JP2515131B2 - Water heater - Google Patents

Description

[Technical Field] In the present invention, a heat transfer tube is disposed in a flow path of a combustion gas such as a gas instantaneous water heater, and water is flowed through the heat transfer tube to take out hot water. Regarding water heaters.

“Prior art and its problems” Conventional hot water heaters such as gas instantaneous water heaters have a burner body such as a diffusion burner disposed below the casing, and the inside of the casing serves as a combustion gas flow path. A plurality of main heat transfer tubes are provided so as to cross the gas flow path, and these main heat transfer tubes are connected by a connecting pipe outside the casing.However, the combustion flame is long and the burner body is used to prevent incomplete combustion. The space directly above is not equipped with a main heat transfer tube as a combustion space,
The main heat transfer tube is installed at a distance of about 120 mm or more from the burner body.

It is also known that a secondary heat transfer tube is wound around the outer wall of the casing on the side of the combustion space to cool the casing having a high temperature by the combustion gas, and heat is also recovered from the casing. With respect to the gas flow direction, the main heat transfer tube was provided downstream of the sub heat transfer tube, and it was far from space saving.

In recent years, there has been an ever-increasing demand for downsizing of such a water heater, and it has been desired to employ a high-load combustion technique such as a premixed burner body or to arrange a heat transfer tube in the above-mentioned combustion space. However, there is nothing to be seen about the arrangement structure of the main heat transfer tube and the sub heat transfer tube which is suitable for compactification.

"Object of the Invention" An object of the present invention is to provide a hot water supply device having an arrangement structure of a main heat transfer tube and a sub heat transfer tube that is suitable for compactification, and further to prevent the occurrence of drain in the casing as much as possible. To provide a hot water supply device.

"Structure of the Invention" A water heater according to the present invention comprises a rectangular tubular casing arranged vertically, a burner body arranged at one of the upper and lower ends of the casing, and a plurality of main casings arranged in the casing. In a hot water supply device including a heat transfer tube and a sub heat transfer tube arranged along the outer wall of the casing, the main heat transfer tube has a plurality of upper and lower stages, and the distance between the outer edge of the main heat transfer tube closest to the burner body and the burner body is small.
It is arranged to be 100 mm or less, is fixedly supported by the first facing wall of the casing, and is sequentially connected from the upper part to the lower part by a connecting pipe arranged outside the first facing wall. Are branched into two at one end and then gathered at the other end, one branch pipe being located only along one of the second opposing walls, and the other branch pipe being located only along the other of the second opposing walls. In contact with each other, the respective branch pipes are sequentially arranged from the upper part to the lower part, the upper end of the main heat transfer pipe and the upper end of the sub heat transfer pipe are connected, and either one of the lower end of the main heat transfer pipe and the lower end of the sub heat transfer pipe is connected. Is a water inlet, and the other is a hot water outlet.

[Operation] That is, according to the conventional technique, in order to wind the sub heat transfer tube, it is necessary to form a radius R having a large radius of curvature in the corner portion of the casing. Since it is provided only on the two opposing walls, the corner portion of the casing can be manufactured without such a restriction.

Then, the second opposing wall of the casing is cooled by the secondary heat transfer tube adjacent thereto, so that its overheating is prevented, while
The main heat transfer tube is fixedly supported on the first opposed wall of the casing, and the first opposed wall is also deheated via this main heat transfer tube, so that it is also not overheated.

Furthermore, the connecting pipe is arranged outside the first opposing wall,
Since the sub heat transfer pipe is arranged along the second opposing wall that does not overlap with the arrangement position of the connecting pipe, the main heat transfer pipe and the sub heat transfer pipe are at substantially the same position in the flow direction of the combustion gas, in other words, from the burner body. They can be placed at approximately the same distance. This is particularly convenient when the main heat transfer tube is arranged at a position corresponding to the combustion space in the prior art to achieve compactness.

In addition, in order to burn at high load, it is particularly remarkable when using a premixed burner body, but even when using other types of burner body, the air-fuel ratio is considerably over-air. Compared with the case of low load combustion, it approaches the theoretical air-fuel ratio. This leads to an increase in the water content in the combustion gas, and cooling of the casing in the secondary heat transfer tube tends to increase the amount of drain generated on the inner wall of the casing. In the present invention, however, the sub heat transfer tube having a large casing cooling effect is provided only on the second opposing wall, and the sub heat transfer tube is provided on the first opposing wall so as to be cooled only by the main heat transfer tube. Since it is not overcooled as a whole,
It is possible to prevent and prevent the occurrence of such a drain.

In the present invention, the plurality of main heat transfer tubes are arranged in multiple stages at different distances from the burner body, that is, vertically.
Further, the number of main heat transfer tubes at each stage may be one, or a plurality of main heat transfer tubes may be arranged in multiple rows at substantially equal distances from the burner body. In general, it is preferable that they are arranged in multiple stages and in multiple rows. Then, the main heat transfer tube closest to the burner body is separated from the outer edge (or the outer edge of the fin if the main heat transfer tube has fins) by a distance of 10
It is placed so that the length is 0 mm or less, preferably 60 mm or less.

