Granule conveyance method by vertical circulation bucket conveyor

Abstract

To prevent dropping of granules from a gap between a bucket and an outlet of a conveyor casing side during conveying of low-density granules on a vertical circulation bucket conveyor.CONSTITUTION: Granules are vertically conveyed between an inlet and an outlet provided in the casing of a bucket conveyor on a vertical circulation bucket conveyor on which a plurality of buckets are fixed to a chain to be vertically circulated. A plate projected from the outlet to the bucket side is detachably attached to the outlet so that each bucket can intermittently come into contact with the plate. Thus, a gap between the outlet and the bucket can be reduced, and the granules accumulated on the plate are shaken off to the outlet side by shocks of contact between the bucket and the plate.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] This invention relates to a method for transporting powdery or granular materials using a vertical circulating bucket conveyor, for example, a method for transporting granular materials made of gypsum dihydrate powder obtained by crushing waste gypsum boards. [Background technology]

[0002] The inventors have been working on recovering gypsum from waste gypsum board (Patent Document 1). In the method developed by the inventors, the waste gypsum board is crushed and sieved to separate the paper pieces from the gypsum lumps. Metallic foreign matter is then removed using a magnetic separator, and the gypsum powder and paper pieces are separated by secondary crushing. If necessary, heavy foreign matter such as gravel is removed using an air table or the like. The resulting gypsum dihydrate is calcined to produce hemihydrate and / or anhydrous type III gypsum powder and particles. The calcined gypsum is mixed with gypsum slurry, and gypsum dihydrate particles are precipitated in a crystallization tank. The gypsum dihydrate powder is filtered out, and the filtrate is returned to the crystallization tank or the like. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-79303 Summary of the Invention [Problem to be solved by the invention]

[0004] In the process up to mixing with gypsum slurry, gypsum powder may be transported to a high position due to the layout of the equipment. The powder is composed of gypsum dihydrate, which is an aggregate of thin needle-like crystals in the gypsum board with a high porosity, resulting in an extremely low specific gravity. In addition, if the waste gypsum board gets wet in the rain, the powder may become damp and become more adhesive.

[0005] This gypsum powder is raised by the buckets of a vertical circulating bucket conveyor, which rotates at the discharge port and discharges the powder. Because the gypsum powder derived from waste gypsum board has a low specific gravity, centrifugal force barely acts on the powder, and the powder does not move sufficiently horizontally. Instead, it falls through the gap between the front edge of the bucket and the conveyor casing, accumulating at the bottom of the casing. Furthermore, because gypsum powder has low fluidity and is adhesive, it can adhere to the casing at the discharge port and pile up. As a result, the following gypsum powder cannot pass through the discharge port and falls through the gap, accumulating at the bottom of the conveyor casing.

[0006] The gypsum powder that accumulates at the bottom of the casing is scraped off with a bucket and transported. However, if the gypsum powder accumulates at the bottom of the casing, the powder must be circulated between the discharge port and the bottom of the casing, making transportation inefficient. In extreme cases, a large amount of powder accumulates at the bottom of the casing, causing the conveyor to stop.

[0007] This problem is not limited to the discharge port, but is also present at the inlet for gypsum powder. Because the force that moves the powder horizontally is weak, the powder tends to fall through the gap between the inlet and the bucket. Furthermore, when gypsum powder accumulates at the inlet, the following powder loses its horizontal speed as it climbs over the accumulated powder, and falls through the gap to the bottom of the casing.

[0008] The object of this invention is to prevent low-specific-gravity powder, such as gypsum powder derived from waste gypsum board, from falling through the gap between the bucket and the discharge outlet on the casing side of the conveyor when transporting the powder using a vertical circulating bucket conveyor. [Means for solving the problem]

[0009] This invention relates to a method for vertically transporting powder or granular material between an inlet and an outlet provided in a casing of a vertically circulating bucket conveyor that vertically circulates a plurality of buckets fixed to a chain, the method comprising: A plate protruding from the discharge port toward the bucket is detachably attached to at least the discharge port so that the bucket intermittently contacts the plate, The gap between the discharge port and the bucket is reduced, The impact of contact between the bucket and the plate causes the powder and granular material accumulated on the plate to be knocked off towards the discharge outlet.

