JP2004163059A - Heat exchanger for hot water supply - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger for hot water supply for improving heat efficiency and durability of the heat exchanger (improving dew formation preventing performance and preventing retention of occurring moisture condensed water). <P>SOLUTION: The heat exchanger has a plurality of tiltingly arranged plate-like fins 1. The plate-like fins 1 are provided with a plurality of heat transfer pipes 2 horizontally and vertically tilted with respect to the passing direction of combustion gas, and with a guide plate 10 for changing flow direction of the combustion gas. The heat exchanger has projections 11 for surrounding the upstream side with respect to the passing direction of combustion gas of the heat transfer pipe (upper heat transfer pipe) on the downstream side of the passing direction of combustion gas of the heat transfer pipe, and a notch holes 12 near the heat transfer pipes. The projections are formed by cutting and folding the plate-like fins 1. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hot water supply heat exchanger.
[0002]
[Prior art]
FIG. 9 shows a conventional heat exchanger of this type. The hot water supply device uses a gas or gasified kerosene as fuel, burns a burner with a gas mixed with air sent by a fan, and is provided with a heat exchanger that forms a combustion chamber above the burner. The heat exchanger is composed of plate-like fins 1 vertically arranged at regular intervals and a heat transfer tube 2 inserted vertically into the plate-like fins 1. The combustion gas 5 heated by the burner flows and exchanges heat with water in the heat transfer tube 2. When the temperature of the water after the heat exchange is low, dew condensation easily occurs. 1. Adhesion stays at 1. Therefore, it was necessary to perform complicated control such as changing the rotation speed of the fan delicately in accordance with the required amount of heat of the burner. Further, the heat not absorbed at this time is exhausted from the exhaust port at a high temperature as exhaust gas (for example, see Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2000-274673
[Problems to be solved by the invention]
However, in the above-described conventional hot water supply apparatus equipped with this type of heat exchanger, the control of the fan is complicated and the development takes time, and the combustion gas 5 slips through the heat transfer tubes 2 as shown in FIG. Since the water passes through as it is and is discharged from the exhaust port of the hot water supply device, there is a problem that the thermal efficiency is reduced.
[0005]
Even if the complicated fan control is performed, the combustion gas 5 contains moisture generated by combustion as steam, and when the combustion is performed at a low excess air rate or when the combustion amount is reduced, It was inevitable that the combustion gas would be cooled by the heat exchanger to become saturated steam, and would be condensed on the low-temperature fins and land on it. The condensed water is highly acidic water due to CO2 and NOx in the combustion gas, and promotes oxidation of copper fins, and the distance between the fins is shortened by the oxides, resulting in clogging between the fins and durability of the heat exchanger. Is significantly deteriorated, and incomplete combustion is induced to cause a failure of the water heater.
[0006]
Therefore, as a heat exchanger for hot water supply, of course, it is important to control the generation of dew condensation water by simple control, but it is important to improve the thermal efficiency with a configuration in which dew condensation water flows even if generated. Become.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a plurality of plate-like fins arranged side by side with a slant in the direction of the heat transfer tube, a plurality of the slanted heat transfer tubes connected to the plate-like fin, and the heat transfer tube. A cutout hole is provided in the vicinity of the plate-like fin. As a result, even if condensed water is generated, the condensed water flows through the cutout holes and flows along the slope, so that clogging between the fins can be prevented and deterioration of the durability of the heat exchanger and incomplete combustion can be prevented. it can.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
In order to solve the conventional problem, the invention according to claim 1 includes a plurality of plate-like fins arranged side by side with a slant in the heat transfer tube direction, and a plurality of the slanted plurality of the plate-like fins connected to the plate-like fin. By providing notched holes in the heat transfer tube and the plate-shaped fins near the heat transfer tube, even if dew condensation water is generated, the dew condensation water flows along the slope. Of the heat exchanger can be prevented from deteriorating the durability of the heat exchanger.
[0009]
In addition, the invention according to claim 2 is the invention according to claim 1, in which the plate-like fin has a guide plate for changing the flow direction of the combustion gas, so that the combustion gas is transferred to the heat transfer tube having the highest fin efficiency by the guide plate. Direction in the direction to improve thermal efficiency, or to conduct heat to low-temperature parts where dew condensation is likely to occur, can suppress the occurrence of dew condensation.However, if dew condensation water occurs, the dew condensation Since it flows, dew condensation water does not stay in the fins, so that oxidation of the copper fins can be prevented, and the durability of the heat exchanger can be prevented from deteriorating.
[0010]
According to a third aspect of the present invention, in the first and second aspects, a projection surrounding the upstream side with respect to a direction in which the combustion gas passes through the heat transfer tube has a protrusion, so that the heat transfer tube near the heat transfer tube having the highest fin efficiency is provided. Increases heat absorption by increasing heat absorption.
