JP2013053804A - Structure of triple pipe, and heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of a triple pipe, and a heat exchanger capable of improving heat exchanger effectiveness and being miniaturized.SOLUTION: In the structure of the triple pipe and the heat exchanger of the embodiment, three pipes are fitted in a state of being overlapped to each other, and an outer pipe, an intermediate pipe and an inner pipe are successively overlapped from an outer side. The intermediate pipe is shaped into the waveform in which peak sections and trough sections are alternately disposed in the circumferential direction of the intermediate pipe, the peak sections are formed in a state of being kept into contact with the outer pipe, and the trough sections are formed in a state of being kept into contact with the inner pipe.

Description

  Embodiments of the present invention relate to a triple-tube structure and a heat exchanger in which three tubes are fitted to overlap each other and have an outer tube, an intermediate tube, and an inner tube from the outside in the overlapping order.

  For example, a triple pipe is used for a heat exchanger for heating water in a bathtub. The inner pipe and the outer pipe of the triple pipe are connected to each other by a connection path so that the water in the bathtub that has entered from the inner pipe returns (circulates) back to the bathtub through the outer pipe. On the other hand, warm water circulates in the intermediate pipe. Thereby, the heat of the warm water in the intermediate pipe is transmitted to the inner pipe and the outer pipe, and the water in the bathtub is heated when passing through the inner pipe and the outer pipe. As the water in the bathtub circulates in this manner, the temperature rises (for example, Patent Document 1).

  Generally, in a triple tube, in order to improve the heat transfer effect between the media in each tube, it is necessary to widen the area (heat transfer area) where the tubes overlap each other. As an example of increasing the heat transfer area, there is a method of lengthening the overlapping portion. As another example, there is a method of increasing the diameters of three tubes.

JP-A-6-229617

  However, in the method of lengthening the place where the three tubes overlap and the method of increasing the diameter of the three tubes, there is a problem that the triple tube becomes large and the heat exchanger that accommodates the triple tube becomes large. .

  Moreover, in the technique described in the said patent document, there existed a problem that a triple pipe became large by the part which provided the connection path for connecting an inner pipe and an outer pipe.

  This embodiment solves the above-described problems, and an object thereof is to provide a triple-pipe structure and a heat exchanger that can improve the heat transfer effect between the media and can be reduced in size.

  In order to solve the above-mentioned problem, the triple-pipe structure of the embodiment has three pipes fitted together so as to overlap each other, and has an outer pipe, an intermediate pipe, and an inner pipe from the outside in the overlapping order, The intermediate pipe is formed in a waveform in which crests and troughs are alternately arranged in the circumferential direction of the intermediate pipe, the crests are formed so as to contact the outer pipe, and the troughs are in contact with the inner pipe It is formed as follows.

  Since the intermediate tube is formed in a corrugated shape, the area in which the intermediate tube contacts the medium in the inner tube and the outer tube is widened, so that the heat transfer effect between the media is improved and the triple tube can be reduced in size. Further, since the intermediate tube is formed in a corrugated shape, the cross-sectional area and the secondary moment of the triple tube are increased, and the elastic modulus, bending rigidity and torsional rigidity can be increased.

It is a front view of the triple pipe which concerns on 1st Embodiment. It is a partial expanded sectional view of a triple pipe. It is the sectional view on the AA line of FIG. It is sectional drawing of the triple tube which concerns on 2nd Embodiment. It is sectional drawing of the triple tube which concerns on the modification of 2nd Embodiment.

[First Embodiment]
The structure of the triple tube according to the first embodiment of the present invention will be described with reference to FIGS. Here, the triple-pipe structure refers to a structure in which three or more pipes adjacent to each other in the overlapping direction are combined in a structure in which three or more pipes are fitted to each other.

  FIG. 1 is a front view of a triple tube. As shown in FIG. 1, the triple tube structure in which three tubes are fitted together so as to overlap each other has an outer tube 10, an intermediate tube 20, and an inner tube 30 from the outside in the overlapping order. The triple pipe structure is used for a heat exchanger such as a water heater and an air conditioner in which heat is exchanged by a medium, in addition to being used for a heat exchanger for heating water in a bathtub.

  Any medium of gas, liquid, and solid enters the outer tube 10, the intermediate tube 20, and the inner tube 30. It depends on the application of the heat exchanger what kind of medium enters. There are also media that change from gas to liquid and vice versa, depending on the temperature or pressure in the tube.

  In the heat exchange, the heat of the high-temperature medium is moved to the low-temperature medium, so that the heat is taken away from the high-temperature medium to lower the temperature, and the low-temperature medium is heated to raise the temperature.

