JP2010139110A - Latent heat recovery type heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a latent heat recovery type heat exchanger with improved heat efficiency. <P>SOLUTION: The latent heat recovery type heat exchanger 5 is formed with a lateral passage 500 for guiding gas combustion exhaust gas from an exhaust gas inlet 501 of a casing 50 to an exhaust gas outlet 502. Inside the lateral passage 500, two or more heat sink pipes 51 extending to a direction of crossing a flow of the combustion exhaust gas are laterally installed. Among a plurality of clearances between vertically-aligned adjacent heat sink pipes 51 on the exhaust gas inlet 501 side of the lateral passage 500, the undermost clearance C1 is set to be wider than the topmost clearance A1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a latent heat recovery type heat exchanger that condenses water vapor contained in combustion exhaust gas on the surface of the heat absorption tube and recovers latent heat from the combustion exhaust gas, particularly latent heat recovery type heat incorporated in a water heater or a bath tub. It relates to an exchanger.

  In a conventional latent heat recovery type heat exchanger (hereinafter referred to as “latent heat exchanger”) incorporated in a water heater or a bath tub, a plurality of heat absorption tubes are fixed between the side walls of the lateral passage formed in the casing. The thing of the structure installed horizontally by the space | interval is employ | adopted widely (for example, refer patent document 1).

  FIG. 5 is a schematic vertical sectional view of a water heater 8 provided with the above-described conventional latent heat exchanger 9, and the water sent to the heat absorption pipe 91 of the latent heat exchanger 9 is a heat exchanger for sensible heat recovery. The heat exhaust pipe 41 (hereinafter referred to as “sensible heat exchanger”) 4 is led to a hot water supply destination P such as a currant or a bathtub, while the combustion exhaust gas produced by the burner 3 is subjected to sensible heat exchange. It is configured to be led to the latent heat exchanger 9 side through the gap between the heat absorption tubes 41 of the vessel 4.

  The latent heat exchanger 9 is formed by forming a transverse passage 900 extending in the front-rear direction in the casing 90 and housing a plurality of heat absorption tubes 91 in the transverse passage 900. The cylindrical can body 40 to be accommodated is provided on the upper end open portion 402 side.

  An exhaust inlet 901 that connects the lateral passage 900 and the internal space of the can body 40 is opened at the bottom rear portion of the casing 90, and passes through the gap between the heat absorption tubes 41 of the sensible heat exchanger 4. The combustion exhaust gas guided to the upper end opening 402 is guided from the exhaust inlet 901 to the back side of the lateral passage 900.

  In addition, an exhaust outlet 902 that connects the lateral passage 900 and the outside of the water heater 8 is opened in the upper front portion of the casing 90, and combustion exhaust gas that is fed into the lateral passage 900 is disposed between the heat absorption pipes 91. After being led to the front side of the lateral passage 900, the exhaust is discharged from the exhaust outlet 902 to the outside.

A plurality of heat absorption pipes 91 are provided between the side walls in the horizontal passage 900, and each extend in a direction intersecting with the flow of combustion exhaust introduced into the horizontal passage 900. The plurality of endothermic tubes 91 installed in the horizontal passage 900 are arranged in a staggered vertical section, and the gaps S between the endothermic tubes 91 arranged vertically are all uniform. Is set.
As a result, the combustion exhaust gas fed into the lateral passage 900 from the exhaust inlet 901 efficiently contacts the surface of each endothermic tube 91 while passing through the lateral passage 900, so that the thermal efficiency is good.
JP 2008-032369 A

  However, the combustion exhaust gas sent from the exhaust inlet 901 to the horizontal passage 900 has a relatively high temperature, and therefore tends to be guided to the upper region of the horizontal passage 900. For this reason, in the above-mentioned conventional configuration in which the gaps S between the heat absorption tubes 91 are all set uniformly, the combustion exhaust gas fed into the lateral passage 900 passes through the upper region in the lateral passage 900 from the exhaust outlet 902. The heat absorption capacity of the entire heat absorption tube 91 group discharged and disposed in the lateral passage 900 was not sufficiently exhibited.

  The present invention has been made in view of the above points, and provides a latent heat recovery type heat exchanger that further improves thermal efficiency by exhibiting the heat absorption capability of the entire heat absorption tube group disposed in the lateral passage. The task is to do.

