JP2023147759A - Latent heat recovery-type heat exchanger - Google Patents

Abstract

To reduce pressure loss at an inlet portion of an exhaust cylinder and to prevent a combustion exhaust gas from flowing to a roof of eaves edge where a latent heat recovery-type heat exchanger is installed.SOLUTION: In a latent heat recovery-type heat exchanger including a housing 1 having a heat exchange chamber 11 in which a combustion exhaust gas flows from a rear part to a front part, and a plurality of heat absorption pipes 2 disposed in the heat exchange chamber 11, the exhaust cylinder 3 is mounted on a front plate portion 1b of the housing 1, a guide plate 6 having a suspended plate portion 62 for guiding flow of the combustion exhaust gas downward and an inclined plate portion 63 inclined forward and upward from a lower end of the suspended plate portion 62 and extending forward is disposed on a front end portion of the heat exchange chamber 11, and an exhaust channel 3a is defined between a first straightening member 31 and a second straightening member 32 in the exhaust cylinder 3. The exhaust channel 3a is formed in a manner that its rear portion 3ar is inclined forward and upward and its front portion 3af is substantially horizontal. Preferably, a substantially horizontal second exhaust channel 3b positioned at a lower part of the exhaust channel 3a, is defined in the exhaust cylinder 3.SELECTED DRAWING: Figure 2

Description

The present invention includes a housing having an internal heat exchange chamber through which combustion exhaust gas flows from the rear to the front, and a plurality of heat absorption pipes arranged in the heat exchange chamber, and collects latent heat held by the combustion exhaust gas and transfers it to the heat absorption pipes. This invention relates to a latent heat recovery type heat exchanger that heats flowing water.

Originally, in this type of latent heat recovery type heat exchanger, an exhaust pipe is generally attached to the front plate of the casing, into which combustion exhaust gas flows through an exhaust port provided in the front plate. Conventionally, in this type of latent heat recovery type heat exchanger, a hanging plate part is provided at the front end of the heat exchange chamber and hangs down from the upper surface of the heat exchange chamber to guide the flow of combustion exhaust gas downward. A guide plate is provided that has an inclined plate section that extends forward from the lower end of the hanging plate section, and the combustion exhaust gas is drained from drain water (strongly acidic water generated when moisture in the combustion exhaust gas condenses on the outer surface of the heat absorption pipe). There is a known device that can prevent water from flowing straight into the exhaust stack while containing droplets (for example, see Patent Document 1).

Here, when the guide plate is provided, the combustion exhaust gas that has passed through the lower end of the hanging plate portion flows in a direction that is inclined forward and upward along the inclined plate portion. Therefore, in the conventional example described above, a first rectifying member and a second rectifying member below the first rectifying member are provided in the exhaust stack, and before the combustion exhaust gas flows between the first and second rectifying members, An upwardly sloping exhaust flow path is defined. According to this, the combustion exhaust gas flowing in a direction inclined forwardly upward along the inclined plate portion flows into the exhaust flow path without changing its direction significantly, and the pressure loss at the exhaust pipe inlet portion is reduced. Therefore, the rotational speed of the combustion fan required to properly discharge combustion exhaust gas is reduced, and fan noise can be reduced.

However, in the above-mentioned conventional example, the combustion exhaust gas is discharged to the outside of the exhaust stack while maintaining the upwardly inclined direction. As a result, combustion exhaust gas continues to hit the roof of the eaves where the heat source device incorporating the latent heat recovery type heat exchanger is installed, causing deterioration and damage due to condensation.

Japanese Patent Application Publication No. 2007-232289

In view of the above points, the present invention provides a latent heat recovery type heat exchanger that can reduce the pressure loss at the exhaust pipe inlet and prevent combustion exhaust gas from hitting the roof of the eaves. is the issue.

