JPH07146003A - Gas combustion device - Google Patents

Abstract

PURPOSE:To allow combustion exhaust air in proportion to the level of condensation rate to flow in and condense the combustion exhaust air with high efficiency and enhance heat absorption efficiency of latent heat by lowering the flow rate of combustion exhaust air from the upstream side to the downstream side at a sub-heat exchanger unit which absorbs the latent heat of the combustion air. CONSTITUTION:A gas burner, a main heat exchanger unit and a sub-heat exchanger unit 1b are installed in order inside a drum body 6. As the gas burner is burnt, heated water flows in from the sub-heat exchanger and flows out to the main heat exchanger, the sensible heat of combustion air is absorbed at the main heat exchanger during this operation. The latent heat of combustion exhaust air is absorbed at the sub-heat exchanger unit 1b. Under the construction described above, a distribution plate 5 is installed to the downstream side of the main exchanger unit so as to set a flow rate of combustion exhaust air to the sub-heat exchanger unit 1b. More specifically, a large number of penetration holes 50 are installed in a required density distribution so as to drop the flow rate of combustion exhaust air to be supplied to each of water flow lines (a) to (c) to the sub-heat exchanger unit 1b step by step or continuously from the upstream side to the downstream side.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a gas combustion device, in particular
The present invention relates to a gas combustion apparatus of a type that condenses water vapor in combustion exhaust gas of a gas burner and absorbs latent heat of the water vapor in a heat exchange section to improve thermal efficiency.

[0002]

2. Description of the Related Art As a gas combustor of the type described above, there is one in which a gas burner (3) and a two-stage heat exchanger (1) are combined, as shown in FIG. The heat exchanger (1) is composed of a water pipe (11), a large number of fins (12) (12) provided on the outer periphery of the water pipe (11), and a can body (6) accommodating them. The vessel (1) is divided into a main heat exchange part (1a) on the downstream side of the water pipe (11) and an auxiliary heat exchange part (1b) on the upstream side of the water pipe (11) arranged below it. . The main heat exchange section (1a)
The water passage pipe (11) on the side is formed so that the water passage pipe (11) in the portion is meandered so that the water passage pipe (11) has a three-stage configuration. 11) is in a state of meandering in two or three rows. The water pipe (11) on the side of the sub heat exchange section (1b) is formed in a meandering shape in three horizontal rows.

The flame hole portion of the gas burner (3) is set downward, and the main heat exchange portion (1a) is arranged near the flame forming region. And the gas burner
In (3), the combustion air is forced to be supplied by the fan (4), so that the combustion exhaust of the gas burner passes through the main and auxiliary heat exchange sections (1a) and (1b). ,
It is adapted to be discharged to the outside through an exhaust passage (21) below this.

In this case, when the gas burner (3) is burned and tap water is supplied from the upstream end of the water pipe (11) of the sub heat exchange section (1b), the combustion exhaust of the gas burner (3) is changed to the fan (4). ) Supplies the heat to the main heat exchange section (1a) and the sub heat exchange section (1b), and the heat is absorbed by the water passing through these heat exchange sections.
From the downstream end of the water pipe (11) in (1a) is taken out as hot water, but in the endothermic action, the main heat exchange part (1a)
The main function is to absorb the sensible heat of the combustion exhaust of the gas burner (3), and in the auxiliary heat exchange section (1b), the steam in the combustion exhaust of the gas burner (3) is mainly condensed to generate its latent heat. The action of absorbing heat is performed. That is, the sub heat exchange section
In (1b), the sensible heat is taken away in the main heat exchange section (1a) to cool the combustion exhaust gas cooled below its dew-point temperature to generate drainage, and the latent heat at that time is generated to the sub-heat exchange section (1b). The water inside the water pipe (11) is made to absorb heat. In this case, not only the sensible heat in the combustion exhaust gas but also the latent heat is positively absorbed in the heat exchange section, so that there is an advantage that the thermal efficiency is improved.

