JP2010175103A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger properly draining a heat absorption pipe with a simple structure even when the heat absorption pipe is thinned. <P>SOLUTION: In this heat exchanger 5 in which the heat absorption pipe 52 is disposed in a case 50 where a combustion exhaust flows, one end section and the other end section of the heat absorption pipe 52 are connected with an inflow header 6a and an outflow header 6b disposed on a side plate 51 of the case 50, and the water flowing into the heat absorption pipe 52 is heated by the combustion exhaust, the inflow header 6a the height position of which is on a low position side, is provided with a drainage plate 7 opposed to pipe end openings 52a to form a drainage flow channel for the water reaching the pipe end openings 52a in draining the heat absorption pipe 52, the drainage flow channel is formed by a recessed groove 70 formed on an opposite face to the pipe end openings 52a, of the drainage plate 7 and extending in the vertical direction, and the recessed groove 70 has a groove width narrower than a diameter of the pipe end openings 52a, and is disposed in opposition to the pipe end openings 52a, and continuously opposed to the plurality of pipe end openings 52a arranged in the vertical direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heat exchanger that heats and heats water flowing into a heat absorption pipe via an inflow header and an outflow header by combustion exhaust.

  A latent heat heat exchanger mounted on a high-efficiency hot water supply apparatus has a plurality of heat absorption tubes arranged in a case through which combustion exhaust flows, and one end portion and the other end portion of these heat absorption tubes are connected to an inflow header and an outflow header of a case side plate. And is configured to collect the latent heat by allowing water to flow through the heat absorption tube to condense the water vapor in the combustion exhaust (Patent Document 1).

  In such a latent heat exchanger, the heat absorption tube is made narrower in order to realize further downsizing and higher efficiency. That is, by reducing the size of the heat absorption tube, more heat absorption tubes can be arranged in the limited space of the case, and the heat transfer area of the entire heat absorption tube can be increased. However, if the endothermic tube is made thinner, when water is drained from the endothermic tube to prevent freezing in the endothermic tube in winter, a water film is stretched at the end of the endothermic tube due to the surface tension of the water. Water sometimes remained in the downstream portion of the heat absorption pipe in the flowing direction. Therefore, when the heat absorption tube is made thin, it is also desired that the water draining operation in the heat absorption tube is smoothly performed.

  By the way, as shown in FIG. 8, as a conventional latent heat exchanger 805, an extended tube portion 851 is connected to the end of the heat absorption tube 850, and this extended tube portion 851 is exposed to the outside of the case 870. Then, there is a type in which a header 806A is attached to the tip, and a bent portion 851a whose height decreases toward the tip (Patent Document 2). According to this, even when the endothermic tube 850 is narrowed, the water head pressure of the water existing in the bent portion 851a of the extended tube portion 851 acts on the tip of the extended tube portion 851, and during draining work. It is supposed that a water film is prevented from being stretched at the distal end opening of the extended tube portion 851 and smooth drainage is possible.

  However, the conventional latent heat exchanger 805 shown in FIG. 8 prevents the downsizing of the heat exchanger 805 by newly providing the extended tube body portion 851, and also prevents each of the plurality of heat absorption tubes 850. Therefore, there is a problem that the number of parts is increased and the number of connecting portions such as brazing is increased.

JP2007-163096

JP2007-333343

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a heat exchanger in which drainage of an endothermic tube is appropriately performed with a simple structure even when the endothermic tube is narrowed. To do.

The heat exchanger according to the present invention is
An endothermic tube is arranged in the case through which the combustion exhaust flows, and one end and the other end of the endothermic tube are connected to an inflow header and an outflow header provided on the side plate of the case, and the water flowing in the endothermic tube is heated by the combustion exhaust. In heat exchangers that exchange heat,
On the header whose height position is located on the low position side, a drainage plate is arranged in parallel in the vertical direction to form a drainage channel that reaches the pipe end opening when draining the heat absorption pipe. A plurality of pipe end openings are continuously arranged to face each other.

