JP2015010757A - Triple-tube type heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a triple-tube type heat exchanger securing high heat exchange efficiency while constituting an inner tube and a leakage detecting tube to be multi-lobate tubes with crest portions and trough portions repeatedly arranged in the circumferential direction.SOLUTION: A triple-tube type heat exchanger (1) includes an inner tube (2) constituted by a multi-lobate tube of which tube wall has a corrugated shape with crest portions (2b) and trough portions (2a) repeatedly arranged in the circumferential direction, a leakage detecting tube (3) constituted by a multi-lobate tube in the almost same shape as the inner tube (2) and externally fitted to the inner tube (2) to be arranged near an outer peripheral surface of the inner tube (2), and an outer tube (4) storing the inner tube (2) and the leakage detecting tube (3) in an inside thereof, and is constituted to enable heat exchange between fluid flowing in an inside (5) of the inner tube (2) and fluid flowing in a gap (6) between the leakage detecting tube (3) and the outer tube (4), and a cross-sectional shape in a section perpendicular to an axial center of the multi-lobate tubes of the inner tube (2) and the leakage detecting tube (3) has straight portions (2c and 3c) connecting crest portions (2b and 3b) and trough portions (2a and 3a), and the inner tube (2) and the leakage detecting tube (3) are in close contact with each other at least in the straight portions (2c and 3c).

Description

  The present invention relates to a triple-pipe heat exchanger, and more particularly, a triple-pipe heat in which a multi-leaf tube having a double structure including an inner pipe and a leak detection pipe fitted to the inner pipe is accommodated inside the outer pipe. Regarding the exchanger.

  In hot water storage and hot water storage devices that store hot water heated by gas combustion heat source devices, heat pump heat source devices, fuel cells, etc., heating devices that use hot water, and other various industrial fields, there is a gap between hot and cold fluids. Various heat exchangers for heat exchange are used.

  In particular, the double-pipe heat exchanger has been widely adopted because it has excellent heat exchange performance and is advantageous in terms of manufacturing cost. Recently, the pipe wall as an inner pipe repeats crests and troughs in the circumferential direction. A double tube heat exchanger in which a multi-leaf tube having a corrugated shape is used and the multi-leaf tube is housed inside an outer tube is also employed.

  For example, in the double-pipe heat exchanger disclosed in Patent Document 1, an inner tube made up of a corrugated multi-leaf tube that alternately repeats crests and valleys in the circumferential direction is housed inside the outer tube, The tops of the six peaks are brought into close contact with the inner peripheral surface of the outer tube, and the six valleys are formed in a state of being separated from each other.

  Here, for example, in a double-pipe heat exchanger used in a hot water storage and hot water supply apparatus, for example, when a coolant is caused to flow in the inner pipe and hot water is caused to flow in a gap between the inner pipe and the outer pipe, the inner pipe is cracked. If generated, the refrigerant may leak and be mixed into the hot water.

  Therefore, in Patent Document 2, when the fluid flowing inside the tube member leaks to the outside of the tube member, the leakage is detected and the leaked fluid is prevented from being mixed into the fluid outside the tube member. In addition, a double structure leak detection tube is disclosed in which a leak detection outer tube having a large number of leak detection grooves formed on the inner peripheral surface thereof is tightly fitted to the tube member.

  The radiator of Patent Document 3 is installed in a hot water storage tank of a heat pump water heater, and this radiator disposes three circular cross-section heat transfer tubes apart from each other, and the outer surfaces of these heat transfer tubes are arranged. The structure is covered with a cladding tube. The cladding tube prevents the refrigerant inside the heat transfer tube from entering the fluid outside the cladding tube when the refrigerant leaks from the heat transfer tube.

JP 2008-232449 A Japanese Patent No. 3933083 JP 2006-250417 A

In a double-pipe heat exchanger as described in Patent Document 1, a leak detection tube as a cladding tube is provided outside the inner tube made of a multi-leaf tube, and Patent Document 2 covers the entire inner surface of the leak detection tube. It is conceivable to form a large number of leak detection grooves as described.
However, in the double pipe heat exchanger, since there are air layers in the multiple leak detection grooves, and the heat transfer area between the inner pipe and the leak detection pipe is reduced, the heat exchange performance is improved. This is not only difficult, but the processing cost for forming a large number of leakage detection grooves is also expensive.

  Even if the radiator of Patent Document 3 can be applied to a double-pipe heat exchanger, this radiator has a structure in which three circular cross-section heat transfer tubes are covered with a cladding tube, so the number of members of the heat transfer tube Many manufacturing costs are high.

  An object of the present invention is to provide a triple pipe heat exchanger that can ensure high heat exchange performance while constituting an inner tube and a leak detection tube in a multi-leaf tube that repeats a crest and a trough in the circumferential direction. is there.

