JP7829906B2 - Granular material storage tank and method for assembling the granular material storage tank - Google Patents

Description

Applicable to Article 30, Paragraph 2 of the Patent Law: On December 10, 2020, Zennoh Pearl Rice Co., Ltd. publicly demonstrated a granular storage tank and a method for assembling a granular storage tank at its Fukuoka Plant, West Japan Business Headquarters.

This invention relates primarily to a granular storage tank for storing granular contents such as grains, and to a method for assembling such a granular storage tank.

Traditionally, granular material storage tanks have been used in factories that process grains (including rice, wheat, corn, and legumes) and various types of pellets and other granular materials. The tank bodies are generally shaped either circular (cylindrical tanks) or rectangular (square tanks). The width (diameter) and height (length) of the tank body are set to correspond to the volume of granular material to be stored and the available installation space.

A known type of cylindrical granular material storage tank is constructed by processing metal sheets into cylindrical shapes and connecting multiple of these cylindrical bodies vertically. Each cylindrical body has flanges at its upper and lower ends, and these flanges have numerous openings. When connecting the cylindrical bodies vertically, the openings in the flanges of the vertically positioned cylindrical bodies are joined together with bolts to form a tank body of the required length.

However, a tank body constructed by connecting multiple cylindrical bodies as described above presents the following challenges:

Since multiple cylindrical bodies are connected by flanges at their upper and lower ends, the cylindrical bodies themselves need to be rigid. Furthermore, forming large cylindrical bodies from metal sheets requires metal sheets of a thickness corresponding to their size. When forming cylindrical bodies from highly rigid metal sheets in this way, processing is not easy, and achieving a perfectly circular cross-sectional shape is difficult.
Because it is difficult to form the inner surface of the flanges provided at the upper and lower ends of the cylindrical body into a perfect circle, steps and gaps tend to occur at the connection points between the flanges. This can cause granular material, which is the stored material, to remain in these steps and gaps, and if the granular material is grain, there is a risk of pest infestation in the residue.
Generally, granular material storage tanks have large volumes, with a minimum of 1 cubic meter and it is not uncommon for them to be as large as 30 cubic meters. Consequently, the entire load from the cylindrical body itself and the contents is applied to the flanges and the cylindrical bodies supporting the flanges, and due to the distortion at the contact surface between the flanges, a large uneven load occurs. To withstand such a large uneven load, the steel material used for the cylindrical bodies needs to be sufficiently thick (at least 2 mm) even for small diameters for strength reasons, and it is not uncommon for larger diameters to have a thickness of 5 mm or more. Furthermore, in order to allow the contents of the tank body to descend without resistance, it is desirable that the inner surface of the tank body be free of any snagging steps. To achieve this, it is necessary to change the diameters of the upper and lower ends of each cylindrical body so that the diameter of the upper end of the lower cylindrical body is slightly larger than the diameter of the lower end of the upper cylindrical body, so that there is no snagging step at the joint between the upper and lower cylindrical bodies, and this is not an easy process to manufacture.
As the thickness of the steel material used for the cylindrical body increases, the weight of the cylindrical body also increases. Furthermore, when transporting it from the processing plant to the installation site, it is necessary to transport either the large cylindrical body or the assembled tank body, which inevitably results in an extremely inefficient method of transportation, much like transporting air. Therefore, it lacks convenience when transporting from the processing plant to the installation site.

In configurations where metal cylindrical bodies are joined vertically using flanges, the above-mentioned challenges exist. Therefore, modular tanks, where the tank body is constructed by connecting subdivided panels, have also been proposed. For example, a rectangular modular storage tank formed from unit panels and reinforcing frames has been proposed.

However, the rectangular, prefabricated storage tanks, formed from unit panels and reinforcing frames, have the following challenges:

In rectangular, prefabricated storage tanks, the pressure from the contents is distributed across the large surface area of each unit panel, which can lead to the panel bulging.
To prevent the bulging of the unit panels, measures such as increasing the thickness of the steel plates that make up the unit panels, adding reinforcement to the unit panels, or providing flanges with connecting holes on all four sides of the unit panels for connection are necessary to increase the rigidity of the tank housing itself in accordance with the volume and weight of the contents being stored.
As a result, the weight of the unit panels increases, leading to higher material and processing costs, and ultimately reducing the productivity of the unit panels.