  Next, an example of the structure of the triple tube used for the heat exchanger will be described with reference to FIGS. FIG. 2 is a partially enlarged sectional view of the triple tube. As shown in FIG. 2, the outer tube 10 is a hollow shaft, and both end portions 11 of the outer tube 10 are reduced in diameter and are in close contact with both end portions 21 of the intermediate tube 20. A connecting tube 12 is provided at the upstream end 11 of the outer tube 10, and a connecting tube 13 is provided at the downstream end 11. For example, T1 [° C.] medium (warm water) A flows into the outer tube 10 from the connecting tube 12 and flows out from the connecting tube 13.

  The intermediate tube 20 is hollow, and both end portions 21 of the intermediate tube 20 are reduced in diameter and are in close contact with both end portions 31 of the inner tube 30. A connecting pipe 22 is provided at the upstream end 21 of the intermediate pipe 20, and a connecting pipe 23 is provided at the downstream end 21. For example, a medium (tap water) B of T2 (<T1) [° C.] flows into the intermediate pipe 20 from the connecting pipe 21 and flows out from the connecting pipe 23.

  3 is a cross-sectional view taken along line AA of FIG. As shown in FIG. 3, the intermediate tube 20 is formed in a waveform by alternately arranging peaks 25 and valleys 26 in the waveform in the circumferential direction of the intermediate tube 20. The crests 25 and the troughs 26 are the same number, and two or more are provided at equal intervals in the circumferential direction of the intermediate tube 20. The number of peaks 25 and valleys is preferably 4 to 6 (5 in this embodiment). The ridges 25 are formed so as to be in contact with each other at five locations at equal intervals in the circumferential direction of the outer tube 10 by projecting the peripheral wall 27 of the intermediate tube 20 outward. The trough portions 26 are formed so as to be in contact at five locations at equal intervals in the circumferential direction of the inner tube 30 by denting the peripheral wall 27 of the intermediate tube 20 inward. Since the peak portion 25 of the intermediate tube 20 is in contact with the outer tube 10, the medium A in the outer tube 10 flows through the valley portion 26 between the adjacent peak portions 25.

  Since the peak portion 25 is in contact with the outer tube 10 and the valley portion 26 is in contact with the inner tube 30, its rigidity is increased as compared with the triple tube in which the outer tube 10, the intermediate tube 20 and the inner tube 30 are simply fitted together. Is possible. Further, it is possible to prevent the generation of abnormal noise due to vibration transmitted from outside the triple tube or vibration generated inside the triple tube.

  The number of peaks 25 and valleys 26 is preferably 2 to 15. However, the larger the number, the higher the heat transfer effect during heat exchange, and the higher the bending rigidity and torsional rigidity. The reason why the bending rigidity and torsional rigidity are increased will be described later.

  The intermediate tube 20 is formed to be twisted around the axis 28 of the intermediate tube 20. By twisting the intermediate tube 20 around the axis 28, the crests 25 and the troughs 26 are spirally curved.

  Since the peak portion 25 and the valley portion 26 are spirally curved, the flow of the medium B is also curved. At this time, the medium B flows so as to gather in a region outside the curve (outside the valley portion 26), so that turbulence is likely to occur in the medium B in a region inside the curve (inside the valley portion 26). The twisting angle (twisting angle) of the intermediate tube 20 may be any angle as long as it is between the range in which the turbulent flow of the medium is generated and the angle that hinders the flow. An example of the twist angle of the intermediate tube 20 is preferably 2 to 45 degrees. Here, the twist angle is an angle formed by a spiral at the top of the peak portion 25 or the bottom of the valley portion and a straight line parallel to the axis 28 passing through a point on the top.

  For example, if the medium A is T1 [° C.] hot water and the medium B is T2 (<T1) [° C.] tap water, the heat of the medium A moves to the intermediate pipe 20, Heat is transferred to medium B. In this way, the heat exchange between the intermediate tube 20 and the medium B is performed. However, since the flow of the medium B is turbulent, heat transfer is actively performed in the medium. Therefore, the medium B can be effectively heated by the heat of the medium A, particularly through the inside of the intermediate tube 20, and the heat transfer effect can be improved.

  Next, an example of a method for manufacturing a triple tube will be described.

  As a material of the outer tube 10, the intermediate tube 20, and the inner tube 30 constituting the triple tube, for example, a metal made of a metal having high thermal conductivity such as copper, aluminum, brass, tungsten steel, chromium steel, manganese steel, carbon steel, etc. A tube is used.

