KR102018855B1 - Internal heat exchanger - Google Patents

Abstract

The present invention forms an inner passage and includes an inner tube having an inlet and an outlet; An outer tube that radially surrounds at least a portion of the inner tube and is spaced radially outward from the inner tube to form an annular space; And a thermally conductive spiral element wound around the inner tube and disposed in the space, the spiral element together with the inner tube and the outer tube forming a spiral flow path through the space, wherein the spiral flow path is the outer tube. In fluid communication with the inlet and outlet of the outer tube, the outer tube is thermally separated from the helical element. The invention further provides joint rings connecting the outer tube to the inner tube.

Description

Internal Heat Exchanger {INTERNAL HEAT EXCHANGER}

This application claims the benefit of priority of US provisional application 61 / 427,822, filed December 29, 2010, which is hereby incorporated by reference.

The present invention relates to an internal heat exchanger, more particularly a double pipe internal heat exchanger for application in motor vehicles, wherein the pipes are separated by springs or helical elements that provide a helical outer fluid passage.

Heat exchangers are usually used in air conditioners, for example in the form of carbon dioxide air conditioners, which can be used in motor vehicles, for example. The internal heat exchanger serves to transfer heat from the refrigerant on the high pressure side to the refrigerant on the low pressure side, whereby the so-called coefficient of performance, i.e. the ratio of the refrigeration capacity of the air conditioner and the input power, is significantly increased.

Improvements in efficiency and performance can be achieved through the use of coaxial heat exchangers in which liquid refrigerant flows around the outside of the suction tube. Heat is transferred from the liquid to the suction line which increases the subcooling of the liquid line. However, known internal heat exchangers are not always capable of maximum heat transfer in the short compact length of the suction line.

The present invention forms an inner passage and includes an inner tube having an inlet and an outlet; An outer tube that radially surrounds at least a portion of the inner tube and is spaced radially outward from the inner tube to form an annular space; And a thermally conductive spiral element wound around the inner tube and disposed in the space, the spiral element together with the inner tube and the outer tube forming a spiral flow path through the space, wherein the spiral flow path is the outer tube. In fluid communication with the inlet and outlet of the outer tube, the outer tube is thermally separated from the helical element.

The outer tube may be spaced radially outward from the helical element and form a bypass flow path to thermally separate from the helical element.

The bypass flow path can accommodate less than about 5% of the total flow through the bypass flow path and the spiral flow path.

The bypass flow path can accommodate less than approximately 1% of the total flow through the bypass flow path and the spiral flow path.

The outer tube can be thermally separated from the spiral element by an insulating layer interposed between the spiral element and the outer tube.

The helical element can be welded with the inner tube.

The helical element can be held firmly against the outer diameter of the inner tube by the inherent elasticity of the helical element, which may for example be in the form of a spring. More specifically, the helical element can have an inner diameter that is less than the outer diameter of the inner tube when it is not assembled to the inner tube (not elastically supported), so that the helical element can elastically expand to slide over the inner tube and Then the elasticity of the helical element is released and the helical element is contracted around the inner tube and retained in the inner tube by a radially inward biasing force.

The helical element may be in contact with the inner tube over substantially the entire length of the helical element.

The axial ends of the outer tube can be welded with the inner tube.

The outer tube can be connected with the inner tube via joint rings at respective axial ends of the outer tube.

The helical element can be freely moved axially with respect to at least one of the inner and outer tubes, preferably the outer tube, so that the heat exchanger can be bent along its axial length without damaging the heat exchanger.

The aforementioned general features of the present invention can be applied individually or collectively to heat exchangers according to another aspect of the present invention, the heat exchanger comprising: an inner tube forming an inner passage and having an inlet and an outlet; An outer tube that radially surrounds at least a portion of the inner tube and is spaced radially outward from the inner tube to form an annular space; And a thermally conductive spiral element wound around the inner tube and disposed in the space, wherein the spiral element forms a spiral flow path surrounding the inner tube and penetrates the annular space with the inner tube and the outer tube, wherein the spiral flow path is the outer tube. In fluid communication with the inlet and outlet of the helical element in continuous contact with the inner tube along most of the length of the helical element, the helical element integrally attached to the inner tube by welding or soldering, or the helical element It is elastically deflected to the inner tube to remain tight.