On the other hand, while not a storage tank for granular materials, a cylindrical, prefabricated storage tank has been proposed for liquids (see, for example, Patent Document 1).

The cylindrical storage tank disclosed in Patent Document 1 consists of arc-shaped metal outer wall elements that form a cylindrical body, and the tank body is constructed by combining multiple metal outer wall elements.

Japanese Patent Publication No. 2009-12849

However, while the diameter and length of the tank body of a granular material storage tank need to be set to correspond to the volume of granular material to be stored and the installation space, Patent Document 1 does not disclose any modifications to the diameter or length of the tank body.

In particular, since the metal outer wall elements are formed by plastic deformation into an arc shape, changing the diameter of the tank body requires changing the radius of curvature of the metal outer wall elements, making it difficult to change the diameter of the tank body.

Furthermore, arc-shaped metal exterior wall elements must be manufactured by processing metal sheets into an arc shape. Therefore, it is assumed that arc-shaped metal exterior wall elements have a thickness that allows for this processing.

Increasing the thickness of the steel material used for the arc-shaped metal exterior wall elements increases their weight, leading to higher material and processing costs. Furthermore, it becomes less convenient when transporting multiple metal exterior wall elements from the processing plant to the installation site.

This invention has been made in view of the above problems, and aims to provide a granular material storage tank and a method for assembling a granular material storage tank that allows the diameter and length of the tank body to easily accommodate the volume of granular material to be stored and the installation space, while also significantly reducing material and processing costs, and furthermore, providing high convenience for transportation from the processing plant to the installation site and facilitating assembly at the installation site.

The granular material storage tank of the present invention is
A granular material storage tank having a cylindrical tank body,
The tank body is
It consists of one or more cylindrical bodies arranged in the vertical direction,
The aforementioned cylindrical body is
The exterior wall members are connected at their ends in the circumferential direction and are composed of one or more exterior wall members that are curved in an arbitrary arc shape in the circumferential direction by elastic deformation.

The present invention relates to a method for assembling a granular storage tank, which comprises a cylindrical tank body.
The tank body is composed of one or more cylindrical bodies,
The one or more outer wall members constituting the cylindrical body are connectable at their ends in the circumferential direction of the tank body, and are capable of bending into any arbitrary arc shape in the circumferential direction by elastic deformation.
A cylindrical assembly step in which one or more of the outer wall members are elastically deformed in the circumferential direction, the ends of the outer wall members are connected to form a cylindrical body, and the tank body is formed by one or more of the cylindrical bodies,
A lower connection step involves connecting an inverted cone-shaped hopper, or a lower member with a circular top surface, to the lower part of the tank body by insertion,
Includes.

According to the present invention, the granular material storage tank and the method for assembling the granular material storage tank allow the diameter and length of the tank body to be easily adapted to the volume of granular material to be stored and the installation space, while significantly reducing material and processing costs. Furthermore, the lightweight, flat outer wall members can be stacked for convenient transportation from the processing plant to the installation site, resulting in extremely low transportation costs. Additionally, welding and other processing costs at the installation site are unnecessary, and assembly and disassembly are easily performed.

