JP2005321138A - Heat exchanger for water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger for a water heater, having improved performance of draining condensed water produced from combustion gas supplied downward to fins. <P>SOLUTION: The heat exchanger for the water heater comprises a plurality of layered tubes 110 having fluid passages formed therein and the fins 120 laid between the plurality of tubes 110 for increasing a heat transfer area. Combustion gas flows downward from the regions of the fins 120 and supply hot water is distributed in the fluid passages of the tubes 110 so that sensible heat as well as condensed latent heat are collected from the combustion gas to heat the supply hot water. On the flat faces 121 of the fins 120 joined to each other between the plurality of adjacent tubes 110, uneven portions 122 for improving heat exchanging efficiency and non-formed portions 123 where no uneven portions 122 are formed are alternately provided in the direction of distributing the combustion gas. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat exchanger for a hot water heater that exchanges heat between hot water flowing through a tube and combustion gas flowing through a fin region interposed between the tubes.

  As a conventional heat exchanger, for example, the one shown in Patent Document 1 is known. That is, this heat exchanger is an evaporator for an air conditioner, and is formed by interposing fins (corrugated fins) between a plurality of stacked tubes (refrigerant tube portions in Patent Document 1). Here, the conditioned air is circulated through the fin region in the horizontal direction, the fin is divided into a plurality of conditioned air distribution directions, and each divided fin is disposed with a gap. Yes.

As a result, the condensed water generated when the conditioned air is cooled can flow down along the wall surface of the tube from the gaps of the fins. I try to improve.
Japanese Patent Laid-Open No. 10-141805

  However, in the case where the heat exchanger is used in a posture in which the direction of the external fluid (combustion gas) flowing through the fin region is from the upper side to the lower side, like the heat exchanger for a hot water heater, the condensation generated from the combustion gas Since water flows down in the fins due to gravity, the gaps between the fins in the prior art do not make sense, and stagnation occurs due to the condensation of the condensed water in the fins, leading to a reduction in heat exchange efficiency.

  In view of the above problems, an object of the present invention is to provide a heat exchanger for a hot water heater that is excellent in drainage of condensed water generated from combustion gas supplied downward from above to the fin.

  In order to achieve the above object, the present invention employs the following technical means.

  According to the first aspect of the present invention, the fluid passage is formed in the interior, the plurality of tubes (110) arranged in a stack, and the fins interposed between the plurality of tubes (110) to increase the heat transfer area. (120), and the combustion gas flows through the fin (120) from the top to the bottom, and hot water is circulated in the fluid passage of the tube (110) to condense not only sensible heat but also the combustion gas. A heat exchanger for a hot water heater that also collects latent heat and heats hot water supply, and the flat portion (121) of the fin (120) connected between a plurality of adjacent tubes (110) has a heat exchange efficiency. The uneven portions (122) for improving and the non-formed portions (123) where the uneven portions (122) are not formed are alternately provided in the combustion gas flow direction.

  In the water heater heat exchanger (100), condensed water is generated from the combustion gas during heat exchange, and this condensed water is first generated as fine droplets on the surface of the fin (120). And these fine droplets are actively collected by the non-formation part (123). That is, in the non-formation part (123) maintained flat, fine droplets that are close to each other are united by surface tension. Further, the droplets of the uneven portion (122) adjacent to the non-formed portion (123) are also absorbed here by the surface tension, and the droplet grows in a short time.

  Then, when the downward force due to the weight of the droplet grown in the non-forming part (123) and the wind pressure of the combustion gas exceeds the surface tension of the liquid droplet in the non-forming part (123), the liquid droplet is immediately lowered. Will fall (leave).

  In this way, by repeating the cycle of actively collecting the generated droplets in the non-forming part (123) and sequentially separating the coalesced and grown droplets, the droplets are uneven on the fin (120). It is possible to prevent adhesion stagnation at the portion (122). Therefore, it can be set as the heat exchanger (100) for hot water heaters which is excellent in drainage of condensed water.

  The invention according to claim 2 is characterized in that the non-forming part (123) is formed larger on the outflow side than on the inflow side of the combustion gas.

  The condensed water is generated by the temperature decrease of the combustion gas during heat exchange (below the dew point temperature) and is generated more on the outflow side than the inflow side of the combustion gas. By forming (123) largely on the outflow side, the drainage of the condensed water described in claim 1 can be effectively exhibited.

  Moreover, since more uneven | corrugated | grooved parts (122) can be formed in an upstream, the heat transfer effect | action of a fin (120) can be improved and the heat exchange efficiency of combustion gas and hot water supply can be improved.

  Then, as in the invention described in claim 3, the concavo-convex portion (122) is used as the louver portion (122), and the non-formed portion (123) is a turning portion that turns the direction of the louver portion (122) ( 123) can be easily formed.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows a corresponding relationship with the specific means of embodiment description mentioned later.

