JPS60234193A - Elbow - 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 This invention relates to an elbow interposed in the middle of a pipe for transport, and is designed to effectively reduce wear on such an elbow.

An example of such an elbow is a coal nozzle artificial elbow, which is installed in the middle of a pipe that supplies pulverized coal from the mill to a burner installed in a steam generator furnace. However, such elbows are subject to severe wear because pulverized coal, particularly relatively large coal particles, collide with the inner surface of the elbow, and the plant must therefore be frequently shut down to replace the elbows.

In order to solve this problem, conventional attempts have been made to attach a ceramic liner to the inner surface of the elbow or to make the entire elbow from a ceramic material. However, the manufacturing cost of such an elbow is high, several times the cost of a metal elbow. Moreover, ceramic liners or ceramic elbows are easily broken. t
Furthermore, even ceramic materials will eventually wear out.

The present invention has been made to solve these conventional problems.

According to the present invention, a mat formed by collecting metal fibers is attached to the inner surface of the outer bent portion of an elbow inserted in the middle of a pipe that carries fine solids in a gaseous state. Therefore, when gas carrying fine solids flows through the elbow, a portion of the fine solids are shaken off by centrifugal force and captured by the metal fiber mat. These captured fine solids are gradually packed tightly into the metal fiber mat by collision with other fine solids that are subsequently shaken off.

Therefore, the lining is finally formed by finely sized solids packed into a mat. This lining forms a very effective wear surface.

If a portion of the fine solids packed into the mat flakes off, this portion is quickly repacked by other fine solids that are thrown away.

It can therefore be said that such a wear surface is formed by the highly abrasive material itself.

A preferred embodiment of the present invention will be described in detail below with reference to the drawings.

In Figures 1-4, reference numeral 10 designates an elbow for use in a pipe 30 through which finely divided solids are carried in a gas stream.

This pipe 30 is used, for example, to transport pulverized coal from the mill to the furnace of a steam generator, which is ground in a grinding mill and carried on an air stream.

Thus, when the gas flow carrying fine solids passes through the elbow 10, many solids, particularly heavy solid particles, are thrown outward and collide with the inner surface of the outer curved portion 2 of the elbow. If such abrasive solids continue to impinge on the inner surface of the elbow, the elbow will eventually wear out and must be replaced, even if it is made from a durable material.

Therefore, according to the present invention, the outer bent portion 1 of the elbow 1o
A mat 14 formed by collecting metal fibers by brazing, for example, is attached to the inner surface of a large part of the elbow 2 (for example, the arched portion extending over 75 degrees in the case of a 9o0 elbow). Therefore, when fine solids, such as coal particles carried by the air flow, are swung outward to collide with the inner surface of the outer curved portion 12 of the elbow 10, most of the solid particles are blown away by the numerous particles of the metal fiber mat 14. Trapped in a narrow passage. The coal particles are continuously captured by the metal fiber mat so that each passageway of the metal fiber mat 14 is filled with the coal particles. The coal particles trapped by the metal fiber mat in this way are then bombarded with other coal particles that are thrown off at a fairly high speed.
It's packed quite tightly. If the packed coal particles flake off, other flung coal particles will be captured by the metal fiber mat in place of the flaked coal particles. Thus, a metal fiber mat exposed to a highly abrasive coal flow ultimately becomes a coal lining formed by a large number of packed coal particles. Some wear occurs on the metal fibers of the mat as some of the packed coal particles flake off. However, such wear is much less than the wear that occurs over an entire elbow made of metal or ceramic material. Therefore, by applying the invention, the useful life of the elbow is extended considerably.

According to this embodiment, the metal fiber mat 14 is secured to the plate 16 by a plurality of studs 18 and nuts 20 associated with these studs. That is, each stud 18 has an integrally coupled base or plate 22 that is welded to the metal fiber mat 14, as shown in detail in FIG. Also, each oak) 2
0 is seal-welded to the receiving plate 16 around its entire circumference as indicated by reference numeral 24, thereby making it fluid-tight. The receiver plate 16 has an elbow 1o around it with reference numeral 2.
Welding is performed as shown at 6, thereby completing the elbow. Flanges 28 formed at both ends of this elbow 1o
are each connected to a flange formed at the end of a straight pipe 30, for example, by bolts.

In the configuration described above, the mat 14 may be formed by assembling suitable metal fibers to capture fine solid particles, such as coal particles, and to form a matrix with numerous fine passages into which these coal particles are packed. The most suitable mat is one in which metal fibers are gathered together by brazing and formed into a mat. This mat can be easily compressed to the desired density after the metal fibers have been assembled by brazing and can be formed into any desired shape, such as that illustrated in FIGS. 2 and 3 for use in the present invention. It can be easily bent into any desired shape.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an example of an elbow according to the present invention interposed in the middle of a pipe, FIG. 2 is a sectional view taken along line 2-2 in FIG. 1, and FIG. 3 is a 3--3 in FIG. FIG. 4 is a sectional view taken along line 4--4 in FIG. 2. 10...Elbow, 12...Outside edge of elbow, 14
・・Metal fiber pine l-, 16・・Bake is plate, 18・・
Stud, 20... Nut, 22... Base, 24.2
6...Welded part, 28...Flange, 30...Pipe. (and 7 others)

Claims (1)

[Claims] An elbow inserted in the middle of a pipe that transports fine solids in a gas has an inner convex part and an outer curved part, and a mat formed by collecting metal fibers is formed on the inner surface of this outer curved part. An elbow characterized in that the mat traps a portion of fine solids in the gas flowing through the elbow, and these trapped fine solids are packed inside the mat to form a lining.