JPS5869624A - Bent pipe portion of granular powder air-transport pipe - Google Patents

Abstract

PURPOSE:To lessen pressure loss in a bent pipe portion of a granular powder air-transport pipe by providing on the outer peripheral side of the bent pipe portion an expanding portion where a plurality of partitions are extended tangentially relative to a granular powder air current to form pockets for accumulation of granular powder. CONSTITUTION:The bent pipe portion has a granular powder inlet pipe 2 at its lower end and a granular powder outlet 3 at its side end, and an intermediate portion 1 is provided with an expanding portion on the outer peripheral side of an air current to form pockets 4. Some granular powder conducted from the granular powder inlet pipe 2 goes into the pockets 4 by its inertial force at first, and then is gradually accumulated therein to form an accumulation layer of granular powder. This accumulation layer is partially displaced, but maintained during operations, so as to function as a protective coating layer against strong collision of granular powder and remove abrasion in the bent pipe portion. The accumulation layer is adapted to guide an air current as a whole so as to form a smooth curved surface, which results in that an air current accompanying with granular powder passes through the bent pipe portion with the minimum pressure loss.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bent pipe portion of an air transport pipe for powder and granular materials, and more particularly to a bent pipe portion that takes into consideration corrosion resistance.

In air transport pipes for powder and granular materials, there is a problem that when the powder R/wood passes through the pipe, it violently collides with the inner surface of the pipe, causing wear on the inner surface of the pipe and shortening the service life of the transport pipe. Particularly in the curved pipe portion, when the flow of the powder material changes direction, the powder material intensively collides with the outer bending portion of the curved pipe portion, resulting in significant wear.

Therefore, it is no exaggeration to say that the service life of the air transport pipe depends on the appropriateness of measures against wear in the curved pipe portion.

Conventionally, various measures have been taken to prevent wear in the bent pipe section of an air transport pipe, such as treating the tl1 bent pipe section as a consumable item and replacing it with a spare bent pipe after a predetermined period of operation; (2) only the bent pipe section; 13) The inner surface of the curved pipe is covered with a wear-resistant material; (4) The radius of curvature of the curved pipe is maximized. is being attempted. However, each of these means has advantages and disadvantages, and has not always been satisfactory. Therefore, the applicant of the present invention previously disclosed in Japanese Patent Application No. 56-010114 a structure of a curved pipe portion that causes less wear. This curved pipe section is characterized by having a plurality of protrusions on the inner surface that can form particulate matter accumulation parts, and the particulate matter accumulation parts act as a kind of protective coating layer. None, minimizing wear on curved pipe sections. but,
Since the above-mentioned curved pipe section is practically provided with a hollow member on the inner surface, there is an aspect that the pressure loss of the airflow in the curved pipe section is large.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a curved pipe section of an air transport pipe for powder and granular materials that is resistant to wear due to powder and granular materials and has low pressure loss. .

In order to achieve the above object, the present invention provides a bulge on the outer circumferential side of a curved pipe part, and has a plurality of partition plates extending in the tangential direction of the powder airflow passing through the bulge. A plurality of pockets partitioned by these partition plates are configured to serve as collection areas for powder and granular material. In the above, the term tangential direction is used in a general sense.

In other words, airflow passes through a pipe with a predetermined cross-sectional area, so if the airflow is squeezed minutely, countless streamlines are assumed, and when these airflows pass through a curved pipe, there are countless streamlines. Therefore, it is not possible to determine the direction in which the partition plate extends. Therefore, the tangential direction means the range that can be assumed by grasping the flow in the pipe intuitively, and more specifically, it is an angle of ±30° with respect to the tangential direction of a large number of assumed streamlines. shall mean the allowable range of error.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 1 and FIG. 2 are diagrams showing one embodiment of the present invention. The bent pipe part according to this embodiment has a powder inlet pipe 2 at the lower end and a powder outlet at the side end. Pockets 4 for forming an accumulated layer of powder and granular material are formed in this swollen portion, divided by a plurality of partition plates 5.

The partition plate 5 extends in the direction of the inertial force of the powder and granular material indicated by the arrow in FIG. It is made to face. For convenience in manufacturing, the intermediate portion 1 has a mainly rectangular outer shape except for the inner circumferential side of the airflow, and the above-mentioned portion 5 also has a rectangular shape. Therefore, the airflow path that is divided into four by the inner peripheral part 6 of the middle part, the both side parts 7, and the opening surfaces of each pocket 4 forms a rectangular cross section.

In the above configuration, at the beginning of operation, a part of the powder and granules enters each of the pockets based on its inertia, and It gradually accumulates in the pocket from the first part, and within a short time, the second
An accumulated layer of powder and granular material as shown in the figure is formed. This accumulated layer remains in place during continued operation, with only partial displacement of the powder at the opening of the pocket.

Therefore, the stacked layer plays the role of a protective coating layer against violent collisions of powder and granules, and can eliminate wear in the curved pipe portion. The tip of the partition plate 5 is constantly in contact with powder and granules, so it gradually wears out over long periods of operation, but the amount of wear on the tip of the tip is extremely short compared to the overall length of the partition plate 5, so it has a high durability as a bent pipe section. Abrasion resistance improves minutely.