  As a result, even if a water film due to the surface tension of water is held in the pipe end opening when draining the heat absorption pipe, the water reaching the pipe end opening is drained by the drain plate. To flow out from the pipe end opening to the drainage channel. Formation of a water film due to the surface tension of water at the pipe end opening is prevented by the outflow of water from the pipe end opening to the drain passage. Therefore, even when the diameter is reduced by reducing the endothermic tube, the water in the endothermic tube does not remain in the downstream portion of the endothermic tube in the flowing direction due to the surface tension of the water at the pipe end opening of the endothermic tube. Unplugging is performed reliably. Moreover, since the drainage plate is provided in the header, it does not hinder downsizing of the heat exchanger.

The drainage channel is constituted by a concave groove formed in the drainage plate extending in the vertical direction,
The concave groove preferably has a groove width narrower than the diameter of the pipe end opening and communicates with the pipe end opening.
As a result, even when a water film due to the surface tension of the water is formed at the pipe end opening when draining the heat absorption pipe, the water reaching the pipe end opening is guided to the concave groove serving as the water drainage channel. , Will flow down the groove. Formation of a water film due to the surface tension of water at the pipe end opening is prevented by water flowing from the pipe end opening to the concave groove. Therefore, even when the diameter is reduced by reducing the endothermic tube, the water in the endothermic tube does not remain in the downstream portion of the endothermic tube in the flowing direction due to the surface tension of the water at the pipe end opening of the endothermic tube. Unplugging is performed reliably.

The drainage channel is constituted by a gap between the pipe end opening and the drainage plate,
The gap is desirably set to be equal to or less than the rising amount of the water film formed in the pipe end opening due to the surface tension of water.
As a result, even when a water film due to the surface tension of water is formed at the pipe end opening when draining the heat absorption pipe, the water reaching the pipe end opening is guided to the gap serving as the water drainage channel. After that, it flows down the drainage plate. Formation of a water film due to the surface tension of the water at the pipe end opening is prevented by the water flowing down from the pipe end opening through the drain plate. Therefore, even when the diameter is reduced by reducing the endothermic tube, the water in the endothermic tube does not remain in the downstream portion of the endothermic tube in the flowing direction due to the surface tension of the water at the pipe end opening of the endothermic tube. Unplugging is performed reliably.

The drain plate is constituted by a water permeable member.
Thereby, since water can pass smoothly through the drain plate, it can be smoothly performed without disturbing the flow of water to the heat absorption pipe via the header during normal use of the heat exchanger.

  As described above, according to the heat exchanger of the present invention, even when the endothermic tube is made thin, it is possible to reliably drain the endothermic tube with a simple configuration in which a drainage plate is arranged at the pipe end opening. It can be carried out. Therefore, there is no problem such as remaining water in the endothermic tube even though the drainage operation is performed, and freezing in the winter and damaging the endothermic tube. Therefore, it is possible to provide a heat exchanger that can achieve miniaturization and high efficiency and can appropriately drain water from the heat absorption pipe.

It is sectional drawing which shows the structure of the hot water supply apparatus provided with the heat exchanger in embodiment. It is the perspective view which decomposed | disassembled the part of the inflow header of a subheat exchanger. It is a cross-sectional view which shows the internal structure of the inflow header in a subheat exchanger. It is a longitudinal cross-sectional view which shows the internal structure of the inflow header in a subheat exchanger. It is a figure which shows the drain plate. It is a cross-sectional view which shows the internal structure of the inflow header of the subheat exchanger by other embodiment. It is a longitudinal cross-sectional view which shows the internal structure of the inflow header of the subheat exchanger by other embodiment. It is a side view which shows the latent-heat heat exchanger provided with the water draining structure in an endothermic tube as a prior art example.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
A hot water supply apparatus 1 shown in FIG. 1 is a latent heat recovery type hot water supply apparatus 1, and includes a combustion housing 3 containing a gas burner 31 in an outer case 2, a main heat exchanger 4 above the combustion housing 3, and main heat exchange. The auxiliary heat exchanger 5 above the unit 4 is provided. An air supply fan 11 that supplies combustion air into the combustion housing 3 is installed below the combustion housing 3.

