WO2015002451A1

WO2015002451A1 - Shell tube heat exchanger and method of manufacturing the same

Info

Publication number: WO2015002451A1
Application number: PCT/KR2014/005891
Authority: WO
Inventors: Seok Pyo Hong; Jae Kyoo JANG; Jung Wook Moon; Ju Seok Lee
Original assignee: Lg Electronics Inc.
Priority date: 2013-07-02
Filing date: 2014-07-02
Publication date: 2015-01-08
Also published as: KR20150004177A; CN105518408B; CN105518408A; KR102077565B1

Abstract

The present invention provides a shell tube heat exchanger, comprising: a shell having a coolant inlet, a coolant outlet, a water inlet, and a water outlet; a tube sheet partitioning an inside of the shell into a water path and a coolant path, the tube sheet having a through hole part; and a tube supported by the tube sheet, the tube communicating with the water path so that water passes through the tube, wherein the tube comprises an inner tube through which water passes, the inner tube formed of a copper material; an outer tube surrounding at least a portion of an outer circumferential surface of the inner tube, the outer tube contacting a coolant in the coolant path, wherein the outer tube is formed of an aluminum material; and a packing joined with the inner tube, the packing brought in tight contact with the through hole part, wherein the packing is formed of a copper material. The aluminum-material outer tube may be prevented from being corroded by water with minimized material costs.

Description

SHELL TUBE HEAT EXCHANGER AND METHOD OF MANUFACTURING THE SAME

The present invention relates to a shell tube heat exchanger and a method of manufacturing the same, and more particularly, to a shell tube heat exchanger having an outer tube made of aluminum and an inner tube made of copper and a method of manufacturing the same.

In general, heat exchangers are a device that transfers heat between two fluids and are widely used for cooling and heating and hot water supply.

A heat exchanger may function as a waste heat recovery heat exchanger for recovering waste heat, a cooler for cooling the higher-temperature fluid, a heater for heating the lower-temperature fluid, a compressor for compressing vapor, or an evaporator for evaporating the lower-temperature fluid.

Various types of heat exchangers may be put to use, which include a pin tube heat exchanger having a tube through which a first fluid passes and a pin provided at the tube so that the tube and pin exchange heat between their adjacent second fluid and first fluid, a shell tube air conditioner having a shell through which a first fluid passes and a tube through which a second fluid for heat exchange with the first fluid passes, a dual-pipe heat exchanger having an inner pipe through which a first fluid passes and an outer pipe through which a second fluid heat exchanged with the first fluid passes and which surrounds the inner pipe, and a plate-type heat exchanger having a first fluid and a second fluid passing with an electric heating plate between the first and second fluids.

The present invention aims to provide a shell tube heat exchanger that may minimize coolant leakage while preventing corrosion to the tube by water and a method of manufacturing the same.

To obtain the above objects, according to the present invention, a shell tube heat exchanger comprises a shell having a coolant inlet, a coolant outlet, a water inlet, and a water outlet; a tube sheet partitioning an inside of the shell into a water path and a coolant path, the tube sheet having a through hole part; and a tube supported by the tube sheet, the tube communicating with the water path so that water passes through the tube, wherein the tube comprises an inner tube through which water passes, the inner tube formed of a copper material; an outer tube surrounding at least a portion of an outer circumferential surface of the inner tube, the outer tube contacting a coolant in the coolant path, wherein the outer tube may be formed of an aluminum material; and a packing joined with the inner tube, the packing brought in tight contact with the through hole part, wherein the packing may be formed of a copper material.

The outer tube may be shorter in length than the inner tube.

The packing may be joined with an inner circumferential surface of the inner tube by brazing.

A portion of the packing may be positioned in the water path.

An example of the packing may include an inner water path through which water passes and which communicates with the inner tube.

Another example of the packing may include a smaller diameter part inserted into the inner tube; a larger diameter part contacting the through hole part, the larger diameter part larger in diameter than the smaller diameter part; and a connecting part connecting the smaller diameter part with the larger diameter part.

Still another example of the packing may cover a portion of an outer circumferential surface of the inner tube, which may be not surrounded by the outer tube. The packing may be shaped as a hollow cylinder.

Still another example of the packing may include an outer barrel body surrounding a portion of an outer circumferential surface of the inner tube and a portion of an outer circumferential surface of the outer tube; and a ring body shaped to be bent from the outer barrel body, the ring body covering an end of the inner tube. The packing further may include an inner barrel body shaped to be bent from the ring body, the inner barrel body inserted to an inside of the inner tube.

According to the present invention, a method of manufacturing a shell tube heat exchanger comprises preparing a dual pipe by disposing an aluminum-material outer tube on an outer circumferential surface of a copper-material inner tube; joining a packing with the inner tube; inserting the packing into a through hole part formed in a tube sheet; and pipe-expanding the packing.

