JP2010014283A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent flowing-down of dew condensation water generating on outer faces of pipe plates and including a rust component at an upper side, onto a heat transfer pipe at a lower side, to suppress progress of corrosion. <P>SOLUTION: A cross fin coil type heat exchanger is composed of the copper heat transfer pipe composed of straight pipe sections and a U-shaped pipe section connecting end sections of the straight pipe sections, a number of heat transfer fins fitted to the straight pipe sections of the heat transfer pipe in parallel with each other at prescribed pitches, and a pair of metallic pipe plates positioned at both sides of the number of heat transfer fins and fitted to the straight pipe sections of the heat transfer pipe. The outer faces of the pair of pipe plates are provided with water guides blocking the water flow between upper and lower outer pipe sections of the plurality of heat transfer pipes, and guiding the water flow to a front end side or a rear end side of the pipe plates. As a result, flowing-down of the dew condensation water generating on the outer side face of each pipe plate at the upper side to the heat transfer pipes at the lower side can be prevented, and the progress of corrosion can be suppressed as small as possible. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to the structure of a heat exchanger such as an indoor unit for an air conditioner.

  For example, as a heat exchanger for an air conditioner indoor unit, a cross fin coil type air heat exchanger is generally adopted, and the condensed water generated on the surface of the heat exchanger (evaporator) during cooling operation is caused by gravity. It flows down along the fin surface of the heat exchanger, is collected in a drain pan portion provided below the heat exchanger, and is discharged outside the room (see, for example, Patent Document 1).

  The structure of a conventional indoor unit for an air conditioner configured with such a heat exchanger is shown in FIGS.

  That is, in this conventional example, the air heat exchanger 3 that extends straight from the lower side to the upper side and the upper side is slightly inclined toward the downstream side of the air flow and is erected on the drain pan 10 and the cross flow fan 4 are provided. The wall-mounted air conditioner indoor unit 1 is sucked and blown obliquely downward, and reference numeral 2 denotes a cassette-type main body casing of the wall-mounted air conditioner indoor unit 1. The main body casing 2 is installed on the wall surface of the wall 6 so that the back panel portion thereof is in contact with the wall 6 of the room.

  An air suction port 2 a having a filter 5 is provided on the front side of the main casing 2, and an air heat exchanger 3 and a cross flow fan 4 are sequentially provided in the inner air passage 2 b.

  For example, as shown in FIGS. 10 and 11, the air heat exchanger 3 includes a large number of straight pipe portions 33 a that are arranged in two rows in the front-rear direction from the upstream to the downstream of the air flow and are alternately shifted in position. , 33a... And copper heat transfer tubes 33, 33... Composed of U-shaped tube portions 33b, 33b. , Heat transfer fins 32, 32,... Arranged in parallel with a predetermined pitch with respect to the straight pipe portions 33a, 33a,. A pair of metal tube plates 31 fitted on the straight pipe portions 33a, 33a,... Of the heat transfer tubes 33, 33,. , 31 and a cross fin coil type heat exchanger.

  The cross flow fan 4 is provided on the downstream side of the air flow. The cross flow fan 4 blows temperature-controlled air diagonally downward from an air outlet 2d at the bottom of the front surface of the main casing 2 through a temperature-control air passage 2c having a scroll structure.

  Therefore, in the case of this configuration, for example, during the cooling or heating operation, when the cross flow fan 4 that is a blowing means is driven, indoor air is sucked from the air suction port 2a and is passed through the air heat exchanger 3. The temperature-controlled air (cold air or warm air) that is uniformly and effectively heat-exchanged with low-pressure loss is blown out from the air outlet 2d below the front face, and the temperature-controlled air descends downward to the user. A comfortable cooling or heating air-conditioning environment is realized.

  In the air heat exchanger 3 applied to such a wall-hanging indoor unit for an air conditioner, the heat transfer fins 32, 32 are used particularly during cooling operation in which the heat exchanger 3 serves as an evaporator. The moisture in the air condenses on the heat transfer surface, and a lot of condensation occurs on the heat transfer surface, and they gather and flow downward.

  And it collects in the drain pan 10 part provided in the downward direction of the heat exchanger 3, and is discharged | emitted outside the room.