(First embodiment)
1st Embodiment of this invention is described based on drawing shown in FIGS. 1 is a side view showing a heat exchanger 100 for a water heater, FIG. 2 is an arrow view (plan view) seen from the direction A of FIG. 1, and FIG. 3 is an arrow view seen from the direction B of FIG. 4 is a cross-sectional view showing the CC section of FIG. 3, FIG. 5 is a cross-sectional view showing the DD section of FIG. 4, and FIG. 6 is a model of the condensed water on the combustion gas outflow side of FIG. FIG.

  A water heater heat exchanger (hereinafter referred to as a heat exchanger) 100 according to the present invention is used in a water heater (not shown) and is disposed in a case member. In this heat exchanger 100, heat exchange is performed between the combustion gas that flows through the core portion 100a of the heat exchanger 100 and the hot water that flows through the heat exchanger 100 (tube 110). It is supposed to be heated.

  Incidentally, the water heater is provided with a primary heat exchanger, and the present heat exchanger 100 is disposed on the upper side of the primary heat exchanger and functions as a secondary heat exchanger. That is, the combustion gas generated by the gas burner and having passed through the primary heat exchanger is introduced into the case member and supplied to the heat exchanger 100, and hot water is supplied to the heat exchanger 100. After being distributed, it is supplied to the primary heat exchanger. Therefore, the hot water is heated in advance in the heat exchanger 100 and further heated in the primary heat exchanger, and used as hot water. In addition, the combustion gas which distribute | circulated the heat exchanger 100 is discharged | emitted outside from the gas discharge port provided in the main-body part of the water heater from the case member.

  As shown in FIGS. 1 to 4, the heat exchanger 100 is a so-called drone cup type heat exchanger configured by stacking a plurality of tubes 110 together with outer fins (hereinafter, fins) 120. Each member (described below) constituting the heat exchanger 100 is made of a stainless steel material, and after the members are assembled into the shape of the heat exchanger 100, they are integrally brazed and joined. Yes.

  The tube 110 includes a pair of tube plates 111 and 112, and is in contact with and joined to each other by flange portions 111a and 112a provided on the outer peripheral portions of the tube plates 111 and 112. Both end sides in the longitudinal direction of both tube plates 111 and 112 are drawn deeper than the intermediate region. As the tube 110, a flat tube portion 110a is provided in the intermediate region, and a first tank portion 110b and a second tank are provided on both end sides, respectively. A portion 110c is formed.

  In addition, in the inside of the flat tube portion 110a of the tube 110 (corresponding to the fluid passage in the present invention), an inner fin 160 having an uneven cross section that increases the heat transfer area and gives a turbulent flow effect to the hot water flowing inside the tube 110 ( 4) has been inserted. Incidentally, the inner fin is a so-called offset type fin formed so that the concavo-convex cross-sections are offset and arranged.

  The plurality of tubes 110 are stacked so that the first tank portions 110b communicate with each other and the second tank portions 110c communicate with each other. Accordingly, the plurality of flat tube portions 110a communicate with each other via the first tank portions 110b and the second tank portions 110c.

  The fins 120 are corrugated fins that have a corrugated shape as viewed from the flow direction of the combustion gas, and are interposed between the flat tube portions 110 a of the tubes 110. The flat tube portion 110a and the fins 120 form a core portion (heat exchange portion) 100a. In the present invention, the shape of the fin 120 is characterized, and details will be described later.

  A hot water supply port 130 and a hot water outlet 140 are provided at one end in the stacking direction of the tubes 110, and the hot water supply port 130 is connected to communicate with the first tank unit 110b. The two tank portions 110c are connected to communicate with each other. Reinforcing plates 150 are provided in regions corresponding to the first tank portion 110b and the second tank portion 110c of the tube 110 disposed at both ends in the stacking direction.

  The heat exchanger 100 formed in this way is used in a posture in which the stacking direction and the longitudinal direction of the tubes 110 are substantially horizontal so that the combustion gas is supplied from the upper side to the lower side of the fin 120 region. (FIGS. 1 and 3).

  In the present invention, the flat portion 121 of the fin 120 connected between the adjacent tubes 110 is provided with the uneven portion 122 and the non-formed portion 123 (123a to 123c) where the uneven portion 122 is not formed. Are arranged alternately in the flow direction of the combustion gas.

  As shown in FIG. 5, the concavo-convex portion 122 increases the heat transfer area of the fin 120 and suppresses the formation of a boundary layer on the surface of the fin 120 when the combustion gas flows so that the local heat transfer coefficient (heat The louver part 122 has an armored door shape that improves the exchange efficiency.

