JPS61211606A - Shroud pipe wall of furnace - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a peripheral wall ("tube wall" or "enclosure") of a furnace such as a boiler, which is constructed by welding a large number of tubes through which water passes in order to produce steam side-by-side in a membrane-like manner. A furnace whose lower part consists of a tube extending diagonally in a spiral shape, whose upper part consists of a load-carrying vertical tube, and whose lower part is suspended. , in particular to the transition from a helical tube to a vertical tube circuit. In the following description, the spirally extending oblique tubes will be simply referred to as "oblique tubes", and the load-bearing vertical tubes in the upper part of the furnace will be simply referred to as "vertical tubes".

The invention is particularly applicable to supercritical or subcritical once-through steam generators (boilers) with welded membrane tube walls.

BACKGROUND OF THE INVENTION The main problem with this type of steam generator is the support structure;
It is in the pipe configuration of the transition part from oblique pipe to vertical pipe. The diagonal tube winds multiple turns around the furnace at an angle of up to about so” from horizontal and terminates in the header below the arch of the furnace;
It transitions into a vertical tube in the upper part of the furnace. Near-horizontal diagonal pipes have less ability to carry vertical static loads and require external support structures to transfer the loads to the upright pipes.

U.S. Pat. No. 4,027,882 discloses a vertical support bar that connects the skew tubes of a furnace to the vertical tubes. U.S. Pat. No. 3,400,689 discloses providing a vertical tension member connected at its lower end to the furnace wall and supported by an upper T-spring for suspending support of the furnace tube. U.S. Pat. No. 4,116,168 discloses an arrangement in which a diagonal tube in the middle section of the furnace is connected to vertical tubes in the upper and lower sections of the furnace via forked tubes.

SUMMARY OF THE INVENTION The present invention relates to a tube wall for a furnace of a once-through steam generator with a lower section consisting of diagonal tubes fed in parallel from a ring header provided at the bottom of the furnace. The diagonal tubes extend helically upward at an angle of up to about 30' from the horizontal to wrap around the furnace at least once and terminate in vertical manifold headers spaced around the furnace. The upper part of the furnace should be removed from the diagonal pipe.
It is composed by the pipes of memory boiling. Both the diagonal pipe and the vertical pipe are welded to each other via fins or membrane plates extending along the entire length on both sides of the container pipe to form an airtight enclosure. In order to eliminate eccentric loads at the transition between the lower part (oblique pipes) and the upper part (vertical pipes) of the furnace and to simplify the pipe configuration, the pipes of the upper part and the lower part are overlapped. let

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, there is shown a schematic side view, partially in section, of a once-through steam generator 1°. The lower furnace section 12 of the device 10 is constituted by a number of diagonal tubes 12 connected to each other by membrane plates in the form of panels and extending helically upwards to a transition section 16 below the arch section 18 of the furnace. ing. In the transition section 16, the diagonal pipe 13 connects to the upper furnace section 1.
The upper end of the vertical tube 15 communicates with an outlet header 20.

As shown in FIG. 2, the diagonal tube 13
fl L-h tcnae dark hat tL-wise^i stick A-jum
- in the form of a flannel or tube wall) constitutes the lower part of the furnace. A plurality of vertical support strips 22 are suitably spaced laterally around the outer circumference of the lower furnace section 12 to carry the static load of the diagonal tube 13 and transfer the load to the vertical tube 15 of the upper furnace section. It is arranged so as to extend so as to be in contact with the outer surface of the diagonal pipe. A plurality of support bars 24 extending over the entire width of each support strip 22 are arranged at intervals in the vertical direction, and the membrane plate 26 of the diagonal tube is coupled to the support strip 22 by welding or the like. The upper end of each support strip 22 (FIGS. 5 and 8) is flared to transmit loads to a greater number of vertical tubes 15, as will be described below.

FIG. 3A shows a conventional construction of a transition section for transferring loads from support strip 22 to vertical tube 15 via fingers 30. As shown in the figure, the longitudinal centerline of the vertical tube 15 coincides with the centerline of the oblique tube 13. Lower furnace part 12
Since the static load of is carried by the support strip 22, a rotational moment is generated due to the eccentric load. In order to eliminate this rotational moment, a complex and expensive pinned linkage 28 is provided between the support strip 22 and the vertical backrest 32. In FIG. 3A, 27 is a membrane plate between the vertical tubes 15.

An improved configuration according to the present invention is shown in FIG. 3B. As shown in FIG. 3B, in accordance with the present invention, vertical tube 15 overlaps diagonal tube 13. Vertical pipe 15
The longitudinal centerline of the support strip 22 is approximately aligned with the centerline of the support strip 22,
This eliminates the rotational moment caused by eccentric loads,
Therefore, the vertical backrest required in the prior art configuration shown in FIG. 3A! Eliminating the need for I2 and link device 28. A seal 34 is interposed between the uppermost oblique pipe 13 and the membrane plate 27 of the vertical pipe 15 to ensure airtightness of the F wall. In FIG. 3B, 26 is a membrane plate of the oblique tube 13, and 30 is a finger plate.

FIG. 4 is a side view of the transition section of a conventional furnace as seen from inside the furnace. Each diagonal tube 13 extends outwardly from the furnace in the same horizontal plane and terminates in a horizontal outlet header (not shown) located outside the furnace. Since the longitudinal centerline of each vertical tube 15 coincides with the centerline of the oblique tube 13 (see also FIG. It must be bent and extended outward from the furnace wall at the height. Therefore, the lower ends of each membrane plate 27 of the vertical tube 15 are also located at different heights. Therefore, in order to hermetically seal the wall of the furnace enclosure tube, various shapes of closing plates 36 are required to seal the gap between each membrane plate 27 and the uppermost diagonal tube 15. As is apparent from FIG. 4, this is an expensive arrangement requiring extensive manual fitting and welding operations in the field during its assembly. In addition, since each vertical tube 15 must extend outward from the furnace wall and connect to an external header (not shown) at a different height, each vertical tube must be individually bent by hand. There must be.

