JPH09178104A - Multi-tube once-through boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent pressure loss from increasing and increase heat absorption quantity in a multi-tube once-through boiler wherein combustion gas is made to cross with water tubes after the combustion gas is made to flow, in parallel with a direction of an axis of the water tubes, through gas passage formed between two rows of the water tubes, i.e., inner and outer water tubes. SOLUTION: In this multi-tube once-through boiler, upper and lower headers are connected by means of inner water tubes 3 and outer water tubes 4 and spaces between adjacent water tubes of each row of the water tubes are tightly closed to form a combustion gas passage 7 between the rows of the inner water tubes and the outer water tubes, and the combustion gas passage 7 is made to be in communication with a combustion chamber 9 through an inner smoke-conducting passage opening 5 and in communication with a flue 12 through an outer smoke-conducting passage opening opening 5. Thin-plate-shaped heat absorption horizontal fins 11 vertically arranged with respect to a direction of an axis of the water tubes are disposed on an outer smoke-conducting passage opening 6 of the outer water tubes 4, and thin-plate-shaped heat absorption vertical fins 15 arranged in parallel with the direction of the axis of the water tubes are disposed on a portion of the outer water tubes facing the combustion gas passage 7 in which the combustion gas flows in parallel with the axis of the tubes and through which portion the combustion gas at a temperature of not higher than 600 deg.C flows.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-tube once-through boiler in which a combustion gas passage is provided between an inner water pipe row and an outer water pipe row, and the combustion gas flows in the combustion gas passage in a direction parallel to the pipe axis. It is about.

[0002]

2. Description of the Related Art An annular upper water pipe and a lower water pipe are connected by two rows of water pipes, an inner water pipe row and an outer water pipe row, and a smoke outlet is provided between adjacent inner water tubes and adjacent outer water tubes. The combustion gas passage is formed between the inner water pipe row and the outer water pipe row by closing the end portion of the water pipe, and the combustion gas passage is formed by the inner smoke vent provided at the end of the inner water pipe. A multi-tube once-through boiler is widely used, which communicates with an inner smoke outlet and an outer smoke outlet provided at the end of an outer water pipe on the opposite side of the inner smoke outlet in the pipe axial direction and communicates with a flue.

In the boiler, the water pipe on the side facing the combustion chamber is first heated by the flame generated in the combustion chamber surrounded by the inner row of water pipes, and then, through the inner smoke vent into the combustion gas passage. Combustion gas is sent. When the combustion gas flows in the combustion gas passage in parallel with the pipe axes of the inner and outer water pipes, it heats the sides of the inner water pipe row and the outer water pipe row facing the combustion gas passage, and the combustion exhaust gas after heating flows to the outer side. Exhausted through the smoke outlet and flue. In this case, the inner water pipe is heated strongly because it receives heat directly from the flame, but the outer water pipe is not heated as much as the inner water pipe. Also, various heat absorbing fins are attached to the water pipe to increase the amount of heat absorbed, but the heat absorbing fins interfere with the flow of combustion gas and increase the pressure loss. In order to avoid this, how to attach the heat absorbing fin was limited.

[0004]

The problem to be solved by the present invention is that after the combustion gas is made to flow in the combustion gas passage provided between the two inner and outer rows of water pipes in parallel with the axial direction of the water pipe. In a multi-tube once-through boiler configured to intersect with the water pipe at
It is to increase the heat absorption amount of the outer water pipe while suppressing the increase of pressure loss.

[0005]

[Means for Solving the Problems] Two rows of water pipes, an inner water pipe and an outer water pipe, connect between an annular upper pipe header and a lower pipe header, and a smoke outlet portion is provided between adjacent water pipes of each water pipe column. By closing except the above, a combustion gas passage is formed between the inner water pipe row and the outer water pipe row, and the combustion gas passage communicates with the combustion chamber for combustion by the inner smoke passage provided at the end of the inner water pipe, In a multi-tube once-through boiler that connects a flue that discharges combustion exhaust gas with a combustion gas passage by an outer smoke outlet provided at the end of the outer water pipe that is opposite to the smoke outlet in the axial direction, the outer smoke outlet of the outer water pipe A thin plate-shaped horizontal fin for heat absorption perpendicular to the axial direction of the water pipe, the combustion gas passage of the outer water pipe in which the combustion gas flows parallel to the pipe axis, and the combustion gas temperature flowing in the combustion gas passage is 600. A thin plate-shaped vertical for heat absorption parallel to the axial direction of the tube at a temperature lower than ℃ Providing a fin.

[0006]

The heat absorbing fins provided in the combustion gas flow passage are provided so as to be parallel to the flow direction of the combustion gas in order to prevent an increase in pressure loss. When the combustion gas passage is provided between the inner water pipe and the outer water pipe, and the combustion gas is made to flow in the combustion gas passage in a direction parallel to the pipe axis, and then the combustion gas is made to flow in a direction intersecting with the outer water pipe. Since the combustion gas flows in two ways, parallel and perpendicular to the tube axis direction, the portion where the heat absorbing fins are provided is limited. However, in the portion where the combustion gas flows parallel to the tube axis, the heat absorption fins parallel to the tube axis direction are used, and in the portion where the combustion gas intersects the water tube, the heat absorption fins perpendicular to the tube axis direction are used. By providing two types of heat absorbing fins on the water pipe of the book, it is possible to always prevent the flow of the combustion gas from being obstructed. Further, when the combustion gas temperature is too high, the fins are overheated, so the vertical fins for heat absorption have a combustion gas temperature of 600.
Provide only in the part lower than ℃.

