JPH08303707A - Structure of heat transfer tube penetrating part in bottom of boiler - Google Patents

Abstract

PURPOSE: To reduce a stress generated by a thermal deformation at a place where a heat transfer tube is penetrated vertically through the channel of bottom part of a boiler and prevent the generation of cracks in the heat transfer tube. CONSTITUTION: A sleeve 16, engaged with the outer surface of a heat transfer tube 11 penetrating vertically through a channel 14 provided at the bottom part 2 of a boiler and whose one end is fixed to the heat transfer tube 11 while whose outer peripheral surface is fixed to the channel 14, is provided to prevent the application of too big stress on the heat transfer tube 11 by mitigating it through the sleeve 16 even when a thermal deformation is generated between the bottom part 2 of the boiler and the heat transfer tube 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat transfer tube penetrating structure at the bottom of a boiler.

[0002]

2. Description of the Related Art An example of a conventionally used boiler will be described with reference to a vertical side view of FIG.
A boiler furnace 4 is formed by the boiler furnace wall 1, the boiler bottom portion 2, and the boiler ceiling 3, and a burner 5 is attached to the boiler furnace wall 1 in a plurality of stages.
It is designed to inject fuel into.

An air chamber 6 is formed on the outside of the boiler furnace wall 1 and the boiler bottom portion 2, and when the air sent through an air duct 7 is supplied, the inside of the air chamber 6 is filled with high-pressure air. The atmosphere is created, and combustion air is supplied into the boiler furnace 4.

A rear heat transfer section 8 is provided on the rear side (right side in FIG. 3) of the boiler furnace 4, and a reheater, a superheater and the like (not shown) are provided in the rear heat transfer section 8 and the rear section is provided. The heat transfer section 8 is connected to the exhaust gas duct 9.

The boiler furnace wall 1, the boiler bottom portion 2 and the boiler ceiling 3 forming the boiler furnace 4 are all composed of heat transfer tubes 10 (see FIGS. 4 and 5) connected by fins. Boiler furnace 4 to increase the heating surface
In the inside of, a large number of heat transfer tubes 11 extending in the up-down direction are arranged at linear positions that divide the inside of the boiler furnace 4 in the left-right width direction (positions that vertically divide the inside of the boiler furnace 4 in FIG. 4),
In order to prevent the heat transfer pipes 11 from being bent due to heat and becoming uneven, the heat transfer pipes 11 are connected to each other by connecting rods 11a at predetermined vertical positions to form an intermediate heat transfer surface 12.

The heat transfer tube 11 which constitutes the intermediate heat transfer surface 12
3 rises from the header 13 provided below the boiler bottom portion 2 as shown in FIG. 3 and FIG.
Vertically extending through the upwardly-facing U-shaped channel 14 installed between the heat transfer tubes 10 and 10 to reach the inside of the boiler furnace 4, and the upper end is the header 1 outside the boiler furnace 4.
3a.

The location where the heat transfer tube 11 constituting the intermediate heat transfer surface 12 vertically penetrates the channel 14 of the boiler bottom 2 is
Weld the heat transfer tube 11 to the channel 14 as shown in FIG.
It was fixed by 5.

[0008]

Combustion in the boiler furnace 4 causes boiler bottom 2, channel 14, and intermediate heat transfer surface 1 to be solved.
The heat transfer tubes 11 and the like that form part 2 are thermally deformed, and the amounts of extension due to this thermal deformation are different.
Bending stress in the direction in which the channel bends is generated in the portion where the channel 15 and the channel 14 are welded 15, and cracks may occur, causing the heat transfer tube 11 to crack and causing an accident in which steam or water leaks.

In order to prevent such an accident, the present invention provides
It is possible to provide a heat transfer tube penetrating structure at the bottom of a boiler in which cracks do not occur in the heat transfer tube by reducing or eliminating stress generated by thermal deformation of a portion where the heat transfer tube vertically penetrates a channel at the bottom of the boiler. It is intended.

[0010]

SUMMARY OF THE INVENTION According to the present invention, a channel provided at the bottom of a boiler is fitted to the outer surface of a heat transfer tube which vertically penetrates so that one end is fixed to the heat transfer tube and the outer peripheral surface is fixed to the channel. The heat transfer tube penetrating structure at the bottom of the boiler is characterized by including a sleeve, and the sleeve can be slidably fitted on the outer surface of the heat transfer tube to create a high pressure air atmosphere under the boiler bottom. .

