JPH07127911A - Heat exchanger - Google Patents

Abstract

PURPOSE:To make it possible to prevent a clogged state on fins and dew condensation on a heat absorption pipe located above by installing a guide board which guides a combustion exhaust gas current rising along an inner wall in a casing in such a fashion that it may face an area near the upper part of the heat absorption pipe located at the uppermost position in the casing. CONSTITUTION:Since the size of a combustion surface of a burner B is designed to be smaller than a cross section of a casing K, a combustion exhaust gas current is mixed with a combustion exhaust gas rising from the peripheral edge of the combustion face and a fresh air prevailing further on the outer peripheral side of the combustion face where the fresh air component in the exhaust gas is more increased compared with the combustion exhaust gas above the combustion face. Dew condensation is apt to be produced on the top of a heat absorption pipe H located at the uppermost position out of groups of heat absorption pipe H. A guide board 10 is installed so as to face near the heat absorption pipe H at its high position in the upper part of the casing K. Therefore, the mixed gas rising along the inner surface of the casing is guided slightly to the center of the casing by the guide board 10 and reaches the top area of the heat absorption pipe at the uppermost position, thereby preventing the generation of dew condensation in this area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger, and more particularly to a heat exchanger of a type in which a plurality of endothermic tubes are vertically arranged at the top of a can body. It is about.

[0002]

2. Description of the Related Art In recent heat exchangers such as water heaters,
In order to enable a large amount of heat exchange in a small space, the heat exchange section at the top of the heat exchanger can body has multiple fins that are arranged side by side in parallel with each other, with multiple heat absorption tubes penetrating in parallel. Then
As a whole, these endothermic tubes are connected and connected so as to form a series, and meander.

The cross-sectional structure of this heat exchanger is as shown in FIGS. 1 and 2, and normally, in order to improve the heat exchange efficiency, the heat absorbing tubes (H) (H) are provided to the fins (F). They are arranged side by side vertically and horizontally. In such a heat exchanger, a burner (a type in which combustion air is supplied through a dispersion plate (S) by a fan (M) into the can body (K) below the heat exchange section (1) is used. B) is arranged, and this combustion exhaust gas passes through between the fins (F) (F) of the heat exchange section to rise, and is discharged from the open end of the upper end of the can body through the exhaust pipe (E). .

Since this combustion exhaust rises while exchanging heat with the surface of the fin (F), the exhaust temperature decreases as it approaches the upper end of the fin (F). Therefore, if the heat exchange efficiency is sufficient, the exhaust gas temperature in contact with the upper endothermic pipe (H) (H) may have dropped to near the condensation temperature,
In this case, dew condensation may occur on the surface of the heat absorbing tubes (H) (H). Then, this condensed water causes fins (F) with a narrow space
Fins may be clogged at the upper end of (F), which may eventually cause combustion failure.

The present invention has been made in view of the above point, and is described in detail as follows: "Fin (F) (F) arranged in parallel on the upper part of the can body (K).
A large number of endothermic tubes (H) (H) penetrates, and the heated water is inserted into these endothermic tubes (H) (H), and the cans (K) below the fins (F) (F) group are inserted. ), A burner is placed inside the heat exchanger to heat exchange from the burner exhaust gas to the heated water.
An object of the invention is to prevent condensation on the surface of the heat absorbing tubes (H) (H) located above.

[0006]

[Technical Means] A technical means of the present invention for solving the above-mentioned problem is to provide a "guide plate for guiding the combustion exhaust flow rising along the inner wall of the can body (K) to the inside of the can body (K). (10) can body (K)
It was made to face the upper end of the endothermic tube (H) (H) in the upper part of.

[0007]

The above technical means operates as follows. Generally, the combustion surface of the burner arranged in the can body (K) is set smaller than the cross section of the can body (K). Then, the combustion exhaust gas from this combustion surface rises in the can body (K) and reaches the heat exchange section where the fins (F) and (F) are arranged side by side, and the heated pipes (H) and (H) are heated. Heat is exchanged with water.

Since the size of the combustion surface is smaller than the cross section of the can body (K), the combustion exhaust flow rising along the inner surface of the can body (K) is burned up from the peripheral edge of the combustion surface. The exhaust gas and the fresh air further on the outer peripheral side of the combustion surface are mixed, and the fresh air component in the combustion exhaust gas is larger than that in the combustion exhaust gas above the combustion surface. As mentioned above, dew condensation is likely to occur on the upper surface of the uppermost endothermic tube (H) (H) of the endothermic tube (H) (H) group, but the guide plate (10) is the uppermost part of the can body (K). Since it was exposed near the upper part of the upper endothermic tube (H) (H), the air-fuel mixture rising along the inner surface of the can body (K) was guided from the center of the can body by the guide plate (10). Then, the uppermost heat absorption tubes (H) and (H) are reached.