However, this one cannot sufficiently improve the thermal efficiency. Since the sensible heat of the combustion exhaust gas from the gas burner (3) is taken by the main heat exchange section (1a), the exhaust temperature when it reaches the sub heat exchange section (1b) is the main heat exchange section (1a). Lower than that. In addition, the sub heat exchange part (1
Since water is supplied from the water pipe (11) on the b) side, the water pipe (1)
In 1), the part located upstream is at a lower temperature than the part located downstream. For these reasons, the efficiency (condensation rate) of cooling the combustion exhaust below the dew point is highest on the upstream side of the water pipe (11). However, with this one,
The flow distribution of the combustion exhaust gas of the gas burner (3) supplied by the fan (4) is substantially uniform over the entire traveling range of the water pipe (11) in the sub heat exchange section (1b). That is, the combustion exhaust gas having a substantially uniform flow rate is sent to the vicinity of the upstream end of the water pipe (11) having the highest condensation rate and its downstream side having a lower condensation rate than this. For this reason, it is not possible to efficiently condense the combustion exhaust gas and absorb the latent heat, and therefore the thermal efficiency cannot be sufficiently improved.

As shown in FIG. 16, the gas burner (3)
Even in the type in which the main heat exchange section (1a) is arranged above and the sub heat exchange section (1b) is arranged above the main heat exchange section (1a), When the combustion exhaust gas is condensed in 1b), the same inconvenience as described above occurs. The present invention is such a "main heat exchange section (1a) and a gas burner
The sub-heat exchange section (1b) provided on the downstream side of the exhaust flow from (3) is installed side by side in the can body (6), and the heated water in the water pipe that passes through these heat exchange sections is The main heat exchange part (1b) is introduced into the main heat exchange part (1a) side, and the main heat exchange part (1
It is an object of the present invention to improve the thermal efficiency of a gas combustion apparatus in which the sensible heat of the combustion exhaust gas is absorbed in a) and the latent heat is absorbed from the combustion exhaust gas in contact with the sensible heat of the auxiliary heat exchange section (1b).

[0007]

[Technical Means] The technical means of the present invention taken to solve the above-mentioned problem is that "a main flow of a flow rate distribution setting plate for setting a flow rate distribution of combustion exhaust gas to the auxiliary heat exchange section (1b) is exchanged. It is provided on the downstream side of the portion (1a), and the exhaust gas flow rate is reduced stepwise or continuously from the upstream side portion to the downstream side portion of the water pipe of the auxiliary heat exchange portion (1b). "

[0008]

The above technical means of the present invention operates as follows. When the gas burner (3) is burned and the heated water is supplied from the water pipe on the side of the sub heat exchange section (1b), the water in the main heat exchange section (1a) and the sub heat exchange section (1b) will flow through the gas burner ( It absorbs the amount of heat generated in (3), but in this endothermic action, the sensible heat of combustion exhaust is absorbed in the main heat exchange section (1a) and the sensible heat of the gas burner (3) is absorbed in the auxiliary heat exchange section (1b). Is condensed and its latent heat is absorbed.

At this time, a flow rate distribution setting plate is provided on the downstream side of the main heat exchange section (1a), and the flow rate distribution setting plate sends the flow rate distribution plate to the water pipe of the sub heat exchange section (1b). The exhaust gas flow rate is set to decrease stepwise or continuously from the upstream side portion to the downstream side portion of the water pipe. Also, the combustion exhaust from the gas burner (3) is the main heat exchange part.
Since the sensible heat is taken away in (1a), the exhaust temperature when the combustion exhaust reaches the sub heat exchange section (1b) is the main heat exchange section (1a).
Lower. On the other hand, water is supplied from the upstream end of the water pipe in the sub heat exchange part (1b), and the water in the water pipe is sub heat exchange part (1b).
Since heat is absorbed in the path from the side to the main heat exchange section (1a), the temperature of the water pipe is lowest at the upstream end and gradually increases toward the downstream side. Therefore, the efficiency (condensation rate) of cooling the combustion exhaust below the dew point is the highest at the upstream end of the water pipe, and the condensation rate becomes gradually lower as it goes downstream of the water pipe.

