JPH05126302A - Water tube boiler - Google Patents

Abstract

PURPOSE:To improve the thermal efficiency by forming a zigzag flow channel in which the direction of the flow channel changes continuously by means of inside and outside rows of water tubes and mountain-shaped fins on them. CONSTITUTION:A zigzag flow channel is constituted by changing the direction of the flow channel 5 continuously by nearly a right angle, the flow channel 5 being formed by mountain-shaped fins 13 and/or three or four rows of inside and outside water tubes. The combustion gas is guided by this flow channel 5, and after it collides with the mountain-shaped fins 13 installed to the inside water tubes 3, it changes its direction by substantially a right angle, then it collides with one sides of mountain-shaped fins 13 installed to the outside water tubes 4, and this is repeated successively and the combustion gas goes to a flue 12. With this arrangement the surfaces of the side face sections of the inside and outside water tube rows 3,4 which become a stagnant flow zone and generate, vortexes, etc., contributing only a little to heat transfer change into heat transfer faces that are perpendicular to the gas flow, and in this zone it is possible to generate forcibly heat transfer by turbulent flows and raise the thermal efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water tube boiler, and more particularly to a can body structure of the water tube boiler.

[0002]

2. Description of the Related Art Conventionally, the upper and lower pipes or the upper and lower shells are connected by a number of water pipes and arranged as inner and outer annular water pipe walls to form a combustion gas passage between both water pipe walls. A water tube boiler is known in which an opening is provided over the entire length to connect the combustion chamber and the combustion gas passage to each other, and an outside water tube wall is provided with an opening over the entire length of the tube to connect the combustion gas passage and the flue. There is.

[0003]

However, in the water tube boiler having the above-mentioned structure, there is room for improvement in terms of thermal efficiency when the water tube used is a raw tube.
Further, in an example in which a large number of fins, studs, etc. are attached to the water pipe to improve the thermal efficiency, there are problems such as manufacturing restrictions and ventilation resistance.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a water tube boiler with improved thermal efficiency and less manufacturing restrictions.

[0005]

In order to achieve the above object, in a water pipe boiler of the present invention, an upper pipe header or an upper cylinder and a lower pipe cylinder or a lower cylinder are both formed in an annular shape, and these upper and lower pipe cylinders or upper and lower cylinders are formed. The body is connected by a number of inner water pipes and outer water pipes, and these inner water pipes are arranged in close contact or fins to form an annular water pipe wall, and these outer water pipes are arranged in close contact or fins to form an annular water pipe wall. And forming a combustion gas passage between the water pipe wall of the inner water pipe and the water pipe wall of the outer water pipe, and a cross section of either or both of the inner water pipe and the outer water pipe facing the combustion gas passage. A fin having a chevron shape is attached in the longitudinal direction of the pipe to form a combustion chamber in the annular water pipe wall of the inner water pipe, and an opening is provided in the water pipe wall of the inner water pipe to connect the combustion chamber and the combustion gas passage. It was, and is characterized in that communicated the combustion gas passage and flue opening provided in the water tube wall of the outer water tube.

[0006]

According to the present invention having the above-described structure, the flow path formed by the mountain-shaped fins and / or the row of inner and outer water pipes has a minimum increase / decrease in the flow path width within the water pipe unit pitch angle stroke with respect to the gas flow. Then, it is possible to continuously change the direction of the flow path in a shape close to a right angle, that is, to form a zigzag flow path. The combustion gas is guided to this flow path and collides with the side surface of the inner water pipe and / or one side of the chevron fin attached to the inner water pipe, and then turns around at a right angle, and then the side surface of the outer water pipe and / or Or, it collides with one side of the mountain-shaped fin attached to the outer water pipe. Repeat this for the inner and outer water pipes in sequence,
Head to the flue. As a result, the side surface of the inner / outer row water pipes, which has a flow stagnation region and eddies are generated, which has a low contribution to heat transfer, changes into a heat transfer surface orthogonal to the gas flow due to the fins of the chevron, and this region is disturbed. It is possible to forcibly generate the flow heat transfer to improve the thermal efficiency. Further, since the flow passage direction is changed by reducing the increase or decrease of the flow passage width, it is possible to reduce the ventilation loss resistance due to the stagnant region of the flow or the generation of the vortex.

