This Nonprovisional application claims priority under 35 U.S.C. § 119(a) on patent application No(s). 10-2003-0061151 filed in KOREA on Sep. 2, 2003, the entire contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a heat exchanger, and more particularly, to a heat exchanger that is designed to reduce flow-resistance of air introduced into a fin collar region of a corrugate fin and to provide a uniform airflow speed distribution to the fin.
2. Description of the Related Art
Generally, a heat pump type air conditioner is operated in a cooling mode when an indoor temperature is higher than a predetermined level and is operated in a heating mode when the indoor temperature is lower than the predetermined level. At this point, when the air conditioner is operated in the heating mode, a heat exchanger of the air conditioner functions as an evaporator.
Referring to
In the cooling mode, refrigerant gas pumped out from a compressor 1 is separated from oil while passing through an oil separator 2, which is then directed to an outdoor heat exchanger 4 through a four-way valve 3. The refrigerant gas directed to the outdoor heat exchanger is phase-transited into a low-temperature low-pressure state while passing through an expansion valve 5 and is then directed to an indoor heat exchanger 6. The refrigerant gas vaporized in the indoor heat exchanger 6 is heat-exchanged with indoor air and is then directed to an accumulator 7 through the four-way valve 3. The refrigerant gas directed to the accumulator 7 is directed into the compressor 1 for the same circulation.
In a heating mode, the refrigerant gas pumped out from the compressor 1 is separated from oil while passing through the oil separator 2, which is then directed to the indoor heat exchanger 6 through the four-way valve 3 to thereby be condensed to heat-exchange with indoor air. The condensed refrigerant gas is then changed into a low-temperature low-pressure state while passing through the expansion valve 5 and is vaporized while passing through the heat exchanger 4. The vaporized refrigerant gas is directed to the accumulator 7 through the four-way valve 3. The refrigerant gas directed to the accumulator 7 is directed into the compressor 1 for the circulation.
Referring to
At this point, the outdoor air discharged by the blower fan 9 passes through an air passage defined between flat fins 11 fixed on tubes 10. In the heating mode, frost is formed on the surfaces of the fins 11 fixed on the tube 10. Here, the frost 12 formed on the flat fins 11 is relatively thick at the front end of the flat fin 11 where a relatively large amount of air flows, and the thickness of the frost 12 is gradually reduced as it goes toward a rear end of the flat fin 11.
The heat exchangers 8 are classified into several types according to a type of cooling fin arranged on the tubes. Most widely used is a corrugate fin type.
Referring to
The fin 110 includes peak and valley portions 112 and 114 that are alternately formed on a region, where the tubes 130 are not penetrating, and connected to each by longitudinal inclined sections, fin collars 116 through which the tubes 130 are inserted, longitudinal axes of the tubes being perpendicularly penetrating a longitudinal centerline of the fin 110, and seat portions 118 for supporting the fin collars 116.
The heat exchanger having such corrugate fins will be described more in detail hereinafter with reference to
Referring to
Each of the fins 110 has a plurality of donut-shaped flat portions and a plurality of longitudinal inclined sections that are defined by the W-shape having a plurality of the peak and valley portions 112 and 114. The fins 110 are installed on the tubes 130 in a longitudinal direction of the tubes 130, being spaced away from each other at a predetermined distance.
Referring to
That is, each of the fins 110 installed on the tube 130 has two peak portions 112a and 112b and three valley portions 114a, 114b and 114c, which are alternately disposed and connected by inclined sections. The shape of the fin 110 is symmetrical based on the longitudinal center valley portion 114b. Central axes of the tube 130 pass through the longitudinal center valley portion 114b.
The fin 110 is provided with a plurality of tube insertion holes 116a, whose central axes correspond to the respective central axes of the tubes 130. The fin collars 116 are elevated from the fin 110 to define the tube insertion holes 116a through which the tubes 130 are inserted. The tube 130 surface-contacts an inner circumference of each fin collar 116. The seat portion 118 is formed around a lower end of an outer circumference of the fin collar 116 to support the fin collar 116 and to allow air to flow in the form of enclosing the tube 130 and the fin collar 116.
An inclined portion 120 is formed on the fin 110 around the seat portion 118 to prevent the air flowing around the tube 130 from getting out of a circumference of the tube 130. The inclined portion 120 is inclined upward from the seat portion 18 to the peak portions 112.
In addition, the seat portion 118 is located on a horizontal level identical to that where the valley portions 114 are located. Heights and depths H1 of the peak and valley portions 112 and 114 are identical to each other. In addition, the inclined angles of the longitudinal inclined sections connecting the valley portions to the peak portions are also identical to each other.
