METHOD OF MANUFACTURING HEAT EXCHANGER PIPE

Abstract

The present invention relates to a heat exchanger pipe enabling heat exchange between fluid flowing through the pipe and fluid existing outside the pipe, and a method of manufacturing the heat exchanger pipe. In particular, the present invention relates to a heat exchanger pipe that improves a heat exchange rate by making flow of fluid through the pipe more active and increasing a contact amount, that has an improved contact characteristic and a sealing characteristic between an outer pipe and an insert inserted in the outer pipe in the process of manufacturing, and that is easily manufactured; and a method of manufacturing the heat exchanger pipe.

Claims

1. A method of manufacturing a heat exchanger pipe comprising an outer pipe formed in a cylindrical shape and a first half shell and a second half shell each having a semi-cylinder shape, the method comprising: an insert preparation process of placing the first half shell and the second half shell on ends on an upper bed having the same diameter as the first half shell and the second half shell combined to face each other; an outer pipe preparation process of placing the outer pipe on end on a lower bed having a larger diameter than the upper bed and supporting a bottom of the upper bed such that the first half shell and the second half shell are inserted in the outer pipe; a pressing-preparation process of disposing a dice mold having a tapered portion at a lower portion therein and having a pressing portion over the tapered portion therein-a diameter of a lower end of the tapered portion is the same as an outer diameter of the outer pipe and a diameter of the pressing portion is the same as a diameter of an assembly of the first half shell and the second half shell-over the outer pipe; and a pressing process of pressing the outer pipe with the pressing portion such that the inner circumferential surface of the outer pipe comes in close contact with the outer circumferential surfaces of the first half shell and the second half shell by moving down the dice mold such that the outer pipe is fitted in the dice mold and then by further moving down the dice mold.

2. A method of manufacturing the heat exchanger pipe of claim 1, a first bending portions and a second bending portions for assembly are respectively formed at both end portions of the first half shell and at both end portions of the second half shell.

3. A method of manufacturing the heat exchanger pipe of claim 2, both ends of the first half shell and both ends of the second half shell are formed in flat shapes.

4. A method of manufacturing the heat exchanger pipe of claim 3, wherein the first bending portions bending toward the outer pipe are formed with a predetermined length from the flat ends of the first half shell and the second bending portions bending toward the outer pipe are formed with a predetermined length from the flat ends of the second half shell.

5. A method of manufacturing the heat exchanger pipe of claim 4, when the outer pipe is pressed and compressed to come in close contact with the outer circumferential surfaces of the first half shell and the second half shell in the assembling process, the first bending portions and the second bending portion are pressed and unfolded inward and the flat ends of the first half shell and the flat ends of the second half shell are slightly pressed and deformed, whereby the ends are strongly brought in surface contact with each other.

6. A method of manufacturing the heat exchanger pipe of claim 1, a heat exchanger fins are disposed on a line extending from one side to the other side of the inner circumferential surface of a heat exchanger tube and are spaced in a direction of an apsidal line of the heat exchanger tube.

7. A method of manufacturing the heat exchanger pipe of claim 6, some of heat exchanger fins are discontinuous type heat exchanger fins that are disconnected at middle portions in a longitudinal direction thereof and the others except for the discontinuous type heat exchanger fins are continuous type heat exchanger fins that are entirely continuous in a longitudinal direction thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] FIG. 1 is a cross-sectional view showing a heat exchanger pipe (heat exchanger tube) according to the related art;

[0043] FIG. 2 is a front cross-sectional view showing a hot water storage type boiler according to the related art;

[0044] FIG. 3 is a view showing the hot water storage type boiler according to the related art;

[0045] FIG. 4 is a perspective view showing a heat exchanger pipe according to a first embodiment of the present invention;

[0046] FIG. 5 is a cross-sectional view showing the heat exchanger pipe according to a first embodiment of the present invention;

[0047] FIG. 6 is a cross-sectional view showing a heat exchanger pipe according to a second embodiment of the present invention;

[0048] FIGS. 7A and 7B are cross-sectional views showing a heat exchanger pipe according to a third embodiment of the present invention;

[0049] FIG. 8 is a partial cross-sectional view showing a heat exchanger pipe according to a fourth embodiment of the present invention;

[0050] FIG. 9 is a perspective view showing a heat exchanger pipe according to a fourth embodiment of the present invention;

[0051] FIG. 10 is a perspective view showing a heat exchanger pipe according to a sixth embodiment of the present invention;

[0052] FIGS. 11A to 11E are views showing a method of manufacturing the heat exchanger pipe according to the first embodiment of the present invention;

[0053] FIG. 12 is a perspective view showing a heat exchanger pipe according to a seventh embodiment of the present invention;

[0054] FIGS. 13A and 13B are front views showing a heat exchanger fin formed by integrally connecting two half shells for the heat exchanger pipe according to the seventh embodiment of the present invention;

[0055] FIGS. 14A to 14E are views showing a method of manufacturing the heat exchanger pipe according to the seventh embodiment of the present invention;

[0056] FIG. 15 is a perspective view showing an elliptical heat exchanger pipe according to an eighth embodiment of the present invention;

[0057] FIGS. 16A to 16C are plan views showing the elliptical heat exchanger pipe according to the eighth embodiment of the present invention and an another-shaped heat exchanger pipe;

[0058] FIGS. 17A and 17B are plan views showing other examples of the heat exchanger pipe according to the eighth embodiment of the present invention;

[0059] FIG. 18 is a perspective view showing a hot water storage type heat exchanger having the elliptical heat exchanger pipe according to the eighth embodiment of the present invention;

[0060] FIG. 19 is a plan view showing the hot water storage type heat exchanger having the elliptical heat exchanger pipe according to the eighth embodiment of the present invention; and

[0061] FIG. 20 is a front view showing the hot water storage type heat exchanger having the elliptical heat exchanger pipe according to the eighth embodiment of the present invention;

DETAILED DESCRIPTION OF THE INVENTION

[0062] Hereafter, a heat exchanger pipe according to embodiments of the present invention and a method of manufacturing the heat exchanger pipe are described in detail with reference to the accompanying drawings.