In the sub heat exchange section (1b), from the upstream side to the downstream side of the water pipe of the sub heat exchange section (1b),
Since the combustion exhaust gas that is proportional to the high degree of condensation flows in, the combustion exhaust gas is efficiently condensed and its latent heat is absorbed.

[0011]

[Effect] The present invention having the above-mentioned structure has the following unique effects. In the sub heat exchange section (1b), the combustion exhaust gas is efficiently condensed and its latent heat is absorbed, so that the thermal efficiency is improved.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. The embodiment shown in FIG. 1 is one in which the present invention is applied to an F · F (forced air supply / exhaust) type water heater, which has a heat exchanger (1) at the bottom of the water heater body. An air supply box provided with a body (6), a gas burner (3) of a porous combustion plate type provided on an upper portion of the can body (6), and an air supply chamber (42) provided above.
(7) is provided, a fan (4) is provided above the air supply box (7), and an exhaust passage (21) is provided below the can body (6).

The heat exchanger (1) including the water pipe (11) and the fins (12) and (12) is composed of a main heat exchange section (1a) and a sub heat exchange section (1b) arranged below the main heat exchange section (1a). It consists of and. In this embodiment, the main heat exchange part (1a) is provided with a water passage pipe part having an annular fin (1
2) It is a main water pipe (11a) equipped with (12), and similarly, the part of the water pipe of the sub heat exchange part (1b) is the sub water pipe (11b).
The bottom of the can body (6) is open, and the sub heat exchange section (1
The drain generated in b) is the drain outlet below the can body (6).
It is discharged from (8).

The main water pipe (11a) is composed of eight main water pipe parts connected in series and is composed of three upper and lower stages, each of which consists of two or three main water pipe parts. The other sub-water conduit (11b) has a single-stage structure in which three sub-water conduits are connected in series. The water passages of the main water pipe (11a) and the sub water pipe (11b) are as shown by the arrows in FIG.
The first sub-water pipe (a) at the left end of the sub-water pipe (11b) → the second sub-water pipe (b) at the center → the third sub-water pipe (c) at the right end → Reach the main water pipe (11a),
In a), the first main water pipe part (d) at the left end of the figure → the second main water pipe part (e) at the center → the third main water pipe part (f) at the right end →
4th main water pipe part (g) on the left side of the middle tier → 5th main water pipe part on the right side
(h) → 6th main water pipe section (i) at the left end of the upper stage → 7th main water pipe section (j) at the center → 8th main water pipe section (k) at the right end of the upper stage The water pipe is connected.

A distribution plate (5) as a flow rate distribution setting plate is interposed between the main heat exchange part (1a) and the sub heat exchange part (1b). As shown in FIG. 2, the distribution plate (5) is provided with a large number of through holes (50) (50), and the arrangement density of the through holes (50) (50) is the first. The part corresponding to the sub water passage part (a) is the largest, and subsequently, from the part corresponding to the second sub water passage part (b) to the part corresponding to the third sub water passage part (c), in order. It is set to be small. That is, the flow rate of the combustion exhaust gas generated by the gas burner (3) fed into the first to third auxiliary water pipe sections (a) (b) (c) by the fan (4) is as shown in FIG. The water flow pipe section (a) → the second sub water flow pipe section (b) → the third sub water flow pipe section (c) are set to decrease in order.

