JP2006125658A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a large-size heat exchanger of high reliability to the leakage of refrigerant, used in a cooling device applying a flammable refrigerant. <P>SOLUTION: In this heat exchanger in which the refrigerant is circulated, one heat exchanger 1 is constituted by connecting a plurality of fin tube assemblies 4 formed by inserting and fixing heat transfer tubes 2 to flat fins 3 stacked at intervals to each other, by joint pipes 5, thus the heat exchanger 1 of large size and high reliability to the leakage of refrigerant can be provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat exchanger used in a refrigeration cycle using a combustible refrigerant.

  In recent years, from the viewpoint of protecting the earth's ozone layer, chlorine atoms such as refrigerant CFC (chlorofluorocarbon) -12 or HCFC (hydrochlorofluorocarbon) -22, which have been used in refrigeration cycles of cooling devices in vending machines and refrigerators, etc. Use of the contained refrigerant is regulated, and conversion to an HFC (hydrofluorocarbon) refrigerant that does not contain chlorine atoms and does not destroy the ozone layer is in progress.

  Conventionally, in vending machines that mainly used HCFC-22 refrigerant, R-407C, which is a mixed refrigerant of HFC refrigerant, is used as an alternative refrigerant, and in refrigerators that use CFC-12 refrigerant, the alternative refrigerant. HFC134a is adopted.

  On the other hand, these HFC refrigerants such as R-407C do not destroy the ozone layer, but because of their high global warming potential, they are inadequate for global warming, and as a refrigerant with a low global warming potential, HC (hydrocarbon) refrigerant is used instead of HFC refrigerant.

  HC (hydrocarbon) refrigerant is a flammable refrigerant. From the viewpoint of preventing explosion accidents at the time of leakage, etc., it is important to reduce the number of welded parts of heat exchangers used in refrigeration and air-conditioning equipment and to reduce the amount of enclosed refrigerant. It has become. In addition, from the viewpoint of effective use of earth resources and power consumption suppression, there is a demand for more efficient heat exchangers used in refrigeration and air conditioning equipment.

  As a heat exchanger used in a refrigeration cycle using a combustible refrigerant, there is a heat exchanger using a serpentine tube obtained by continuously bending a single pipe.

  FIG. 7 is a perspective view of a conventional heat exchanger described in Patent Document 1. FIG.

  As shown in FIG. 7, the heat exchanger 1 includes a heat transfer tube 2 in which a combustible refrigerant flows and a flat fin 3 that is stacked while being spaced apart from each other and to which the heat transfer tube 2 is inserted and fixed. The heat transfer tube 2 is a serpentine tube obtained by continuously bending a single pipe. The air flowing through the gap between the refrigerant flowing in the heat transfer tube 2 and the flat fin 3 exchanges heat through the heat transfer tube 2 and the flat fin 3.

  By making the heat transfer tube 2 into a serpentine tube in which one pipe is continuously meandered and bent, the welded portion can be greatly reduced.

  FIG. 8 is a front view of another conventional heat exchanger described in Patent Document 2. FIG.

As shown in FIG. 8, the heat exchanger 1 has a refrigerant path formed by welding a hairpin 8 and a return bend 9, and the flat fin 3 is in close contact with the hairpin 8. Compared to the heat exchanger described in Patent Document 1, the number of welds is increased, so there are few examples of use in a cooling system using a flammable refrigerant, and many are used for HFC refrigerant, HCFC refrigerant, and the like.
Japanese Patent No. 2555453 Japanese Patent No. 3198168

  However, since the conventional heat exchanger described in Patent Document 1 is a serpentine tube in which a heat transfer tube is meandering and bending a single continuous pipe, the total length per pipe is long and before the bending process is performed. It is necessary to secure a large space in the factory for storing the pipe in the straight state for a temporary period until the bending process. The total length of heat exchanger pipes currently used in refrigerators and vending machines that use flammable refrigerant is about 10 m at the maximum, but for cooling devices that require a larger heat exchanger (for example, industrial equipment) Assuming that a flammable refrigerant is used, the total length of the pipe constituting the heat transfer tube of the conventional heat exchanger described in Patent Document 1 reaches several tens of meters. It was difficult to secure a space for storing pipes with a total length of several tens of meters in the factory, and a large loss was generated from the viewpoint of the manufacturing process, which had the problem that manufacturing was difficult.

  The present invention solves the above-described conventional problems, and includes a heat transfer tube configured by bending a refrigerant flow path of a heat exchanger in a meandering manner so that at least one has two or more bent portions. The total length per pipe can be shortened by configuring the joint pipe connecting the heat transfer tube ends to each other, and the large and HFC described in Patent Document 2 in the same manufacturing space as before. By welding a hairpin and a return bend used in a cooling device using a refrigerant or an HCFC refrigerant, a heat exchanger with higher reliability against refrigerant leakage can be provided as compared with a heat exchanger that constitutes a refrigerant path.

