How to extend the life of a belt conveyor frame

Abstract

To prolong the life of a belt conveyor frame.SOLUTION: A belt conveyor frame 2, which is a truss structure, has at least: an upper chord 21; a lower chord 22 positioned below the upper chord 21; a vertical member 23 and a diagonal member 24 connecting the upper chord 21 and the lower chord 22; and a lateral member and a horizontal diagonal member that connect the upper chords 21 or the lower chords 22. A new vertical member 27 is attached below the vertical member 23 and on an extension line, a new lower chord 28 is attached to the new vertical member 27 in parallel to the lower chord 22, and the new lateral member connecting the new lower chords 28 is attached.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a method for extending the life of a belt conveyor frame. [Background technology]

[0002] For example, in steelworks, belt conveyors are used to transport various raw materials. The frame of the belt conveyor (belt conveyor frame) is a truss structure. A truss structure is composed of components such as upper chords, lower chords, vertical members, diagonal members, horizontal members, and horizontal diagonal members (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-178607 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a belt conveyor, raw materials are transported by a conveyor belt (belt) from the starting end to the terminal end of a belt conveyor frame (frame). However, some of the raw material may not fall off the belt at the end of the frame and may continue to adhere to the belt. As the raw material returns to the start of the frame, it may fall onto the lower chord or other components and accumulate as dust. The accumulation of dust may cause corrosion of the frame. Corroded frames need to be replaced (rebuilt), but because there are many conveyor belts with such frames on the steelworks site, it is necessary to extend the life of the frames as much as possible in order to reduce the cost of replacement.

[0005] The present invention has been made in consideration of the above points, and has an object to extend the life of a belt conveyor frame. [Means for solving the problem]

[0006] The present inventors have conducted extensive research and found that the above object can be achieved by adopting the following configuration, thereby completing the present invention.

[0007] That is, the present invention provides the following [1] to [8]. [1] A method for extending the life of a belt conveyor frame which is a truss structure, the belt conveyor frame having at least an upper chord, a lower chord located below the upper chord, vertical members and diagonal members connecting the upper chord and the lower chord, and horizontal members and horizontal diagonal members connecting the upper chords to each other or the lower chords to each other, the method comprising attaching new vertical members below and on the extension line of the vertical members, attaching new lower chords to the new vertical members parallel to the lower chords, and attaching new horizontal members connecting the new lower chords to each other. [2] A method for extending the life of a belt conveyor frame described in [1] above, in which an L-shaped cross-section material having an L-shaped cross-section and an L-shaped groove is used as at least one of the new lower chord members, and the L-shaped cross-section material is attached so that the opening of the L-shaped groove faces downward toward the belt conveyor frame. [3] A method for extending the life of a belt conveyor frame as described in [1] or [2] above, in which a hollow square pipe having a square cross section is used as at least one of the new lower chord members. [4] A method for extending the life of a belt conveyor frame described in any one of [1] to [3] above, comprising using a U-shaped cross-section material having a U-shaped cross-section and a U-shaped groove as at least one of the new lower chord members, and attaching a plate material to the U-shaped cross-section material to cover the U-shaped groove. [5] A method for extending the life of a belt conveyor frame described in any one of [1] to [4] above, in which a U-shaped cross-section material having a U-shaped cross-section and a U-shaped groove is used as at least one of the new lower chord members, and the U-shaped cross-section material is attached with the opening of the U-shaped groove facing toward the outside of the belt conveyor frame. [6] A method for extending the life of a belt conveyor frame described in any one of [1] to [5] above, comprising using an L-shaped cross-section material having an L-shaped cross-section and an L-shaped groove as at least one of the new lower chord members, and attaching a plate material to the L-shaped cross-section material to cover the L-shaped groove. [7] A method for extending the life of a belt conveyor frame described in any one of [1] to [6] above, wherein at least one of the new lower chord members is a triangular cross-section member. [8] A method for extending the life of a belt conveyor frame described in any one of [2] to [5] above, comprising attaching an umbrella member having a cross-sectional shape that protrudes upward onto at least one of the new lower chord members. Effect of the Invention