Japanese Patent Laying-Open No. 2004-353914 (Specification page 1-13, FIG. 1-4)

  By the way, in the heat exchanger comprised from the above copper heat transfer tubes, heat transfer fins, and tube plates, the outside of the tube plate that is not covered with the heat transfer fins, that is, the outer end of the straight tube portion of the heat transfer tubes In general, the U-shaped tube portion and the header portion are used with the heat transfer tube bare. It is known that a copper tube exhibits excellent corrosion resistance by forming a passive film (such as copper oxide) on the surface of the copper tube in a normal environment.

  However, when foreign matter or other metal corrosion scales adhere to the surface of the metal and are placed in an environment where moisture can easily enter the gap, corrosion sometimes occurs under the foreign matter. This form of corrosion is called oxygen concentration cell corrosion. In order to reduce the amount of copper used in recent years, the copper heat transfer tube 33 tends to be thinner, and when such oxygen concentration cell corrosion occurs, the tube thickness penetrates in a short period of time, causing the refrigerant to flow. Leakage not only makes the air conditioner inoperable, but also causes global warming due to leakage of CFC refrigerant.

  Therefore, in order to sufficiently exhibit the corrosion resistance of the copper heat transfer tube 33, it is preferable to prevent foreign matters and corrosion scales from adhering to the surface.

  When the state of the tube plate 31 of the heat exchanger for indoor air conditioners that has been used for many years is observed, for example, as shown in FIG. 12A, the tube plate 31 generated at the contact portion between the upper heat transfer tube 33 and the tube plate 31. Corrosion products (such as iron rust) Z hang down along with the dew condensation water and are likely to accumulate on the surface of the heat transfer tube 33 on the lower side. And since the electric corrosion mentioned above tends to produce in the contact part of the heat exchanger tube 33 and the tube sheet 31, the tube sheet 31 side corrodes and iron rust generate | occur | produces. And if corrosion products Z, such as iron rust, accumulate on the surface of heat exchanger tube 33, it will become easy to generate oxygen concentration cell corrosion on the surface of heat exchanger tube 33 in the lower part. In addition, corrosive substances such as chlorine and sulfur contained in the condensed water are concentrated in the iron rust, further forming a corrosive environment.

  As a result, the corrosion progresses, and as shown in FIG. 12B, it penetrates the tube wall 33d in a short period of time (see section A in FIG. 12B), and the refrigerant in the refrigerant passage 33c Leakage not only makes the air conditioner inoperable, but also causes global warming due to leakage of CFC refrigerant.

  The present invention has been made to solve such a problem, and iron rust generated at the contact portion between the upper heat transfer tube and the tube sheet on the outer surface of the tube plate is condensed on the lower heat transfer tube. A heat exchanger that prevents corrosion as described above by providing a water guide that shuts off the flow of condensed water when it drips with water and guides it to the end (front end or rear end) side of the tube sheet. It is intended to provide.

  In order to achieve the above object, the present invention is configured with the following problem solving means.

(1) Invention of Claim 1 The heat exchanger of this invention is a copper heat-transfer tube which consists of a straight pipe part and the U-shaped pipe part which connects the edge parts of this straight pipe part, and the said straight pipe part of this heat transfer tube A plurality of heat transfer fins arranged side by side at a predetermined pitch, and a pair of metal fittings fitted on the straight pipe portions of the heat transfer tubes located on both sides of the plurality of heat transfer fins A cross fin coil type heat exchanger composed of a tube plate, on the outer surface of the pair of tube plates, blocking the flow of water between the upper and lower outer tube portions of the plurality of heat transfer tubes, And the water guide which guides to the front-end side or rear-end side of the said tube sheet is provided, It is characterized by the above-mentioned.

  According to such a configuration, the water guide blocks the flow of water from the upper side of the plurality of heat transfer tubes to the lower side heat transfer tube, and is guided to the front end side or the rear end side of the tube plate. Therefore, it is avoided that the condensed water containing the rust component generated on the outer surface of each tube sheet flows down on the lower heat transfer tube, and the above-described corrosion is prevented.

(2) Invention of Claim 2 The heat exchanger of this invention is the structure of the said invention of Claim 1, The water guide is a hook-shaped member provided in the tube-sheet outer side surface, It is characterized by the above-mentioned.

  According to such a configuration, the flange-like member provided on the outer surface of the tube sheet blocks the flow of water from the upper side to the lower side of the plurality of heat transfer tubes, and at the front end side or the rear side of the tube plate. Since it is guided to the end side, it is avoided that the condensed water containing the rust component generated on the outer surface of each tube sheet flows down onto the lower heat transfer tube, and the progress of corrosion is prevented as much as possible.