  The diameter and thickness of the metal tube varies depending on the application of the heat exchanger. As an example, a metal tube having a diameter of about 20 [mm] is used for the outer tube 10, a diameter of about 30 [mm] is used for the intermediate tube 20, and a metal tube of about 10 [mm] is used for the inner tube 30. In addition, the thickness of each metal tube is 0.5 [mm] to 1.2 [mm].

  As an example of a manufacturing method of each pipe, a drawing process is used in which a metal pipe is drawn through a tapered hole formed by a die (die) so as to have a predetermined cross-sectional shape.

  The triple-pipe structure described above is used, for example, in a heat exchanger and as a building material.

  Next, the operation when the triple tube structure is used in a heat exchanger will be described.

  The temperature of the medium A in the outer tube 10, the medium B in the intermediate tube 20, and the medium C in the inner tube 30 is determined depending on the use of the heat exchanger. For example, by flowing a medium A of 60 [° C.] through the outer pipe 10, the medium B of 15 [° C.] in the intermediate pipe 20 is heated to 40 [° C.] and used as hot water for the bath, and the inner pipe 30 Among them, the medium C of 15 [° C.] can be heated to 30 [° C.] and used as hot water in the kitchen. The medium A and the medium B exchange heat by contacting through the peripheral wall 27 of the intermediate tube 20, and the medium B and medium C exchange heat by contacting through the peripheral wall 27 of the inner tube 30. In order to effectively perform heat exchange, it is necessary to increase the contact area between the medium and the peripheral wall 27 and to increase the contact time.

  In order to lengthen the peripheral wall 27 without increasing the outer diameter of the outer tube 10, a peak portion 25 and a valley portion 26 are provided in the intermediate tube 20. Thereby, even if the peripheral wall 27 is long, by providing the peak portion 25 and the valley portion 26, the flow path can be secured and the area where the medium and the intermediate tube 20 contact can be widened. Furthermore, heat is transmitted by heat conduction by bringing the peak portion 25 into contact with the outer tube 10, and heat exchange between the medium A and the medium B can be performed effectively. Further, by bringing the valley portion 26 into contact with the inner tube 30, heat is easily transmitted, and heat exchange between the medium B and the medium C can be performed effectively.

  Furthermore, by forming the peak portions 25 and the valley portions 26 so as to be spirally curved, it is easy to generate turbulent flow in the medium flow inside and outside the intermediate tube. Due to the turbulent flow of the medium, the heat transfer of the medium is actively performed inside and outside the intermediate tube, and the heat exchange between the medium A and the medium B can be effectively performed.

  In addition, depending on the application of the heat exchanger, it is determined how to flow the media A, B, and C. That is, when the flow directions of the media A, B, and C are all the same, the flow direction of any one of the media A, B, and C and the flow direction of the other two media are reversed. There is.

  As shown by arrows in FIG. 2, when the flow direction of the media is reversed, the temperature difference between the media at the start point and the end point of the interval increases in the interval, so the amount of heat exchange is large. Become. Further, the temperatures of the media can be reversed (the temperature T1 of the medium A and the temperature T2 (<T1) of the medium B are reversed at the outlet, T1 <T2).

  When the flow directions of the media are the same, in the section flowing in parallel, the amount of heat exchange decreases from the start point to the end point of the section, and the temperature difference between the media decreases at the end point.

  Next, the case where the triple tube structure is used as a building material will be described.

  The cross-sectional second moment of the triple pipe is increased by providing the peak part 25 and the valley part 26 in the intermediate pipe 20 as compared with the case where the three pipes are simply fitted together, so that the bending rigidity and the torsional rigidity can be increased. It becomes possible.

  In addition, when an external force is applied to the triple pipe in the direction of the axis 28 of the intermediate pipe 20 by bringing the peak 25 into contact with the outer pipe 10 and the valley 26 in contact with the inner pipe 30, Since a frictional force is generated at the contacted portion, it is possible to counteract the external force with a sufficient force.

  Further, the plurality of peak portions 25 are brought into contact with the outer tube 10 at equal intervals, and the plurality of valley portions 26 are brought into contact with the inner tube 30 at equal intervals, thereby compressing the compressive force with respect to the triple tube. Even when acting in a direction perpendicular to 28, it is possible to counteract with a sufficient force.

  Moreover, since the cross-sectional area of the triple pipe is increased by providing the peak part 25 and the valley part 26 in the intermediate pipe 20, the elastic modulus can be increased. Thereby, a triple tube capable of sufficiently resisting a large compressive force or tensile force in the direction of the shaft 28 is obtained.

[Second Embodiment]
Next, a triple tube structure according to a second embodiment of the present invention will be described with reference to FIG.