Figure 1 is a perspective view of a granular material storage tank according to Embodiment 1 of the present invention. Figure 2 is a front view of the exterior wall member. Figure 3 is a cross-sectional view taken along the line A-A in Figure 2. Figure 4 is a flowchart showing the assembly process of a granular material storage tank according to Embodiment 1 of the present invention. Figure 5 is a perspective view showing the state in which the outer wall members are connected to assemble the first cylindrical body. Figure 6 is a plan cross-sectional view of the connecting portion where the exterior wall members are connected. Figure 7 is a perspective view showing the first cylinder and the second cylinder connected together. Figure 8 is an enlarged cross-sectional view showing the state in which the end of the lower opening of the first cylinder in Figure 7 is inserted into the inside of the upper opening of the second cylinder. Figure 9 is an enlarged cross-sectional view showing the state in which the lower end of the side connecting portion of the upper cylindrical body and the upper end of the side connecting portion of the lower cylindrical body are connected by a fixing member. Figure 10 is an enlarged front view, taken from direction B in Figure 9, showing the portion where the lower end of the side connecting portion of the upper cylindrical body and the upper end of the side connecting portion of the lower cylindrical body are connected by a fixing member. Figure 11 is a perspective view showing the tank body with the upper lid and lower hopper attached. Figure 12 is a front view of the outer wall member constituting a granular material storage tank according to Embodiment 2 of the present invention. Figure 13 is a perspective view showing the state in which the upper lid is attached to the tank body of the granular material storage tank according to Embodiment 3. Figure 14 is a cross-sectional view showing the inclination angle of the inclined surface of the upper lid and the angle of repose of the granular material stored in the granular material storage tank. Figure 15 is a cross-sectional view showing the movement of the surface of granular material when granular material stored in a granular material storage tank is discharged.

A granular material storage tank according to one embodiment of the present invention is a granular material storage tank having a cylindrical tank body,
The tank body is
It consists of one or more cylindrical bodies arranged in the vertical direction,
The aforementioned cylindrical body is
The structure consists of one or more outer wall members, each having its ends connected in the circumferential direction and curved in an arc shape in the circumferential direction by elastic deformation (first configuration).

According to the above configuration, the tank body is composed of one or more cylindrical bodies, and the cylindrical bodies are made up of one or more outer wall members, the ends of which are connected in the circumferential direction and which are curved in an arbitrary arc shape in the circumferential direction by elastic deformation.
Therefore, the diameter and length of the tank body can be easily changed by changing the number of cylindrical bodies arranged vertically and the number of outer wall members that make up the cylindrical bodies.
Furthermore, since the exterior wall components are made of thin, elastically deformable plates that can be curved in an arc, material and processing costs can be reduced, and they are highly convenient because they can be stacked and transported and stored from the processing plant to the installation site.
Furthermore, because the exterior wall components are thin and lightweight, they are easy to move and can be easily assembled at the installation site.

In the first configuration described above,
The tank body is equipped with a lower member connected to the lower part,
The lower member is formed as an inverted cone-shaped hopper or as a member with a circular top surface, and is connected to the lower part of the tank body.
The lower end of the tank body and the upper end of the lower member may be connected by being inserted into each other (second configuration).

According to the above configuration, the tank body is composed of one or more cylindrical bodies, and each cylindrical body is composed of one or more elastically deformable outer wall members. In addition, a lower member with a circular top surface is connected to the lower part of the tank body.
As a result, even if the tank body is composed of multiple cylindrical sections at the top and bottom, the tank body will elastically deform due to the internal pressure caused by the granular material filling inside, so that its cross-sectional shape naturally becomes a perfect circle.
In this way, the cross-sectional shape of the tank body is formed into a circular shape by elastically deforming the outer wall members, thus eliminating the need for the precise machining required to create a circular cross-section, which is the most difficult aspect of forming a cylindrical tank body.

In the first or second configuration described above,
The aforementioned cylindrical body is
It has an upper opening and a lower opening,
When the tank body is composed of a plurality of cylindrical bodies arranged vertically,
In a pair of vertically adjacent cylindrical bodies, the upper opening of the lower cylindrical body and the end of the lower opening of the upper cylindrical body may be connected in an inserted state (third configuration).

According to the above configuration, when the tank body is composed of multiple cylindrical bodies vertically, the ends of a pair of adjacent cylindrical bodies in the vertical direction are connected by insertion.
Therefore, the length of the tank body can be easily changed by changing the number of cylindrical bodies connected in the vertical direction.
Furthermore, because the thickness of the exterior wall members is thin, when the upper and lower cylindrical bodies are inserted and connected, steps or gaps are less likely to occur at the connection point. As a result, granular material is less likely to remain, and the occurrence of pests in the remaining material can be suppressed.
Furthermore, flange processing is not required to connect adjacent cylindrical bodies in the vertical direction, which can reduce processing costs.