[0063] FIG. 4 is a perspective view showing a heat exchanger pipe according to a first embodiment of the present invention and FIG. 5 is a cross-sectional view showing the heat exchanger pipe according to a first embodiment of the present invention.

[0064] First, a heat exchanger pipe 20 according to a first embodiment of the present invention, as shown in the perspective view of FIG. 4 and the cross-sectional view of FIG. 5, includes an outer pipe 21 formed in a cylindrical shape, a first half insert 22, 23 and a second half insert 24, 25 that are inserted in the outer pipe 21. For example, the outer pipe 21 may be made of a metal material such as steel, and the first half insert 22, 23 and the second half insert 24, 24 may be made of an aluminum material.

[0065] The first half insert 22, 23 is composed of a first half shell 22 formed in a semi-cylinder shape obtained by longitudinally cutting a cylinder, and a plurality of first ribs 23 disposed in the first half shell 22 and having long fin shapes. Similarly, the second half insert 24, 25 is composed of a second half shell 24 and a plurality of second ribs 25.

[0066] Ends F of the first half shell 22 and ends F′ of the second half shell 24 are flat surfaces, so when the first half shell 22 and the second half shell 24 are disposed to face each other and assembled such that the ends are strongly brought in surface contact with each other, fluid flowing through the first half shell 22 and the second half shell 24 is prevented from leaking through gaps between the first half shell 22 and the second half shell 24.

[0067] The first ribs 23 spaced a predetermined gap from each other extend toward the inner space from the inner circumferential surface of the first half shell 22 and the second ribs 25 spaced a predetermined gap from each other extend toward the inner space from the inner circumferential surface of the second half shell 24. The first ribs 23 and the second ribs 25 are arranged perpendicular to a virtual interface that separates the first half shell 22 and the second half shell 24.

[0068] In particular, the lengths of the first ribs 23 and the second ribs 25 are adjusted to each make an S-shape when the ends of the first ribs 23 and the ends of the second ribs 25 are sequentially connected by virtual lines, respectively, and the facing ends of the first ribs 23 and the second ribs 25 are spaced not to be in contact with each other.

[0069] For example, the first ribs 23 include first-first rib 23a to sixth-first rib 23f sequentially from the left in the figure, in which the second-second rib 25b is longer than the first-first rib 23a and the third-first rib 23c is shorter than the second-first rib 23b.

[0070] Further, the fourth-first rib 23d is longer than the third-first rib 23c, the fifth-first rib 23e is shorter than the fourth-first rib 23d, and the sixth-first rib 23f is shorter than the fifth-first rib 23e, that is, the lengths of the ribs are adjusted in this way.

[0071] Therefore, when the ends from the first-first rib 23a to the sixth-first rib 23f are sequentially connected by a virtual line, two S-shapes overlapping each other appear (indicated by dotted lines in FIG. 5).

[0072] The second ribs 25 also include six ribs, similar to the first ribs 23, in which when the ends from the first- to sixth-second ribs 25 are sequentially connected, two S-shapes overlapping each other appears. The first ribs 23 and the second ribs 25 are spaced not to be in contact with each other.

[0073] Accordingly, as compared with a heat exchanger tube of the related art in which flow of fluid in the tube is monotonous because the ends of ribs (see 1005 in FIG. 5) are aligned to form a comb shape, the present invention further have an S-shaped passage, so the fluid flowing through the first half shell 22 and the second half shell 24 fluctuates much, whereby the thermal contact amount between the fluid and the first ribs 23 or the second ribs 25 increases.

[0074] Further, the thermal contact amount of fluid, which is a heat source such as high-temperature combustion gas, with the first ribs 23 or the second ribs 25 increases, the amount of heat transferring to the outer pipe 21 being in contact with the first half shell 22 and the second half shell 24 also increases, whereby it is possible to increase the heat exchange efficiency with raw water, etc. outside the outer pipe 21 can be increased. However, the first half insert 22, 23 is formed by integrally extruding the first half shell 22 and the first rib 23 and the second half insert 24, 25 is formed by integrally extruding the second half shell 24 and the second ribs 25, and in this case, if the same mold is used regardless of the first half insert 22, 23 and the second half insert 24, 25, it would be possible to reduce the manufacturing cost.

[0075] Obviously, in this case, the first half insert 22, 23 and the second half insert 24, 25 should be assembled such that the cross-sectional shapes are symmetric left and right.

[0076] Hereafter, a heat exchanger pipe according to a second embodiment of the present invention is described with reference to the accompanying drawings.

[0077] FIG. 6 is a cross-sectional view showing a heat exchanger pipe according to a second embodiment of the present invention.

[0078] As shown in FIG. 6, a heat exchanger pipe 30 according to a second embodiment of the present invention includes an outer pipe 31 formed in a cylindrical shape, and a first half insert 32, 33 and a second half insert 34, 35 that are inserted in the outer pipe 31.

[0079] The first half insert 32, 33 is composed of a first half shell 32 and a plurality of first ribs 33 and the second half insert 34, 35 is composed of a second half shell 34 and a plurality of second ribs 35. This configuration is the same as that of the first embodiment of the present invention described above.

[0080] However, in the heat exchanger pipe according to the second embodiment of the present invention, the first ribs 33 include a first-first rib 33a to a fifth-first rib 33e sequentially from the left in the figure and the second ribs 35 also include five ribs. When the ends of the five first ribs 33 are sequentially connected by a virtual line, one S-shape is obtained and, similarly, another S-shape is obtained from the second ribs 35.

[0081] That is, the ribs of the first embodiment of the present invention described with reference to FIG. 5 each include six ribs (see 23 and 25 in FIG. 5), while the ribs of the second embodiment of the present invention each include five ribs 33 and 35, that is, the numbers of ribs are different, so the S-shapes may be slightly changed, but the present invention can increase the heat exchange rate by increasing flow of fluid.

