JP2010281495A - Latent heat recovery type water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To securely prevent water in an endoergic pipe group of a latent heat exchanger from being frozen even if cold air flows in from an exhaust tube, in a latent heat recovery type water heater communicating with the latent heat exchanging chamber and having the exhaust tube for exhausting combustion exhaust gas in the latent heat exchanging chamber opening to the outside. <P>SOLUTION: The endoergic pipe group 12a in which heated fluid flows is stored in the latent heat exchanging chamber 12, and the latent heat exchanging chamber 12 includes an exhaust inlet 40 to which the combustion exhaust gas is sent and an exhaust outlet 50 for exhausting the combustion exhaust gas to the outside. The exhaust outlet 50 is made to communicate with the exhaust tube 31. The combustion exhaust gas exhausted from the exhaust outlet 50 is emitted from the exhaust tube 31 to ambient air after passing through a narrow exhaust passage Ra formed of an exhaust gas guide plate 25. A composition wall of a casing 22 which forms the most downstream section of the exhaust passage R is provided with a heating device H for warming air in the narrow exhaust passage Ra narrowed by the exhaust gas guide plates 25, 27. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to freeze prevention of a latent heat recovery type water heater provided with a latent heat exchange chamber.

  As shown in FIG. 3, as a condensing type water heater, for example, a combustion chamber 110, a sensible heat exchange chamber 111, and a latent heat exchange chamber 112 are arranged in the instrument main body 100, and the instrument main body 100 has an upper part. As a supply / exhaust cylinder, there is one in which a double pipe 130 composed of an exhaust cylinder 131 and a supply cylinder 132 is protruded.

  A gas burner 119 connected to the gas supply pipe 113 is disposed in the combustion chamber 110, and an air supply fan 114 is provided on the lower plate of the combustion chamber 110. The sensible heat exchange chamber 111 is provided with an endothermic pipe group 111a, and the latent heat exchange chamber 112 is provided with an endothermic pipe group 112a. A water supply pipe 117 is connected to the upstream end of the endothermic pipe group 112a of the latent heat exchange chamber 112, and an upstream end of the endothermic pipe group 111a of the sensible heat exchange chamber 111 is connected to the downstream end of the endothermic pipe group 112a. . A hot water discharge pipe 118 is connected to the downstream end of the heat absorption pipe group 111a.

  The latent heat exchange chamber 112 has an exhaust inlet 140 formed between the drain receiving plate 160 and the constituent wall of the casing 102, and an exhaust outlet 150 formed in the upper constituent wall of the casing 102 connected to the exhaust pipe 131. is doing. As a result, the combustion exhaust after the sensible heat is recovered in the sensible heat exchange chamber 111 is supplied into the latent heat exchange chamber 112 from the exhaust inlet 140 to the latent heat exchange chamber 112. An exhaust passage is formed in which the combustion exhaust after the latent heat is recovered is discharged to the exhaust tube 131 through the exhaust outlet 150.

  The cold water from the water supply pipe 117 is heated and exchanged in the latent heat exchange chamber 112 and the sensible heat exchange chamber 111 while passing through the heat absorption pipe group 112a and the heat absorption pipe group 111a, and becomes hot water. Hot water is supplied to curans in bathrooms and kitchens.

  By the way, in the latent heat recovery type water heater as described above, since water stays in the heat absorption pipe groups 111a and 112a in the non-operating state, the water in the heat absorption pipe groups 111a and 112a is frozen in the winter and the appliance is It may be damaged. In this case, cool air enters from the exhaust tube 131 and the heat absorption pipe group 112a adjacent to the exhaust outlet 150 of the latent heat exchange chamber 112 communicating with the exhaust tube 131 can be cooled most. Therefore, it is preferable to dispose a heating device for preventing freezing in the endothermic pipe group 112a. However, since drain is generated in the latent heat exchange chamber 112, a heating device is directly disposed in the endothermic pipe group 112a. I can't.

