JP2006284009A - Method of manufacturing twisted tube-type heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform sound joining without needing large-scaled expensive equipment, coating of flux and cleaning to eliminate the flux. <P>SOLUTION: A refrigerant tube 3 is wound on water piping 2 along a plurality of spiral grooves 2a formed on an outer periphery of the water piping 2, the water piping 2 on which the refrigerant tube 3 is wound is bent to a prescribed dimension, the bent water piping 2 and the refrigerant tube 3 are coated with thermosetting resin adhesive 4 having high heat conductivity, and the water piping 2 and the refrigerant tube 3 coated with the thermosetting resin adhesive 4 are heated in the atmosphere to be closely joined to each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a torsion tube heat exchanger, and more particularly, to a method for manufacturing a heat exchanger in which a refrigerant pipe is wound around an outer periphery of a water pipe serving as a core pipe.

  Conventionally, a torsion tube type heat exchanger in which a refrigerant tube is wound around the outer periphery of a water pipe serving as a core tube has been known (see, for example, Patent Document 1).

  Moreover, in such a thing, in order to make the water pipe used as a core pipe and the refrigerant pipe wound around it close, the water pipe used as a core pipe is expanded by applying hydraulic pressure to the inside thereof, The pipe is expanded through a dicing die inside the water pipe to be a pipe, thereby relatively increasing the tightening force of the refrigerant pipe, and the refrigerant pipe is intruded into the outer peripheral surface of the water pipe to be in close contact therewith. A thing is also known (for example, refer patent document 2).

  In addition, in plate-type heat exchangers, a plurality of plate-like plates forming flow paths are overlapped and joined using a high melting point solder such as phosphor copper solder or silver solder or a low melting point solder such as solder. Known (for example, Patent Document 3).

JP 2002-228370 A JP 2004-93057 A JP 2002-107074 A

However, in the case of a system in which the water pipe serving as the core pipe is expanded by applying a hydraulic pressure (for example, hydraulic pressure) to the inside, the water pipe and the refrigerant pipe wound around the water pipe are in close contact with each other. Tube expansion equipment is required. In addition, it is necessary to clean and dry the water pipe for the purpose of oil removal after the pipe expansion, and to strictly control contamination such as residual oil.
Also, in the case of a system in which the water pipe and the refrigerant pipe wound around the water pipe are in close contact with each other by expanding the pipe through the expansion pipe inside the water pipe that becomes the core pipe, the inner surface of the water pipe is damaged due to the influence of the expansion pipe. Etc. are formed and cause corrosion.

  In addition, in the case of joining using a high melting point solder such as phosphor copper brazing or silver brazing, the joining temperature is high and an oxide film is formed on the surface of the base material. is there. For this reason, installation of a large-scale and expensive reducing atmosphere continuous furnace facility is indispensable. Furthermore, depending on the combination with the base material, it is necessary to apply a flux (oxide film removing agent) and perform post-cleaning for the purpose of removing the oxide film on the surface of the base material.

  By the way, in joining other than the reducing atmosphere continuous furnace, high-frequency joining, torch (gas) joining, and the like are conceivable. However, joining in a torsion tube heat exchanger requires joining in a reducing atmosphere. Replacement equipment for oxidation brazing is required. Furthermore, brazing is basically based on the use of capillary action as a joining principle, and in order to achieve sound joining, the gap between the water pipe and the refrigerant pipe must be thoroughly managed.

  Also, in the case of joining using a low melting point solder such as solder, a reducing atmosphere facility is required, and depending on the solder material, flux application and post-cleaning are required. Furthermore, when the base material is copper, there is a concern about the phenomenon of copper erosion due to solder.

  The present invention has been made to solve the above-described problems, and does not require large-scale and expensive equipment, and does not require cleaning for the purpose of flux application or removal thereof, and enables sound bonding. It is an object of the present invention to provide a method for manufacturing a twisted tube heat exchanger that can be used.