In contrast, according to the configuration of the present invention, as shown in FIGS. 5 to 7, several oblique pipes 13 (five in the illustrated example) are provided.
As a group, it is possible to extend outward from the tube wall of the furnace. Each group of diagonal tubes 13 extends out of the furnace through the gaps between the vertical tubes 15.15 and terminates in vertical outlet manifolds 38 located at appropriate spacing around the furnace. Each manifold 38 connects to a horizontal inlet header 40. Fluid rises from the inlet header 40 through the vertical tube 15 connected thereto and flows to the outlet header 20 (FIG. 1). Vertical pipe 1
5 overlaps some of the diagonal pipes 13 in the upper part of the lower furnace section 12, bends outward in a horizontal plane below the outlet group of the diagonal pipes, and terminates in a horizontal header 40. (Figure 7).

According to this configuration of the invention, the conventional expensive closure plate 36 (
4) is eliminated, and manual welding operations on site are reduced. Furthermore, since the vertical tubes 15 can be mechanically bent all at once into a panel, there is no need to manually bend the container tubes individually as in the past.

Figures 8 and 9 are views similar to Figures 5 and 7, but from the outside of the furnace. As seen in FIG. 8, the widened end portion of one support strip has 10
The lower ends of the finger plates 30 are welded and the upper ends of the fingers are each welded to a pair of adjacent vertical tubes 15 to thereby transfer the load of the lower furnace section 12 to the upper furnace section 14. is being done. The number of finger plates 30 is greater than the number of finger plates 30 in the lower furnace section 12.
It can be increased or decreased depending on the magnitude of the static load and the width of the widened end portion of the support strip 22.

Fig. 1 is a partially sectional side view of a once-through steam generator having diagonal tubes and vertical tubes, Fig. 2 is a perspective view of a portion of the lower furnace section consisting of diagonal tubes, and Fig. 3A is a view of the transition section. FIG. 3B is a side view with a partial cross section of a conventional support structure; FIG. 3B is a view similar to FIG. 5A of the support structure of the present invention; FIG. a side view of a tube configuration of a transition section according to the present invention; FIG. 6 is a cut-away top plan view of FIG. 5; FIG. 7 is a cross-sectional view taken along line 7--7 of FIG. 5; FIG. 8 is a side view of the support structure of the present invention as seen from outside the furnace, and FIG. 9 is a cross-sectional view taken along line 9--9 in FIG.

12: Lower furnace section 13: Oblique pipe 14 , I FIG, 2 Procedural Amendment Group (Method) April 9, 1985 q;”::l + Condolences to Michibu Uga, Commissioner of the Agency (/1 indication 1985 Patent Application No. 290955
Title of the invention: Person who corrects the wall of the furnace enclosure

Claims (1)

[Scope of Claims] 1) A lower furnace section composed of a plurality of diagonal tubes spirally extending upward to a transition section in an enclosing tube wall constituting a furnace for a once-through steam generator; an upper furnace section configured of a plurality of vertical tubes having a load-bearing capacity and extending upward from the lower furnace section in fluid communication with the diagonal tubes of the lower furnace section; and a lower furnace section for supporting the lower furnace section. a plurality of vertical support strips spaced laterally around the outer periphery of the tube and connected by welding to the diagonal tube; and a plurality of vertical support strips for transferring the static load of the lower furnace section from the support strips to the vertical tube of the upper furnace section. and a vertical tube of the upper furnace section extending downwardly from the transition section so as to overlap a portion of the lower furnace section. 2) The support strip is attached so as to be located in the same plane as the outermost surface of the diagonal pipe, and the diagonal pipe and the support strip are welded together via a bar interposed between them. An enclosing tube wall according to claim 1. 3) The enclosing tube wall according to claim 2, wherein the upper end of each of the support strips is widened in a shape that widens toward the end. 4) The load transfer means comprises a plurality of vertical fingers welded at their lower ends to the widened upper ends of the support strips and each at their upper ends to a pair of adjacent vertical tubes. Enclosure pipe wall as described in range 1. 5) The wall of claim 1, wherein the central longitudinal axis of each vertical tube substantially coincides with the centerline of each support strip. 6) The wall of claim 1, wherein each diagonal tube makes at least one complete wrap around the furnace. 7) The diagonal tubes are grouped into a plurality of tube groups each consisting of a plurality of diagonal tubes arranged vertically, and each tube group penetrates between the corresponding vertical tubes at the transition portion. 2. The wall of claim 1, wherein the wall extends out of the furnace and terminates in a vertical manifold spaced around the furnace. 8) Each of the vertical tubes is bent outwardly at the transition portion in a horizontal plane below each of the groups of diagonal tubes and terminates in a horizontal header in fluid communication with the vertical manifold. The enclosing pipe wall according to item 7. 9) The diagonal pipe of the lower furnace part and the vertical pipe of the upper furnace part are:
The enclosure pipe wall according to claim 1, which is connected to each other via a membrane plate so as to constitute an airtight panel. 10) The enclosure pipe wall according to claim 1, wherein the diagonal pipe of the lower furnace section extends upward in a spiral manner at an angle of at most about 30 degrees from the horizontal.