In the latent heat recovery type heat exchanger according to the present invention, a lateral passage for guiding the combustion exhaust of gas from the exhaust inlet of the casing to the exhaust outlet is formed, and a plurality of extending in a direction intersecting the flow of the combustion exhaust is formed in the lateral passage. A latent heat recovery type heat exchanger in which an endothermic tube is horizontally installed,
Among the plurality of gaps between the heat absorption tubes arranged vertically on the exhaust inlet side of the horizontal passage, the lowest gap is set wider than the highest gap.

  According to the above configuration, in the exhaust inlet side region of the endothermic tube group disposed in the horizontal passage, the lower region has a lower ventilation resistance than the upper region, so that the heat absorption tube group is fed into the side passage at the exhaust inlet side. The high-temperature combustion exhaust gas is guided to the lower region side without being biased toward the upper region side in the lateral passage. Thereby, the heat absorption capability of the whole heat absorption tube group arrange | positioned in a horizontal channel | path is exhibited efficiently.

  In addition, among the plurality of gaps between the endothermic tubes arranged vertically on the exhaust inlet side of the lateral passage, the lowermost gap is set wider than the uppermost gap, so that when the latent heat is recovered from the combustion exhaust, Since the drain adhering to the surface does not easily accumulate in the lowest gap, it is possible to suppress a decrease in the exhaust amount from the exhaust outlet due to the drain accumulation.

  In the above-described configuration, it is desirable that the plurality of gaps between the heat absorption tubes arranged vertically on the exhaust inlet side of the horizontal passage are set to be gradually widened from the top to the bottom.

  In this case, in the exhaust inlet side region of the endothermic tube group disposed in the horizontal passage, the ventilation resistance gradually decreases from the upper region to the lower region, so that it is fed to the exhaust inlet side of the horizontal passage. The high-temperature combustion exhaust gas spreads uniformly throughout the entire side passage. Thereby, the heat absorption capability of the whole heat absorption tube group arrange | positioned in a horizontal channel | path is exhibited more efficiently.

  In the above-described configuration, the remotest gap may be set wider than the gap closest to the exhaust outlet among the plurality of gaps between the endothermic tubes arranged vertically on the exhaust outlet side of the horizontal passage.

  In this case, in the exhaust outlet side region of the endothermic tube group disposed in the horizontal passage, the ventilation resistance in the remote area is smaller than the ventilation resistance in the region close to the exhaust outlet, so that it is fed into the horizontal passage. Exhaust combustion exhaust gas is discharged from the exhaust outlet through a remote area without being biased to an area close to the exhaust outlet. Thereby, the heat absorption capability of the whole heat absorption tube group arrange | positioned in a horizontal channel | path is exhibited more efficiently.

  In this case, it is desirable to set a plurality of gaps between the heat absorption tubes arranged vertically on the exhaust outlet side of the side passage in a stepwise manner from the position closest to the exhaust outlet to the remotest position.

  In this case, in the exhaust outlet side region of the endothermic tube group disposed in the lateral passage, the ventilation resistance decreases stepwise as it moves away from the position closest to the exhaust outlet, so that it is fed into the lateral passage. The combustion exhaust gas uniformly passes through the entire area on the exhaust outlet side and is discharged from the exhaust outlet. Thereby, the heat absorption capability of the whole heat absorption tube group arrange | positioned in a horizontal channel | path is exhibited more efficiently.

Since the present invention has the above configuration, the present invention has the following specific effects.
By guiding the high-temperature combustion exhaust gas sent to the exhaust passage side of the side passage to the upper side and the lower side of the side passage, the heat absorption capacity of the entire endothermic tube group in the side passage is efficiently exhibited. Therefore, thermal efficiency is improved.

Next, the best mode for carrying out the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic vertical cross-sectional view of a water heater 1 provided with a latent heat exchanger 5 according to an embodiment of the present invention. Inside the exterior case 10, the exterior case 10 is inserted into a case 30 described later. An air supply fan 2 that sends in external air, a burner 3 that burns gas, a sensible heat exchanger 4 that recovers sensible heat from the combustion exhaust gas generated by the burner 3, and recovers latent heat from the combustion exhaust. The latent heat exchanger 5 is accommodated.