  The method for manufacturing a twisted tube heat exchanger according to the present invention includes a step of winding a refrigerant pipe along a spiral groove on a water pipe having a plurality of spiral grooves on the outer periphery, and a water pipe around which the refrigerant pipe is wound. A process of bending the pipe into a predetermined dimension, a process of applying a thermosetting resin adhesive having high thermal conductivity to the bent water pipe and refrigerant pipe, and a water pipe and refrigerant pipe coated with the thermosetting resin adhesive It is characterized by having a step of tightly joining the water pipe and the refrigerant pipe by heating the pipe in the atmosphere.

  According to the manufacturing method of the twisted tube heat exchanger of the present invention, by applying a thermosetting resin adhesive having high thermal conductivity to the bent water pipe and the refrigerant pipe, and heating them in the atmosphere, Since the water pipe and the refrigerant pipe are tightly joined, they can be joined in a low temperature zone where the generation of an oxide film is small and without the need for an oxidation remover. For this reason, large-scale and expensive equipment is not required, and a flux application process and a cleaning process for the purpose of flux removal can be omitted.

Embodiment 1 FIG.
The present invention will be described below with reference to illustrated embodiments.
FIG. 1 is a process diagram showing a manufacturing method of a torsion tube heat exchanger according to Embodiment 1 of the present invention, and FIG. 2 is an overall configuration diagram of the torsion tube heat exchanger produced by the manufacturing method of the present invention. 3 is a cross-sectional view of the main part of the torsion tube heat exchanger, FIG. 4 is an enlarged cross-sectional view of the main part showing an application example of the thermosetting resin adhesive to the torsion tube heat exchanger, and FIG. The principal part expanded sectional view which shows the other example of application | coating of the thermosetting resin-type adhesive agent to a type | mold heat exchanger, FIG. 7 is an explanatory diagram showing an example of heating, FIG. 7 is an explanatory diagram showing an example of heating by a high frequency power supply device of a torsion tube heat exchanger coated with the thermosetting resin adhesive, and FIG. 8 is an illustration of the torsion tube heat exchanger. FIG. 9 is a cross-sectional view of the main part showing the state after bonding the adhesive, and FIG. 9 is a graph showing the adhesive curing conditions of the twisted tube heat exchanger in relation to temperature and time. FIG 10 is a bar graph showing the relationship between the thermally conductive filler content used in torsion tube type heat exchanger thermosetting resin adhesive and thermal conductivity.

  As shown in FIGS. 2 and 3, the torsion tube heat exchanger 1 according to the present embodiment includes a torsion tube having a plurality of spiral grooves 2a on the outer periphery, that is, a water pipe 2, and a water pipe 2 with a spiral groove 2a. It is comprised from the refrigerant | coolant pipe | tube 3 wound along. FIG. 2 shows a cross section cut along the tube axis of the water pipe 2.

  The location where the thermosetting resin-based adhesive 4 that joins the water pipe 2 and the refrigerant pipe 3 is applied differs depending on the manufacturing method described later, and when the refrigerant pipe 3 is wound around the spiral groove 2a of the water pipe 2, When the thermosetting resin adhesive is first applied to the spiral groove 2a of the water pipe 2 as shown in FIG. 4, it becomes the bottom of the spiral groove 2a as shown in FIG.

  There are also two methods of heating after applying the thermosetting resin adhesive to join the water pipe 2 and the refrigerant pipe 3, and one is twisted in the atmospheric high-temperature tank (or furnace) 5 as shown in FIG. This is a method in which the tubular heat exchanger 1 is accommodated and the entire twisted tubular heat exchanger 1 is heated, and the other one uses a high frequency power supply device 6 as shown in FIG. In this method, 6a is moved and heated.

