / corrosion resistant aluminum fin material. In addition, the hydrophilic coating film (56) made of polyvinyl alcohol resin undergoes thermal decomposition at a temperature of 170 ° C. or higher and causes a decrease in performance as a hydrophilic coating film.

  Next, the hydrophilic / corrosion-resistant aluminum fin material thus obtained is subjected to a known press process or the like, whereby an assembly hole (16) through which the heat transfer tube (14) is inserted as shown in FIG. A fin (12) having a rectangular fin shape with a vertical length of 300 mm and a horizontal length of 25.4 mm was formed. A fin collar (20) standing up with a predetermined height from the periphery of the hole was integrally formed in the assembly hole (16) portion of the fin (12). Further, the inner diameter of the collar portion (20) was set to 7.2 mm.

  Then, using the heat transfer tubes (14) and fins (12) obtained as described above, the heat transfer tubes as shown in FIG. 7 are arranged in two rows and 14 stages, 300 mm × 300 mm × 25. A 4 mm fin-and-tube heat exchanger (10) was produced. The heat transfer tube and the fin are fixed in accordance with the present invention by applying an adhesive resin on the outer peripheral surface of the assembly hole (16) having an inner diameter of 7.2 mm in the fin (12). Insert a 7.0 mm heat transfer tube (14), expand the machine at a tube expansion rate of 6.0% and 2.6%, assemble and place in an oven, hold at 140 ° C. for 5 minutes, and bond By melting the resin containing the component, the resin containing the adhesive component was filled between the inner surface of the assembly hole (16) of the fin (12) and the outer surface of the heat transfer tube (14). Thereafter, the heat transfer tube (14) was fixed to the fin (12) by cooling to room temperature and solidifying the resin. The heat exchangers thus produced were referred to as Example 1 and Example 2, respectively.

On the other hand, although the same fins as those in Examples 1 and 2 are used as the fins, the heat transfer tubes are different from those in Examples 1 and 2, and use an internally grooved heat transfer tube whose adhesive resin is not applied to the outer surface. In the same manner as in Examples 1 and 2, a fin-and-tube heat exchanger was produced. Here, Comparative Example 1 was obtained by mechanical expansion at a pipe expansion rate of 6.0%, and Comparative Example 2 was obtained by mechanical expansion at a pipe expansion ratio of 2.6%. In any of the heat exchangers thereof Examples 1 and 2, the fin number: 214 sheets, the distance between the adjacent fins: a 1.4 mm, also the interval of heat transfer tubes shown in FIG. 8 (P ₁ , P ₂ ), the interval between the heat transfer tubes constituting one row: P ₁ is 21 mm, and the interval between the first and second heat transfer tubes: P ₂ is 12 mm.

  And about each heat exchanger produced in this way, the joining state of a fin and a heat exchanger tube was confirmed in the state after an assembly completion as a fin and tube type heat exchanger. As a result, in the heat exchangers of Example 1 and Example 2, the heat transfer tubes and the fins were firmly fixed with the adhesive resin, and the bonding state was good. On the other hand, in the heat exchanger of Comparative Example 2, since the tube expansion rate is 2.6%, which is due to the mechanical tube expansion with a low tube expansion rate, the heat transfer tubes and the fins are sufficiently fixed. The bonding state was not good.

  Moreover, in the produced heat exchanger, evaluation of the contact thermal resistance between the fin and the heat transfer tube was performed by the following method. That is, in each heat exchanger, hot water of 50 ° C. is flowed in the first row, and cold water of 20 ° C. is flowed in the second row so as to be an opposite flow, and the flow rates of hot water and cold water are changed. -The thermal resistance on the water side was subtracted by the plot method, and the thermal resistance was calculated and evaluated. The results are shown in Table 1 below. The test heat exchanger was installed in a vacuum vessel, and evaluation was performed while suppressing the influence of heat transfer by natural convection generated in the test part. In Table 1, the contact thermal resistance is shown as the contact thermal resistance ratio when the contact thermal resistance in the heat exchanger of Comparative Example 1 is 100. Further, the single tube performance and the heat exchange performance are also shown as performance ratios when the single tube performance and the heat exchange performance in Comparative Example 1 are set to 100, respectively.

  From the results of Table 1, it can be seen that the contact heat resistance ratio in the heat exchanger of Example 1 in which the adhesive coating film according to the present invention is formed is 51, and the contact heat resistance can be made very small. That is, the heat exchanger of Comparative Example 1 has a large pipe expansion rate of 6.0% as in the heat exchanger of Example 1, and the heat transfer pipe and the fins are firmly in contact when viewed macroscopically. Although it seems that there is a gap between the heat transfer tubes and the fins when viewed microscopically, the contact heat resistance is not sufficient, whereas in the heat exchanger of Example 1, It is confirmed that the contact thermal resistance is reduced by filling the microscopic gap between the heat transfer tube and the fin with the adhesive resin.