Since the air-fuel mixture has a large proportion of fresh air components as described above, it is difficult for dew to condense on the upper surface of the heat absorbing tubes (H) (H) or in the vicinity thereof. In addition,
There is almost no difference between the burning surface of the burner and the cross section of the can body (K).
A heat exchanger of a different type that allows heat exchange from outside the can (K) to the inside of the can.
Heat exchange of the type in which fresh air is introduced below the exchange section
The same can be said in the case of vessels. Can (K)
Fresh air in combustion exhaust rising along the inner wall surface
-Because the amount of ingredients is higher than other parts,
This is because the guide plate (10) also functions in the same way.

[0010]

[Effect] The upper surface of the uppermost heat-absorbing pipe, which is the most condensing part in the heat exchanger, contains a large amount of fresh air components in the combustion exhaust, so that dew condensation is less likely to occur in this part. Fins can be prevented from clogging.

[0011]

Embodiments of the present invention described above will now be described in detail with reference to the drawings. [Embodiment 1] In Embodiment 1 shown in FIG. 3, similarly to the heat exchanger shown in FIG. 1, a heat exchanging portion (1) is provided on an upper portion of a can body (K), and this heat exchanging portion has fins ( F) (F) are arranged in parallel at a fixed interval, and a plurality of endothermic tubes are arranged in parallel in the vertical and horizontal directions.
(H) (H) penetrates the fins (F) (F), and these endothermic tubes (H)
(H) is connected in series to form a meandering heated circuit as a whole, and the burner (B) is housed in the lower part of the can body (K).

The cross section of this heat exchanger is constructed as shown in FIG. 3, and includes three upper endothermic tubes (H) and (H), two middle endothermic tubes (H) and (H), and a lower one. Three endothermic tubes (H) (H) are fins (F)
Go through (F). The upper endothermic tubes (H) are arranged above the lower endothermic tubes (H), and the middle endothermic tubes (H) are located between the lower and upper endothermic tubes (H) (H). To do. Then, the water to be heated enters from the endothermic pipe (H) at one end of the lower stage and reaches the endothermic pipe (H) (H) at the other end from the endothermic pipe (H) at the other end, and then the endothermic pipe at the upper stage. Hot water is discharged through (H) (H).

The combustion surface (B ₁ ) of the burner (B) disposed below this is smaller than the cross section of the can body (K), and the burner (B) and the can body (K) are Flash air flows between them. This fresh air is a can (K)
To prevent heat distortion and the like. Also, can body (K)
Is a rectangular parallelepiped box with a rectangular cross section, and is configured as a flat box that is long in the left and right and short in the front and back. The heat absorbing tubes (H) are arranged so as to extend left and right.

In the upper part of the inner surface of the can body (K) and near the upper ends of the front wall and the rear wall, guide plates (10) (10) bent inward from the side wall of the can body (K) are provided over substantially the entire area of these side walls. Is installed,
The projecting ends are located above the center of the cross sections of the heat absorbing tubes (H) (H) on both sides of the upper stage. In this embodiment, dew condensation is likely to occur on the upper surface of the heat absorption tubes (H) (H) located on both sides of the upper end heat absorption tubes (H) (H), but due to the above-described action, the combustion surface The fresh air rising from the part outside (B ₁ ) cans (K)
As it rises along the inner surface of the combustion chamber, the combustion exhaust gas that is bent inward by the guide plate (10) and reaches the upper surface of the endothermic tubes (H) and (H) on both sides of the upper stage becomes air-rich, and dew condensation at this part occurs. Suppress. Since the degree of wetness of the combustion exhaust gas reaching this portion is significantly smaller than that of the other portions, it is possible to reliably prevent dew condensation at the portion where dew condensation is most likely to occur. In addition, the relationship between the combustion surface (B ₁ ) of the burner (B) with respect to the heat exchange section (1) and the combustor air forcibly distributed by the fan (M) in the burner box containing the burner (B). It is similar to that of FIG. 1 in that the method of supplying via (S) is adopted.

[Second Embodiment] Next, a second embodiment shown in FIG.
In addition to the above measures, is to prevent dew condensation in the central part of the upper stage, in this embodiment, the endothermic tube (H) of the upper stage
(H) is only the heat absorbing tubes (H) and (H) on both sides in Example 1. Condensation hardly occurs in the lower endothermic tube (H), but it tends to occur in the upper end tube (H) as it goes up.

Therefore, there is a possibility that dew condensation may occur in the endothermic tube (H) located at the center of the upper stage, but in this embodiment, there is no endothermic tube (H) in this portion, and the endothermic tubes (H ) (H)
Since the guide plates (10) and (10) face the upper part of the heat exchanger as in the first embodiment, the effect of preventing dew condensation in the entire heat exchanger becomes more reliable. [Embodiment 3] In the case of the above configuration, although the dew condensation prevention effect is improved, the combustion exhaust gas passing between the intermediate heat absorption tubes (H) and (H) is directly discharged to the outside, so that the heat exchange efficiency is improved. In terms of being insufficient. In order to eliminate this inconvenience, FIG. 5 and FIG.
As shown in, the fins are placed in the middle of the heat absorbing tubes (H) (H) on both sides of the upper stage.
A ridge (F ₁ ) protruding from (F) may be provided, and the top surface of the ridge (F ₁ ) may be in contact with the adjacent fin (F). In this case, the combustion exhaust gas passing between the middle-stage endothermic tubes (H) (H) is deflected to both sides by the lower section of the ridge (F ₁ ) and reaches the upper-end side endothermic tubes (H) (H). Therefore, it is possible to eliminate the inconvenience that the combustion exhaust gas in this portion is discharged as it is without heating the heat absorption tubes (H) (H).

