ANTI-FREEZING PIPE HAVING BUILT-IN TUBE AND HIGH-EFFICIENCY HEAT EXCHANGER USING THE SAME

Abstract

An anti-freezing pipe having a built-in tube and a high-efficiency heat exchanger using the same, includes a heat transfer pipe made of metal and configured to allow a fluid to move therethrough and a hollow tube located and supported in the heat transfer pipe. The tube has a sealed space defined therein by sealants fitted into both end portions thereof and is provided on an outer diameter surface thereof with a wing formed in a spiral shape, and the heat transfer pipe is 10 provided at an end portion thereof with a stopper to prevent escape of the tube therefrom due to the flow of fluid.

Claims

1. An anti-freezing pipe having a built-in tube, the anti-freezing pipe comprising: a heat transfer pipe configured to allow a fluid to move therethrough; and a hollow tube located and supported in the heat transfer pipe, wherein the tube has a sealed space defined therein by sealants sprayed into both end portions thereof at high pressure and is provided on an outer diameter surface thereof with a wing formed in a spiral shape, and wherein the heat transfer pipe is provided with a stopper to prevent escape of the tube therefrom.

2. The anti-freezing pipe according to claim 1, wherein the wing or the tube is provided with a coating layer integrally formed on an outer surface thereof so as to minimize friction, and wherein the coating layer is implemented as a Teflon coating layer or a chrome plating layer.

3. The anti-freezing pipe according to claim 1, wherein the sealants defining the sealed space in the tube are made of the same material as the tube, wherein the tube and the wing are made of different materials, and wherein the wing is made of metal or thermally conductive plastic and is mounted such that at least a portion thereof is in surface contact with an inner diameter surface of the heat transfer pipe.

4. The anti-freezing pipe according to claim 1, wherein the heat transfer pipe is made of metal, and wherein the stopper is implemented as one selected from among a sleeve provided on an inner diameter surface of the heat transfer pipe, a diameter-contracted portion, a vortex fan unit, and an extension portion.

5. The anti-freezing pipe according to claim 1, wherein the heat transfer pipe is connected to a separate linear connection pipe or a separate U-pipe via a joint portion or is connected to an external structure, and wherein the heat transfer pipe is further provided with a reinforcing member implemented as one selected from among a sleeve mounted on an inner diameter surface or an outer diameter surface of a portion of the heat transfer pipe adjacent to the joint portion and an extension portion overlapping an inner diameter surface of the heat transfer pipe.

6. A high-efficiency heat exchanger comprising: a frame; a flow pipe constituted by a plurality of heat transfer pipes mounted inside the frame; cooling fins connected to the plurality of heat transfer pipes; a U-pipe interconnecting end portions of neighboring ones of the plurality of heat transfer pipes of the flow pipe; a supply header pipe and a discharge header pipe connected to the flow pipe to simultaneously supply or discharge a refrigerant to or from the flow pipe; a tube inserted into each of the plurality of heat transfer pipes; and a connection pipe connected to at least one of the plurality of heat transfer pipes, wherein the tube has a sealed space defined therein by sealants sprayed into both end portions thereof at high pressure and is provided on an outer diameter surface thereof with a wing, and wherein each of the plurality of heat transfer pipes or the connection pipe is provided with a stopper to restrict movement of the tube.

7. The high-efficiency heat exchanger according to claim 6, wherein the stopper is implemented as one selected from among a diameter-contracted portion, a sleeve, an unpowered fan, and an extension portion, and wherein the diameter-contracted portion is provided with a spiral guide groove formed therein.

8. The high-efficiency heat exchanger according to claim 6, wherein each of the plurality of heat transfer pipes comprises a flared enlarged portion formed at an end portion thereof exposed to an outside of the frame, wherein a connection portion formed by performing welding on the enlarged portion is mounted to form an extra space to allow one or more connection portions to be formed when one side of the connection portion is cut, wherein each of the plurality of heat transfer pipes is further provided with a reinforcing member located on an inner diameter surface or an outer diameter surface of the extra space, and wherein the reinforcing member is implemented as one selected from among a sleeve located on the inner diameter surface or the outer diameter surface of the extra space and an extension portion extending from the U-pipe.

9. The high-efficiency heat exchanger according to claim 6, wherein the supply header pipe and the discharge header pipe are connected to each other via a bypass pipe provided therein with a check valve configured to operate at a predetermined pressure or higher.