Therefore, in the conventional latent heat recovery type water heater, for example, a heating device Ha is disposed in the heat absorption pipe group 111a of the sensible heat exchange chamber 111 to heat the heat absorption pipe group 111a, and the heat absorption pipe group 111a to the heat absorption pipe group 112a. By transferring the heat to the heat sink, freezing of the water staying in the endothermic pipe groups 111a and 112a is prevented (for example, Patent Document 2).
In another conventional latent heat recovery type water heater, a heater serving as a heating device is provided on the outer surface of the casing wall of the latent heat exchange chamber, and the support of the heat absorption pipe group of the latent heat exchange chamber is attached to the casing wall. A part is in contact with the part heated by the heater in the part, and the other part is configured as a heat conducting member in contact with the heat absorbing pipe group (Patent Document 1). According to this, the heat of the heater is transferred from the wall of the casing to the support body, and from the support body to the heat absorption pipe group, thereby preventing freezing of the water retained in the heat absorption pipe group of the latent heat exchange chamber. Yes.

JP 2008-151473 A

JP 2006-46866 A

  However, in the former conventional latent heat recovery type water heater (Patent Document 2), the heat absorption pipe group 111a in the sensible heat exchange chamber 111 to the heat absorption pipe group 112a adjacent to the exhaust outlet 150 of the latent heat exchange chamber 112 are equivalent. The heating by the heating device Ha is only local. Therefore, even if the heating device Ha is provided in the endothermic pipe group 111a, a long time is required until heat is transferred to the endothermic pipe group 112a adjacent to the exhaust outlet 150 of the latent heat exchange chamber 112, and the heat absorption pipe group 112a It was difficult to reliably prevent water from freezing.

  Further, even in the latter conventional latent heat recovery type water heater (Patent Document 1), heat is transferred from the wall portion of the casing to the support body, and from this support body to the heat absorption pipe group in the casing. It took a long time for heat to be transferred to the endothermic pipe group close to the outlet, and it was difficult to reliably prevent the water in the endothermic pipe group from freezing.

  Especially in cold regions, it is not uncommon for the outside temperature to be minus 30 degrees in winter. Therefore, in such a cold region, when the outside air flows back into the exhaust pipe 131 and the cold air enters the latent heat exchange chamber 112, the temperature in the latent heat exchange chamber 112 is rapidly and remarkably lowered. It was difficult to prevent freezing of the water in the endothermic pipe group 112a only by locally heating with a heating device.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to recover latent heat that communicates with a latent heat exchange chamber and that has an exhaust pipe that is open to the outside for exhausting combustion exhaust in the latent heat exchange chamber. An object of the present invention is to ensure that the water in the heat absorption pipe group of the latent heat exchange chamber can be prevented from freezing even if cold air flows from the exhaust pipe in the mold water heater.

The latent heat recovery type water heater according to the present invention is:
A casing having an exhaust inlet to which combustion exhaust is supplied and an exhaust outlet from which the combustion exhaust is exhausted, and an exhaust passage provided in the casing and formed between the exhaust inlet and the exhaust outlet A latent heat exchange chamber having a heat absorption pipe group in which heat exchange is performed with the combustion exhaust by passing exhaust;
A latent heat recovery type water heater comprising an exhaust pipe communicating with the exhaust outlet and exhausting the combustion exhaust from the exhaust outlet to the outside,
The latent heat exchange chamber warms the air in the exhaust guide plate that narrows the exhaust passage in the vicinity of the exhaust outlet that is the most downstream portion of the exhaust passage, and the narrow exhaust passage narrowed by the exhaust guide plate. And a heating device provided on a constituent wall of the casing that forms the most downstream portion of the exhaust passage.

  With the above configuration, it is possible to heat the cold air entering from the exhaust pipe efficiently in the narrow exhaust passage. As a result, even if cold air flows backward from the exhaust pipe communicating with the latent heat exchange chamber in winter, the air heated by the heating device enters the latent heat exchange chamber, so the latent heat that is most likely to freeze Freezing of the water in the heat absorption pipe group close to the exhaust outlet of the heat exchange chamber can be prevented.