The inner tube has a smooth outer diameter surface.

The outer diameter surface has a uniform diameter along its length surrounded by the helical element.

The aforementioned general features of the present invention can be applied individually or collectively to heat exchangers according to another aspect of the present invention, the heat exchanger comprising: an inner tube forming an inner passage and having an inlet and an outlet; An outer tube radially surrounding at least a portion of the inner tube in an overlapping region spaced radially outwardly of the inner tube and forming an annular space therein; A thermally conductive spiral element wound around the inner tube and disposed in the space of the overlap region; And a first joint ring configured to secure the outer tube to the inner tube at the first axial end of the outer tube and having a first radial hole, wherein the helical element, together with the inner tube and the outer tube, of the overlapping region. A helical flow path is formed through the space, and the helical flow path is in fluid communication with the first radial hole.

The heat exchanger may further comprise a second joint ring configured to secure the outer tube to the inner tube at the second axial end of the outer tube, the second joint ring including a second radial hole and the helical flow path being the second In fluid communication with the radial hole.

The first joint ring may comprise a central hole, a first mating hole and a second mating hole having a diameter substantially the same as the outer diameter of the inner tube, the first mating hole being the middle of the diameter of the center hole and the second mating hole. Having a diameter, the diameter of the second mating hole is substantially the same as the outer diameter of the outer tube, the central hole receiving the inner tube, and the second mating hole receiving the outer tube therein.

The first radial hole can be disposed in the first relative hole.

The outer tube can be thermally separated from the helical element.

The foregoing and other features of the present invention are described in more detail below with reference to the accompanying drawings.
1 is a schematic diagram of an air conditioning system of an automobile,
2 is a perspective view of a heat exchanger according to the present invention comprising an outer tube and joint rings shown by a ghost line,
3 is a partial cross-sectional view of a heat exchanger,
FIG. 3A is an enlarged view of FIG. 3, but shows that an inner helical element is spaced apart from the outer tube and a heat exchanger is relatively thermally isolated from the outer tube,
4 is a side view of the heat exchanger,
5 is a perspective view of another heat exchanger according to the present invention including an outer tube shown by a ghost line,
6 is a partial cross-sectional view of the heat exchanger of FIG. 5,
7 is a side view of the heat exchanger of FIG. 5.

The heat exchanger according to the present invention can be used in many applications, but for convenience of explanation and understanding, it will be described herein with reference to the air conditioning system used in motor vehicles. Also, the use of the terms pipe and tube, etc. (pipe member) is used interchangeably and does not necessarily mean a limited definition unless the context requires otherwise. Also, the term "spiral" tends to include "helical" and is used interchangeably with helical.

1 is a schematic diagram of an exemplary air conditioning system 100 that may be used in accordance with aspects of the present invention. The vehicle may have an engine room 1 holding the engine 10 therein and a cabin 2 separated from the engine room 1 by a dash panel 3. The air conditioning system 100 may include a refrigerant cycle device 100A including an expansion valve 131 and an evaporator 141 and an internal unit 100B. The components of the refrigerant cycle apparatus 100A (usually excluding the expansion valve 131 and the evaporator 141) may be arranged in a predetermined mounting space of the engine room 1. The interior unit 100B may be arranged in an instrument panel located in the cabin 2.

The inner unit 100B may include an air conditioner case 101 that houses a blower 102, an evaporator 141, a heater 103, and components of the inner unit 100B. Blower 102 optionally receives outside air or inside air to send air to evaporator 141 and heater 103. The evaporator 141 is a cooling heat exchanger for evaporating the refrigerant used in the refrigerant cycle to absorb the latent heat of vaporization of the refrigerant so that the air is cooled. The heater 103 may use hot water (eg, engine coolant) for cooling the engine 10 as a heat source for heating air to be blown into the cabin 2.