10. The high-efficiency heat exchanger according to claim 6, wherein the tube and the sealants are made of the same material, wherein the tube and the wing are made of different materials, wherein the wing is made of metal or thermally conductive plastic and is mounted such that at least a portion thereof is in surface contact with an inner diameter surface of each of the plurality of heat transfer pipes, and wherein the wing or the tube is provided with a coating layer integrally formed on an outer surface thereof so as to minimize friction.

11. The high-efficiency heat exchanger according to claim 6, wherein the tube or each of the plurality of heat transfer pipes is formed in a circular or elliptical shape.

12. The high-efficiency heat exchanger according to claim 6, wherein the U-pipe comprises a fractured portion formed thereon so as to allow pressure to be concentrated thereon or is configured such that at least a portion thereof has a smaller thickness than each of the plurality of heat transfer pipes.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and other objects, features, and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0030] FIG. 1 is a perspective view of a conventional freezing-prevention device;

[0031] FIG. 2 is a schematic view of a conventional anti-freezing heat exchanger;

[0032] FIG. 3 is a view showing a mounting state of an anti-freezing heat transfer pipe according to the present invention;

[0033] FIGS. 4 and 5 are, respectively, a perspective view and a cross-sectional view of a tube according to an embodiment of the present invention;

[0034] FIGS. 6 and 7 are views showing a mounting state of a stopper of the anti-freezing heat transfer pipe according to the present invention;

[0035] FIGS. 8 and 9 are views showing a mounting state of a reinforcing member of the heat transfer pipe according to an embodiment of the present invention;

[0036] FIG. 10 is a view showing a mounting state of a reinforcing member of the heat transfer pipe according to another embodiment of the present invention;

[0037] FIGS. 11 and 12 are views showing a mounting state of a heat exchanger according to the present invention;

[0038] FIG. 13 is a view showing an assembled state of heat transfer pipes and cooling fins in the heat exchanger according to the present invention;

[0039] FIG. 14 is a view showing a process of manufacturing the heat transfer pipe according to the present invention;

[0040] FIG. 15 is a view showing an assembled state of the heat transfer pipe and the tube according to the present invention;

[0041] FIG. 16 is a view showing a connected state of a header pipe according to another embodiment of the present invention; and

[0042] FIGS. 17 and 18 are views showing a state in which a U-pipe is connected to the heat transfer pipes according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0043] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0044] As shown in FIGS. 3 to 10, a heat transfer pipe 100 according to the present invention is configured to allow cooling fins 110 to be connected thereto inside a frame 1000 so as to be used in a cooling/heating air conditioner performing cooling or heating using water or refrigerant such as Freon as a heat-exchange medium, a cooling tower, a heat exchanger, a fan coil unit, etc. A hollow tube 200 is mounted in the heat transfer pipe 100.

[0045] In detail, the hollow tube 200 mounted in the heat transfer pipe 100 has a sealed space defined therein.

[0046] In particular, when the heat transfer pipe 100 according to the present invention is applied to a heat exchanger H, a linear connection pipe 180 or a U-pipe 190 is connected to the heat transfer pipe 100. End portions of neighboring heat transfer pipes 100 are connected to each other via the U-pipe 190 so as to form a constant flow of refrigerant. The heat transfer pipe 100 is connected to a supply header pipe 510 or a discharge header pipe 530 via the connection pipe 180.

[0047] In addition, when the heat transfer pipe 100 is provided in plural, a plurality of supply header pipes 510 or a plurality of discharge header pipes 530 is respectively connected to the plurality of heat transfer pipes 100 so as to simultaneously supply or discharge refrigerant to or from the plurality of heat transfer pipes 100.

[0048] Sealants 710 are sprayed at high pressure through a high-pressure nozzle 700 so as to be fitted into both end portions of the tube 200, whereby a sealed space 230 is defined in the tube 200. A wing 270 is integrally formed on the outer circumferential surface of the tube 200.

[0049] In this case, one or more wings 270 protrude in a spiral shape from the outer circumferential surface of the tube 200.

[0050] In addition, a coating layer 290 for minimizing friction may be integrally formed on the outer surface of the wings or the tube.

[0051] The sealants 710 are made of the same material as the tube 200.

[0052] Further, the tube 200 and the wings 270 are made of different materials. In this case, the tube 200 and the wings 270 may be integrally formed with each other through double-injection molding.