[0008] According to the present invention, the life of the belt conveyor frame can be extended. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a side view showing a schematic diagram of a belt conveyor. [Diagram 2] FIG. 2 is a bottom view showing a schematic diagram of the belt conveyor. [Diagram 3] 2 is a cross-sectional view taken along line XX in FIG. 1. [Figure 4] FIG. 11 is an enlarged cross-sectional view showing a portion of the belt conveyor frame to which the new member is attached. [Diagram 5] 5 is a cross-sectional view taken along line YY in FIG. 4. [Figure 6] FIG. 11 is a side view showing a schematic diagram of a belt conveyor having a new member attached to a belt conveyor frame. [Figure 7] FIG. 11 is a bottom view showing a schematic diagram of a belt conveyor with a new member attached to a belt conveyor frame. [Figure 8] FIG. 13 is a side view showing a modified example of the belt conveyor frame. [Figure 9] FIG. 13 is an enlarged cross-sectional view showing a part of the belt conveyor frame (variation A1) to which a new member is attached. [Figure 10]FIG. 13 is an enlarged cross-sectional view showing a part of the belt conveyor frame (variation A2) to which a new member is attached. [Figure 11] FIG. 13 is an enlarged cross-sectional view showing a portion of the belt conveyor frame (variation example A3) to which a new member is attached. [Figure 12] FIG. 13 is an enlarged cross-sectional view showing a portion of the belt conveyor frame (variation example A4) to which a new member is attached. [Figure 13] FIG. 13 is an enlarged cross-sectional view showing a part of the belt conveyor frame (variation example B1) to which a new member is attached. [Figure 14] FIG. 13 is an enlarged cross-sectional view showing a part of the belt conveyor frame (variation example B2) to which a new member is attached. [Figure 15] FIG. 13 is a cross-sectional view showing an enlarged portion of the belt conveyor frame (variation example B3) to which a new member is attached. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] <Basic structure of belt conveyor frame> First, the basic configuration of a belt conveyor frame 2, which is a truss structure, will be described with reference to Figs. 1 and 2. Fig. 1 is a side view showing a schematic diagram of a belt conveyor 1. Fig. 2 is a bottom view showing a schematic diagram of the belt conveyor 1. Figs. 1 and 2 show only main members constituting the belt conveyor 1. The belt conveyor 1 is mainly composed of a belt conveyor frame 2 and a conveyor belt 3, and is installed in, for example, a steelworks.

[0011] The belt conveyor frame 2 (hereinafter, simply referred to as "frame 2") is composed of linearly extending members (members long in one direction) such as upper chord members 21, lower chord members 22, vertical members 23, diagonal members 24, horizontal members 25, and horizontal diagonal members 26. These members include, for example, steel members with an L-shaped cross section.

[0012] The upper chord 21 and the lower chord 22 located below it are arranged parallel to each other. Adjacent upper chord members 21 (and adjacent lower chord members 22) are also arranged parallel to each other.

[0013] The vertical members 23 and the diagonal members 24 connect the upper chord member 21 to the lower chord member 22 located below it. The vertical members 23 are arranged perpendicular to the upper chord member 21 and the lower chord member 22, and the diagonal members 24 are arranged obliquely to the upper chord member 21 and the lower chord member 22.

[0014] The cross members 25 and the horizontal diagonal members 26 connect adjacent upper chord members 21 or adjacent lower chord members 22. In FIG. 2, the cross members 25 and the horizontal diagonal members 26 connecting the lower chord members 22 are shown. As shown in FIG. 2, the cross member 25 is arranged perpendicular to the lower chord member 22 (upper chord member 21), and the horizontal diagonal member 26 is arranged obliquely to the lower chord member 22 (upper chord member 21).

[0015] The conveyor belt 3 is a so-called endless belt, and is supported rotatably by a pair of pulleys 4 arranged on both ends of the frame 2. As the pulley 4 rotates, the conveyor belt 3 also rotates and is transported. In FIG. 1, the pulley 4 and the conveyor belt 3 rotate counterclockwise.