The air mixing door 104 may be disposed near the heater 103 in the air conditioner case 101. The air mixing door 104 may be operated to adjust the mixing ratio between the cold air cooled by the evaporator 141 and the hot air heated by the heater 103 so that air having a desired temperature is delivered to the cabin 2. Can be.

The refrigerant cycle device 100A may include a compressor 110, a condenser 120, an expansion valve 131, and an evaporator 141. The tubes 150 may connect these parts of the refrigerant cycle apparatus 100A to form a closed circuit. At least one double wall tube 160 of the present invention may be disposed in the tubes 150. Condenser 120 (eg, refrigerant radiator, gas cooler, etc.) serves as a high pressure heat exchanger for cooling the high pressure and high temperature refrigerant. The evaporator 141 may be arranged to serve as a low pressure heat exchanger and cool the air passing through it. Expansion valve 131 is a pressure reducer such as a throttle or ejector.

In the example shown, the compressor 110 is driven through the engine 10 to compress the low pressure refrigerant to provide the high temperature and high pressure refrigerant to the refrigerant cycle apparatus 100A. The pulley 111 is attached to the drive shaft of the compressor 110. The drive belt 12 extends between the pulley 111 and the crankshaft pulley 11 to drive the compressor 110 through the engine 10. The pulley 111 is connected to the drive shaft of the compressor 110 through an electromagnetic clutch (not shown). The electromagnet clutch connects the pulley 111 with the drive shaft of the compressor 110 or separates the pulley 111 from the drive shaft of the compressor 110. The condenser 120 is connected to the discharge side of the compressor 110. The condenser 120 is a heat exchanger that cools the refrigerant through external air to condense the refrigerant vapor into the liquid refrigerant.

The expansion valve 131 reduces the pressure of the refrigerant discharged from the condenser 120 and expands the refrigerant. The expansion valve 131 may be a pressure reducing valve capable of reducing the pressure of the liquid refrigerant in an isentropic state. The expansion valve 131 included in the inner unit 100B is usually disposed near the evaporator 141. The expansion valve 131 may be a temperature controlled expansion valve having a variable orifice, and may control the flow of the refrigerant flowing from the evaporator 141 and flowing to the compressor 110 so that the refrigerant is heated to a predetermined superheat. As mentioned above, the evaporator 141 is a cooling heat exchanger for cooling the air to be blown into the cabin. The discharge side of the evaporator 141 is connected to the suction side of the compressor (110).

The double wall tube 160 may be formed by combining a portion of the high pressure tube 151 of the tubes 150 and a portion of the low pressure tube 152. The high pressure tube 151 extends between the condenser 120 and the expansion valve 131 to carry the high pressure refrigerant before depressurization. The low pressure tube 152 extends between the evaporator 141 and the compressor 110 to carry the low temperature low pressure refrigerant after being decompressed and cooled.

For example, when the above air conditioning system is activated, the following process may occur: When the passenger in the cabin wants to operate the air conditioning system 100 for cooling operation, the compressor ( The electromagnet clutch may be engaged to drive 110. Then, the compressor 110 sucks the refrigerant discharged from the evaporator 141, compresses the refrigerant, and discharges the high temperature and high pressure refrigerant to the condenser 120. The condenser 120 cools the high temperature and high pressure refrigerant to a substantially completely liquid liquid state. The liquid refrigerant of the condenser 120 passes through a liquid tube 164 connected with the double wall tube 160 and passes through an annular space formed between the inner tube 162 and the outer tube 161 of the double wall tube 160. Flows into the expansion valve 131. Expansion valve 131 reduces the pressure of the liquid refrigerant and allows the liquid refrigerant to expand. Evaporator 141 evaporates the liquid refrigerant into a substantially saturated gas refrigerant. The refrigerant evaporated by the evaporator 141 absorbs heat from the air flowing through the evaporator 141 to cool the air to be blown to the cabin. The saturated gas refrigerant evaporated by the evaporator 141, ie, the low temperature low pressure refrigerant, flows to the compressor 110 through the suction tube, the inner tube 162 and the suction tube.