  Next, the manufacturing method of the twisted tube heat exchanger of this embodiment is demonstrated based on FIG. 1 and referring FIG. 2 thru | or FIG. First, the refrigerant pipe 3 is wound and fitted along the spiral groove 2a in the water pipe 2 provided with a plurality of spiral grooves 2a on the outer periphery (FIG. 1 (a)). Next, the water pipe 2 around which the refrigerant pipe 3 is wound is bent into a predetermined dimension by a bending apparatus 7 (FIG. 1B), and then thermosetting having high thermal conductivity using an automatic application apparatus 8 such as a dispenser. The resin adhesive 4 is applied (FIG. 1 (c)). After the refrigerant pipe 3 is wound around the spiral groove 2a of the water pipe 2 and bent, the thermosetting resin-based adhesive 4 is applied, so that the water into which the refrigerant pipe 3 is fitted as shown in FIG. The method of applying the thermosetting resin adhesive 4 only to the surface (for example, the upper surface) of the pipe 2 is the best. At that time, it is important to control the application amount of the thermosetting resin adhesive 4 and the viscosity of the adhesive. Thereafter, the water pipe 2 and the refrigerant pipe 3 coated with the thermosetting resin adhesive 4 are heated in the atmosphere. That is, the twisted tube heat exchanger 1 to which the thermosetting resin adhesive 4 is applied is housed in an atmospheric high-temperature tank 5 and heated in a temperature range of 200 ± 50 ° C. (FIG. 1 (d), FIG. 6). The water pipe 2 and the refrigerant pipe 3 are tightly joined by curing the thermosetting resin adhesive 4. When the high-frequency power supply device 6 as shown in FIG. 7 is used as means for heating the torsion tube heat exchanger 1 coated with the thermosetting resin adhesive 4 in the atmosphere, it has a meandering shape after bending. Equipment for moving and controlling the heating coil 6a along the torsion tube heat exchanger 1 is required, but it goes without saying that a heating method using this high-frequency power supply device 6 can also be adopted.

  Thus, according to the manufacturing method of the twisted tube heat exchanger of this embodiment, since the thermosetting resin adhesive 4 having high thermal conductivity is used as a joining means of the water pipe 2 and the refrigerant pipe 3, Bonding in a short time is possible, and cleaning for the purpose of flux application and removal thereof is also unnecessary.

  FIG. 8 shows a cross-sectional view of the joined torsion tube heat exchanger 1 after joining. In the case of the conventional method of joining using a brazing material such as phosphor copper solder or solder, since the joining is performed using the capillary phenomenon, the gap management between the water pipe 2 and the refrigerant pipe 3 is set to an appropriate value (from 0.06 mm to 0). 20 mm). When the refrigerant pipe 3 is wound around and fitted into the water pipe 2, the pipe is wound while applying an appropriate tension. However, in the case of the thermosetting resin adhesive 4, since it is not joining utilizing capillary action, strict gap management is not required, and sound joining is possible.

  FIG. 9 shows the curing conditions of the thermosetting resin adhesive 4, where the vertical axis represents temperature and the horizontal axis represents the time until curing. Curing is performed at 240 ° C. for about 10 seconds, 180 ° C. for about 60 seconds, and 150 ° C. for about 90 seconds. Under these curing conditions, there was no difference in the adhesion of the joints, and no defects such as voids occurred.

  In addition, the automatic application device 8 is provided with a heater that can supply heat at around 50 ° C. in order to perform application more smoothly.

  FIG. 10 shows a comparison of heat transfer performance depending on whether or not the thermosetting resin adhesive 4 contains a metallic heat conductive filler. The heat conductivity of a normal resin adhesive (no metallic heat conductive filler) is 0.5 W. In the case of a thermosetting resin adhesive containing 30 vol% metal filler (for example, one-component epoxy resin), the thermal conductivity is 2.0 W / m · K, almost 4 times that of the / m · K level. When 60 vol% of the metal filler is contained, the thermal conductivity is 3.0 W / m · K, which is almost 6 times.

  However, in general, the thermal conductivity of copper is defined as about 400 W / m · K, and the thermal conductivity of tin is defined as about 70 W / m · K. Phosphor copper solder with a copper content of 90 vol% and tin content of 99 vol% Compared with solder, the thermal conductivity of the resin adhesive is about 1/100 to 1/20 times.

  However, the present inventors have found that the thermal conductivity of a single bonding material, such as a brazing material and a resin adhesive, is not necessarily proportional to the heat exchange performance of the torsion tube heat exchanger as a whole. It became clear by experiment. For example, in the heat exchange performance of the torsion tube heat exchanger as a whole, assuming that 100 is the case where the copper content is 90 vol% and the copper content is 100 vol., The tin content is 99 vol%. . Even when bonded with a thermosetting resin adhesive with a thermal conductivity of 2.0 W / m · K, the overall heat exchange performance of the torsion tube heat exchanger is around 80, and the difference in thermal conductivity between the bonding materials alone Is not seen.

