JP2005337576A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger 17 detachable from a hot water storage tank, having sufficient heat exchanging performance adequate for reheating hot water in a bathtub while doing away with a fin. <P>SOLUTION: The heat exchanger 17 comprises a flange 31 detachably mounted on a heat exchanger mounting port of the hot water storage tank and a heat exchange pipe 32 provided on the flange 31 in the state of being inserted through the heat exchanger mounting port into the hot water storage tank, the heat exchange pipe 32 being 4.5-6.5 m long. Thus, it has sufficient heat exchanging performance adequate for the reheating the hot water in the bathtub while doing away with the fin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat exchanger that exchanges heat with hot water stored in a hot water storage tank.

  Conventionally, in a hot water supply apparatus in which hot water is boiled and stored in a hot water storage tank of an electric water heater, and the hot water stored in the hot water storage tank is supplied, There is a hot water supply device with a memorial function that provides a heat exchanger that circulates the hot and cold water, and uses the heat of the hot water stored in the hot water storage tank to replenish hot water filled in the bathtub.

  If the heat exchanger is removable from the hot water storage tank, it can be inspected and replaced. In order to configure the heat exchanger to be detachable, a heat exchanger mounting port is formed on the side of the hot water storage tank, and the heat exchanger flange is attached to the heat exchanger mounting port in a liquid-tight manner by bolting. It is done. The heat exchange pipe is fixed to the flange in a liquid-tight manner in a penetrating state, and both ends of the heat exchange pipe protrude to the outside of the flange, and an intermediate portion protrudes to the inside of the flange from the heat exchanger mounting port. Inserted into the hot water storage tank.

In many cases, the heat exchange pipe is formed in a substantially U shape so that it can be inserted into the hot water storage tank from the heat exchanger attachment port. . Therefore, a plurality of fins are fixed around the heat exchange pipe, the heat transfer area is increased, the heat exchange performance is improved, and the chasing time is shortened (for example, refer to Patent Document 1).
Japanese Utility Model Publication No. 63-19143 (first page, FIG. 1-6)

  However, in the conventional heat exchanger, since it is necessary to fix a plurality of fins around the heat exchange pipe, it takes time and effort to manufacture, and the manufacturing cost increases. There is a gap between the two, and depending on the water quality, pitting corrosion tends to occur in the heat exchange pipe, and there is a problem that early replacement is necessary.

  The present invention has been made in view of the above points, and in a heat exchanger that can be attached to and detached from a hot water storage tank, the fins can be eliminated and sufficient heat exchange performance can be obtained. It is an object to obtain heat exchange performance suitable for the above.

  The heat exchanger according to claim 1 is a heat exchanger in which hot water is circulated between the bathtub and the hot water in the hot water storage tank, and is attached to and detached from a heat exchanger mounting port formed in the hot water storage tank. A flange that can be attached, and a length of 4.5 to 6.5 m, both ends projecting to the outside of the flange, and an intermediate part projecting to the inside of the flange, from the heat exchanger mounting port to the hot water storage tank And a heat exchange pipe inserted and disposed therein.

  And if the length of the heat exchange pipe is shorter than 4.5 m, sufficient heat exchange performance cannot be obtained, the remedy time is longer than necessary, and the length of the heat exchange pipe is 6.5 m. If it is longer, it may be difficult to insert the heat exchange pipe into the hot water storage tank from the heat exchanger attachment port, or the heat exchange performance may be too high, and the hot water temperature circulating in the bathtub may become too high. Therefore, in the heat exchanger detachable from the hot water storage tank, by making the length of the heat exchange pipe in the range of 4.5 to 6.5 m, sufficient heat exchange performance can be obtained after eliminating the fins, Heat exchange performance suitable for reheating bath water is obtained.

  The heat exchanger according to claim 2 is the heat exchanger according to claim 1, wherein the heat exchange pipe has an outer diameter of 11 to 15 mm.