[0011]
In addition, since the fin temperature is increased to increase heat absorption, dew condensation can be prevented.However, when dew condensation water is generated, the dew condensation water flows by inclination through a hole provided at a lower portion of the heat transfer tube. Since the fins do not stay, oxidization of the copper fins can be prevented and the durability of the heat exchanger can be prevented from deteriorating.
[0012]
According to a fourth aspect of the present invention, in particular, in the third aspect, the plate-like fin has a heat transfer tube inclined at a plurality of stages with respect to a direction in which the combustion gas passes. First, since the heat of the combustion gas is absorbed by the heat transfer tube provided on the upstream side with respect to the flow of the combustion gas, the temperature of the combustion gas decreases, and the amount of heat absorbed by the heat transfer tube on the downstream side decreases.
[0013]
In addition, due to this, the fin temperature becomes lower toward the downstream of the flow of the combustion gas, so that dew condensation easily occurs.
[0014]
However, according to this method, the protrusion provided on the downstream side of the heat transfer tube can increase the amount of heat absorbed on the downstream side of the heat transfer tube, so that it is possible to further improve durability performance and thermal efficiency by preventing dew condensation. Even if the water is generated, the condensed water flows due to the inclination through the hole provided in the lower part of the heat transfer tube, so that the condensed water does not stay in the fins, so that the durability can be further improved.
[0015]
According to a fifth aspect of the present invention, in the third and fourth aspects, the projections are provided by cutting and raising plate-like fins, so that the processing is simple, and the heat absorbed by the projections due to the holes generated by cutting and raising is provided. , To the downstream heat transfer tube.
[0016]
Therefore, the amount of heat absorbed on the upstream side of the heat transfer tube decreases, and the amount of heat absorbed on the downstream side of the heat transfer tube increases, so that the temperature difference between the plate-shaped fins is reduced. The generation of cracks in the heat transfer tube and the like can be prevented.
[0017]
According to a sixth aspect of the present invention, in each of the second to fifth aspects, the height of the guide plate or the projection is set to the same distance as the interval between the plate-like fins, and the distance between the fins is accurately managed. Is what you do.
[0018]
Therefore, variations in the heat transfer performance of the heat exchanger can be reduced, and the tapping capacity of the equipment can be stabilized.
[0019]
【Example】
(Example 1)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1A is a side sectional view of a water heater incorporating a heat exchanger for hot water supply according to Embodiment 1 of the present invention. FIG. 1B is a front sectional view of the hot water supply heat exchanger according to the first embodiment of the present invention, and it can be seen that the plate-like fins 1 and the heat transfer tubes 2 are arranged with an inclination. 3 is a burner, 7 is a combustion chamber, and 6 is an exhaust port. At the heat exchanger 4, the plate-like fins 1 are provided at a certain interval with an inclination, and are surrounded by the body 9.
[0020]
Further, the heat transfer tube 2 is also provided with an inclination. FIG. 2 is a front view of the plate-like fin 1, and the plate-like fin 1 is provided with a cutout hole 12. In general, it has been found that dew condensation tends to occur on the downstream side (portion A) of the heat transfer tube where the heat transfer tube becomes resistant and the combustion gas 5 hardly flows, and the temperature tends to be low, and the notch hole 12 should be provided in this area. Good.
[0021]
As a result, even if condensed water is generated, the condensed water passes through the notch hole 12 and flows along the slope, so that the condensed water does not stay and clogging between the fins can be prevented, and the durability of the heat exchanger can be improved. Deterioration and incomplete combustion can be prevented.
[0022]
(Example 2)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a front view of the plate-like fin 1, and the difference between the second embodiment and the first embodiment is that the plate-like fin 1 is provided with a guide plate 10. Since the combustion gas 5 heated by the burner 3 is guided by the guide plate 10 to the vicinity of the heat transfer tube having the highest fin efficiency, the heat efficiency can be improved.
[0023]
As a result, if the heat exchangers 4 have the same size, the heat efficiency can be increased, the fuel can be reduced, the energy can be effectively used, CO2 can be reduced, and global warming can be prevented. In addition, if the same thermal efficiency is sufficient, the heat exchanger 4 can be made smaller to reduce the size and weight.
[0024]
The performance required of the heat exchanger for hot water supply together with the thermal efficiency has a durable performance, but dew condensation which occupies most of the durable performance will be described. In a water heater, the moisture generated by combustion is contained in the combustion gas as water vapor, and when the combustion is performed at a low excess air ratio or when the combustion amount is reduced, the combustion gas is cooled by the heat exchanger. It becomes saturated water vapor and adheres to the downstream part of the fin, which is low temperature, as dew condensation water.
