JP2004093057A - Heat exchanger and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce manufacturing cost of a heat exchanger for a hot water feeder requiring no blazing or no soldering of an outer pipe. <P>SOLUTION: The heat exchanger is provided with a core pipe 1 forming a water passage 2; the outer pipes 3A, 3B wound on an outer periphery of the core pipe 1 and forming cooling medium passages 4A, 4B having a smaller passage cross section than a passage cross section of the water passage 2. The core pipe 1 is enlarged after winding the outer pipes 3A, 3B. Thereby, the outer pipes 3A, 3B are integrally wound on the outer peripheral surface of the core pipe 1 with a predetermined or more of tightening force. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a heat exchanger such as a heat exchanger for a water heater for exchanging heat between water and a refrigerant, and a method for manufacturing the same.
[0002]
[Prior art]
As a well-known heat exchanger used for a heat exchanger for a water heater such as a heat pump water heater, for example, water as disclosed in Japanese Utility Model Laid-Open Publication No. 51-105158 is used. It consists of a double pipe with an inner pipe that circulates and an outer pipe that circulates refrigerant. This is wound into an elliptical spiral shape to form one heat exchanger unit, which is superposed on many stages and connected to each other. There is a double-pipe heat exchanger in which a heat exchanger main body is formed by doing so.
[0003]
In the case of such a double-pipe heat exchanger, if a hole is opened in the inner pipe through which water circulates due to corrosion, water and the refrigerant are mixed with each other. Operation had to be stopped. Therefore, as a countermeasure, a leak detecting tube having a leak detecting groove for guiding water leaked from the inner tube is provided outside the inner tube so as to detect the leak of the water as soon as possible. Therefore, in this configuration, the heat exchanger is substantially constituted by the triple pipe of the inner pipe, the leak detection pipe, and the outer pipe. Therefore, in the case of the same configuration, there is a problem that it is difficult to bend into an elliptical spiral shape and the number of parts is large, so that the manufacturing process is complicated and an increase in cost is unavoidable.
[0004]
Therefore, as a heat exchanger for a water heater as described above, for example, as shown in FIG. 6, refrigerant passages 4A and 4B are formed inside the long core tube 1 forming the water passage 2 inside. The first and second two outer tubes 3A and 3B having smaller outer diameters (passage diameters) than the core tube 1 are spirally wound at a predetermined pitch and brazed or soldered to form an oval. Are wound into a spiral shape to form one heat exchanger unit 10a, 10a..., And the heat exchanger units 10a, 10a. Thereafter, the inner ends of the core tube 1 and the outer tubes 3A and 3B are connected to each other by connecting tubes 7 and 11A and 11B, and are brazed or the like to form an integral shape. Passage 2 and the first and second Tube 3A, the refrigerant passages 4A and 3B side, the heat exchanger 10 which is the 4B has been proposed (see, for example, Japanese Patent Application No. 2001-20915).
[0005]
According to such a configuration of the heat exchanger 10, even if a hole is formed in the core tube 1 forming the water passage 2, unless the hole is formed in the outer tubes 3A and 3B, the refrigerant passages 4A and 4B are formed. There is no danger of water infiltrating into the outer tube 3A, and water leakage can be easily detected from the state of water leakage on the outer peripheral surface of the core tube 1 between the first and second outer tubes 3A and 3B. There is no need for a leak detection tube.
[0006]
[Problems to be solved by the invention]
However, in the case of the above-described configuration, equipment for brazing or soldering the outer tubes 3A, 3B to the core tube 1 at the time of manufacturing the heat exchanger units 10a, 10a. In addition, it is difficult to set the heat exchanger and manage the temperature and time, so that it is difficult to reduce the cost of the product.
[0007]
The present invention has been made to solve such a problem, after winding the outer tube around the core tube, instead of brazing or soldering, by expanding the core tube in some way, An object of the present invention is to provide a heat exchanger such as a heat exchanger for a water heater, and a method for manufacturing the same, in which the core pipe and the outer pipe are securely brought into close contact with each other to solve the above-mentioned problems.