  In other words, when a thermosetting resin adhesive with a thermal conductivity of 2.0 W / m · K or higher is used as the bonding material, considering the heat exchange performance variation of the heat exchanger alone, the total pipe length is 10 to 20%. It becomes possible to use it without any problems by measures such as increasing it.

  For reference, a thermosetting resin adhesive with a thermal conductivity of 0.5 W / m · K does not exhibit a heat transfer performance of 40, and at least a thermosetting resin system with a thermal conductivity of 2.0 W / m · K or less. With the adhesive, it was not possible to obtain the same heat exchange performance as compared with heat exchangers joined with phosphor copper solder or solder material.

  Therefore, by using an adhesive having a thermal conductivity of 2.0 W / m · K or more as the thermosetting resin adhesive, it is possible to ensure heat exchange performance with relatively no problem as a torsion tube heat exchanger. it can.

  As described above, in joining the torsion tube heat exchanger, the water pipe 2 and the refrigerant pipe 3 are joined using the thermosetting resin adhesive 4 having high thermal conductivity, so that a large-scale reducing atmosphere furnace or the like can be used. Therefore, it is possible to perform bonding in a low temperature zone in the atmosphere in a short time, and before and after treatment such as flux application or post-cleaning is not required, and sound bonding is possible. Furthermore, by containing 30 vol% or more of the metallic heat conductive filler in the thermosetting resin adhesive 4, it was possible to ensure heat exchange performance with no problems as a twisted tube heat exchanger.

Embodiment 2. FIG.
FIG. 11 is a process diagram showing a method for manufacturing a twisted tube heat exchanger according to Embodiment 2 of the present invention. In the drawing, the same parts as those in Embodiment 1 are given the same reference numerals. In the description, reference is made to FIG. 2 to FIG.

  As shown in FIG. 11, in the manufacturing method of the twisted tube heat exchanger of this embodiment, first, the refrigerant pipe 3 is wound around the water pipe 2 provided with a plurality of spiral grooves 2a on the outer periphery along the spiral grooves 2a. (Fig. 11 (a)). Next, the thermosetting resin adhesive 4 having high thermal conductivity is applied to the water pipe 2 around which the refrigerant pipe 3 is wound using an automatic application device 8 such as a dispenser (FIG. 11B). Here, as the thermosetting resin adhesive 4, as in the first embodiment, an adhesive that satisfies the conditions of a temperature of 200 ± 50 ° C. and a curing time of 90 seconds or less, or a thermal conductivity of 2.0 W / m. -For example, a one-component epoxy resin containing 30 vol% or more of an adhesive that is K or higher or a metal filler is used. Thereafter, the water pipe 2 and the refrigerant pipe 3 coated with the thermosetting resin adhesive 4 are sequentially heated from one end side to the other end side using the high frequency power supply device 6 and at the same time the heat (bonding heat) at this time Using the bending apparatus 7 to bend the part that needs to be bent, the process of tightly joining the water pipe 2 and the refrigerant pipe 3, and bending the water distribution pipe 2 and the refrigerant pipe 3 to a predetermined dimension And the step of performing are simultaneously performed (FIG. 11C). At that time, the management of the curing rate is important. In addition, when applying the thermosetting resin adhesive 4, by stopping the supply of the adhesive only at the bent portion, the entire adhesive area is reduced, but a sound bending process is possible.

  Also in the manufacturing method of the torsion tube type heat exchanger of this embodiment, since the thermosetting resin adhesive 4 having high thermal conductivity is used as the joining means of the water pipe 2 and the refrigerant pipe 3, it can be performed in the air in a short time. In addition, there is no need for flux application or cleaning for the purpose of removing the flux, and the same operations and effects as those of the first embodiment are achieved.