  The main heat exchanger 4 includes a large number of endothermic fins 41 arranged in parallel in the body 40 through which the combustion exhaust gas of the gas burner 31 flows, and an endothermic pipe 42 penetrating the endothermic fins 41 in a meandering shape. ing. The auxiliary heat exchanger 5 is a latent heat exchanger, and includes a plurality of heat absorption tubes 52 arranged in a meandering manner in the case 50. The endothermic tube 52 is formed by bending a corrugated tube made of a corrosion-resistant metal such as stainless steel or titanium into a meandering shape. The side plate 51 on one side of the case 50 is provided with an inflow header 6a and an outflow header 6b. One end of a plurality of heat absorption tubes 52 is connected to the inflow header 6a, and the other end is connected to the outflow header 6b. It is connected. A water supply pipe 81 is connected to the inflow header 6a, and a connection pipe 83 connected to the upstream end of the heat absorption pipe 52 of the main heat exchanger 4 is connected to the outflow header 6b. A tapping pipe 82 is connected to the downstream end of the heat absorption pipe 52 of the main heat exchanger 4. The auxiliary heat exchanger 5 has an exhaust inlet 54 for combustion exhaust that has passed through the main heat exchanger 4 at the rear of the bottom plate 53, and exhausts the combustion exhaust that has passed through the auxiliary heat exchanger 5 on the front surface of the case 50. An exhaust port 55 is provided.

  When a hot water tap (not shown) at the downstream end of the hot water pipe 82 is opened, water is passed from the water supply pipe 81 to the heat absorption pipe 52 of the sub heat exchanger 5 and the heat absorption pipe 42 of the main heat exchanger 4. The gas burner 31 is burned. In the main heat exchanger 4, sensible heat is mainly absorbed from the combustion exhaust gas generated by the combustion of the gas burner 31, and the water flowing in the heat absorption pipe 42 is heat exchange heated. The auxiliary heat exchanger 5 condenses the water vapor in the combustion exhaust and absorbs latent heat to heat and heat the water in the heat absorption pipe 52. As a result, the hot water heated by the sub heat exchanger 5 and the main heat exchanger 4 is discharged from the hot water discharge pipe 82.

  The auxiliary heat exchanger 5 is installed with a slight inclination (about 5 °) in the rearward direction. Acidic drain water generated by the condensation of water vapor in the combustion exhaust gas in the auxiliary heat exchanger 5 is dropped on the inclined bottom plate 53, and passes through the drain drain pipe 57 from the drain recovery portion 56 at the lower position and is neutralized in the neutralizer 58. After being summed, it is drained into the sewer.

  As shown in FIGS. 2, 3, and 4, the inflow header 6 a and the outflow header 6 b in the sub heat exchanger 5 are formed from a recess recessed inward of the case 50 by drawing a predetermined position of the side plate 51. And a header lid 62 which is disposed from the outside of the case 50 and defines a closed space 60 between the header body 61 and the header body 61. The header body 61 has a plurality of insertion openings 63 for the heat absorption pipes 52 corresponding to the plurality of heat absorption pipes 52, and the header lid 62 has a single joint portion for the water supply pipe 81 and the connection pipe 83. 64 is provided. The header lid 62 is formed in a shallow vessel shape in which the back side where the joint portion 64 is not provided forms a peripheral wall 65 on the entire periphery. The header lid 62 is fitted in the recess of the header body 61 with the back side of the header lid 62 facing the recess of the header body 61, and brazing is performed with the inner wall of the recess of the header body 61 and the outer surface of the peripheral wall 65 of the header lid 62 overlapped. Thus, the headers 6a and 6b are formed.