[0008]
[Means for Solving the Problems]
The present invention is configured to include the following problem solving means in order to solve the above problems.
[0009]
(1) The heat exchanger according to the present invention is provided with a core tube 1 forming a water passage 2 and wound around the outer periphery of the core tube 1. A heat exchanger comprising outer tubes (3A, 3B) forming refrigerant passages (4A, 4B) having a smaller passage cross-sectional area, wherein the core tube (1) expands after winding the outer tubes (3A, 3B). Accordingly, the outer tubes 3A and 3B are integrally wound around the outer peripheral surface of the core tube 1 with a tightening force of a predetermined value or more.
[0010]
Therefore, according to such a configuration, there is no need for brazing or soldering the outer tubes 3A and 3B to the core tube 1 as in the related art, and equipment for them is not required, and the operation is simple, so that the manufacturing cost of the product is reduced. Is greatly reduced.
[0011]
(2) The heat exchanger according to the second aspect of the present invention is the heat exchanger according to the first aspect of the present invention, wherein the outer tube 3A, 3B has a contact surface with the outer tube 3A, 3B on the outer peripheral surface of the core tube 1. Is deformed in a concave shape corresponding to the outer peripheral surface shape of (1).
[0012]
Therefore, in this configuration, the contact area of the core tube 1 with the outer tubes 3A and 3B is increased, and the heat transfer performance is also improved.
[0013]
(3) The method of manufacturing a heat exchanger according to the third aspect of the present invention, wherein the core pipe 1 forming the water passage 2 and the outer periphery of the core pipe 1 are wound and provided. A method of manufacturing a heat exchanger, comprising outer tubes (3A, 3B) forming refrigerant passages (4A, 4B) having a passage sectional area smaller than the passage sectional area, wherein the outer tube (3A) is provided on the outer periphery of the core tube (1). , 3B, the core tube 1 is expanded so that the outer tubes 3A, 3B are integrally wound on the outer peripheral surface of the core tube 1 with a predetermined or more tightening force. It is characterized by having.
[0014]
Therefore, according to such a manufacturing method, it is not necessary to braze or solder the outer tubes 3A and 3B to the core tube 1 as in the related art, and equipment for these is not required. Cost is greatly reduced.
[0015]
(4) The invention according to claim 4 In the method for manufacturing a heat exchanger according to the invention, in the construction of the invention according to claim 3, the expansion of the core tube 1 is performed by using a high-pressure liquid pump 6 to seal the core tube 1. By supplying the liquid to the internal water passage 2 at a high pressure equal to or higher than a predetermined value, the operation is performed.
[0016]
As described above, the liquid (water or the like) is sealed in the water passage 2 in the core tube 1 around which the outer tubes 3A and 3B are wound, and the core tube 1 is expanded by applying a high pressure equal to or higher than a predetermined value. By doing so, sufficient adhesion and heat transfer area between the core tube 1 and the outer tubes 3A and 3B can be ensured by themselves, so that soldering is not required, and the expansion is performed by the high-pressure liquid pump 6. Can be realized if there is, so the equipment can be greatly simplified.
[0017]
In addition, in the case of this method, the bending of the core tube 1 may be performed before or after the expanding process, and can be arbitrarily selected depending on the working convenience at that time.
[0018]
(5) Invention of claim 5 In the method of manufacturing a heat exchanger according to the invention, the expansion of the core pipe 1 is larger than the diameter of the water passage 2 in the core pipe 1 in the structure of the invention of claim 3. The method is characterized in that a die 5 having a diameter is used and the die 5 is pressed into the water passage 2 in the core tube 1.
[0019]
Therefore, in the case of such a manufacturing method, the expansion ratio can be arbitrarily selected by selecting the size of the die 5, and the core tube 1 and the outer tubes 3A and 3B can be securely brought into close contact with each other.