[0011]

[Operation] Since the bottom of the boiler and the heat transfer tube are connected via the sleeve, even if thermal deformation occurs between the bottom of the boiler and the heat transfer tube, the sleeve acts as a cushioning material to relieve the stress. Therefore, stress is not applied directly to the heat transfer tube, and the sleeve is slidably fitted on the outer surface of the heat transfer tube, so that no stress is generated in the heat transfer tube and the atmosphere under the boiler bottom is a high-pressure air atmosphere. By
Leakage of combustion gas from sliding parts does not occur.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, in which a heat transfer tube 11 is a heat transfer tube 1 at the bottom 2 of the boiler as in FIG.
It extends vertically through the upward U-shaped channel 14 attached between 0 and 10 to the inside of the boiler furnace 4.

A sleeve 16 is fitted to the outer surface of the heat transfer tube 11 at a position where the heat transfer tube 11 penetrates the channel 14, and the outer peripheral surface of the sleeve 16 is fixed to the channel 14 by welding 17. There is.

In the embodiment shown in FIG. 1, only one end of the sleeve 16 is fixed to the heat transfer tube 11 by welding 18.

In this embodiment, even if the heat transfer tube 11 and the channel 14 are thermally deformed, the heat transfer tube 11 and the channel 14 are
Since the sleeve 16 is interposed between and, the stress is relieved by the sleeve 16 acting as a cushioning material, and the heat transfer tube 11 is not cracked and cracked.

FIG. 2 is a vertical cross-sectional view of another embodiment of the present invention, in which the heat transfer tube 11 is mounted between the heat transfer tubes 10 and 10 of the bottom 2 of the boiler and has an upward U-shaped channel 14.
And penetrates up and down to extend inside the boiler furnace 4.

A sleeve 16 is slidably fitted to the outer surface of the heat transfer tube 11 at a portion where the heat transfer tube 11 penetrates the channel 14, and the outer peripheral surface of the sleeve 16 is welded 17 to the channel 14. Is stuck to.

Below the bottom portion 2 of the boiler, an air chamber 6 is formed as in the conventional boiler described with reference to FIG. 3, and an atmosphere of high pressure air is formed.

In this embodiment, even if the heat transfer tube 11 and the channel 14 are thermally deformed, the sleeve 16 slidably fitted to the outer surface of the heat transfer tube 11 slides along the heat transfer tube 11. No stress acts on the heat transfer tube 11 and
It does not crack and crack.

Further, since the air chamber 6 in the atmosphere of high pressure air is formed below the bottom portion 2 of the boiler, the combustion gas in the boiler furnace 4 is transferred from the sliding portion between the heat transfer tube 11 and the sleeve 16 to the boiler furnace. There is no leakage to the outside of 4.

[0022]

According to the invention of claim 1, at the place where the heat transfer tube penetrates the bottom of the boiler, the bottom of the boiler and the heat transfer tube are connected through the sleeve, so that between the bottom of the boiler and the heat transfer tube. Even if thermal deformation occurs, the sleeve acts as a cushioning material, so that the stress is relieved, the stress is not applied to the heat transfer tube too much, and the crack is not generated.

According to the second aspect of the present invention, the sleeve is slidably fitted on the outer surface of the heat transfer tube, so that the thermal deformation is absorbed by the sliding and no stress is generated in the heat transfer tube, and a crack is generated. There is no effect, and by making the lower part of the boiler the atmosphere of high pressure air, there is an effect that combustion gas does not leak from the sliding portion.

[Brief description of drawings]

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

FIG. 2 is a vertical sectional view of another embodiment of the present invention.

FIG. 3 is a vertical sectional side view showing the outline of a boiler.

4 is a sectional view taken along the line IV-IV in FIG.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

FIG. 6 is a vertical sectional view of a conventional heat transfer tube penetrating structure at the bottom of a boiler.

[Explanation of symbols]

 2 Boiler bottom 11 Heat transfer tube 14 Channel 16 Sleeve

Claims (2)

[Claims] 1. A sleeve provided with a channel provided at the bottom of a boiler, which is fitted to the outer surface of a heat transfer tube that penetrates vertically and has one end fixed to the heat transfer tube and an outer peripheral surface fixed to the channel. The heat transfer tube penetration structure at the bottom of the boiler. 2. A heat exchanger tube penetrating structure for a boiler bottom portion according to claim 1, wherein a sleeve is slidably fitted to an outer surface of the heat exchanger tube, and a lower portion of the boiler bottom portion is under an atmosphere of high-pressure air.