  If the outer diameter of the heat exchange pipe is smaller than 11 mm, the heat transfer area with the hot water in the hot water storage tank is reduced and sufficient heat exchange performance cannot be obtained, and the outer diameter of the heat exchange pipe is 15 mm. If it is larger, it becomes difficult to insert the heat exchange pipe into the heat exchanger attachment port when the length of the heat exchange pipe is 4.5 to 6.5 m, or the heat exchange performance becomes so high that the hot water circulates in the bathtub. The temperature may become too high. Therefore, in the heat exchanger detachable from the hot water storage tank, in addition to setting the length of the heat exchange pipe in the range of 4.5 to 6.5 m, the outer diameter of the heat exchange pipe is set in the range of 11 to 15 mm. As a result, sufficient heat exchange performance can be obtained after eliminating the fins, and heat exchange performance suitable for reheating hot water in the bathtub can be obtained.

  The heat exchanger according to claim 3 is the heat exchanger according to claim 1 or 2, wherein both ends of the heat exchange pipe are projected to the outside of the flange, and the intermediate portion penetrates between the outside and inside of the flange. A plurality of substantially U-shaped heat exchange pipe portions protruding inside the flange by repeating a plurality of times are formed, and a plurality of folded pipe portions that are folded back outside the flange to connect the heat exchange pipe portions are formed. A plurality of heat exchange pipe portions are inserted and disposed in the hot water storage tank from the heat exchanger attachment port.

  Then, the heat exchange pipe projects both ends of the heat exchange pipe to the outside of the flange, and repeats the penetration of the intermediate portion of the heat exchange pipe between the outside and the inside of the flange a plurality of times to project to the inside of the flange. By forming a substantially U-shaped heat exchange pipe portion and forming a plurality of folded pipe portions that are folded back outside the flange to connect the heat exchange pipe portions, the plurality of heat exchange pipe portions are connected to the heat exchanger mounting port. Therefore, the required length of the heat exchange pipe can be ensured while being inserted into the hot water storage tank.

  The heat exchanger according to claim 4 is the heat exchanger according to claim 3, wherein a plurality of through holes through which the heat exchange pipe passes are formed in the flange, and the total area of the plurality of through holes is A, the heat of the flange. When the effective area of the region through which the exchange pipe can penetrate is B, the relationship is A / B> 0.16.

  And, if the ratio of the total area A of the plurality of through holes / the effective area B of the flange is smaller than 0.16 and the relationship of A / B <0.16, the necessary length of the heat exchange pipe is secured. In addition, with the relationship of A / B> 0.16, the heat exchange pipe portion that is inserted and disposed in the hot water storage tank through the flange within the limited size of the flange. The number can be increased and the necessary length of the heat exchange pipe can be secured.

  The heat exchanger according to claim 5 is the heat exchanger according to claim 3 or 4, wherein the heat exchange pipe includes a plurality of substantially U-shaped heat exchange pipe parts, wherein a predetermined number of heat exchange pipe parts are substantially U. The heat exchange pipe parts are arranged in a direction perpendicular to the letter-shaped surface and are arranged between the insides of a predetermined number of heat exchange pipe parts in which the remaining heat exchange pipe parts are arranged. The substantially U-shaped surfaces are arranged in an intersecting direction.

  The heat exchange pipe includes a plurality of substantially U-shaped heat exchange pipe portions, in which a predetermined number of heat exchange pipe portions are aligned in a direction perpendicular to the substantially U-shaped surface, and the remaining heat exchange pipe portions are arranged. A plurality of heat exchange pipe parts are arranged between the insides of the predetermined number of heat exchange pipe parts arranged in an arrangement so that the substantially U-shaped surfaces intersect the heat exchange pipe parts arranged in an aligned manner. Can be arranged closely to increase the number of heat exchange pipe portions, and the necessary length of the heat exchange pipe can be secured.

  The heat exchanger according to claim 6 is the heat exchanger according to any one of claims 1 to 5, wherein at least a part of a heat exchange pipe portion is bent toward an upper region in the hot water storage tank. It is.