  Moreover, while the contact heat resistance ratio in the heat exchanger of Example 2 is 128, the contact heat resistance ratio in the heat exchanger of Comparative Example 2 is 147, which is 87% of Comparative Example 2 having the same tube expansion rate. It was confirmed that the contact thermal resistance was obtained. In either heat exchanger, the tube expansion rate is as low as 2.6%, and the contact between the heat transfer tube and the fin is not good, but in the heat exchanger of Example 2, the heat transfer tube and It was confirmed that the contact thermal resistance is reduced by filling the gaps between the fins with the adhesive resin and exhibits excellent characteristics.

Furthermore, in the heat exchanger of Example 1, the inner diameter of the assembly hole: D ₂ = 7.2 mm, whereas the outer diameter of the heat transfer tube after the expansion: D ₁ = 7.0 × 1.06 = 7. Since it is 42 mm, D ₁ −D ₂ = 7.42−7.2 = 0.22 mm, whereas in the heat exchanger of Example 2, the inner diameter of the assembly hole: D ₂ = 7.2 mm On the other hand, since the outer diameter of the heat transfer tube after the expansion is D ₁ = 7.0 × 1.026 = 7.182 mm, D ₁ −D ₂ = 7.182−7.2 = −0.018 mm It has become. Thus, it is confirmed that the heat exchanger of Example 1 that satisfies the relationship of D ₁ -D ₂ ≧ 0.08 mm can more effectively achieve a reduction in contact thermal resistance. It is.

  In addition, in the heat exchanger of Example 1, since the expansion rate of mechanical expansion is as large as 6.0% and the inner fins of the heat transfer tube are crushed significantly, compared to the heat exchanger of Example 2, Although the heat transfer performance was as low as 20%, the contact heat resistance between the fins and the heat transfer tubes was low, so the heat exchange performance of the entire heat exchanger was higher than that of the heat exchanger of Example 2. The result is 1% higher.

  Next, phosphorous deoxidized copper (JIS C1220) is used as the heat transfer tube (14), and the cross section has a circular shape as shown in FIG. 4 by a known rolling method. A 0 mm internally grooved heat transfer tube was prepared. Such an internally grooved heat transfer tube has dimensions such as bottom wall thickness: 0.23 mm, fin height: 0.18 mm, number of grooves: 54, fin apex angle: 20 °, lead angle: 27 °. It has the original. Then, a 20% aqueous solution of polyvinyl alcohol having an average degree of polymerization of 600 and a degree of saponification of 88% and a 40% aqueous solution of blocked isocyanate in a ratio of 1: 9 (paint) is prepared, and this is used as a felt. After impregnation and contact with the surface of the heat transfer tube (14) at room temperature, the coating was held at 100 ° C. for 15 minutes, and the film thickness: 10 μm was formed on the outer peripheral surface of the heat transfer tube (14). A coating film made of an adhesive resin that was uniform and had good adhesion was formed. The paint has a reaction temperature of 140 ° C. and softens at 120 ° C., which is lower than the reaction temperature.

  On the other hand, a plate material made of pure aluminum (JIS A1050) having a plate thickness of 0.1 mm was prepared as an aluminum fin material for forming the fin (12). And the surface treatment which consists of three layers as shown in FIG. 6 was given with respect to the surface of this aluminum fin material. That is, first, a chemical conversion film (52) made of phosphate chromate was formed on the surface of the aluminum fin material (50) by subjecting the aluminum fin material (50) to a phosphate chromate immersion treatment. Next, an epoxy resin was applied onto the chemical conversion film (52) using a roll coater and heated at a temperature of 220 ° C. for 10 seconds to form a corrosion-resistant coating film (54) having a thickness of 1 μm. . Further, after cooling with air and applying a coating film for hydrophilic coating film made of polyvinyl alcohol resin on the surface of the corrosion-resistant coating film (54) and heating at a temperature of 220 ° C. for 10 seconds, the film thickness: 1. A 5 μm hydrophilic coating (56) was formed to obtain a hydrophilic / corrosion resistant aluminum fin material. In addition, the hydrophilic coating film (56) made of polyvinyl alcohol resin undergoes thermal decomposition at a temperature of 170 ° C. or higher and causes a decrease in performance as a hydrophilic coating film.

  Next, the hydrophilic / corrosion-resistant aluminum fin material thus obtained is subjected to a known press process or the like, whereby the assembly hole (16) through which the heat transfer tube (14) is inserted as shown in FIG. A fin (12) having a rectangular fin shape with a vertical length of 300 mm and a horizontal length of 25.4 mm was formed. A fin collar (20) standing up with a predetermined height from the periphery of the hole was integrally formed in the assembly hole (16) portion of the fin (12). Further, the inner diameter of the collar portion (20) was set to 7.2 mm.