(3) Invention of Claim 3 The heat exchanger of this invention is the structure of the invention of the said Claim 2, The hook-shaped member cuts and raises a part of tube sheet, It is characterized by the above-mentioned. .

  According to such a configuration, the flow of water from the upper side to the lower side of the plurality of heat transfer tubes is blocked by the hook-shaped member provided on the outer surface of the tube plate by cutting and raising a part of the tube plate. Since it is guided to the front end side or the rear end side of the tube sheet, it is avoided that the condensed water containing the rust component generated on the outer surface of each tube sheet flows down on the lower heat transfer tube. In addition, the progress of corrosion is prevented.

(4) Invention of Claim 4 In the heat exchanger of this invention, in the configuration of the invention of Claim 2, the flange-shaped member is formed by rib-processing a part of the tube sheet. Yes.

  According to such a configuration, the flow of water from the upper side to the lower side of the plurality of heat transfer tubes is blocked by the hook-shaped member provided on the outer surface of the tube plate by rib-processing a part of the tube plate. In addition, since it is guided to the front end side or the rear end side of the tube sheet, it is possible to prevent the condensed water containing rust components generated on the outer surface of each tube sheet from flowing down onto the lower heat transfer tube. In particular, the progress of corrosion is prevented.

(5) Invention of Claim 5 The heat exchanger of this invention is the structure of the said invention of Claim 2, The hook-shaped member is formed by attaching a member different from a tube sheet, It is characterized by the above-mentioned. .

  According to such a configuration, the flow of water from the upper side to the lower side of the plurality of heat transfer tubes is blocked by the flange-like member on the outer surface of the tube plate formed by attaching a member different from the tube plate. In addition, since it is guided to the front end side or the rear end side, it is avoided that the condensed water containing the rust component generated on the outer surface of each tube sheet flows down on the lower heat transfer tube, and is corroded as much as possible. Progress is prevented.

(6) Invention of Claim 6 The heat exchanger of this invention is the structure of the invention of said Claim 1, The water guide is a slit formed in a part of tube sheet, It is characterized by the above-mentioned.

  According to such a configuration, the slit formed in a part of the tube plate blocks the flow of water from the upper side to the lower side of the plurality of heat transfer tubes, and the front end side or the rear end of the tube plate. Since it is guided to the side, it is avoided that the dew condensation water containing the rust component generated on the outer surface of each tube sheet flows down onto the lower heat transfer tube, and the progress of corrosion is prevented.

(7) Invention of Claim 7 The heat exchanger of this invention is the structure of the said invention of Claim 1, The water guide is a concave groove formed in a part of the tube sheet.

  According to such a configuration, the concave groove formed in a part of the tube plate blocks the flow of water from the upper side of the plurality of heat transfer tubes to the lower side, and the front end side of the tube plate or Since it is guided to the rear end side, it is avoided that the condensed water containing the rust component generated on the outer surface of each tube sheet flows down on the lower heat transfer tube, and the progress of corrosion is prevented.

  As a result, according to the present invention, since the conventional oxygen concentration cell corrosion does not easily occur on the surface of the heat transfer tube, the corrosion resistance of the heat transfer tube and thus the heat exchanger is greatly improved.

(Best Embodiment 1)
1 and 2 show the configuration and operation of a heat exchanger for an air conditioner according to the first preferred embodiment of the present invention.

  That is, this air conditioner heat exchanger is configured to be suitable for a heat exchanger for an air conditioner indoor unit, similar to the conventional one already described, and the straight pipe portions 33a, 33a,. And copper heat transfer tubes 33 formed of U-shaped tube portions 33b, 33b, which connect the outer end portions of the straight tube portions 33a, 33a,. ... And a plurality of heat transfer fins 32, 32... Arranged in parallel to the straight pipe portions 33 a, 33 a. And a pair of left and right metals fitted to the straight pipe portions 33a, 33a,... Of the heat transfer tubes 33, 33,. It consists of tube plates 31, 31 made of (ferrous metal).

  Further, the pair of left and right tube plates 31, 31 includes a plurality of heat transfer tubes 33, 33..., Upper and lower straight tube portions 33 a, 33 a. Are provided with a bowl-shaped water guide member (edge) 35, 35... That blocks the flow of water to the tube plate 31 and leads to the front end side 31 a (or the rear end side 31 b) of the tube sheet 31.