In the latent heat recovery type water heater, it is preferable that the heating device is installed over substantially the entire width direction of the outer surface of the constituent wall of the casing.
According to this, the air in the narrow exhaust passage can be uniformly warmed by the heating device. Further, since the heating device is attached to the outer surface of the constituent wall of the casing forming the latent heat exchange chamber, the heating device is not affected by the drain generated in the latent heat exchange chamber.

The latent heat recovery type water heater further includes an exhaust rectifying plate in the narrow exhaust passage, and the heating device is configured to warm the air in the narrow exhaust passage narrowed by the exhaust rectifying plate. It is preferable.
According to this, since the air in the narrow exhaust passage further narrowed by the exhaust rectifying plate can be warmed, the cold air entering from the exhaust pipe can be heated more efficiently.

In the latent heat recovery type water heater, the exhaust pipe further includes a temperature detection means for detecting a temperature in the exhaust pipe, and the heating device is configured such that the temperature detected by the temperature detection means is a predetermined freezing temperature. It is preferable that the air in the narrow exhaust passage is warmed when the temperature falls below the prevention temperature.
According to this, the temperature detection means is provided inside the exhaust pipe communicating with the latent heat exchange chamber, and when the temperature detected by the temperature detection means falls below a predetermined freezing prevention temperature, the heating Since the device warms the air in the narrow exhaust passage, it can reliably detect the temperature of the cool air that cools the endothermic pipe group close to the exhaust outlet of the latent heat exchange chamber that is most likely to freeze, thereby The cold air entering the inside can be heated quickly and reliably.

  As described above, according to the present invention, even if cold air enters from the exhaust pipe exposed to the outside in winter, the cold air remains in the narrow exhaust passage formed at the most downstream portion of the exhaust passage. It is efficiently heated by a heating device. Thereby, the cooling of the heat absorption pipe group close to the exhaust outlet of the latent heat exchange chamber that is most likely to be frozen can be prevented. Therefore, even if the outside air whose temperature has dropped extremely in a cold region flows back into the exhaust pipe, water in the endothermic pipe group in the latent heat exchange chamber can be reliably prevented from being damaged, resulting in damage to the equipment. Can be prevented.

It is a schematic front view which shows an example of the latent heat recovery type water heater of embodiment of this invention. It is a schematic longitudinal cross-sectional view which shows an example of the latent heat recovery type water heater of embodiment of this invention. It is a schematic front view which shows the conventional latent heat recovery type water heater.

  In the following, for the latent heat recovery type water heater of the present embodiment, a forced supply / exhaust type (FF type) in which outdoor air is supplied by operation of an air supply fan and combustion exhaust gas burned by a gas burner is discharged to the outside The hot water heater will be described as an example. FIG. 1 is a schematic front view showing an example of a latent heat recovery type water heater of the present embodiment, and FIG. 2 is a schematic longitudinal sectional view of FIG. This latent heat recovery type water heater is an indoor installation type forced air supply / exhaust type (FF type) water heater, and as shown in FIGS. 1 and 2, the appliance body 1 is attached to an indoor inner wall 4 or the like. A double pipe 30 consisting of an exhaust cylinder 31 and a supply cylinder 32 constituting an air supply / exhaust cylinder protrudes from above the instrument body 1, and an open end (not shown) of the double pipe 30 is It penetrates the inner wall 4 and is open to the outdoors. The exhaust cylinder 31 of the double pipe 30 is an inner cylinder, the supply cylinder 32 is an outer cylinder, and a temperature sensor is provided on the inner surface of the exhaust cylinder 31 as temperature detecting means for detecting the ambient temperature in the exhaust cylinder 31. 33 is arranged. The temperature sensor 33 is connected to a control device (not shown), and the temperature in the exhaust pipe 31 is monitored by the control device. Then, when the temperature detected by the temperature sensor 33 becomes equal to or lower than the freezing prevention temperature (for example, 4 ° C.), the control device activates a heater H described later, and then the temperature detected by the temperature sensor 33 is changed to a stop temperature (for example, When the temperature reaches 7 ° C., the heater H is deactivated.