[0016] The transportation of the raw material 5 using the belt conveyor 1 will be described with reference to a part of the conveyor belt 3 (for convenience, referred to as "belt 3a"). First, at the starting end side of the frame 2 (the right side in FIG. 1), the raw material 5 is placed on one surface of the belt 3a, that is, surface A (indicated by the symbol A). The belt 3a with the raw material 5 on side A is transported on side B (indicated by the symbol B) opposite side A while being supported by the carrier roller 6, and is turned back at the end side (left side in FIG. 1) of the frame 2. When the belt 3a is turned back, the raw material 5 falls from side A of the belt 3a. Thus, the transport of the raw material 5 is completed. The belt 3 a that has been folded back at the end side of the frame 2 is then conveyed through the interior of a space 8 formed by the frame 2 while the A side of the belt 3 a is supported by a return roller 7 , and returns to the start side of the frame 2 .

[0017] Dust Incidentally, when the belt 3a is folded back at the end of the frame 2, a portion of the raw material 5 does not fall off completely from side A and continues to adhere thereto, and while the belt 3a is transported inside the space 8, it falls from side A as dust 9 (see FIG. 3).

[0018] Fig. 3 is a cross-sectional view taken along line XX in Fig. 1. However, in Fig. 3, the diagonal members 24, the horizontal diagonal members 26, the return rollers 7, etc. are omitted from the illustration. As the dust 9 repeatedly falls, as shown in Fig. 3, the dust 9 adheres to and accumulates on members such as the lower chord 22 that constitutes the frame 2. The accumulation of dust 9 causes corrosion of these members (and ultimately the frame 2).

[0019] If the corrosion of the frame 2 progresses, various problems will arise in operation. Therefore, the corroded frame 2 needs to be renewed (rebuilt). However, since there are many belt conveyors 1 having such frames 2, it is desirable to extend the life of the frames 2 without updating them in order to reduce the cost of updating.

[0020] 4 to 7, a method for extending the life of the frame 2 according to the present embodiment (also referred to as the present life extension method) will be described below. The present life extension method is, in outline, a method for attaching new members (such as a new lower chord member 28 described later) to the frame 2.

[0021] <How to extend the life of a belt conveyor frame> Fig. 4 is an enlarged cross-sectional view of a part of the belt conveyor frame 2 to which the new member is attached. Fig. 5 is a cross-sectional view taken along line YY in Fig. 4.

[0022] In this life extension method, first, the vertical member 23 is extended downward. Specifically, a new vertical member 27 is attached below and on the extension line of the existing vertical member 23. Next, a new bottom chord 28 is attached to the new vertical member 27 in parallel with the existing bottom chord 22.

[0023] Furthermore, in this life extension method, a new horizontal member 29 is installed to connect adjacent new lower chord members 28. The new horizontal member 29 is installed in parallel to the existing horizontal member 25, for example.

[0024] In addition, in this life extension method, a new horizontal diagonal member 30 may be installed to connect adjacent new lower chord members 28. The new horizontal diagonal member 30 is installed, for example, parallel to the existing horizontal diagonal member 26.

[0025] In addition, the term "extension" is a concept that includes a range (error range) that can be regarded as being substantially an extension in the technical field to which the present invention belongs. Similarly, the term "parallel" is a concept that includes a range (error range) within which it is acceptable to essentially regard something as being parallel in the technical field to which the present invention pertains.

[0026] As the new members (new vertical member 27, new lower chord member 28, new horizontal member 29 and new horizontal diagonal member 30), it is preferable to use members that extend in a straight line and are long in one direction (for example, steel members with an L-shaped cross section), similar to the existing members such as the lower chord member 22 and vertical member 23. The new member is attached to the existing member (or another new member) by, for example, welding. The welding method is not particularly limited, and any conventionally known welding method can be appropriately adopted. It is preferable to use both the existing and new members in standard lengths, as this makes it possible to minimize the number of welding points.

[0027] 4, in this life extension method, a plate-shaped reinforcing member 31 may be used to strengthen the connection between an existing member (e.g., vertical member 23) and a new member (e.g., new vertical member 27). The material of the reinforcing member 31 is preferably the same as that of the existing member and the new member.