According to the present invention, a method of manufacturing a shell tube heat exchanger comprises preparing a dual pipe by disposing an aluminum-material outer tube on a portion of an outer circumferential surface of a copper-material inner tube; joining a packing with the outer circumferential surface of the inner tube; inserting the packing into a through hole part formed in a tube sheet; and pipe-expanding the inner tube.

Preparing the dual pipe may include forming the outer tube so that the outer tube surrounds the overall outer circumferential surface of the inner tube; and peeling off a portion of the aluminum-material outer tube of the dual pipe.

Joining the packing with the inner tube may include placing a mechanism on a portion of the dual pipe, where the aluminum-material outer tube has been peeled off, the mechanism blocking a welding flame from the peeled portion; cooling an inside of the inner tube and a portion adjacent to the packing by jetting nitrogen; and joining the inner tube with the packing by brazing.

The present invention may prevent an aluminum outer tube from being corroded by water while minimizing material costs.

Further, manufacturing process may be simplified, and possibility of coolant and water leakage may be minimized.

Fig. 1 is a cross-sectional view illustrating a shell tube heat exchanger according to a first embodiment of the present invention;

Fig. 2 is a flowchart illustrating a method of manufacturing a shell tube heat exchanger according to a first embodiment of the present invention;

Fig. 3 is a cross-sectional view illustrating a shell tube heat exchanger according to a second embodiment of the present invention;

Fig. 4 is a flowchart illustrating a method of manufacturing a shell tube heat exchanger according to a second embodiment of the present invention; and

Fig. 5 is an expanded cross-sectional view illustrating a main part of a shell tube heat exchanger according to a third embodiment of the present invention.

Hereinafter, embodiments of the present invention are described in detail with reference to the accompanying drawings.

Fig. 1 is a cross-sectional view illustrating a shell tube heat exchanger according to a first embodiment of the present invention.

The shell tube heat exchanger includes a shell 2, a tube 4 disposed in the shell 2, and a tube sheet 6 supporting the tube 4.

The shell 2 may form an outer appearance of the shell tube heat exchanger. The shell 2 includes a coolant inlet 12, a coolant outlet 14, a water inlet 16, and a water outlet 18. The shell 2 may have a space therein. The shell 2 may have therein a coolant path P1 through which a coolant passes and a water path P2 through which water passes. The shell tube heat exchanger may have a tube sheet 6 partitioning the coolant path P1 from the water path P2. The shell 2 may be formed so that the coolant inlet 12 and the coolant outlet 14 go through the coolant path P1. The water path P2 may include a water inlet path P21 through which water introduced to the water inlet 16 flows to the tube 4 and a water outlet path P22 through which water passing through the tube 4 flows to the outside of the water outlet 18. The shell tube heat exchanger may be installed so that the tube 4 communicates the water inlet path P21 with the water outlet path P22.

A coolant may sequentially pass though the coolant inlet 12, the coolant path P1, and the coolant outlet 14, and water may sequentially pass through the water inlet 16, the water inlet path P21, the tube 4, the water outlet path P22, and the water outlet 18. The coolant and water may exchange heat through the tube 4.

The shell tube heat exchanger may be a heat exchanger used in a heater or cooler. The shell tube heat exchanger may function as a condenser in which the coolant introduced into the shell 2 loses heat to water passing through the tube 4 and is thus condensed when the temperature of the coolant is higher than the temperature of the water. The shell tube heat exchanger may function as an evaporator in which the coolant introduced into the shell 2 sucks heat from water passing through the tube 4 when the temperature of the coolant is lower than the temperature of the water and is then evaporated. The shell tube heat exchanger may be used in a freezing cycling apparatus constituted of a compressor, a condenser, an expander, and an evaporator.

The shell 2 may include a shell body 22 having a space therein to form a coolant path P1 and a header 24 coupled with the shell body 22 and having a space forming therein a water path P2. The coolant inlet 12 and the coolant outlet 14 may be formed in the shell body 22, and the water inlet 16 and the water outlet 18 may be formed in the header 24.

The shell body 22 may be shaped as a hollow barrel with both ends opened, and the header 24 may include a first header coupled with an end of the shell body 22 and having the water inlet 16 and a second header coupled with another end of the shell body 22 and having the water outlet 18. In such case, the tube 4 may be arranged long along a length direction of the shell body 22 and its end may communicate with the inside of the first header while another end thereof may communicate with the inside of the second header.

The shell body 22 may have a partitioning plate 26 that may be formed to have a closed end and an opened end. Multiple headers 24 may be coupled with the opened end of the shell body 22. The partitioning plate 26 partitions the water inlet path P21 from the water outlet path P22 in the header 24. In such case, a single header 24 may have a water inlet 16 passing to the water inlet path P21 and a water outlet 18 passing through the water outlet path P22. The tube 4 may include a pair of tube parts arranged long along a length direction of the shell body 22 and a bent part connecting the pair of tube parts and bent like the letter U. The pair of tube parts and the bent part in the tube 4 may be formed as a single body.