  And the heat | fever of the upper part of a hot water storage tank can be utilized effectively by having bent the front-end | tip of at least one part heat exchange pipe part toward the upper area in a hot water storage tank.

  According to the heat exchanger according to claim 1, in the heat exchanger that can be attached to and detached from the hot water storage tank, the length of the heat exchange pipe is 4.5 to 6.5 m. In addition to obtaining heat exchange performance, it is possible to obtain heat exchange performance suitable for reheating hot water in a bathtub.

  According to the heat exchanger according to claim 2, in addition to the effect of the heat exchanger according to claim 1, sufficient heat exchange is achieved after eliminating the fins by setting the outer diameter of the exchange pipe to 11 to 15 mm. Performance can be obtained, and heat exchange performance suitable for reheating hot water in the bathtub can be obtained.

  According to the heat exchanger according to claim 3, in addition to the effect of the heat exchanger according to claim 1 or 2, the heat exchange pipe projects both ends of the heat exchange pipe to the outside of the flange, The intermediate portion is repeatedly penetrated between the outside and inside of the flange a plurality of times to form a plurality of substantially U-shaped heat exchange pipe portions projecting to the inside of the flange, and folded back on the outside of the flange between the heat exchange pipe portions. By forming the plurality of folded pipe portions to be connected, the plurality of heat exchange pipe portions can be inserted and disposed in the hot water storage tank from the heat exchanger attachment port, and the necessary length of the heat exchange pipe can be secured.

  According to the heat exchanger according to claim 4, in addition to the effect of the heat exchanger according to claim 3, the ratio of the total area A of the plurality of through holes to the effective area B of the flange is greater than 0.16. /B>0.16, the number of heat exchange pipes inserted through the flange and inserted into the hot water storage tank through the flange is limited within the limited size of the flange. The required length can be secured.

  According to the heat exchanger according to claim 5, in addition to the effect of the heat exchanger according to claim 3 or 4, the heat exchange pipe has a predetermined number of heats out of a plurality of substantially U-shaped heat exchange pipe portions. The exchange pipe portions are aligned in a direction perpendicular to the substantially U-shaped surface, and the remaining heat exchange pipe portions are aligned between a predetermined number of the heat exchange pipe portions that are aligned. By arranging in a direction where the substantially U-shaped surface intersects the pipe part, multiple heat exchange pipe parts can be densely arranged to increase the number of heat exchange pipe parts, ensuring the necessary length of the heat exchange pipe it can.

  According to the heat exchanger according to claim 6, in addition to the effect of the heat exchanger according to any one of claims 1 to 5, at least the tip of the heat exchange pipe portion is directed toward the upper area in the hot water storage tank. By bending, the heat at the top of the hot water tank can be used effectively.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 5 shows a simplified configuration diagram of a hot water supply device using a heat exchanger, 11 is an electric water heater of the hot water supply device, and this electric water heater 11 adopts a first-stop push-up hot water supply method, A hot water storage tank 12 is provided, a hot water supply pipe 13 is connected to the lower part of the hot water storage tank 12, and a hot water supply pipe 14 is connected to the upper part. A lower heater 15 and an upper heater 16 inserted and disposed in the hot water storage tank 12 are detachably and liquid-tightly attached to the lower and upper side surfaces of the hot water storage tank 12, respectively.

  A heat exchanger 17 inserted in the hot water storage tank 12 is detachably and liquid-tightly attached to the upper part of the side surface of the hot water storage tank 12, and hot water is added to the bathtub 18 between the heat exchanger 17 and the bath tub 18. A circulation pipe 19 for circulating the stretched hot water is connected, and a circulation pump 20 for circulating hot water in the bathtub 18 at a flow rate of, for example, 8.5 L / min is disposed in the circulation pipe 19. As shown in FIG. 2, an annular mounting seat 21 for mounting the heat exchanger 17 is provided on the side surface of the tank body 12 a of the hot water storage tank 12, and the heat exchanger 17 is inserted and disposed inside the mounting seat 21. A circular heat exchanger mounting port 22 is formed.

