JPS6136137B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thin heat exchanger with a large aspect ratio that can respond to the trend toward thinner thickness in a heat exchanger in which the circulation inlet/outlet section forming the main body of an external bathtub is a vertical type. The aim is to improve the

In recent years, water heaters (including bathtubs) are moving from the traditional era of single-function bathtubs to the era of multifunctional water heaters and bathtubs. Furthermore, due to larger hot water supply and bath capacity and safety concerns, more and more equipment is being installed outdoors. On the other hand, there is a desire for equipment to save space. In other words, on the one hand, as water heaters and bathtubs become more complex, the size of the equipment increases and more installation space is required, while on the other hand, there is a desire for smaller and thinner equipment.

Heat exchangers for bathtubs play a central role in realizing space-saving composite equipment by making water heating equipment thinner. Below, we will discuss the classification based on the installation form and the classification based on the shape.

Bath pots can be roughly divided into outdoor type (CF or all-weather exhaust type) as shown in Figure 6 a, and type 7.
There is an indoor installation type (BF exhaust type) as shown in figure a. The relationship between this indoor/outdoor bathtub and the heat exchanger (particularly the circulation inlet/outlet section) will be described below.

1. All heat exchangers used for outdoor installations have vertical circulation inlets and outlets. In addition, most of the shapes are close to rectangular as shown in FIG. 6b.

2. Most heat exchangers used indoors have circulation inlets and outlets that are left and right and up and down. Moreover, the shape is a thin type with a large aspect ratio, as shown in FIG. 7b.

As described above, there are no thin heat exchangers with a vertical circulation inlet/outlet and a large aspect ratio that are installed outdoors.

This is because, in the heat exchangers 1 and 2, in order to realize a thin heat exchanger with a vertical circulation inlet/outlet and a large aspect ratio that can be installed outdoors, the following problems are faced.

1. When the aspect ratio increases with respect to the vertically vertical circulation inlet and outlet sections, the flow of hot water tends to stagnate at both left and right ends in the heating width direction, which tends to cause partial boiling and deteriorates the kettle noise performance.

2. Thermal efficiency is also similar to the case, with the flow rate of hot water tending to decrease gradually toward both left and right ends in the heating width direction. Therefore, the amount of heat transferred between the central portion and both left and right ends is likely to be distributed (the amount of heat transferred at both left and right ends is small), so that the total amount of heat transferred is likely to decrease and the thermal efficiency is also likely to decrease. (However, this does not apply if the heat transfer area is increased, but the design becomes extremely uneconomical.) For the above reasons, it is recommended to use a thin heat exchanger with a vertical circulation inlet/outlet and a large aspect ratio in an external bathtub. In order to achieve this, it is not enough to simply design proportionally the conventional products from the viewpoints of ``kettle noise performance'' and ``thermal efficiency,'' and a great deal of ingenuity is required.

To this end, it is important to consider the following points.

1. How to move the fluid flowing in from the circulation inlet to the heat exchange element in a low temperature state.

2. How to move the fluid in the heat exchange collection section to the circulation outlet section.

3. How to effectively utilize the thermal radiation of combustion gas.

In view of the above problems, the present invention has been developed by making the upper water capacity of one of the heat exchange collecting parts connected to one end of the heat exchange element, which has a circulation inlet part and an extended water can part at the lower part, larger than that of the extended water can part. The other end is connected to the other end of the heat exchange element, has a circulation outlet part, and has an extended water tank part at the lower part. A pressure relief chamber is provided in the heat exchange gathering part to reduce the increase in flow resistance due to the growth of bubbles within the heat exchange element. The structure and function will be described below.

As shown in FIGS. 1 to 3, numeral 1 denotes a heat exchange element, which is composed of fin pipes 2 and fins 3, and is arranged in plural pieces in the heating width direction. The inlet section 4 of the heat exchange element 1 communicates with a heat exchange gathering section 6 having a circulation inlet section 5, and the inlet section 4 and the circulation inlet section 5 are set at opposing positions and at an upper position. Furthermore, the outlet section 7 of the heat exchange element 1 communicates with a heat exchange collection section 9 having a circulation outlet section 8 , the outlet section 7 and the circulation outlet section 8
It is located on the same wall and is set at the bottom.

Reference numeral 10 denotes water can portions located at both ends of the heat exchange gathering portions 6 and 9 in the heating width direction. This water can part 10 is located outside the heat exchange element 1 and is configured to abut on the plurality of fins 3 at the upper part. Furthermore, the water capacity of the water can part 10 is smaller in the lower part than in the upper part.

The above structure forms a heat exchanger, and the flow path circuit from the circulation inlet to the circulation outlet via the heat exchange element is arranged in series in stages.

In the above basic configuration, the heat exchanger assembly section 6 is a water can section 6' extending below the circulation inlet section 5. Furthermore, the heat exchange gathering part 9 is also formed into a water can part 9' which extends below the position of the heat exchange element 1.