  The triple pipe heat exchanger according to claim 1 includes an inner tube made of a multi-leaf tube having a corrugated shape in which a tube wall repeats a crest and a trough in the circumferential direction, and a multi-leaf tube having substantially the same shape as the inner tube. A leakage detection tube that is externally fitted to the inner tube and disposed in the vicinity of the outer peripheral surface of the inner tube, and an outer tube in which the inner tube and the leakage detection tube are housed. A triple-pipe heat exchanger configured to be able to exchange heat between a fluid flowing inside and a fluid flowing in a gap between the leak detection tube and the outer tube, the inner tube and the leak detection The cross-sectional shape of the axial cross section of the multi-leaf tube of the tube has a straight portion connecting the peak portion and the valley portion, and the inner tube and the leak detection tube are in close contact with each other at least in the straight portion. It is characterized by.

  The triple pipe heat exchanger according to claim 2 is the invention according to claim 1, wherein most of the crests of the inner tube are in close contact with the crests of the leak detection tube and the crests of the leak detection tube Mostly, it is characterized by being in close contact with the outer tube.

According to the first aspect of the present invention, the inner tube is composed of a multi-leaf tube, and is composed of a multi-leaf tube having substantially the same shape as the inner tube, and is fitted on the inner tube and arranged in the vicinity of the outer peripheral surface of the inner tube. A triple tube heat exchanger comprising a leak detection tube and an outer tube in which the inner tube and the leak detection tube are housed, and an axial center of the inner tube and the multi-leaf tube of the leak detection tube The cross-sectional shape of the orthogonal cross section has a straight portion connecting the peak portion and the trough portion, and at least the straight tube has the inner tube and the leak detection tube in close contact with each other. Therefore, the heat exchange performance for exchanging heat between the fluid flowing in the inner tube and the fluid flowing in the gap between the leak detection tube and the outer tube is excellent.
In addition, since the inner tube and the leak detection tube are in close contact with each other in the linear portion, the inner tube and the leak detection tube are more integrated, which is advantageous in increasing the rigidity against vibrations propagated from the fluid.

  According to the invention of claim 2, most of the crests of the inner tube are in close contact with the crests of the leak detection tube, and most of the crests of the leak detection tube are in close contact with the outer tube. Therefore, the overall rigidity of the triple pipe heat exchanger can be increased.

It is sectional drawing of the inner tube | pipe and leak detection tube of the triple tube | pipe type heat exchanger which concerns on the Example of this invention. Partial perspective view of a double multi-leaf tube consisting of an inner tube and a leak detection tube It is sectional drawing of a triple pipe type heat exchanger. It is a fragmentary perspective view of a triple pipe type heat exchanger.

  Hereinafter, modes for carrying out the present invention will be described based on examples.

A triple-pipe heat exchanger 1 according to the present invention will be described with reference to FIGS.
The triple tube heat exchanger 1 includes an inner tube 2, a leak detection tube 3, and an outer tube 4. The inner pipe 2, the leak detection pipe 3, and the outer pipe 4 are manufactured using a material pipe having a predetermined length made of, for example, a copper pipe for water tap having a circular cross section made of phosphorous deoxidized copper or an equivalent product thereof. The thickness of the tube wall of the material pipe is, for example, 0.6 to 1.0 mm, and the outer diameter of the triple pipe heat exchanger is, for example, 16 to 20 mm. However, these numerical values are illustrative and are not limited thereto.

  The inner tube 2 is configured as a multi-leaf tube having a corrugated shape in which the tube wall repeats a crest 2b and a trough 2a in the circumferential direction. The leak detection tube 3 is a multi-leaf tube having substantially the same shape as the inner tube 2, and is fitted on the inner tube 2 and arranged in the vicinity of the outer peripheral surface of the inner tube 2. An inner tube 2 and a leak detection tube 3 are housed inside the outer tube 4.

  Inside the inner pipe 2, an inner fluid passage 5 is formed which is composed of a fluid passage 5 a surrounded by four valleys 2 a and four fluid passages 5 b inside the crest 2 b, and a leak detection pipe 3 and an outer pipe 4 are formed. The outer fluid passage 6 including four fluid passages 6a having a substantially triangular cross section is formed between the fluid and the fluid (for example, a heat pump refrigerant) flowing inside the inner tube 2 (inner fluid passage 5), and the leak detection tube 3. Heat exchange with a fluid (for example, hot water for hot water supply) flowing through a gap 6a (outer fluid passage 6) between the outer pipe 4 and the outer pipe 4 is possible.