  1 to 3 show a heat exchanger 17, which is a flange 31 that is detachably attached to a mounting seat 21 of the hot water storage tank 12 and is liquid-tightly attached via a packing (not shown), and both ends are flanged. A heat exchanging pipe 32 is provided which protrudes outside 31 and has an intermediate portion protruding inside the flange 31 and inserted into the hot water storage tank 12 through the heat exchanger mounting port 22.

  As shown in FIG. 4, the flange 31 has a disk shape, and an annular mounting portion 34 formed with a plurality of mounting holes 33 bolted to the mounting seat 21 is formed in the peripheral portion. An effective surface portion 35 through which the heat exchange pipe 32 can penetrate is formed in a region facing the heat exchanger mounting port 22 inside, and a plurality of through holes 36 are formed in the effective surface portion 35. In the present embodiment, four through-holes 36 are arranged in two rows in the vertical direction, and two through-holes 36 are provided between the insides of these two rows of through-holes 36 and in the vertical position. In other words, there are three rows in the horizontal direction, two rows on both sides are arranged four in the vertical direction, and one middle row is arranged in the top and bottom.

  As shown in FIGS. 1 to 3, the heat exchange pipe 32 is, for example, a plurality of copper pipes connected in a liquid-tight manner to form one continuous pipe having a length of 4.5 to 6.5 m and an outer diameter. It is formed in a range of 11 to 15 mm and a pipe material thickness is 0.6 mm, and is liquid-tightly fixed to each through hole 36 of the flange 31 by brazing or the like.

  Both end portions of the heat exchange pipe 32 protrude outward through the through holes 36 of the flange 31, and connection pipe portions 38 and 39 having joints 37 connected to the circulation pipe 19 are provided at the respective end portions.

  A plurality of substantially U-shaped heat exchange pipe portions 40, 41 projecting inward from the flange 31 by repeating a plurality of penetrations between the outside and the inside through a plurality of through holes 36 of the flange 31 at an intermediate portion of the heat exchange pipe 32. , 42, 43, and 44, and a plurality of folded pipe portions 45, 46, 47, and 48 that are folded back outside the flange 31 to connect the predetermined heat exchange pipe portions 40 to 44 are formed. Each of the heat exchange pipe portions 40 to 44 is fixed in a liquid-tight manner to each through hole 36 of the flange 31 by brazing or the like.

  In the present embodiment, five heat exchange pipe portions 40 to 44 are used, and among the five heat exchange pipe portions 40 to 44, both end portions of the four heat exchange pipe portions 40 to 43 are flanges 31. The four heat exchanging pipe portions 40 to 43 are arranged in the direction perpendicular to the substantially U-shaped surface, that is, the vertical direction, respectively, and one heat exchanging. The end portions of the pipe portion 44 are respectively penetrated into the upper and lower through holes 36 in the middle row of the flanges 31, and the four heat exchange pipe portions 40 to 43 in which one heat exchange pipe portion 44 is arranged and arranged are arranged. It arrange | positions in the direction which the substantially U-shaped surface cross | intersects with respect to the heat exchange pipe parts 40-43 arrange | positioned and arrange | positioned between inner side, ie, vertical direction.

  Outside the flange 31, one connection pipe portion 38 is connected to one end of the uppermost first heat exchange pipe portion 39, and the other end of the first heat exchange pipe portion 40 and the second heat exchange pipe portion 41. The other end of the second heat exchange pipe part 41 and one end of the third heat exchange pipe part 42 are connected by the folded pipe part 46, and the third heat exchange pipe is connected. The other end of the part 42 and one end of the fourth heat exchange pipe part 43 are connected by a folded pipe part 47, and the other end of the fourth heat exchange pipe part 43 and the fifth heat exchange pipe part 44 vertically oriented One end is connected by a folded pipe portion 48, and the other connection pipe portion 39 is connected to the other end of the fifth heat exchange pipe portion 44.