  Then, using the heat transfer tubes (14) and fins (12) obtained as described above, the heat transfer tubes as shown in FIG. 7 are arranged in two rows and 14 stages, 300 mm × 300 mm × 25. A 4 mm fin-and-tube heat exchanger (10) was produced. The heat transfer tube and the fin are fixed in accordance with the present invention by applying an adhesive resin on the outer peripheral surface of the assembly hole (16) having an inner diameter of 7.2 mm in the fin (12). After inserting a 7.0 mm heat transfer tube (14), mechanically expanding the tube at a tube expansion rate of 6.0%, and assembling, the assembly is placed in an oven and held at 150 ° C. for 15 minutes, By melting a coating film made of an adhesive resin applied to the outer surface of the heat transfer tube (14), the adhesive resin is used as an inner surface of the assembly hole (16) of the fin (12) and the heat transfer tube (14). The gap between the outer surface and the outer surface was filled, and the adhesive resin was reacted and cured to fix the heat transfer tube (14) to the fin (12). The heat exchanger produced in this manner was referred to as Example 3.

On the other hand, although the same fin as that in Example 3 is used as the fin, the heat transfer tube is different from Example 3 in that the inner surface grooved heat transfer tube on which the adhesive resin is not applied is used. In the same manner as in No. 3, a fin-and-tube heat exchanger was produced and used as Comparative Example 3. Here, the expansion ratio of the mechanical expansion was 6.0% as in the case of Example 3. In any of the heat exchangers of Example 3 and Comparative Example 3, the number of fins: 214, the fin interval : 1.4 mm, and with respect to the intervals (P ₁ , P ₂ ) of the heat transfer tubes shown in FIG. 8, the interval between the heat transfer tubes constituting one row: P ₁ is 21 mm, The interval between the heat transfer tubes in the row: P ₂ was set to 12 mm.

  And about each heat exchanger produced in this way, the joining state of a fin and a heat exchanger tube was confirmed in the state after an assembly completion as a fin and tube type heat exchanger. As a result, the joining state of both the heat exchangers of Example 3 and Comparative Example 3 was good. In particular, in the heat exchanger of Example 3, the heat transfer tube and the fin are fixed by mechanical tube expansion with a high tube expansion rate of 6.0%, and an adhesive is interposed between the heat transfer tube and the fin. Therefore, the bonding state was strong.

  Further, in the heat exchangers of Example 3 and Comparative Example 3 manufactured as described above, the contact heat resistance between the fins and the heat transfer tubes was determined in the same manner as the heat exchangers of Examples 1 and 2. Evaluation was performed. As a result, when the contact thermal resistance of Comparative Example 3 was set to 100, the contact thermal resistance ratio of Example 3 was 50. From this, it was confirmed that the contact heat resistance is reduced and the heat exchange performance can be improved by filling the gap between the heat transfer tube and the fin with the adhesive resin.

DESCRIPTION OF SYMBOLS 10 Heat exchanger 12 Fin 14 Heat exchanger tube 16 Assembly hole 18 Coating layer 20 Color part 22 Coating layer

Claims (3)

A heat transfer tube for a fin-and-tube heat exchanger that is inserted into an assembly hole provided in a fin made of aluminum or an alloy thereof made by applying a hydrophilic paint or a water-repellent paint to the surface and assembled by expansion. And
An adhesive coating film made of a heat-reactive adhesive resin having a reaction temperature of 100 ° C. to 200 ° C. is formed on the outer surface, and the reaction temperature of the adhesive resin is higher than that of the adhesive resin when assembled to the fin. The adhesive resin is softened by being held at a temperature of 200 ° C. or lower, and the adhesive resin is filled with the adhesive coating while filling the gap between the inner surfaces of the assembly holes of the fins. A heat transfer tube for a fin-and-tube heat exchanger, wherein the heat-transfer tube is structured such that it can be reacted and cured to be fixed to the fin. Fin-and-tube heat exchange by inserting a heat transfer tube into an assembly hole provided in a fin made of aluminum or its alloy with a hydrophilic or water-repellent coating applied to the surface, and assembling by expansion Make a container
As the heat transfer tube, using a heat transfer tube of claim 1, by maintaining the reaction temperature above 200 ° C. below the temperature of the thermal reaction type adhesive resin, which is formed on the outer surface of such heat transfer tube heat and allowed to soften the adhesive coating film consisting of reactive adhesive resin, the adhesive coating film, while filling the gap between the assembled inner pore surface of the fin, the adhesive resin reaction, is cured, A fin-and-tube heat exchanger, wherein the heat transfer tube is fixed to the fin. After applying a heat-reactive adhesive resin having a reaction temperature of 100 ° C. or more and 200 ° C. or less to the outer surface of the heat transfer tube, the adhesive resin is dried by maintaining the temperature below the reaction temperature of the adhesive resin. By preparing a heat transfer tube formed with an adhesive coating film,
After the heat transfer tube is inserted into an assembly hole provided in a fin made of aluminum or aluminum alloy formed by applying a hydrophilic paint or a water repellent paint on the surface, the heat transfer pipe is expanded, and an assembly is obtained. A step of producing
The assembly is held at a temperature not lower than the reaction temperature of the adhesive resin that constitutes the adhesive coating film and not higher than 200 ° C. to soften the adhesive resin and transfer to the inner surface of the fin assembly hole. Filling with the outer surface of the heat tube and reacting and curing the adhesive resin to complete an integrated fin-and-tube heat exchanger;
A method for manufacturing a fin-and-tube heat exchanger.

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