[0028] Fig. 6 is a side view showing a schematic diagram of the belt conveyor 1 with a new member attached to the belt conveyor frame 2. Fig. 7 is a bottom view showing a schematic diagram of the belt conveyor 1 with a new member attached to the belt conveyor frame 2. New diagonal members (not shown) may be attached to the new vertical members 27 and the new lower chord members 28, similar to the existing diagonal members 24. In this case, it is preferable to attach them via battens (not shown) so that a bending moment is not generated in the frame 2.

[0029] FIG. 8 is a side view diagrammatically illustrating a modified example of the belt conveyor frame 2. As shown in FIG. 8, the end of the frame 2 may be supported from below by a support 10. In this case, it is difficult to extend the vertical member 23 downward at the end of the frame 2. In other words, it is difficult to attach a new vertical member 27 below the existing vertical member 23. Therefore, in this case, for example, as shown in Fig. 8, the new lower chord 28 is shaped so that it gradually rises from the center of the frame 2 toward the end. Then, new cross members 29 and new horizontal diagonal members 30 are attached to the new lower chord 28 of this shape. This makes it possible to attach new members even at the end of the frame 2 while avoiding the supports 10.

[0030] As described above, according to this life extension method, new members (new vertical member 27, new lower chord member 28, new horizontal member 29 and new horizontal diagonal member 30) are attached to frame 2, thereby reinforcing frame 2. For example, even if the lower chord 22, which is an existing member of frame 2, is corroded, the strength of the lower chord 22 can be restored by reinforcing it with a new member, and ultimately the overall strength of frame 2 can be restored, thereby extending the life of frame 2.

[0031] At the stage of attaching new components to the frame 2, the existing lower chord 22 may be corroded and may not have sufficient strength. Therefore, in this life extension method, in addition to the new lower chord 28, a new cross member 29 and a new horizontal diagonal member 30 are installed. This ensures strength that can withstand, for example, wind loads and earthquake loads.

[0032] In this life extension method, when attaching a new member to the frame 2 using the above-mentioned procedure, for example, scaffolding is assembled below the frame 2, and workers stand on this scaffolding to carry out welding work.

[0033] However, the procedure for attaching the new member is not limited to the procedure described above. For example, the new members may be welded together at a low level in advance and assembled. In this case, the assembled new members are hoisted up to the frame 2, and a worker gets on the aerial work vehicle and performs further necessary welding work (welding the assembled new members to the frame 2). This eliminates the cost and construction time required for erecting scaffolding.

[0034] Regardless of the work procedure, in this life extension method, the work of attaching new components to frame 2 is performed outside of frame 2, so there is no need to shut down belt conveyor 1 for an extended period of time, and the life of frame 2 can be extended without reducing production.

[0035] Incidentally, as a method for extending the life of the frame 2, there is a method for replacing each member constituting the frame 2 with a new member (for example, see Patent Document 1). However, when this method is adopted, it is necessary to stop the operation of the belt conveyor 1 to carry out the work, because the section modulus of the frame 2 as a truss structure decreases. In some cases, it may be necessary to stop the operation of the belt conveyor 1 for a long period of time, resulting in reduced production. In contrast, as described above, according to the present life extension method, it is possible to extend the life of the frame 2 without requiring the belt conveyor 1 to be shut down for a long period of time and without reducing production.

[0036] <Modification of new lower chord> Next, a method for suppressing the accumulation of dust 9 on the new lower chord 28 will be described. Generally, as shown in Figs. 9 to 15, the shape and / or mounting method of at least one of the new lower chord members 28, which are new members, is devised.

[0037] Variation A1 FIG. 9 is an enlarged cross-sectional view showing a part of the belt conveyor frame 2 (variation A1) to which the new member is attached. 4 and 5, in the modification A1, L-shaped cross-section members having an L-shaped cross section are used as the lower chord member 22 and the new lower chord member 28. Therefore, the lower chord member 22 has an L-shaped groove 41, and similarly, the new lower chord member 28 also has an L-shaped groove 42. The opening of the L-shaped groove 41 of the lower chord member 22 faces upward of the frame 2. For this reason, dust 9 is likely to accumulate in the L-shaped groove 41 of the lower chord member 22. In contrast, the opening of the L-shaped groove 42 of the new lower chord 28 faces downward of the frame 2. For this reason, the area of ​​the new lower chord 28 that comes into contact with the dust 9 is reduced compared to the lower chord 22.

