JP3038627B2 - Water tube boiler - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water pipe boiler having a structure in which an upper header or an upper body and a lower header or a lower body are connected to each other by a plurality of inner water pipes and outer water pipes.

[0002]

2. Description of the Related Art FIG. 4 is a plan sectional view showing the structure of a conventional water pipe boiler of this type. As shown in the drawing, a conventional water tube boiler communicates an upper header or upper shell (not shown) and a lower header or lower shell (not shown) with a number of inner water pipes 3 and outer water pipes 4. A combustion gas passage 5 is formed between an annular water pipe wall composed of a row of inner water pipes 3 and an annular water pipe wall composed of a row of outer water pipes 4, and an opening 1 extending over the entire length of the inner water pipe wall.
0 to provide communication between the combustion chamber 8 formed in the inner water pipe wall and the combustion gas passage 5, and an opening 11 extending over the entire length of the outer water pipe wall to provide the combustion gas passage 5 and the flue 12
And the inner water pipe 3 facing the combustion gas passage 5
And the outer water pipe 4 is provided with a fin 13 having an angled cross section.

[0003]

In the water pipe boiler of the above-mentioned conventional structure, the combustion gas which has passed through the opening 10 from the combustion chamber 8 is supplied to the water pipe walls of the inner and outer water pipes 3 and 4 and to the fin having an angled cross section. Flows through the combustion gas passage 5 formed by the above. In other words, by flowing through a zigzag-shaped passage that continuously changes direction in a direction close to a right angle, it repeatedly collides with the surface of the inner water pipe 3 and the outer water pipe 4 or one side of the fin 13 having an angled cross section, forcing the water pipe and the fin. Heat is exchanged by convective heat transfer, and the gas goes to the flue 12 while lowering the gas temperature.

However, when flowing through the zigzag-shaped passage as described above, the inner water pipe 3 and the outer water pipe 4 provided with the angled fins 13 which are disposed near the opening 10 (combustion chamber outlet), in particular. There were the following problems. (1) The temperature of the combustion gas is high in the vicinity of the opening 10, and the fin having an angled cross section provided in the water pipe in this region comes into contact with the high-temperature gas, and thus has a problem of damage due to high-temperature oxidation.

(2) A fin 13 having an angled cross section
There was a risk that fins or cracks would occur in the water tube due to thermal stress at the tip of the water tube.

(3) The inner and outer sides of the combustion gas passage 5 are provided with fins having an angled cross section on the majority of the two rows of water pipes 3 and 4, so that the combustion gas passes through the combustion gas passage. 5 continuously flows over the entire length while repeating the direction change, so that the ventilation resistance accompanying the direction change can be increased. In particular, since the temperature of the combustion gas is high near the outlet (opening 10) of the combustion chamber 8, the volume flow rate of the combustion gas increases and the ventilation resistance increases, so that there is a problem that it is necessary to increase the ventilation power of the blower. .

The present invention has been made in view of the above points, and eliminates the above-mentioned problems, and in particular, reduces the ventilation resistance of the combustion gas passage.
An object of the present invention is to provide a water tube boiler that requires only a small amount of blowing power.

[0008]

SUMMARY OF THE INVENTION To solve the above problems, the present invention provides an upper header or upper body and a lower header or lower.
The body is formed in an annular shape, and the upper header or the upper body is
Lower lower header or lower body with multiple inner and outer water pipes
Connect the inner water pipe closely or by fin
Arrange the outer water pipes closely or with fins
And are arranged as an annular water pipe wall.
Combustion gas passage between water pipe wall and outer water pipe wall
And an inner water pipe facing the combustion gas passage and the outer water pipe
A fin with an angled cross section on one or both of
Attached in the longitudinal direction of the pipe, burning inside the annular water pipe wall of the inner water pipe
A chamber is formed and an opening is formed in the annular water pipe wall of the inner water pipe.
To provide communication between the combustion chamber and the combustion gas passage,
An opening is provided in the annular water pipe wall of the outer water pipe to form the combustion gas.
In a water tube boiler with a structure that connects the passage and the flue,
The inner water pipe and the outer water pipe are formed in an angle shape over a predetermined length of the combustion gas passage from the openings provided in the row of the inner water pipes in which the combustion gas is at a high temperature and the volume flow rate is large toward the downstream of the flow of the combustion gas. and fin teeth water tube, this part
Wherein the ventilation resistance of the combustion gas passage is reduced .

[0009]

As described above, the combustion gas has a high temperature and a large volume flow rate.
Combustion gas through openings in the row of inner water pipes
A predetermined length of the combustion gas passages
The inner and outer water pipes are angled without fins
Use a water pipe to reduce the ventilation resistance of the combustion gas passage in this area.
In the high temperature region where the volumetric flow rate of combustion gas is large,
By the inner water pipe and the fin with the angled cross section
It is not possible to continuously change the direction in a direction close to a right angle continuously.
Therefore, the ventilation resistance can be reduced and the blowing power is small.
I just need to.

[0010]

[0011]

An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 show the structure of a water tube boiler according to one embodiment of the present invention. FIG. 1 is a longitudinal sectional view, and FIG. 2 is a transverse sectional view. The upper header or upper shell 1 and the lower header or lower shell 2 are both formed in an annular shape, and the upper header or upper shell 1 and the lower header or lower shell 2 are formed of a large number of inner water tubes 3.
And a plurality of outer water pipes 4.