  In order to solve the above-described conventional problems, the heat exchanger of the present invention includes a fin tube assembly in which a heat transfer tube in which a combustible refrigerant flows is inserted and fixed to flat fins stacked while being spaced apart from each other. And at least two of the fin tube assemblies are joint pipes connecting the end portions of the heat transfer tubes, and at least one of the heat transfer tubes is bent in a meandering manner so as to have two or more bent portions. It is configured.

  This shortens the overall length per heat transfer tube compared to a serpentine tube in which one continuous pipe is serpentine bent, so that the pipe in a straight state before bending is bent. The heat that constitutes the refrigerant path by welding the hairpin and return bend, which is large and used for the cooling device using HFC refrigerant or HCFC refrigerant, can be reduced for the temporary storage until the process. Compared to the exchanger, it is possible to provide a highly reliable heat exchanger against refrigerant leakage.

  The present invention is a large-sized heat exchanger that is more reliable for refrigerant leakage than a heat exchanger that forms a refrigerant path by welding a hairpin and a return bend used in a cooling device using HFC refrigerant or HCFC refrigerant. Can be provided.

  According to the first aspect of the present invention, there is provided a fin tube assembly in which a heat transfer tube in which a combustible refrigerant flows is inserted and fixed to flat fins stacked while being spaced apart from each other, and at least two fin tubes. It is composed of a joint pipe that connects the heat transfer tube ends of the assembly, and at least one of the heat transfer tubes is formed by bending in a meandering manner so as to have two or more bent portions, and at least When two or more fin tube assemblies are connected to each other by a joint pipe to form one heat exchanger, and a refrigerant path is formed by a serpentine tube obtained by meandering a single continuous pipe. In comparison, the overall length per heat transfer tube is shortened. Therefore, in the manufacturing process, the space for storing the pipe in a straight state before bending can be temporarily reduced until the bending process. Because the number of welding points can be greatly reduced compared to the heat exchanger that constitutes the refrigerant path by welding the hairpin and return bend that are large and used in the cooling device using HFC refrigerant or HCFC refrigerant, A highly reliable heat exchanger against refrigerant leakage can be provided. For example, when compared with three rows and ten stages of heat exchangers, the number of welding locations can be significantly reduced from 30 to 6 locations. Further, by connecting at least two or more fin tube assemblies with joint piping to form one heat exchanger, it is possible to arrange flat fins in the form of dividing the air flow direction. Thus, it is possible to ensure a high heat exchange capacity by the boundary layer leading edge effect. Further, it is possible to efficiently use flat fins, heat transfer tubes, or fin tube assemblies for a plurality of products, and the material cost can be reduced. In addition, it is possible to configure one heat exchanger from a plurality of fin tube assemblies having different intervals (fin pitches) for arranging flat fins, which is caused by clogging of flat fins such as clogging of dust and frost formation. Performance degradation can be partially avoided. In addition, in one heat exchanger, it is possible to configure the fin pitch of the portion with high air resistance to be sparse and the fin pitch of the low portion to be dense, so that the air resistance can be made uniform. , Heat exchange ability can be improved.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, the heat transfer tube is configured to be seamless for each row or each stage. By configuring the heat tubes so that there is no seam for each row or each step, the heat transfer tubes when the shape of the opening of the heat exchanger is the same (when the number of rows or steps and the fin length are the same) The material cost can be reduced by improving the efficiency of the parts. In addition, by configuring the heat transfer tubes to be seamless for each row or each stage, compared to the conventional case where the refrigerant path is configured with a serpentine tube obtained by meandering a single continuous pipe. The arrangement of the heat transfer tubes can be freely set. For this reason, it is possible to provide a heat exchanger having a specification capable of optimally arranging the heat transfer tubes in consideration of the shape of the opening and the heat exchange capability. Here, the row direction is a direction in which air passes through the heat exchanger body along the flat fin surface, and the step direction is a direction parallel to the flat fin and perpendicular to the row direction.

  The invention according to claim 3 is the invention according to claim 2, wherein the heat transfer tube is bent into a flat shape, and a refrigerant path portion is formed by a flat heat transfer tube and a joint pipe. Thus, the pipe twisting portion in the refrigerant path portion can be eliminated. Therefore, it is possible to eliminate the work hardening part by twisting the pipe constituting the refrigerant path part, improve the adhesion between the heat transfer tube and the fin by the hydraulic expansion pipe, etc., and improve the heat exchange capacity. Can do. In addition, since there is no twisting part in the heat transfer tube, the mechanical load due to twisting is not applied, and it is possible to reduce the wall thickness of the heat transfer tube compared to the case where twisting is performed, which reduces the material cost. Can be planned.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the flat fin has a fin collar. Thereby, the contact | adhesion power of a flat fin and a heat exchanger tube improves, heat exchange efficiency improves, and the enclosure amount of a combustible refrigerant | coolant can be reduced.

