KR101065266B1 - Heat exchange pipe - Google Patents

Abstract

The present invention relates to a heat exchange tube, the heat exchange tube for recovering heat from the high-temperature exhaust gas passing through the outside, wound in a spiral shape along the outer circumferential surface in the longitudinal direction of the heat exchange tube, is formed to protrude from the outer circumferential surface A plurality of spiral protrusions disposed on the outer circumferential surface and spaced apart from each other, the plurality of grooves being formed; And a gas path portion provided by an outer circumferential surface between the neighboring spiral protrusion and the neighboring spiral protrusion, wherein the exhaust gas passes along a spiral gas path portion formed on the outer circumferential surface, thereby making contact with the exhaust gas. It is characterized by increasing.

Description

Heat exchanger tube {HEAT EXCHANGE PIPE}

The present invention relates to a heat exchanger tube, and more particularly, to a heat exchanger tube having a spiral protrusion on an outer circumferential surface thereof.

In general, the heat exchanger of a gas boiler discharges or inflows high temperature exhaust gas discharged from a burner into a spiral heat exchanger tube and contacts the exhaust gas and the heat exchanger tube so as to contact the hot exhaust gas and the low temperature heating water inside the heat exchanger tube. Heat exchange at the

In particular, the recovery rate of the latent heat of condensation of the exhaust gas through the heat exchanger tube increases as the contact time between the heat exchanger tube and the exhaust gas increases or the contact area increases, and studies to change the structure of the heat exchanger tube in order to increase the recovery rate have been actively conducted.

The conventionally applied condensation heat exchanger (WO / 2004/097310, published on Nov. 11, 2004) flattens the cross section of the heat exchanger tube and increases the number of rotational stacks of the heat exchanger tube around the burner to increase the contact area between the hot gas and the heat exchanger tube. To improve the heat exchange efficiency.

In another type of condensation heat exchanger, a plurality of heat exchanger tubes are installed in a plurality of heat exchanger tubes having different radii that surround the burner unit so that hot gases sequentially pass through multiple heat exchanger tubes to recover hot gas heat. Presented.

As described above, the conventional heat exchanger improves heat exchange efficiency by increasing the number of rotational stacks of the heat exchanger tube around the burner part or by arranging multiple heat exchanger tubes around the burner part to increase the contact area between the hot exhaust gas and the heat exchanger tube. Although using the method, this is a problem that the overall volume of the heat exchanger increases.

An object of the present invention is to solve such a conventional problem, to provide a heat exchange tube that can improve the heat exchange efficiency with the exhaust gas by increasing the contact area with the high temperature exhaust gas while reducing the overall volume of the heat exchange device. Is in.

In order to achieve the above object, the heat exchanger tube of the present invention is a heat exchanger tube that recovers heat from a high-temperature exhaust gas passing through the outside, and is wound in a spiral shape along the outer circumferential surface in the longitudinal direction of the heat exchanger tube. Is formed to protrude from the spaced apart from each other on the outer circumferential surface, a plurality of spiral protrusions are formed a plurality of grooves; And a gas path portion provided by an outer circumferential surface between the neighboring spiral protrusion and the neighboring spiral protrusion, wherein the exhaust gas passes along a spiral gas path portion formed on the outer circumferential surface, thereby making contact with the exhaust gas. It is characterized by increasing.

In the heat exchanger tube which concerns on this invention, Preferably, the said spiral protrusion part is provided 6 or more and 12 or less around the cross section cut along the direction which cross | intersects the longitudinal direction of a heat exchanger tube.

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In the heat exchanger tube according to the present invention, preferably, the spiral protrusion is formed to protrude from the outer peripheral surface to a height of 0.2 mm or more and 2.0 mm or less.

According to the heat exchange tube of the present invention, the path portion through which the hot exhaust gas passes is formed to be wound in a spiral shape along the outer circumferential surface of the heat exchange tube in the longitudinal direction of the heat exchange tube, thereby increasing the contact area between the hot exhaust gas and the heat exchange tube. The heat exchange efficiency of the exhaust gas and the heat exchanger tube can be improved.

