JPH026959B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a bent pipe that forms a curved air transport path for powder and granular material. [Prior Art] Recently, as a method for transporting powder and granular materials such as coal powder or abrasive powder, a powder pneumatic transportation method has been put into practical use, in which the powder and granular material is transported along with an air flow. In such a powder pneumatic transportation method, it is necessary to form a powder pneumatic transportation path that extends a required path, and such a powder pneumatic transportation path generally consists of a straight pipe that extends straight and a curved pipe. It is formed by appropriately connecting the bent pipes. Therefore, when the powder and granules attached to the air flow pass through the bend pipe, the powder and granules cannot necessarily flow smoothly along the curved transport path defined by the bend pipe, and there is considerable Powder particles having a certain amount of kinetic energy are caused to collide with the wall of the bend pipe. Therefore, wear progresses rapidly in a specific region of the bend pipe, and the bend pipe tends to be damaged (holes are formed) within a short period of time. In order to solve the above-mentioned problem regarding wear of the bent pipe, Japanese Utility Model Application Publication No. 55-136725 proposes a so-called split structure in which the bent pipe main body is constructed by connecting two members that can be detached from each other. A bend pipe is disclosed in which a plurality of round steel pieces are removably loaded in a region of a pipe wall of a bend pipe main body where powder particles collide. In such a bent pipe, the powder particles flowing through the bend pipe collide with the removably loaded round steel instead of the pipe wall of the bend pipe body, and therefore the wear caused by the collision of the powder particles does not occur in the bend pipe. It is generated not in the tube body but in a removably loaded round steel. When the wear of the round steel progresses, the two members that make up the bent pipe are separated, the worn round steel is replaced with a new round steel, and then the two members are interconnected. A bent pipe can be formed again. Therefore, by repeatedly replacing the round steel, damage to the bent pipe main body can be avoided and the bend pipe main body can be used for a long period of time. [Problems to be Solved by the Invention] According to the bent pipe disclosed in the above-mentioned Japanese Utility Model Application Publication No. 55-136725, the bent pipe main body can be used effectively for a long period of time, but (a) Since the bent pipe body has a split structure consisting of two members releasably connected, the initial manufacturing cost is relatively high. (b) When replacing worn round steel with new round steel, , it is necessary to perform disconnection and reconnection of two members constituting the bend pipe,
Therefore, a separate problem arises in that the operation of replacing the round bars is quite complicated. The present invention was made in view of these facts, and has a considerably lower initial manufacturing cost than the bent pipe disclosed in Utility Model Application No. 55-136725, and prevents wear of the bent pipe body. Even though it is quite easy to replace the parts used to prevent bending (the anti-wear rods that correspond to the above-mentioned round steel), wear on the bent pipe body is effectively prevented and the bend pipe body can be used effectively for a long period of time. The purpose is to provide a bend pipe that can be used. [Means for Solving the Problems] The solution of the present invention is to dispose a wear prevention rod that can be freely pulled out into the bend pipe body through an insertion opening formed in the bend pipe body, and the main part of the wear prevention rod is attached to the bend pipe body. It is located within the tube body, but its head is located outside the bent tube body. That is, according to the present invention, there is provided a bend pipe body that forms a curved powder air transport path, and a powder that is removably inserted into the bend pipe main body through an insertion opening formed in the wall of the bend pipe main body. The head of the wear prevention rod is located outside the bend pipe body, the main part of the wear prevention rod is located inside the bend pipe body, and the powder air A bend pipe characterized in that wear of the pipe wall of the bend pipe main body is prevented or suppressed by colliding powder and granules transported through the transport path with the main part of the wear prevention rod. provided. The bent tube body has an arcuate portion extending in an arc shape over an angular range of approximately 90 degrees, and the main portion of the wear prevention rod extends straight in a chord shape within the arcuate portion of the bent tube body. It is preferable to do so. [Function] In the bent pipe of the present invention, wear of the pipe wall of the bent pipe main body is prevented or suppressed by bringing the granular material flowing through the bend pipe into contact with the main portion of the wear prevention rod. The bend tube main body may be formed by simply forming an insertion port in a normal single-structure bend tube, and therefore the initial cost of the bend tube can be made sufficiently low. If the main part of the anti-wear rod is worn out, grasp the head located outside the bend pipe body and pull out the worn anti-wear rod from the bend pipe body, then insert a new anti-wear rod. The anti-wear rod can be replaced very quickly and easily by simply inserting it into the bend pipe body through the insertion opening. [Preferred Embodiment] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Referring to FIG. 1, the illustrated bent pipe includes a bent pipe main body 2 having a curved portion 4 and a straight portion 6. As shown in FIG. Curved portion 4 of bend pipe main body 2
is composed of an arc-shaped tube wall portion 8 extending in an arc shape over an angular range of θ (=90 degrees), and forms a curved transport path 10. The straight portion 6 of the bent pipe main body 2 is composed of a straight pipe wall portion 14 that extends straight a certain distance from the downstream end of the curved portion 4 when viewed in the flow direction shown by the arrow 12, and forms a straight transport path 16. There is. The cross-sectional shape of the bend pipe main body 2 may be circular (see also FIG. 2). The bent tube body 2 can be formed from any suitable material such as carbon steel. If desired, the inner surface of the bent tube body can be lined with a wear-resistant material such as a suitable ceramic. A disc-shaped end wall member 18 is fixed to the upstream end of the bend pipe main body 2. This end wall member 1
A circular opening 22 is formed in the center of the opening 8 .
On the other hand, an annular flange 26 is fixed to the upstream end of the straight pipe 20 which extends straight and has a relatively small diameter.
The annular flange 26 is connected to the end wall member 18 by suitable means such as fastening screws. In this way, the straight transport path 24 of relatively small diameter formed by the straight pipe 20 is connected to the curved transport path 10 formed by the curved portion 4 of the bent pipe body 2. A disc-shaped end wall member 28 is also fixed to the downstream end of the bend pipe main body 2, and a circular opening 32 is formed in the center of the end wall member 28. On the other hand, an annular flange 36 is fixed to the downstream end of the relatively small diameter straight pipe 30 that extends straight, and the annular flange 36 is connected to the end wall member 28 by an appropriate means such as a fastening screw. has been done.
In this way, the straight transport path 16 formed by the straight portion 6 of the bent pipe main body 2 is connected to the straight transport path 34 of relatively small diameter formed by the straight pipe 30. As shown in FIG. 1, transportation routes 2 are connected in sequence.
4, 10, 16 and 34 center lines 38, 40, 4