  In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  FIG. 4 is a cross-sectional view of the triple tube. As shown in FIG. 4, the inner tube 30 has a convex portion 35 formed so as to enter between adjacent valley portions 26 of the intermediate tube 20. The number of the convex portions 35 is the same as that of the valley portions 26 (also called the mountain portions 25), and two or more convex portions 35 are provided at equal intervals in the circumferential direction of the inner tube 30. The number of the convex portions 35 is preferably 4 to 6. Note that the number of convex portions 35 is the same as the number of peak portions 25 and trough portions 26, and in this embodiment, five.

  The amount S that the convex portion 35 enters between the valley portions 26 is 1/10 to 1/1 of the depth of the valley portion 26.

  By providing the convex portion 35 on the inner tube 30, the peripheral wall 37 of the inner tube 30 becomes longer, and the area where the media B and C are in contact with each other through the wall portion of the inner tube 30 can be increased. Thereby, heat exchange between the media B and C can be performed efficiently.

  Next, a modification of the triple tube will be described with reference to FIG.

  FIG. 5 is a cross-sectional view in which the triple tube according to the modification is broken in a direction perpendicular to the axis. As shown in FIG. 5, the inner tube 30 is formed to be twisted around the axis 38 of the inner tube 30. Further, the intermediate tube 20 and the inner tube 30 are twisted in opposite directions. For example, in FIG. 5, the intermediate tube 20 is twisted clockwise while the inner tube 20 is twisted counterclockwise. The twist angle of the inner tube 30 is preferably in the range of an angle that hinders the flow from the angle at which turbulent flow occurs in the flow (for example, 2 to 45 degrees). Here, like the torsion angle of the intermediate tube 20, the torsion angle is an angle formed by a spiral at the top of the convex portion 35 and a straight line parallel to the axis 38 passing through one point thereon.

  A recess 36 that is recessed toward the shaft 38 of the inner tube 30 is formed between the adjacent protrusions 35.

  By forming the inner tube 30 to be twisted, the convex portion 35 and the concave portion 36 are formed to be curved in a spiral shape. Thereby, it becomes easy to generate turbulent flow in the flow on the surface in contact with the inner tube in the intermediate tube 20. As a result, heat transfer in the medium B is actively performed, heat exchange between the media B and C is actively performed, and the heat transfer effect between the media B and C can be improved. It becomes.

  Further, the medium C in the inner tube 30 flows along the convex portion 35 and gathers outside the curve, so that turbulent flow is likely to occur inside the tube. The heat transfer of the medium C is actively performed by the turbulent flow of the medium C, and the heat transfer effect between the mediums B and C can be improved.

  In the above embodiment, different media A, B, and C are allowed to flow through the outer tube 10, the intermediate tube 20, and the inner tube 30, respectively. However, any one of the media A, B, and C is used depending on the application of the heat exchanger. The two may be the same medium. For example, the same medium may flow by connecting the outer tube 10 and the inner tube 30 directly or indirectly. Further, although the media A, B, and C are liquids, they may be gases or solids.

  The embodiment described above is presented as an example, and is not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, rewrites, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 Outer pipe 11 End part 12 Connection pipe 13 Connection pipe 20 Intermediate pipe 21 End part 22 Connection pipe 23 Connection pipe 25 Mountain part 26 Valley part 27 Peripheral wall 28 Axis 30 Inner pipe 31 End part 35 Convex part 36 Concave part 37 Peripheral wall 38 Axis

Claims (7)

In a triple tube structure in which three tubes are fitted to overlap each other and have an outer tube, an intermediate tube, and an inner tube from the outside in the overlapping order,
The intermediate pipe is formed in a waveform in which peaks and valleys are alternately arranged in the circumferential direction of the intermediate pipe,
The peak is formed so as to contact the outer tube,
The triple tube structure is characterized in that the valley portion is formed in contact with the inner tube.   The triple pipe structure according to claim 1, wherein the intermediate pipe is formed to be twisted around an axis of the intermediate pipe.   The triple pipe structure according to claim 2, wherein the inner pipe has a convex portion formed so as to enter between the adjacent valley portions.   The triple pipe structure according to claim 3, wherein the inner pipe is formed so as to be twisted around an axis of the inner pipe.   The apparatus according to claim 4, wherein the inner tube is twisted in the opposite direction with respect to the intermediate tube.   4. The apparatus according to claim 3, wherein the number of the crests, the troughs, and the protrusions is the same, and two or more are provided at equal intervals in the circumferential direction of the intermediate tube.   The heat exchanger which has the structure of the triple tube as described in any one of Claims 1-6, and the flow path respectively connected to the said outer tube, the said intermediate tube, and the said inner tube.

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