In addition, according to the heat exchange tube of the present invention, by forming a plurality of fine grooves in the spiral protrusion forming the gas path portion, it is possible to increase the effective heat exchange area in contact with the exhaust gas and the heat exchange tube to improve the heat exchange efficiency.

Hereinafter, embodiments of the heat exchanger tube according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing an example of a heat exchanger using a heat exchanger tube according to an embodiment of the present invention, Figure 2 is an enlarged view of the heat exchanger tube of Figure 1, Figure 3 is a line III-III 'of FIG. 4 is an enlarged view of the spiral protrusion of the heat exchange tube of FIG. 2, and FIG. 5 is a view illustrating the flow of exhaust gas around the heat exchange tube of FIG. 2.

1 to 5, the heat exchanger 100 for a boiler heats the heating water by receiving heat from the burner, and includes a burner 110 and a heat exchanger tube 120.

The heat exchanger tube 120 is a circular pipe and is disposed around the burner part 110 that is a heat source while heating water flows therein, and includes a spiral protrusion 121 and a gas path part 122. In the case of the condensing boiler, the heat exchanger tube 120 is disposed around the burner unit 110 to absorb sensible heat and is also disposed at a position capable of absorbing the latent heat of condensation from the exhaust gas discharged to increase heat exchange efficiency. have.

As shown in FIG. 2, the spiral protrusion 121 is formed to protrude from the outer circumferential surface of the heat exchanger tube 120 and wound in a spiral shape along the outer circumferential surface of the heat exchanger tube in the longitudinal direction L of the heat exchanger tube. do. The spiral protrusion 120 may be formed to have an inclination angle θ of about 30 degrees or more and 60 degrees or less with respect to the longitudinal direction L of the heat exchanger tube.

The spiral protrusion 121 is formed at a height of about 0.2 mm or more and 2 mm or less from an outer circumferential surface of the heat exchanger tube, and is preferably formed at a height of 0.5 mm or more and 1.5 mm or less. When the heat exchanger tubes 120 are in close contact with each other and piped in the vertical direction or the horizontal direction, a gap is formed between the heat exchanger tubes 120 adjacent to each other by the protruding height of the spiral protrusion 121, and the exhaust gas is discharged through the gaps. Can pass. If the height H of the spiral protrusion 121 is less than 0.2 mm, it may hinder the flow of the exhaust gas. If the height H of the spiral protrusion 121 is greater than 2 mm, the heat exchange tubes adjacent to each other ( There is a fear that the gap between the 120 is so wide that the guide function of the gas path portion 122 to be described later is reduced.

Meanwhile, a plurality of spiral protrusions 121 are disposed on the outer circumferential surface of the heat exchanger, and are spaced apart from each other at predetermined intervals along the circumferential direction of the heat exchanger tube. As shown in FIG. 3, in the present embodiment, six pieces are provided based on a cross section cut along a direction intersecting the longitudinal direction L of the heat exchanger tube, and may be provided in six or more and twelve or less.

As shown in FIG. 4, a plurality of fine grooves 123 are formed in the spiral protrusion 121 to increase an effective heat exchange area in contact with the exhaust gas. By increasing the heat exchange area, the heat exchange efficiency between the high temperature exhaust gas and the heating water inside the heat exchange tube 120 may be improved.

The gas path part 122 is provided by an outer circumferential surface between the neighboring spiral protrusion 121 and the neighboring spiral protrusion 121, and the neighboring spiral protrusion 121 is the outer circumferential surface of the heat exchange tube. It is configured with the bottom surface. Like the spiral protrusion 121, the gas path 122 is formed to be wound in a spiral shape along the outer circumferential surface of the heat exchanger tube in the longitudinal direction L of the heat exchanger tube. Thus, as shown in Figure 5, when the hot exhaust gas passes around the heat exchange tube 120, the path of the exhaust gas is guided by the gas path portion 122, the exhaust gas in a diagonal direction, that is, heat exchange By inclining at an angle with the longitudinal direction L of the tube (in the direction of the arrow in FIG. 5), the contact area between the heat exchanger tube 120 and the exhaust gas may be increased, thereby improving heat exchange efficiency.