When the inner tube 2 and the leak detection tube 3 are manufactured, a double-walled multi-leaf tube 7 (hereinafter referred to as a double tube) is formed by processing a double tube in which the material tube of the inner tube 2 is inserted into the material tube of the leak detection tube 3. 2). In a state where the double multi-leaf tube 7 is inserted into the material tube of the outer tube 4, at least the outer tube 4 is reduced in diameter to manufacture the triple tube heat exchanger 1. Note that both the double multi-leaf tube 7 and the outer tube 4 may be reduced in diameter.
In the manufacturing stage of the triple tube heat exchanger 1, a straight heat exchanger having a length of 6 m, for example, is manufactured, and then cut into a desired length, for example, spirally wound a plurality of times. The coil-shaped triple tube heat exchanger is used for use.

  As shown in FIG. 2, the double multi-leaf tube 7 is formed in a spirally twisted shape with a predetermined lead angle. The predetermined lead angle is an angle that makes one rotation for every 300 to 500 mm in the axial direction, for example. Since the above twist is added, it becomes easy to wind the triple tube heat exchanger 1 when it is configured as a heat exchanger having a coil structure, and the triple tube heat exchanger A stirring action can be obtained with respect to the fluid flowing through the inside of the tank. However, the above twisting is not essential and may be omitted.

  The inner pipe 2 has four valleys 2a and four peaks 2b, the valley 2a has an arc shape, and the peaks 2b have a shape with curved portions at both ends of the arc. The four valley portions 2a are arranged at 90 ° intervals in the circumferential direction around the fluid passage 5a having a substantially square cross section at the center, and the vicinity of the tip of each valley portion 2a is in contact with the valley portion 2a adjacent in the circumferential direction. ing. Therefore, the rigidity of the inner pipe 2 is increased at the center side portion of the triple-pipe heat exchanger 1, and the inner pipe 2 is less likely to be damaged by vibrations propagated from the fluid.

  The leak detection tube 3 has four valleys 3a and four peaks 3b, the valleys 3a have an arc shape, and the peaks 3b have a shape with curved portions at both ends of the arc. . Each trough 3a is located in the vicinity of the outer surface of the trough 2a of the corresponding inner pipe 2, and a crescent-shaped fluid is provided between each trough 2a of the inner pipe 2 and the corresponding trough 3a of the leak detection pipe 3. A gap 8 through which can be circulated is formed. Therefore, for example, when a refrigerant leaks from the inner tube 2 into the gap 8, the occurrence of fluid leakage from the inner tube 2 can be reliably detected by detecting it. In addition, since the curvature radius of the trough part 2a is small and it is easy to generate | occur | produce and damage a big stress, it is easy to detect the leak from the inner tube 2 by forming the clearance gap 8 between the trough part 2a and the trough part 3a. Become.

The cross-sectional shape of the cross-section orthogonal to the axis of the multi-leaf tube of the inner tube 2 has a straight portion 2c that connects the peak 2b and the valley 2a, and the cross-section of the cross-section orthogonal to the axis of the multi-leaf tube of the leak detection tube 3 The shape includes a straight portion 3c that connects the peak portion 3b and the trough portion 3a, and the straight portion 2c of the inner tube 2 and the straight portion 3c of the leak detection tube 3 opposed to the straight portion 3c are in close contact with each other. Yes. Note that the straight portions 2c and 3c are strip-like tube walls twisted in a spiral shape, and the fluid flowing through the inner fluid passage 5 since the strip-like tube walls 2c and 3c are in close contact. And the heat exchange performance between the fluid flowing in the outer fluid passage 6 is enhanced. In addition, since the integrity of the inner tube 2 and the leak detection tube 3 is increased, it is advantageous in securing rigidity.
The peak portion 2b and the pair of linear portions 2c connected to the peak portion 2b are formed in a fan shape with an opening angle of about 45 °, and the same applies to the leak detection tube 3.

Most of the crest 2b of the inner tube 2 is in close contact with the inner surface of the crest 3b of the leak detection tube 3, and most of the crest 3b of the leak detection tube 3 is in surface contact with the inner surface of the outer tube 4. It is closely attached to the shape. Therefore, the overall rigidity of the triple pipe heat exchanger 1 can be increased, and the heat exchange performance between the fluid flowing in the inner fluid passage 5 and the fluid flowing in the outer fluid passage 6 is also improved.
Further, a small crescent-shaped gap 9 is formed between the inner tube 2 and the leak detection tube 3 on both sides of each peak portion 2 b of the inner tube 3. This is because both sides of the ridge 2b have a small radius of curvature, and thus there is a high possibility that a large stress will occur.

Next, since the operation and effect of the triple pipe heat exchanger 1 are as described in detail in the above description, they will be briefly described below.
In the triple tube heat exchanger 1, the inner tube 2 and the leak detection tube 3 constitute a double multi-leaf tube 7, and the double multi-leaf tube 7 is housed inside the outer tube 4. The heat transfer area for heat exchange between the fluid in the inner fluid passage 5 and the fluid in the outer fluid passage 6 can be increased. As a result, the triple pipe heat exchanger 1 with high heat exchange performance is obtained.