The tube 4 may have an end communicating with the water inlet path P1 and another end communicating with the water outlet path P2. The tube 4 may have therein a water passage 5 through which water passes. A plurality of tubes 4 may be provided in a single shell tube heat exchanger. Water may be distributed into the plurality of tubes 4 to exchange heat with the coolant. Hereinafter, the tube 4 is described in greater detail.

The tube sheet 6 may be disposed at the shell 2. The tube sheet 6 may be disposed inside the shell 2. The tube sheet 6 may be positioned between the shell body 22 and the header 24. The tube sheet 6 may have a surface forming a coolant path P1 and another surface forming a water path P2. The tube sheet 6 may have a through hole part 7 tightly contacting the tube 4. The tube 4 may be supported by the tube sheet 7 while in tight contact with the through hole part 7. A plurality of through hole parts 7 may be formed in the tube sheet 6. The through hole part 7 may contact the outer circumferential surface of the tube 4. The through hole part 7 may contact an outer circumferential surface adjacent to an end of one of the tubes 4. The through hole part 7 may be a tube supporting hole supporting the tube 4 or may be a tube through hole through which the tube 4 is arranged to pass.

The tube 4 may have a dual pipe

structure having tubes

42 and 44 respectively formed of different materials. The tube 4 may include an inner tube 42 and an outer tube 44. The inner tube 42 may surround the outer tube 44, and the inner tube 42 and the outer tube 44 may be formed of different materials. The tube 4 may further include a packing 46 that prevents water from the water path P2 to the coolant path P1. The packing 46 may include a water-proof sealing member.

The tube 4 includes an inner tube 42 that has water pass through and is formed of a copper material, an outer tube 44 that surrounds at least part of an outer circumferential surface of the inner tube 42, contacts the coolant in the coolant path P1, and is formed of an aluminum material, and a packing 46 that is coupled with the inner tube 42 and tightly contacts the through hole part 7 and is formed of a copper alloy. As used herein, the copper material may include copper and a copper alloy, and the aluminum material may include aluminum and an aluminum alloy.

In the tube 4, the copper inner tube 42 may be in surface contact with the aluminum-material outer tube 44, and the copper-material inner tube 42 may and the aluminum outer tube 44 may transfer heat through heat conduction. When the coolant introduced into the shell 2 is higher in temperature than the water passing through the inside of the tube 4, the heat from the coolant is delivered to the outer tube 44 and is then transferred from the outer tube 44 to the inner tube 42 so that heat from the inner tube 42 may be transferred to the water.

When the coolant introduced into the shell 2 is lower in temperature than the water passing through the tube 4, the heat from the water is delivered to the inner tube 42 and may be then delivered from the inner tube 42 to the outer tube 44 so that heat from the outer tube 44 may be transferred to the coolant.

The outer tube 44 of the tube 4 may be formed of aluminum to save material costs. The shell tube heat exchanger may adopt a Freon-based coolant as the coolant, and when the outer tube 4 contacting the coolant is formed of an aluminum material having a lower heat conductivity than copper while the inner tube 42 contacting water is formed of a copper material, a decrease in the heat transfer performance may be minimized while material costs are saved. Meanwhile, while the aluminum-material inner tube 42 contacts water, the copper-material inner tube 42 may be less likely to corrode when in contact with water. The tube 4 is preferably formed such that water passes through the copper-material inner tube 42 while the aluminum-material outer tube 44 contacts the coolant.

The inner tube 42 may have a water path 5, and the water path 5 may be formed long in a length direction of the inner tube 42 along the inner tube 42. The overall inner tube 42 is shaped like a U, and the water path 5 may have a U shape.

In a case where the outer tube 44 surrounds only part of a circumferential surface of the inner tube 42, the inner tube 42 may include an outer tube contacting part 42A where the outer tube 44 contacts the circumferential surface and outer tube

non-contacting parts

42B and 42C where the outer tube 44 does not contact the circumferential surface. The inner tube 42 may have the outer tube contacting part 42A positioned between the pair of outer tube

non-contacting parts

42B and 42C in a length direction of the inner tube 42. The inner tube 42 may have the outer tube contacting part 42A positioned between the first outer tube non-contacting part 42B and the second outer tube non-contacting part 42C. The inner tube 42 may have a portion of the circumferential surface, which is positioned adjacent to an end of the inner tube 42 as the first outer tube non-contacting part 42B and another portion of the circumferential surface, which is positioned adjacent to another end of the inner tube 42 as the second outer tube non-contacting part 42C.