  Moreover, the non-formation part 123 (123a-123c) is used as the turning part 123 (123a-123c) which turns the inclination direction of the said louver part 122, and in addition, it is the outflow side rather than the turning part 123a of the inflow side of combustion gas. The turning portion 123c has a larger area that is maintained in a planar shape without the louver portion 122 being formed.

  Here, four louver parts 122 having different inclination directions are provided, and turning parts 123a, 123b, and 123c are interposed between the four louver parts 122, and the combustion gas flow passage is long. It is a thing.

  Next, the operation of the heat exchanger 100 based on the above configuration and the operation and effect thereof will be described.

  Hot water is supplied from the hot water supply port 130 of the heat exchanger 100 to the first tank part 110b, flows through the flat tube part 110a of each tube 110, and flows out from the second tank part 110c through the hot water outlet 140.

  On the other hand, the combustion gas (combustion gas at 200 ° C. after passing through the primary heat exchanger) is introduced into a case member (not shown) and passes through the core portion 100a of the heat exchanger 100 from the top to the bottom. It is discharged outside from the gas outlet.

  The combustion gas exchanges heat with hot water when passing through the core portion 100a to heat the hot water. At this time, the combustion gas is condensed at a temperature lower than the dew point temperature (for example, 30 to 50 ° C.) at least on the outlet side (outflow side) of the core portion 100a. That is, the heat exchanger 100 can heat not only the sensible heat of the combustion gas but also the latent heat released when the combustion gas condenses to heat the hot water.

  Here, the condensed water is generated mainly on the outflow side of the combustion gas as described above, and this condensed water is first generated as fine droplets on the surface of the fin 120. And these fine droplets are actively collected by the turning part 123c which becomes the outflow side of combustion gas mainly.

  That is, as shown in FIG. 6, in the turning portion 123c having a large area that is maintained in a planar shape, fine droplets that are close to each other in the turning portion 123c are combined by surface tension. Furthermore, the droplets in the louver portion 122 adjacent to the turning portion 123c are also absorbed here by the surface tension, and the droplets grow in a short time.

  Then, when the downward force due to the weight of the droplet grown at the turning portion 123c and the wind pressure of the combustion gas exceeds the surface tension of the droplet at the turning portion 123c, the droplet falls (separates) all at once. To go.

  As described above, according to the present invention, the generated droplets are positively gathered in the turning portion 123c, and the cycle of merging and sequentially separating the grown droplets is repeated, so that the droplets are the louvers of the fins 120. It is possible to prevent adhesion stagnation in the portion 122. Therefore, it can be set as the heat exchanger 100 which is excellent in the drainage of condensed water.

  Further, on the inflow side of the combustion gas, there is little influence of condensed water generation, and by making the turning portions 123a and 123b smaller, more original louver portions 122 can be formed, and the heat transfer action of the fins 120 can be increased. The heat exchange efficiency between the combustion gas and the hot water supply can be improved.

(Other embodiments)
In contrast to the first embodiment, the concavo-convex portion is not limited to the louver portion 122, and may be a slit portion (slit fin) that is cut and raised in parallel to the flat portion 121. The non-formation part at this time should just be a part which left the plane part 121, without forming a slit part literally. Further, the fin 120 may be a plate type instead of the corrugated type.

It is a side view which shows the heat exchanger in 1st Embodiment. It is an arrow view (plan view) seen from the A direction of FIG. It is an arrow view (left side view) seen from the B direction of FIG. It is sectional drawing which shows the CC part of FIG. It is sectional drawing which shows the DD part of FIG. It is an enlarged view which shows the condensed water in the combustion gas outflow side of FIG.

Explanation of symbols

100 Heat exchanger for water heater 110 Tube 120 Outer fin (fin)
121 Plane part 122 Louver part (concave part)
123 Turning part (non-forming part)

Claims (3)

A plurality of tubes (110) that form a fluid passage therein and are arranged in layers;
A fin (120) interposed between the plurality of tubes (110) to increase a heat transfer area;
Combustion gas flows from the upper side to the lower side in the fin (120) region, and hot water is circulated in the fluid passage of the tube (110) to collect not only sensible heat but also latent heat of condensation from the combustion gas. And a heat exchanger for a hot water heater for heating the hot water.
The flat portion (121) of the fin (120) connected between the adjacent tubes (110) is provided with an uneven portion (122) for improving heat exchange efficiency, and an uneven portion (122). Non-formed parts (123) that are not formed are alternately provided in the flow direction of the combustion gas.   2. The heat exchanger for a hot water heater according to claim 1, wherein the non-forming part (123) is formed larger on the outflow side than on the inflow side of the combustion gas. The uneven portion (122) is a louver portion (122),
The water heater heat exchanger according to claim 1 or 2, wherein the non-forming part (123) is a turning part (123) that turns the direction of the louver part (122).

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