JP7474140B2 - Storage Facilities - Google Patents

Description

The present invention relates to a storage facility equipped with a reclaimer.

In storage facilities that store coal, minerals, etc., stored materials are removed by a reclaimer. Among reclaimers, scraper-type reclaimers scrape out stored materials by rotating multiple scrapers attached to a boom. Scraper-type reclaimers are further classified into full portal type and semi-portal type depending on the type of portal that supports the boom.

In a full-portal reclaimer, the portal has a roughly semicircular shape and is formed to span between one widthwise end of the storage area and the other widthwise end of the storage area. On the other hand, a semi-portal reclaimer has a structure that is half of a full-portal reclaimer. Specifically, in a semi-portal reclaimer, the portal has a roughly quarter-circular shape and is formed to span between one widthwise end of the storage area and the upper surface of a retaining wall provided in the storage area (see Patent Document 1).

JP 2019-59605 A

As mentioned above, the semi-portal reclaimer is formed to span between one end of the storage area in the width direction and the top surface of the retaining wall installed in the storage area. In other words, when constructing a storage facility equipped with a semi-portal reclaimer, the installation of a retaining wall was essential. This retaining wall is made of concrete and is therefore very heavy. For this reason, it is necessary to reinforce the ground around the retaining wall by driving in more piles than in other areas, which tends to result in high civil engineering construction costs.

The present invention aims to provide a storage facility equipped with a semi-portal type reclaimer that can reduce civil engineering construction costs.

A storage facility according to one aspect of the present invention comprises a storage platform on which stored items are loaded, a central body disposed in the widthwise center of the storage platform and extending in the longitudinal direction, a first semi-portal reclaimer that travels in the longitudinal direction in a first area on one side of the central body in the widthwise direction to dispense the stored items loaded on the storage platform, and a second semi-portal reclaimer that travels in the longitudinal direction in a second area on the other side of the central body in the widthwise direction to dispense the stored items loaded on the storage platform, the first reclaimer comprising a first boom that drives a first scraper in a circular motion to dispense the stored items, The first reclaimer has a first portal that supports the first boom, the second reclaimer has a second boom that drives a second scraper in a circular motion to dispense stored materials, and a second portal that supports the second boom, and the central body has a beam section that extends over the entire travel range of the first reclaimer and the second reclaimer and supports the tip portion of the first portal and the tip portion of the second portal so that they can travel, and a plurality of pillar sections that extend vertically to support the beam section and are spaced apart from each other in the longitudinal direction, and an opening is formed between adjacent pillar sections.

The above storage facility has a central body with an opening formed therein, instead of a conventional retaining wall. Therefore, with the above storage facility, the weight of the structures in the storage area can be reduced, thereby reducing civil engineering construction costs. Moreover, the above storage facility maintains the function of supporting the first and second portals that the retaining wall had.

The present invention provides a storage facility equipped with a semi-portal reclaimer that can reduce civil engineering construction costs.

FIG. 1 is a cross-sectional view of the storage facility in the width direction. FIG. 2 is a schematic perspective view of the central body and its surroundings. FIG. 3 is a block diagram of the control system of the storage facility. FIG. 4 is a flow diagram of the contact avoidance process. FIG. 5 is a diagram showing a contact type distance detector. FIG. 6 is a widthwise cross-sectional view of a storage facility according to a modified example.

<Overall structure of storage facility>
Hereinafter, an embodiment of the present invention will be described. First, the overall structure of a storage facility 100 according to this embodiment will be described. Fig. 1 is a widthwise cross-sectional view of the storage facility 100. Hereinafter, the left-right direction of the paper surface of Fig. 1 will be referred to as the "width direction", and the direction perpendicular to the paper surface of Fig. 1 will be referred to as the "longitudinal direction".

As shown in FIG. 1, the storage facility 100 according to this embodiment includes a storage table 10, a central body 20, a first reclaimer 30, a second reclaimer 40, a first discharge conveyor 50, a second discharge conveyor 60, and a distance detector 70. Below, these components will be described in order.

The storage platform 10 is a structure on which stored materials 101 such as coal and minerals are loaded. Here, the central body 20 described below serves as the boundary, with one side of the central body 20 of the storage facility 100 (the left side of the paper in FIG. 1) being the first area 11, and the other side (the right side of the paper in FIG. 1) being the second area 12. The storage platform 10 has a first bottom surface 13 located in the first area 11, and a second bottom surface 14 located in the second area 12.