The outer tube 44 may be shorter in length than the inner tube 42. In a case where the outer tube 44 surrounds only part of the circumferential surface of the inner tube 42, the outer tube 44 may surround only a portion between the first outer tube non-contacting part 42B and the second outer tube non-contacting part 42C of the inner tube 42 while not surrounding the first outer tube non-contacting part 42B and the second outer tube non-contacting part 42C.

The outer tube 44 is provided to surroujnd the overall circumferential surface of the inner tube 42, and a portion of an end side of the outer tube 44 and a portion of another side thereof may be removed. The outer tube 44 is formed to be shorter than the inner tube 42 upon manufacture, so that the outer tube 44 is disposed on only part of the circumferential surface of the inner tube 42.

The packing 46 may be joined with an inner circumferential surface of the inner tube 42. The packing 46 is formed of the same material as the inner tube 42, so that when the packing 46 forms a brazing joint with the inner tube 42, the packing 46 and the inner tube 42 may be strongly joined together, and the packing 46 may be fixed to the inner tube 42 with high reliability. However, joining the packing 46 with the inner tube 42 is not limited to brazing, and the packing 46 and the inner tube 42 may be joined together by way of other various methods. Part of the packing 46 may be inserted into the inner tube 42, and the inserted part of the packing 46 may be brazing-joined with the inner tube 42. At least a portion of the packing 46 is disposed in the through hole part 7 of the tube sheet 6, preventing water in the water path P2 from contacting the aluminum-material outer tube 42.

The packing 46 is disposed to block a space between the inner tube 42 and the tube sheet 6 to stop water in the water path P2 from flowing to the coolant path P1. A length (L) of the packing 46 may be larger than a thickness (T) of the tube sheet 6. The packing 46 may be shaped as a hollow that may include an inner water path 47 through which water passes. The inner water path 47 may be formed long in a length direction of the packing 46 inside the packing 46. The inner water path 47 may communicate with the inside of the inner tube 42. The packing 46 may have a larger thickness than the outer tube 44.

The packing 46 may include a smaller diameter part 48 inserted into the inner tube 42; a larger diameter part 49 larger in diameter than the smaller diameter part 48 and contacting the through hole part 7; and a connecting part 50 connecting the smaller diameter part 48 with the larger diameter part 49 and whose diameter increases from the smaller diameter part 48 to the larger diameter part 49. The packing 46 may have a portion positioned on the water path P2 of the shell 2. The packing 46 may be arranged through the through hole part 7 of the tube sheet 6. The packing 46 may include a water contacting part 49A positioned in the water path P2 and whose outer circumferential surface contacts water. The packing 46 may include a through hole part contacting part 49B whose outer circumferential surface contacts the through hole part 7. The packing 46 may include a coolant contacting part 49C positioned in the coolant path P1 and whose outer circumferential surface contacts the coolant. The packing 46 may not include the coolant contacting part 49C and may include the water contacting part 48A and the through hole contacting part 49B. The packing 46 may not include the water contacting part 49A and may include the through hole contacting part 49B and the coolant contacting part 49C. The larger diameter part 49 of the packing 46 may include all of the water contacting part 49A, the through hole contacting part 49B, and the coolant contacting part 49C. The packing 46 may function to stop flow of water and coolant and may function as a heat exchanging part that exchanges heat between the water and the coolant.

Two packings 46 may be provided in one inner tube 42. The packings 46 may include a first packing 46A with a portion inserted into an end of the inner tube 42 and a second packing 46B with a portion inserted into another end of the inner tube 42. In the tube 4, the first packing 46A, the inner tube 42, and the second packing 46B may be sequentially arranged in a direction of water flow. Hereinafter, in an embodiment, the description of the common configuration about the first packing 46A and the second packing 46B is replaced by the description of the packing 46, and when intended to distinguish the first packing 46A from the second packing 46B, both the first packing 46A and the second packing 46B are described.

The shell tube heat exchanger, upon manufacture, may have the packing 46 joined with the inner tube 42 positioned at the through hole part 7, thereby pipe-expanding the packing 46. Upon pipe-expanding the packing 46, the diameter of the packing 46 is increased and is thus brought in tight contact with the through hole part 7 of the tube sheet 6, thus minimizing the possibility of leakage of the water and coolant through the tube sheet 6.

The operation of the present invention configured as above is described below.

A coolant may be introduced through the coolant inlet 12 to the inside of the shell 2, in which the coolant may be then brought in contact with the aluminum-material outer tube 44. After heat exchanging with the outer tube 44, the coolant may be discharged through the coolant outlet 14. In the shell tube heat exchanger, when a portion of the copper-material packing 46 is positioned in the coolant path P1, the coolant may be brought in contact with the packing 46 as well as the outer tube 44, and after heat exchanging with the outer tube 44 and the packing 46, the coolant may be discharged through the coolant outlet 14.