  In this embodiment, for example, as shown in FIG. 2, the bowl-shaped water guide members 35, 35... Have a predetermined angle from the rear end 31 b side to the front end 31 a side on the outer surface of the tube plate 31. It is a bowl-shaped piece provided in an inclined manner, and is formed by cutting a part of the tube sheets 31, 31. Reference numerals 35a, 35a,... Denote slit-like cut and raised holes.

  According to such a configuration, the tube plates 31, 31 are cut and raised at right angles to form the bowl-shaped water guide members 35, 35... And the cut and raised holes 35a, 35a. The flow of water W, W... From the upper side to the lower side of each of the plurality of heat transfer tubes 33, 33... Is cut off, and the front end side 31 a (or rear end side) of the tube plates 31, 31. 31b) is smoothly guided so that the condensed water containing the upper rust component generated on the outer surface of each tube plate 31, 31 is prevented from flowing down to the lower heat transfer tubes 33, 33. And the progress of corrosion is prevented as much as possible.

  As a result, the conventional oxygen concentration cell corrosion is unlikely to occur on the surfaces of the heat transfer tubes 33, 33..., So that the corrosion resistance of the heat transfer tubes 33, 33.

(Best Mode 2)
Next, FIGS. 3 and 4 show the configuration of the heat exchanger for an air conditioner according to the second preferred embodiment of the present invention.

  The heat exchanger according to this embodiment has a configuration of a cross fin coil heat exchanger similar to that of the above-described first embodiment, except that bowl-shaped water guide members (edges) 35, 35. For example, as shown in FIGS. 3 and 4, rib pieces 36, 31 are formed by ribbing a part of the tube plates 31, 31 in a U-shaped cross section. It is characterized by being formed as 36.

  According to such a configuration, a plurality of the above-mentioned plurality of tube plates 31, 31 are formed by rib-shaped rib pieces 36, 36. The flow of the water W, W... From the upper stage side to the lower stage side is interrupted and guided to the front end 31 a side (or the rear end 31 b side) of the tube plates 31, 31. Therefore, it is avoided that the dew condensation water containing the rust component on the upper stage generated on the outer surface of each tube plate 31, 31 flows down and accumulates on the heat transfer pipes 33, 33 on the lower stage. Progress is prevented.

  As a result, the conventional oxygen concentration cell corrosion is unlikely to occur on the surfaces of the heat transfer tubes 33, 33..., So that the corrosion resistance of the heat transfer tubes 33, 33.

(Best Mode 3)
Next, FIG. 5 and FIG. 6 show the configuration of the heat exchanger according to the third preferred embodiment of the present invention.

  The heat exchanger of this embodiment has the same configuration of the cross fin coil type heat exchanger as that of the above-mentioned embodiment 1, but its bowl-shaped water guide members (edges) 35, 35. Instead of the cut-and-raised pieces, the projections are formed as separate members (for example, synthetic resin materials) 37, 37... Attached to the side surfaces of the tube plates 31, 31.

  According to such a configuration, the plurality of heat transfer tubes 33, 33... From the upper stage side to the lower stage side by the projecting members 37, 37. Since the flow of the water W, W... Is blocked and guided to the front end 31a side (or the rear end 31b side) of the tube plates 31, 31, the upper stage generated on the outer surface of each tube plate 31, 31. It is avoided that the condensed water containing the rust component on the side flows down and accumulates on the lower heat transfer tubes 33, 33, and the progress of corrosion is prevented as much as possible.

  As a result, the conventional oxygen concentration cell corrosion is unlikely to occur on the surfaces of the heat transfer tubes 33, 33..., So that the corrosion resistance of the heat transfer tubes 33, 33.

  Further, in the case of such a configuration, the projecting members 37, 37... Can be easily attached by a method such as adhesion, so that the tube plate 31, Compared with the case where part of 31 itself is cut and raised, or rib processing is performed, formation is easy and can be realized at low cost.

(Fourth Embodiment)
Next, FIGS. 7 and 8 show the configuration of the heat exchanger according to the fourth embodiment of the present invention.

  In the heat exchanger of this embodiment, in the configuration of the cross fin coil heat exchanger similar to that of the first embodiment, the water guide member that performs the above-described function is a part of the tube plates 31, 31. Further, it is characterized by comprising slits 38, 38... Inclined from the rear end 31b side to the front end 31a side (or vice versa).

