JPH10103784A - Combustion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sufficient supply of hot water without increasing an entire water flow resistance even when the diameter of the water pipe of an auxiliary heat exchanger is made small by dividing water flow into the auxiliary heat exchanger and a main heat exchanger and joining again hot water heated in the auxiliary heat exchanger to supply water before reaching the main heat exchanger. SOLUTION: Supply water is branched from a water supply pipe and supplied to water pipes 3 and water pipes 5. The supply water entering the water pipes 5 is heated by an auxiliary heat exchanger 4. Then, the heated supply water is joined to water to be supplied to a main heat exchanger 2 in the downstream side of the branch part of the water supply pipe and in the upstream side of the main heat exchanger 2. The supply water is heated in the main heat exchanger 2 and then the heated water is supplied from a hot water supply pipe. While the supply water supplied to the water pipes 3 and the water pipes 5 is heated by high temperature exhaust gas in the main heat exchanger 2, it is heated by exhaust gas performing a heating operation in the main heat exchanger 2, that is, by using exhaust heat in the auxiliary heat exchanger 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion apparatus such as a water heater, and more particularly, to a combustion apparatus in which latent heat of combustion gas is used to improve thermal efficiency.

[0002]

2. Description of the Related Art Conventionally, there has been a method of utilizing the latent heat of a combustion gas to improve the heat efficiency of a heat exchanger. Two heat exchangers are provided upstream and downstream of the combustion gas flow path, and water is passed in series from the downstream auxiliary heat exchanger to the upstream main heat exchanger.

[0003]

However, if water is passed in series to the two heat exchangers as in the prior art described above, the size of the auxiliary heat exchanger can be reduced without lowering the thermal efficiency and the combustion apparatus can be reduced. In order to reduce the overall size, the diameter of the water tubes constituting the auxiliary heat exchanger is reduced, and the water tubes are densely arranged. For example, the water pipe diameter of the main heat exchanger is 20 mm, and the water tubes of the auxiliary heat exchanger are When the diameter is 10 mm, there is a problem that a sufficient tapping amount cannot be obtained because the water flow resistance increases due to the reduction in the diameter of the water pipe.

Accordingly, an object of the present invention is to solve the above-mentioned conventional problems and to provide a combustion apparatus capable of efficiently performing heat exchange and obtaining a sufficient amount of hot water even if the heat exchanger is made as small as possible. .

[0005]

According to one aspect of the present invention, there is provided a combustion apparatus including a main heat exchanger, an auxiliary heat exchanger, and a burner. A water supply pipe to the water supply pipe, and a branch pipe to an auxiliary heat exchanger is provided.The branch pipe passes through the auxiliary heat exchanger, and the end thereof is located downstream of the branch with the water supply pipe and upstream of the main heat exchanger. It is characterized by being connected to. Further, the combustion device according to claim 2 is a combustion device provided with a main heat exchanger, an auxiliary heat exchanger, and a burner, wherein at least the auxiliary water exchanger is not provided with a heated portion in a water supply pipe. Features.

[0006] In the combustion apparatus of the first aspect, the supply water is passed from the branched water inlet circuit to the main heat exchanger and the auxiliary heat exchanger. The hot water heated by the auxiliary heat exchanger exits the auxiliary heat exchanger, merges with the water supplied to the main heat exchanger, enters the main heat exchanger, is heated again, and is heated. Therefore, even if the diameter of the water pipe constituting the auxiliary heat exchanger is reduced, the overall water flow resistance does not increase. Further, in the combustion apparatus according to the second aspect, since the water supplied to the auxiliary heat exchanger is not heated until reaching the auxiliary heat exchanger, the water is passed through the auxiliary heat exchanger at a low temperature. The lower the passing water temperature, the greater the temperature difference from the combustion gas from the burner, and the more efficient the heat exchange.

[0007]

FIG. 1 is a side sectional view of a combustion apparatus showing a first embodiment of the present invention, and FIG. 2 is a side sectional view of a combustion apparatus showing a second embodiment of the present invention.

In FIG. 1, the combustion apparatus according to the first embodiment has a main heat exchanger 2 upstream of an exhaust gas flow path 7 above a burner 1 and an auxiliary heat exchanger 4 downstream of a drain receiver 6. It is arranged in. Water tube 5 constituting auxiliary heat exchanger 4
Is smaller than the diameter of the water tube 3 constituting the main heat exchanger 2, for example, the diameter of the water tube 3 is 20 mm, the diameter of the water tube 5 is 10 mm, and the auxiliary heat exchanger 4 is compact by disposing the water tubes 5 densely. Can be The supply water is branched from a water supply pipe (not shown), and flows through the water pipes 3 and 5. After the supply water entering the water pipe 5 is heated by the auxiliary heat exchanger 4, on the downstream side of the branch of the water supply pipe and upstream of the main heat exchanger 2,
After joining with the water supplied to the main heat exchanger 2 and being heated by the main heat exchanger 2, the hot water is discharged from a hot water supply pipe (not shown). The supply water passed through the water pipe 3 and the water pipe 5 is heated by the high-temperature exhaust gas in the main heat exchanger 2, while the auxiliary heat exchanger 4 is heated by the main heat exchanger 2. , That is, using the exhaust heat.