As the quantity of the spiral protrusion 121 formed on the outer circumferential surface of the heat exchanger tube and the quantity of the gas path portion 122 increase, the effective heat exchange area in contact with the high temperature exhaust gas increases, but when 13 or more gas path portions are provided, The gas does not pass in a spiral trajectory along the outer circumferential surface of the heat exchange tube, and proceeds in a direction substantially perpendicular to the longitudinal direction L of the heat exchange tube. Therefore, the contact time between the exhaust gas and the heat exchange tube 120 may decrease, and heat exchange efficiency may also decrease. On the other hand, when the quantity of the spiral protrusion 121 formed on the outer circumferential surface of the heat exchanger tube and the quantity of the gas passage 122 are five or less, the gas path portion guides the exhaust gas to pass through the spiral trace along the outer circumferential surface of the heat exchanger tube. Problems can occur that can't play a role faithfully. Therefore, the number of spiral protrusions 121 and the number of gas paths 122 formed on the outer circumferential surface of the heat exchanger tube are 6 or more and 12 or less, respectively, based on the cross section cut along the direction crossing the longitudinal direction of the heat exchanger tube. It is preferable to provide in the range.

The heat exchanger tube according to the present embodiment configured as described above is formed so as to spirally form a path portion through which the hot exhaust gas passes in a spiral shape along the outer circumferential surface of the heat exchanger tube in the longitudinal direction of the heat exchanger tube. By increasing the contact path and the contact area of the can be obtained an effect that can improve the heat exchange efficiency of the exhaust gas and the heat exchange tube.

In addition, the heat exchanger tube according to the present exemplary embodiment configured as described above may increase the effective heat exchange area between the exhaust gas and the heat exchanger tube to improve heat exchange efficiency by forming a plurality of fine grooves in the spiral protrusion forming the gas path portion. You can get the effect.

As shown in FIG. 4, the spiral protrusion according to the present embodiment is configured to have a square shape, but may have various shapes such as a polygonal shape or a round shape in addition to the square shape.

In the present embodiment, the grooves for extending the heat exchange area with the exhaust gas are formed in the spiral protrusion, but may be formed on the outer circumferential surface of the heat exchange tube.

Hereinafter, embodiments of a heat exchange tube unit using a heat exchange tube according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 6 is a diagram of an example of a heat exchange tube unit using the heat exchange tube of FIG. 2, FIG. 7 is an enlarged view of the heat exchange tube unit of FIG. 6, and FIG. 8 is a diagram illustrating an example of a heat exchange tube unit configured incorrectly.

6 to 8, members referred to by the same reference numerals as the members shown in FIGS. 1 to 5 have the same configuration and function, and detailed descriptions thereof will be omitted.

6 to 8, the heat exchange tube unit 220 according to the present embodiment uses a pair of heat exchange tubes formed so as to wind the spiral protrusion part and the gas path part in different directions, and includes the first heat exchange tube 230 and the first heat exchange tube 230. It includes a second heat exchange tube (240).

The first heat exchange tube 230 is, like the heat exchange tube shown in Figure 2, a plurality of spiral protrusions 121 are formed to protrude while wound in a spiral shape along the outer peripheral surface in the longitudinal direction (L) of the heat exchange tube and And a gas path portion 122 provided by the neighboring spiral protrusion 121 and an outer circumferential surface therebetween. As illustrated in FIG. 7, the first heat exchange tube 230 is formed such that the spiral protrusion 121 and the gas path portion 122 wind the outer circumferential surface of the heat exchange tube in the right-hand direction.