The water capacity of the extended water can part 9' is extremely small compared to the water capacity of the extended water can part 6'.

The extended water can portions 6', 9' and both end water can portions 10 constitute part or all of the combustion chamber 13.

Next, the top surface of the heat exchange gathering section 6 has no slope in the heating width direction, whereas the top surface of the heat exchange gathering section 9 has a slope of 1.
1 and 11', a slope is provided toward the circulation outlet section 8.

A plurality of burners 12 are provided.

In the above basic configuration, the heat exchange collecting section 6 has a water capacity larger than the water capacity of the lower extension water pipe section 6'. This portion expands from the inside of the heat exchange gathering portion 6 heated by the burner 12 toward the outside surface that is not heated.

Next, the heat exchange gathering section 9 is provided with a pressure relaxation chamber 14 near the outlet section 7 of the heat exchange element 1, and is also provided with a slope section 15 on the wall surface facing the circulation outlet section 8.
In terms of the water capacity of the heat exchange gathering section 9, the pressure relief chamber 14 has the largest capacity, the second is near the circulation outlet section 8, and the extended water can section 9' has the smallest capacity.

Further, in order to make the heat exchanger assembly part 9 as thin as possible, the vicinity of the circulation outlet part 8 of the heat exchange gathering part 9 is made to protrude a little toward the burner 12 side.

The flow and operation of hot water in the thin heat exchanger of the present invention, in which the circulation inlet and outlet sections are vertically vertical and have a large aspect ratio, will now be described.

The low-temperature hot water flowing in from the circulation inlet section 5 is distributed in the heating width direction within the heat exchange gathering section 6, and one side passes through the fin pipe section 2, which is the heat exchange element 1, and moves toward the circulation outlet section 8. The other low-temperature hot water passes through the water can portions 10 at both ends and moves toward the circulation outlet portion 8.

Due to heating by the burner 12, the low-temperature hot water flowing in from the inlet portion 4 of the heat exchange element 1 becomes high in temperature and moves to the heat exchange gathering portion 9 with a certain speed. Further, the water can portions at both ends also move toward the heat exchange gathering portion 9 with a certain speed.

At this time, the hot water near the outlet 7 of the heat exchange element 1 becomes hotter than the temperature at the inlet 4, and active convection occurs. As a phenomenon, small-diameter air bubbles are generated inside the fin pipe 2 of the heat exchange element 1 and convection occurs, but if the hot water becomes too hot, the amount of air bubbles generated increases and becomes large in diameter. Then, due to the generation of bubbles and the bursting of the bubbles, the convection becomes irregular and boils rapidly, and the inner upper surface of the fin pipe 2 is filled with bubbles, and the hot water violently convects toward the heat exchange gathering part 9. Therefore, the low-temperature hot water flows into the inlet section 4 of the heat exchange element 1 through the circulation inlet section 5, and the bubbles disappear at once.
Accompanying this phenomenon is a rattling noise. Under this situation, the above phenomenon will normally be repeated at intervals of 5 to 8 seconds.

Therefore, as shown in FIG. 4, although the temperature of the hot water in the circulation inlet 5 rises with the heating time, at least the temperature of the hot water in the circulation inlet 5 remains the same.
The key is to move it to In this respect, if the circulation inlet/outlet is a horizontally elongated thin heat exchanger with a vertical up-and-down type and a large aspect ratio, a temperature difference is likely to occur between the center and both ends of the circulation inlet/outlet. In this respect, the present invention makes the water capacity of the heat exchange gathering part 6 equipped with the circulation inlet part 5 larger than that of the lower extension pipe part 6', so that the temperature of the water at the inlet part 4 of the heat exchange element 1 and the circulation inlet part are increased. I was able to make the water temperatures in No. 5 almost the same. In other words, the water capacity may be set so that the temperature of the hot water at the circulation inlet section 5 and the temperature of the hot water at the inlet section 4 of the heat exchange element 1 are approximately equal.

In addition, the conditions for the circulation outlet section 8 of the heat exchange gathering section 9 are such that the convection at the center in the heating width direction becomes intense and obstructs the convection at both ends, making it easy for the above-mentioned partial boiling to occur near both ends. The gradient 1 toward the circulation outlet 8 is intended to promote convection of the
1 and 11' are provided. This also serves to reduce the number of air bubbles near both ends. Furthermore, at the outlet portion 7 of the heat exchange element 1, the diameter of the bubbles increases with the passage of heating time, resulting in intense convection.
At this time, a pressure relief chamber is provided to make it as difficult as possible for bubbles to collide with each other, and a slope is provided toward the circulation outlet 8 to eliminate stagnation of hot water.

For the reasons mentioned above, it is desirable to provide this slope section above the outlet section 7 of the heat exchange element 1.

As described above, by devising the heat exchange gathering parts 6 and 9, we have succeeded in realizing a heat exchanger in which the occurrence of the kettle noise phenomenon is reduced.

Next, let's talk about thermal efficiency.