[0082] Hereafter, a heat exchanger pipe according to a third embodiment of the present invention is described with reference to the accompanying drawings. However, the third embodiment of the present invention is fundamentally based on the first embodiment of the present invention, so only different configurations are shown and described.

[0083] FIGS. 7A and 7B are cross-sectional views showing a heat exchanger pipe according to a third embodiment of the present invention.

[0084] As shown in FIGS. 7A and 7B, a heat exchanger pipe according to a third embodiment of the present invention includes a first half insert 22, 23 and a second half insert 24, 25 that are inserted in an outer pipe (see 21 in FIG. 2) formed in a cylindrical shape. The first half insert 22, 23 is composed of a first half shell 22 and a plurality of first ribs 23 and the second half insert 24, 25 is composed of a second half shell 24 and a plurality of second ribs 25. This configuration is the same as that of the first embodiment of the present invention described above.

[0085] However, the third embodiment of the present invention has a different in that first bending portions 22a and second bending portions 24a for assembly are respectively formed at both end portions of the first half shell 22 and at both end portions of the second half shell 24, and the first bending portions 22a and the second bending portions 24a are bent outward respectively from first bending surfaces 22a′ and second bending surfaces 24a′.

[0086] That is, both ends of the first half shell 22 and both ends of the second half shell 24 are formed in flat shapes, in which, as shown in FIG. 7A, the first bending portions 22a bending toward the outer pipe 31 are formed with a predetermined length from the flat ends of the first half shell 22 and the second bending portions 24a bending toward the outer pipe 31 are formed with a predetermined length from the flat ends of the second half shell 24.

[0087] Accordingly, as shown in FIG. 7B, when the outer pipe 21 is pressed and compressed to come in close contact with the outer circumferential surfaces of the first half shell 22 and the second half shell 24 in the assembling process, the first bending portions 22a and the second bending portion 24a are pressed and unfolded inward and the flat ends of the first half shell 22 and the flat ends of the second half shell 24 are slightly pressed and deformed, whereby the ends are strongly brought in surface contact with each other.

[0088] Therefore, it is possible to solve the problem in the related art that the force that is actually applied for assembly acts perpendicular to the outer circumferential surface of the outer tube 1001 in the related art but the force for strongly bring the groove-shaped recesses 1007 and the rib-shaped protrusions 1008 in close contact with is not actually applied in the direction of the above force, thereby causing gaps between the groove-shaped recesses 1007 and the rib-shaped protrusions 1008.

[0089] FIG. 8 is a partial cross-sectional view showing a heat exchanger pipe according to a fourth embodiment of the present invention.

[0090] Referring to FIG. 8, in a fourth embodiment of the present invention, a plurality of first prominences and recessions 22b is formed on flat ends of the first half shell 22 and a plurality of second prominences and recessions (not shown) is formed on flat ends of the second half shell 24, so the first prominences and recessions 22b and the second prominences and recessions are fitted to each other when the entire outer pipe 21 is uniformly pressed for assembly, thereby being able to further increase the sealing force.

[0091] Obviously, a cut groove 22c is formed on the bending surfaces of the first bending portions 22a and the bending surfaces of the second bending portions 24a, so when the entire outer pipe 21 is pressed for assembly, the first bending portions 22a and the second bending portions 24a are guided to be unfolded, whereby assembly can be achieved more easily.

[0092] Hereafter, a heat exchanger pipe according to a fifth embodiment of the present invention is described with reference to the accompanying drawings.

[0093] FIG. 9 is a perspective view showing a heat exchanger pipe according to a fourth embodiment of the present invention.

[0094] As shown in FIG. 9, a heat exchanger pipe according to a fifth embodiment of the present invention includes an outer pipe 41, and, as described above, an insert 42 composed of a first half insert and a second half insert. This configuration is the same as the above description.

[0095] However, in the fifth embodiment of the present invention, heat exchange grooves 41a for increase the surface area is formed on the surface of the outer pipe 41, so the heat of fluid (i.e., high-temperature combustion gas, etc.) flowing through the outer pipe 41 can more efficiently transfer to fluid (i.e., raw water, etc.) existing outside the outer pipe 41.

[0096] However, it is exemplified that a plurality of heat exchange grooves is longitudinally formed on the outer pipe 41 and arranged around the outer pipe 41 in FIG. 9, but the heat exchange grooves circularly arranged around the outer pipe 41 may be longitudinally arranged with predetermined gaps on the outer pipe 41 or may be spirally formed on the outer circumferential surface of the outer pipe, and other various patterns may be possible. Hereafter, a heat exchanger pipe according to a sixth embodiment of the present invention is described with reference to the accompanying drawings.

[0097] FIG. 10 is a perspective view showing a heat exchanger pipe according to a sixth embodiment of the present invention. As shown in FIG. 10, a heat exchanger pipe 50 according to a sixth embodiment of the present invention includes an outer pipe 51, and, as described above, an insert 52 composed of a first half insert and a second half insert.

[0098] In particular, a locking protrusion 51a protruding inward where the insert 52 is inserted is formed at both end portions of the outer pipe 51, that is, the locking protrusions 51 are formed at portions corresponding to both longitudinal ends of the insert 52 on the outer pipe 51.

[0099] Accordingly, the insert 52 is firmly fixed without moving toward an end or the other end of the open outer pipe 51, so after the outer pipe 51 and the insert 52 are assembled by pressing the entire outer pipe 51 such that the inner circumferential surface of the outer pipe 51 and the outer circumferential surface of the insert 52 are brought in contact with each other, separation of the insert 51 from the external pipe 51 is prevented.

[0100] Hereafter, methods of manufacturing the heat exchanger pipes according to the above embodiments of the present invention are described hereafter.

[0101] FIGS. 11A to 11E are views showing a method of manufacturing the heat exchanger pipe according to the first embodiment of the present invention.