[0007]

An embodiment of the present invention will be described with reference to the drawings.
An annular upper pipe header 1 is provided on the upper part of the can body, and an annular lower pipe header 2 is also provided on the lower part, and an inner water pipe 3 and an outer water pipe 4 which are arranged in an annular shape are connected between the upper and lower pipe headers. Inner water pipe 3
The outer water pipe 4 and the inner smoke outlet 5 and the outer smoke outlet 6 are not provided, and the adjacent water pipes are closed by the closing fins 8 parallel to the pipe axial direction. A combustion gas passage 7 is formed between the outer pipe 3 and the outer water pipe 4. A portion surrounded by the inner water pipe 3 is a combustion chamber 9, and a burner 10 is provided above the combustion chamber 9. The combustion chamber 9 and the combustion gas passage 7 are connected to the upper portion of the inner water pipe by the inner smoke outlet 5 without the closing fins 8, and the combustion exhaust gas is discharged from the outer smoke outlet 6 without the closing fins 8 at the lower portion of the outer water pipe. The exhaust flue 12 and the combustion gas passage 7 are communicated with each other. The surface of the outer water pipe 4 facing the combustion gas passage has a combustion gas temperature of 600
A thin plate-shaped heat-absorbing vertical fin 15 parallel to the pipe axis direction at a portion lower than ℃, and a thin plate-shaped heat absorption horizontal fin that is perpendicular to the pipe axis direction at the outer smoke outlet 6 portion of the outer water pipe 4. Fin 11
There are many. The upper and lower pipe pulling parts are covered with the refractory material 14, and the entire can body is covered with the heat insulating material 15.

When the burner 10 is burned, combustion gas is generated in the combustion chamber 9, and first, the surface of the inner water pipe 3 on the combustion chamber 9 side is heated. Subsequently, the combustion gas reaches the inside of the combustion gas passage 7 through the inner smoke outlet 5 and heats the inner water pipe 3 and the outer water pipe 4 facing the combustion gas passage 7 while flowing in the combustion gas passage 7 from the upper portion to the lower portion. At this time, the heat of the combustion gas is absorbed by the outer water pipe 4 also through the heat absorbing vertical fins 15,
Since the heat-absorbing vertical fins 15 are provided in parallel with the flow of the combustion gas, they do not cause much resistance. When the combustion gas reaches the outer smoke vent portion 6, the combustion gas flows from the combustion gas passage 7 toward the flue 12 across the outer water pipe. At this time, the heat of the combustion gas heats the heat absorbing horizontal fins 11,
The outer water pipe 4 is heated through the heat-absorbing horizontal fins 11, but the heat-absorbing horizontal fins 11 are provided in parallel with the flow of the combustion gas, and therefore do not cause much resistance. Inner water pipe 3
The water in the outer water pipe 4 is heated by heating the water pipe, becomes steam, and is taken out through the upper header 1. The combustion exhaust gas having a lowered temperature is discharged through the flue 12.

[0009]

By implementing the present invention, the amount of heat absorbed by the outer water pipe can be increased while suppressing an increase in pressure loss, and efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is a partially enlarged view of FIG. 2;

[Explanation of symbols]

 1 Upper Pipe Head 2 Lower Pipe Head 3 Inner Water Pipe 4 Outer Water Pipe 5 Inner Smoke Port 6 Outer Smoke Port 7 Combustion Gas Passage 8 Closing Fin 9 Combustion Chamber 10 Burner 11 Horizontal Fins for Heat Absorption 12 Flue 13 Refractory 14 Insulation 15 Vertical fins for heat absorption

Claims (2)

[Claims] 1. An annular upper water pipe and a lower water pipe are connected by two rows of water pipes, an inner water pipe and an outer water pipe, and the adjacent water pipes of each water pipe row are closed except for a smoke outlet. By that,
A combustion gas passage is formed between the inner water pipe row and the outer water pipe row,
The combustion gas passage communicates with the combustion chamber where combustion is performed by the inner smoke outlet provided at the end of the inner water pipe, and the combustion exhaust gas is exhausted by the outer smoke outlet provided at the end of the outer water pipe opposite to the inner smoke outlet in the pipe axial direction. In a multi-tube once-through boiler that communicates a flue gas that discharges with a combustion gas passage, a thin plate-shaped heat-absorbing horizontal fin that is perpendicular to the axial direction of the water pipe, and the outer water pipe A multi-tube once-through boiler, wherein a thin plate-shaped vertical fin for heat absorption parallel to the tube axis direction is provided in a portion facing the combustion gas passage through which the combustion gas flows parallel to the tube axis. 2. The multi-tube once-through boiler according to claim 1, wherein vertical fins for heat absorption are provided only in a portion where the temperature of the combustion gas flowing through the combustion gas passage is lower than 600 ° C. boiler.