Heat is transferred from the high temperature and high pressure refrigerant (eg, up to approximately 600 Psi) flowing through the double wall tube 160 to the low temperature low pressure refrigerant flowing through the double wall tube 160. Thus, in the double wall tube 160, the high temperature high pressure refrigerant is cooled and the low temperature low pressure refrigerant is heated. The liquid refrigerant discharged from the condenser 120 is typically supercooled and its temperature drops while the liquid refrigerant flows through the double wall tube 160. The saturated gaseous refrigerant discharged from the evaporator 141 is typically superheated with the gaseous refrigerant having a superheat degree.

2 and 3, a double wall tube heat exchanger 160 is shown in accordance with the present invention. In FIG. 2 the outer tube 161 is shown with ghost lines so that the inner parts of the heat exchanger can also be seen.

Spirally wound springs or other helical elements 170 may be wound around the inner tube 162 and fluid flow (eg, along the inner side of the outer tube 161 and the outer side of the inner tube 162). , A spiral passage for the liquid refrigerant). The helical element 170 may be tightly wound or otherwise in thermal contact with the inner tube 162 directly or indirectly to improve thermal conductivity with the inner tube. For example, the outer side of the inner tube 162 can be smooth to maximize the area of contact with the spiral element 170 surrounding the inner tube. Optionally, helical element 170 may be welded to inner tube 162 to improve thermal conductivity with the inner tube. The inner, outer and helical elements may each have a uniform diameter over at least the same portions in the axial direction.

As mentioned, the helical element can be held firmly against the outer diameter of the inner tube by the inherent elasticity of the helical element, which may for example be in the form of a spring. More specifically, the helical element may have an inner diameter that is less than the outer diameter of the inner tube when it is not assembled to the inner tube (not elastically supported), so that the spiral element may elastically expand to slide over the inner tube. And then the elasticity of the helical element is released and the helical element is contracted around the inner tube and held in the inner tube by a biasing force radially inward.

Spiral element 170 may be composed of a material having high thermal conductivity, for example a metal material, such as aluminum. Inner tube 162 and outer tube 161 may also be composed of a thermally conductive material, for example metal materials, such as aluminum.

The outer tube 161 has an inlet 180 and an outlet 181. Inlet 180 is connected to, for example, condenser 120 of air conditioning system 100. The liquid is thus forced to sweep the outer surface of the helical element 170 and the inner tube 162 along the helical path. This flow path can have a reduced cross-sectional area compared to a double wall heat exchanger without a spiral element of a corresponding size. This reduced cross-sectional flow path increases the fluid flow rate, thus increasing the effect of convective cooling. The helical flow path also increases the length of the flow path as compared to double wall heat exchangers without helical elements, while using the same amount of physical space. The increased length of the flow path can also increase the heat transfer efficiency that occurs at heat exchanger 160.

Spiral element 170 may be thermally separated from the inner side of outer tube 161 as shown in FIG. 3A. This thermal separation can be achieved, for example, by the annular gap 175 between the outer tube 161 and the helical element 170. Therefore, this gap can form a bypass flow path. Preferably, the bypass flow path may occupy less than approximately 5% of the total flow between the inner tube 162 and the outer tube 161. More preferably, the bypass flow passage may occupy less than approximately 1% of the total flow between the inner tube 162 and the outer tube 161. This thermal separation can exhibit surprising performance, for example, to prevent conduction from the outer tube 161 to the helical element 70 and the inner tube 162.

Alternatively, thermal separation can be achieved, for example, via one or more layers of insulating material 185. The insulating material 185 may extend substantially along the entire inner surface of the outer tube 161, extend only along the helical elements, or intermittently along the length of the inner surface of the outer tube to serve as a spacer.

The outer tube 161 may be indirectly attached to the inner tube 162 by, for example, one or more end fitting rings 190 as shown in FIGS. End joint ring 190 may be, for example, a cylindrical piece that includes a central hole 191 sized to secure around an outer surface of inner tube 162. End joint ring 190 may further include a first mating hole (or mating sink) 192 that is larger than inner tube 162 but smaller than the outer surface of outer tube 161. Finally, the joint ring 190 may include a second mating hole 193 sized to secure the outer surface of the outer tube 161. The joint ring 190 may have radial holes or passages 195 and 196 that serve as inlets and / or outlets of the joint ring and as spiral passages. The radial hole may be located in the first relative hole 192.