  The burner 3 is incorporated in a rectangular box-shaped housing 30 whose upper surface is open, and a discharge port of the air supply fan 2 is connected to the bottom of the housing 30. The sensible heat exchanger 4 is incorporated in a rectangular tubular can 40 extending upward from the upper surface of the housing 30. Accordingly, the combustion exhaust gas generated by the burner 3 is guided into the can 40 together with the air fed into the housing 30 by the air supply fan 2, and the heat absorption tubes 41, which will be described later, of the sensible heat exchanger 4. Is guided to the upper end open portion 402 side of the can body 40.

  The sensible heat exchanger 4 includes a plurality of heat absorption fins (not shown) and a plurality of heat absorption tubes 41 penetrating the heat absorption fins, and one end side of the heat absorption tubes 41 is connected to the hot water supply destination P, and the other end. The side is connected to one end side of a heat absorption pipe 51 to be described later of the latent heat exchanger 5. Therefore, the hot water sent to the sensible heat exchanger 4 through the latent heat exchanger 5 collects sensible heat from the combustion exhaust in the heat absorption pipe 41 and is supplied to the hot water supply destination P.

  The latent heat exchanger 5 has a rectangular box-shaped casing 50 formed with a transverse passage 500 extending in the front-rear direction, and a plurality of heat absorption tubes 51 accommodated in the transverse passage 500. The upper end of the can 40 is connected to the above.

  An exhaust inlet 501 connected to the upper end opening 402 of the can body 40 is opened at the rear portion of the bottom plate 52 of the casing 50, and the lateral passage 500 is connected to the internal space of the can body 40 through the exhaust inlet 501. ing. Therefore, the combustion exhaust guided to the upper end open portion 402 side of the can body 40 is guided from the exhaust inlet 501 to the exhaust inlet 501 side (back side) of the lateral passage 500.

  An exhaust outlet 502 connected to the outside of the exterior case 10 is opened at the approximate center of the front plate 53 of the casing 50. Further, on the exhaust outlet 502 side (front side) of the lateral passage 500 inside the casing 50 of the exhaust outlet 502. An exhaust passage 54 extending to the lower space on the side) is formed. A guide plate 56 is formed on the back surface of the top plate 55 of the casing 50 so as to extend to the upper edge of the inlet 540 of the exhaust passage 54 through the front side of the heat absorption pipe 51. Accordingly, the combustion exhaust guided to the side of the exhaust inlet 501 of the horizontal passage 500 passes through the gap between the heat absorption pipes 51 and extends along the upper surface of the guide plate 56 and the bottom plate 52 of the casing 50 to the exhaust outlet 502 in the horizontal passage 500. It is led to the lower area of the side (front side). Further, the gas is guided from the inlet 540 of the exhaust passage 54 to the exhaust outlet 502 through the exhaust passage 54 and discharged outside the apparatus.

  As shown in FIG. 2, the heat absorption pipe 51 of the latent heat exchanger 5 is a substantially M-shaped tube body obtained by bending a metal bellows pipe at a predetermined length of about 180 degrees, A plurality (eight in this case) are provided so as to meander between the side walls 57 in 500, and extend in a direction intersecting with the flow of combustion exhaust gas fed into the lateral passage 500. In addition, these heat absorption tubes 51 are arranged in a state where they are vertically overlapped so that the cross sections thereof are staggered in a longitudinal sectional view (see FIG. 1).

  As shown in FIG. 2, both ends of the heat absorption pipe 51 pass through one side wall 57 of the casing 50, and each pipe connection portion of the water inlet side header 58 a and the water outlet side header 58 b fixed to the outer surface of the side wall 57. One end side is connected to the water supply via the water inlet side header 58a, and the other end is connected to one end side of the heat absorption pipe 41 of the sensible heat exchanger 4 via the water outlet side header 58b. Therefore, the hot water sent from the water supply to the latent heat exchanger 5 is sent to the sensible heat exchanger 4 after recovering latent heat from the combustion exhaust gas in the heat absorption pipe 51.

  Further, as shown in FIG. 3, a plurality (three in this case) of gaps A1, B1, and C1 between the endothermic tubes 51 arranged vertically on the side of the exhaust passage 501 closest to the exhaust passage 501 are from the top to the bottom. Widely set in stages. That is, in the region on the exhaust inlet 501 side of the heat absorption pipe 51 group disposed in the horizontal passage 500, the lower region has a lower ventilation resistance than the upper region.