[0038] In addition, in all of the modified examples described below, an L-shaped cross-section material is used as the lower chord 22, and the opening of the L-shaped groove 41 faces upward of the frame 2, similar to the modified example A1.

[0039] Variation A2 FIG. 10 is an enlarged cross-sectional view showing a part of the belt conveyor frame 2 (variation A2) to which the new member is attached. In the modified example A2, a hollow square pipe with a square cross section is used as the new lower chord member 28. In this case as well, the area of ​​the new lower chord member 28 that comes into contact with the dust 9 is reduced compared to the lower chord member 22.

[0040] Variation A3 FIG. 11 is an enlarged cross-sectional view showing a part of the belt conveyor frame 2 (variation A3) to which the new member is attached. In the modified example A3, a U-shaped cross-section member having a U-shaped cross section is used as the new lower chord member 28. Therefore, the new lower chord member 28 has a U-shaped groove 43. The new lower chord 28, which is a U-shaped cross-section member, is arranged so that the opening of the U-shaped gutter 43 faces the inside (the right side in FIG. 11) of the frame 2. If this is left as it is, there is a possibility that dust 9 will easily enter the inside of the U-shaped gutter 43. However, in the modified example A3, a plate material 32 that closes the U-shaped groove 43 is attached to the new lower chord member 28. This prevents the dust 9 from entering the inside of the U-shaped groove 43. The material of the plate material 32 is not particularly limited, and may be resin, etc. The method of attaching the plate material 32 to the new lower chord member 28 is also not particularly limited, and any conventionally known method may be appropriately adopted. In variant A3 as well, the area of ​​contact between the new lower chord 28 and the dust 9 is smaller than that of the lower chord 22.

[0041] Variation A4 FIG. 12 is an enlarged cross-sectional view showing a part of the belt conveyor frame 2 (variation A4) to which the new member is attached. In variant A4, as in variant A3 (Figure 11), a U-shaped cross-section member having a U-shaped groove 43 is used as the new lower chord member 28. However, in the modified example A4, the new lower chord 28, which is a U-shaped cross-section member, is arranged so that the opening of the U-shaped gutter 43 faces the outside (the left side in FIG. 12) of the frame 2. For this reason, dust 9 is less likely to enter the inside of the U-shaped gutter 43. In variant A4 as well, the area of ​​contact between the new lower chord 28 and the dust 9 is reduced compared to that of the lower chord 22.

[0042] As described above, in the modified examples A1 to A4 (FIGS. 9 to 12), the area of ​​the new lower chord member 28 that comes into contact with the dust 9 is reduced compared to the lower chord member 22. For this reason, the new lower chord 28 can suppress the rate of corrosion (thinning) due to the accumulation of dust 9 more than the lower chord 22, and can delay deterioration.

[0043] Variation B1 FIG. 13 is an enlarged cross-sectional view showing a part of the belt conveyor frame 2 (variation example B1) to which the new member is attached. In modification B1, similar to the frame 2 shown in Figures 4 and 5, L-shaped cross-section members are used as the lower chord 22 and the new lower chord 28, and the orientation is also the same as in Figures 4 and 5. That is, the opening of the L-shaped groove 42 of the new lower chord 28 faces upward in the frame 2. If this continues, there is a possibility that dust 9 will easily enter the inside of the L-shaped groove 42. However, in the modified example B1, a plate material 33 that closes the L-shaped groove 42 is attached to the new lower chord member 28. This prevents the dust 9 from entering the inside of the L-shaped groove 42. The material of the plate material 33 is not particularly limited, and may be resin, etc. The method of attaching the plate material 33 to the new lower chord member 28 is also not particularly limited, and any conventionally known method may be appropriately adopted. In variant B1, the plate material 33 is arranged at an angle, thereby preventing the accumulation of dust 9 on the new lower chord material 28.