[0025]
This condensed water becomes highly acidic water due to CO2 and NOx in the combustion gas, promotes oxidation of copper fins, and the distance between the fins is shortened due to the accumulation of oxides, and the fins are clogged. This significantly deteriorates durability and induces incomplete combustion, which causes a failure of the water heater.
[0026]
Therefore, it is, of course, necessary to suppress the generation of dew water as much as possible, but it is necessary to have a configuration in which even if the dew water is generated, it does not stay in the fins and flows down from the fins. The guide plate 10 guides the high-temperature combustion gas 5 to the downstream side (part A) of the heat transfer tube, where the heat transfer tube becomes a resistance and the flow of the combustion gas 5 becomes difficult, and the temperature tends to be low. Although the generation of the condensed water can be prevented to some extent, even if the condensed water is generated by the provided notch holes 12, the condensed water passes through the notch holes 12 and flows along the slope. Further, deterioration of durability of the heat exchanger and incomplete combustion can be prevented.
[0027]
(Example 3)
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 4A is a front view of the plate-like fin 1, and FIG. 4B is a side sectional view. The third embodiment differs from the first and second embodiments in that a semicircular projection 11 is provided to surround the upstream with respect to the direction in which the combustion gas 5 passes, and a notch hole 12 is provided near the projection 11. is there.
[0028]
In this configuration, the semi-circular projection 11 acts as a resistance to the flow of the combustion gas 5, and the high-temperature combustion gas 5 heated by the burner 3 hits the projection 11. From the heat transfer tube.
[0029]
Further, the fin area around the heat transfer tube having high fin efficiency is increased by the protrusion 11. From these, the thermal efficiency can be improved. In addition, the generated dew water is once received by the projections 11 so that the dew water can be received in a wide range.
[0030]
Since the plate-like fins 1 and the heat transfer tubes 2 are arranged at an angle, they flow through the notch holes 12, so that the durability of the heat exchanger and the incomplete combustion can be further prevented.
[0031]
(Example 4)
Next, a fourth embodiment of the present invention will be described with reference to FIG. The fourth embodiment differs from the first, second and third embodiments in that the plate-like fin 1 is provided with a plurality of stages of heat transfer tubes 2a and 2b in the vertical direction with respect to the direction in which the combustion gas passes. In FIG. 3, two stages are provided as an example), and a semicircular projection 11 surrounding the heat transfer tube is provided only on the downstream side (heat transfer tube 2b) with respect to the direction in which the combustion gas 5 passes.
[0032]
FIG. 6 shows the temperature distribution of the plate-like fins. As shown in FIG. 6, in the conventional plate-like fin, as the height position H of the plate-like fin 1 shown in FIG. 9 increases, the temperature decreases (as it goes downstream with respect to the flow direction of the combustion gas 5). In particular, when a plurality of heat transfer tubes are provided, the amount of dew condensation increases, and the temperature difference depending on the height position H is large. That is, this means that the heat of the high-temperature combustion gas 5 heated by the burner 3 is first taken away by the heat transfer tube lower stage 2a, and after the temperature of the combustion gas 5 is lowered, heat is exchanged by the heat transfer tube upper stage 2b. This means that the heat transfer tube upper stage 2b has a lower heat absorption ratio. According to the configuration shown in the fourth embodiment, heat absorption can be improved only on the upper stage side by the projections 11 provided on the upper stage 2b of the heat transfer tube.
[0033]
That is, the upper-stage projection 11 becomes a resistance of the flow of the combustion gas 5 and receives the heat of the combustion gas. Then, the fin area around the heat transfer tube with high fin efficiency is increased by the protrusion 11. Therefore, the fin temperature on the downstream side at the height position H becomes higher, so that dew condensation is prevented, and the heat efficiency is further improved by providing the heat transfer tubes in a plurality of stages.
[0034]
In addition, the generated dew water is once received by the projections 11 so that the dew water can be received in a wide range. Since the plate-like fins 1 and the heat transfer tubes 2 are arranged with an inclination, they flow through the notch holes 12, so that further deterioration of the durability of the heat exchanger and incomplete combustion can be prevented.
[0035]
(Example 5)
Next, a fifth embodiment of the present invention will be described with reference to FIG. The difference between the fifth embodiment and the fourth embodiment is that a cut-and-raised hole 14 is provided by providing the protrusion 11 by cutting and raising the plate-like fin 1. The heat held by the plate-like fin 1 was transmitted to both the lower heat transfer tube stage 2a and the upper heat transfer tube stage 2b and exchanged heat. However, the protrusion 11 was received by the cut-and-raised hole 14 generated by providing the protrusion 11 by cutting and raising. Most of the heat is transmitted to the heat transfer tube upper stage 2b and heat exchange is performed (the heat is not transmitted to the heat transfer tube lower stage 2a side due to the cut-and-raised holes 14).