  In the instrument main body 1, a combustion chamber 10, a sensible heat exchange chamber 11, and a latent heat exchange chamber 12 are accommodated in this order from below. The exhaust cylinder 31 communicates with the latent heat exchange chamber 12, and the supply cylinder 32 includes casings 20, 21, and 22 that form the peripheral walls of the combustion chamber 10, the sensible heat exchange chamber 11, and the latent heat exchange chamber 12, and the instrument body. 1 communicates with the space 16 between the two. Also, below the combustion chamber 10, an air supply fan 14 is attached for taking in combustion air from the supply cylinder 32 into the instrument body 1 and supplying the taken combustion air into the combustion chamber 10. . Inside the sensible heat exchange chamber 11 and the latent heat exchange chamber 12, a copper endothermic pipe group 11a and a corrosion-resistant stainless endothermic pipe group 12a are accommodated, respectively. The upstream end of the endothermic pipe group 12a is connected to the water supply pipe 17, the downstream end of the endothermic pipe group 12a is connected to the upstream end of the endothermic pipe group 11a, and the downstream end of the endothermic pipe group 11a is connected to a hot water supply terminal such as a curan (not shown). The hot water pipe 18 is connected. Further, a drain receiving plate 60 for collecting drain generated when latent heat is absorbed from the combustion exhaust gas in the latent heat exchange chamber 12 is disposed at the bottom of the latent heat exchange chamber 12. The drain receiving plate 60 is formed so as to descend toward the front wall 22 a of the casing 22. Further, a groove-shaped drain receiver 61 is installed at the lower end of the drain receiving plate 60. As a result, the drain that is generated in the latent heat exchange chamber 12 and adheres to the heat absorption pipe group 12a is dropped on the drain receiving plate 60, then flows to the front wall 22a side, is collected in the drain receiver 61, and drained. It is collected in the drain neutralization chamber 63 through the pipe 62. The drain is neutralized in the drain neutralization chamber 63 and then discharged out of the instrument body 1.

  Referring to FIG. 2, an exhaust inlet 40 for sending combustion exhaust gas from sensible heat exchange chamber 11 to latent heat exchange chamber 12 is provided between the rising end of drain receiving plate 60 and rear wall 22 b of casing 22. It is open. Further, a first exhaust guide plate 27 bent toward the rear wall 22b is formed on the upper portion of the front wall 22a of the casing 22, and the front portion of the upper wall 22c of the casing 22 is lowered toward the front wall 22a. Thus, a second exhaust guide plate 25 is formed, which is provided below the first exhaust guide plate 27 of the front wall 22a so as to provide a gap between the front end portion and the front wall 22a. An exhaust outlet 50 for exhausting combustion exhaust is opened by the distal end portion of the first exhaust guide plate 27 and the proximal end portion of the second exhaust guide plate 25, and the exhaust outlet 50 communicates with the exhaust cylinder 31. Yes. As a result, in the vicinity of the exhaust outlet 50 of the latent heat exchange chamber 12, the exhaust passage is narrowed between the first exhaust guide plate 27 and the second exhaust guide plate 25, so that the exhaust passage R in the latent heat exchange chamber 12 can be A narrow exhaust passage Ra is formed in the downstream portion. Therefore, the latent heat exchange chamber 12 and the exhaust pipe 31 are communicated with each other via a narrow exhaust passage Ra having a relatively narrow vertical width, and combustion exhaust gas passes through this narrow exhaust passage Ra. Is discharged to the outside. The second exhaust guide plate 25 is provided with an exhaust rectifier plate 26 for rectifying combustion exhaust during exhaust, which is suspended from the second exhaust guide plate 25 toward the first exhaust guide plate 27. An exhaust passage Ra is further narrowed between the plate 26 and the first exhaust guide plate 27. And the heater H which is a heating apparatus for heating the air in the narrow exhaust passage Ra constitutes a part of the narrow exhaust passage Ra so that the heating surface faces the narrow exhaust passage Ra. It is disposed on the outer surface of the first exhaust guide plate 27. As shown in FIG. 1, three heaters H are installed side by side in the horizontal direction. The heater H is connected to a control device (not shown), and when the temperature detected by the temperature sensor 33 in the exhaust pipe 31 described above is equal to or lower than the anti-freezing temperature, the heater H is detected by a signal from the control device. Is turned on, and the first exhaust guide plate 27 constituting a part of the narrow exhaust passage Ra is heated over substantially the entire region in the lateral direction.