[0044] Variation B2 FIG. 14 is an enlarged cross-sectional view showing a part of the belt conveyor frame 2 (variation example B2) to which the new member is attached. In variant example B2, a triangular cross-section material with a triangular cross-section is used as the new lower chord material 28. That is, in variant B2, the new lower chord 28 itself has an inclined surface, which prevents the accumulation of dust 9 on the new lower chord 28, as in variant B1.

[0045] Variations B3 to B6 FIG. 15 is an enlarged cross-sectional view showing a part of the belt conveyor frame 2 (variation example B3) to which the new member is attached. In Modifications B3 to B6, an umbrella member 34 having a cross-sectional shape that protrudes upward is attached to the upper surface of the new lower chord member 28 of Modifications A1 to A4 (FIGS. 9 to 12) described above, respectively. FIG. 15 representatively shows the state in which a cap member 34 is attached to the new lower chord member 28 of modified example A1 (FIG. 9). The material of the umbrella member 34 is not particularly limited, and may be resin, etc. The method of attaching the umbrella member 34 to the new lower chord member 28 is also not particularly limited, and any conventionally known method may be appropriately adopted. In modified examples B3 to B6, the umbrella member 34 arranged on the upper surface of the new lower chord member 28 has an inclined surface, which prevents the accumulation of dust 9 on the new lower chord member 28.

[0046] As described above, in the modified examples B1 to B6 (FIGS. 13 to 15), accumulation of dust 9 on the new lower chord member 28 is prevented. For this reason, the new lower chord 28 in variants B1 to B6 has a very small area of ​​contact with dust 9, and compared to the above-mentioned variants A1 to A4 (Figures 9 to 12), the rate of corrosion (thinning) due to the accumulation of dust 9 can be more effectively suppressed, and deterioration can be further delayed. EXAMPLES

[0047] The present invention will be specifically described below with reference to examples, although the present invention is not limited to the examples described below.

[0048] Comparative Examples 1-2 and Invention Example 1 In a belt conveyor similar to that described based on Figs. 1 and 2, a belt conveyor frame (frame) in which corrosion had progressed was renewed or its life was extended as follows.

[0049] In Comparative Example 1, the entire frame was renewed. That is, in Comparative Example 1, a new frame was newly manufactured and the corroded frame was replaced. At this time, the operation of the corroded belt conveyor was stopped before replacing it with the newly manufactured frame.

[0050] In Comparative Example 2, the frame was partially renewed. That is, in Comparative Example 2, only the bottom chord of the frame where corrosion had progressed was replaced with a new bottom chord. In Comparative Example 2, the operation of the belt conveyor was also stopped when the bottom chord was replaced.

[0051] In Example 1, the life of the frame was extended without replacing it. That is, in Example 1, a new member was attached to the corroded frame based on the above-mentioned life extension method. In Example 1, the operation of the belt conveyor was hardly stopped when the new member was attached.

[0052] The evaluation results of Comparative Examples 1 and 2 and Invention Example 1 are shown in the following Table 1. The symbols "x", "△", "◯" and "◎" in the following Table 1 indicate more favorable evaluation results from front to back.

[0053] [Table 1]

[0054] As shown in Table 1 above, in Comparative Example 1, in which the frame was completely renewed, the life of the renewed frame was better than those in Comparative Example 2 and Invention Example 1 (life: ⊚). However, in Comparative Example 1, since a new frame had to be newly produced, the cost was greater than in Comparative Example 2 and Invention Example 1 (cost: ×). In addition, because the operation of the belt conveyor had to be stopped during the upgrade, the upgrade took a long time (time: △). Specifically, it took 144 hours.

[0055] Furthermore, as shown in Table 1 above, in Comparative Example 2 in which the frame was partially updated, the cost required for updating was able to be reduced more than in Comparative Example 1 (cost: ◯). However, as in Comparative Example 1, the operation of the belt conveyor was stopped during the renewal, so the renewal took a long time (time: △). Specifically, it took 144 hours, as in Comparative Example 1.