The first bottom surface 13 and the second bottom surface 14 are inclined so that they become higher as they go outward in the width direction. Furthermore, the outer end portions of the first bottom surface 13 and the second bottom surface 14 in the width direction protrude outward in the width direction and are located above the floor surface. However, the first bottom surface 13 and the second bottom surface 14 may be horizontal. Furthermore, the outer end portions of the first bottom surface 13 and the second bottom surface 14 in the width direction may be located at the same height as the floor surface.

The central body 20 is a structure provided in the center of the width of the storage platform 10 and extends in the longitudinal direction. FIG. 2 is a schematic perspective view of the central body 20 and its surroundings. As shown in FIG. 2, the central body 20 has a beam portion 21 and a number of pillar portions 22. The beam portion 21 is located in the upper part of the central body 20 and extends over the entire travel range of the first reclaimer 30 and the second reclaimer 40 described below. Each pillar portion 22 extends vertically and supports the beam portion 21.

Furthermore, each column section 22 is provided at a distance from each other in the longitudinal direction, and an opening 23 is formed between adjacent column sections 22. However, in a part of the central body 20, an opening 23 may not be formed between adjacent column sections 22, and the space between adjacent column sections 22 may be formed like a wall. In other words, an opening 23 may not be formed in all spaces between adjacent column sections 22.

In addition, the central body 20 has supports 24 formed on both sides of each column 22 in the width direction to increase the strength against forces in the width direction or to partition the space. However, the supports 24 may be formed only on one side of the column 22 in the width direction, or may be formed only on some of the column parts 22. The supports 24 may be formed in a wall shape or in a frame shape. Furthermore, the central body 20 supports the roof 26 of the building 25 via the building columns 27. In this way, in this embodiment, the central body 20 supports the roof 26 at the center of the width direction of the building 25, so that the strength required for the building 25 can be reduced. Therefore, the building 25 can be made lighter and the construction cost can be reduced. In addition, the central body 20 can support the loading conveyor 28 that loads the stored items 101 to the storage platform 10 via the building columns 27.

The first reclaimer 30 is a device that travels longitudinally in the first area 11 and dispenses the stored material 101 loaded on the storage platform 10. The first reclaimer 30 in this embodiment is a scraper-type reclaimer and is classified as a semi-portal type. As shown in FIG. 1, the first reclaimer 30 has a first boom 31 and a first portal 32.

The first boom 31 has a first drive unit 34 consisting of a huge chain that goes around the first arm 33, and a number of first scrapers 35 that are plate-shaped and provided on the first drive unit 34. When the first drive unit 34 goes around, the first scraper 35 goes around accordingly. This allows the first scraper 35 to dispense the stored items 101 loaded on the storage platform 10. Specifically, when the first scraper 35 is driven to go around in the normal direction (clockwise on the paper in FIG. 1), the stored items 101 on the first bottom surface 13 are sent outward in the width direction and dispensed onto the first discharge conveyor 50.

However, the first scraper 35 may be driven to rotate in a reverse direction (counterclockwise on the paper in FIG. 1) opposite to the forward direction, to send the stored items 101 on the first bottom surface 13 onto the second bottom surface 14. In this case, the second reclaimer 40 dispenses the stored items 101 sent onto the second bottom surface 14 onto the second discharge conveyor 60.

The first portal 32 is a part that supports the first boom 31. The base end portion of the first portal 32 is fixed to the first traveling device 36. This first traveling device 36 has wheels 37, is located widthwise outward of the storage table 10, and travels in the longitudinal direction. The first portal 32 is also shaped like a quadrant, and its tip portion is supported on the beam portion 21 of the central body 20 so as to be able to travel.

Furthermore, the base end portion of the first boom 31 described above is rotatably supported by the first portal 32 (or the first traveling device 36), and the portion of the first boom 31 that is closer to the tip than the central portion is supported by the first portal 32 via a first hoisting wire 38. The length of this first hoisting wire 38 is adjusted by a first winch 39 (see FIG. 3). Therefore, by adjusting the length of the first hoisting wire 38 by the first winch 39, the elevation angle of the first boom 31 changes, and the first boom 31 can be positioned appropriately relative to the stored item 101.