The combustion chamber 13 is formed by the heat exchange element 1, the extended water can part 6' of the heat exchange gathering part 6, the extended water can part 9' of the heat exchange gathering part 9, and the water can parts 10 at both ends. It is capable of absorbing high-temperature gas radiation.

At this time, the water capacity of the extended water can part 9' is reduced to promote heat transfer, and the structure is such that the amount of heat transferred is added to that obtained by the upper heat exchange element 1.
Even in the case of 0, the lower water capacity is reduced in order to absorb high temperature gas radiation and promote heat transfer.

Regarding thermal efficiency, as the aspect ratio increases, the amount of heat transferred tends to be distributed between the center and both ends of the circulation inlet and outlet, and the amount of heat transferred at both ends is smaller than the center, so the total amount of heat transferred decreases and the thermal efficiency tends to decrease. However, by adopting the above configuration as in this embodiment, the amount of radiant heat transfer is increased, and a large amount of total heat transfer is obtained without reducing the amount of heat transfer at both ends, thereby improving thermal efficiency. . Furthermore, as mentioned above, there are fewer stagnation areas in the convection of hot water and the flow velocity at the circulation inlet is faster, which leads to improved thermal efficiency.

As shown in FIG. 4, the above-mentioned BF heat exchanger in which the circulation inlet/outlet section is vertically up and down (undeveloped product) is compared with the example. As is clear from this, the heating time is short and the kettle noise performance is poor in the case without any ingenuity.
It can be seen that the rattling performance of the hook of this example is improved.

Further, FIG. 5 shows the levels of thermal efficiency of the conventional product and the example. As is clear from the figure, the level of thermal efficiency and the level of thermal efficiency of the example are higher even under the same heat transfer area load.

4 and 5 are representative examples of experimental data.

As described above, the flow path from the circulation inlet to the circulation outlet is made into a stepwise series circuit, and the lower part of the heat exchange gathering part is an extended water can part, and water can parts are set at both ends. Moreover, by devising both heat exchange gathering parts near the heat exchange elements, we were able to realize a horizontally long thin heat exchanger with a vertically up-and-down circulation inlet and outlet, which has excellent kettle noise performance and thermal efficiency.

As described above, according to the configuration of the present invention, the following effects can be obtained.

(1) Since the upper water capacity of one heat exchange gathering section is larger than that of the extended water tank section, there is a temperature difference in the hot water at one end of the heat exchange element where the circulation inlet section and one heat exchange gathering section are connected. This can reduce the noise caused by the transfer of low-temperature water to the heat exchange element.

(2) Since a pressure relief chamber is provided in the other heat exchange assembly, even if bubbles grow and the pressure increases at the other end of the heat exchange element connected to the other heat exchange assembly, this will be relieved. This makes it difficult for local boiling to occur, which can increase the water temperature at which kettle noise occurs.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of a heat exchanger according to an embodiment of the present invention, Fig. 2 is an external sketch of the same as above, Fig. 3 is a front sectional view of the main part of the same as above, Fig. 4 is a kettle noise performance diagram as above,
Figure 5 is the same thermal efficiency performance diagram as above, Figure 6 a is an external sketch of an outdoor (CF or all-weather) bathtub, b is an external sketch of the heat exchanger used in the above, and Figure 7 a is indoor Figure b is a diagram of the external appearance of a fixed-type (BF type) bathtub, and b is a diagram of the external appearance of the heat exchanger used in the same. DESCRIPTION OF SYMBOLS 1...Heat exchange element, 2...Multiple fin pipes, 3...Multiple fins, 5...Circulation inlet part, 6...Heat exchange collecting part, 6'...Lower part of heat exchange collecting part Extension water can part, 8... Circulation outlet part, 9...
Heat exchange gathering part, 9'... Lower extension water can part of the heat exchange gathering part, 10... Water can parts at both ends, 11, 11'...
Gradient part, 13... Combustion chamber, 14... Pressure relaxation chamber,
15...Gradient section.

Claims (1)

[Scope of Claims] 1. A heat exchange element, one heat exchange gathering part connected to one end of the heat exchange element, having a circulation inlet part and an extended water can part at the bottom, and one heat exchange gathering part connected to one end of the heat exchange element, and having a circulation inlet part and an extended water can part at the bottom; The other heat exchange assembly part is connected to the other heat exchange assembly part and has a circulation outlet part and an extended water can part at the lower part to constitute a heat exchange body and form all or a part of the combustion chamber, and the one heat exchange assembly part A heat exchanger for a thin bathtub, wherein the water capacity of the upper part of the extension water tank part is larger than that of the extension water can part, and a pressure relief chamber is provided in the other heat exchange collecting part. 2. The heat exchanger for a thin bathtub according to claim 1, wherein one heat exchange gathering portion is expanded to the non-heating side. 3. The heat exchanger for a thin bathtub according to claim 1, wherein the other heat exchange gathering part has a sloped part above the outlet part of the heat exchange element.