  A bent portion 49 that is bent toward the upper region in the hot water storage tank 12 is formed at the tips of the heat exchange pipe portions 40 to 43. And by inserting into the heat exchanger attachment port 22 of the hot water storage tank 12 from the bent part 49 side of the tip of these heat exchange pipe parts 40-43, all the heat exchange pipe parts 40-44 are heat exchanger attachment ports. Inserted into the hot water storage tank 12 from 22.

  Next, the operation of the present embodiment will be described.

  In the electric water heater 11, for example, the lower heater 15 is energized in a specific time zone such as a late-night power time zone, and hot water of a predetermined temperature is boiled in the hot water storage tank 12 and stored.

  Hot water stored in the hot water storage tank 12 is adjusted to an appropriate hot water temperature set in advance by, for example, a mixing valve through the hot water supply pipe 14, and is supplied to a hot water supply place.

  When the hot water temperature in the bathtub 18 drops when bathing in the bathtub 18, the circulation pump 20 is operated, and the hot water in the bathtub 18 is inserted into the upper part of the hot water storage tank 12 through the circulation pipe 19. Heat is exchanged between the hot water passing through the heat exchange pipe 32 of the heat exchanger 17 and the hot water stored in the hot water storage tank 12, and the hot water whose temperature has increased due to the heat exchange is returned to the bathtub 18. Thus, the hot water filled in the bathtub 18 is chased away.

  At this time, for example, when the amount of hot water in the bathtub 18 is 200 liters and the hot water temperature is 30 ° C., the memorial time when the hot water temperature is chased up to 40 ° C. It is preferable to take at least 5 minutes in consideration of preventing hot water hot enough to cause burns to return to bathtub 18 because it is short, and within 20 minutes in consideration of preventing longer memorial times. Therefore, the range of 5 to 20 minutes is appropriate, and more preferably, the remedy time is not increased more than necessary after the remedy time is lengthened and the temperature of the hot water returning to the bathtub 18 is reduced. In consideration of the above, a range of 10 to 18 minutes is appropriate.

  Then, the relationship between the length of the heat exchange pipe 32 and the remedy time is measured, and the result is shown in FIG. In this measurement, when the amount of hot water filled in the bathtub 18 is 200 liters and the hot water temperature is 30 ° C., the memorial time taken when the hot water temperature is raised to 40 ° C. is measured. The hot water temperature in the tank 12, the flow rate of hot water circulated between the bathtub 18 and the heat exchange pipe 32, the outer diameter and the inner diameter of the heat exchange pipe 32 were measured under the same conditions.

  When the length of the heat exchange pipe 32 was 5 m and the number of heat exchange pipes was 4, the remedy time A1 was 16 minutes 33 seconds, and the remedy time A2 was 15 minutes 44 seconds. When the length of the heat exchange pipe 32 was 5.2 m and the number of heat exchange pipes was four, the remedy time B1 was 15 minutes 23 seconds and the remedy time B2 was 15 minutes 03 seconds. In the case where the length of the heat exchange pipe 32 was 6 m and the number of the heat exchange pipe parts was 5, the memory time C was 12 minutes 20 seconds. In the case where the length of the exchange pipe 32 was 6.2 m and the number of heat exchange pipe parts was 5, the memorial time D was 11 minutes 13 seconds.

  From this measurement result, it is appropriate that the length of the heat exchange pipe 32 is in the range of 4.5 to 6.5 m, considering that it falls within the range of the tracking time of 10 to 18 minutes. In order to secure a length of 4.5 to 6.5 m, it was confirmed that the number of heat exchange pipe portions was 4 or more.

  With regard to the length of the heat exchange pipe 32, if it is shorter than 4.5 m, sufficient heat exchange performance cannot be obtained, and the remedy time is longer than necessary, and if it is longer than 6.5 m, heat exchange is performed. There is a possibility that the temperature of hot water circulating in the bathtub 18 may become too high due to excessive performance, and it may be difficult to insert and arrange the heat exchange pipe 32 into the hot water storage tank 12 from the heat exchanger mounting port 22. is there.