[0102] A method of manufacturing the heat exchanger pipe according to the first embodiment of the present invention described with reference to FIG. 4 is exemplified hereafter. First, as shown in FIG. 11A, a bed T, T′ is prepared to manufacture a heat exchanger pipe according to the present invention. The bed T, T′ is composed of a lower bed T and an upper bed T′ fixed on the lower bed T.

[0103] The upper bed T′ has a size that is the same as the diameter of the assembly of the first half shell 22 and the second half shell 24, so the first half shell 22 and the second half shell 24 can be stably placed thereon. Further, the lower bed T is larger in diameter than the upper bed T′, so the outer pipe 21 can be placed thereon.

[0104] Next, as shown in FIG. 11B, the first shell 22 and the second half shell 24 combined to face each other are placed on ends on the upper bed T′. That is, the first half insert 22, 23 and the second half insert 24, 25 are prepared (insert preparation step).

[0105] Next, as shown in FIG. 11C, a prototypal outer pipe 21′ is placed on end on the lower bed such that the first half shell 22 and the second half shell 24 are positioned inside the outer pipe 21′ (outer pipe preparation step). The prototypal outer pipe 21′ not machined yet is larger in diameter than the assembly of the first half shell 22 and the second half shell 24, so the outer pipe can be fitted over the first half shell 22 and the second half shell 24 from above.

[0106] Next, as shown in FIG. 11D, a dice mold D having a tapered portion, which gradually decreases in width upward, at a lower portion therein, having a pressing portion over the tapered portion therein is prepared over the outer pipe 21 (pressing-preparation step), in which the diameter of the lower end of the tapered portion is the same as (or may be slightly larger than) the outer diameter of the outer pipe 21 and the diameter of the pressing portion is the same as (or may be slightly smaller than) the diameter of the assembly of the first half shell 22 and the second half shell 24.

[0107] Next, as shown in FIG. 11E, the dice mold D is moved down such that the prototypal outer pipe 21′ is inserted into the dice mold D, and in this state, the dice mold D is further moved down such that the pressing portion presses the prototypal outer pipe 21′, whereby the inner circumferential surface of the outer pipe 21 obtained by compression of the prototypal outer pipe 21′ is pressed to come in close contact with the outer surfaces of the first half shell 22 and the second half shell 24 (pressing step). Accordingly, it is possible to conveniently and simply manufacture a heat exchanger pipe.

[0108] Hereafter, a heat exchanger pipe according to a seventh embodiment of the present invention is generally described with reference to the accompanying drawings.

[0109] FIG. 12 is a perspective view showing a heat exchanger pipe according to a seventh embodiment of the present invention.

[0110] As shown in FIG. 12, a heat exchanger pipe according to the present invention includes an outer pipe P formed in a cylindrical shape and a heat exchanger fin 20 formed by integrally connecting two half shells inserted in the outer pipe P (hereafter, referred to as a ‘heat exchanger fin’).

[0111] The heat exchanger fin 20 and the outer pipe P are assembled such that the outer circumferential surface of the heat exchanger fin 20 and the inner surface of the outer pipe P are completely in close contact with each other. The outer pipe P is made of a metal material such as steel and the heat exchanger fin 20 is made of a metal material such as aluminum. Accordingly, heat is exchanged between first fluid flowing through the heat exchanger fin 20 and second fluid flowing on the surface of the outer pipe P.

[0112] For example, when high-temperature combustion gas produced by burning fuel with a burner (not shown) flows through the heat exchanger fin 20 and low-temperature raw water comes in contact with the surface of the outer pipe P, heat exchange occurs between the high-temperature combustion gas and the raw water. The heated raw water is used as hot water, heating water, or the like.

[0113] In the entire length of the outer pipe, a locking protrusion G protruding inward is formed at portions corresponding to both longitudinal end of the heat exchanger fin 20. Accordingly, separation of the heat exchanging fin 20 from the outer pipe P is separated. This is for preventing separation of the heat exchanger fin 20 due to vibration of its own weight in long-time use.

[0114] FIGS. 13A and 13B are front views showing a heat exchanger fin formed by integrally connecting two half shells for the heat exchanger pipe according to the seventh embodiment of the present invention.

[0115] As shown in FIGS. 12, 13A, and 13B, the heat exchanger fin 20 according to the present invention includes a first half shell 21 and a second half shell 22 integrally connected to the first half shell 21. First ribs 21a are formed on the inner circumferential surface of the first half shell 21 and second ribs 22a are formed on the inner circumferential surface of the second half shell 22.

[0116] The first ribs 21a are integrally formed on the inner circumferential surface of the first half shell 21 and the second ribs 22a are integrally formed on the inner circumferential surface of the second half shell 22. In particular, the first half shell 21 and the second half shell 22 are integrally formed with first ends thereof are connected to each other. As a forming method, extrusion is usually used.

[0117] The first half shell 21 and the second half shell 22 function as a body, and the first ribs 21a and the second ribs 22a are used for the purpose of increasing the heat exchange rate by increasing the surface area. In terms of the purpose, a plurality of prominences and recession is formed on the surfaces of the first ribs 21a and the second ribs 22a, thereby further increasing the surface area.

[0118] As shown in FIG. 13A, the first half shell 21 and the second half shell 22 are each formed in a semi-cylinder shape obtained by longitudinally cutting a cylinder. First ends in the circumferential direction of the first half shell 21 and the second half shell 22 are connected to each other. That is, the first half shell 21 and the second half shell 22 are integrally connected through a bridge 23.

[0119] Accordingly, as shown in FIG. 13B, when the first half shell 21 and the second half shell 22 are pivoted toward each other on the bridge 23, a cylindrical shape is formed by the first half shell 21 and the second half shell 22. Fluid such as high-temperature combustion gas flows through the cylindrical first half shell 21 and second half shell 22.

[0120] A first rib 21a extends toward the inner space from the inner circumferential surface of the first half shell 21 and a second rib 22a extends toward the inner space from the inner circumferential surface of the second half shell 22. In this case, pluralities of first ribs 21a and second ribs 22a that have fin shapes are provided to increase the heat exchange rate by increasing the surface area.