In the present invention, the sub heat transfer tube is divided into two at one end and then assembled at the other end, and one branch tube is attached to only one of the second opposing walls and the other branch tube. Is adjacent to the other of the second opposing walls. As a result, the piping structure can be simplified and made compact.

Further, according to the present invention, the main heat transfer tube and the sub heat transfer tube are sequentially connected from the upper part to the lower part, the upper end of the main heat transfer tube and the upper end of the sub heat transfer tube are connected, and the lower end of the main heat transfer tube and the sub heat transfer tube are connected. One of the lower ends of the above is a water inlet, and the other is a hot water outlet. As a result, water can be easily drained from the lower ends of the main heat transfer pipe and the sub heat transfer pipe after use, and water in the heat transfer pipe can be prevented from freezing, for example, in a cold region. If the connecting portion between the main heat transfer tube and the sub heat transfer tube is located below, the water accumulated in that portion cannot be extracted.

"Embodiment of the Invention" FIG. 1, FIG. 2, FIG. 3 and FIG. 4 show an embodiment of the hot water supply device of the present invention.

This hot water supply device has a rectangular tubular casing 11 surrounded by four wall surfaces 11a, 11b, 11c, 11d and having an opening at the top and connected to an exhaust port (not shown). This casing 11
With the burner body 12 arranged at the lower end as a boundary, the lower side is a mixing chamber 13 and the upper side is a combustion gas flow path 14.

In order to enable high-load combustion, a large number of small flame holes penetrating the planar burner body 12 are formed, and a premixed gas of combustion gas and air is ejected from the small flame holes to generate a planar flame. To form. In addition, 15 is a fuel gas nozzle for supplying fuel gas, 16
Is a fan for supplying combustion air, and ignition means for flame formation is not shown.

Inside the casing 11, a plurality of pipes (three pipes, two pipes, and three pipes in this order from the bottom) are provided so as to cross the combustion gas flow passage 14.
The main heat transfer tubes 18 are arranged in parallel with each other (four tubes, two tubes, 10 tubes in total). Of these, the distance between the lower outer edge of the lowermost main heat transfer tube 18 and the upper surface of the burner body 12 is about 40 mm,
Space saving is achieved. Both ends of the main heat transfer tube 18 are fixedly supported by the opposing wall surfaces 11a and 11b of the casing 11, and as shown in FIG.
They are connected in a meandering manner to each other by a U-shaped connecting pipe 17 arranged on the outer side of 11b, and as a whole, one continuous flow path is sequentially connected from the lower stage to the upper stage in series.

Of the end portions of the main heat transfer tube 18, the one that forms one end portion of this continuous flow path at the lowest stage is the water introduction port 23 that is the fluid to be heated.

On the other hand, among the end portions of the main heat transfer tube 18, the one that forms the other end portion of this connection flow path at the uppermost stage is connected to the two sub heat transfer tubes 20a, 20b via the branch portion 19. There is. These sub heat transfer tubes 20a, 20b are arranged so as to circulate meanderingly and have a long length, and are circumscribed on opposite wall surfaces 11c, 11d of the casing 11, respectively. The wall surfaces 11c and 11d are wall surfaces that are substantially parallel to the traveling direction of the main heat transfer tube 18 and are not in contact with the main heat transfer tube 18. The two branched heat transfer tubes 20a and 20b are assembled again below the casing 11 via the assembly portion 21, and the end portion thereof serves as a hot water outlet 24.

Although not shown in detail in the figure, the main heat transfer tube 18 is
It may be a finless tube or a finned tube. In a preferred embodiment, for example, the lower two
The main heat transfer tubes 18 located below the casing 11, such as the main heat transfer tubes 18 in stages, are tubes without fins or with low fins having a fin height of 5 mm or less. Main heat transfer tube located above
18 is a tube with high fins or plate fins having a fin height higher than that of the lower main heat transfer tube 18.

In the combustion gas flow path 14 between the lower main heat transfer tube 18 and the upper main heat transfer tube 18, as shown by phantom lines in FIGS. 1 and 2,
The radiator 22 may be arranged. As the radiant body 22, those having air permeability are preferable, and particularly, a honeycomb plate made of ceramics or an inorganic fiber molded body having vent holes is preferable.

In the above structure, the water introduced from the water inlet 23 flows in the main heat transfer tube 18 from the lower side to the upper side, and in the process, the heat is received by the main heat transfer tube 18 that has become hot due to contact with the combustion gas. And raise the temperature. In this case, if the main heat transfer tube 18 is provided with fins, the contact area with the combustion gas can be widened, so that the heat transfer efficiency is improved. Further, if the radiator 22 is arranged, the main heat transfer tube 18 is irradiated with the radiant heat from the radiator 22, so that the heat transfer efficiency is further improved.