  Further, in order to apply the thermosetting resin adhesive 4 before bending, a method of applying the thermosetting resin adhesive 4 only to the upper surface of the water pipe 2 into which the refrigerant pipe 3 is fitted as shown in FIG. In addition, a method of applying the thermosetting resin adhesive 4 spirally along the water pipe 2 into which the refrigerant pipe 3 is fitted may be employed. In that case, equipment for rotating the water pipe 2 fitted with the refrigerant pipe 3 is required. However, since it can be applied evenly to the close contact area, it is considered that the thermosetting resin adhesive 4 spreads to the lower side. There is an advantage that it is relatively easy to manage with respect to the coating method of only the upper surface.

Embodiment 3 FIG.
FIG. 12 is a process diagram showing a method for manufacturing a torsion tube heat exchanger according to Embodiment 3 of the present invention. In the figure, the same parts as those in Embodiment 1 are given the same reference numerals. In the description, reference is made to FIG. 2 to FIG.

  As shown in FIG. 12, the manufacturing method of the twisted tube heat exchanger according to the present embodiment is as follows. First, a water pipe 2 having a plurality of spiral grooves 2a on the outer periphery, and an automatic dispenser or the like along the bottom of the spiral groove 2a. The thermosetting resin adhesive 4 having high thermal conductivity is applied using the coating device 8 (FIG. 12A). As the thermosetting resin adhesive 4, as in the first embodiment, the adhesive satisfies the conditions of a temperature of 200 ± 50 ° C. and a curing time of 90 seconds or a thermal conductivity of 2.0 W / m · K. For example, a one-component epoxy resin containing 30 vol% or more of the above adhesive or metal filler is used. Next, the refrigerant pipe 3 is wound around and fitted in the water pipe 2 to which the thermosetting resin adhesive 4 is applied (FIG. 12B). Next, the water pipe 2 around which the refrigerant pipe 3 is wound is bent to a predetermined dimension by the bending apparatus 7 (FIG. 12 (c)), and then the torsion pipe heat exchange in which the thermosetting resin adhesive 4 has already been applied. The container 1 is accommodated in the atmospheric high-temperature tank 5 and heated in a temperature range of 200 ± 50 ° C. (FIG. 12D), and the thermosetting resin adhesive 4 is cured, so that the water pipe 2 and the refrigerant pipe 3 is tightly bonded. As a means for heating the torsion tube heat exchanger 1 coated with the thermosetting resin adhesive 4 in the atmosphere, a heating method using a high frequency power supply device 6 as shown in FIG. 7 can be adopted here. Needless to say.

  Thus, also in the manufacturing method of the twisted tube heat exchanger of the present embodiment, since the thermosetting resin adhesive 4 having high thermal conductivity is used as a joining means of the water pipe 2 and the refrigerant pipe 3, In addition, bonding in a short time is possible, and cleaning for the purpose of flux application and removal thereof is not necessary, and the same operations and effects as those of the first embodiment are achieved.

  Moreover, in this embodiment, since the thermosetting resin adhesive 4 is applied before the refrigerant pipe 3 is wound around the spiral groove 2a of the water pipe 2, and the refrigerant pipe 3 is wound after the application, the slip suppression is suppressed. However, since it is applied before bending, a method of applying a spiral along the spiral groove 2a of the water pipe 2 can be selected. Further, since the refrigerant tube 3 wound along the spiral groove 2a after application functions as a lid of the adhesive application part and adhesion of the adhesive to the equipment is suppressed, after performing normal bending, FIG. Heating in the atmospheric high-temperature tank 5 shown in FIG. That is, it is not necessary to perform the bending step and the heating simultaneously while managing the curing rate, and it is possible to perform the bonding while suppressing the decrease in the adhesion area.