In order to solve the above problems, the present invention includes a housing having an internal heat exchange chamber through which combustion exhaust gas flows from the rear to the front, and a plurality of heat absorption pipes arranged in the heat exchange chamber, so that the combustion exhaust gas has This is a latent heat recovery type heat exchanger that recovers latent heat to heat the water flowing through the heat absorption pipe, and combustion exhaust gas flows into the front plate of the casing through the exhaust port opened in the front plate. The exhaust stack is attached to the front end of the heat exchange chamber, including a hanging plate part that hangs down from the top surface of the heat exchange chamber and guides the flow of combustion exhaust gas downward, and a hanging plate part that extends forward from the lower end of the hanging plate part. A guide plate having an inclined plate portion extending forward is provided, and a first rectifying member and a second rectifying member below the first rectifying member are provided in the exhaust pipe. A first exhaust flow path through which combustion exhaust gas flows is defined between both the first and second rectifying members, and the first exhaust flow path has a rear portion inclined upward toward the front and a front portion substantially horizontal. characterized by something.

According to the present invention, since the rear part of the first exhaust flow path is inclined forwardly upward, the combustion exhaust gas flowing in the forwardly upwardly inclined direction along the inclined plate part of the guide plate does not change its direction significantly. It flows into the first exhaust flow path, and the pressure loss at the exhaust pipe inlet becomes small. Therefore, the rotation speed of the combustion fan can be lowered to reduce fan noise. Furthermore, since the front portion of the first exhaust flow path is approximately horizontal, the direction in which the combustion exhaust gas is discharged from the exhaust stack is approximately horizontal. Therefore, it is possible to prevent combustion exhaust gas from hitting the roof of the eaves where the heat source device incorporating the latent heat recovery type heat exchanger is installed.

Further, in the present invention, it is desirable that a substantially horizontal second exhaust flow path is defined in the exhaust pipe, which is located below the first exhaust flow path and extends from the front to the rear. According to this, even if the cross-sectional area of each of the first and second exhaust flow paths is narrowed, the pressure loss of the exhaust pipe as a whole can be kept small. By narrowing the cross-sectional area of each exhaust flow path, it is possible to obtain an exhaust sound damping effect, which is useful for noise suppression. Note that the direction of the combustion exhaust gas flowing into the second exhaust flow path is substantially horizontal and in the same direction as the second exhaust flow path, so that pressure loss does not increase.

Further, it is desirable that the lower surface of the second exhaust flow path be located above the lower end of the exhaust port. According to this, it is possible to effectively suppress drain water from entering the second exhaust flow path from the exhaust port.

FIG. 1 is a perspective view of a latent heat recovery type heat exchanger according to an embodiment of the present invention. FIG. 2 is a cut side view taken along line II-II in FIG. 1; 3 is a sectional view taken along line III-III in FIG. 2. FIG. FIG. 2 is an exploded perspective view showing the mounting structure of the exhaust stack in the latent heat recovery type heat exchanger of the embodiment.

Referring to FIGS. 1 and 2, a latent heat recovery heat exchanger A according to an embodiment of the present invention has a heat exchange chamber 11 in which combustion exhaust gas flows from the rear to the front (from the right to the left in FIG. 2). A plurality of heat absorption pipes 2 arranged in a heat exchange chamber 11 are provided. Then, the latent heat possessed by the combustion exhaust gas is recovered to heat the water flowing into the heat absorption pipe 2.

The rear plate part 1a of the housing 1 is provided with an inlet 12 through which combustion exhaust gas that has passed through a sensible heat recovery type heat exchanger (not shown) flows in, and the front plate part 1b of the housing 1 is provided with a heat exchange chamber. An exhaust port 13 is provided through which the combustion exhaust gas that has passed through the exhaust port 11 flows out. Furthermore, an exhaust pipe 3 into which combustion exhaust gas flows through an exhaust port 13 is attached to the front plate portion 1b.

Referring also to FIG. 4, the mounting structure of the exhaust pipe 3 will be specifically described. In this embodiment, in order to attach the exhaust pipe 3, a mounting plate 4 having an opening 41 that matches the exhaust port 13 is provided. Then, the mounting plate 4 is stacked on the front surface of the front plate portion 1b with the packing 42 sandwiched therebetween, and the flange portion 34 at the rear end of the exhaust pipe 3 is stacked on the front surface of the mounting plate 4 with the packing 43 sandwiched therebetween. In this state, the flange portion 34 is fastened together with the packing 43, the mounting plate 4, and the packing 42 to the front plate portion 1b with screws 44. Further, the upper edge of the opening 41 of the mounting plate 4 is fastened to the front plate portion 1b together with the packing 42 using screws 45, and furthermore, the upper portion of the flange portion 34 is fastened to the mounting plate 4 together with the packing 43 using screws 46.