When the water thus heated reaches the upper end of the main heat transfer tube 18, it then flows to the sub heat transfer tubes 20a and 20b through the branch portion 19. Water also recovers heat from the wall surfaces 11c and 11d of the casing 11 with which the sub heat transfer tubes 20a and 20b are in contact. In this way, the water is further heated, then merges in the collecting portion 21, and is taken out from the hot water outlet 24 as hot water.

In such a heat exchange process, the opposite wall surfaces 11a and 11b of the casing 11 in which the ends of the main heat transfer tubes 18 are fixedly supported are
Although not affected by the cooling effect of the sub heat transfer tubes 20a, 20b, it is cooled by the water flowing in the main heat transfer tube 18 because it is in contact with the main heat transfer tube 18. Further, since the sub heat transfer tubes 20a and 20b are provided along the opposing wall surfaces 11c and 11d of the casing 11 which are not in contact with the main heat transfer tube 18, they are cooled by the water flowing through them. Therefore, overheating of the casing 11 is prevented, and thermal damage to the casing 11 itself and to the instruments arranged around the casing 11 are also prevented. The opposing wall surfaces 11a, 11b of the casing 11 are cooled only by the main heat transfer tubes 18, and the wall surfaces 11c, 11d are cooled only by the sub heat transfer tubes 20a, 20b, so that the four wall surfaces 11a, 11b, 11c, 11d are excessive. It is not cooled, and the amount of drain generated is suppressed.

In this hot water supply device, when draining water, the water inlet port 23 and the hot water outlet port 24 are both located at the bottom, and the connecting portion between the main heat transfer pipe 18 and the sub heat transfer pipes 20a, 20b is at the top. Since it is located, the water in the main heat transfer pipe 18
The water in the sub heat transfer tubes 20a, 20b flows out from the hot water outlet 24. Therefore, water can be drained easily.

It should be noted that in the above embodiment, the case where the flow direction of the combustion gas is from the lower side to the upper side is shown, but the combustion gas may flow from the upper side to the lower side.

[Advantages of the Invention] As described above, according to the present invention, when the heat transfer tube is arranged not only in the interior of the casing but also in contact with the outer wall of the casing, the heat transfer tube arranged in contact with the outer wall of the casing is Since the heat transfer tubes are arranged only on the opposite wall surfaces except the wall surfaces to which both ends of the heat transfer tubes are fixed, both heat transfer tubes can be installed inside and outside the casing at approximately the same distance from the burner body, saving space. In addition, the wall surface of the casing can be prevented from being overcooled, and the amount of drain generated can be minimized. Therefore, problems such as corrosion of the casing due to the drain and damage to the combustion means can be solved.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of the hot water supply apparatus of the present invention, FIG. 2 is a left side view of the hot water supply apparatus, FIG. 3 is a plan view of the hot water supply apparatus, and FIG. It is sectional drawing which shows the fixing structure of the casing wall surface and the main heat transfer tube in an apparatus. 11 is a casing, 11a, 11b, 11c and 11d are wall surfaces, 12 is a burner body, 13 is a mixing chamber, 14 is a combustion gas passage, 17 is a connecting pipe, 18
Is a main heat transfer tube, 19 is a branch section, 20a and 20b are sub heat transfer tubes, and 21 is a collecting section.

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Yoshihiro Sugano 3-114 Umeda, Kasukabe City, Saitama Prefecture (72) Inventor Daisuke Koshimizu 2-11-2 Kajigaya, Takatsu-ku, Kawasaki City, Kanagawa Prefecture (56) References 62-84258 (JP, A) Actual opening 51-21161 (JP, U) Actual opening 60-63744 (JP, U)

Claims (2)

(57) [Claims] 1. A rectangular tubular casing arranged vertically, a burner body arranged at one of upper and lower ends of the casing, a plurality of main heat transfer tubes arranged in the casing, and an outer wall of the casing. In a hot water supply device including a secondary heat transfer tube arranged alongside, the main heat transfer tubes are arranged in multiple stages vertically and the distance between the outer edge of the main heat transfer tube closest to the burner body and the burner body is 100 mm or less. And is fixedly supported by the first facing wall of the casing, and is sequentially connected from the upper part to the lower part by a connecting pipe arranged outside the first facing wall. And then gathered at the other end, one branch pipe adjoins only one of the second opposing walls, and the other branch pipe adjoins only the other of the second opposing walls. Are arranged in order from the upper part to the lower part. The top and are connected, water heater one of the lower end of the lower end and 従伝 heat pipe main heat transfer tubes without water inlet, the other one is characterized in that it forms a hot water outlet. 2. A water heater according to claim 1, wherein the burner body is a premixed burner body.