In the third configuration described above,
In a pair of cylindrical bodies connected vertically, the length of the inner circumference of the upper opening of the lower cylindrical body may be made longer than the length of the outer circumference of the lower opening of the upper cylindrical body, or the length of the outer circumference of the upper opening of the lower cylindrical body may be made shorter than the length of the inner circumference of the lower opening of the upper cylindrical body (fourth configuration).

According to the above configuration, by setting the length of the outer circumference of the lower opening of the upper cylinder and the length of the inner circumference of the upper opening of the lower cylinder, or the length of the inner circumference of the lower opening of the upper cylinder and the length of the outer circumference of the upper opening of the lower cylinder, in a predetermined relationship, when the tank body is composed of multiple cylinders, the lower opening of the upper cylinder and the upper opening of the lower cylinder of a pair of vertically adjacent cylinders can be connected by insertion.

In the above configurations 1 to 4,
The aforementioned exterior wall member is
The outer wall body is formed of a thin plate that is elastically deformable so as to bend in any arc shape in the circumferential direction of the cylindrical body,
The cylindrical body has side connecting portions arranged at both ends of the outer wall body in the circumferential direction, which connect the ends of the outer wall members together.
It may have (fifth configuration).

According to the above configuration, the exterior wall member is made of a thin plate that can be elastically deformed to curve in any arc shape, and side connecting parts are provided at both ends of the exterior wall body to connect the ends of the exterior wall members.
By forming the main body of the exterior wall from a thin, elastically deformable sheet metal, it can be bent into any desired arc shape with minimal force by hand, without the need for molding equipment or tools, and at the same time, material and processing costs can be reduced.
Furthermore, in the state before the exterior wall members are elastically deformed and curved, the exterior wall members themselves are flat, plate-like bodies. This allows for a thinner exterior wall member thickness, and they can be efficiently transported and stored by stacking them flat from the processing plant to the installation site, making them highly convenient.

In the fifth configuration described above,
The configuration may further include a fixing member for fixing the side connecting portion provided on the outer wall member constituting one of the vertically adjacent cylindrical bodies to the side connecting portion provided on the outer wall member constituting the other cylindrical body (sixth configuration).

According to the above configuration, a pair of cylindrical bodies adjacent to each other in the vertical direction are fixed by a fixing member.
Therefore, the strength of the granular material storage tank can be improved with a simple configuration.
Furthermore, the reason why the tank's outer wall members can be made of materials significantly thinner than conventional materials without structural problems is that when the tank is filled with the contents that bear the greatest load, a load is applied from the inside in the direction of expanding the diameter of the cylinder. However, because it is a cylindrical body to begin with, its shape does not change beyond that point, and even if a strong tensile load is applied to the outer wall members, the tensile strength of the thin metal outer wall members is extremely high, so they can withstand it sufficiently. In addition, even with regard to vertical loads on the outer wall members, the thin metal outer wall members exhibit extremely high strength because they are cylindrical bodies, so they can withstand that as well.

A method for assembling a granular storage tank according to one embodiment of the present invention is a method for assembling a granular storage tank having a cylindrical tank body,
The tank body is composed of one or more cylindrical bodies,
The one or more outer wall members constituting the cylindrical body are connectable at their ends in the circumferential direction of the tank body, and are capable of bending in an arc shape in the circumferential direction by elastic deformation.
A cylindrical assembly step in which one or more of the outer wall members are elastically deformed in the circumferential direction, the ends of the outer wall members are connected to form a cylindrical body, and the tank body is formed by one or more of the cylindrical bodies,
A lower connection step involves connecting an inverted cone-shaped hopper, or a lower member with a circular top surface, to the lower part of the tank body by insertion,
This includes (the seventh component).