In addition, the accumulated layer as a whole forms a smooth curved surface that guides the airflow, and the airflow accompanied by the powder and granules passes through this curved pipe portion with a pressure loss that is at the limit of return.

FIG. 3 shows another embodiment of the invention. In this embodiment, a tube having the same diameter as the curved tube section is shot in contact with a position in the extension direction of the powder inlet side 10 of the curved tube section to form a bulge. A plurality of partition plates [2] are provided in this swollen portion and extend in the same direction as the inflow direction [1] of the powder airflow, forming a plurality of pockets [3]. The tip of the partition plate 2 has an elliptical shape to match the circular cross section of the curved pipe section.

This embodiment has the same effect as the embodiment described above with reference to FIGS. 1 and 2, but is characterized by the fact that powder and granules accumulate only in areas where the wear is most severe. There is. Therefore, there is an advantage that wear resistance can be easily ensured by applying it to an existing bent pipe section.

FIG. 7 shows still another embodiment of the present invention. In this example,
An elbow 23 with a large pipe diameter is connected to the powder inlet pipe 20 and the powder outlet pipe 21 via a reducer 24, and a plurality of partition plates 25 are provided around the outer circumference of the elbow 23. It is provided based on the same concept as the above, and produces the same effects. In the case of this embodiment, the cross section of the flow path of the powder or granular material in the curved pipe portion has a shape similar to an ellipse. This example,
It has the advantage of being easier to manufacture and more compact than the embodiments shown in Figures 1 and 2 above.

Comparative Experimental Example The experimental apparatus is shown in FIG. In FIG. 5, reference numeral 30 denotes a granular material hopper, and the granular material discharged from this hopper 30 via a rotary valve 3 is pneumatically transported within a transport pipe 33 using high-pressure air from a blower 32. The powder and granular material is separated by a cyclone 34 and returned to the powder and granular material hole ξ30,
Recirculate.

The high-pressure air is discharged from the cyclone 34 through a discharge pipe 35 to the outside of the apparatus. There are bent pipe sections 36 and 37 in the middle of the transport pipe 33.
A differential pressure pipe 38 is provided in the dimensional transport pipe 133, so that the pressure loss in the curved pipe portion can be suppressed. In this experimental device, various bent pipe sections were replaced with the bent pipe sections 36 and 37, and the wear status and pressure loss of each bent pipe section were compared and examined.

Experimental conditions (1) Powder sample Material: Silica sand Average particle size: 50011
m(2) Transport pipe and curved pipe part Inner diameter = 50φ or 50
°Construction: Carbon steel (3) Transport amount: 1.900 mm/h (4) Operating time: 40) 1 (5) Type of bent pipe used for replacement: A: Figure 2. Example B according to the present invention shown in FIG. 3 Example C according to the present invention shown in FIG. 3 Long elbow D according to the conventional example is used in reverse and installed in a state that does not belong to the present invention.

E: @ Gansho 56-010 ], 1. / Pertaining to what was disclosed in No. 1.

Experimental result The experimental results are shown in Table 1.

Since it is difficult to accurately compare the wear conditions, Table 1 shows a general view of the locations where the wear is severe. In types A and B of the curved pipe section, the tips of the partition plates were worn out, but this was an expected phenomenon, so the surface tenacity of the curved section was significantly improved.

In B, a part of the outer bending part was also slightly worn, but in C, which will be described later.
Compared to the case of
I'm doing it.

In the case of C, the outer bent portion is extremely worn and has the lowest durability. In case D, the partition plate is severely worn not only at the tip but also at the side. The reason for this is that an accumulated layer of powder and granular material is not formed in the pocket 4, but instead becomes a kind of dead zone, and a vortex of powder and granular material is always generated in this pocket. This causes the side surfaces to wear out, resulting in a markedly poor durability of the partition plate. In case E, the protruding member serves as the partition plate in case A. The values shown as pressure loss in Table 1 are the standard pressure loss of the bent pipe section in case C]
As O, other cases are shown as relative values,
For A, B, and C d: Pressure loss is relatively small. On the other hand, in the case of I) and 12, the pressure loss becomes significantly large. The reason why the pressure loss becomes so large in one phase of D is considered to be due to the vortex phenomenon in the pocket as described above. In the case of E, the cause is the substantial contraction of the powder flow path in the curved pipe portion.

It is clear from the above comparative experiment examples that the curved pipe part of the air transport pipe for powder and granular materials according to the present invention has the following advantages: It is effective in improving the performance and durability of pneumatic transportation equipment.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view showing an embodiment of the present invention;
The figure is an explanatory view showing a cross section of the embodiment shown in Fig. 1, Figs. 3 and 4 are sectional views showing other embodiments of the present invention, and Fig. 5 is a system diagram of experimental equipment in a comparative experiment. It is. 1... Middle part 2... Powder population 3...
・Powder outlet 4, 13...pocket 5, core
2, 25... Partition plate. Figure 2

Claims (1)

[Claims] It has a bulge provided on the outer circumferential side of the curved pipe portion, and a plurality of partition plates provided within the bulge extending in the tangential direction of the powder air flow, and is partitioned by these partition plates. 1. A curved pipe section of a powder air transport pipe, characterized in that a plurality of pockets form an accumulation section for powder and granular material.