It is process drawing which shows the manufacturing method of the twisted tube heat exchanger which concerns on Embodiment 1 of this invention. 1 is an overall configuration diagram of a torsion tube heat exchanger produced by a method for manufacturing a torsion tube heat exchanger according to Embodiment 1 of the present invention. FIG. It is principal part sectional drawing of the twisted tube heat exchanger which concerns on Embodiment 1 of this invention. It is a principal part expanded sectional view which shows the example of application | coating of the thermosetting resin adhesive in the manufacturing method of the twisted tube heat exchanger which concerns on Embodiment 1 of this invention. It is a principal part expanded sectional view which shows the other application example of the thermosetting resin-type adhesive agent in the manufacturing method of the twisted tube type heat exchanger which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the example of a heating by the atmospheric high temperature tank of the torsion tube type heat exchanger with which the thermosetting resin adhesive was apply | coated in the manufacturing method of the torsion tube type heat exchanger which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the example of a heating by the high frequency power supply device of the twisted tube type heat exchanger apply | coated with the thermosetting resin adhesive in the manufacturing method of the twisted tube type heat exchanger which concerns on Embodiment 1 of this invention. It is principal part sectional drawing which shows the state after adhesive bonding of the torsion tube type heat exchanger by the manufacturing method of the torsion tube type heat exchanger which concerns on Embodiment 1 of this invention. It is a graph which shows the adhesive hardening conditions in the manufacturing method of the twisted tube heat exchanger which concerns on Embodiment 1 of this invention with the relationship between temperature and time. It is a bar graph which shows the relationship between the heat conductive filler content of the thermosetting resin adhesive used for the manufacturing method of the twisted tube heat exchanger which concerns on Embodiment 1 of this invention, and heat conductivity. It is process drawing which shows the manufacturing method of the twisted tube type heat exchanger which concerns on Embodiment 2 of this invention. It is process drawing which shows the manufacturing method of the twisted tube type heat exchanger which concerns on Embodiment 3 of this invention.

Explanation of symbols

1 torsion tube heat exchanger, 2 water piping, 2a spiral groove, 3 refrigerant tube, 4 thermosetting resin adhesive, 5 atmospheric high temperature bath (or furnace), 6 high frequency power supply device, 7 bending processing device, 8 automatic coating apparatus.

Claims (6)

A step of winding a refrigerant pipe along the spiral groove on a water pipe provided with a plurality of spiral grooves on the outer periphery;
Bending the water pipe around which the refrigerant pipe is wound to a predetermined dimension;
Applying a thermosetting resin adhesive having high thermal conductivity to the bent water pipe and the refrigerant pipe;
A step of closely bonding the water pipe and the refrigerant pipe by heating the water pipe and the refrigerant pipe coated with the thermosetting resin adhesive in the atmosphere;
The manufacturing method of the twisted tube type heat exchanger characterized by having. A step of winding a refrigerant pipe along the spiral groove on a water pipe provided with a plurality of spiral grooves on the outer periphery;
Applying a thermosetting resin adhesive having high thermal conductivity to a water pipe wrapped with a refrigerant pipe;
By sequentially heating the water pipe and refrigerant pipe coated with thermosetting resin adhesive from one end side to the other end side, by using the heat at this time to bend the parts that need to be bent A method for manufacturing a torsion tube heat exchanger, wherein the step of tightly joining the water pipe and the refrigerant pipe and the step of bending the water pipe and the refrigerant pipe to a predetermined dimension are simultaneously performed. Applying a thermosetting resin adhesive having high thermal conductivity along the bottom of the spiral groove to a water pipe provided with a plurality of spiral grooves on the outer periphery;
A process of winding a refrigerant pipe along the spiral groove on a water pipe coated with a thermosetting resin adhesive;
Bending the water pipe around which the refrigerant pipe is wound to a predetermined dimension;
Heating and bending the water pipe and the refrigerant pipe in the atmosphere, thereby closely bonding the water pipe and the refrigerant pipe;
The manufacturing method of the twisted tube type heat exchanger characterized by having.   The adhesive according to any one of claims 1 to 3, wherein an adhesive satisfying a condition of a curing time of 90 seconds or less at a temperature of 200 ± 50 ° C is used as the thermosetting resin adhesive having high thermal conductivity. Of manufacturing a twisted tube heat exchanger.   The twist according to any one of claims 1 to 3, wherein an adhesive having a thermal conductivity of 2.0 W / m · K or more is used as the thermosetting resin adhesive having high thermal conductivity. A method for manufacturing a tubular heat exchanger. The twist according to any one of claims 1 to 3, wherein a one-component epoxy resin containing 30 vol% or more of a metallic thermal conductive filler is used as the thermosetting resin adhesive having high thermal conductivity. A method for manufacturing a tubular heat exchanger.

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