The dew condensation preventing action of each of the above embodiments will be described in more detail. By the way, the relationship between the dew point and the air ratio of the combustion exhaust gas is as shown in FIG. 7, and the higher the air ratio, the lower the dew point. On the other hand, the air ratio of the exhaust flow near the side wall of the can body (K) is
The air ratio decreases with distance from the inner wall of the can body (K), and the air ratio of the exhaust flow flowing along the inner wall of the can body (K) is about 2.1 at maximum. Information board (10)
In the case where the above is not provided, only the exhaust gas having an air ratio of about 1.5 in the exhaust flow away from the inner surface of the side wall of the can body (K) is in the upper end heat-absorbing tube.
(H) and endothermic tube located near the inner surface of the side wall of the can body (K)
It comes into contact with (H). In this case, this endothermic tube
Condensation occurs on the upper surface of (H) as shown in the figure. However, when the guide plate (10) is provided near the upper end of the heat absorbing tube (H) as described above, the ratio of air flowing along the inner surface of the side wall of the can body (K) is high (2. (About 1) Combustion exhaust gas is mixed and comes into contact with the endothermic tube (H), and the dew point rises to prevent dew condensation.

In each of the above embodiments, the guide plates (10) (10) provided separately are attached to the inner surface of the can body (K).
It may be attached to the upper end of. For example, the peripheral edge of the frame body (11) as shown in FIGS. 10 and 11 is clamped between the flange of the can body (K) and the flange of the exhaust pipe (E), and the both flanges are caulked. Alternatively, they may be fixed by screwing, welding or the like. The long side of the frame body (11) serves as a protruding piece (12) (12) protruding inward from the upper end of the can body (K), and this will function as the guide plates (10) (10). Is. In this case, the tongue piece (13) bent downward from the outside of the long side of the frame body (11) is fitted into the can body (K) and functions as a positioning means.

In this case, by mounting the frame body (11), the projecting piece (12) has the upper endothermic tube as in the above-mentioned respective embodiments.
It goes without saying that it is configured so as to be located near the upper part of (H). In any of the above examples, the fresh air is supplied only from the bottom of the can body including the combustion air in the can body (K), but in a heat exchanger of the type in which fresh air is fed in through another route. The present invention can also be used.

In addition to the effect of lowering the temperature of the can body (K), this fresh air may function as secondary air supply air or white smoke prevention air, and is mainly supplied for the latter. It may be fresh air.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a conventional example.

[Fig. 2] Detailed sectional view of the heat exchange section (1).

FIG. 3 is a sectional view of a main part of the first embodiment of the present invention.

FIG. 4 is a cross-sectional view of a main part of the second embodiment.

FIG. 5 is a sectional view of an essential part of a heat exchange section (1) of Example 3.

FIG. 6 is a sectional view taken along line XX.

[Fig. 7] Relational diagram of air ratio and dew point

[Figure 8] Detailed view of the main part of the heat exchange part (1) when condensation occurs

[Fig. 9] Detailed view of exhaust flow when a guide plate (10) is provided

FIG. 10 is an explanatory view of another example in which the guide plate (10) is equipped.

FIG. 11 is a cross-sectional view of main parts with the frame body (11) attached.

[Explanation of symbols]

(K) ・ ・ ・ Can body (F) ・ ・ ・ Fin (H) ・ ・ ・ Endothermic tube (F ₁ ) ・ ・ ・ Raised part (10) ・ ・ ・ Guide plate

Claims (3)

[Claims] 1. A plurality of fins arranged in parallel on an upper part of a can body (K)
(F) (F) is penetrated by many endothermic tubes (H) and (H),
(H) Insert the water to be heated in (H) and
(F) In a heat exchanger in which a burner is arranged in the lower can body (K) of the (F) group, and heat is exchanged from the combustion exhaust of the burner to the heated water, the can body (K The guide plate (10) that guides the combustion exhaust flow rising along the inner wall of the inside of the can body (K) to the inside of the can body (K) is the heat absorption pipes (H) (H) located at the top of the can body (K). Heat exchanger facing near the upper part of. 2. The endothermic tube (H) (H) located at the top is a can body.
The heat exchanger according to claim 1, wherein the heat exchanger is arranged along the inner surface of the opposing side wall of (K) only in the vicinity thereof. 3. One of the fins (F) adjacent to the top surface of the fin (F) by projecting a ridge (F ₁ ) in the middle of the uppermost endothermic tube (H) (H) The heat exchanger according to claim 2, wherein the heat exchanger is in contact with the heat exchanger.