[0020]
【The invention's effect】
As a result, according to the present invention, it is possible to provide a low-cost and high-performance heat exchanger suitable for a water heater that reliably solves the above-described conventional problems.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, some embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0022]
(Embodiment 1)
First, FIGS. 1 to 3 show a configuration of a heat exchanger according to Embodiment 1 of the present invention suitable for forming, for example, a heat exchanger for a water heater, and a manufacturing method for manufacturing the same. I have. FIG. 1 shows a configuration of one heat exchanger unit 10a of the heat exchangers 10 of FIGS. 7 and 8 described above, and FIG. 2 shows a configuration of a main part of the heat exchanger unit 10a in the course of manufacturing. FIG. 3 shows the configuration of the heat exchanger unit 10a after the production is completed.
[0023]
In these figures, reference numeral 1 denotes a core pipe having a circular pipe structure in which a water passage 2 having a circular cross section is formed. The core tube 1 has a predetermined length and a predetermined diameter.
[0024]
On the other hand, reference numerals 3A and 3B denote first and second outer pipes having a circular pipe structure in which refrigerant passages 4A and 4B having a circular cross section are formed, respectively. As shown in FIG. 2, for example, the first and second outer tubes 3A and 3B are spaced apart from each other at predetermined intervals on the outer peripheral surface of the core tube 1 by a predetermined distance in parallel along the longitudinal direction. In a state where the coil is spirally wound with a winding angle and is finally manufactured by a later-described expanding operation, a core is formed on the outer peripheral surface of the core tube 1 as shown in FIG. A state in which a large tightening force (binding force) of a predetermined value or more is maintained against the pipe 1 and the pipe 1 is pressed against the pipe 1 via the concave surfaces 1c, 1c,. Thus, the core tube 1 is integrated. After the completion of the production, a refrigerant having a predetermined value or more, for example, a carbon dioxide refrigerant flows through each of the refrigerant passages 4A and 4B in the first and second outer tubes 3A and 3B.
[0025]
The heat exchanger unit 10a having this configuration is manufactured, for example, as follows.
[0026]
(1) First Manufacturing Step First, first and second outer tubes 3A and 3B are spirally wound around the outer peripheral surface of the core tube 1. In this state, between the outer peripheral surface of the core tube 1 and the first and second outer tubes 3A and 3B, for example, as shown in an enlarged view in FIG. The pressure contact force and the degree of adhesion between the tube 1 and the first and second outer tubes 3A, 3B are not always sufficient.
[0027]
(2) Second Manufacturing Step Next, the core tube 1 in the state of FIG. 2 wound with the first and second outer tubes 3A and 3B is bent into, for example, an oblong spiral shape as shown in FIG. Processing is performed, and the opening at the inner end 1b side is sealed with a desired sealing member 5 such as a cap capable of venting air as necessary, so that the water passage 2 in the core tube 1 is sealed.
[0028]
(3) Third Manufacturing Step Next, as shown in FIG. 1, a high-pressure liquid pump 6 for expanding the pipe is formed on the opening of the outer end 1a of the spiral core tube 1 whose inner end 1b is sealed. Liquid discharge pipe 6a is connected.
[0029]
(4) Fourth Manufacturing Step Next, in a state where the high-pressure pipe expansion liquid pump 6 is connected as shown in FIG. 3, the high-pressure pipe expansion liquid pump 6 is driven, and first, a water passage in the core pipe 1 is formed. 2 is filled with a liquid such as water while evacuating the internal air. After that, the sealing member 5 is reliably maintained in a sealing state having high pressure resistance, the hydraulic pressure in the water passage 2 is increased to a predetermined value or more, The entire pipe 1 from the outer end 1a to the inner end 1b is expanded radially outward uniformly, as shown in FIG. 3, for example, and its outer diameter is increased by a predetermined dimension.