The second reclaimer 40 is a device that travels longitudinally in the second area 12 and dispenses the stored material 101 loaded on the storage platform 10. The second reclaimer 40 of this embodiment is a scraper-type reclaimer and is classified as a semi-portal type. As shown in FIG. 1, the second reclaimer 40 has a second boom 41 and a second portal 42.

The second boom 41 has a second drive unit 44 consisting of a huge chain that goes around the second arm 43, and a number of second scrapers 45 that are provided on the second drive unit 44 and have a plate-like shape. When the second drive unit 44 goes around, the second scraper 45 goes around accordingly. This allows the second scraper 45 to dispense the stored items 101 loaded on the storage platform 10. Specifically, when the second scraper 45 is driven to go around in the forward direction (counterclockwise on the paper in FIG. 1), the stored items 101 on the second bottom surface 14 are sent outward in the width direction and dispensed onto the second discharge conveyor 60.

However, the second scraper 45 may be driven to rotate in a reverse direction (clockwise on the paper in FIG. 1) opposite to the forward direction, to send the stored items 101 on the second bottom surface 14 onto the first bottom surface 13. In this case, the first reclaimer 30 dispenses the stored items 101 sent onto the first bottom surface 13 onto the first discharge conveyor 50.

The second portal 42 is a part that supports the second boom 41. The base end portion of the second portal 42 is fixed to the second traveling device 46. This second traveling device 46 has wheels 47, is located widthwise outward of the storage table 10, and travels in the longitudinal direction. The second portal 42 is also shaped like a quadrant, and its tip portion is supported on the beam portion 21 of the central body 20 so as to be able to travel.

Furthermore, the base end portion of the second boom 41 described above is rotatably supported by the second portal 42 (or the second traveling device 46), and the portion of the second boom 41 that is closer to the tip than the central portion is supported by the second portal 42 via a second hanging wire 48. The length of this second hanging wire 48 is adjusted by a second winch 49 (see FIG. 3). Therefore, by adjusting the length of the second hanging wire 48 by the second winch 49, the elevation angle of the second boom 41 changes, and the second boom 41 can be positioned appropriately relative to the stored item 101.

The first discharge conveyor 50 is a device that discharges the stored items 101 dispensed by the first reclaimer 30. The first discharge conveyor 50 is located below the outer end portion in the width direction on the first bottom surface 13 side of the storage table 10, and extends in the longitudinal direction. The first discharge conveyor 50 receives the stored items 101 that have been scraped up by the first boom 31 of the first reclaimer 30 and dropped from the storage table 10, and transports the received stored items 101 in the longitudinal direction.

The second discharge conveyor 60 is a device that discharges the stored items 101 dispensed by the second reclaimer 40. The second discharge conveyor 60 is located below the outer end portion in the width direction on the second bottom surface 14 side of the storage table 10, and extends in the longitudinal direction. The second discharge conveyor 60 receives the stored items 101 that have been scraped up by the second boom 41 of the second reclaimer 40 and dropped from the storage table 10, and transports the received stored items 101 in the longitudinal direction.

The distance detector 70 is a device provided to avoid contact between the first boom 31 and the second boom 41, and detects the "boom distance" which is the distance between the first boom 31 and the second boom 41 when viewed in the longitudinal direction. In this embodiment, the distance detector 70 is provided at the tip of the second boom 41, but it may be provided at the first boom 31, or at both the first boom 31 and the second boom 41.

The distance detector 70 of this embodiment has an emitter 71 that emits ultrasonic waves or light, and detects the boom distance based on the ultrasonic waves or light emitted from the emitter 71 and reflected back by the second boom 41. The emitter 71 of the distance detector 70 is configured to rotate or swing around a rotation axis 72 that extends in the longitudinal direction. As the emitter 71 continues to rotate or swing, the boom distance can be reliably detected even if the relative positions of the first boom 31 and the second boom 41 change when viewed in the longitudinal direction.

<Control system configuration>
Next, the configuration of the control system of the storage facility 100 will be described. Fig. 3 is a block diagram of the configuration of the control system of the storage facility 100. The storage facility 100 is equipped with a control device 80 that controls the first reclaimer 30 and the second reclaimer 40. The control device 80 has a processor, a volatile memory, a non-volatile memory, an I/O interface, and the like.