[0010] In this invention, the gap with the bucket can be shortened by the plate. Also, powder accumulated on the plate is knocked off by the impact of contact with the bucket, so that the accumulated powder does not interfere with the movement of subsequent powder. If the plate is made of a material softer than the bucket, damage to the bucket can be prevented. The discharge port itself does not come into contact with the bucket, and the plate is detachable, so if the plate is damaged, it can be replaced, for example.

[0011] Preferably, plates are attached to both the discharge port and the inlet, so that the powder and granular material can be smoothly moved from the inlet to the bucket not only at the discharge port but also at the inlet.

[0012] Preferably, the plate is made of fluororesin, which provides it with the toughness to withstand contact with the bucket, the elasticity to easily deform when it comes into contact with the bucket, and low friction to prevent powder and granular material from accumulating on the plate.

[0013] Preferably, the plate is attached so that the length of its projection toward the bucket side is adjustable, thereby making it possible to adjust the frequency of contact between the plate and the bucket and to adjust the gap between the plate and the bucket. [Brief explanation of the drawings]

[0014] [Figure 1] Vertical cross-sectional view of the vertical circulating bucket conveyor used in the embodiment [Figure 2] Vertical cross section of the main part of the vertical circulating bucket conveyor in Figure 1 [Figure 3] Diagram showing the plate positioning mechanism DETAILED DESCRIPTION OF THE INVENTION

[0015] Examples for carrying out the present invention are shown below. The scope of the present invention should be determined based on the claims, taking into account the description in the specification and well-known techniques in this field, and in accordance with the understanding of those skilled in the art. The scope of the present invention is not limited by the examples. [Example]

[0016] Figures 1 to 3 show a vertically circulating bucket conveyor 2 according to an embodiment and a method for transporting powder and granular material according to the embodiment. 4 denotes multiple buckets, made of metal or plastic, attached to chain 6 and circulating vertically within cylindrical circulation space 7. 8 and 9 denote sprockets rotated by a motor (not shown) to vertically circulate buckets 4. 10 denotes a casing for conveyor 2, made of metal, for example, through inlet 12, which feeds powder and granular material derived from waste gypsum board into bucket 4. Inlet 12 is equipped with, for example, a screw conveyor or rotary valve (not shown). Bucket 4 drops the powder and granular material into outlet 14 of the casing. 13 and 15 denote conveying surfaces consisting of the bottom surfaces of inlet 12 and outlet 14, and the powder and granular material slides along conveying surfaces 13 and 15.

[0017] The fallen gypsum dihydrate granular material 16 accumulates at the bottom 17 of the casing 10 of the conveyor 2 and is scraped off by the bucket 4. The object of the present invention is to reduce the amount of fallen granular material 16. The granular material to be treated may be calcined gypsum derived from waste gypsum board, or other granular material with a low specific gravity, such as grain flour or kaolin.

[0018] Plates 20, 20 protruding into the circulation space 7 are detachably attached to the tips of the conveying surfaces 13, 15 of the discharge port 14 and the inlet 12. The plates 20, 20 are preferably elastic enough to deform upon contact with the bucket 4, allowing the bucket 4 to move vertically, and tough enough to withstand repeated force from the bucket. Furthermore, the plates 20, 20 are preferably made to allow the powder and granules to slide relative to the plates 20, i.e., to prevent the powder and granules from adhering to the plates 20, and preferably have a low surface friction coefficient. A preferred material for the plates 20 is fluororesin, which combines elasticity, toughness, and low friction. However, other materials, such as ultra-high molecular weight polyethylene (UHMN-PE) and rigid polyvinyl chloride (PVC), are also acceptable. Plates 20 are not required to be provided at both the discharge port 14 and the inlet 12; they are provided at least at the discharge port 14.