  Therefore, in the heat exchanger 17 that can be attached to and detached from the hot water storage tank 12, by setting the length of the heat exchange pipe 32 in the range of 4.5 to 6.5 m, sufficient heat exchange performance can be obtained after eliminating the fins. In addition, heat exchange performance suitable for reheating hot water in the bathtub 18 can be obtained. By eliminating the fins, the occurrence of pitting corrosion in the heat exchange pipe 32 can be reduced.

  Moreover, it is preferable to make the outer diameter of the heat exchange pipe 32 into the range of 11-15 mm. That is, if the outer diameter of the heat exchange pipe 32 is smaller than 11 mm, the heat transfer area with the hot water in the hot water storage tank 12 is reduced, and sufficient heat exchange performance cannot be obtained. When the diameter is larger than 15 mm, the heat exchange performance may be too high, and the temperature of hot water circulating in the bathtub 18 may be too high, and the length of the heat exchange pipe 32 is secured to 4.5 to 6.5 m. In some cases, it may be difficult to insert into the heat exchanger mounting port 22.

  Therefore, in the heat exchanger 17 that can be attached to and detached from the hot water storage tank 12, in addition to setting the length of the heat exchange pipe 32 in the range of 4.5 to 6.5 m, the outer diameter of the heat exchange pipe 32 is set to 11 to 15 mm. By setting it as the range, sufficient heat exchange performance can be obtained after eliminating the fins, and heat exchange performance suitable for reheating the hot water in the bathtub 18 can be obtained.

  Further, when the total area of the plurality of through holes 36 of the flange 31 is A and the effective area of the effective surface portion 35 through which the heat exchange pipe 32 of the flange 31 can penetrate is B, the relationship of A / B> 0.16 is established. It is preferable to have.

That is, when there are 10 through holes 36 under the condition that the inner diameter of the through hole 36 of the flange 31 is 12.7 mm and the diameter of the effective surface portion 35 of the flange 31 is 81 mm, (6.35) ² × π × 10 / (40.05) ² × π = 0.25, and when there are eight through holes 36, (6.35) ² × π × 8 / (40.05) ² × π = 0.20, through holes 36 Is 6. (6.35) ² × π × 6 / (40.05) ² × π = 0.15.

  In the measurement described above, it has been confirmed that four or more heat exchange pipe portions are required to secure the length 4.5 to 6.5 m of the heat exchange pipe 32, and therefore the number of through holes 36 is eight. The relationship of A / B> 0.16 is defined so that it is necessary to be more than one and is larger than the value of A / B = 0.15 when there are six through holes 36.

  Therefore, the ratio of the total area A of the plurality of through-holes 36 / the effective area B of the flange 31 is larger than 0.16, and the relationship of A / B> 0.16 is satisfied, so that the flange 31 has a limited size. In particular, it is possible to increase the number of heat exchange pipes that are inserted and arranged in the hot water storage tank 12 through the flange 31 and to secure the necessary length of the heat exchange pipe 32.

  Further, the heat exchange pipe 32 projects both ends of the heat exchange pipe 32 to the outside of the flange 31, and repeats penetration of the intermediate portion of the heat exchange pipe 32 between the outside and inside of the flange 31 a plurality of times. A plurality of substantially U-shaped heat exchange pipe portions 40 to 44 projecting inward are formed, and a plurality of folded pipe portions 45 to 48 that are folded back outside the flange 31 and connect the heat exchange pipe portions 40 to 44 are formed. Accordingly, the necessary length of the heat exchange pipe 32 can be ensured while the plurality of heat exchange pipe portions 40 to 44 can be inserted and disposed in the hot water storage tank 12 from the heat exchanger attachment port 22.