  Since the leak detection tube 3 is externally fitted to the inner tube 2 and disposed in the vicinity of the outer peripheral surface of the inner tube 2, most of the outer peripheral surface of the inner tube 2 is in surface contact with most of the inner peripheral surface of the leak detection tube 3. It became a structure. Therefore, the heat exchange performance could be improved. In addition, even if fluid leaks from the inner pipe 2, it is confined in the leak detection pipe 3 and does not leak to the outer fluid passage 6, thereby improving the quality and reliability of the triple pipe heat exchanger 1. I was able to. Further, since the inner tube 2 is composed of one material tube, the number of members is reduced, and the manufacturing cost can be reduced.

  Since the gap 8 is formed between the valley portions 2a and 3a, when the fluid leaks from the inner pipe 2, the leakage can be detected through the gap 8. Since the straight portions 2c and 3c were brought into close contact with each other, heat exchange performance could be improved. Since the vicinity of the tip of the valley portion 2a of the inner tube 2 is in close contact with the adjacent valley portion 2a, the rigidity of the inner tube 2 in the center side portion of the triple tube heat exchanger 1 and the double multi-leaf The rigidity of the tube 7 can be increased.

  Most of the crest 2b of the inner tube 2 is in close contact with the inner surface of the crest 3b of the leak detection tube 3, and most of the crest 3b of the leak detection tube 3 is in intimate contact with the inner surface of the outer tube 4. Therefore, the overall rigidity of the triple pipe heat exchanger 1 can be increased, and the heat exchange performance can also be improved. Since the double multi-leaf tube 7 is spirally twisted, when the triple tube heat exchanger 1 is wound into a coil shape to make a heat exchanger, it becomes easy to wind the inner fluid passage 5 and A stirring action for the fluid flowing in the outer fluid passage 6 is obtained.

Next, an example in which the above embodiment is partially changed will be described.
1) The number of valleys 2a and 3a and the number of peaks 2b and 3b in the double multi-leaf tube 7 including the inner tube 2 and the leakage detection tube 3 are not limited to four, and may be three or five or more.

  2) The metal material of the material tube of the inner tube 2, the leak detection tube 3 and the outer tube 4 is not limited to phosphorous deoxidized copper, but may be other various copper materials, and may be a metal other than copper (for example, aluminum or The alloy, brass, magnesium alloy, titanium, etc.) may be used. The inner tube 2, the leak detection tube 3, and the outer tube 4 are not necessarily manufactured from a material tube of the same kind of metal material, but may be manufactured from a material tube of a different kind of metal material. Moreover, the thickness of the tube wall of the inner tube 2 and the thickness of the tube wall of the leak detection tube 3 may be the same or different.

3) The shape of the outer contour of the cross section of the triple-pipe heat exchanger 1 can be configured to have a shape other than a circle (for example, an ellipse or an oval).
4) The outer diameter of the triple pipe heat exchanger 1 is not limited to the one described in the above embodiment, and can be set to various outer diameters.
5) In addition, those skilled in the art can implement the present invention in a form in which various modifications are added without departing from the spirit of the present invention.

  A triple-pipe heat exchanger that is used for heat exchange between two kinds of fluids and that can be used in various industrial fields is disclosed.

DESCRIPTION OF SYMBOLS 1 Triple pipe type heat exchanger 2 Inner pipe 2a Valley part 2b Mountain part 2c Straight line part 3 Leakage detection pipe 3a Valley part 3b Mountain part 3c Straight line part 4 Outer pipe 5 Inner fluid path 6 Outer fluid path 7 Double multileaf pipe 8 Clearance 9 Clearance

Claims (2)

An inner tube consisting of a multi-leaf tube having a corrugated shape in which the crest and trough are repeated in the circumferential direction in the circumferential direction, and a multi-leaf tube having substantially the same shape as this inner tube, and is fitted to the inner tube to be fitted to the inner tube. A leakage detection tube disposed in the vicinity of the outer peripheral surface; an outer tube in which the inner tube and the leakage detection tube are housed; a fluid flowing in the inner tube; the leakage detection tube; A triple pipe heat exchanger configured to be able to exchange heat with a fluid flowing in a gap between the pipes;
The cross-sectional shape of the cross-section of the inner tube and the multi-leaf tube of the leak detection tube that is orthogonal to the axial center has a straight portion connecting a peak and a valley, and at least the straight tube has the inner tube and the leak detection tube. And a triple tube heat exchanger characterized by the fact that they are in close contact with each other.   The most part of the peak part of the inner pipe is in close contact with the peak part of the leak detection pipe, and the most part of the peak part of the leak detection pipe is in close contact with the outer pipe. The triple tube heat exchanger as described.