A large number of inner water pipes 3 are arranged in close contact with each other and are configured as annular water pipe walls. Further, the outer water pipes 4 are connected and arranged with each other by fins 15 and are configured as annular water pipe walls. A combustion gas passage 5 is formed between the water pipe wall of the inner water pipe 3 and the water pipe wall of the outer water pipe 4, and a casing 6 is provided outside the water pipe wall of the outer water pipe 4 to form a gas tight structure. Heat insulation 7 outside
Is provided.

A combustion chamber 8 is formed in the annular water pipe wall of the annular inner water pipe 3. A combustion device 9 is provided inside the upper header or the upper body 1.
An opening 10 is provided at a predetermined position of the water pipe wall of the inner water pipe 3 over the entire length of the water pipe, and the combustion chamber 8 and the combustion gas passage 5 are communicated. Further, an opening 11 is provided at a predetermined position on the water pipe wall of the outer water pipe 4 over the entire length of the water pipe, and the combustion gas passage 5 and the flue 12 are communicated.

The inner water pipe 3 and the outer water pipe 4 are arranged so as to be shifted from each other by a substantially half pitch in the circumferential direction, and the side surfaces of the inner water pipe 3 and the outer water pipe 4 facing the combustion gas passage 5 have an angled cross section over the entire length of the water pipe. Fin 13 is provided,
Several of the inner water pipes 3 and the outer water pipes 4 facing a certain length in the downstream direction from the opening 10 in the combustion gas passage 5 (3 in FIG.
This is a water pipe 14 having no fins 13 having an angled cross section.

Next, the operation of the water tube boiler having the above structure will be described. The combustion gas burned in the combustion chamber 8 passes through the opening 10.
After reaching the combustion gas passage 5, heat exchange is mainly performed between the water pipe wall of the inner water pipe 3, the water pipe wall of the outer water pipe 4 and the angled fin 13 by convection heat transfer, and At the opening 11 provided in the water pipe wall of the water pipe 4, the water pipe 4 merges and goes to the flue 12. In this case, the inner water pipe and the outer water pipe near the opening 10 of the combustion chamber 8, that is, near the outlet of the combustion chamber 8 are angle-shaped finless water pipes 14. As in the conventional example shown in FIG.
The angled fin 13 is not oxidized at high temperature.
Further, the temperature of the fin 13 rises due to heat exchange with the combustion gas, and a thermal stress is generated due to a temperature difference between the fin, the water pipe and the fin attachment portion, and the fin and the water pipe do not crack.

Further, when the combustion gas is at a high temperature, the volume flow rate of the combustion gas becomes large, and in the region where the volume flow rate is large, that is, in the vicinity of the opening 10, the inner water pipe 3 and the fin 13 having an angled cross section as in the prior art are used. Since the direction change close to a right angle is not repeated continuously, ventilation resistance can be reduced.

FIG. 3 is a cross sectional view showing the structure of a water tube boiler according to another embodiment of the present invention. The difference between the water tube boiler of FIG. 3 and the water tube boiler of FIGS. 1 and 2 is that, in FIGS. 1 and 2, the row of the inner water tubes 3 arranges adjacent water tubes in close contact with each other. On the other hand, in FIG. 3, the row of the inner water pipes 3 is similar to the row of the outer water pipes 4 in that the water pipes are connected to each other by fins 16, and the other points are the same.

[0018]

As described above, according to the present invention,
The inner water pipe and the outer water pipe are formed in an angle shape over a predetermined length of the combustion gas passage from the openings provided in the row of the inner water pipes in which the combustion gas is at a high temperature and the volume flow rate is large toward the downstream of the flow of the combustion gas. A finless water tube and this part
Since the ventilation resistance of the combustion gas passage is reduced, an excellent effect of realizing a water tube boiler having a can body with small blowing power can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a structure of a water tube boiler according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a structure of a water tube boiler according to one embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a structure of a water tube boiler according to another embodiment of the present invention.

FIG. 4 is a plan sectional view showing the structure of a conventional water pipe boiler of this type.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper header or upper body 2 Lower header or lower body 3 Inner water pipe 4 Outer water pipe 5 Combustion gas passage 6 Casing 7 Insulating material 8 Combustion chamber 9 Combustion device 10 Opening 11 Opening 12 Flue 13 Cross-section fins 14 Water tube without angled fins 15 Fin 16 Fin

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-178802 (JP, A) JP-A-1-151004 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F22B 21/06 F22B 37/10

Claims (1)

(57) [Claims] 1. An upper header or upper body and a lower header or lower body are both formed in an annular shape, and the upper header or upper body and the lower header or lower body are communicated with a number of inner water pipes and outer water pipes. The inner water pipes are connected closely or by fins and arranged as an annular water pipe wall, and the outer water pipes are connected closely or by fins and arranged as an annular water pipe wall. A combustion gas passage is formed between the outer water pipe and the water pipe wall, and a fin having a cross section at an angle is attached in a longitudinal direction of the pipe to one or both of the inner water pipe and the outer water pipe facing the combustion gas passage. Forming a combustion chamber in the annular water pipe wall of the inner water pipe,
An opening is provided in the annular water pipe wall of the inner water pipe to allow the combustion chamber to communicate with the combustion gas passage, and an opening is provided in the annular water pipe wall of the outer water pipe to allow the combustion gas passage and the flue to communicate. In a water pipe boiler having a communication structure, a combustion gas passage having a predetermined length from an opening provided in the row of the inner water pipes in which combustion gas has a high temperature and a large volume flow rate toward a downstream of a flow of the combustion gas. The inner water pipe and the outer water pipe with an angled finless water pipe
A water pipe boiler characterized in that the ventilation resistance of the combustion gas passage in this portion is reduced .