[0030]
As a result, as is apparent from FIG. 3, the first and second outer tubes 3A and 3B have a tightening force (binding force) relatively higher than a predetermined value with respect to the outer peripheral surface of the core tube 1. (Absorption of spring back), the cross section of which is slightly deformed into an elliptical shape, and a wide contact is made via concave portions 1c, 1c,... The area becomes in pressure contact with the area (surface contact), and the heat transfer performance between the two is improved to a level at which brazing or soldering becomes unnecessary.
[0031]
In this case, when the biting force of the outer tubes 3A, 3B is increased and the amount of deformation (depth) of the concave portions 1c, 1c,... Is increased, a spiral groove is formed on the inner peripheral surface of the core tube 1. And a turbulence effect can be generated.
[0032]
In the above case, the bending process of the core tube 1 may be performed before the expanding process, or may be arbitrarily selected depending on the working convenience at that time.
[0033]
As described above, the liquid (water or the like) is sealed in the water passage 2 in the core tube 1 in which the outer tubes 3A and 3B are wound, and the core tube 1 is expanded by applying a high pressure equal to or higher than a predetermined value. By doing so, sufficient adhesion and heat transfer area between the core tube 1 and the outer tubes 3A and 3B can be ensured by themselves, so that brazing or soldering as in the conventional case is unnecessary, and the expansion is performed at a high pressure. Since the liquid pump 6 can be easily realized, the equipment can be greatly simplified.
[0034]
When the heat exchanger 10 to be finally assembled is composed of a plurality of heat exchanger units 10a, 10a,... As shown in FIGS. By arbitrarily selecting the order of each operation such as “bending”, “expansion”, and “connection of each unit (such as brazing)”, different operation characteristics can be obtained. Now, an example is shown below.
[0035]
{Circle around (1)} Expanding the core tube 1 before bending it ... A uniform expansion state is obtained.
[0036]
{Circle around (2)} Bending the core tube 1 before expanding the tube. Bending of the core tube 1 becomes easy.
[0037]
{Circle around (3)} Connecting each unit before bending the core tube 1 and expanding the tube ... Only one expansion operation is required.
[0038]
{Circle around (4)} Connecting each unit after bending and expanding the core tube 1. Even if there are units with different diameters or wall thicknesses of the core tube 1, by changing the expansion pressure for each unit, Can be easily handled.
[0039]
When the tube is expanded using the hydraulic pressure as described above, the contact surface of the core tube 1 with the outer tubes 3A, 3B is recessed into the concave portions 1c, 1c,. , 3B, the wall surface rises, the contact area is further increased, and the spiral tube forming effect is enhanced.
[0040]
(Embodiment 2)
Next, FIGS. 4 and 5 show a configuration and a manufacturing method of a main part of a heat exchanger according to Embodiment 2 of the present invention.
[0041]
In this embodiment, first, first and second outer tubes 3A and 3B are wound around the outer periphery of the core tube 1 as shown in FIG. As shown in FIG. 4 and FIG. 5, a pipe-expanding dice 5 having an egg-shaped pipe-expanding portion 5a at its tip is passed through the inside of the tube 1 and pushed from the rear end 5b side to press-fit the core tube 1 so as to expand the core tube 1. After the expansion, the core tube 1 is bent to finish the same heat exchanger unit 10a as described above.
[0042]
Therefore, in the case of such a manufacturing method, the expansion ratio can be arbitrarily selected by selecting the size (outer diameter size) of the expanded portion 5a of the expanding die 5 and the core tube 1 and the outer tubes 3A and 3B can be formed. It can be surely adhered.
[0043]
And, of course, also in this embodiment, the configuration of the finally formed heat exchanger units 10a and 10b is the same as that of the above-described first embodiment, and has the same operation and effect. I have. That is, in a state where the manufacture is finally completed, the outer tubes 3A and 3B maintain a large fastening force (binding force) on the outer peripheral surface of the core tube 1 with respect to the core tube 1 by a predetermined value or more. . And the core tube 1 integrated with the core tube 1 in a state of being in pressure contact with a large contact area via the concave surfaces 1c formed on the outer peripheral surface by the expanding force at the time of expanding the tube. Become.