  As for the inflow header 6a and the outflow header 6b, the position of the joint part 64 is such that the inflow header 6a is provided on the lower side and the outflow header 6b is provided on the upper side (see FIG. 2). Since the auxiliary heat exchanger 5 is installed at an angle, the height of the inflow header 6a is arranged at a lower position.

  As described in the background art, the heat absorption pipe 52 of the auxiliary heat exchanger 5 can be made narrower in response to a request for further miniaturization and higher thermal efficiency of the heat exchanger. In the auxiliary heat exchanger 5 in the present embodiment, the diameter of the heat absorption tube 52 is φ10 mm, and eight heat absorption tubes 52 are disposed. Thereby, many heat absorption pipes 52 are arranged in a limited space, the size is reduced, and the heat transfer area of the heat absorption pipes 52 is increased to achieve high thermal efficiency. However, if the endothermic tube 52 is narrowed, a water film is formed in the pipe end opening 52a due to the surface tension of water when water is drained from the endothermic tube 52, and water may remain in the downstream portion of the endothermic tube 52 in the flowing direction. is there. Therefore, in the present embodiment, in order to smoothly drain water even if the heat absorption tube 52 is narrowed, it is configured as follows.

  In the inflow header 6a disposed on the low position side, a drain plate 7 formed of punching metal is disposed on the bottom 66 in the header body 61 so as to face the pipe end opening 52a. Many punch holes 75 of the drain plate 7 have a smaller diameter than the pipe end opening 52a. The drain plate 7 forms a drain channel for the water that has reached the pipe end opening 52 a when draining the heat absorption pipe 52. In the drain plate 7, two concave grooves 70 extending in the vertical direction are formed on the opposite surface side of the pipe end opening 52 a, and these concave grooves 70 serve as the drain channel. Each concave groove 70 is continuously opposed to the pipe end opening 52a of each heat absorption pipe 52 arranged in parallel in the vertical direction by four at the left and right positions. The groove widths of these concave grooves 70 are narrower than the diameter of the pipe end opening 52a. For example, the diameter of the pipe end opening 52a is 10 mm, and the groove width of the groove 70 is set to about 1 mm.

  Referring to FIG. 5, the drain plate 7 has rib peaks 71 for forming the concave grooves 70, and bent portions 73 bent toward the rib peaks 71 at both ends. Yes. The drainage plate 7 is set to a size such that the upper end surface of the peripheral wall 65 of the header lid 62 is brought into contact with the tip of the bent portion 73 and the top portion 72 of the rib crest 71 is brought into contact with the bottom surface 67 of the header lid 62. ing. The drainage plate 7 has a size such that the outer shape is substantially along the bottom 66 of the header body 61. Therefore, the rib crest 71 contributes to securing the strength of the drain plate 7 and when the header lid 62 is fitted into the header body 61, the rib crest 71 is brought into contact with the bottom surface 67 of the header lid 62 so that the drain plate 7 is connected to the pipe. It is held in contact with the end opening 52a. The bent portions 73 on both sides of the drain plate 7 are also brought into contact with the upper end surface of the peripheral wall 65 of the header lid 62 to hold the drain plate 7. In this way, the drain plate 7 is disposed so as to contact the pipe end opening 52a, so that the opening of the groove 70 is in contact with the pipe end opening 52a.