[0053] The wings 270 may be made of metal or thermally conductive plastic and may include support plates 271 that are formed in a plate shape for surface contact at portions thereof connected to the tube or portions thereof contacting the inner diameter surface of the heat transfer pipe, as shown in FIGS. 5B and 5C.

[0054] The coating layer is implemented as a Teflon coating layer or a chrome plating layer in order to minimize friction between the outer side of the wings or the tube and a fluid.

[0055] In addition, as shown in FIGS. 6 and 7, the heat transfer pipe 100 includes a stopper 370 formed at an end portion thereof in order to prevent escape of the tube 200 therefrom due to the flow of fluid.

[0056] In this case, the stopper 370 is implemented as any one selected from among a sleeve 371 provided on the inner diameter surface of the heat transfer pipe as shown in FIG. 7A, a diameter-contracted portion 373 shown in FIG. 6, a vortex fan unit 375 shown in FIG. 7B, and an extension portion 380 shown in FIG. 10.

[0057] Further, as shown in FIG. 8, the heat transfer pipe 100 is connected to the separate linear connection pipe 180 or the U-pipe 190 via a weld joint portion 400 or is connected to the header pipe, which is an external structure.

[0058] In addition, as shown in FIGS. 8 and 9, the heat transfer pipe 100 may further include a reinforcing member 360, which is implemented as a sleeve and is provided on the inner diameter surface or outer diameter surface of a portion of the heat transfer pipe 100 that is adjacent to the weld joint portion 400 or on the inner diameter surface or outer diameter surface of an extension portion of the U-pipe.

[0059] When welding is performed on the weld joint portion 400 in order to connect the connection pipe 180 or the U-pipe 190 to the heat transfer pipe 100, thermal fatigue occurs at the heat transfer pipe 100. In order to cope with the thermal fatigue, as shown in FIG. 10, the connection pipe 180 or the U-pipe 190 may include an extension portion 380 extending therefrom so as to contact the inner diameter surface of a portion of the heat transfer pipe 100 at which the thermal fatigue occurs. In this case, the extension portion 380 may serve as the reinforcing member 360.

[0060] The extension portion 380 may be formed by extending an end portion of the connection pipe 180 or the U-pipe 190 or connecting a separate pipe to an end portion of the connection pipe 180 or the U-pipe 190 through welding.

[0061] The heat transfer pipe 100 may be formed as a single piece. Alternatively, as shown in FIG. 3, a plurality of heat transfer pipes 100 may be connected to each other in the longitudinal direction through a connection portion 120.

[0062] Hereinafter, the operation of the present invention configured as described above will be described.

[0063] As shown in FIGS. 3 to 10, according to the present invention, a plurality of heat transfer pipes 100, in each of which the hollow tube 200 is mounted, is mounted in the vertical direction or the horizontal direction inside the frame 1000, and the cooling fins 110 are connected to the outer diameter surfaces of the heat transfer pipes 100, whereby refrigerant flowing through the heat transfer pipes 100 exchanges heat with external air through contact between the heat transfer pipes 100 and the external air.

[0064] In addition, neighboring ones of the heat transfer pipes 100 are connected to each other via the connection pipe 180 and the U-pipe 190 to form a refrigerant path along which the refrigerant supplied thereto flows a predetermined distance for a predetermined period of time while performing heat exchange.

[0065] In addition, when the supply header pipe 510 is mounted to simultaneously supply refrigerant for heat exchange to the heat transfer pipes 100, the discharge header pipe 530 is connected to the other ends of the heat transfer pipes 100 in order to simultaneously discharge the refrigerant that has performed heat exchange from the heat transfer pipes 100.

[0066] In addition, since the hollow tube 200 is mounted in the heat transfer pipe 100, it is possible to solve a problem that the heat transfer pipe 100 is damaged when the refrigerant freezes and increases in volume in winter.

[0067] That is, the contact surface area between the heat transfer pipe 100 and the refrigerant supplied thereto is increased by the tube 200. Therefore, when the refrigerant freezes, the increased volume thereof is absorbed by the sealed space, with a result that the heat transfer pipe 100 is prevented from freezing and bursting, and heat transfer efficiency is improved.