Similarly to the heat exchanger tube illustrated in FIG. 2, the second heat exchanger tube 240 includes a plurality of spiral protrusions 121 formed to protrude while being wound in a spiral shape along the outer circumferential surface in the longitudinal direction L of the heat exchanger tube. And a gas path portion 122 provided by the neighboring spiral protrusion 121 and an outer circumferential surface therebetween. As shown in FIG. 7, in the second heat exchange tube 240, the direction in which the spiral protrusion 121 and the gas path portion 122 are wound is opposite to the first heat exchange tube 230, and the spiral protrusion 121 is formed. And the gas path part 122 is formed to wind the outer circumferential surface of the heat exchanger tube in the direction of the left screw.

The heat exchange tube unit 220 of the present embodiment is characterized in that the first heat exchange tube 230 and the second heat exchange tube 240 are stacked in the vertical direction. When the first heat exchanger tube 230 and the second heat exchanger tube 240 are formed to be in contact with each other, the gas path portion 122 of the first heat exchanger tube at the point of contact with the gas path 122 The gas path part 122 of the second heat exchange tube may smoothly pass the exhaust gas passing between the first heat exchange tube 230 and the second heat exchange tube 240 by guiding the exhaust gas in the same direction.

Referring to FIG. 8, a pair of first heat exchange tubes 230 in which a gas path part 122 is formed in a right screw direction is stacked in a vertical direction. In the process of passing the exhaust gas between the upper first heat exchanger tube 230 and the lower first heat exchanger tube 230, the exhaust gas that hits the upper first heat exchanger tube 230 on the traveling path is the upper first heat exchanger tube 230. The traveling path is guided by the gas path part 122 of FIG. 2) and passes downward through the gaps of the heat exchange tubes while proceeding downward to the right as indicated by the arrow A1, and hits the lower first heat exchange tube 230 on the traveling path. The exhaust gas is guided by the gas path part 122 of the lower first heat exchanger tube 230 and passes through a gap between the heat exchanger tubes while traveling upward to the left side as indicated by the arrow A2. At this time, the exhaust gas passing through the gas path part 122 of the upper first heat exchange tube 230 and the exhaust gas passing through the gas path part 122 of the lower first heat exchange tube 230 collide with each other. The passage speed of the exhaust gas is lowered. The heat transfer coefficient (h) is proportional to the passage speed of the exhaust gas. Due to the low passage speed of the exhaust gas, there is a problem that the heat exchange efficiency of the exhaust gas and the heat exchange tube decreases.

On the other hand, as shown in Figure 7, the first heat exchange tube 230, the gas path portion 122 is formed in the right screw direction and the second heat exchange tube 240, the gas path portion 122 is formed in the left screw direction is up and down When stacked in contact with each other, the exhaust gas that strikes the upper first heat exchanger tube 230 on the traveling path is guided by the gas path part 122 of the first heat exchanger tube 230, and the arrow A1. The exhaust gas that passes through the gap of the heat exchange tubes while proceeding downward to the right side, and collides with the second heat exchange tube 240 on the lower side of the traveling path by the gas path 122 of the second heat exchange tube 240. The traveling path is guided and passes through the gaps of the heat exchange tubes while proceeding upward to the right as indicated by arrow A3. Therefore, the exhaust gas passing by the gas path part 122 of the first heat exchange tube 230 and the exhaust gas passing by the gas path part 122 of the second heat exchange tube 240 merge in the same direction. It is possible to prevent the passage speed of the exhaust gas from decreasing.

The heat exchanger tube unit according to the present embodiment configured as described above is arranged to contact a pair of heat exchanger tubes having gas path portions formed in different directions, whereby the passage speed of the exhaust gas passing through the gaps of the heat exchanger tubes is decreased. It can be prevented, and through this it is possible to obtain the effect of improving the heat exchange efficiency of the exhaust gas and the heat exchange tube.

