Improved long return roller and long return roller group including the same

Abstract

To provide a long return roller group capable of: improving durability to intense contact of a long return roller central portion with a belt, thereby preventing body cracking of the central portion; facilitating replacement work without becoming too heavy with a low cost even if a body cracking prevention measure is applied to the long return roller; and preventing the body cracking of the central portion.SOLUTION: There are provided: an improved long return roller 2 having a rubber ceramic sheet 5 of an 8 mm thickness and a 200 mm width fixed around the central portion in the longitudinal direction of a roller 4; and a long return roller group having three or more improved long return rollers 2 arranged on the lower surface side of a return side belt.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an improved long return roller for a belt conveyor that has been provided with anti-wear measures, and to a group of long return rollers that are arranged including the improved long return roller. [Background technology]

[0002] In steelworks, belt conveyors are widely used to transport raw materials for pig iron production, but as powder accumulates on the return belt, it is necessary to clean it with a belt cleaner. However, it is impossible to completely remove this dust, and the belt cleaner itself deteriorates over time, reducing its cleaning function. As a result, the return belt may come into contact with the return roller while the dust is still attached to it, and the weight of the belt conveyor on the return roller may cause wear, leading to cracks. To address this issue, the following prior art has been disclosed. For example, Patent Document 1 (Japanese Utility Model Application Laid-Open Publication No. 54-93990) describes that when transporting sticky substances such as pitch and tar on a belt conveyor, by covering the return roller that comes into contact with the belt surface with a rubber-like elastic body having a thickness of 1 mm or more, adhesion of the transported substance can be prevented, enabling long-term operation (see in particular lines 5-10 on page 4 and Figure 2 of the specification).

[0003] Furthermore, Patent Document 2 (JP Patent Publication No. 9-77234) describes that when a ceramic ring (4) is used in a disc roller (3) for a return roller, by inserting a rubber plate (5) with a thickness of 1 mm to 50 mm as a shock absorbing material between the core metal (1) and the ceramic ring (4), the roller is more durable than a conventional metal roller, has no performance problems, and is effective in terms of economy and safety (see especially paragraph 0009 and Figure 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 54-93990 [Patent Document 2] Japanese Patent Application Publication No. 9-77234 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the belt conveyor described in Patent Document 1 is intended to prevent adhesion of sticky substances, and is not suitable for abrasive substances such as iron ore. Furthermore, the disc roller for the return roller described in Patent Document 2 has a problem in that it has a complicated structure and is costly. Furthermore, the return belts of belt conveyors that transport iron ore and coke are covered with powdery material that cannot be completely removed by cleaners. This material comes into contact with the return rollers, causing wear and tear on the surface of the return rollers, which can then break. In particular, belt conveyors with a belt width of 1400 mm or more have a heavy belt weight (27 kg / m for 1400 mm, 33 kg / m for 1600 mm), and the load on the long return rollers is large, which causes concentrated contact between the belt and the center of the long return roller, often resulting in core cracks (more than 90% of defects are caused by core cracks in the center). In order to solve these problems, the first objective of this invention is to improve durability against concentrated contact between the belt and the center of the long return roller and prevent central cracking.The second objective is to provide an improved long return roller that is inexpensive and easy to replace even when measures to prevent cracking are taken on the long return roller without becoming too heavy. A third object of the present invention is to provide a group of long return rollers that can reduce concentrated contact between the belt and the center of the return rollers and prevent center body cracking. [Means for solving the problem]

[0006] The invention according to claim 1 to solve the above problem is: In a belt conveyor having a belt width of 1400 mm or more, an improved long return roller is provided, which comprises a rotating shaft portion and a roller portion disposed on the underside of a return belt, and supports the underside of the return belt, A wear-resistant sheet having a thickness of 5 to 15 mm is fixed over a width of 150 to 500 mm around the periphery of the center in the longitudinal direction of the roller portion.

[0007] The invention according to claim 2 is the improved long return roller according to claim 1, The abrasion-resistant sheet is characterized by being a rubber ceramic sheet.

[0008] The invention according to claim 3 is characterized in that three or more improved long return rollers according to the invention according to claim 1 or 2 and regular long return rollers to which no wear-resistant sheet is fixed are alternately arranged at predetermined intervals on the underside of the return belt. The long return roller group is characterized by: [Effects of the Invention]

[0009] The improved long return roller of the invention according to claims 1 and 2 has a wear-resistant sheet (a rubber ceramic sheet in claim 2) 5 to 15 mm thick fixed around the longitudinal center of the roller section over a width of 150 to 500 mm, thereby improving durability against concentrated contact between the belt and the center of the improved long return roller and preventing cracking of the center body. Furthermore, compared with a long return roller in which a wear-resistant sheet is fixed to the entire periphery of the roller portion, the weight is lighter, making replacement easier, and the amount of wear-resistant sheet used is reduced, making it possible to provide an improved long return roller with measures to prevent body cracking at a low cost.