  Then, when draining work, when a drain plug (not shown) in the water supply pipe 81 and the hot water discharge pipe 82 is opened, initially, the heat absorption pipe 52 has a difference in height between one end and the other end. Water flows out smoothly from the pipe end opening 52a. At this time, since the drain plate 7 is made of punching metal, the water in the heat absorption pipe 52 is drained from the pipe end opening 52a through the numerous punch holes 75 of the drain plate 7. And if the water in the endothermic pipe 52 passes to the downstream part in the flowing direction of the endothermic pipe 52, the water head pressure due to the difference in height of the endothermic pipe 52 becomes smaller. A water film may be formed in the pipe end opening 52a due to the surface tension, and water may remain in the downstream portion of the heat absorption pipe 52 in the flowing direction. In the present embodiment, when water is drained to the downstream portion in the flowing direction of the heat absorption pipe 52, the water that has reached the pipe end opening 52 a enters the concave groove 70 of the drain plate 7 and flows down along the concave groove 70. Go. Therefore, the water in the downstream portion of the heat absorption pipe 52 in the flowing direction is drained through the concave groove 70.

The principle of this drainage is considered as follows.
The water that has reached the pipe end opening 52 a is permeated into the concave groove 70 based on the capillary phenomenon in the concave groove 70, and the water that has permeated the concave groove 70 has its own weight and the capillary phenomenon in the concave groove 70. In combination, it is considered that it flows down along the concave groove 70. In this way, the water that has reached the pipe end opening 52a is sequentially flowed through the concave groove 70, so that even if the water head pressure due to the height difference of the heat absorption pipe 52 is reduced, the pipe end opening 52a has no water. A water film due to the surface tension of the heat absorption pipe 52 is not formed, and water in the downstream portion of the heat absorption pipe 52 in the flowing direction is not drained through the concave groove 70.

  Therefore, even when the diameter is reduced by reducing the endothermic tube 52, water does not remain in the downstream portion of the endothermic tube 52 in the flowing direction due to the surface tension of the water at the pipe end opening 52a of the endothermic tube 52. The drainage of the heat absorption pipe 52 is reliably performed. As described above, according to the auxiliary heat exchanger 5 in the present embodiment, even when the heat absorption tube 52 is narrowed, the heat absorption tube 52 can be configured with a simple configuration in which the drainage plate 7 is disposed in the pipe end opening 52a. Water can be drained reliably. Therefore, there is no problem such as remaining water in the endothermic tube 52 in spite of the draining operation, freezing in the winter and damaging the endothermic tube 52. Therefore, it is possible to provide the latent heat exchanger 5 that can achieve downsizing and high efficiency and can appropriately drain the heat absorption pipe 52.

  Since the water drain plate 7 is made of punching metal, water can smoothly pass through the water drain plate 7 and to the heat absorption pipe 52 via the inflow header 6a when the latent heat exchanger 5 is normally used. Can be carried out smoothly without obstructing the flow of water. In addition, although the draining plate 7 is comprised with a punching metal, it can comprise not only this but various water permeable members, such as an expanded metal, a net | network, a mesh, and a filter. Moreover, although the metal plate is used suitably for the water draining plate 7, materials, such as a plastic and a ceramic, may be used.

(Other embodiments)
As shown in FIGS. 6 and 7, in another embodiment, a drain plate 7x formed of a punching metal is disposed so as to provide a pipe end opening 52a and a gap 70a. The gap 70a between the drain plate 7x and the pipe end opening 52a is set to be less than the rising amount of the water film formed in the pipe end opening 52a due to the surface tension of water. A drainage flow path is formed at the time of draining in 52. For example, the diameter of the pipe end opening 52a is 10 mm, and the gap 70a is set to about 1 mm.

  The drain plate 7x is set to a size such that one rib crest 71 extending in the vertical direction is formed at the center in the width direction, and the top 72 of the rib crest 71 is in contact with the bottom surface 67 of the header lid 62. Has been. At both ends of the drainage plate 7x, a bent portion 73 is formed which is brought into contact with the upper end surface of the peripheral wall 65 of the header lid 62 and bent toward the rib crest 71. Therefore, the rib crest 71 contributes to securing the strength of the drain plate 7 and when the header lid 62 is fitted into the header body 61, the rib crest 71 is brought into contact with the bottom surface 67 of the header lid 62 and the drain plate 7x is connected to the pipe. The end opening 52a is held with a gap 70a. The bent portions 73 on both sides of the drain plate 7x are also brought into contact with the upper end surface of the peripheral wall 65 of the header lid 62 to hold the drain plate 7x.