The water may be introduced through the water inlet 16 to the water inlet path P21. The water introduced into the water inlet path P21 is blocked by the first packing 46A and is prevented from contacting the outer tube 44. Accordingly, corrosion that may occur when the water is in contact with the outer tube 44 may be prevented. The water may be introduced from the water inlet path P1 to the inside of the first packing 46A, and may flow from the inside of the first packing 46A to the inner tube 42. After flowing to the inner tube 42, the water may exchange heat with the inner tube 42 while passing through the inner tube 42, and may be then introduced to the inside of the second packing 46B. The water introduced into the second packing 46B may pass through the second packing 46B and may be discharged through the water outlet path P22. The water in the water outlet path P22 is blocked by the second packing 46B to be prevented from contacting the outer tube 44. Accordingly, corrosion that may occur when the water is in contact with the outer tube 44 may be prevented. The water flowing from the second packing 46B to the water outlet path P22 may be discharged through the water outlet 18.

Fig. 2 is a flowchart illustrating a method of manufacturing a shell tube heat exchanger according to a first embodiment of the present invention.

The method of manufacturing a shell tube heat exchanger includes preparing a dual pipe (S1), joining a packing (S2), inserting the packing (S3), and pipe-expanding the packing (S4).

Preparing the dual pipe (S1) may include preparing the dual pipe by disposing an aluminum-material outer tube 44 on an outer circumferential surface of a copper-material inner tube 42. Preparing the dual pipe (S1) may include surrounding the aluminum-material outer tube 44 on part of the outer circumferential surface of the copper-material inner tube 42. Preparing the dual pipe (S1) may include peeling off a portion of the aluminum-material outer tube 44 of the dual pipe. A portion of the outer circumferential surface of the inner tube 42 in the dual pipe may be externally exposed. The tube 4 is provided so that the outer tube 44 wraps around the overall outer circumferential surface of the inner tube 42, and a portion of an end side and a portion of another end side of the outer tube 44 are removed, thus peeling off the dual pipe. That is, preparing the dual pipe (S1) may include forming the outer tube 44 to surround an overall outer circumferential surface of the inner tube 42 and peeling off a portion of the aluminum-material outer tube 44. The outer tube 44 may be formed to be shorter in length than the inner tube 42 from when the outer tube 44 is manufactured, and the outer tube 44 may be formed so that a portion of the outer circumferential surface of the inner tube 42 is externally exposed upon its formation.

Joining the packing (S2) may include combining the packing 46 with the inner tube 42 prepared in preparing the dual pipe (S1). A portion of the packing 46 may be inserted to the inside of the inner tube 42. The smaller diameter part 48 of the packing 46 may be inserted into the inner tube 42, and the packing 46 and the inner tube 42 may be joined to each other by brazing or by an adhesive. The packing 46, the inner tube 42, and the packing 46 may be integrally formed. When the packing 46 and the inner tube 42 are joined to each other by brazing, joining the packing (S2) may include positioning a mechanism on a portion of the tube 4, where the aluminum-material outer tube has been peeled off, to prevent a welding flame from the portion. Joining the packing (S2) may include jetting nitrogen to the inside of the copper-material inner tube 42 and a region adjacent to the packing 46 to cool the same.

Joining the packing (S2) may include brazing-joining the inner tube 42 and packing 46 of the same material to each other. When the inner tube 42 and the packing 46 are joined to each other, the copper-material inner tube 42 is not melted down by nitrogen jetting that has been previously performed, and its shape may be maintained. Joining the packing (S2) may further include removing the mechanism positioned on the portion where the aluminum-material outer tube has been peeled off after brazing-joining the inner tube 42 with the packing 46. When the packing 46 is joined with the inner tube 42, the larger diameter part 49 may be positioned outside the inner tube 42. Packings 46 may be provided at both ends, respectively, of the inner tube 42. In the tube 4, the larger diameter part of the first packing 46A, the inner tube 42, and the larger diameter part of the second packing 46B may be arranged in the order thereof in a length direction of the tube 4.

Inserting the packing (S3) may include inserting the dual pipe-coupled packing 46 into the through hole part 7 formed in the tube sheet 6. The packing 46 may be inserted into the tube sheet 6 so that the larger diameter part 49 is positioned at the through hole part 7 of the tube sheet 6, and the packing 46 may be disposed through the through hole part 7 of the tube sheet 6 with the packing 46 coupled with the inner tube 42.

Pipe-expanding the packing (S4) may include pipe-expanding the packing 46 inserted into the through hole part 7 of the tube sheet 6 in inserting the packing (S3). Pipe-expanding the packing (S4) may include inserting a pipe-expanding ball into the packing 46 and rotating it. When the pipe-expanding step is performed with the pipe-expanding ball, the packing 46 is pipe-expanded so that its outer circumferential surface is brought in tight contact with the through hole part 7 of the tube sheet 6, and the packing 46 of the tube 4 may be fixed to the tube sheet 6.