  According to such a configuration, water from the upper side to the lower side of the plurality of heat transfer tubes 33, 33... Is formed by the slits 38, 38. Since the flow of W, W... Is interrupted and guided to the front end 31a side (or rear end 31b side) of the tube plates 31, 31, the upper stage generated on the outer surface of each tube plate 31, 31. It is avoided that the condensed water containing the rust component on the side flows down and accumulates on the lower heat transfer tubes 33, 33, and the progress of corrosion is prevented as much as possible.

  As a result, the conventional oxygen concentration cell corrosion is unlikely to occur on the surfaces of the heat transfer tubes 33, 33..., So that the corrosion resistance of the heat transfer tubes 33, 33.

  Further, in such a configuration, it is only necessary to punch the slit, so that a part of the tube sheet 31, 31 itself is cut up and processed as in the first and second embodiments. Compared with the case of rib processing, it is relatively easy to form and can be realized at a relatively low cost.

(Other embodiments)
The water guide portion similar to that in each of the above embodiments has, for example, an inclined groove having a V-shaped or U-shaped cross section on the outer surface of the tube plates 31, 31 in addition to the above-described configuration. Also good.

  The subject of the present invention is not limited to an indoor unit, but can also be applied to a heat exchanger for an outdoor unit.

It is a side view which shows the structure of the tube sheet part of the heat exchanger for air conditioners which concerns on the best Embodiment 1 of this invention. It is a longitudinal cross-sectional view (cut | disconnected in the heat exchanger tube part of the front row or back row) of the same heat exchanger. It is a side view which shows the structure of the tube sheet part of the heat exchanger for air conditioners which concerns on the best Embodiment 2 of this invention. It is a longitudinal cross-sectional view (cut | disconnected in the heat exchanger tube part of the front row or back row) of the same heat exchanger. It is a side view which shows the structure of the tube sheet part of the heat exchanger for air conditioners which concerns on the best Embodiment 3 of this invention. It is a longitudinal cross-sectional view (cut | disconnected in the heat exchanger tube part of the front row or back row) of the same heat exchanger. It is one side view which shows the structure of the tube sheet part of the heat exchanger for air conditioners which concerns on the best Embodiment 4 of this invention. It is a longitudinal cross-sectional view (cut | disconnected in the heat exchanger tube part of the front row or back row) of the same heat exchanger. It is a longitudinal cross-sectional view which shows the structure of the heat exchanger for air conditioners which concerns on a prior art example. It is a perspective view which shows the structure of the heat exchanger for air conditioners which concerns on the same prior art example. It is a side view of the tube sheet part of the conventional heat exchanger. It is a longitudinal cross-sectional view (cut by the heat exchanger tube fitting part of the front row or back row) which shows the corrosion progress state of the heat exchanger principal part.

Explanation of symbols

  31 is a tube plate, 33 is a heat transfer tube (whole), 33a is a straight tube portion of the heat transfer tube 33, 33b is an outer end U-shaped tube portion of the heat transfer tube 33, 33c is a tube wall of the heat transfer tube 33, and 35 is A bowl-shaped water guide member, 36 is a rib piece for water guide, 37 is a protruding member for water guide, and 38 is a slit for water guide.

Claims (7)

  A copper heat transfer tube composed of a straight tube portion and a U-shaped tube portion connecting the end portions of the straight tube portion, and a plurality of heat transfer tubes arranged in parallel at a predetermined pitch with respect to the straight tube portion of the heat transfer tube. A cross fin coil type heat exchanger comprising a heat fin and a pair of metal tube plates fitted on the straight tube portion of the heat transfer tube located on both sides of the plurality of heat transfer fins. The water guide for blocking the flow of water between the upper and lower outer tube portions of the plurality of heat transfer tubes and guiding them to the front end side or the rear end side of the tube plates on the outer surfaces of the pair of tube plates The heat exchanger characterized by the above-mentioned.   The heat exchanger according to claim 1, wherein the water guide is a bowl-shaped member provided on the outer surface of the tube sheet.   The heat exchanger according to claim 2, wherein the flange member is formed by cutting and raising a part of the tube sheet.   The heat exchanger according to claim 2, wherein the flange-shaped member is formed by subjecting a part of the tube sheet to rib processing.   The heat exchanger according to claim 2, wherein the bowl-shaped member is formed by attaching a member different from the tube sheet.   The heat exchanger according to claim 1, wherein the water guide is a slit formed in a part of the tube sheet.   The heat exchanger according to claim 1, wherein the water guide is a concave groove formed in a part of the tube sheet.

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