[0010] The long return roller group of the invention according to claim 3 is composed of three or more improved long return rollers of the invention according to claim 1 or 2, which have been provided with anti-wear measures, and regular long return rollers, which do not have wear-resistant sheets fixed to the roller portions, arranged alternately at predetermined intervals on the underside of the return belt, thereby mitigating concentrated contact between the belt and the center of the return rollers and preventing center body cracking.In addition, since the number of improved long return rollers of the invention according to claim 1 or 2 can be reduced, a long return roller group that can prevent center body cracking can be provided more inexpensively. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a side view of a belt conveyor according to a first embodiment to which an improved long return roller is applied. [Figure 2] A view of a standard long return roller from the front. [Figure 3] Front view of the improved long return roller. [Figure 4] FIG. 1 is an explanatory diagram of a roller stand used in manufacturing an improved long return roller. [Figure 5] FIG. 10 is a side view of a belt conveyor according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, the present invention will be described in detail with reference to examples. [Example]

[0013] The belt conveyor according to the first embodiment shown in FIG. 1 includes a drive pulley 11 rotated by a motor (not shown), a driven pulley 12 that rotates following the drive pulley 11, a drive-side snap pulley 13 disposed below the drive pulley 11, a tension pulley 14 disposed below the driven pulley 12, a drive-side bend pulley 15 disposed above the tension pulley 14 on the drive pulley 11 side (on the left side in FIG. 1) and supporting the underside of the return-side belt 18b, and a drive-side bend pulley 15 disposed above the tension pulley 14 on the driven pulley 12 side (on the left side in FIG. 1). 1) and is provided with a driven bend pulley 16 that supports the underside of the return side belt 18b and a driven snap pulley 17 that is provided below and near the driven pulley 12, and further includes a belt 18 (width 1600 mm) wound around a drive pulley 11, a drive snap pulley 13, a drive bend pulley 15, a weight pulley 14, the driven bend pulley 16, the driven snap pulley 17 and the driven pulley 12, and eight improved long return rollers 2 that support the underside of the return side belt 18b. The drive bend pulley 15, weight pulley 14, and driven bend pulley 16 form a tension section 19, and the belt 18 can be kept in a tensioned state at all times by a constant force exerted by the weight of the weight pulley 14. The belt conveyor according to the first embodiment conveys an object (not shown), such as raw materials for ironmaking, placed on the upper surface of the conveying belt 18a in the conveying direction (the direction of the right arrow in FIG. 1) by rotating the drive pulley 11. At this time, the return belt 18b moves in the return direction (the direction of the left arrow in FIG. 1) opposite to the conveying direction.

[0014] As shown in FIG. 2, a normal long return roller 1 is made up of a rotating shaft portion 3 (length 1730 mm, diameter 30 mm) and a roller portion 4 (length 1630 mm, diameter 300 mm). The improved long return roller 2, which is a key component of the present invention, has a rotating shaft 3 and roller portion 4 configured in the same manner as the normal long return roller 1, and as shown in Figure 3, an 8 mm thick rubber ceramic sheet 5 is fixed over a width of 200 mm around the longitudinal center of the roller portion 4. In the belt conveyor according to Example 1 shown in Figure 1, seven improved long return rollers 2 are arranged at regular intervals between the drive-side snap pulley 13 and the drive-side bend pulley 15 to form an improved long return roller group. In addition, one improved long return roller 2 is arranged between the driven-side snap pulley 17 and the driven pulley 12.

[0015] FIG. 4 is an explanatory diagram of a roller stand 6 used when fixing a rubber ceramic sheet 5 to the roller portion 4 of the improved long return roller 2. The improved long return roller 2 is manufactured by the following procedure. (Step 1) Prepare a regular long return roller 1. (Step 2) The periphery of the center in the longitudinal direction of the roller part 4 is sanded over a width of about 220 mm using an electric sander (not shown). (Step 3) Prepare a rubber ceramic sheet 5 having a width of 200 mm, a length of 992 mm, and a thickness of 8 mm, and polish the back side, after which rubber cement is applied. (Step 4) As shown in Figure 4, the rotating shaft 3 of the normal long return roller 1 is placed on the support part 7 of the roller stand 6. Then, while the normal long return roller 1 is rotating, rubber cement 8 is applied to the center of the roller part 4 with a 200 mm long brush. (Step 5) The normal long return roller 1 coated with the rubber cement 8 is left on the roller stand 6 for 20 minutes. (Step 6) The rubber ceramic sheet 5 to which rubber glue was applied in step 3 is wrapped around the part of the normal long return roller 1 to which rubber glue 8 was applied that was left for 20 minutes in step 5, and pressure is applied from the periphery by hitting the surface side of the rubber ceramic sheet 5 with a hammer, for example.