Alternatively, the outer tube 161 may be attached directly to the inner tube, for example by swaging and / or welding, as shown in FIGS. 5-7. The outer tube 161 may include first and second radial holes 197, 198 that serve as inlets and / or outlets of the helical flow path.

Although the flow through the outer helical path is shown and described as being in the same direction as the flow through the inner pipe, the flow may be reversed, resulting in opposite flow of refrigerant in the gas and liquid state. Such reverse flow may be desirable in some cases and may result in other heat transfer efficiencies.

Tubes made of a material other than aluminum, such as steel or copper, may be used instead of tubes 161 and 162 made of aluminum.

As can be seen, the helical element can be freely moved axially relative to at least one of the inner and outer tubes, in particular the outer tube, so that the heat exchanger can be bent along its axial length without damaging the heat exchanger.

Although the double wall tube 160 of the present invention has been described for use in the refrigerant cycle apparatus 100A of the automotive air conditioning system 100, the present invention is not limited to this in practical applications. The double wall tube 160 can be used suitably for an indoor air conditioner. When the double wall tube 160 is used in an indoor air conditioner, the ambient temperature around the outer tube 161 is lower than the temperature of the air in the engine room 1. Accordingly, when heat transfer conditions between the high pressure refrigerant and the low pressure refrigerant are allowed, the low pressure refrigerant may be set to pass through the space between the inner tube 162 and the outer tube 161, and the high pressure refrigerant may be set in the inner tube 162. It can be set to pass through the inner passage.

The refrigerant flowing through the double wall tube 160 is not limited to the refrigerant employed in the refrigerant cycle apparatus 100A, and a refrigerant having physical properties different from those of the refrigerant employed in the refrigerant cycle apparatus 100A may be used. have. For example, refrigerants flowing in different directions, refrigerants having different temperatures, or refrigerants having different pressures may be used in combination. In addition, fluids other than the refrigerant of the refrigerant cycle apparatus 100A may be used in the double wall tube 160.

While the present invention has been shown and described with respect to particular embodiments or embodiments, it will be apparent to one skilled in the art that equivalents and modifications may be made by reading and understanding this specification and the accompanying drawings. The term (including what is referred to as "means") used to describe the aforementioned elements, in particular with respect to the various functions performed by the aforementioned elements (parts, assemblies, devices, components, etc.). Are not intended to be structurally equivalent to the disclosed structure for carrying out the functions of the exemplary embodiments or embodiments of the invention herein, unless otherwise indicated, any element (ie, functional that performs a particular function of the described element) Equivalent to In addition, while specific features of the invention have been described with reference to only one or more of the various illustrated embodiments, such features may be combined with one or more other features of other embodiments as such features may be desirable and beneficial for a given or particular application. Can be.

Claims (24)