9 is a view of another example of the heat exchange tube unit using the heat exchange tube of FIG. 2, FIG. 10 is a cross-sectional view taken along the line VII-VII 'of FIG. 9, and FIG. 11 is a view of the heat exchange tube unit of FIG. 9. The heat exchange state is displayed quantitatively, and FIG. 12 shows the heat exchange state of the conventional heat exchange tube unit quantitatively.

In FIGS. 9 to 12, members referred to by the same reference numerals as the members illustrated in FIGS. 1 to 8 have the same configuration and function, and detailed descriptions thereof will be omitted.

The heat exchange tube unit 320 according to the present exemplary embodiment may increase heat recovery from the exhaust gas by arranging the heat exchange tube to be wound in a spiral form with a different radius around the burner unit 110. A circumference portion 321 and a second circumference portion 322 are included.

As shown in FIG. 1, the first circumferential part 321 forms a first radius R1 based on the central axis C of the burner part and is wound around the first heat exchange tube 230. A second heat exchanger tube 240 is formed in a spiral form while forming a first radius R1 based on the central axis C of the burner part while contacting the upper or lower side of the first heat exchanger tube 230.

The second circumference portion 322 is formed to surround the first circumference portion 321 at the outside of the first circumference portion 321 around the burner portion 110. The second circumference portion 322 forms a second radius R2 larger than the first radius R1 based on the central axis C of the burner portion and is wound around the first heat exchange tube 230 and the first heat exchanger. A second heat exchanger tube 240 is formed to form a second radius R2 based on the central axis C of the burner and wound in a spiral form while contacting the upper or lower side of the first heat exchanger tube 230.

At this time, by communicating the heat exchange tubes 230 and 240 constituting the first peripheral portion 321 and the second peripheral portion 322 with each other, the first heat exchanger tube of the second peripheral portion 322 in which the low-temperature heating water is disposed outside It is heated while passing through the 230 and the second heat exchange tube 240, and then heated while passing through the first heat exchange tube 230 and the second heat exchange tube 240 of the first peripheral portion 321 disposed inside. do.

As shown in FIG. 10, when arranging the heat exchanger tubes of the first peripheral portion and the heat exchanger tubes of the second peripheral portion, the first heat exchanger tube 230 and the second heat exchanger tube 240 of the first peripheral portion 321 are disposed. Heat exchange of the first peripheral portion 321 so that the contacting position P1 and the center position P2 of the first heat exchange tube 230 or the second heat exchange tube 240 of the second peripheral portion 322 are horizontal. It is preferable to arrange the heat exchange tubes of the tubes and the second peripheral portion 322. Due to the arrangement state of the heat exchanger tube as the exhaust gas generated from the burner part 110 proceeds from the inside of the first circumference 321 to the outside of the second circumference 322, the path of the exhaust gas flows. It may be formed in a zigzag form (see arrows in FIG. 10). Therefore, since the traveling path of the exhaust gas passing through the first circumferential portion 321 and the second circumferential portion 322 is long, the contact area and the contact path of the exhaust gas and the heat exchange tube are increased, thereby improving heat exchange efficiency. .

11 is a quantitative display of the heat exchange state of the heat exchanger tube unit of the present embodiment, in which a heat exchanger tube having six spiral protrusions 121 and a gas path portion 122 are arranged in triple with different radii. Each circumference has a first heat exchange tube 230 having a gas path portion 122 formed in a spiral shape along the outer circumferential surface in the right-hand direction, and a second gas path portion 122 formed in a spiral shape along the outer circumferential surface in the left screw direction. The heat exchanger tube 240 is disposed to be in contact with the vertical direction.

12 is a quantitative display of the heat exchange state of a conventional heat exchanger tube unit, in which a circular heat exchanger tube having the same diameter as the heat exchanger tube of this embodiment and having no spiral protrusion and gas path portion is disposed in three. Here, the spacing between the heat exchange tubes is equal to the spacing between the heat exchange tubes of FIG. 11.