Therefore, when the gas burner (3) is burnt and tap water is supplied from the first sub water pipe section (a), the main water pipe (11a) and the sub heat exchange section (1a) of the main heat exchange section (1a) The water in the sub water pipe (11b) of 1b) absorbs the heat generated by the gas burner (3) from the fins (12), (12), etc., and becomes hot water from the eighth main water pipe (k). The combustion exhaust gas taken out to the outside and passing through the heat exchanger (1) is exhausted to the outside from the exhaust port (2) through the exhaust passage (21). In the endothermic action at this time, the gas burner
The action of absorbing the sensible heat of the combustion exhaust of (3) is mainly performed in the main heat exchange part (1a), and the auxiliary heat exchange part (1b) mainly removes the combustion exhaust of the gas burner (3). The action of condensing and absorbing the latent heat is performed. That is, in the sub heat exchange section (1b),
Mainly, the sensible heat is taken away and the cooled combustion exhaust gas is cooled below its dew point temperature to generate drainage, and the latent heat at that time is absorbed by the water flow in the sub water passage (11b). .

Here, since the sensible heat of the combustion exhaust gas from the gas burner (3) is mainly taken by the main heat exchange portion (1a), the exhaust gas temperature when it reaches the sub heat exchange portion (1b) is The main heat exchange section
Lower than that of (1a). In addition, the water supply is the first sub water pipe
Since it is performed from (a) and the water in the water pipe (11) absorbs heat in the water passage described above, the temperature of the sub water pipe (11b) is the first sub water pipe part (a). → The second sub-water conduit (b) → The third sub-water conduit (c) is gradually increasing. That is, the first
In the sub water pipe section (a), the temperature of the water pipe is the lowest. From this, the efficiency (condensation rate) at which the combustion exhaust gas in the sub heat exchange section (1b) is cooled below the dew point is
Sub water conduit (a) → Second sub water conduit (b) → Third sub water conduit
It becomes lower gradually in the order of (c). On the other hand, the sub heat exchange part (1
The flow rate of combustion exhaust flowing into b) is determined by the distribution plate (5).
It is set such that the first sub-water pipe section (a) → the second sub-water pipe section (b) → the third sub-water pipe section (c) decreases in order. Therefore, since the combustion exhaust gas that is proportional to the height of the condensation rate flows into each sub water passage portion, in the sub heat exchange portion (1b), the condensed component in the combustion exhaust gas is surely condensed to reduce the latent heat. The heat absorption efficiency can be improved.

The above embodiment can be modified as follows. 1. In the above embodiment, the flow rate of the combustion exhaust flowing into the sub heat exchange section (1b) is changed by changing the arrangement density of the through holes (50) (50) corresponding to each sub water passage section in the distribution plate (5). Distribution is
It was set so that the first sub-water pipe (a) → the second sub-water pipe (b) → the third sub-water pipe (c) became smaller in order (see Fig. 4), but changed as follows: It is possible to do so (see FIGS. 5 to 8. In these figures, the size of the shaded area corresponds to the distribution degree of the combustion exhaust gas flow rate).

.. As shown in FIG. 5, the first auxiliary water pipe section
Only a large number of (a) are set, and the second auxiliary water pipe (b) and the third auxiliary water pipe (c) are set equally. ． As shown in FIG. 6, it is set so that only a certain area near the most upstream end of the first auxiliary water pipe section (a) increases. ． As shown in Fig. 7, in the route from the first sub-water conduit (a) to the third sub-water conduit (c), the vicinity of the upstream end is set to be the largest, and as it goes downstream, the number decreases gradually. To be set. In addition, the exhaust amount distribution to the first auxiliary water pipe section (a) in the above is shown in FIG.
It may be replaced with that.

[0020]. As shown in FIG. 8, in each sub-water passage section, it is set so that only a certain area near the upstream side increases. In such a case, the flow rate distribution of each sub water passage part should be gradually reduced in the order of the first sub water pipe part (a) → the second sub water pipe part (b) → the third sub water pipe part (c). Set to. In any case, it is needless to say that it is most desirable to set the flow rate distribution of the combustion exhaust gas so as to maximize the drain generation amount in relation to the water temperature distribution in the sub water passage (11b).