  The invention according to claim 5 is characterized in that, in the invention according to any one of claims 1 to 4, the refrigerant path is constituted by a plurality of paths, and the refrigerant path is constituted by a plurality of paths. By configuring, the amount of refrigerant flowing per heat transfer tube can be reduced, enabling efficient heat exchange, preventing drift of liquid refrigerant, reducing pressure loss in the tube, and improving heat exchange efficiency. The amount of flammable refrigerant enclosed can be reduced.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same reference numerals are given to the same configurations as those of the conventional example or the embodiments described above, and detailed descriptions thereof will be omitted. The present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a perspective view of a heat exchanger according to Embodiment 1 of the present invention. FIG. 2 is a perspective view of the fin tube assembly in the same embodiment. FIG. 3 is a perspective view of a heat transfer tube of the heat exchanger in the same embodiment. FIG. 4 is a perspective view of another example of the heat transfer tube of the heat exchanger according to the embodiment. FIG. 5 is a perspective view of a flat fin of the heat exchanger in the same embodiment.

  In FIG. 1, a heat exchanger 1 has a fin tube assembly as shown in FIG. 2, in which a heat transfer tube 2 in which a combustible refrigerant flows is inserted and fixed to flat fins 3 stacked while being spaced apart from each other. And at least one of the heat transfer tubes 2 is bent in a meandering manner so as to have two or more bent portions. It is configured.

  The combustible refrigerant flowing in the heat transfer tube 2 and air are heat-exchanged via the heat transfer tube 2 and the flat fins 3.

  About the heat exchanger comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  First, the heat transfer tube 2 obtained by bending a straight pipe into a meandering shape is inserted into the plate-like fin 3, and the heat transfer tube 2 and the plate-like fin 3 are tightly fixed by liquid pressure such as water or oil or other means. The fin tube assembly 4 is configured.

  This tube expansion step is omitted in some cases, and when the shape of the fin tube assembly 4 is maintained only by inserting the heat transfer tube 2 into the flat fin 3, or after the heat exchanger 1 is assembled, the tube expansion is performed. In some cases.

  Next, the heat exchanger 1 is configured by connecting the heat transfer tubes 2 of the fin tube assembly 4 with the joint pipe 5 by welding or the like. The connection means between the heat transfer pipe 2 and the joint pipe 5 is generally welded or brazed, but the optimum means varies depending on the material of both, so if the method can ensure the reliability against refrigerant leakage, the means is It doesn't matter.

  By adopting such a configuration, a heat exchanger having the same size as that of the conventional heat exchanger 1 compared to the case where the refrigerant path is formed by a serpentine tube obtained by meandering and bending a single continuous pipe. In comparison, the total length per single pipe can be shortened.

  As a result, it is possible to reduce the space for storing the pipe in a straight state before the meandering bending process, and the same manufacturing space is used for a cooling device that is larger than conventional and uses HFC refrigerant or HCFC refrigerant. By welding the hairpin and the return bend that are made, it is possible to provide a heat exchanger that is more reliable against refrigerant leakage than a heat exchanger that constitutes the refrigerant path.

  Further, a plurality of fin tube assemblies 4 as shown in FIG. 2, in which the heat transfer tubes 2 are inserted and fixed to the flat plate fins 3 that are stacked while being spaced apart from each other, are connected to each other by a joint pipe 5. By configuring the exchanger 1, it is possible to arrange the flat fins 3 in a divided form with respect to the air flow direction, and it is possible to ensure a high heat exchange capacity by the boundary layer leading edge effect. .

  Further, the flat fin 3, the heat transfer tube 2, or the fin tube assembly 4 can be efficiently used for a plurality of products, and the material cost can be reduced. Further, a plurality of fin tube assemblies having different arrangement intervals (fin pitches) of the plate-like fins 3 by connecting at least two fin tube assemblies 4 with joint pipes to form one heat exchanger. Four to one heat exchanger 1 can be configured, and performance degradation due to clogging of the flat fins 3 such as clogging of dust and frosting can be avoided. In addition, in one heat exchanger 1, it is possible to configure the fin pitch of the portion with high air resistance to be sparse and the fin pitch of the low portion to be dense so that the air resistance can be made uniform. And heat exchange capability can be improved.