In the experimental examples of FIGS. 11 and 12, the temperature of the exhaust gas passing between the heat exchange tubes was 1073 K, and the flow rate was 75 m ³ / h. In addition, the temperature of the heating water conveyed through the heat exchanger tube was 300K, and the flow rate was 1L / min.

As a result of calculation using computational fluid dynamics, the total heat transfer amount of the heat exchange tube unit 320 of this embodiment of FIG. 11 was 5.95 kW, and the total heat transfer amount of the conventional heat exchange tube unit of FIG. 12 was 3.25 kW. It can be seen that the heat transfer amount of the heat exchange tube unit 320 composed of the heat exchange tube having the spiral protrusion part and the gas path part is about 80% higher than that of the conventional heat exchange tube unit.

In the heat exchanger tube unit according to the present embodiment configured as described above, by arranging several heat exchanger tubes around the burner part, the contact area and the contact path between the exhaust gas discharged from the inside of the heat exchanger to the outside and the heat exchanger tube are increased. Thus, an effect of improving heat exchange efficiency may be obtained.

The scope of the present invention is not limited to the above-described embodiments and modifications, but may be embodied in various forms of embodiments within the scope of the appended claims. Without departing from the gist of the invention claimed in the claims, it is intended that any person skilled in the art to which the present invention pertains falls within the scope of the claims described in the present invention to various extents which can be modified.

The national research and development project that supported this invention is a support project of "Ministry of Knowledge Economy", the project unique number is "MM9350", and the research project name is "Strategic technology development project, high efficiency eco-friendly condensing gas boiler development". System Integration and Development of Element Components ", and will be carried out from" November 1, 2006 to October 31, 2009 "under the supervision of" Korea Institute of Machinery and Materials ".

1 is a view showing an example of a heat exchanger using a heat exchanger tube according to an embodiment of the present invention,

2 is an enlarged view of the heat exchanger tube of FIG. 1,

3 is a cross-sectional view taken along line III-III 'of FIG. 2,

4 is an enlarged view of the spiral protrusion of the heat exchanger tube of FIG. 2;

5 is a view showing the flow of exhaust gas around the heat exchange tube of FIG.

6 is a view of an example of a heat exchanger tube unit using the heat exchanger tube of FIG. 2,

7 is an enlarged view of the heat exchanger tube unit of FIG. 6,

8 is a view showing an example of a misconfigured heat exchanger tube unit,

9 is a view of another example of a heat exchanger tube unit using the heat exchanger tube of FIG. 2,

10 is a cross-sectional view taken along the line VII-VII 'of FIG. 9,

11 is a quantitative display of the heat exchange state of the heat exchange tube unit of FIG.

12 quantitatively displays the heat exchange state of a conventional heat exchange tube unit.

<Description of the symbols for the main parts of the drawings>

100: heat exchanger 110: burner unit

120: heat exchange tube 121: spiral protrusion

122: gas path portion 220: heat exchange tube unit

230: first heat exchanger tube 240: second heat exchanger tube

Claims (4)

In the heat exchanger tube for recovering heat from the high-temperature exhaust gas passing through the outside, A plurality of spiral protrusions wound in a spiral shape along the outer circumferential surface in a length direction of the heat exchanger tube, protruding from the outer circumferential surface, and spaced apart from each other on the outer circumferential surface, the plurality of grooves being formed; And And a gas path portion provided by an outer circumferential surface between the neighboring spiral protrusion and the neighboring spiral protrusion. And wherein the exhaust gas passes along a spiral gas path formed on the outer circumferential surface, thereby increasing the contact area with the exhaust gas. The method of claim 1, The spiral protrusion, A heat exchanger tube, characterized in that 6 or more 12 is provided around the cross-section cut along the direction crossing the longitudinal direction of the heat exchanger tube. delete The method of claim 1, The spiral projection portion is formed to protrude from the outer peripheral surface to a height of 0.2 mm or more and 2.0 mm or less.

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