In FIG. 2, the combustion apparatus according to the second embodiment has a main heat exchanger 2 upstream of an exhaust gas flow path 7 above a burner 1 and an auxiliary heat exchanger 4 downstream of a drain receiver 6. It is arranged in. Water tube 5 constituting auxiliary heat exchanger 4
Is smaller than the diameter of the water pipe 3 constituting the main heat exchanger 2, for example, the diameter of the water pipe 3 is 20 mm and the diameter of the water pipe 5 is 10 mm. 4
Can be reduced in size. The supply water branches at the branch of the water supply pipe, one of which is passed through the water pipe 5 of the auxiliary heat exchanger 4 without being heated, and the other of which is supplied to the water pipe 10 which is swirled around the outer wall 9 of the exhaust gas passage. Water is passed, and the two join again again downstream of the branch of the water supply pipe and upstream of the main heat exchanger 2 to reach the water pipe 3 of the main heat exchanger 2. The supply water passed through the water pipe 3 and the water pipe 5 is heated by the high-temperature exhaust gas in the main heat exchanger 2, while the auxiliary heat exchanger 4 is heated by the main heat exchanger 2. By
That is, the hot water is heated by using the exhaust heat and is discharged from a hot water supply pipe (not shown). The outer wall 9 of the exhaust gas passage heated by the high-temperature combustion gas is provided around the water pipe 1 which is swirled around it.
It is cooled by the supply water that has been passed through to zero. In other words, the supply water branched from the water supply pipe and passed through the water pipe 10 is heated before being supplied to the main heat exchanger 2, but is supplied before being supplied to the auxiliary heat exchanger 4 The water is not heated at all.

When water is heated using the exhaust heat in the auxiliary heat exchanger 4, the water in the exhaust gas is condensed to generate drain. This drain is strongly acidic, and if drained as it is, the drainage channels and structures may be corroded.
After being collected by the drain receiver 6, it is neutralized by the neutralizer 8.

The amount of water passing is arbitrary in both the first and second embodiments. For example, hot water heated by the auxiliary heat exchanger 4 is passed through the water pipe 3 and the water pipe 5 at a ratio of 8: 2. Water before being supplied to the exchanger 2 is merged, heated by the main heat exchanger 2 and then discharged from a hot water supply pipe (not shown). Therefore, even if the water pipe 5 constituting the auxiliary heat exchanger 4 is reduced in diameter. There is no increase in water flow resistance as a whole.

Further, since the amount of water passing through the main heat exchanger 2 is not different from the conventional case, the heat efficiency of the main heat exchanger 2 does not decrease.

[0013]

With the above-described configuration, the combustion apparatus of the present invention has the following effects. That is, in the combustion device of the first aspect, while branching and passing water to the auxiliary heat exchanger and the main heat exchanger, the hot water heated in the auxiliary heat exchanger is again joined with the supply water before reaching the main heat exchanger. By doing so, even if the diameter of the water pipe constituting the auxiliary heat exchanger is reduced, the overall water flow resistance does not increase, so that a sufficient amount of hot water can be obtained. Therefore, by arranging the water pipes with smaller diameters more densely, it is possible to reduce the size of the auxiliary heat exchanger, and the flow rate of water in the main heat exchanger is the same as before and the thermal efficiency does not decrease. There is no need to increase the size of the exchanger. As a result, the size of the entire combustion apparatus can be reduced. Further, in the combustion device according to the second aspect, since the supply water is supplied to the auxiliary heat exchanger at a low temperature without receiving any heating action, the heat efficiency of the auxiliary heat exchanger can be improved. There is an effect that the heat exchanger can be reduced in size, and the entire combustion device can be reduced in size.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a combustion device showing a first embodiment of the present invention.

FIG. 2 is a side sectional view of a combustion apparatus showing a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Burner 2 Main heat exchanger 3 Water pipe 4 Auxiliary heat exchanger 5 Water pipe 6 Drain receiver 7 Exhaust gas flow path 8 Neutralization device 9 Outer wall of exhaust gas flow path 10 Water pipe

Continued on the front page (72) Inventor Hidenori Hata 93, Edo-cho, Chuo-ku, Kobe-shi, Hyogo Pref. (72) Inventor Itsuo Nagai 93, Edo-cho, Chuo-ku, Kobe, Hyogo (72) ) Inventor, Ryoji Kutsuna 93, Edocho, Chuo-ku, Kobe, Hyogo Pref. (72) Inventor Takahiro Matsuda 93, Edocho, Chuo-ku, Kobe, Hyogo Pref.

Claims (2)

[Claims] 1. A combustion device comprising a main heat exchanger, an auxiliary heat exchanger, and a burner, wherein a branch pipe for branching a water supply pipe to the main heat exchanger and leading to the auxiliary heat exchanger is provided. A combustion apparatus, wherein the branch pipe is connected via an auxiliary heat exchanger to a terminal downstream of a branch with the water supply pipe and upstream of a main heat exchanger. 2. A combustion device comprising a main heat exchanger, an auxiliary heat exchanger, and a burner, wherein at least a part to be heated is not provided in a water supply pipe up to the auxiliary heat exchanger. Burning device.