  Further, as shown in FIG. 3, in the heat exchanger 1, the heat transfer tubes 2 are configured so as to be seamless for each row or each stage, so that the opening shape of the heat exchanger 1 is the same. In this case (when the number of rows or the number of stages and the fin portion length are the same), the heat transfer tube 2 can also be used, and the material cost can be reduced by increasing the efficiency of the parts. In addition, by configuring the heat transfer tubes 2 so as to be seamless for each row or each stage, compared to the case where the refrigerant path is configured by a serpentine tube obtained by meandering a single continuous pipe. Thus, the arrangement of the heat transfer tubes 2 can be freely set. For this reason, it is possible to provide the heat exchanger 1 having a specification capable of optimally arranging the heat transfer tubes 2 in consideration of the opening shape and the heat exchange capability.

  Moreover, as shown in FIG. 4, in the heat exchanger 1, the pipe twist process part in a refrigerant | coolant path | route part can be eliminated by bending the heat exchanger tube 2 in planar shape. Therefore, the work hardening part by twisting of the pipe constituting the refrigerant path part becomes zero, the adhesion between the heat transfer pipe 2 and the flat fin 3 by the hydraulic expansion pipe or the like can be improved, and the heat exchange capability is improved. Can be improved.

  Moreover, as shown in FIG. 5, in the heat exchanger 1, by providing the fin collar 6 in the flat fin 3, the adhesive force of the flat fin 3 and the heat exchanger tube 2 can be improved, and heat exchange capability is improved. Can be improved.

(Embodiment 2)
FIG. 6 is a perspective view of the heat exchanger according to Embodiment 2 of the present invention.

  In FIG. 6, the heat exchanger 1 has five refrigerant paths.

  About the heat exchanger comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  The heat exchanger 1 includes five refrigerant paths. In a conventional heat exchanger in which a refrigerant path is constituted by a serpentine tube obtained by meandering a single continuous pipe, the refrigerant path is a single continuous pipe. Is possible.

  The heat exchanger 1 includes a plurality of refrigerant paths, thereby reducing the amount of refrigerant flowing per heat transfer tube, promoting efficient heat exchange, preventing liquid refrigerant drift, and reducing the pressure loss in the pipe. Reduction is possible, heat exchange efficiency is improved, the amount of refrigerant filling can be reduced, and the risk of ignition due to refrigerant leakage when a combustible refrigerant is used as the refrigerant can be reduced.

  As a means for configuring the refrigerant path by a plurality of paths, the ends of the heat transfer tubes 2 are generally connected to each other by using a flow divider 7 as shown in FIG. Any means can be used as long as it can be divided.

  In addition, since the refrigerant path is constituted by the heat transfer pipe 2 bent in a serpentine shape and the joint pipe 5 that connects the heat transfer pipes 2, the refrigerant path can be freely set. The heat transfer tubes 2 are configured to be seamless for each row or each stage, considering the uniformity of the manufacturing process, the loss in the manufacturing process, and the efficiency of the combined use of parts, and the ends of the heat transfer tubes 2 are connected to each other. It is desirable that the specifications be such that they are connected by the shunt 7.

  As described above, the heat exchanger according to the present invention is larger than the heat exchanger that forms a refrigerant path by welding a hairpin and a return bend used in a cooling device using an HFC refrigerant or an HCFC refrigerant. Therefore, it can be applied to a cooling device that requires a larger heat exchanger such as industrial equipment, as well as a refrigerator and a vending machine using a flammable refrigerant.

The perspective view of the heat exchanger in Embodiment 1 of this invention The perspective view of the fin tube assembly in the embodiment The perspective view of the heat exchanger tube of the heat exchanger in the embodiment The perspective view of the other Example of the heat exchanger tube of the heat exchanger in the embodiment The perspective view of the flat fin of the heat exchanger in the embodiment The perspective view of the heat exchanger in Embodiment 2 of this invention A perspective view of a conventional heat exchanger Front view of another conventional heat exchanger

Explanation of symbols

1 Heat Exchanger 2 Heat Transfer Tube 3 Flat Fin 4 Fin Tube Assembly 5 Joint Piping 6 Fin Collar

Claims (5)

  A fin tube assembly in which a heat transfer tube in which a flammable refrigerant flows is inserted and fixed to flat fins stacked while being spaced apart from each other, and at least two heat transfer tube ends of the fin tube assembly are connected to each other. A heat exchanger configured to be bent in a meandering manner so that at least one of the heat transfer tubes has two or more bent portions.   The heat exchanger according to claim 1, wherein the heat transfer tubes are configured to be seamless for each row or each stage.   The heat exchanger according to claim 2, wherein the heat transfer tube is bent into a flat shape.   The heat exchanger according to any one of claims 1 to 3, wherein the flat fin has a fin collar.   The heat exchanger according to any one of claims 1 to 4, wherein the refrigerant path includes a plurality of paths.

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