[0056] In contrast, as shown in Table 1 above, in Example 1, the belt conveyor operation stoppage was minimal when attaching new members to the frame, and the time required to extend the life of the frame was very short at 40 hours (time: ◯). In addition, compared to Comparative Example 1, in which a new frame was newly manufactured, costs were reduced (cost: ◯). For these reasons, the overall evaluation of Example 1 was given a better result than Comparative Examples 1 and 2, giving it a rating of "Excellent."

[0057] Comparative Example 3 and Invention Example 2 For a belt conveyor frame (frame) similar to that described based on Figures 1 and 2, the frame before the installation of new parts was set as Comparative Example 3, and the frame to which new parts were installed based on the above-mentioned life extension method was set as Invention Example 2. The frame has a distance of 1000 mm from the upper cross member (the cross member connecting the upper chords) to the lower cross member (the cross member connecting the lower chords), and in Example 2 of the invention, the new lower chord was attached 350 mm below the existing lower chord. The section modulus (unit: cm) of the frames of Comparative Example 3 and Example 2 was 3 The results are shown in Table 2 below.

[0058] [Table 2]

[0059] As shown in Table 2 above, when the section modulus of the frame of Comparative Example 3 is taken as 1, the section modulus of the frame of Invention Example 2 could be increased by 1.38 times. That is, in Example 2, the strength of the frame as a truss structure could be improved by attaching the new member to the existing member.

[0060] <Examples 3 to 5> A new member was attached to a belt conveyor frame (frame) similar to that described with reference to Figs. 1 and 2, based on the present life extension method described above. In this case, an L-shaped cross-section member was used as the new lower chord member, and the L-shaped groove was attached facing upward toward the frame (see Figs. 4 and 5), which was taken as Example 3 of the invention. In the case where an L-shaped cross-section material was used as the new lower chord and its L-shaped groove was attached facing downward toward the frame, that is, variant example A1 (see Figure 9), was designated as Example 4 of the invention. In the case where an L-shaped cross-section material was used as the new lower chord, its L-shaped groove was attached facing downward toward the frame, and a cap material was also attached, that is, variant example B3 (see Figure 15), was designated as example 5 of the invention.

[0061] First, in Examples 3 and 4, the thickness of the new lower chord was reduced by 2 mm due to dust accumulation. In this case, in Example 3 (see Figs. 4 and 5), the section modulus of the new lower chord was reduced by 31% from the original value. In contrast, in Example 4 (Variation A1, see Figure 9), the section modulus of the new lower chord member only decreased by 8%. In Example 4, the area of ​​the new lower chord member in contact with dust was reduced more than in Example 3, which is thought to have slowed the rate of thickness reduction and suppressed the decrease in the section modulus. Similar effects can be expected in Variations A2 to A4 (Figures 10 to 12).

[0062] Next, for Invention Examples 3 and 5, dust was deposited on the top surface of the new bottom chord. At this time, in Example 3 (see Figs. 4 and 5), dust accumulated over the entire length of the new lower chord. In contrast, in Example 5 (Modification B3, see Figure 15), a cap member was placed on the top surface of the new bottom chord, so dust did not accumulate on the top surface of the new bottom chord (dust accumulated only on the top surface of the new cross member). This is expected to suppress deterioration of the new bottom chord. The same effect can be expected in Modifications B4 to B6, which also use cap members. [Explanation of symbols]

[0063] 1: belt conveyor, 2: belt conveyor frame (frame), 3, 3a: conveyor belt (belt), 4: pulley, 5: raw material, 6: carrier roller, 7: return roller, 8: space, 9: dust, 10: support, 21: upper chord, 22: lower chord, 23: vertical member, 24: diagonal member, 25: horizontal member, 26: horizontal diagonal member, 27: new vertical member, 28: new lower chord, 29: new horizontal member, 30: new horizontal diagonal member, 31: reinforcement member, 32: plate member, 33: plate member, 34: umbrella member, 41: L-shaped groove, 42: L-shaped groove, 43: U-shaped groove

Claims

1. A method for extending the life of a belt conveyor frame which is a truss structure, comprising: The belt conveyor frame has at least an upper chord member, a lower chord member located below the upper chord member, vertical members and diagonal members connecting the upper chord member and the lower chord member, and horizontal members and horizontal diagonal members connecting the upper chord members to each other or the lower chord members to each other, Attach a new vertical member below and on the extension line of the vertical member, A new lower chord is attached to the new vertical member parallel to the lower chord, Attach new cross members to connect the new lower chord members together, At least one of the new lower chord members is an L-shaped section member having an L-shaped cross section and an L-shaped groove; The method for extending the life of a belt conveyor frame includes attaching the L-shaped cross-section member with the opening of the L-shaped groove facing downward toward the belt conveyor frame.