The control device 80 is electrically connected to a first encoder 81 that detects the rotation angle of the wheels 37 of the first traveling device 36, a second encoder 82 that detects the rotation angle of the wheels 47 of the second traveling device 46, and the distance detector 70. The control device 80 can obtain the rotation angle of the wheels 37 from the first encoder 81 and calculate the longitudinal position of the first reclaimer 30 based on the obtained rotation angle. Similarly, the control device 80 can obtain the rotation angle of the wheels 47 from the second encoder 82 and calculate the longitudinal position of the second reclaimer 40 based on the obtained rotation angle. The control device 80 can also obtain the boom-to-boom distance from the distance detector 70.

The control device 80 is further electrically connected to the first traveling device 36, the second traveling device 46, the first winch 39, and the second winch 49. The control device 80 transmits control signals to these devices to control each device. In this embodiment, the control device 80 stores a contact avoidance program (described later) and various data in a non-volatile memory, and the processor performs calculations using the volatile memory based on the contact avoidance program.

<Contact Avoidance Program>
Next, a description will be given of the contact avoidance program executed by the control device 80. Fig. 4 is a flowchart of the contact avoidance program. The process shown in Fig. 4 is executed by the control device 80.

When the contact avoidance program is started, the control device 80 calculates the longitudinal distance between the first reclaimer 30 and the second reclaimer 40 (hereinafter referred to as the "reclaimer distance") (step S1). The reclaimer distance can be calculated based on the rotation angle of the wheel 37 obtained from the first encoder 81 and the rotation angle of the wheel 47 obtained from the second encoder 82.

The control device 80 then determines whether the reclaimer distance calculated in step S1 is smaller (closer) than a predetermined contact distance (step S2). Here, the "contact distance" refers to the upper limit of the reclaimer distance at which the first boom 31 and the second boom 41 may come into contact depending on the angular positions of the first boom 31 and the second boom 41. In other words, if the first reclaimer 30 and the second reclaimer 40 come closer than the contact distance, there is a possibility that the first boom 31 and the second boom 41 may come into contact.

If the control device 80 determines that the reclaimer distance is not smaller (larger) than the contact distance (NO in step S2), the process returns to step S1 and repeats each step. On the other hand, if the control device 80 determines that the reclaimer distance is smaller than the contact distance (YES in step S2), the process proceeds to step S3 and performs contact avoidance processing to avoid contact between the first boom 31 and the second boom 41. In this embodiment, steps S3 and onwards correspond to the contact avoidance processing.

When the process proceeds to step S3, the control device 80 acquires the boom distance. The boom distance can be acquired from the distance detector 70.

Next, the control device 80 determines whether the boom distance obtained in step S3 is smaller than the danger distance (step S4). If the boom distance is smaller than the danger distance, there is a high possibility that the first boom 31 and the second boom 41 will come into contact.

If the control device 80 determines that the boom distance is not smaller (larger) than the danger distance (NO in step S4), the process returns to step S1 and repeats each step. On the other hand, if the control device 80 determines that the boom distance is smaller than the danger distance (YES in step S2), the movement of the first boom 31 and the second boom 41 is stopped (step S5). This prevents contact between the first boom 31 and the second boom 41.

However, in step S5, contact between the first boom 31 and the second boom 41 may be avoided by a method other than the above-mentioned method. For example, the first boom 31 and the second boom 41 may be moved in a direction that increases the distance between the booms. Also, for example, the control device 80 may send a control signal to an alarm device (not shown) to activate the alarm device.

The above is the flow of the contact avoidance program of this embodiment. Note that in this embodiment, the boom distance is detected by a distance detector 70 using ultrasonic waves or light, and contact avoidance processing is performed based on the detected boom distance, but contact avoidance processing may be performed by another method. For example, the elevation/depression angles of the first boom 31 and the second boom 41 may be detected by an angle sensor, the boom distance may be calculated based on the detected elevation/depression angles, and contact avoidance processing may be performed based on the calculated boom distance.

Although the distance detector 70 in this embodiment is a non-contact type that detects the boom distance using ultrasonic waves or light, the distance detector 70 may be a contact type. For example, the distance detector 70 may have a lever 73 and a limit switch 74 as shown in FIG. 5. If this distance detector 70 is provided at the tip of the first boom 31 and the second boom 41, the lever 73 comes into contact with the first scraper 35 or the second scraper 45, activating the limit switch 74, thereby detecting the boom distance. Then, contact avoidance processing may be performed based on the boom distance detected by this distance detector 70.