[0068] Further, the sealants 710, which are made of the same material as the tube 200 and are formed in a sol or gel state, are sprayed at high pressure so as to be forcibly fitted into both end portions of the tube 200 through the high-pressure nozzle 700, thereby defining the vacuum sealed space 230 in the tube 200. Therefore, when the refrigerant around the tube 200 presses the surface of the tube 200, the pressure is absorbed by the vacuum sealed space 230.

[0069] In this case, since the sealed space 230 is formed in a vacuum state, the tube 200 is prevented from being damaged by external pressure applied thereto.

[0070] In addition, since the one or more wings 270 protruding from the outer circumferential surface of the tube 200 are disposed in a spiral shape on the periphery of the tube 200, the refrigerant moves easily along the wings 270.

[0071] In addition, since the coating layer 290, which is implemented as a Teflon coating layer or a chrome plating layer, is integrally formed on the outer surface of the wings 270 or the tube 200 in order to minimize friction between the wings 270 or the tube 200 and the refrigerant, it is possible to prevent reduction in flow rate of the refrigerant, thus ensuring smooth flow of the refrigerant.

[0072] Further, when the tube 200 and the wings 270 are made of different materials, for example, when the tube 200 is made of silicon and the wings 270 are made of metal or thermally conductive plastic, the heat of the refrigerant is easily transferred to the heat transfer pipe 100 made of metal.

[0073] In this case, when the wings 270 are made of metal and the support plates 271 are formed at ends of the wings so as to be in surface contact with the inner diameter surface of the heat transfer pipe 100, it is possible to achieve tight coupling between the tube and the heat transfer pipe and more rapid heat transfer.

[0074] Meanwhile, the heat transfer pipe 100 may be directly connected to the header pipe or may be connected to the header pipe via a separate connection pipe 180.

[0075] In this case, since the wings 270 connected to the outer diameter surface of the tube 200 are caught by the stopper 370, which is implemented as the diameter-contracted portion 373 formed such that an end portion of the heat transfer pipe 100 or the connection pipe 180 is contracted in inner diameter (refer to FIG. 6), it is possible to prevent the tube 200 from being exposed to the outside of the heat transfer pipe 100 when the refrigerant flows, thereby preventing reduction in flow rate of the refrigerant.

[0076] In addition, the connection pipe 180 or the heat transfer pipe 100 includes spiral guide grooves 575 formed in an end portion of the diameter-contracted portion 373 in order to allow the refrigerant discharged therefrom to smoothly flow while forming a vortex.

[0077] In this case, as shown in FIG. 6, a pressing punch 577, which has an inner diameter surface shaped corresponding to the diameter-contracted portion 373 of the connection pipe 180 and protrusions 576 formed on the inner diameter surface thereof so as to be shaped corresponding to the guide grooves 575, is provided. When an end portion of the connection pipe 180 is fitted into and pressed against the pressing punch 577, the diameter-contracted portion 373 and the guide grooves 575 are integrally and simultaneously formed.

[0078] In addition, as shown in FIGS. 8 and 9, a flared joint portion 400 is formed at an end of the heat transfer pipe 100 that is exposed to the outside of the frame 1000 so as to be connected to the header pipe. When the U-pipe or the connection pipe is welded to the heat transfer pipe 100, welding is performed along the flared joint portion 400. Accordingly, welding is accurately performed.

[0079] Other than the diameter-contracted portion 373 described above with reference to FIG. 6, the stopper 370 is implemented as any one selected from among the sleeve 371 shown in FIG. 7A, the vortex fan unit 375 shown in FIG. 7B, and the extension portion 380 shown in FIG. 10, which is mounted so as to overlap the inner diameter surface of the heat transfer pipe 100, thereby preventing escape of the tube 200 from the heat transfer pipe 100 due to flow of the refrigerant.

[0080] In this case, the vortex fan unit 375 is configured to form a vortex while being rotated by flow of the refrigerant without using power, thereby allowing the refrigerant to rapidly flow through the heat transfer pipe 100.

[0081] Further, the heat transfer pipe 100 is connected to the separate linear connection pipe 180 or the U-pipe 190 via the weld joint portion 400 or is connected to the header pipe, which is an external structure.

[0082] When external force is applied to the heat transfer pipe 100, the heat transfer pipe 100 may be easily damaged due to thermal fatigue caused by welding performed along the joint portion 400. In order to prevent this problem, as shown in FIGS. 8 and 9, the heat transfer pipe 100 according to the present invention further includes the reinforcing member 360, which is implemented as a sleeve tightly contacting the inner diameter surface or outer diameter surface of a portion thereof that is adjacent to the joint portion 400. The reinforcing member 360 suppresses expansion of the heat transfer pipe 100 when the refrigerant freezes and expands, thereby preventing damage to the heat transfer pipe 100.