  Specifically, among the gaps A1, B1, and C1 on the exhaust inlet 501 side, the lowest gap C1 is approximately 1.3 times the upper gap (medium gap) B1 and the middle gap B1. Is set to a size approximately 1.3 times as large as the upper gap (uppermost gap) A1, and the intermediate gap B1 from the uppermost gap A1 to which the combustion exhaust gas having a high temperature is easily guided, and the lowest The airflow resistance is gradually reduced in the order of the gap C1.

  Further, a plurality (three in this case) of gaps A2, B2, and C2 between the heat absorption tubes 51 arranged vertically on the side of the exhaust passage 502 closest to the exhaust passage 502 are from the lowest position closest to the entrance 540 of the exhaust passage 54. It is arranged so as to gradually widen to the remotest highest level. That is, in the region of the heat absorption pipe 51 group disposed in the lateral passage 500 on the side of the exhaust outlet 502, the ventilation resistance in the remote area is smaller than the ventilation resistance in the area close to the exhaust outlet 502. Yes.

  Specifically, of the gaps A2, B2, and C2 on the exhaust outlet 502 side, the uppermost gap C2 is approximately 1.3 times the lower gap (medium gap) B2, and the middle gap B2. Is set to approximately 1.3 times the lower gap (lowermost gap) A2, and the middle gap B2 and the uppermost gap C2 from the lowest gap A2 where the combustion exhaust gas is relatively easily discharged are set. In this order, the ventilation resistance is reduced step by step.

  According to this, the combustion exhaust sent from the exhaust inlet 501 to the rear side in the lateral passage 500 does not bias toward the uppermost gap A1 side on the exhaust inlet 501 side, and the lowermost gap having a smaller ventilation resistance than that. Since it is guided to the front side of the lateral passage 500 through C1 and the middle gap B1 side, the combustion exhaust gas spreads over the entire group of heat absorption pipes 51 disposed in the lateral passage 500. As a result, the endothermic capacity of the endothermic tube 51 group is efficiently exhibited, and the thermal efficiency is improved.

  Further, in the region of the heat absorption pipe 51 group disposed in the horizontal passage 500 on the side of the exhaust inlet 501, the ventilation resistance is gradually reduced from the upper region to the lower region. Since the high-temperature combustion exhaust gas sent to the inlet 501 side uniformly spreads over the entire area of the lateral passage 500, the heat absorption capability of the heat absorption tubes 51 group is more efficiently exhibited. Accordingly, the thermal efficiency is further improved.

  Further, since the lowermost gap C1 is set wider than the uppermost gap A1, the drain adhering to the surface of each endothermic tube 51 when collecting latent heat from the combustion exhaust gas is unlikely to collect in the lowermost gap C1. Therefore, it is possible to suppress a decrease in the exhaust amount from the exhaust outlet 502 due to the drain pool.

  On the other hand, the combustion exhaust gas fed into the lateral passage 500 is not biased toward the lowermost gap A2 near the inlet 540 of the exhaust passage 54, and the uppermost gap C2 and the middle gap B2 having a smaller airflow resistance. Since the exhaust gas passes through the side and is led into the exhaust passage 54, the combustion exhaust gas further spreads to the entire heat absorption pipe 51 group disposed in the side passage 500. As a result, the endothermic capacity of the endothermic tube 51 group is exhibited more efficiently, and the thermal efficiency is further improved.

  Further, in the region on the exhaust outlet 502 side of the endothermic pipe 51 group disposed in the horizontal passage 500, the ventilation resistance is gradually reduced from the lower region to the upper region, thereby entering the horizontal passage 500. The sent combustion exhaust gas uniformly passes through the entire area on the exhaust outlet 502 side and is discharged from the exhaust outlet 502, so that the heat absorbing ability of the heat absorbing pipe 51 group is more efficiently exhibited. Accordingly, the thermal efficiency is further improved.

  In the latent heat exchanger 5, as shown in FIG. 4 (a), a heat absorption tube 51 in which a single tube is meandered horizontally is used, and the plurality of heat absorption tubes 51 are arranged in the direction in which combustion exhaust flows. The gaps A1, B1, C1 on the exhaust inlet 501 side and the gaps A2, B2, C2 on the exhaust outlet 502 side are set to have non-uniform dimensions by arranging them at different angles. As shown in b), the plurality of heat absorption pipes 51 described above are juxtaposed at the same angle with respect to the flow direction of the combustion exhaust, and the bent pipe portion R1 on the exhaust inlet 501 side is bent downward, and the exhaust outlet 502 side The bent pipe portion R2 may be bent upward so that the gaps A1, B1, C1 on the exhaust inlet 501 side and the gaps A2, B2, C2 on the exhaust outlet 502 side may be set to non-uniform dimensions. .