Fig. 3 is a cross-sectional view illustrating a shell tube heat exchanger according to a second embodiment of the present invention.

According to this embodiment, in the shell tube heat exchanger, a portion of the outer circumferential surface of the inner tube 42 is not surrounded by the outer tube 44, and the packing 46' may be wrapped by a portion of the outer circumferential surface of the inner tube 42, which is not surrounded by the outer tube 44. In this embodiment, the shell tube heat exchanger has the same or similar configuration and operation to the shell tube heat exchanger described in connection with the first embodiment except for the packing 46', and the same denotations may be used to refer to the same elements and detailed description thereof may be skipped.

The packing 46' may prevent water in the water path P2 from contacting the aluminum-material outer tube 44. The packing 46' may be positioned between the water path P2 and the outer tube 44. The packing 46' may be positioned to block a space between the inner tube 42 and the tube sheet 6 so that the water in the water path P2 is prevented from flowing to the coolant path P1 and the coolant in the coolant path P1 from flowing to the water path P2. The packing 46' may be shaped as a hollow cylinder.

A portion of the inner tube 42, which is not surrounded by the outer tube 44, may be inserted into the packing 46'. The packing 46' may include a water contacting part 49A that is positioned in the water path P2 and whose outer circumferential surface contacts water. The packing 46' may include a through hole contacting part 49B whose outer circumferential surface contacts the through hole part 7. The packing 46' may include a coolant contacting part 49C that is positioned in the coolant path P1 and whose outer circumferential surface contacts the coolant. The packing 46' may not include the coolant contacting part 49C and may include the through hole contacting part 49B and the water contacting part 48A. The packing 46' may include the through hole contacting part 49B and the coolant contacting part 49C without the water contacting part 49A. The packing 46' may include all of the water contacting part 49A, the through hole contacting part 49B, and the coolant contacting part 49C. The packing 46' may form a dual pipe with the inner tube 42. In the tube 4, the inner tube 42 and the outer tube 44 may constitute a dual pipe of different materials as in an embodiment of the present invention, or the inner tube 42 and the packing 46' may form a dual pipe of the same material.

The packing 46' may be joined with the inner tube 42 by brazing or an adhesive. The packing 46' may have a hollow in which an inner water path 47 through which water passes may be formed. The packing 46' may include a first packing 46A' into which a portion of the inner tube 42, which is not surrounded by the outer tube 44, is inserted and that passes through a first through hole part of the tube sheet 6 and a second packing 46B' into which another portion of the inner tube 42, which is not surrounded by the outer tube 44, is inserted and that passes through a second through hole part of the tube sheet 6. The first packing 46A', the outer tube 44, and the second packing 46B' in the tube 4 may be sequentially arranged in a length direction of the tube 4.

Upon manufacture of the shell tube heat exchanger, the packing 46' joined with the inner tube 42 may be positioned in the through hole part 7 of the tube sheet 6, and the inner tube 42 may be pipe-expanded. Upon pipe-expanding the inner tube 42, the inner tube 42 and the packing 46' may be expanded in their diameter, and at this time, the packing 46' may be brought in tight contact with each of the inner tube 42 and the tube sheet 6 at a position between the outer circumferential surface of the inner tube 42 and the through hole part 7 of the tube sheet 6. The inner tube 42, after the packing 46' has been provided, may be pipe-expanded by a pipe-expanding ball, and upon pipe-expanding the inner tube 42, a portion of the inner tube 42 may be pipe-expanded and may be brought in tight contact with the packing 46'. Upon pipe-expanding the inner tube 42, the packing 46 is pushed by the inner tube 42 that is subjected to pipe-expanding, so that its diameter may be increased. The packing 46' with increased diameter may be brought in tight contact with the tube sheet 6. Upon pipe-expanding the inner tube 42, the possibility of coolant and water leakage through the tube sheet 6 may be minimized.

Meanwhile, the present invention is not limited to the above embodiment. An end of the outer tube 44 and an end of the packing 46' may be both positioned in the through hole part 7 of the tube sheet 6, and the outer tube 44 and the packing 46' each may be brought in tight contact with the through hole part 7 of the tube sheet 6. In such case, the outer tube 44 may include a coolant contacting part contacting the coolant and a through hole contacting part contacting the through hole part 7 of the tube sheet 6. The packing 46' may include the water contacting part 49A contacting water and the through hole contacting part 49B contacting the through hole part 7 of the tube sheet 6 without the coolant contacting part contacting the coolant.

Fig. 4 is a flowchart illustrating a method of manufacturing a shell tube heat exchanger according to a second embodiment of the present invention.

The method of manufacturing the shell tube heat exchanger includes preparing a dual pipe (S1), joining the packing (S2'), inserting the packing (S3), and pipe-expanding the inner tube (S4').