2 and 44 extend continuously, thus transport path 2
4, 10, 16 and 34 are advantageously arranged concentrically. The above straight pipes 20 and 30
Similarly to the bent pipe main body 2, it can also be formed from an appropriate material such as carbon steel. In the bend pipe constructed according to the invention, in addition to the bend pipe main body 2, a wear prevention rod 46 is also provided. This anti-wear rod 46
may be in the form of an elongated round bar, and may be formed from any suitable material such as steel. The illustrated wear prevention rod 46 has an elongated round bar shape, and has an enlarged head 46a formed at one end (upper end) thereof.
On the other hand, an insertion port is formed at the downstream end of the curved portion 4 in the bend pipe main body 2, and an insertion block 48 is fixed to the outer surface of the bend pipe main body 2 in correspondence with the insertion port. An insertion path communicating with the insertion port is formed in the insertion block 48, and a seal ring 50 is disposed within the insertion path. As clearly shown in FIG. 1, the anti-wear rod 46 is releasably inserted into the bend tube body 2 through the insertion passage and insertion opening.
The main part of the anti-wear rod 46 extends straight in the curved part 4 of the bent tube body 2 in a chordal manner. On the other hand, the enlarged head 46a of the wear prevention rod 46 is attached to the bend pipe main body 2.
be located outside. In the illustrated embodiment, a bar member 52 is attached to the insertion block 48 and the cover member 52 is attached to the anti-wear rod 4.
Covers the enlarged head 46a of No. 6. In the bent pipe as described above, an air flow accompanied by powder particles such as coal powder or abrasive powder enters the bent pipe main body 2 through the straight transport path 24 disposed on the upstream side. and a curved transport path 10 and a straight transport path 16 in the bent pipe main body 2
through which it then flows out into a straight conveyance channel 34 arranged downstream. The cross-sectional area of the curved transport path 10 within the bent pipe main body 2 is considerably larger than the cross-sectional area of the upstream straight transport path 24,
Therefore, when the air flow enters the curved transport path 10 from the straight transport path 24, its flow velocity is considerably reduced. Therefore, when the air flow flows through the curved transport path 10, the powder and granules attached thereto are also caused to flow within the curved transport path 10, but due to the inertial energy etc. of the powder and granules, As a result, the powder cannot flow sufficiently smoothly along the curved transport path 10. If the anti-wear rod 46 is not provided, the granular material that has entered the curved transport path 10 will flow with almost no change in its flow direction, and will flow to the right in FIG. It collides with the pipe wall located below with considerable kinetic energy. Therefore, if the anti-wear rod 46 is not provided, the pipe wall portion of the bent pipe main body 2 will be worn out and perforated within a short period of time. However, in the bent pipe constructed according to the present invention, the main part of the anti-wear rod 46 is made to extend within the curved transport path 10, and at least a large part of the powder or granules that enters the curved transport path 10 is The portion impinges on the main part of the anti-wear rod 46, and the direction of flow is changed by such impingement.
In this way, the collision of the granular material against the pipe wall portion of the bend pipe main body 2 is considerably prevented or suppressed, and therefore the wear of the pipe wall portion of the bend pipe main body 2 is effectively prevented or suppressed. If the main portion of the anti-wear rod 46 is considerably worn due to collision of powder and granules, the anti-wear rod 46 may be replaced with a new one. During such replacement, the cover member 52 is first removed from the insertion block 48 to expose the enlarged head 46a of the anti-wear rod 46. Next, the wear prevention rod 46 is pulled out from the bend pipe body 2 by grasping the exposed enlarged head 46a. Thereafter, a new anti-wear rod 46 can be inserted into the bent tube body 2 as required, and the cover member 52 can be mounted on the insertion block 48. Because of this, the replacement operation of the anti-wear rod 46 can be carried out significantly more quickly and easily. [Example and Comparative Example] Example A bent pipe having the form as shown in FIGS. 1 and 2 was made, and the bend pipe was
As shown in the figure, the upstream straight pipe and the downstream straight pipe were connected to form a conveyance path. Bend pipe body,
The upstream straight pipe and the downstream straight pipe were formed from carbon steel pipes for piping, and the wear prevention rods were formed from rolled steel round bars for general structural use. The dimensions of each part were as follows. Upstream straight transport path diameter d ₁ ...21.6mm Transport path inside the bent pipe body (curved transport path and straight transport path) diameter d ₂ ...105.3mm Radius of curvature of the central axis of the curved transport path r ₁ ...152.4
mm Length of the straight transport path of the bent pipe body l ₁ ...31.3mm Straight transport path on the downstream side d ₃ ...21.6mm Outer diameter of the main part of the wear prevention rod d ₄ ...18mm From the downstream end of the curved transport path to the insertion port Length l ₂ ...
…24mm Wear prevention rod inclination angle θ ₂ …45゜ From Showa Denko K.K. under the product name “Morundum A-
US mesh number 150 sold as ``43''
of alumina abrasive was conveyed through the transport channel in an air stream. In such transportation,
Alumina abrasive 60% for supply air 36Nm ³ /h
Kg/h (therefore the weight ratio of air flow to alumina abrasive was 1:1.3). The air flow velocity at the upstream end of the bent pipe body was 27.3 m/s. Both before the start of transport and after 212 hours of continuous transport, the thickness of various parts of the bent pipe body was measured using a "Type DM2" ultrasonic wall thickness meter (error accuracy: 0.1 mm) manufactured by Krautkramer GMBH in West Germany. It was then measured. The thickness measurement locations of the bent pipe body are as follows. Measurement points A, C, F, and I...The inside, both lateral sides, and outside in the bending direction at the position downstream of the upstream end of the bent pipe body at a bending angle of 45 degrees (F is the direction perpendicular to the plane of the paper in Fig. 1) On the rear side, I is the front side in the same direction) Measurement points B, E, and H...Both sides and outside in the bending direction at a position downstream of the upstream end of the bent pipe body at a bending angle of 67.5 degrees (E is the front side in the same direction) , H is the front side in the direction perpendicular to the plane of the paper) Measurement points D, G, and J...Both sides and outside in the bending direction at a position downstream of the upstream end of the bent pipe body at a bending angle of 22.5 degrees (G is the rear side in the direction perpendicular to the plane of the paper in FIG. 1, and J is the front side in the same direction.) The measurement results were as shown in Table 1 below. In addition, after 212 hours of continuous conveyance, we observed the wear condition of the wear prevention rod, as shown in Figure 3, and found that significant wear was observed in the vicinity of l ₃ (=60 mm) from the bottom end. . Comparative Example For comparison, an air stream entrained with powder was conveyed in the same manner as in the example except that no anti-wear rod was provided. In this comparative example, the bend pipe body was perforated 144 hours after the start of transportation, so transportation was stopped at this point. Therefore, the thickness measurements at various parts of the bent tube main body were performed before the start of transportation and after 144 hours had elapsed. The measurement results are shown in Table 1 below.