[0121] In particular, according to the present invention, a folding groove 32a is formed at the bridge 23 where the first half shell 21 and the second half shell 22 are integrally connected to each other. Accordingly, the first half shell 21 and the second half shell 22 can be easily closed, as shown in FIG. 13B, even in the state in which the first half shell 21 and the second half shell 22 are open away from each other.

[0122] The folding groove 23a, as shown in the figures, is formed in a V-shaped cross-section on the inner side of the bridge 23, so it guides the first half shell 21 and the second half shell 22 such that they can be easily closed when they are coupled to each other, and grooves having other various shapes can be used as long as the half shell can be easily closed.

[0123] It is exemplified in FIGS. 13A and 13B that second ends 21b and 22b (i.e., the ends opposite to the bridge) of the first half shell 21 and the second half shell 22 are flat. However, first prominences and recessions may be formed on the second end 21b of the first half shell 21 and second prominences and recessions may be formed on the second end 22b of the second half shell 22.

[0124] When the first prominences and recessions and the second prominences and recessions are provided, the second ends 21b and 22b of the first half shell 21 and the second half shell 22 are engaged in close contact with each other, thereby considerably reducing leakage of condensate water, etc. produced by condensation of combustion gas. The first ends of the first half shell 21 and the second half shell 22 are integrally connected to each other already in the forming process, leakage of condensate water, etc. is completely prevented.

[0125] Further, according to the present invention, the lengths of the first ribs 21a and the second ribs 22a are adjusted such that when ends of the first ribs 21a and ends of the second ribs 22a are respectively sequentially connected by virtual lines, they respectively form an S-shape. Ends, which face each other, of the first ribs 21a and the second ribs 22a are spaced part from each other not to be in contact with each other Accordingly, flow of fluid is monotonous because ribs of a heat exchanger pipe are arranged in comb shape in the related art, but the present invention further has an S-shaped passage, so fluctuation of fluid increases.

[0126] Further, the thermal contact amount of fluid such as high-temperature combustion gas with the first ribs 21a or the second ribs 22a increases, so the heat transfer amount to the outer pipe P increases. Accordingly, the heat exchange efficiency with raw water, etc. outside the outer pipe P increases.

[0127] As described above, according to the present invention, since the first half shell 21 and the second half shell 22 are connected through the bridge 23 like a single part, it is easy to form the heat exchanger pin 20 itself. This is because it is possible to manufacture the first half shell 21 and the second half shell 22 simultaneously in extrusion.

[0128] In the related art, a first half shell (1003 in FIG. 1) and a second half shell (1004 in FIG. 1) are completely separated from each other, so there is a problem that it is required to cut each of the first half shell 1003 and the second half shell 1004 one time, that is, a total of cutting twice is required. However, according to the present invention, when the heat exchanger fin 20 is manufactured with an appropriate length, it is possible to cut the first half shell 21 and the second half shell 22 simultaneously.

[0129] Further, according to the present invention, since the first half shell 21 and the second half shell 22 are connected to each other, the heat exchanger fin 20 is conveniently inserted into the outer pipe P and productivity is improved. In the related art, as shown in FIG. 1, since the first half shell 21 and the second half shell 22 are separated, it is difficult to insert the half shells into the outer pipe P while holding the half shells. Further, there is problem that the first half shell 21 and the second half shell 22 fall into disorder when they are inserted. Further, according to the present invention, since the first half shell 21 and the second half shell 22 are integrally connected through the bridge 23, condensate water does not leak to the outside at least through the bridge 23. Since condensate water is acidic, it causes environment contamination, etc. when leaking, so it is very important to prevent leakage of condensate water.

[0130] Hereafter, a method of a heat exchanger pipe according to an embodiment is described.

[0131] FIGS. 14A to 14E are views showing a method of manufacturing the heat exchanger pipe according to the seventh embodiment of the present invention.

[0132] First, as shown in FIG. 14A, a bed T, T′ is prepared to manufacture a heat exchanger pipe according to the present invention. The bed T, T′ is composed of a lower bed T and an upper bed T′ fixed on the lower bed T.

[0133] The upper bed T′ has the same size as the diameter of the heat exchanger fin 20 obtained by combining the first half shell 21 and the second half shell 22, so the heat exchanger fin 20 is placed on the upper bed T′, and the outer pipe P is placed on the lower bed T because the lower bed T is larger in diameter than the upper bed T′.

[0134] Next, as shown in FIG. 14B, the heat exchanger fin 20 is placed on the upper bed T′.

[0135] Next, as shown in FIG. 14C, a prototypal outer pipe P′ is placed on end on the lower bed, whereby the heat exchanger fin 20 is disposed in the prototypal outer pipe P′. The prototypal outer pipe P′ not machined yet is larger in diameter than the heat exchanger fin 20, so the prototypal outer pipe P′ can be fitted over the heat exchanger fin 20 from above.

[0136] Next, as shown in FIG. 14D, a dice mold D having a tapered portion, which gradually decreases in width upward, at a lower portion therein, and having a pressing portion over the tapered portion is disposed over the outer pipe P.

[0137] Next, as shown in FIG. 14E, the dice mold D is moved down such that the prototypal outer pipe P′ is fitted in the dice mold D, and then the dice mold D is further moved down, thereby pressing the prototypal outer pipe P′ with the pressing portion.

[0138] Accordingly, the inner circumferential surface of the outer pipe P formed by contraction of the prototypal outer pipe P′ comes in close contact with the outer surface of the heat exchanger fin 20, so the heat exchanger fin 120, P is simply manufactured.

[0139] Hereafter, an elliptical heat exchanger pipe according to an eighth embodiment of the present invention and a hot water storage type heat exchanger having the elliptical heat exchanger pipe are described with reference to the accompanying drawings.

[0140] FIG. 15 is a perspective view showing an elliptical heat exchanger pipe according to an eighth embodiment of the present invention.