2. In the above embodiment, the auxiliary water pipe (11b) is
Although the configuration is such that the three auxiliary water pipe portions are connected in series, the configuration may be such that two or less or four or more auxiliary water pipe portions are connected in series. When the sub-water pipe (11b) consists of one sub-water pipe part, the flow distribution of combustion exhaust is set so that the vicinity of the upstream end is large like the first sub-water pipe part (a) above or in To do. In addition, when the two sub-water pipes (11b) are connected in series with two sub-water pipe parts, or when four or more sub-water pipe parts are connected in series, the flow distribution of combustion exhaust gas is Set the above-mentioned items 1 to 3 in the quantity of sub-water passage parts.

3. In the above-described embodiment, the first sub water passage part (a) as the water supply pipe of the sub water pipe (11b) is the left end of FIG. 1, but the other sub water passage parts are the first sub water pipe part (a). The sub water pipe (11b) may be configured so that Also in this case, the flow distribution of the combustion exhaust gas is set to be gradually reduced in the order of the first auxiliary water pipe section (a) → the second auxiliary water pipe section (b) → the third auxiliary water pipe section (c).

4. In the above embodiment, the distribution plate (5) was provided as the flow rate distribution setting plate, but instead of this, as shown in FIG. 9, from the lower side of the third main water pipe part (f) to the second sub water pipe part ( b)
You may make it provide the shielding plate (5a) of the aspect which travels over the above. In such a case, the combustion exhaust gas is intensively sent to the first auxiliary water pipe section (a). The shield plate (5a) is provided with a through hole so that the combustion exhaust gas flows into the second sub water passage section (b) and the third sub water passage section (c) through the through hole. May be.

5. In the above embodiment, the distribution plate (5) is provided on the upstream side of the exhaust flow with respect to the sub heat exchange section (1b), but as shown in FIG. 10, the distribution plate (5) is provided on the downstream side of the sub heat exchange section (1b). A plate (5) may be provided. 6. In the above embodiment, the water pipe (11) is bent in a meandering manner to form a four-stage structure, in which the lowermost stage is the sub heat exchange part (1b) and the other three stages are the main heat exchange parts. Although (1a) is adopted, the auxiliary water exchange pipe (11b) of the auxiliary heat exchange part (1b), which absorbs latent heat depending on the sensible heat absorbing capacity of the main heat exchange part (1a), is a two-stage or three-stage structure from the bottom. There are multiple stages. In this case, as shown in FIG. 11 or 12, distribution plates (5) and (5) are provided on the upstream side or the downstream side of the exhaust flow in each stage of the sub-water pipe (11b), and the sub-water pipe in each stage is provided. The exhaust amount may be decreased from the upstream side portion to the downstream side portion of (11b), or the amount of exhaust gas may be reduced from that of FIG.
As shown in Fig. 5, a distribution plate (5) is installed on the most upstream side or the most downstream side of the exhaust flow in the sub water passage pipe (11b), and a plurality of stages are grouped together to form the sub water passage pipe (11b) from the upstream side to the downstream side. The exhaust amount may be reduced to the portion.

In this way, when the sub heat exchange section (1b) is constructed in a plurality of stages, water may be supplied from the water pipe (11) at the second or third stage from the bottom. Further, including the case of the above embodiment, the hot water may be taken out from the second or third stage from the top. 7. In the above embodiment, the fan (4) is provided on the air supply passage side, but it may be provided on the exhaust passage (21) side.

8. In the above embodiment, the present invention is applied to the F / F (forced air supply / exhaust) type water heater, but in addition to this water heater, a gas combustion device such as a heater for circulating heated water, or The present invention can also be applied to a gas combustion device such as a FE (forced exhaust) type water heater or a heater of the above type. 9. The present invention mainly absorbs sensible heat in the main heat exchange section (1a), and a heat exchanger of the type that mainly absorbs latent heat in the auxiliary heat exchange section (1b), as well as the main heat exchange section (1a). It is also possible to adopt a type in which only the sensible heat is absorbed and only the latent heat is absorbed in the sub heat exchange section (1b).