  In this latent heat recovery type water heater, when a user opens a currant (not shown), water supply to the water supply pipe 17 is started. When the water amount sensor S detects the water flow, the air supply fan 14 is activated, and the outside air is taken into the space 16 from the supply cylinder 32 as shown by the broken line arrow in FIG. Air is sent in. As a result, the gas burner 19 in the combustion chamber 10 burns to generate combustion exhaust, and the combustion exhaust is sent to the upper sensible heat exchange chamber 11 and further to the latent heat exchange chamber 12 by the air supply fan 14.

  When combustion exhaust gas is sent into the sensible heat exchange chamber 11, heat exchange is performed between the combustion exhaust gas and the heat absorption pipe group 11a while the combustion exhaust gas passes through the sensible heat exchange chamber 11, and sensible heat is recovered. The Further, the sensible heat is recovered in the sensible heat exchange chamber 11 and the combustion exhaust is further supplied into the latent heat exchange chamber 12 from the exhaust inlet 40 of the latent heat exchange chamber 12 so that the combustion exhaust is between the endothermic pipe groups 12a and the endothermic pipe. Heat is exchanged between the combustion exhaust and the heat absorbing pipe group 12a while being exhausted from the exhaust outlet 50 via the exhaust passage R formed by the group 12a and the constituent walls of the casing 22, and latent heat is recovered. The Thus, the combustion exhaust gives its sensible heat to the endothermic pipe group 11a of the sensible heat exchange chamber 11 and further to the latent heat to the endothermic pipe group 12a of the latent heat exchange chamber 12, so that the sensible heat exchange chamber 11 The endothermic pipe group 11a and the endothermic pipe group 12a of the latent heat exchange chamber 12 are heated, and the water flowing in the endothermic pipe groups 11a and 12a becomes hot water, and hot water is discharged from a hot water supply terminal such as a currant.

  Although the water heater is of an indoor installation type, the exhaust cylinder 31 is open to the outside air together with the supply cylinder 32, so that the air in the exhaust cylinder 31 and the supply cylinder 32 directly affects the outside air temperature when not in operation. receive. Therefore, in the winter season, when the outside air temperature decreases, cold air enters from the exhaust pipe 31, enters the latent heat exchange chamber 12 through the exhaust outlet 50 communicating with the exhaust pipe 31, and is located near the exhaust outlet 50. The group 12a is cooled, and the water in the endothermic pipe group 12a is easily frozen. In particular, when the inside of the appliance main body 1 becomes a negative pressure or the outside air is blown into the exhaust pipe 31 by using a ventilation fan or heating indoors, as shown by a solid line arrow in FIG. As a result, the outside air C flows backward, whereby the ambient temperature in the exhaust pipe 31 decreases, and the heat absorption pipe group 12a in the latent heat exchange chamber 12 can be cooled.

  However, in the latent heat recovery type water heater of the present embodiment, the latent heat exchange chamber 12 includes the first exhaust guide plate 27 and the first exhaust guide plate 27 that narrow the exhaust passage R in the vicinity of the exhaust outlet 50 that is the most downstream portion of the exhaust passage R. 2 An exhaust guide plate 25 is provided, and a heater H is provided on the outer surface of the first exhaust guide plate 27 of the front wall 22a that forms the most downstream portion of the narrow exhaust passage R over substantially the entire width direction. Yes. The heater H is activated when the temperature detected by the temperature sensor 33 provided in the exhaust cylinder 31 is equal to or lower than the anti-freezing temperature, so that the cold air is latent heat from the exhaust cylinder 31 through the exhaust outlet 50. Even if it enters the heat exchange chamber 12, the narrow exhaust passage Ra is heated by the heater H, and the cold air in the narrow exhaust passage Ra can be efficiently heated. In particular, since the heating surface of the heater H is directed toward the narrow exhaust passage Ra further narrowed by the exhaust rectifying plate 26, cold air passes between the exhaust rectifying plate 26 and the first exhaust guide plate 27. In the meantime, this cold air can be heated. Therefore, even if the cold air flows back into the exhaust pipe 31, the cold air is heated by the heater H when it passes through the narrow exhaust passage Ra, and becomes warm air. Therefore, the endothermic pipe group of the latent heat exchange chamber 12 Freezing of the water in 12a can be prevented. And since the heater H is attached to the outer surface of the 1st exhaust guide plate 27 of the front wall 22a of the casing 22 which forms the latent heat exchange chamber 12, the heater H is the drain produced | generated in the latent heat exchange chamber 12 There is no risk of being affected.