[0083] In addition, as shown in FIG. 10, the connection pipe 180 or the U-pipe 190 includes the extension portion 380 extending from an end thereof so as to overlap the inner diameter surface of a portion of the heat transfer pipe 100 at which thermal fatigue occurs when the connection pipe 180 or the U-pipe 190 is connected to the heat transfer pipe 100 by performing welding along the joint portion 400. Such an extension portion 380 serves as the reinforcing member to prevent fracture of the heat transfer pipe 100 due to the thermal fatigue.

[0084] Hereinafter, a heat exchanger according to the present invention to which the above-described heat transfer pipe is applicable will be described with reference to FIGS. 11 to 18.

[0085] According to the present invention, a flow pipe 300 including a plurality of heat transfer pipes 100, each of which is configured to allow cooling fins 110 to be connected to the outer side thereof and has a hollow tube 200 mounted therein, is mounted inside the frame 1000.

[0086] A linear connection pipe 180 or a curved U-pipe 190 is connected to the heat transfer pipe 100 of the flow pipe 300. End portions of neighboring heat transfer pipes 100 of the flow pipe 300 are connected to each other via the U-pipe 190 so as to form a constant flow of refrigerant.

[0087] In this case, the heat transfer pipe 100 may be connected to a header pipe via the connection pipe 180 or may be directly connected to a header pipe without the connection pipe 180.

[0088] In addition, the plurality of heat transfer pipes 100 of the flow pipe 300 are connected to a supply header pipe 510 or a discharge header pipe 530 so that refrigerant is simultaneously supplied to or discharged from the plurality of heat transfer pipes 100.

[0089] Meanwhile, as shown in FIG. 15, the header pipe and an end portion of the heat transfer pipe are connected to each other via the connection pipe 180 having a diameter-contracted end portion. Alternatively, when the heat transfer pipe is directly connected to the header pipe, the heat transfer pipe may be formed to have a diameter-contracted end portion.

[0090] In this case, the inner diameter of the diameter-contracted end portion of the connection pipe 180 is smaller than the outer diameter defined by the wings 270 connected to the outer diameter surface of the tube 200 in order to prevent escape of the wings 270 from the connection pipe 180.

[0091] In addition, the diameter-contracted end portion performs the same function as the stopper 370 shown in FIGS. 6 and 7.

[0092] In addition, when the heat transfer pipe 100 is connected to the header pipe via the connection pipe 180, the connection pipe 180 includes spiral guide grooves 575 formed in the periphery of the diameter-contracted end portion thereof, as shown in FIG. 6.

[0093] In this case, the diameter-contracted end portion and the guide grooves 575 of the connection pipe 180 are integrally formed using a pressing punch 577 that has an inner diameter surface shaped corresponding to the diameter-contracted end portion of the connection pipe 180 and protrusions 576 formed on the inner diameter surface thereof so as to be shaped corresponding to the guide grooves 575.

[0094] Further, the stopper 370 may be selected from among the above-described diameter-contracted end portion, the sleeve 371 provided so as to tightly contact the inner diameter surface of an end portion of the heat transfer pipe 100 or the connection pipe 180 as shown in FIG. 7A, the unpowered fan 375 provided in an end portion of the heat transfer pipe 100 or the connection pipe 180 as shown in FIG. 7B, and the extension portion 380 separately welded to or integrally extending from an end of the connection pipe 180 or the U-pipe 190 as shown in FIG. 10.

[0095] As shown in FIG. 10, the extension portion 380 is formed so as to have a length corresponding to a predetermined portion of the heat transfer pipe 100, i.e., an extra space 680 in the heat transfer pipe 100, when fitted into the heat transfer pipe 100.

[0096] The extension portion 380 may be formed to have a length corresponding to a portion of the heat transfer pipe 100 at which thermal fatigue occurs due to welding performed along the flared joint portion 400. Therefore, the extension portion 380 may serve as the reinforcing member for reinforcing the fatigue portion of the heat transfer pipe 100.