When the air is introduced into the heat exchanger 101, since the seat portions 118 and the valley portions 114 are located on an identical horizontal plane, the air flowing around the tubes cannot reach the rear ends of the tubes. In addition, the growth of frost formed on an outer surface of the fin 110 is proportional to an amount of a heat transfer on the outer surface of the fin 110. The airflow speed is increased at the fin regions between the tubes, thereby forming a high-speed airflow. As a result, the heat transfer coefficient is increased and the frost layer is quickly grown on the surface of the fin 110 as shown in
When the frost layer is grown on the surface of the fin 110, since the distance between the adjacent fins 110 is reduced, an air passage area is also reduced. By the reduced area, the airflow speed is increased, as the result of which the pressure drop of the air is increased in the form of a parabola as time elapses and the heat transfer amount of the heat exchanger is also greatly reduced.
In addition, the air flowing around the tubes is accumulated at the rear ends of the tubes, deteriorating the heat transfer efficiency. That is, since the seat portions and the valley portions are located on the identical horizontal plane, the air cannot sufficiently reach the rear ends of the tubes. As a result, a wake region where the air is accumulated is formed on the rear ends, thereby deteriorating the heat transfer efficiency.
Therefore, there is a need for guiding high-speed airflow up to the rear ends of the tubes where the wake region is formed.
Accordingly, the present invention is directed to a heat exchanger that substantially obviates one or more problems due to limitations and disadvantages of the related art.
A first object of the present invention is to provide a heat exchanger that can reduce the wake region formed in a rear end of a tube by opening front and rear portions of a seat portion formed around a lower end of an outer circumference of a fin collar, thereby solving the accumulation problem of the air at the wake region and reducing the airflow-resistance.
A second object of the present invention is to provide a heat exchanger having a seat portion formed around a lower end of an outer circumference of a fin collar and provided with opened front and rear portions to provide a uniform airflow speed distribution through an overall surface of the fin, thereby improving the heat exchange efficiency.
A third object of the present invention is to provide a heat exchanger that can improve the heat exchange efficiency by forming a longitudinal center valley to be higher than a seat portion to enlarge an air passage area defined between the fins.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, there is provided a heat exchanger comprising a plurality of tubes through which refrigerants flow, the tubes being spaced away from each other at a predetermined distance; and a plurality of fins spaced away from each other at a predetermined distance, each of the fins having fin collars through which the tubes are perpendicularly inserted, seat portions each concentrically formed around outer circumferences of the fin collars and provided with laterally-opened front and rear portions, more than two peak portions, and more than two valley portions, the peak and valley portions being alternately disposed to provide airflow variation.
According to another aspect of the present invention, there is provided a heat exchanger comprising a plurality of tubes through which refrigerants flow, the tubes being spaced away from each other at a predetermined distance; and a plurality of fins spaced away from each other at a predetermined distance, each of the fins comprising first airflow guide means formed in a flat base to guide air induced into a fin collar region through which the tubes are perpendicularly inserted and second airflow guide means having peak and valley portions that are alternately disposed to provide airflow variation.
According to still another aspect of the present invention, there is provided a heat exchanger comprising at least two rows of tubes through which refrigerant flows, the tubes being disposed in a zigzag-shape; and a plurality of fins through which the tubes perpendicularly penetrate, wherein each of the fins comprises first airflow guide means for guiding air flowing around the tube up to a rear end of the tube with a uniform airflow speed distribution, the first airflow guide means comprising two arc-shaped flat bases that are symmetrically disposed around the tube; and second airflow guide means for providing airflow variation, the second airflow guide means comprising peak and valley portions and inclined sections connecting the peak and valley portions.
It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the present invention as claimed.
The accompanying drawings, which are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the present invention and together with the description serve to explain the principle of the present invention. In the drawings:
Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
Referring to
As shown in
That is, each of the fins 210 has the first and second peak potions 212 (212a and 212b) and the first, second and third valley portions 214 (214a, 214b and 214c). The peak and valley portions 212 and 214 are alternately formed and connected to each other by longitudinal inclined sections.
As shown in
The inclined portion 220 is formed extending from the outer circumference of the seat portion 218.
In order to provide airflow variation, a depth of the second valley portion 214b is lower than those of the first and third valley portions 214a and 214c.
The heat exchanger of the present invention will be described more in detail in conjunction with the accompanying drawings.
As shown in
Each of the fins 210 is divided into fin collar regions through the tubes 230 penetrate and inclined section regions defined between the fin collar regions. The peak and valley portions are formed in the inclined section regions.
The depth and heights of the valley and peak portions 214 and 212 are designed to be different from each other to provide the airflow variation.
Referring to
That is, the fin 210 is designed to be symmetrical with reference to the center valley portion 214b. The number of peak and valley portions may be varied.
As shown in
In addition, the fin collars 216 are elevated to a predetermined height, defining tube insertion holes 216a through which the tubes are inserted. The height of the fin collar 216 may be higher or lower than the peak portions 212.