According to the above configuration, the outer wall members constituting the cylindrical body are formed from thin, plate-like bodies that can be elastically deformed to curve in any desired arc shape, thus facilitating the transportation and deformation of the outer wall members at the installation site. Furthermore, since the tank body is composed of one or more cylindrical bodies, the granular material storage tank can be easily assembled at the installation site.
Furthermore, by connecting either an inverted cone-shaped hopper or a lower member with a circular top surface to the bottom of the tank body, a tank body with a circular cross-section can be easily assembled.

[Embodiment 1]
The granular storage tank 100 according to Embodiment 1 of the present invention will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and their descriptions will not be repeated. In order to make the explanation easier to understand, the drawings referred to below show the configuration in a simplified or schematic manner, and some components are omitted. Also, the dimensional ratios between components shown in each figure do not necessarily represent the actual dimensional ratios.

In the following diagram, arrow U indicates the upward direction of the granular material storage tank 100, and arrow D indicates the downward direction. Arrow I indicates the inner surface of the granular material storage tank 100, and arrow O indicates the outer surface. Arrow C indicates the circumferential direction of the granular material storage tank 100.

[Overall structure]
First, the overall configuration of the granular storage tank 100 and an outline of each component will be described. Figure 1 is a perspective view of the granular storage tank 100 according to Embodiment 1 of the present invention. The granular storage tank 100 according to this embodiment is used as a tank for storing grain (for example, rice) in a factory that processes grain. The granular storage tank 100 comprises a tank body 10, an upper lid 12, and a lower hopper 14.

The tank body 10 is a cylindrical body with a circular cross-section, and a storage space for storing granular material is formed inside. In this embodiment, the tank body 10 is constructed by connecting two cylindrical bodies 30 (a first cylindrical body 31 and a second cylindrical body 32) in the vertical direction.

The upper lid 12 is the part that closes the top of the tank body 10. The upper lid 12 has a circular planar shape. A granular material inlet 13 is provided in the upper lid 12. The granular material inlet 13 communicates with the storage space inside the tank body 10. For example, a chute pipe (not shown) from a lifting machine for transporting grain is connected to the granular material inlet 13. The grain supplied from the chute pipe is fed into the tank body 10 through the granular material inlet 13.

The lower hopper 14 is a conical hopper and is the part that closes the lower part of the tank body 10. The lower hopper 14 is an example of the lower component of the present invention. The upper surface of the lower hopper 14 is formed in a circular shape. A granular material discharge port 15 is formed in the center of the lower surface of the lower hopper 14. The granular material discharge port 15 communicates with the storage space inside the tank body 10. The granular material stored in the granular material storage tank 100 is discharged to the outside of the tank body 10 through the granular material discharge port 15 and transported, for example, to a grain processing device (not shown).

The granular material discharge port 15 is openable and closable by a shutter plate 16 mounted on its lower surface. The shutter plate 16 is configured to switch between an open state and a closed state of the granular material discharge port 15 by an actuator 17. The actuator 17 is, for example, an air cylinder operated by pneumatic pressure, and the actuator 17 is driven and controlled by a drive control unit (not shown).

In addition to a conical hopper, a lower base plate can be used as the lower component of this invention. The lower base plate is a flat plate-shaped component with a circular planar shape. The lower base plate is configured to allow for the mechanical removal of granular material by providing hatches on its bottom or side surface (not shown).

Here, as shown in Figures 1 and 5, each cylindrical body 30 (first cylindrical body 31, second cylindrical body 32) constituting the tank body 10 is composed of multiple outer wall members 50 that are easily elastically deformed and curved in an arc shape in the circumferential direction of the tank body 10. Furthermore, the multiple outer wall members 50 are connected to each other by side connecting portions 54 located at their ends in the circumferential direction. In this embodiment, each cylindrical body 30 is constructed by connecting multiple outer wall members 50.