[0141] First, an elliptical heat exchanger pipe 240 according to the present invention shown in FIG. 15 is used as a component of various heating/cooling system such as a boiler, a heat pump, and an air conditioner, and has an elliptical cross-section and a predetermined length.

[0142] The elliptical heat exchanger pipe 240 enables heat exchange between fluid flowing therethrough and fluid exiting outside, thereby being able to supply not only hot water or heating water, but also hot air or cold air.

[0143] For example, the fluid flowing through the elliptical heat exchanger pipe 240 is high-temperature combustion gas produced by the burner of a boiler and the fluid existing outside the elliptical heat exchanger pipe 240 is low-temperature liquid such as raw water.

[0144] Accordingly, high-temperature combustion gas exchanges heat with raw water while flowing through the elliptical heat exchanger pipe 240, where by hot water or heating water is supplied to heating loads such as a house, a factory, an office, or the like.

[0145] To this end, the elliptical heat exchanger pipe 240 according to the present invention includes an elliptical heat exchanger tube 241 and a plurality of heat exchanger fins 242 increasing a heat transfer area and a heat exchange rate by protruding toward the empty space inside the heat exchanger tube 241.

[0146] However, a contact shell SH may be further disposed between the heat exchanger tube 241 and the heat exchanger fins 242, and in this case, the heat exchanger fins 242 protrude from the inner surface of the contact shell SH and the outer surface of the contact shell SH is in surface contact with the inner side of the heat exchanger tube 241, whereby heat transfer occurs.

[0147] The heat exchanger fins 242 are formed by drawing a metallic material (e.g., stainless steel), etc. which have high thermal conductivity, as an embodiment, and the contact shell SH may be included in drawing. The heat exchanger fins 242 manufactured in this way are inserted in the heat exchanger tube 241.

[0148] The heat exchanger tube 241 is formed in a tube shape having an elliptical cross-section and having a hollow portion so that a heat source (i.e., fluid) flows through it. A plurality of heat exchanger fins 242 protrude from the inner circumferential surface of the heat exchanger tube 241 and are provided to increase the heat exchange rate.

[0149] The reason of making the heat exchanger tube 241 in an elliptical shape in the present invention is for increasing the amount of flow of heat exchange fluid (e.g., combustion gas) by making the apsidal line of the heat exchanger tube 241 long, in which the length of the apsidal line is appropriately adjusted in accordance with heat exchange capacity.

[0150] Further, by providing a heat exchanger pipe having an elliptical cross-section, it is possible to increase the heat transfer area in comparison to other-shaped heat exchanger pipe having the same size of outer pipe (i.e., tube) and it is possible to prevent coming-off when inserting and pressing heat exchanger fins in the outer pipe.

[0151] In detail, the case of an elliptical heat exchanger pipe, as in the present invention, and the case of other-shaped heat exchanger pipe, that is, a circular or oblong heat exchanger pipe, etc. are compared hereafter.

[0152] FIGS. 16A to 16C are plan views showing the elliptical heat exchanger pipe according to the eighth embodiment of the present invention and an another-shaped heat exchanger pipe.

[0153] FIG. 16A is a plan view showing a common circular heat exchanger pipe having a circular cross-section, FIG. 16B is an elliptical heat exchanger pipe 240 of the present invention, and FIG. 16C is an oblong heat exchanger pipe having an oblong cross-section.

[0154] First, the circular heat exchanger pipe shown in FIG. 16A has a very small radius of curvature, so even if the diameter is physically increased, a large number of heat exchanger fins cannot be efficiently disposed and the number of heat exchanger fins that can be received in one circular heat exchanger pipe is very small.

[0155] Further, if the lengths D2 and D3 of the apsidal lines of the elliptical heat exchanger pipe shown in FIG. 16B and the oblong heat exchanger pipe shown in FIG. 16C are the same (D2=D3), it is possible to increase the heat transfer area of the elliptical heat exchanger pipe.

[0156] That is, for example, when the width of heat exchanger fins of the elliptical heat exchanger pipe is increased, sixteen heat exchanger fins provide the same heat transfer effect as seventeen heat exchanger fins of the oblong heat exchanger pipe.

[0157] Accordingly, it can be seen that the elliptical heat exchanger pipe 240 of the present invention needs a relatively small number of heat exchanger fins to provide the same heat transfer area rather than increasing the width of the heat exchanger fins in comparison to the oblong heat exchanger pipe.

[0158] The oblong heat exchanger pipe has straight portions spaced in parallel and curved portions connecting the ends of the straight portions, and in this case, it is difficult to manufacture the oblong heat exchanger pipe because coming-off occurs between the heat exchanger fins and the straight portions when the heat exchanger fins are inserted into the oblong heat exchanger pipe and heat transfer does not normally occur if a defect is generated.

[0159] However, the elliptical heat exchanger pipe 240 of the present invention has only a round portion without a straight portion in the entire shape, coming-off described above is prevented in the manufacturing process, thereby considerably increasing the heat transfer rate (i.e., heat exchange rate).

[0160] Further, several heat exchanger fins 242 are provided in the present invention, are disposed on a line extending from a side to the other side of the inner circumferential surface of the heat exchanger tube 241, and are spaced in the direction of the apsidal line of the heat exchanger tube 241.

[0161] FIGS. 17A and 17B are plan views showing other examples of the heat exchanger pipe according to the eighth embodiment of the present invention.

[0162] According to another embodiment of the present invention, as shown in FIGS. 17A and 17B, some of heat exchanger fins 242 are ‘discontinuous type heat exchanger fins 242a’ that are disconnected at the middle portions in the longitudinal direction and the others are ‘continuous type heat exchanger fins 242b’ that are entirely continuous in the longitudinal direction.

[0163] Accordingly, the discontinuous type heat exchanger fins 242a increase the amount of flow of fluid such as combustion gas and fluctuates flowing fluid, thereby increasing the heat exchange rate.

[0164] On the contrary, the continuous type heat exchanger fins 242b prevent deformation of the heat exchanger tube 241, increase productivity, and provide divided exhaust loads that divide and discharge fluid. This is because the continuous type heat exchanger fins 242b provide a strong supporting force (or reinforcing force) and divide the inside of the heat exchanger tube 241.