Preparing the dual pipe (S1) may include preparing a dual pipe by disposing an aluminum-material outer tube 44 on a portion of an outer circumferential surface of a copper-material inner tube 42. Preparing the dual pipe (S1) may include surrounding the outer tube 44 on the overall outer circumferential surface of the inner tube 42 and peeling off a portion of the aluminum-material outer tube 44 of the dual pipe. The outer tube 44 may be formed to be shorter in length than the inner tube 42 from when the outer tube 44 is manufactured. The outer tube 44, upon forming the same, may be formed so that a portion of the outer circumferential surface of the inner tube 42 is externally exposed.

Joining the packing (S2') may include joining the packing 46' on the outer circumferential surface of the inner tube 42. A portion of the inner tube 42, with an outer circumferential surface not surrounded by the outer tube 44 may be inserted into the packing 46'. The packing 46' and the inner tube 42 may be joined with each other by brazing or an adhesive. The packing 46', the inner tube 42, and the outer tube 44 may be integrally formed. When the packing 46' and the inner tube 42 are joined with each other by brazing, joining the packing (S2') may be the same or similar to joining the packing (S2) in the method of manufacturing a heat exchanger according to the embodiment of the present invention except that a portion of the inner tube 42 is inserted into the packing 46', and detailed description thereof is skipped.

Inserting the packing (S3) may include inserting the packing 46' into the through hole part 7 of the tube sheet 6. Inserting the packing (S3) may be the same or similar to inserting the packing (S3) in the method of manufacturing a heat exchanger according to the above embodiment of the present invention except that the packing 46' positioned at the outer circumferential surface of the inner tube 42, together with the inner tube 42, may be inserted into the through hole part 7 of the tube sheet 6 and that a portion of the inner tube 42 and the packing 46' together are inserted into the through hole part 7 of the tube sheet 6, and detailed description thereof is skipped.

Pipe-expanding the inner tube (S4') may include pipe-expanding the inner tube 42. Pipe-expanding the inner tube (S4') may include pipe-expanding the packing 46' inserted into the through hole part 7 of the tube sheet 6 by inserting the packing (S3) and a portion of the inner tube 42, which is surrounded by the packing 46'. Pipe-expanding the inner tube (S4') may include inserting a pipe-expanding ball into the inner tube 42 and rotating it. In the pipe-expanding step by the pipe-expanding ball, the inner tube 42 may be pipe-expanded by the pipe-expanding ball, and upon pipe-expanding the inner tube 42, the packing 46' is pushed by the inner tube 42 that is being pipe-expanded so that its diameter may be increased. The outer circumferential surface of the packing 46' with increased diameter may be brought in tight contact with the tube sheet 6. A portion of the inner tube 42 in the tube 4 and the packing 46' may be fixed to the tube sheet 6.

Meanwhile, the present invention is not limited to the above embodiment. After preparing the dual pipe (S1), a peeled portion of the outer tube 44 of the dual pipe may be inserted into the through hole part 7 of the tube sheet 6. Or, the packing 46' may be inserted into a portion between the peeled portion of the outer tube 44 of the dual pipe and the through hole part 7 of the tube sheet 6, and the inner tube 42 and the packing 46' may be then joined with each other. After joining the packing, pipe-expanding the inner tube 42 (S4') may be performed as well.

Fig. 5 is a cross-sectional view illustrating a main part of a shell tube heat exchanger according to a third embodiment of the present invention.

The shell tube heat exchanger according to this embodiment may include an outer barrel body 51 in which a packing 46" surrounds a portion of an outer circumferential surface of the inner tube 42 or a portion of an outer circumferential surface of an outer tube 44; and a ring body 52 shaped to be bent from the outer barrel body 51 and covering an end of the inner tube 42. The packing 46" may further include an inner barrel body 53 shaped to be bent from the ring body 52 and inserted to the inside of the inner tube 42.

The outer barrel body 51 may be brought in tight contact with the through hole part 7 of the tube sheet 6 and may be fixed to the through hole part 7 of the tube sheet 6. The outer barrel body 51 may be shaped as a hollow cylinder. In the tube 4, the outer tube 44 surrounds the overall outer circumferential surface of the inner tube 42 while the outer barrel body 51 surrounds a portion of the outer circumferential surface of the outer tube 44. In the tube 4, as in the second embodiment of the present invention, the outer tube 44 surrounds only a portion of the outer circumferential surface of the inner tube 42 while the outer barrel body 51 surrounds a portion of the outer circumferential surface of the inner tube 42, which is not surrounded by the outer tube 44, and in such case, the outer barrel body 51 may have the same configuration in function and position as the packing 46' according to the second embodiment of the present invention.

The ring body 52, when the outer barrel body 51 surrounds a portion of the outer circumferential surface of the outer tube 44, may cover both an end of the outer tube 44 and an end of the inner tube 42, and when the outer barrel body 51 surrounds a portion of the outer circumferential surface of the inner tube 42, the ring body 52 may cover an end of the inner tube 42.