<Modification>
Fig. 6 is a widthwise cross-sectional view of a storage facility 100 according to a modified example. In the embodiment described above, contact between the first boom 31 and the second boom 41 is avoided by the contact avoidance program executed by the control device 80, but contact between the first boom 31 and the second boom 41 may be avoided by forming the first boom 31 and the second boom 41 to have a length such that they do not come into contact with each other, as shown in Fig. 6.

In this case, however, there will be an area of the storage table 10 that neither the first boom 31 nor the second boom 41 can reach. Therefore, the storage facility 100 according to the modified example has a specially designed shape for the storage table 10. Specifically, the storage facility 100 according to the modified example has a first bottom surface 13 that corresponds to the range (movable range) that the first boom 31 can reach, a second bottom surface 14 that corresponds to the range (movable range) that the second boom 41 can reach, and a boundary surface 15 that is located between the first bottom surface 13 and the second bottom surface 14.

The edge of the first bottom surface 13 on the boundary surface 15 side and the edge of the second bottom surface 14 on the boundary surface 15 side are at different heights. In this modified example, the edge of the first bottom surface 13 on the boundary surface 15 side is higher than the edge of the second bottom surface 14 on the boundary surface 15 side. Furthermore, the boundary surface 15 is inclined at an angle greater than the angle of repose of the stored goods 101. Therefore, the stored goods 101 cannot remain at the boundary surface 15 that neither the first boom 31 nor the second boom 41 can reach. Therefore, according to the storage facility 100 of the modified example, the first boom 31 and the second boom 41 do not come into contact with each other, and the stored goods 101 do not remain in an area that the first boom 31 and the second boom 41 cannot reach.

<Action and effect>
As described above, the storage facility according to the embodiment includes a storage platform on which stored items are loaded, a central body that is provided in the widthwise center of the storage platform and extends in the longitudinal direction, a first semi-portal reclaimer that travels in the longitudinal direction in a first area on one side of the central body in the widthwise direction to discharge the stored items loaded on the storage platform, and a second semi-portal reclaimer that travels in the longitudinal direction in a second area on the other side of the central body in the widthwise direction to discharge the stored items loaded on the storage platform, the first reclaimer including a first boom that drives a first scraper in a circulating manner to discharge the stored items. and a first portal supporting the first boom, the second reclaimer having a second boom that drives a second scraper in an orbit to dispense stored materials, and a second portal supporting the second boom, the central body having a beam portion extending over the entire traveling range of the first reclaimer and the second reclaimer and supporting the tip portion of the first portal and the tip portion of the second portal so that they can run, and a plurality of pillar portions extending vertically to support the beam portion and spaced apart from each other in the longitudinal direction, and an opening is formed between adjacent pillar portions.

In this way, the storage facility according to the embodiment has a central body with an opening formed therein, instead of a conventional retaining wall. Therefore, the storage facility according to the embodiment can reduce the weight of the structures in the storage area, thereby reducing civil engineering construction costs. Moreover, the storage facility according to the embodiment maintains the function of supporting the first and second portals that the retaining wall had.

The storage facility according to the embodiment also includes a control device that controls the first reclaimer and the second reclaimer, and the control device performs a contact avoidance process to avoid contact between the first boom and the second boom when the longitudinal distance between the first reclaimer and the second reclaimer is closer than a predetermined contactable distance.

Therefore, according to the storage facility of the embodiment, even if the first reclaimer and the second reclaimer approach each other, contact between the first boom and the second boom can be avoided.

In addition, in the storage facility according to the embodiment, the control device performs the contact avoidance process based on the boom distance, which is the distance between the first boom and the second boom when viewed in the longitudinal direction.

Therefore, with the storage facility according to the embodiment, contact between the first boom and the second boom can be reliably avoided.

The storage facility according to the embodiment is also equipped with a distance detector that is provided at the tip of one or both of the first boom and the second boom and is capable of detecting the boom-to-boom distance.

Therefore, the storage facility according to the embodiment can accurately detect the boom-to-boom distance.

In addition, in the storage facility according to the embodiment, the distance detector is a sensor that detects the boom-to-boom distance using ultrasonic waves or light, and has an emitter that emits ultrasonic waves or light, and the emitter is configured to rotate or swing around a rotation axis that extends in the longitudinal direction.

Therefore, with the storage facility according to the embodiment, the boom distance can be reliably detected even if the relative positions of the first boom and the second boom change when viewed in the longitudinal direction.