As shown in Figures 3 and 5, the outer wall member 50 is made of a thin steel plate that, when flat, will curve and sag in the middle under its own weight if both ends are held. Therefore, as shown in Figure 5, the assembly worker can connect multiple outer wall members 50 in the circumferential direction of the tank body 10 by elastically deforming the flat outer wall member 50 by hand. Note that the outer wall members constituting the cylindrical body do not necessarily have to be multiple. A single outer wall member may be curved into an arc shape and its ends connected to form the cylindrical body.

As shown in Figure 7, the first cylindrical body 31 and the second cylindrical body 32, which are constructed by connecting multiple outer wall members 50, are connected by inserting the lower end of the first cylindrical body 31 into the upper end of the second cylindrical body 32. Specifically, they are connected by inserting the lower end of the first cylindrical body 31 (the end on the lower opening 312 side) into the upper opening 321 of the second cylindrical body 32. Therefore, the dimensions of the openings of the first cylindrical body 31 and the second cylindrical body 32 are set to allow for insertion and connection.

In this embodiment, the lower end of the first cylindrical body 31 (the end on the lower opening 312 side) is inserted into the upper opening 321 of the second cylindrical body 32, which is positioned lower. However, the invention is not limited to this configuration. While inserting the bodies in this configuration creates a downward-facing step inside the tank body, making it less likely for contents to remain, the steel plates used for the outer wall are extremely thin. Therefore, the lower end of the first cylindrical body 31 (the end on the lower opening 312 side) may be inserted (externally fitted) into the outside of the upper opening 321 of the second cylindrical body 32. In this invention, "cylinders are inserted and connected" includes both the state in which the end of the upper cylindrical body is inserted into the inside of the opening of the lower cylindrical body, and the state in which the end of the upper cylindrical body is externally fitted to the outside of the opening of the lower cylindrical body.

As shown in Figure 11, the upper lid 12 and lower hopper 14, positioned at the top and bottom of the tank body 10, are attached after the tank body 10 is constructed by connecting the first cylindrical body 31 and the second cylindrical body 32. Specifically, the upper lid 12 is attached to cover the upper opening of the tank body 10 (the upper opening 311 of the first cylindrical body 31), and the lower hopper 14 is connected to the lower opening of the tank body 10 (the lower opening 322 of the second cylindrical body 32) by being inserted into it.

In this way, by elastically deforming the outer wall member 50 that constitutes the tank body 10, the cross-sectional shape of the tank body 10 is formed to be circular. Therefore, the most difficult part of forming a cylindrical tank body 10—precise machining to create a circular cross-section—is completely unnecessary.

As shown in Figure 1, in this embodiment, the tank body 10 is composed of two cylindrical bodies 30, a first cylindrical body 31 and a second cylindrical body 32. However, the number of cylindrical bodies constituting the tank body is not limited. The tank body may be composed of one cylindrical body or three or more cylindrical bodies. By changing the number of cylindrical bodies, the length of the tank body can be easily changed. The number of connected cylindrical bodies can be set according to conditions such as the type of granular material to be stored inside, the storage amount, and the installation space.

Furthermore, in this embodiment, each cylindrical body is constructed by connecting four outer wall members 50, but the number of outer wall members constituting the cylindrical body is not limited. By changing the number of outer wall members, the diameter of the tank body can be easily changed. The number of outer wall members constituting the cylindrical body can be set according to conditions such as the type of granular material stored inside, the storage amount, and the installation space.

The following sections will provide a detailed explanation of each component that makes up the tank body 10 of the granular material storage tank 100, as well as a detailed explanation of the assembly process of the granular material storage tank 100.

[Exterior wall components]
First, let's describe the exterior wall member 50. Figure 2 is a front view of the exterior wall member 50. Figure 3 is a cross-sectional view taken along line A-A in Figure 2. The exterior wall member 50 is a component that makes up each cylindrical body 30. As shown in Figure 2, the exterior wall member 50 has an exterior wall body 52, a side connecting portion 54, and a reinforcing member 56.