  In this case, since the gaps between the endothermic pipes 51 other than the gaps A1, B1, C1 on the exhaust inlet 501 side and the gaps A2, B2, C2 on the exhaust outlet 502 side are uniformly arranged, the combustion exhaust is discharged into the exhaust inlet. From passing through the gaps A1, B1 and C1 on the 501 side to passing through the gaps A2, B2 and C2 on the exhaust outlet 502 side, it is difficult for excessive turbulent flow to occur around each of the endothermic pipes 51. Since the entire surface of 51 is stably contacted, the thermal efficiency is further improved.

  Further, the gaps A2, B2, and C2 on the exhaust outlet 502 side in the latent heat exchanger 5 are configured to be wider on the upper side than the lower side (see FIG. 3), but on the lower side from the upper side. You may comprise so that one may become wider. In this case, since the lowermost gap A2 is set wider than the uppermost gap C2, the drain hardly accumulates in the lowermost gap A2. Therefore, it is possible to suppress a decrease in the exhaust amount from the exhaust outlet 502 due to the drain pool.

  When the gaps A2, B2, and C2 on the exhaust outlet 502 side are configured so that the lower side is wider than the upper side, the inlet 540 of the exhaust passage 54 is the upper space on the exhaust outlet 502 side of the lateral passage 500. It is preferable to provide in. According to this, the combustion exhaust gas fed into the lateral passage 500 is not biased toward the uppermost gap C2 near the inlet 540 of the exhaust passage 54, and the lowermost gap A2 and the middle Since the gap B2 is also led into the exhaust passage 54, the thermal efficiency is further improved as in the above embodiment.

The longitudinal cross-sectional schematic of the water heater 1 provided with the latent heat exchanger 5 which concerns on embodiment of this invention. Schematic cross-sectional view of latent heat exchanger 5 according to an embodiment of the present invention The schematic block diagram of the latent heat exchanger 5 which concerns on embodiment of this invention The right side view (a) showing the arrangement state of the heat absorption tubes 51 of the latent heat exchanger 5 according to the embodiment of the present invention and the arrangement state of the heat absorption tubes 51 of the latent heat exchanger 5 according to another embodiment of the present invention. Right side view showing (b) Longitudinal cross-sectional schematic view of a water heater 8 provided with a conventional latent heat exchanger 9

Explanation of symbols

5 ... Latent heat recovery type heat exchanger 50 ... Casing 500 ... Transverse passage 501 ... Exhaust inlet 502 ... Exhaust outlet 51 ... Endothermic pipe A1 ... Top gap C1 ...・ Lowest gap

Claims (4)

A transverse passage is formed to guide the combustion exhaust of gas from the exhaust inlet of the casing to the exhaust outlet, and a plurality of heat absorption tubes extending in a direction intersecting with the flow of the combustion exhaust are provided in the transverse passage. An exchanger,
A latent heat recovery type heat exchanger characterized in that the lowermost gap is set wider than the uppermost gap among a plurality of gaps between heat absorption tubes arranged vertically on the exhaust inlet side of the horizontal passage. In the latent heat recovery type heat exchanger according to claim 1,
A latent heat recovery type heat exchanger characterized in that a plurality of gaps between endothermic tubes arranged vertically on the exhaust inlet side of the horizontal passage are set to be wide in steps from the highest to the lowest. In the latent heat recovery type heat exchanger according to claim 1 or 2,
Latent heat recovery heat exchanger characterized in that the remotest gap is set wider than the gap closest to the exhaust outlet among the plurality of gaps between the heat absorption tubes arranged vertically on the exhaust outlet side of the horizontal passage. . In the latent heat recovery type heat exchanger according to claim 3,
A latent heat recovery type heat exchanger characterized in that a plurality of gaps between heat absorption tubes arranged vertically on the exhaust outlet side of the side passage are set in a stepwise manner from the position closest to the exhaust outlet to the remotest position. .

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