[0044]
(Modification)
In the case where the expansion is performed by the expansion die 5 as in the second embodiment, the expansion die 5 is not limited to, for example, only the mandrel method described above. .. May be connected in a chain form from one end to the other end in the core tube 1 and pulled out from the other end.
[0045]
By doing so, flexibility can be exhibited with respect to a change in the shape of the core tube 1 as compared with the case of the mandrel method, and processing becomes easier.
[Brief description of the drawings]
FIG. 1 is an overall view showing a configuration and a manufacturing method of a hot water supply heat exchanger according to Embodiment 1 of the present invention.
FIG. 2 is an enlarged view of a first state showing a configuration of a main part of the heat exchanger and an operation of a manufacturing process in a manufacturing method.
FIG. 3 is an enlarged view of a second state showing a configuration of a main part of the heat exchanger and an operation of a manufacturing process in a manufacturing method.
FIG. 4 is a cross-sectional view illustrating a configuration of a main part of a heat exchanger for hot water supply according to Embodiment 2 of the present invention and a first manufacturing process in a manufacturing method thereof.
FIG. 5 is a cross-sectional view showing a second manufacturing step in the manufacturing method.
FIG. 6 is a diagram showing a configuration of a main part of a conventional general hot water supply heat exchanger.
FIG. 7 is a plan view showing an example of an assembly form of the hot water supply heat exchanger body.
FIG. 8 is a side view of the same.
[Explanation of symbols]
1 is a core tube, 2 is a water passage, 3A is a first outer tube, 3B is a second outer tube, 4A is a first refrigerant passage, 4B is a second refrigerant passage, 5 is a die for expanding, 6 is This is a high-pressure liquid pump for pipe expansion.

Claims (5)

A core tube (1) forming a water passage (2), and wound around the outer periphery of the core tube (1) and provided with a passage cross-sectional area smaller than the passage cross-sectional area of the water passage (2). A heat exchanger comprising outer tubes (3A) and (3B) forming refrigerant passages (4A) and (4B), wherein the core tube (1) is formed of the outer tubes (3A) and (3B). The outer pipes (3A) and (3B) are integrally wound on the outer peripheral surface of the core pipe (1) with a tightening force of a predetermined value or more by being expanded after winding. A heat exchanger. The contact surface of the outer peripheral surface of the core tube (1) with the outer tubes (3A) and (3B) is deformed into a concave shape corresponding to the outer peripheral surface shape of the outer tubes (3A) and (3B). The heat exchanger according to claim 1, wherein: A core tube (1) forming a water passage (2), and wound around the outer periphery of the core tube (1) and provided with a passage cross-sectional area smaller than the passage cross-sectional area of the water passage (2). A method of manufacturing a heat exchanger comprising outer tubes (3A) and (3B) forming refrigerant passages (4A) and (4B), wherein the outer tube (3A) is provided on the outer periphery of the core tube (1). ) And (3B) are wound, and then the core tube (1) is expanded so that the outer tubes (3A) and (3B) are fastened to the outer peripheral surface of the core tube (1) by a predetermined value or more. A method for manufacturing a heat exchanger, wherein the heat exchanger is integrally wound with force. Expansion of the core pipe (1) is performed by using a high-pressure liquid pump (6) and supplying a liquid at a high pressure equal to or higher than a predetermined value to a water passage (2) in the sealed core pipe (1). A method for manufacturing a heat exchanger. For expanding the core tube (1), a die 5 having an outer diameter larger than the diameter of the water passage (2) in the core tube (1) is used, and the die 5 is connected to the water passage ( 2) A method for manufacturing a heat exchanger, wherein the method is performed by press-fitting.

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