[0165] In detail, the continuous type heat exchanger fins 242b are integrally formed (or two tub ends are bonded to each other) across the inside of the heat exchanger tube 241, they are used as reinforcing members inserted between the straight portions of the heat exchanger tube 241. Therefore, they prevent deformation of the heat exchanger tube 241.

[0166] Further, when the heat exchanger tube 241 deforms, gaps is generated between the heat exchanger fins 242 and the heat exchanger tube 241 and thermal contact is removed, this problem is solved by one design change rather than improving repeated processes or adding processes, so productivity is improved.

[0167] Further, since the inside of the heat exchanger tube 241 is divided into a plurality of sections by the continuous type heat exchanger fins 242b, one heat exchanger pipe actually provides a plurality of heat exchanger pipes and fluid such as combustion gas is separately discharged.

[0168] In particular, the heat exchanger tube 2241 may include a ‘continuous fin group G1’ in which one or more continuous heat exchanger fins 242b are continuously disposed.

[0169] For example, as shown in FIGS. 17A and 17B, a continuous fin group G1 composed of three continuous type heat exchanger fins 242b are continuously disposed in the heat exchanger tube 241 is provided.

[0170] Obviously, the number of the continuous type heat exchanger fins 242b included in one continuous fin group G1 may be variously adjusted, for example, as two, four, or five.

[0171] However, the larger the number of the continuous type heat exchanger fins 242b included in the continuous fin group G1, the larger the reinforcing force and the more the deformation of the heat exchanger tube 241 is prevented, but the number of the discontinuous type heat exchanger fins 242a decreases, so it is required to appropriately adjust the number of the continuous type heat exchanger fins.

[0172] Further, at least one (i.e., one or more) continuous fin group G1 is provided and may be disposed between the sections composed of discontinuous type heat exchanger fins 242a.

[0173] That is, since the inside of the heat exchanger tube 241 is divided by the continuous fin group G1, a ‘discontinuous fin group G2’ composed of discontinuous type heat exchanger fins 242a and another ‘continuous fin group G1’ may be alternately disposed.

[0174] For example, as shown in FIG. 17A, one continuous fin group G1 is disposed at the entry in the apsidal line of the heat exchanger tube 241, discontinuous type heat exchanger fins 242a are disposed in each of the left and right sections divided by the continuous fin group.

[0175] When two continuous fin groups G1 are provided, a discontinuous type heat exchanger fin 242a is disposed in each of the section between the two spaced continuous fin groups G1 and the sections outside the continuous fin groups G1, so more continuous fin groups G1 can be provided in this way.

[0176] However, the number and lengths of discontinuous type heat exchanger fins 242a sequentially disposed in the section divided by the continuous fin group G1 may be adjusted such that the ends of the discontinuous type heat exchanger fins 242a make an S-shape when they are sequentially connected by a virtual line.

[0177] The S-shape may be formed by one discontinuous fin group G2 or adjacent or spaced several discontinuous fin groups G2.

[0178] Accordingly, fluid fluctuates in an S-shape in the sections in which the separate type heat exchanger fins 242a are disposed, so he heat exchange rate further increases.

[0179] A hot water storage type heat exchanger having an elliptical heat exchanger pipe having the above configuration according to an embodiment of the present invention is described hereafter.

[0180] FIG. 18 is a perspective view showing a hot water storage type heat exchanger having the elliptical heat exchanger pipe according to the eighth embodiment of the present invention.

[0181] As shown in FIG. 18, a hot water storage type heat exchanger 200 having an elliptical heat exchanger pipe according to the present invention includes a heat exchanger body 210 having a water storage space therein.

[0182] The heat exchanger body 210 has an inlet IN at a lower portion through which low-temperature raw water (or pre-heated water) flows inside and an outlet OUT at an upper portion through which hot water or heating water heated through heat exchange is discharged.

[0183] A downward type burner (see 2151 in FIG. 2) is disposed on the heat exchanger body 210 and a predetermined space defined inside the upper portion of the heat exchanger body 210 is used as a combustion chamber 211 into which a flame and combustion gas are spouted.

[0184] A top end plate 220-T, a bottom end plate 220-B, a circular heat exchanger pipe 230, and an elliptical heat exchanger pipe 240 are disposed in the heat exchanger body 210.

[0185] The top end plate 220-T and the end plate 220-B are spaced up and down a predetermined distance apart from each other in the heat exchanger body 210, and the circular exchanger pipe 230 and the elliptical heat exchanger pipe 240 are vertically fitted between the plates.

[0186] The hot water storage type heat exchanger having this configuration according to the present invention enables heat exchange between combustion gas in the heat exchanger body 210 and raw water outside the body, and the raw water heated by heat exchange is supplied as hot water or heating water.

[0187] To this end, the combustion chamber 211 over the top end plate 220-T is exposed to a burner 2151 in FIG. 3 and the bottom end plate 220-B is connected to the exhaust port 2140 in FIG. 3, so high-temperature combustion gas produced in the burner is discharged outside through the heat exchanger pipes 230 and 240.

[0188] FIG. 19 is a plan view showing the hot water storage type heat exchanger having the elliptical heat exchanger pipe according to the eighth embodiment of the present invention.

[0189] As shown in FIGS. 18 and 19, the top end plate 220-T has a disc shape and has a first top stage 220a-T at the center and a second top stage 220b-T around (i.e., outside) the first top stage 220a-T.

[0190] A plurality of circular fitting-holes is formed through the first top stage 220a-T to fit the heat exchanger pipes 230 and elliptical fitting-holes are formed through the second top stage 220b-T to fit the elliptical heat exchanger pipe 240.

[0191] Similarly, the bottom end plate 220-B also has disc shape and has a first bottom stage at the center and a second bottom stage around (i.e., outside) the first bottom stage.