The outer wall body 52 and the side connecting portion 54 are integrally formed, and the outer wall body 52 is formed from a plate-like material that can be elastically deformed to curve in an arc shape in the circumferential direction of the cylindrical body 30. The material constituting the outer wall body 52 and the side connecting portion 54 can be made from a general metal material used in granular storage tanks (for example, stainless steel plate), but the thickness of the steel plate is extremely thin compared to the steel material used in conventional granular storage tanks. The thickness is preferably such that an assembly worker can elastically deform the flat outer wall body 52 by hand. For example, the thickness of the steel plate is preferably about 0.3 mm to 1.0 mm, and more preferably about 0.5 mm to 0.8 mm.

In this embodiment, rectangular members can be used as the steel plates constituting the outer wall body 52 and the side connecting portion 54. These are stainless steel plates of standardized length with a standard width (length C in the circumferential direction), cut to predetermined lengths. By cutting standardized stainless steel plates to predetermined lengths and bending both sides to form the outer wall body 52 and the side connecting portion 54, material and processing costs can be significantly reduced. The dimensions of the outer wall body 52 can be determined considering factors such as the diameter and length of the tank body 10, as well as the availability of stainless steel plates and the convenience of transporting and storing the outer wall members 50.

The side connecting portion 54 is a flange-shaped member positioned at both ends of the outer wall body 52 in the circumferential direction. The side connecting portion 54 is formed integrally with the outer wall body 52 by bending a steel plate. The side connecting portion 54 is provided to connect the ends of the outer wall members 50. A reinforcing member 56 is attached to the side connecting portion 54. The reinforcing member 56 is attached to the outer wall body 52, for example, by spot welding. As the reinforcing member 56, for example, a steel material with an L-shaped cross-section can be used (see Figure 3).

The reinforcing member 56 may be attached to the outer wall body 52 and the side connecting portion 54 by welding or other means, or it may be a separate component from the outer wall body 52 and the side connecting portion 54, and when the outer wall members 50 are connected to form a cylindrical body, it may be brought into contact with the outer wall body 52 and the side connecting portion 54 and fastened together with bolts and nuts. Note that the reinforcing member 56 is not limited to an angle (L-shaped steel material); for example, a thick metal plate may be used.

According to this embodiment, by forming an L-shaped end on the outer wall member 50 to create a side connecting portion 54, reinforcing it with a reinforcing material 56, and connecting these ends to form a cylindrical body 30, the following effects are obtained.

Although the outer wall member 50 is made of a thin plate-like body, the load applied to the outer wall member 50 when the contents are filled is a tensile load. Since the outer wall member 50 has extremely high tensile strength, even a thin member possesses sufficient strength. On the other hand, bending stress is applied to the joints between the ends of the outer wall member 50. Therefore, by attaching and fixing reinforcing members 56 to these areas, the strength of the tank body 10 can be increased.

In this embodiment, the spacing between the side connecting portions 54, which are positioned at both ends of the outer wall body 52, is set to be L1 at both the upper and lower ends. In other words, the side connecting portions 54 are arranged parallel to each other.

The side connecting portion 54 is positioned such that its upper end coincides with the upper end of the outer wall body 52, and its lower end is positioned a distance H1 above the lower end of the outer wall body 52. The lower end of the side connecting portion 54 is positioned above the lower end of the outer wall body 52 to prevent interference between the side connecting portion 54 and other cylindrical bodies 30 when connecting multiple cylindrical bodies 30 (first cylindrical body 31, second cylindrical body 32) by insertion, as shown in Figures 7 and 8.

The outer wall body 52 has multiple upper connecting holes 57 and lower connecting holes 58. The positions of the upper and lower connecting holes 58 are set so that when connecting multiple cylindrical bodies 30 (first cylindrical body 31, second cylindrical body 32) by insertion, the lower connecting hole 58 of the upper cylindrical body 30 (first cylindrical body 31) and the upper connecting hole 57 of the lower cylindrical body 30 (second cylindrical body 32) are aligned, allowing them to be fixed with fastening means such as bolts and nuts.