In this embodiment, in the heat exchange chamber 11, six heat absorption pipes 2 are arranged in the upper and lower directions, extending in the front-back direction while meandering in the lateral direction orthogonal to the front-back direction. The vertically adjacent endothermic pipes 2, 2 are shifted in position by half of the meandering pitch in the front-rear direction. An inflow header 21 and an outflow header 22 to which the upstream ends and downstream ends of the six endothermic pipes 2 are connected, respectively, are attached to the outer surface of the side plate 1c on one side in the lateral direction of the housing 1. Water flowing through each endothermic pipe 2 from the inflow header 21 to the outflow header 22 is heated by recovery of latent heat due to condensation of moisture in the combustion exhaust gas on the outer surface of each endothermic pipe 2.

A bottom surface 111 of the heat exchange chamber 11 constituted by the bottom plate of the housing 1 is inclined downward toward the front. At the front end of the bottom surface 111, a downwardly recessed drain receiving section 112 is provided, into which drain water dripping from the outer surface of the heat absorption pipe 2 flows due to the slope of the bottom surface 111. Referring to FIG. 3, the drain receiving part 112 has the lowest horizontal part that almost matches the exhaust port 13, and a drain port 113 for draining the drain water in the drain receiving part 112 is provided in this part. It is being Drain water drained from the drain port 113 is led to a neutralizer (not shown).

A cover plate 5 is provided at the lower front end portion of the heat exchange chamber 11 to cover a portion of the drain receiving portion 112 near the exhaust port 13 from above. The cover plate 5 can prevent the combustion exhaust gas from vigorously hitting the drain water in the drain receiving part 112 and being rolled up by the combustion exhaust gas. As clearly shown in FIG. 3, the cover plate 5 is sloped downward to one side in the lateral direction (to the right in FIG. 3). Therefore, the drain water on the cover plate 5 falls from one lateral end of the cover plate 5 to the drain receiving part 112.

A guide plate 6 is provided at the upper part of the front end of the heat exchange chamber 11 to guide the flow of combustion exhaust gas downward. The guide plate 6 prevents the combustion exhaust gas from going straight into the exhaust pipe 3 while containing splashes of drain water. The guide plate 6 hangs from a rear part 61 of the guide plate 6, which is fixed to the upper plate 1d of the housing 1 and forms the upper surface of the front end of the heat exchange chamber 11, and guides the combustion exhaust gas downward. It has a plate part 62 and an inclined plate part 63 that extends forward from the lower end of the hanging plate part 62 in an upwardly inclined manner.

Inside the exhaust pipe 3, there are a first rectifying member 31 at the top, a second rectifying member 32 below the first rectifying member 31, and a third rectifying member 33 below the second rectifying member 32. is provided. A first exhaust flow path 3a through which the combustion exhaust gas flows is defined between the first and second rectifying members 31 and 32, and a first exhaust flow path 3a is defined between the second and third rectifying members 32 and 33. A second exhaust flow path 3b is defined below the exhaust flow path 3a. Note that it is also possible to provide only the first and second rectifying members 31 and 32 in the exhaust pipe 3 so that the combustion exhaust gas flows only into the first exhaust flow path 3a. However, in this case, if the cross-sectional area of the first exhaust flow path 3a is narrowed, the pressure loss in the exhaust pipe 3 will increase. On the other hand, if two exhaust channels 3a and 3b, the first and second exhaust channels, are provided as in this embodiment, even if the cross-sectional area of each of the first and second exhaust channels 3a, 3b is narrowed, the exhaust The pressure loss of the cylinder 3 as a whole can be suppressed to a small level. By narrowing the cross-sectional area of each exhaust flow path 3a, 3b, it is possible to obtain an exhaust sound damping effect, which is useful for noise suppression. Furthermore, the rear ends of the second and third flow regulating members 32 and 33 are rounded to suppress the generation of wind noise.

Incidentally, the combustion exhaust gas that has passed through the lower end of the hanging plate part 62 of the guide plate 6 flows in a direction that is inclined forward and upward along the inclined plate part 63. Therefore, in this embodiment, the first exhaust flow path 3a is configured such that the rear portion 3ar is inclined upward toward the front, and the front portion 3af is substantially horizontal. Note that the front end of the inclined plate portion 63 and the rear end of the upper surface of the first exhaust flow path 3 a are located at approximately the same height as the upper end of the exhaust port 13 .