[0036]
Therefore, the amount of heat flowing to and absorbed by the heat transfer tube lower stage 2a decreases, and the amount of heat flowing and absorbed by the heat transfer tube upper stage 2b increases, so that the temperature difference due to the plate-like fin height H decreases as shown in FIG. In addition, it is possible to prevent cracks in the heat transfer tube or the like due to thermal stress generated due to a temperature difference, and further prevent the occurrence of dew condensation. However, when dew condensation occurs, the plate-like fin 1 and the heat transfer tube 2 are arranged with an inclination. Therefore, since the heat flows through the notch hole 12, the durability of the heat exchanger and the incomplete combustion can be further prevented.
[0037]
(Example 6)
Next, a sixth embodiment of the present invention will be described with reference to FIG. The difference between the sixth embodiment and the fifth embodiment is that the height of the guide plate 10 and the protrusion 11 is the same as the distance 13 between the plate-like fins 1. Conventionally, an inter-fin distance fixing jig was required when fins were arranged. However, in the present invention, the inter-fin distance can be accurately controlled only by superposing the plate-like fins 1 and assembling them, and the combustion gas 5 is transferred to each plate-like fin. Since the heat can be supplied uniformly between the heat exchangers, variations in the heat transfer performance of the heat exchanger 4 can be reduced, and the tapping capacity of the equipment can be stabilized.
[0038]
【The invention's effect】
As is clear from the above description, the following effects can be obtained according to the hot water supply heat exchanger of the present invention. In other words, in the thermal efficiency and the dew condensation performance that affect the performance of the hot water supply heat exchanger, a configuration is adopted in which the dew condensation is suppressed while improving the thermal efficiency, and even when the dew condensation occurs, it flows without stagnating between the fins. Accordingly, if the heat exchangers have the same size, the heat efficiency can be increased, the fuel can be reduced, the energy can be effectively used, CO2 can be reduced, and global warming can be prevented.
[0039]
In addition, if the same thermal efficiency is sufficient, the heat exchanger can be made smaller to reduce the size and weight.
[0040]
In addition, since the condensed water is generated as much as possible and the generated condensed water flows, the heat exchanger is used to prevent oxidation of the copper fins due to the condensed water and to prevent blockage between the fins due to the accumulation of this oxide. And the safety can be improved.
[Brief description of the drawings]
FIG. 1A is a configuration diagram of a hot water supply apparatus incorporating a hot water supply heat exchanger according to a first embodiment of the present invention. FIG. 1B is a sectional side view of a plate-like fin according to the first embodiment of the present invention. 2 is a front view of a plate fin according to the first embodiment of the present invention. FIG. 3 is a front view of a plate fin according to a second embodiment of the present invention. FIG. 4A is a third embodiment of the present invention. FIG. 6B is a front view of the plate-shaped fin in the third embodiment of the present invention. FIG. 5B is a front view of the plate-shaped fin in the fourth embodiment of the present invention. FIG. 7 is a front view of a plate fin according to a fifth embodiment of the present invention. FIG. 8 is a side view of the plate fin according to a sixth embodiment of the present invention. Front view of plate fin
DESCRIPTION OF SYMBOLS 1 Plate-shaped fin 2 Heat transfer tube 2a Heat transfer tube lower stage heat transfer tube 2b Heat transfer tube upper stage multiple stage heat transfer tube 4 Heat exchanger 10 Guide plate 11 Projection 12 Notch hole 13 Fin spacing 15 Guide plate height 16 Projection height

Claims (6)

A plurality of plate-like fins arranged side by side with an inclination in the direction of the heat transfer tube, a plurality of the heat transfer tubes with an inclination connected to the plate-like fin, and a notch hole in the plate-like fin near the heat transfer tube. Heat exchanger for hot water supply provided. The heat exchanger for a water heater according to claim 1, wherein the plate-like fin is provided with a guide plate for changing a flow direction of the combustion gas. The hot water supply heat exchanger according to claim 1 or 2, further comprising a projection surrounding an upstream side of the heat transfer tube with respect to a direction in which the combustion gas passes. 4. The hot water supply heat exchanger according to claim 3, wherein the plate-like fins have heat transfer tubes inclined at a plurality of stages with respect to the direction of passage of the combustion gas. The hot water supply heat exchanger according to claim 3, wherein the projection is provided by cutting and raising a plate-like fin. The hot water supply heat exchanger according to any one of claims 2 to 5, wherein the height of the guide plate and the projection is set to be equal to the distance between the plate-like fins.

Images