[0192] The bottom end plate 220-B is disposed at the lower end of the heat exchanger body 210 and is spaced in parallel downward from the top end plate 220-T. Accordingly, a water chamber is defined in the space surrounded by the top end plate 220-T, the bottom end plate 220-B, and the heat exchanger body 210 and the heat exchanger pipes 230 and 240 are disposed in the water chamber.

[0193] In the bottom end plate 220-B, similar to the top end plate 220-T, circular fitting-holes in which a plurality of circular heat exchanger pipes 230 is fitted are formed through the first bottom stage and elliptical fitting-holes in which a plurality of elliptical heat exchanger pipes 240 is fitted are formed through the second bottom stage.

[0194] The upper and lower open ends of the circular heat exchanger pipe 230 are connected to the top end plate 220-T and the bottom end plate 220-B, respectively. Since the circular heat exchanger pipes 230 are circular pipes having a circular cross-section, so they are fitted in the circular fitting-holes of the top end plate 220-T and the bottom end plate 220-B.

[0195] In particular, the circular heat exchanger pipes 230 are disposed at the center portions of the top and bottom end plates 220-T and 220-B. That is, the upper ends of the circular heat exchanger pipes 230 pass through the first top stage 220a-T of the top end plate 220-T and the lower ends pass through the first bottom stage of the bottom end plate 220-B.

[0196] Heat exchanger fins are disposed in the circular heat exchanger pipe 230, similar to the elliptical heat exchanger pipe 240 described above. The heat exchanger fins increase a heat transfer amount by increasing the contact surface area with combustion gas.

[0197] The upper and lower open ends of the elliptical heat exchanger pipe 240 are connected to the top end plate 220-T and the bottom end plate 220-B, respectively. Since the elliptical heat exchanger pipes 240 are elliptical pipes having an elliptical cross-section, so they are fitted in the elliptical fitting-holes of the top end plate 220-T and the bottom end plate 220-B.

[0198] In particular, the circular heat exchanger pipes 240 are disposed at the outer portion between the top and bottom end plates 220-T and 220-B. That is, the upper ends of the elliptical heat exchanger pipes 240 pass through the second top stage 220b-T of the top end plate 220-T and the lower ends pass through the second bottom stage of the bottom end plate 220-B.

[0199] Further, as described with reference to FIGS. 15, 16, etc., the heat exchanger fins 242 are inserted in the elliptical heat exchanger pipe 240, thereby increasing the contact surface are with combustion gas and the heat transfer amount.

[0200] Since the long radius of the elliptical heat exchanger pipe 240 is two times larger or more than the radius of the circular heat exchanger pipe 230, the heat transfer area is considerably wide, and short radius of the elliptical heat exchanger pipe 240 is also larger than the radius of the elliptical heat exchanger 240.

[0201] Accordingly, the elliptical heat exchangers 240 are disposed outside (i.e., in the second state of) the end plate having a large circumference and the circular heat exchanger pipes 230 are disposed at the center (i.e., in the first stage) of the end plate having a small circumference.

[0202] Accordingly, the heat transfer area by the entire heat exchanger pipes 220 and 230 to the outer diameter of the entire hot water storage type heat exchanger is considerably increased by the elliptical heat exchangers 240, and a relatively small number of heat exchanger pipes are used to provide the same thermal efficiency, whereby it is possible to reduce the size of the hot water storage type heat exchanger.

[0203] Further, a plurality of elliptical heat exchanger pipes 240 is circumferentially arranged along the second top stage 220b-T and the second bottom stage.

[0204] Accordingly, the ratio of the entire cross-sectional area of the elliptical heat exchanger pipes 240 to the entire area of the second top stage 220b-T (or the second bottom stage) is very large.

[0205] That is, density of the elliptical heat exchanger pipes 240 increases, so the heat transfer area further increases and the heat exchange rate further increases.

[0206] Further, the top end plate 220-T of the present invention may be a multi-stage top end plate 220-T of which the second top stage 220b-T is higher than the first top stage 220a-T.

[0207] Accordingly, when a heat source (e.g., flame and combustion gas) produced by the burner is circumferentially spouted, the distances to the first top stage 220a-T and the second top stage 220b-T are uniform.

[0208] Therefore, concentration of heat transfer at a specific portion in the water chamber in the heat exchanger body 210 is prevented, so low-temperature raw water is uniformly heated.

[0209] The interface 220c-T between the first top stage 220a-T and the second top stage 220b-T of the multi-stage top end plate 220-T is sloped (indicated by a dotted line).

[0210] The sloped interface 220c-T enables smooth flow of fluid such as combustion gas, so combustion gas increases thermal efficiency while they are guided to the circular heat exchanger pipes 230 and the elliptical heat exchanger pipes 240.

[0211] The bottom end plate 220-B of the present invention is also a multi-stage bottom end plate 220-B of which the second bottom stage is higher than the first bottom stage and the multi-stage bottom end plate 220-B has the same steps as the multi-stage top end plate 220-T.

[0212] FIG. 20 is a front view showing the hot water storage type heat exchanger having the elliptical heat exchanger pipe according to the eighth embodiment of the present invention.

[0213] Since the first bottom stage at the center of the bottom end plate 220-B is lower than the second bottom stage disposed around the first bottom stage, only the first bottom stage is shown when seen from the front, as shown in FIG. 20.

[0214] Accordingly, since the circular heat exchanger pipes 230 and the elliptical heat exchanger pipes 240 are the same in length, the distances that the combustion gas flows through the circular heat exchanger pipes 230 and the elliptical heat exchanger pipes 240 are the same, so it uniformly transmits heat to the entire inside of the water tank 1120.

[0215] Specific embodiments of the present invention were described above. However, it would be understood by those skilled in the art that the spirit and scope of the present invention are not limited to the specific embodiments and the present invention may be modified in various ways without departing from the spirit of the present invention. Therefore, the embodiments described above are provided to completely let those skilled in the art of the scope of the present invention, so the embodiments should be understood as only example not limiting the present invention and the present invention is defined only by the range of claims.