10. The distribution plate (5) may be provided for each sub water passage section as shown in FIG. 11. When the sub heat exchange section (1b) has the sub water passage pipes (11b) group arranged side by side, the distribution plate (5) should be interposed only between the upper sub water passage pipes (11b) group and the lower one. May be.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

[Fig. 2] Illustration of distribution plate (5)

FIG. 3 is a cross-sectional view of a sub water pipe (11b) showing a flow distribution of combustion exhaust gas in the first embodiment.

FIG. 4 is a plan view of an auxiliary water pipe (11b) showing a flow distribution of combustion exhaust gas in the first embodiment.

FIG. 5 is a plan view of a sub water pipe (11b) showing a flow distribution of combustion exhaust gas in the second embodiment.

FIG. 6 is a plan view of an auxiliary water pipe (11b) showing a flow distribution of combustion exhaust gas in a third embodiment.

FIG. 7 is a plan view of an auxiliary water pipe (11b) showing a flow distribution of combustion exhaust gas in a fourth embodiment.

FIG. 8 is a plan view of an auxiliary water pipe (11b) showing a flow distribution of combustion exhaust gas in a fifth embodiment.

FIG. 9 is an explanatory diagram of a shield plate (5a)

FIG. 10 is an explanatory view showing a state where a distribution plate (5) is provided on the downstream side of the exhaust flow with respect to the sub heat exchange section (1b).

FIG. 11 is an explanatory view of a state where the distribution plate (5) is provided on the upstream side of the exhaust flow with respect to each sub-water pipe section when the sub-water pipe (11b) is composed of a plurality of stages.

FIG. 12 is an explanatory view of a state where the distribution plate (5) is provided on the downstream side of the exhaust flow with respect to each sub water passage part when the sub water passage (11b) is configured in multiple stages.

FIG. 13 is a distribution plate on the most upstream side of the exhaust flow with respect to the sub water passage pipe (11b) when the sub water passage pipe (11b) is composed of a plurality of stages.
Explanatory drawing of the state with (5)

FIG. 14 is a distribution plate on the most downstream side of the exhaust flow with respect to the sub water passage pipe (11b) when the sub water passage pipe (11b) is composed of a plurality of stages.
Explanatory drawing of the state with (5)

FIG. 15 is an explanatory diagram of a conventional example.

FIG. 16 is an explanatory diagram of another conventional example.

[Explanation of symbols]

 (1a) ・ ・ ・ Main heat exchange part (1b) ・ ・ ・ Sub heat exchange part (3) ・ ・ ・ Gas burner (6) ・ ・ ・ Can body

Claims (3)

[Claims] 1. A main heat exchange part (1a) and a sub heat exchange part (1b) provided downstream of the exhaust stream from the gas burner (3).
Are installed side by side in the can body (6), and the water to be heated in the water pipe that passes through these heat exchange parts flows into the sub heat exchange part (1b) side and from the main heat exchange part (1a) side. In the gas combustion device configured to be taken out, the main heat exchange section (1a) absorbs the sensible heat of the combustion exhaust gas and the auxiliary heat exchange section (1b) absorbs the latent heat from the combustion exhaust gas that comes into contact therewith. A flow rate distribution setting plate for setting the flow rate distribution of exhaust gas to the sub heat exchange section (1b) is provided on the downstream side of the main heat exchange section (1a), and the upstream side of the water pipe of the sub heat exchange section (1b). Gas combustion device in which the exhaust flow rate is gradually or continuously reduced from the downstream side to the downstream side. 2. The gas combustion apparatus according to claim 1, wherein the flow rate distribution setting plate is provided on the upstream side of the sub heat exchange section (1b). 3. The gas combustion apparatus according to claim 1, wherein the flow rate distribution setting plate is provided on the downstream side of the auxiliary heat exchange section (1b).