  When water is drained to the downstream portion of the heat absorption pipe 52 in the direction of water flow, the water that has reached the pipe end opening 52a is guided to the gap 70a between the pipe end opening 52a and the water drain plate 7x. It flows down along the punch plate 7x. Therefore, the water in the downstream portion of the heat absorption pipe 52 in the flowing direction is drained through the drain plate 7x.

  That is, when the water reaching the pipe end opening 52a rises outward at the pipe end opening 52a and comes into contact with the water drain plate 7x, the pipe end opening is caused by the capillary phenomenon of the gap 70a between the pipe end opening 52a and the water drain plate 7. It is considered that the water guided to the gap 70a between the water drain plate 7x and the water drain plate 7x flows down along the water drain plate 7x in combination with its own weight and the capillary phenomenon of the gap 70a. . Thus, the water that has reached the pipe end opening 52a is sequentially flowed through the drain plate 7x, so that even if the water head pressure due to the height difference of the heat absorption pipe 52 is reduced, the pipe end opening 52a has A water film due to the surface tension of the water is not formed, and the water in the downstream portion of the heat absorption pipe 52 in the flowing direction is not drained through the drain plate 7x. Therefore, even when the diameter is reduced by reducing the endothermic tube 52, water does not remain in the downstream portion of the endothermic tube 52 in the flowing direction due to the surface tension of the water at the pipe end opening 52a of the endothermic tube 52. The drainage of the heat absorption pipe 52 is reliably performed. Other configurations and operational effects of the other embodiments shown in FIGS. 6 and 7 are the same as those of the embodiment shown in FIGS. 3 and 4.

In addition, this invention is not limited only to the said embodiment, A various change is possible within the scope of the present invention.
For example, the endothermic tube 52 may be arranged in a spiral shape, a spiral shape, or the like instead of a horizontal meandering shape.
The heat exchanger is not limited to the hot water supply device, and may be used for various heat exchange devices.

DESCRIPTION OF SYMBOLS 1 Hot water supply apparatus 2 Exterior case 3 Combustion housing 4 Main heat exchanger 5 Sub heat exchanger 6a Inflow header 6b Outflow header 7, 7x Drain plate 42 Heat absorption pipe 50 Case 51 Side plate 52 Heat absorption pipe 52a Pipe end opening 61 Header main body 60 Closure Space 62 Header lid 63 Insertion port 64 Joint portion 65 Header cover peripheral wall 66 Header body bottom 67 Header lid bottom surface 70 Groove 70a Clearance 71 Rib crest 72 Rib crest top 73 Bending part

Claims (4)

An endothermic tube is arranged in the case through which the combustion exhaust flows, and one end and the other end of the endothermic tube are connected to an inflow header and an outflow header provided on the side plate of the case, and the water flowing in the endothermic tube is heated by the combustion exhaust. In heat exchangers that exchange heat,
On the header whose height position is located on the low position side, a drainage plate is arranged in parallel in the vertical direction to form a drainage channel that reaches the pipe end opening when draining the heat absorption pipe. A heat exchanger arranged continuously opposite to a plurality of pipe end openings. The heat exchanger according to claim 1,
The drainage channel is constituted by a concave groove formed in the drainage plate extending in the vertical direction,
The concave groove is a heat exchanger in which the groove width is narrower than the diameter of the pipe end opening and communicates with the pipe end opening. The heat exchanger according to claim 1,
The drainage channel is constituted by a gap between the pipe end opening and the drainage plate,
The said clearance gap is a heat exchanger set below the amount of swelling of the water film formed in the pipe end opening resulting from the surface tension of water. The heat exchanger according to any one of claims 1 to 3,
The water drain plate is a heat exchanger composed of a water permeable member.

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