According to this, the combustion exhaust gas flowing in a direction inclined forwardly upward along the inclined plate portion 63 of the guide plate 6 flows into the first exhaust flow path 3a without significantly changing the direction, and flows into the inlet portion of the exhaust stack 3. The pressure loss at Here, the combustion exhaust gas is discharged from the exhaust stack 3 in response to supply pressure from a combustion fan that supplies combustion air, which is provided in a heat source device incorporating the latent heat recovery type heat exchanger A. If the pressure drop at the inlet of the exhaust pipe 3 is reduced, the rotational speed of the combustion fan required to properly discharge the combustion exhaust gas is also reduced, and fan noise can be reduced. Furthermore, since the front portion of the first exhaust flow path 3a is substantially horizontal, the direction in which the combustion exhaust gas is discharged from the exhaust stack 3 is substantially horizontal. Therefore, it is possible to prevent combustion exhaust gas from hitting the roof of the eaves where the heat source device incorporating the latent heat recovery type heat exchanger A is installed.

In a portion below the guide plate 6, the combustion exhaust gas flows approximately horizontally toward the front. Therefore, the second exhaust flow path 3b is designed to be substantially horizontal from the front to the rear. According to this, the direction of the combustion exhaust gas flowing into the second exhaust flow path 3b becomes the same direction as the second exhaust flow path 3b, and pressure loss does not increase.

Further, the lower surface of the second exhaust flow path 3b, that is, the upper surface of the third flow regulating member 33, is located above the lower end of the exhaust port 13. According to this, it is possible to effectively suppress drain water from entering the second exhaust flow path 3b from the exhaust port 13. Note that the rear end of the third rectifying member 33 hangs down to the same height as the lower end of the exhaust port 13, and the combustion exhaust gas is directed from the exhaust port 13 into the space inside the exhaust pipe 3 below the third rectifying member 33. A closing plate portion 33a is curved to prevent the inflow of water.

Although the embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited thereto. For example, without providing the third straightening member 33, the exhaust pipe 3 is formed so that its bottom is located at the same height as the top surface of the third straightening member 33, and the bottom of the exhaust pipe 3 and the second straightening member A second exhaust flow path 3b may be defined between the member 32 and the member 32.

A... Latent heat recovery heat exchanger, 1... Housing, 1b... Front plate part, 11... Heat exchange chamber, 13... Exhaust port, 2... Endothermic pipe, 3... Exhaust stack, 3a... First exhaust flow path, 3ar...Rear part of the first exhaust flow path, 3af...Front part of the first exhaust flow path, 3b...Second exhaust flow path, 31...First rectification member, 32...Second flow rectification member, 6... Guide plate, 62... hanging plate part, 63... inclined plate part.

Claims (3)

Equipped with a housing with an internal heat exchange chamber through which combustion exhaust gas flows from rear to front, and multiple heat absorption pipes placed in the heat exchange chamber, the latent heat held by the combustion exhaust gas is recovered to heat the water flowing through the heat absorption pipes. A latent heat recovery type heat exchanger configured to
An exhaust pipe is attached to the front plate of the casing, through which combustion exhaust gas flows through an exhaust port opened in the front plate.
At the front end of the heat exchange chamber, there is a hanging plate part that hangs down from the top surface of the heat exchange chamber and guides the flow of combustion exhaust gas downward, and a hanging plate part that extends forward from the lower end of the hanging plate part at an upward slope. A guide plate having an inclined plate portion is provided,
A first exhaust system in which a first rectifying member and a second rectifying member below the first rectifying member are provided in the exhaust stack, and combustion exhaust gas flows between the first and second rectifying members. In those in which a flow path is defined,
The first exhaust flow path is a latent heat recovery type heat exchanger characterized in that the rear part is inclined upward toward the front and the front part is substantially horizontal. 2. The exhaust pipe according to claim 1, wherein a second exhaust flow path is defined in the exhaust pipe, the second exhaust flow path being located below the first exhaust flow path and extending substantially horizontally from the front to the rear. Latent heat recovery heat exchanger. 3. The latent heat recovery type heat exchanger according to claim 2, wherein a lower surface of the second exhaust flow path is located above a lower end of the exhaust port.

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