In addition, in the storage facility according to the modified example, the storage platform has a first bottom surface corresponding to the movable range of the first boom, a second bottom surface corresponding to the movable range of the second boom, and a boundary surface located between the first bottom surface and the second bottom surface, and the edge of the first bottom surface facing the boundary surface and the edge of the second bottom surface facing the boundary surface are at different heights, and the boundary surface is inclined at an angle greater than the angle of repose of the stored material.

In this way, in the storage facility according to the modified example, the boundary surface is located between the first bottom surface corresponding to the movable range of the first boom and the second bottom surface corresponding to the movable range of the second boom. Therefore, according to the storage facility according to the embodiment, the first boom and the second boom do not come into contact with each other. Moreover, since the boundary surface is inclined at an angle greater than the angle of repose of the stored material, the stored material does not remain at the boundary surface.

In addition, in the storage facility according to the embodiment, the first boom is configured to be able to drive the first scraper in a circular motion in both the forward and reverse directions, and the second boom is configured to be able to drive the second scraper in a circular motion in both the forward and reverse directions.

Therefore, with the storage facility according to the embodiment, the rotation direction of the first scraper and the second scraper can be set arbitrarily, improving the degree of freedom in removing stored items.

10 Storage platform 11 First area 12 Second area 13 First bottom surface 14 Second bottom surface 15 Boundary surface 20 Central body 21 Beam portion 22 Column portion 23 Opening 30 First reclaimer 31 First boom 32 First portal 35 First scraper 40 Second reclaimer 41 Second boom 42 Second portal 45 Second scraper 50 First discharge conveyor 60 Second discharge conveyor 70 Distance detector 71 Discharge portion 72 Rotating shaft 80 Control device 100 Storage equipment 101 Storage item

Claims (7)

1. A storage facility having a length direction and a width direction,
A storage platform on which stored items are loaded;
a central body provided at a center of the storage table in the width direction and extending in the longitudinal direction;
A semi-portal first reclaimer that travels in the longitudinal direction in a first area on one side of the central body in the width direction and dispenses the stored items loaded on the storage table;
a second reclaimer of a semi-portal type that travels in the longitudinal direction in a second area on the other side of the central body in the width direction and dispenses the stored items loaded on the storage table;
The first reclaimer has a first boom that drives a first scraper in a circulating manner to discharge stored materials, and a first portal that supports the first boom,
The second reclaimer has a second boom that drives a second scraper in a circulating manner to discharge the stored material, and a second portal that supports the second boom,
The central body has a beam portion extending over the entire length of the traveling range of the first reclaimer and the second reclaimer and supporting the tip portion of the first portal and the tip portion of the second portal so that they can travel, and a plurality of column portions extending vertically to support the beam portion and spaced apart from each other in the longitudinal direction, and an opening is formed between adjacent column portions. A control device for controlling the first reclaimer and the second reclaimer is provided,
The storage facility described in claim 1, wherein the control device performs contact avoidance processing to avoid contact between the first boom and the second boom when the longitudinal distance between the first reclaimer and the second reclaimer is closer than a predetermined contactable distance. The storage facility according to claim 2 , wherein the control device performs the contact avoidance processing based on a boom-to-boom distance, which is the distance between the first boom and the second boom when viewed from the longitudinal direction. The storage facility according to claim 3, further comprising a distance detector provided at the tip of one or both of the first boom and the second boom, capable of detecting the boom-to-boom distance. The distance detector is a sensor that detects a boom distance using ultrasonic waves or light, and has an emitter that emits ultrasonic waves or light,
The storage facility according to claim 4 , wherein the discharge portion is configured to rotate or swing about an axis of rotation extending in the longitudinal direction. The storage platform includes:
a first bottom surface corresponding to a movable range of the first boom;
a second bottom surface corresponding to a movable range of the second boom;
a boundary surface located between the first bottom surface and the second bottom surface;
an edge of the first bottom surface on the boundary surface side and an edge of the second bottom surface on the boundary surface side have different heights;
The storage facility of claim 1 , wherein the boundary surface is sloped . The first boom is configured to be able to drive the first scraper to rotate in both a forward rotation direction and a reverse rotation direction,
7. The storage facility according to claim 1, wherein the second boom is configured to be able to drive the second scraper to rotate in both a forward rotation direction and a reverse rotation direction.

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