[0097] In addition, as shown in FIG. 14, the heat transfer pipe 100 includes a flared enlarged portion 600 formed at an end portion thereof that is exposed to the outside of the frame 1000. The heat transfer pipe 100 is connected to the header pipe by performing welding along the enlarged portion 600.

[0098] In this case, the enlarged portion 600 is formed using a pipe-enlarging hammer 650 having a conical shape.

[0099] In addition, as shown in FIG. 10, the connection portion 120, which is formed to allow the connection pipe or the U-pipe to be connected thereto through welding along the enlarged portion, is mounted to form an extra space 680 in which one or more connection portions are capable of being formed when one side of the connection portion 120 is cut.

[0100] In addition, as shown in FIG. 16, the supply header pipe and the discharge header pipe are connected to each other via a bypass pipe 800 provided therein with a check valve 810 configured to operate at a predetermined pressure or higher.

[0101] Further, the tube and the heat transfer pipe constituting the flow pipe may be formed in a circular or elliptical shape.

[0102] In addition, as shown in FIG. 13, the cooling fin 110 includes a through-hole 113 formed therein so as to have a larger diameter than the heat transfer pipe 100. After the heat transfer pipe 100 is inserted through the through-hole 113 in the cooling fin 110, a pipe-enlarging rod 315 is fitted into the heat transfer pipe 100 to increase the diameter of the heat transfer pipe 100, thereby allowing the heat transfer pipe 100 to tightly contact the through-hole 113 in the cooling fin 110.

[0103] Meanwhile, according to the present invention, as shown in FIG. 17, the U-pipe 190 may include a fractured portion C formed on one side thereof so that, when pressure occurs, the pressure is concentrated on the fractured portion C and the fractured portion C is broken. Alternatively, as shown in FIG. 18, the U-pipe 190 may be formed to have a smaller thickness than the heat transfer pipe 100 so that the U-pipe 190 is first broken when pressure occurs. Accordingly, maintenance of the product may be easily implemented merely by repairing the U-pipe exposed to the outside.

[0104] In addition, as shown in FIGS. 8 and 9, the present invention may further include a reinforcing member 360 that is implemented as a sleeve located on the outer diameter surface or inner diameter surface of the extra space 680 described above.

[0105] In addition, the extension portion 380 shown in FIG. 10 may serve as the reinforcing member. The reinforcing member may be implemented as the extension portion 380 that is located on the inner diameter surface of the heat transfer pipe 100 and has a length corresponding to a portion of the heat transfer pipe 100 at which thermal fatigue occurs due to welding performed along the flared joint portion 400, and thus may serve to reinforce the fatigue portion of the heat transfer pipe 100.

[0106] Hereinafter, the operation of the heat exchanger according to the present invention will be described.

[0107] As shown in FIGS. 11 to 18, according to the present invention, the plurality of heat transfer pipes 100 constituting the flow pipe 300, in each of which the hollow tube 200 is mounted, is mounted in the vertical direction or the horizontal direction inside the frame 1000, and the cooling fins 110 are connected to the outer diameter surfaces of the heat transfer pipes 100, whereby refrigerant flowing through the heat transfer pipes 100 exchanges heat with external air through contact between the heat transfer pipes 100 and the external air.

[0108] In addition, since the hollow tube 200 is mounted in the heat transfer pipe 100, it is possible to solve a problem that the heat transfer pipe 100 is damaged when the refrigerant freezes and increases in volume in winter.

[0109] That is, the contact surface area between the heat transfer pipe 100 and the refrigerant supplied thereto is increased by the tube 200. Therefore, when the refrigerant freezes, the increased volume thereof is absorbed by the sealed space, with a result that the heat transfer pipe 100 is prevented from freezing and bursting, and heat transfer efficiency is improved.

[0110] In addition, when the header pipe and the heat transfer pipe 100 are connected to each other via the connection pipe 180 having a diameter-contracted end portion, the wings 270 connected to the outer diameter surface of the tube 200 are caught by the diameter-contracted end portion of the connection pipe 180, whereby it is possible to prevent escape of the tube 200 from the heat transfer pipe 100 when the refrigerant flows, thereby preventing reduction in flow rate of the refrigerant.

[0111] Further, the stopper 370 for preventing escape of the tube 200 from the heat transfer pipe 100 is selected from among the above-described diameter-contracted end portion, the sleeve 371 shown in FIG. 7A, the unpowered fan 375 shown in FIG. 7B, and the extension portion 380 shown in FIG. 10. In this way, since one side of the tube 200 is caught by the stopper 370, it is possible to prevent escape of the tube 200 from the heat transfer pipe 100 when the refrigerant flows, thereby preventing reduction in flow rate of the refrigerant.