[0016] After manufacturing eight improved long return rollers 2 using steps 1 to 6 above, seven improved long return rollers 2 are arranged at regular intervals between the drive side snap pulley 13 and the drive side bend pulley 15, and one improved long return roller 2 is arranged between the driven side snap pulley 17 and the driven pulley 12, thereby completing the belt conveyor of Example 1 shown in Figure 1. The completed belt conveyor was operated on a trial basis for a year and a half, and the degree of wear of the rubber ceramic sheet 5 fixed to the roller part 4 was checked, and it was found to be about 30%. Based on this result, the service life of the improved long return roller 2 is estimated to be about four years. [Example]

[0017] FIG. 5 is a side view of a belt conveyor according to the second embodiment. The belt conveyor according to Example 2 differs only in that, instead of the improved long return roller group consisting of seven improved long return rollers 2 arranged between the drive side snap pulley 13 and the drive side bend pulley 15 in the belt conveyor according to Example 1, a long return roller group consisting of three normal long return rollers 1 and four improved long return rollers 2. Therefore, the configuration other than the long return roller group will be described in Figure 5 using the same numbers as in Figures 1 to 3.

[0018] The long return roller group according to Example 2 is arranged between the drive side snap pulley 13 and the drive side bend pulley 15, just like the improved long return roller group according to Example 1, but of the seven improved long return rollers 2 in Example 1, the second, fourth, and sixth improved long return rollers 2 from the drive side snap pulley 13 are replaced with regular long return rollers 1. That is, in Example 2, the long return roller group is constituted by alternately arranging four improved long return rollers 2 and three regular long return rollers 1 at regular intervals. The reason for this configuration is that evaluation tests were conducted on various long return roller groups that combined regular long return rollers 1 and improved long return rollers 2, and it was found that the regular long return rollers 1 on both sides of the improved long return rollers 2 had less wear in the center.

[0019] Modifications of the first and second embodiments are listed below. (1) The belt width of the belt conveyors according to Examples 1 and 2 was 1600 mm, but if the belt width is 1400 mm or more, the effect of preventing central body cracking can be obtained. When the belt width is 1200mm, wear due to contact with the belt is observed near both ends of the roller and near the center, but head breakage is more common near both ends than center body cracks near the center.Also, when the belt width is 1050mm or 750mm, wear due to contact with the belt is observed near both ends of the roller, and most head breakage occurs near both ends. (2) In the improved long return roller 2 in Examples 1 and 2, an 8 mm thick rubber ceramic sheet 5 was fixed over a width of 200 mm around the center of the longitudinal direction of the roller portion 4. However, if the width is not limited to 200 mm but is in the range of 150 to 500 mm, and the thickness is not limited to 8 mm but is in the range of 5 to 15 mm, it is possible to obtain the effects of improving durability against concentrated contact at the center of the belt 18 and the improved long return roller 2 and reducing the amount of rubber ceramic sheet 5 used. However, considering economy and ease of installation, it is better to keep the width in the range of 150 to 300 mm and the thickness in the range of 5 to 10 mm. Moreover, instead of the rubber ceramic sheet 5, a wear-resistant sheet made of other wear-resistant rubber or wear-resistant resin such as ultra-high molecular weight polyethylene, POM (polyacetal), or PTFE (fluororesin) may be fixed. (3) In the belt conveyor according to Example 1, seven improved long return rollers 2 are alternately arranged at regular intervals between the drive side snap pulley 13 and the drive side bend pulley 15 to form an improved long return roller group, and in the belt conveyor according to Example 2, four improved long return rollers 2 and three regular long return rollers 1 are alternately arranged at regular intervals between the drive side snap pulley 13 and the drive side bend pulley 15 to form a long return roller group, but they may be arranged at any predetermined interval, not limited to a regular interval. (4) In the belt conveyors of Examples 1 and 2, the normal long return roller 1 and the improved long return roller 2 are arranged along a straight line between the drive side snap pulley 13 and the drive side bend pulley 15, and the belt 18 is hung in a straight line, but they may also be arranged along a curve. When arranging them along a curve, placing the improved long return roller 2 near the inflection point of the curve and arranging the normal long return roller 1 or the improved long return roller 2 before and after it at short intervals (approximately 1 to 2 m intervals) can alleviate concentrated contact between the belt 18 and the center of the roller section 4, thereby improving the effect of preventing center body cracking. [Explanation of symbols]

[0020] 1 Normal long return roller 2 Improved long return roller 3 Rotating shaft 4 Roller part 5 Rubber ceramic sheet 6 Roller stand 7 Support part 8 Rubber cement 11 driving pulley 12 driven pulley 13 driving side snap pulley 14 Tension pulley 15 Drive side bend pulley 16 Driven bend pulley 17 Driven snap pulley 18 Belt 18a Conveyor belt 18b Return belt

Claims

1. In a belt conveyor having a belt width of 1400 mm or more, an improved long return roller is provided, which includes a rotating shaft portion and a roller portion disposed on the underside of a return belt, and supports the underside of the return belt, A wear-resistant sheet having a thickness of 5 to 15 mm is fixed around the longitudinal center of the roller portion over a width of 150 to 500 mm. Improved long return roller characterized by:

2. The wear-resistant sheet is a rubber ceramic sheet.

10. The improved long return roller of claim 1.

3. The improved long return rollers according to the invention of claim 1 or 2 and the normal long return rollers with no wear-resistant sheet fixed to the roller portion are alternately arranged at a predetermined interval on the underside of the return belt in three or more units. A group of long return rollers characterized by:

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