Further, the surface of the water pipe covered with the mountain-shaped fin becomes a shadow part of the combustion gas passage, and its contribution to heat transfer is very low. By integrally welding both ends of the chevron fin with the water pipe, this portion can be isolated from the combustion gas, and thus can be excluded from the heat transfer area.
That is, by excluding the surface of the water pipe that does not contribute to heat transfer due to the shadow of the fins of the mountain shape from the heat transfer area, it is possible to configure the heat transfer area only by the surface effective in heat transfer, and the heat transfer area is limited. The heat transfer can be improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a water tube boiler according to the present invention will be described below with reference to FIGS. Both the upper head (or upper body) 1 and the lower head (or lower body) 2 are formed in an annular shape, and these upper and lower heads (or upper and lower body)
1, 2 are connected by many inner water pipes 3. These inner water pipes 3 are connected by fins 14 and arranged as an annular water pipe wall. In addition, vertical alignment (or vertical body)
1, 2 are connected by a number of outer water pipes 4. these,
The outer water pipes 4 are connected by fins 15 and arranged as an annular water pipe wall. Water pipe wall of inner water pipe 3 and outer water pipe 4
A combustion gas passage 5 is formed between the outer wall of the outer water tube and a casing 6 to form a gas tight structure, and a heat insulating material 7 is provided on the outer side of the casing 6.

A combustion chamber 8 is formed in the annular water pipe wall of the inner water pipe 3. A combustion device 9 is provided inside the upper header (or the upper body) 1. The water pipe wall of the inner water pipe 3 is provided with an opening 10 over the entire length of the water pipe, and the combustion chamber 8 and the combustion gas passage 5 are communicated with each other. Opening 1 over the entire length of the water pipe on the water pipe wall of the outer water pipe 4.
1 is provided, and the flue 12 and the combustion gas passage 5 are communicated with each other.

The inner water pipe 3 and the outer water pipe 4 are arranged so as to be displaced by approximately half pitch angles in the circumferential direction, and mountain-shaped fins 13 are provided on the inner water pipe 3 and the outer water pipe 4 facing the combustion gas passage 5 over the entire length of the water pipe. There is. The chevron fins 13 may be provided on either the inner water pipe 3 or the outer water pipe 4.

FIG. 4 shows another embodiment of the water tube boiler of the present invention. In the embodiment shown in FIG. 4, adjacent inner water pipes 3 are arranged in close contact with each other. Other configurations are similar to those of the embodiment shown in FIG. 2 and 4, the outer water pipe may have a larger diameter than the inner water pipe, and the outer water pipes 4 may be arranged in close contact with each other.

The embodiment shown in FIG. 5 is another embodiment in which angle fins are attached to a part of the inner water pipe 3 and the outer water pipe 4 in the longitudinal direction of the pipe. In the present embodiment, fins 13 having a chevron cross section are attached to the inner water pipe 3 facing the combustion gas passage 5, and the outer water pipe 4 facing the combustion gas passage 5 has a chevron cross section. The fin 13 is attached over a length corresponding to the finless portion of the inner water pipe 3. The other structure is the same as that of the above-mentioned embodiment.

Next, the operation of the water pipe boiler shown in FIGS. 1 to 5 constructed as described above will be described. Combustion gas generated in the combustion device 9 goes from the combustion chamber 8 to the opening 10 and branches there, and the combustion gas passage 5 passes through the inner and outer water pipes 3, 4 and / or
Alternatively, it is guided by the mountain-shaped fins 13 and flows at a right angle to the longitudinal direction of the pipe, merges at the opening 11, and is discharged from the flue 12 to the outside.

However, the flow path formed by the mountain-shaped fins 13 and / or the row of inner and outer water pipes makes the flow path perpendicular to the gas flow by reducing the increase and decrease of the flow path width within the water pipe unit pitch angle stroke as much as possible. It is possible to continuously change the direction in a manner close to, that is, to form a zigzag channel. The combustion gas is guided to this flow path, collides with the side surface of the inner water pipe 3 and / or one side of the mountain-shaped fin 13 attached to the inner water pipe 3, and then changes its direction at a substantially right angle. -Shaped fins 1 attached to the side and / or outer water pipe 4
Hit one side of 3. This is repeated for the inner and outer row water pipes in sequence to the flue 12. As a result, conventionally, the side surface of the inner and outer water pipes, which has a stagnation region of flow and has a low contribution to heat transfer due to generation of vortices, changes into a heat transfer surface orthogonal to the gas flow due to the angled fins 13, and in this area. Turbulent heat transfer is forcibly generated to improve thermal efficiency.