2. A method for extending the life of a belt conveyor frame which is a truss structure, comprising: The belt conveyor frame has at least an upper chord member, a lower chord member located below the upper chord member, vertical members and diagonal members connecting the upper chord member and the lower chord member, and horizontal members and horizontal diagonal members connecting the upper chord members to each other or the lower chord members to each other, Attach a new vertical member below and on the extension line of the vertical member, A new lower chord is attached to the new vertical member parallel to the lower chord, Attach new cross members to connect the new lower chord members together, A method for extending the life of a belt conveyor frame, comprising using a hollow square pipe having a square cross section as at least one of the new lower chord members.

3. A method for extending the life of a belt conveyor frame which is a truss structure, comprising: The belt conveyor frame has at least an upper chord member, a lower chord member located below the upper chord member, vertical members and diagonal members connecting the upper chord member and the lower chord member, and horizontal members and horizontal diagonal members connecting the upper chord members to each other or the lower chord members to each other, Attach a new vertical member below and on the extension line of the vertical member, A new lower chord is attached to the new vertical member parallel to the lower chord, Attach new cross members to connect the new lower chord members together, At least one of the new lower chord members is a U-shaped cross-section member having a U-shaped groove; A method for extending the life of a belt conveyor frame by attaching a plate material that blocks the U-shaped groove to the U-shaped cross-section material.

4. A method for extending the life of a belt conveyor frame which is a truss structure, comprising: The belt conveyor frame has at least an upper chord member, a lower chord member located below the upper chord member, vertical members and diagonal members connecting the upper chord member and the lower chord member, and horizontal members and horizontal diagonal members connecting the upper chord members to each other or the lower chord members to each other, Attach a new vertical member below and on the extension line of the vertical member, A new lower chord is attached to the new vertical member parallel to the lower chord, Attach new cross members to connect the new lower chord members together, At least one of the new lower chord members is a U-shaped cross-section member having a U-shaped groove; The method for extending the life of a belt conveyor frame includes attaching the U-shaped cross-section member with the opening of the U-shaped groove facing toward the outside of the belt conveyor frame.

5. A method for extending the life of a belt conveyor frame which is a truss structure, comprising: The belt conveyor frame has at least an upper chord member, a lower chord member located below the upper chord member, vertical members and diagonal members connecting the upper chord member and the lower chord member, and horizontal members and horizontal diagonal members connecting the upper chord members to each other or the lower chord members to each other, Attach a new vertical member below and on the extension line of the vertical member, A new lower chord is attached to the new vertical member parallel to the lower chord, Attach new cross members to connect the new lower chord members together, At least one of the new lower chord members is an L-shaped section member having an L-shaped cross section and an L-shaped groove; A method for extending the life of a belt conveyor frame by attaching a plate material that blocks the L-shaped groove to the L-shaped cross-section material.

6. A method for extending the life of a belt conveyor frame which is a truss structure, comprising: The belt conveyor frame has at least an upper chord member, a lower chord member located below the upper chord member, vertical members and diagonal members connecting the upper chord member and the lower chord member, and horizontal members and horizontal diagonal members connecting the upper chord members to each other or the lower chord members to each other, Attach a new vertical member below and on the extension line of the vertical member, A new lower chord is attached to the new vertical member parallel to the lower chord, Attach new cross members to connect the new lower chord members together, A method for extending the life of a belt conveyor frame, comprising using a triangular cross-section material having a triangular cross-section as at least one of the new lower chord members.

7. The method for extending the life of a belt conveyor frame according to any one of claims 1 to 4, further comprising attaching an umbrella member having a cross-sectional shape protruding upward onto at least one of the new lower chord members.

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