In order to minimize the airflow-resistance, the seat portion 218 formed around the lower end of the fin collar 216 is formed to be flat having a horizontal plane identical to or lower than that where the valley portions 214a and 214b are located.
As a modified example, heights and depths of the peak portions 212 and the valley portions 214 may be designed to be different from each other. Furthermore, the number of the peak portions 212 and the valley portions 214 are preferably over 2 and 3. Fins are arranged in two or more rows for disposing tubes in a zigzag structure.
As another modified example, in order to increase the airflow speed along the fins, the heights of the peak portions may be gradually reduced as they go to the longitudinal centerline of the fin, or the depth of the valley portions maybe gradually reduced as they go to the longitudinal centerline of the fin.
Meanwhile, as shown in
That is, the seat portion 218 is designed such that the air is induced to the fin collar 216 through which the tube is inserted without receiving any flow-resistance and is then, after it is heat-exchanged with the tube, exhausted without receiving any resistance.
That is, bases of the inlet and outlet channels 218a and 218c and the airflow guide channel 218b are located on an identical horizontal plane. The inlet and outlet channels 218a and 218c are formed in a straight channel type to allow the air to straightly flow and the airflow guide channel 218b is formed in a circular channel type to allow the air to flow to the outlet channel 218c along a gentle curved line.
In addition, the inlet and outlet channels 218a and 218c are designed having a width less than an outer diameter of the fin collar, but equal to or greater than that of the airflow guide channel 218b. Therefore, the inclined portions 220 defining an outer wall of the seat portion 218 have a predetermined inclined angle, connecting the seat portion 218 to the peak and valley portions 212 and 214.
The inclined portions 220 includes straight guide sections 220a and 220c defining sidewalls of the inlet and outlet channels 218a and 218b and arc-shaped guide sections 220b defining a sidewall of the airflow guide channel 218b to allow the air to flow along arc-shaped lines.
Accordingly, the inlet and outlet channels 220a and 220c allow the air to straightly flow to maintain its flow speed, while preventing the air from getting out of the fin collar region.
The arc-shaped guide sections 220b are inclined at a predetermined angle, defining the sidewall of the airflow guide channel 220b to guide the air to flow along the arc-shaped lines without getting out of the fin collar region. To this end, the airflow guide channel 218b is connected to the peak and valley portions 212a, 212b and 214b by the arc-shaped guide sections 220b having a curvature corresponding to an outer circumference of the seat portion 218
When high-speed air is induced into the seat portion 218, the air flows up to the rear end of the tube along the straight guide sections 220a and the curved guide section 220b. At this point, the rear straight guide sections 220a prevent the high-speed air from being accumulated at the rear end of the tube, thereby guiding the high-speed air to the next tube. That is, the flat base air inlet and outlet channels and the flat base airflow guide channel allow the air to flow up to the rear end of the tube at a high-speed, while going around the tube.
In addition, the inclined portions 220 connecting the seat portion 218 to the center valley portion 214b functions as a guider for guiding the air going around the tube to flow up to the rear end of the tube. The air flowing to the rear end of the tube agitates air accumulated on the rear end of the tube, thereby reducing the wake region formed on the rear end of the tube, which has a relatively low heat transmission efficiency.
In addition, the air inlet and outlet channels 218a and 218c allow the air flowing around the tube to effectively flow up to the rear end of the tube.
That is, since the bases of the air inlet and outlet channels 218a and 218c are located on a horizontal plane identical to or lower than that where the base of the airflow guide channel 218b are formed, the airflow-resistance that may occur while the air passes through the seat portion 218 is minimized. Likewise, the airflow-resistance occurring when the air flowing around the tube flows to the air outlet channel 218 can be also minimized. Therefore, The air can flow with the minimized airflow-resistance in the current row of fins, which is then directed to the next row of fins, minimizing the deterioration of the heat exchange efficiency.
As described above, the fin 210 is designed such that the depth of the longitudinal center valley portion is lower than those of other valley portions, the lateral front and rear sides of the seat portion of the fin collar area are opened, and the base of the seat portion is formed to be lower than the center valley portion. As a result, the flow variation of the air passing between the fins is increased when compared with the conventional art, thereby reducing the pressure drop for the high-speed airflow and increasing the heat transfer efficiency.
Furthermore, even when the fin is formed in a dual fin structure as shown in
When the air is introduced into a space defined between the fins, since the air flows around the tube with the increased flow speed by a small gap defined by the tubes, the air pressure may be dropt, increasing the airflow-resistance.
However, as shown in
As described above, the heat exchanger of the present invention has an advantage of reducing the wake region formed on the lateral rear end of the fin when the intake air flows around the fin collar area.
As the wake region is reduced, the air accumulation problem can be solved, and the airflow-resistance is reduced. Furthermore, since the airflow speed distribution at the next row of the fins becomes uniform, the heat exchange efficiency of the next row of the fins can be improved.
It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
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