Further, the inner and outer water pipes 3 and 4 and the mountain-shaped fin 13
The flow channel formed by has a substantially constant flow channel width,
That is, since the direction of the flow path is changed by reducing the increase / decrease in the flow path width, it is possible to reduce the ventilation loss resistance due to the stagnant region of the flow or the generation of vortices. Further, the surfaces of the inner and outer water pipes 3 and 4 covered by the chevron fins 13 become a shadow part of the combustion gas passage, and the contribution to heat transfer is very low. By integrally welding both ends of the mountain-shaped fin 13 to the water pipe,
This portion can be isolated from the combustion gases and thus excluded from the heat transfer area. That is, by excluding the water pipe surface that is behind the mountain-shaped fins 13 and does not contribute to heat transfer from the heat transfer area, the heat transfer area can be configured only by the surface effective in heat transfer, and the limited heat transfer area can be achieved. The heat transfer in the heat area can be improved. Yamagata's fin 1
If both ends of 3 are integrally welded to the water pipes 3 and 4, it is useful for relaxing the thermal stress of the fin 13.

[0016]

As described above, according to the present invention, a zigzag flow passage whose flow passage direction is continuously changed is formed by the inner and outer water pipe rows and the mountain-shaped fins. Vortices are generated and the contribution to heat transfer is low.The side surface of the inner and outer water pipes changes into a heat transfer surface that is orthogonal to the gas flow due to the fins, and turbulent heat transfer is forcibly generated in this area. The thermal efficiency can be improved. Moreover, according to the present invention, since the structure can be formed only by attaching the fins in the longitudinal direction of the water pipe, there are few restrictions on manufacturing.

Further, according to the present invention, since the direction of the flow passage is changed by reducing the increase / decrease in the width of the flow passage, it is possible to reduce the ventilation loss resistance due to the generation of the stagnant region of the flow or the vortex.

Further, according to the present invention, the heat transfer area can be constituted by only the surface effective for heat transfer by excluding the water pipe surface which is a shade of the fin of the mountain and does not contribute to heat transfer from the heat transfer area. It is possible to improve heat transfer in a limited heat transfer area.

[Brief description of drawings]

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

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

FIG. 3 is a cross-sectional view of a water pipe and a mountain fin in an embodiment of the water pipe boiler according to the present invention.

FIG. 4 is a cross-sectional view showing another embodiment of the water tube boiler according to the present invention.

FIG. 5 is a vertical sectional view showing still another embodiment of the water tube boiler according to the present invention.

[Explanation of symbols]

 1 Upper Heading or Upper Body 2 Lower Heading or Lower Body 3 Inner Water Tube 4 Outer Water Tube 5 Combustion Gas Passage 6 Casing 7 Insulation Material 8 Combustion Chamber 9 Combustor 10 Opening 11 Opening 12 Flume 13 Yamagata Fin 14 Fin 15 fins

Claims (3)

[Claims] 1. An upper pipe head or an upper body and a lower pipe body or a lower body are both formed in an annular shape, and these upper and lower pipe bodies or the upper and lower body are communicated by a number of inner water pipes and outer water pipes, and these inner water pipes are closely contacted with each other. Or, the fins are connected by fins to be arranged as an annular water pipe wall, and the outer water pipes are closely contacted or connected by fins to be arranged as an annular water pipe wall, and the water pipe wall of the inner water pipe and the water pipe wall of the outer water pipe are arranged. A combustion gas passage is formed between the inner water pipe and the outer water pipe facing the combustion gas passage, and a fin having a chevron cross section is attached in the pipe longitudinal direction to either or both of the inner water pipe and the annular water pipe of the inner water pipe. A combustion chamber is formed in the wall, an opening is provided in the water pipe wall of the inner water pipe to communicate the combustion chamber with the combustion gas passage, and an opening is provided in the water pipe wall of the outer water pipe to form the combustion gas passage. With a flue A water tube boiler characterized by being connected. 2. The water pipe boiler according to claim 1, wherein fins having a chevron cross section are attached to one or both of the inner water pipe and the outer water pipe facing the combustion gas passage over the entire length of the water pipe. 3. A fin having a chevron cross section is attached to a part of the entire length of the water pipe on the inner water pipe facing the combustion gas passage, and a fin having a chevron cross section on the outer water pipe facing the combustion gas passage. The water pipe boiler according to claim 1, wherein the water pipe boiler is attached over a length corresponding to the finless portion of the.