The inner barrel body 53 may be shaped as a hollow cylinder and may be inserted into the inner tube 42. The inner barrel body 53 may have a diameter smaller than the diameter of the outer barrel body 51. A space 54 may be formed between the ring body 52 and the outer barrel body 51. When the outer barrel body 51 surrounds a portion of the outer circumferential surface of the outer tube 44, a portion of the inner tube 42 and a portion of the outer tube 44 may be both inserted in the space 54. When the outer barrel body 51 surrounds a portion of the outer circumferential surface of the inner tube 42, a portion of the inner tube 42 may be inserted in the space without a portion of the outer tube 44 inserted therein. The outer circumferential surface of the inner barrel body 53, when installing the packing 46", may be brought in tight contact with the inner circumferential surface of the inner tube 42. The inner barrel body 53 may have a water path 55 in which water passes and which communicates with the inner tube 42.

The other configurations and operations of the shell tube heat exchanger according to this embodiment than the packing 46" are the same or similar to those in the second embodiment of the present invention, and the same denotations are used to refer to the same elements, while detailed description thereof is skipped. The method of manufacturing a shell tube heat exchanger according to this embodiment is the same or similar in configuration and operation to the method according to the second embodiment of the present invention except that the packing 46" is installed and the inner barrel body 53 of the inner tube 42 is then pipe-expanded, and detailed description thereof is skipped.

Claims

A shell tube heat exchanger, comprising:

a shell having a coolant inlet, a coolant outlet, a water inlet, and a water outlet;

a tube sheet partitioning an inside of the shell into a water path and a coolant path, the tube sheet having a through hole part; and

a tube supported by the tube sheet, the tube communicating with the water path so that water passes through the tube, wherein the tube comprises,

an inner tube through which water passes, the inner tube formed of a copper material;

an outer tube surrounding at least a portion of an outer circumferential surface of the inner tube, the outer tube contacting a coolant in the coolant path, wherein the outer tube is formed of an aluminum material; and

a packing joined with the inner tube, the packing brought in tight contact with the through hole part, wherein the packing is formed of a copper material.
The shell tube heat exchanger of claim 1, wherein the outer tube is shorter in length than the inner tube.
The shell tube heat exchanger of claim 1, wherein the packing is joined with an inner circumferential surface of the inner tube by brazing.
The shell tube heat exchanger of claim 1, wherein a portion of the packing is positioned in the water path.
The shell tube heat exchanger of claim 1, wherein the packing includes an inner water path through which water passes and which communicates with the inner tube.
The shell tube heat exchanger of claim 1, wherein the packing includes:

a smaller diameter part inserted into the inner tube;

a larger diameter part contacting the through hole part, the larger diameter part larger in diameter than the smaller diameter part; and

a connecting part connecting the smaller diameter part with the larger diameter part.
The shell tube heat exchanger of claim 1, wherein the packing covers a portion of an outer circumferential surface of the inner tube, which is not surrounded by the outer tube.
The shell tube heat exchanger of claim 7, wherein the packing is shaped as a hollow cylinder.
The shell tube heat exchanger of claim 1, wherein the packing includes:

an outer barrel body surrounding a portion of an outer circumferential surface of the inner tube and a portion of an outer circumferential surface of the outer tube; and

a ring body shaped to be bent from the outer barrel body, the ring body covering an end of the inner tube.
The shell tube heat exchanger of claim 9, wherein the packing further includes an inner barrel body shaped to be bent from the ring body, the inner barrel body inserted to an inside of the inner tube.
A method of manufacturing a shell tube heat exchanger, the method comprising:

preparing a dual pipe by disposing an aluminum-material outer tube on an outer circumferential surface of a copper-material inner tube;

joining a packing with the inner tube;

inserting the packing into a through hole part formed in a tube sheet; and

pipe-expanding the packing.
A method of manufacturing a shell tube heat exchanger, the method comprising:

preparing a dual pipe by disposing an aluminum-material outer tube on a portion of an outer circumferential surface of a copper-material inner tube;

joining a packing with the outer circumferential surface of the inner tube;

inserting the packing into a through hole part formed in a tube sheet; and

pipe-expanding the inner tube.
The method of claim 11 or 12, wherein preparing the dual pipe includes:

forming the outer tube so that the outer tube surrounds the overall outer circumferential surface of the inner tube; and

peeling off a portion of the aluminum-material outer tube of the dual pipe.
The method of claim 13, wherein joining the packing with the inner tube includes:

placing a mechanism on a portion of the dual pipe, where the aluminum-material outer tube has been peeled off, the mechanism blocking a welding flame from the peeled portion;

cooling an inside of the inner tube and a portion adjacent to the packing by jetting nitrogen; and

joining the inner tube with the packing by brazing.