[0019] Plate 20 protrudes into circulation space 7 so as to come into contact with bucket 4 intermittently, for example, so as to come into contact with bucket 4 approximately once every 10 to several hundred revolutions of bucket 4 between sprockets 8 and 9. The horizontal length by which plate 20 protrudes from outlet 14 or inlet 12 is designated as t, and the horizontal gap between plate 20 and the leading edge of bucket 4 is designated as d, as shown schematically in Figures 2 and 3. Note that because chain 6 vibrates, the trajectory of the tip of bucket 4 is not constant, and gap d is also not constant.

[0020] Because the plate 20 protrudes toward the circulation space 7, only a small amount of the powder and granules discharged from the bucket 4 falls through the gap d. As shown in Figure 2, powder and granules 21 such as gypsum dihydrate accumulate in a mound at the discharge port 14, blocking the movement of subsequent powder and granules. However, because the plate 20 intermittently comes into contact with the bucket 4, the impact causes the mounded powder and granules to collapse and be discharged. As a result, the powder and granules are discharged smoothly from the discharge port 14.

[0021] The function of the plate 20 is the same at both the discharge port 14 and the input port 12, but at the input port 12, the powder can be actively pushed out by a screw conveyor or the like. At the discharge port 14, the force moving the powder toward the discharge port 14 side is weak, so the plate 20 is very important.

[0022] Although the plate 20 repeatedly comes into contact with the bucket 4, it has toughness and elasticity, so it can be used continuously for, for example, about three months. It is preferable that the plates 20, 20 are attached to the discharge port 14 and the inlet 12 so that the protruding length t can be adjusted freely. For example, as shown in Figure 3, a long hole 22 is provided in the plate 20 or the discharge port 14 and the inlet 12, and the protruding length t of the plate 20 is adjusted by a screw 23 or the like. The mechanism for adjusting the length t is arbitrary.

[0023] The embodiment has the following effects. 1) The gap d between the inlet 12 and the bucket 4 and the discharge outlet 14 is narrowed by the plate 20, thereby reducing the amount of powder or granules that are racked through the gap d. 2) Powder and granular materials accumulated on the plate 20 are brushed off by intermittent contact between the bucket 4 and the plate 20, thereby preventing the powder and granular materials from accumulating on the plate 20 and interfering with the movement of subsequent powder and granular materials. 3) When the plate 20 comes into contact with the bucket 4, the plate 20 deforms to allow the bucket 4 to pass, so that the bucket 4 is less likely to be damaged. 4) The plate 20 is softer than the bucket 4 and does not damage the bucket 4. Also, if the plate 20 is damaged, it can be replaced. 5) If the plate 20 is made of fluororesin, it will have toughness, elasticity and low friction. 6) The mounting position of the plate 20 is variable, and the protruding length t of the plate 20 can be adjusted. [Explanation of symbols]

[0024] 2 Vertical Circulation Bucket Conveyor 4 buckets 6 Chain 7 Circulation Space 8,9 sprocket 10 Casing 12 Inlet 14 Outlet 13,15 Conveying surface 16 Gypsum powder 17 Bottom 20 plates 21 Gypsum powder 22 long hole 23 screws d-gap t protruding length

Claims

1. A method for vertically conveying powder or granular material between an inlet and an outlet provided in a casing of a vertically circulating bucket conveyor in which a plurality of buckets are fixed to a chain and circulated vertically, comprising: A plate protruding from the discharge port toward the bucket is detachably attached to at least the discharge port so that the bucket intermittently contacts the plate, The gap between the discharge port and the bucket is reduced, The impact of contact between the bucket and the plate knocks the powder accumulated on the plate down towards the discharge port. A method for transporting powder and granular materials using a vertical circulating bucket conveyor, characterized by:

2. 2. The method for transporting powdery or granular material by a vertical circulating bucket conveyor according to claim 1, wherein said plates are attached to both said discharge port and said input port.

3. 3. The method for transporting powdery or granular material by a vertical circulating bucket conveyor according to claim 1 or 2, wherein the plates are made of fluororesin.

4. 3. A method for transporting powdery or granular materials by a vertical circulating bucket conveyor according to claim 1 or 2, wherein the length of the plate projecting toward the bucket side is adjustable.

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