  The heat exchange pipe 32 includes a plurality of substantially U-shaped heat exchange pipe portions 40 to 44, in which a predetermined number of heat exchange pipe portions 40 to 43 are aligned and arranged in a direction perpendicular to the substantially U-shaped surface, and the remaining The direction in which the substantially U-shaped surface intersects the heat exchange pipe parts 40 to 43 arranged between the insides of the predetermined number of heat exchange pipe parts 40 to 43 in which the heat exchange pipe parts 44 are arranged and arranged By arranging in this manner, a plurality of heat exchange pipe portions 40 to 44 can be arranged densely, the number of heat exchange pipe portions 40 to 44 can be increased, and the necessary length of the heat exchange pipe 32 can be ensured.

  By bending the tip of the heat exchange pipe portion 32 toward the upper area in the hot water storage tank 12, the heat of the upper portion of the hot water storage tank 12 can be used effectively.

  It should be noted that the intermediate portion of the heat exchange pipe 32 of the heat exchanger 17 is penetrated and fixed to the flange 31 so that the long heat exchange pipe 32 can be reliably supported, but the intermediate portion of the heat exchange pipe 32 is attached to the flange 31. Instead of penetrating, only the both ends of the heat exchange pipe 32 may be penetrated and supported by the flange 31.

  The heat exchanger 17 is not limited to an electric water heater that boils hot water using the heaters 15 and 16, but can also be applied to an electric water heater that heats hot water using a heat pump unit.

It is a perspective view of the heat exchanger which shows one embodiment of this invention. It is a side view of a heat exchanger same as the above. It is an end face figure of the outside of a heat exchanger same as the above. It is a front view of the flange of a heat exchanger same as the above. It is the block diagram which simplified the hot-water supply apparatus using a heat exchanger same as the above. It is a graph which shows the relationship between the length of a heat exchanger same as the above, and a memorial time.

Explanation of symbols

12 Hot water storage tank
17 Heat exchanger
18 Bathtub
22 Heat exchanger mounting port
31 Flange
32 heat exchange pipe
36 Through hole
40-44 heat exchange pipe section
45-48 Folded pipe part

Claims (6)

A heat exchanger in which hot water circulates between the bath and heat exchange with the hot water in the hot water storage tank,
A flange that is detachably attached to a heat exchanger attachment port formed in the hot water storage tank;
The heat of 4.5 to 6.5 m in length, both ends projecting to the outside of the flange, and the middle part projecting to the inside of the flange and inserted into the hot water storage tank from the heat exchanger mounting port A heat exchanger comprising: an exchange pipe. The heat exchanger according to claim 1, wherein an outer diameter of the heat exchange pipe is 11 to 15 mm. The heat exchange pipe is formed with a plurality of substantially U-shaped heat exchange pipe parts whose both ends protrude to the outside of the flange and the intermediate part repeatedly penetrates between the outside and inside of the flange and protrudes to the inside of the flange. And a plurality of folded pipe portions that are folded back outside the flange to connect the heat exchange pipe portions are formed, and the plurality of heat exchange pipe portions are inserted and arranged in the hot water storage tank from the heat exchanger attachment port. The heat exchanger according to claim 1 or 2. When a plurality of through holes through which the heat exchange pipe passes are formed in the flange, the total area of these through holes is A, and the effective area of the region through which the heat exchange pipe of the flange can penetrate is A / B The heat exchanger according to claim 3, wherein the relationship is> 0.16. The heat exchange pipe includes a plurality of substantially U-shaped heat exchange pipe portions in which a predetermined number of heat exchange pipe portions are arranged in a direction perpendicular to the substantially U-shaped surface, and the remaining heat exchange pipe portions are A substantially U-shaped surface is arranged between the insides of a predetermined number of heat exchange pipe portions arranged in an arrangement so that the substantially U-shaped surfaces intersect with the heat exchange pipe portions arranged in an arrangement. The heat exchanger according to 3 or 4. The heat exchanger according to any one of claims 1 to 5, wherein at least a tip of a part of the heat exchange pipe is bent toward an upper region in the hot water storage tank.

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