An inner tube forming an inner passage and having an inlet and an outlet;
An outer tube that radially surrounds at least a portion of the inner tube and is spaced radially outward from the inner tube to form an annular space; And
A thermally conductive spiral element wound around the inner tube and disposed in the space;
The helical element is a spring that is held tightly against the outer diameter of the inner tube by the inherent resiliency of the helical element,
The helical element forms a helical flow path through the space with the inner tube and the outer tube, the helical flow path in fluid communication with the inlet and the outlet of the outer tube,
The outer tube is thermally separated from the spiral element,
heat transmitter.
The method of claim 1,
And the outer tube is thermally separated from the helical element by forming an annular gap spaced radially outward from the helical element and defining a bypass flow path.
The method of claim 2,
And the bypass flow passage receives less than 5% of the total flow rate through the bypass flow passage and the spiral flow passage.
The method of claim 2 or 3,
And the bypass flow passage receives less than 1% of a total flow rate through the bypass flow passage and the spiral flow passage.
An inner tube forming an inner passage and having an inlet and an outlet;
An outer tube that radially surrounds at least a portion of the inner tube and is spaced radially outward from the inner tube to form an annular space; And
A thermally conductive spiral element wound around the inner tube and disposed in the space;
The helical element is a spring held firmly against the outer diameter of the inner tube by the inherent elasticity of the helical element,
The helical element forms a helical flow passage surrounding the inner tube and penetrates the annular space with the inner and outer tubes, the spiral flow passage in fluid communication with the inlet and the outlet of the outer tube,
The helical element is in continuous contact with the inner tube along the main length of the helical element and the helical element is integrally attached to the inner tube by welding or brazing, or the spiral element is held firmly in the inner tube. It is characterized in that it is elastically supported by the inner tube,
heat transmitter.
The method according to claim 1 or 5,
And the inner tube has a smooth outer diameter surface.
The method of claim 6,
And the outer diameter surface has a uniform diameter along its length surrounded by the helical element.
The method according to claim 1 or 5,
And the outer tube is thermally separated from the spiral element by an insulating layer.
The method of claim 8,
The insulating layer extends substantially along the entire inner surface of the outer tube, along the helical element only, or intermittently disposed along the length of the inner surface of the outer tube to serve as a spacer. group.
The method according to claim 1 or 5,
And said spiral element is not attached to at least one of said inner tube or outer tube.
The method according to claim 1 or 5,
Wherein the windings of the helical element are spaced axially apart.
The method according to claim 1 or 5,
And the spiral element is welded to the inner tube.
The method according to claim 1 or 5,
And said helical element contacts said inner tube over substantially the entire length of said helical element.
The method according to claim 1 or 5,
And an axial end of the outer tube is welded to the inner tube.
The method according to claim 1 or 5,
The outer tube is connected to the inner tube by a joint ring at respective axial ends of the outer tube.
The method according to claim 1 or 5,
A first joint ring configured to secure the outer tube to the inner tube at a first axial end of the outer tube, the first joint ring including a first radial hole, the spiral flow path being the A heat exchanger in fluid communication with the first radial hole.
The method of claim 16,
A second joint ring further configured to secure the outer tube to the inner tube at a second axial end of the outer tube, the second joint ring including a second radial hole, the spiral flow path being the A heat exchanger in fluid communication with the second radial hole.
The method of claim 17,
The first joint ring includes a central hole, a first mating hole and a second mating hole of a diameter substantially the same as the outer diameter of the inner tube, wherein the first mating hole is the diameter of the center hole and the diameter of the second mating hole. Wherein the diameter of the second mating hole is substantially the same as the outer diameter of the outer tube, the central hole receiving the inner tube and the second mating hole receiving the outer tube therein. Heat exchanger characterized in that.
The method of claim 18,
And the first radial hole is disposed in the first mating hole.
An inner tube forming an inner passage and having an inlet and an outlet;
An outer tube radially surrounding at least a portion of the inner tube in an overlapping region spaced radially outwardly of the inner tube and forming a gap therein;
A thermally conductive spiral element wound around the inner tube and disposed in a gap of the overlapping region, the spiral element being a spring held firmly against the outer diameter of the inner tube by the inherent elasticity of the spiral element Spiral elements; And
A first joint ring configured to secure the outer tube to the inner tube at a first axial end of the outer tube and having a first radial hole;
The helical element together with the inner tube and the outer tube form a helical flow path through the gap of the overlapping area, the helical flow path in fluid communication with the first radial hole,
heat transmitter.
The method of claim 20,
A second joint ring further configured to secure the outer tube to the inner tube at a second axial end of the outer tube, the second joint ring including a second radial hole, the spiral flow path being the A heat exchanger in fluid communication with the second radial hole.
The method of claim 20 or 21,
The first joint ring includes a central hole having a diameter substantially the same as the outer diameter of the inner tube, the first mating hole has a middle diameter of the diameter of the central hole and the diameter of the second mating hole, The diameter of the second mating hole is substantially the same as the outer diameter of the outer tube, wherein the central hole receives the inner tube and the second mating hole receives the outer tube therein.
The method of claim 22,
And the first radial hole is disposed in the first mating hole.
The method of claim 20 or 21,
And the outer tube is thermally separated from the helical element.

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