(Other embodiments)
(1) In the above embodiment, the temperature sensor 33, which is a temperature detecting means, is provided in the exhaust pipe 31, but the arrangement position is not particularly limited. For example, in the forced air supply / exhaust water heater, since the supply cylinder 32 communicates with the outside in order to supply combustion air from the outside, temperature detection means may be provided in the supply cylinder 32.

(2) In the above embodiment, the heater H is provided on the first exhaust guide plate 27 on the front wall 22a of the casing 22 that forms the latent heat exchange chamber 12, but forms the most downstream portion of the exhaust passage R. The arrangement position is not particularly limited as long as it is provided on the constituent wall of the casing. For example, the heater H serving as a heating device may be provided on the outer surface of the second exhaust guide plate 25 on the upper wall 22 c of the casing 22. Further, the heater H serving as a heating device may be provided on both the front wall 22a and the upper wall 22c, which are constituent walls of the casing 22.

(3) In the above embodiment, the double pipe 30 composed of the exhaust cylinder 31 and the supply cylinder 32 is provided. However, the two pipes in which the exhaust cylinder 31 and the supply cylinder 32 protrude separately are provided. May be used. In addition, the present invention is not limited to the FF type water heater, but can be applied to a water heater in which the latent heat exchange chamber can be cooled by outside air through the exhaust pipe.

DESCRIPTION OF SYMBOLS 10 Combustion chamber 11 Sensible heat exchange chamber 12 Latent heat exchange chamber 12a Endothermic pipe group 14 Blower fan 22 Casing 22a Configuration wall (front wall)
25 Second exhaust guide plate 26 Exhaust flow straightening plate 27 First exhaust guide plate 31 Exhaust tube 33 Temperature sensor 50 Exhaust outlet 40 Exhaust inlet H Heating device (heater)
R Exhaust passage Ra Narrow exhaust passage

Claims (4)

A casing having an exhaust inlet to which combustion exhaust is supplied and an exhaust outlet from which the combustion exhaust is exhausted, and an exhaust passage provided in the casing and formed between the exhaust inlet and the exhaust outlet A latent heat exchange chamber having a heat absorption pipe group in which heat exchange is performed with the combustion exhaust by passing exhaust;
A latent heat recovery type water heater comprising an exhaust pipe communicating with the exhaust outlet and exhausting the combustion exhaust from the exhaust outlet to the outside,
The latent heat exchange chamber warms the air in the exhaust guide plate that narrows the exhaust passage in the vicinity of the exhaust outlet that is the most downstream portion of the exhaust passage, and the narrow exhaust passage narrowed by the exhaust guide plate. A latent heat recovery type water heater having a heating device provided on a constituent wall of a casing forming the most downstream portion of the exhaust passage. In the latent heat recovery type water heater according to claim 1,
The heating device is a latent heat recovery type water heater installed over substantially the entire width direction of the outer surface of the constituent wall of the casing. In the latent heat recovery type water heater according to claim 1,
An exhaust air rectifying plate in the narrow exhaust passage;
The heating device is a latent heat recovery type hot water heater configured to warm air in a narrow exhaust passage narrowed by the exhaust current plate. In the latent heat recovery type water heater according to any one of claims 1 to 3,
The exhaust pipe further has a temperature detection means for detecting the temperature in the exhaust pipe,
The heating device is a latent heat recovery type hot water heater configured to warm air in the narrow exhaust passage when the temperature detected by the temperature detection means is equal to or lower than a predetermined freezing prevention temperature.

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