[0112] In addition, when the header pipe and the heat transfer pipe 100 are connected to each other via the connection pipe 180 having a diameter-contracted end portion, spiral guide grooves 575 are formed in the diameter-contracted end portion of the connection pipe 180, thereby allowing the discharged refrigerant to smoothly flow while forming a vortex.

[0113] In addition, the heat transfer pipe 100 includes a flared enlarged portion 600 formed at an end portion thereof that is exposed to the outside of the frame 1000 so as to be connected to the header pipe. When the U-pipe or the connection pipe is welded to the heat transfer pipe 100, welding is performed along the enlarged portion 600. Accordingly, welding is accurately performed.

[0114] In this case, the enlarged portion 600 is easily formed using a pipe-enlarging hammer 650 having a conical shape.

[0115] In addition, as shown in FIG. 10, the enlarged portion 600 is located in the extra space 680 having a predetermined length, whereby one or more connection portions are capable of being formed when one side of the connection portion 120 is cut.

[0116] In addition, as shown in FIG. 16, the supply header pipe and the discharge header pipe are connected to each other via a bypass pipe 800 provided therein with a check valve 810 configured to operate at a predetermined pressure or higher. Therefore, when the flow pipe 300 is damaged, the refrigerant is directly discharged through the bypass pipe 800, whereby loss of the refrigerant is prevented.

[0117] Further, the tube and the flow pipe may be formed in a circular or elliptical shape.

[0118] In addition, as shown in FIG. 13, the cooling fin 110 includes a through-hole 113 formed therein so as to have a larger diameter than the heat transfer pipe 100. After the heat transfer pipe 100 is inserted through the through-hole 113 in the cooling fin 110, a pipe-enlarging rod 315 is fitted into the heat transfer pipe 100 to increase the diameter of the heat transfer pipe 100, thereby allowing the heat transfer pipe 100 to tightly contact the through-hole 113 in the cooling fin 110. Accordingly, heat transfer efficiency is increased, and connection of the heat transfer pipe 100 is facilitated.

[0119] Meanwhile, according to the present invention, as shown in FIG. 17, the U-pipe 190 includes a fractured portion C formed on one side thereof so that, when pressure occurs, the pressure is concentrated on the fractured portion C and the fractured portion C is broken. Alternatively, as shown in FIG. 18, the U-pipe 190 is formed such that at least a portion thereof has a smaller thickness than the heat transfer pipe 100 so that the U-pipe 190 is first broken when pressure occurs. Accordingly, maintenance of the product may be easily implemented merely by repairing the U-pipe exposed to the outside.

[0120] In addition, as shown in FIGS. 8 and 9, the present invention further includes a reinforcing member 360 that is implemented as a sleeve located on the outer diameter surface or inner diameter surface of the extra space 680 described above. Accordingly, it is possible to disperse pressure generated at the coupling portion during welding along the enlarged portion, thereby preventing the heat transfer pipe from freezing and bursting.

[0121] In addition, as shown in FIG. 10, the extension portion 380 extends from an end portion of the connection pipe 180 or an end portion of the U-pipe 190 so as to have a length corresponding to a portion of the heat transfer pipe 100 at which thermal fatigue occurs when the connection pipe 180 or the U-pipe 190 is connected to the heat transfer pipe 100 by performing welding along the joint portion 400, i.e., the extra space 680 in the heat transfer pipe 100. Since the extension portion 380 is located so as to overlap the inner diameter surface of the heat transfer pipe 100, it is possible to prevent fracture of the heat transfer pipe 100 due to thermal fatigue.

[0122] As is apparent from the above description, the present invention has an effect of absorbing expansion energy generated by freezing of a fluid flowing through a pipe, thereby preventing damage to the pipe due to the expansion energy.

[0123] In addition, the present invention has an effect of easily placing a tube at a desired proper position.

[0124] In addition, the present invention has an effect of ensuring smooth flow of refrigerant and improving the efficiency of a heat exchanger.

[0125] In addition, the present invention has an effect of improving the sealing effect of the tube and preventing collection of foreign substances on the outer side of the tube.

[0126] Although specific embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions, and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.