【table】

〔Effect of the invention〕

According to the bend pipe of the present invention, wear of the pipe wall of the bend pipe main body is sufficiently effectively prevented by the presence of the wear prevention rod, and therefore it can last for a long period of time as long as the wear prevention rod is replaced as appropriate. A bent pipe body can be used. There is no need to make the bend pipe body have a relatively expensive structure such as a split structure, and therefore the initial cost does not increase significantly. Replacing the anti-wear rod is accomplished significantly more quickly and easily by grasping its head, which is located outside the bend tube body, and pulling and inserting the anti-wear rod through the insertion opening in the bend tube body. can do.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a preferred embodiment of a bent pipe constructed according to the present invention. FIG. 2 is a sectional view taken along the line - in FIG. 1. FIG. 3 is a sectional view showing the wear state of the wear prevention rod itself in the embodiment. 2... Bend pipe main body, 4... Curved portion of bend pipe main body, 10... Curved transport path, 46... Wear prevention rod, 46a... Enlarged head of wear prevention rod.

Claims (1)

[Scope of Claims] 1. A bend tube body forming a curved powder air transport path, and a tube that is removably inserted into the bend tube body through an insertion opening formed in the wall of the bend tube body. a wear prevention rod, the head of the wear prevention rod is located outside the bend pipe body, the main part of the wear prevention rod is located inside the bend pipe body, and the powder and granule pneumatic transport A bend pipe characterized in that abrasion of the pipe wall of the bend pipe main body is prevented or suppressed by colliding powder and granules transported through the passage with the main portion of the anti-friction rod. 2. The bent pipe main body has an arcuate portion extending in an arc shape over an angular range of approximately 90 degrees, and the main portion of the wear prevention rod extends straight in a chord shape within the arcuate portion of the bend pipe main body. The bent pipe according to claim 1, wherein the bent pipe is