As shown in Figure 3, the side connecting portions 54 located at both ends of the outer wall body 52 each have multiple side connecting holes 59 arranged vertically. The reinforcing member 56 also has openings 561 at positions corresponding to the side connecting holes 59. The positions of the side connecting holes 59 are set so that when connecting the ends of the outer wall members 50, the side connecting holes 59 of one side connecting portion 54 are aligned with those of the other side connecting portion 54, allowing them to be fixed using fastening means such as bolts and nuts.

[Assembly Process]
Next, the process of assembling the granular material storage tank 100 using the outer wall member 50 described above will be explained. Figure 4 is a flowchart showing the assembly process of the granular material storage tank 100 according to Embodiment 1 of the present invention.

As shown in Figure 4, the assembly process of the granular material storage tank 100 according to this embodiment includes a cylindrical assembly process, an upper connection process, and a lower connection process.

In the cylindrical body assembly process, multiple outer wall members 50 are elastically deformed in the circumferential direction, and the ends of the outer wall members 50 are connected to form the cylindrical body 30 (first cylindrical body 31, second cylindrical body 32). The first cylindrical body 31 and the second cylindrical body 32 are then connected to form the tank body 10 (see Figures 5 to 7).

In the lower connection process, the lower hopper 14, which has a circular top surface, is connected to the lower part of the tank body 10 by insertion (see Figure 11).

Furthermore, the construction can also include an upper connection process. For example, it may simply involve passing metal beams in a cross shape, or laying a flat plate on top of the beams. Alternatively, the upper lid 12, which has a circular planar shape, can be connected to the upper part of the tank body 10 by insertion (see Figure 11). The following description will use an example where the upper lid 12 and the upper part of the tank body 10 are connected by insertion.

Note that the cylindrical assembly process, the upper connection process, and the lower connection process do not necessarily have to be performed in this order. For example, the order of the upper connection process and the lower connection process may be reversed.

Furthermore, it is not necessary to perform the upper and lower connection processes after completing the tank body 10. For example, after assembling the uppermost cylindrical body 30 (first cylindrical body 31), the upper connection process of connecting the upper lid portion 12 to the uppermost cylindrical body 30 (first cylindrical body 31) may be performed before connecting the next cylindrical body 30 (second cylindrical body 32).

Similarly, after assembling the lowest cylindrical body 30 (second cylindrical body 32), a lower connection step may be performed to connect the lower hopper 14 to the lower part of the lowest cylindrical body 30 (second cylindrical body 32) before connecting the already assembled cylindrical body 30 (first cylindrical body 31).

The following sections will describe in detail the assembly process of the granular material storage tank 100 and the configuration of each part of the granular material storage tank 100.

[Cylinder assembly process]
Figure 5 is a perspective view showing the assembly of the first cylindrical body 31 by connecting the outer wall members 50. Figure 6 is a plan cross-sectional view of the connecting portion where the outer wall members 50 are connected.

As shown in Figure 5, the first cylindrical body 31 is assembled by connecting four outer wall members 50 in the circumferential direction. Since the outer wall members 50 are made of thin steel plates, the assembler can connect multiple outer wall members 50 in the circumferential direction by elastically deforming the flat outer wall body 52 by hand. The four outer wall members 50 are connected by their side connecting portions 54 (and reinforcing members 56) located at their respective circumferential ends.

As shown in Figure 6, the side connecting portions 54 and reinforcing members 56 of the outer wall members 50, which are arranged adjacent to each other in the circumferential direction of the first cylindrical body 31, are fastened together with bolts 61 and nuts 62. At this time, a spacer 64 is interposed between the pair of side connecting portions 54 to be fastened. The spacer 64 has a length extending from the top to the bottom of the side connecting portion 54. By changing the thickness of the spacer 64, the lengths of the inner and outer circumferential surfaces of the upper opening 311 and lower opening 312 of the first cylindrical body 31 can be adjusted.

In this embodiment, the thickness of the spacer 64 is constant at both the upper and lower ends. Therefore, the length of the inner circumferential surface at the upper opening 311 and the lower opening 312 of the first cylindrical body 31 is the same, and the length of the outer circumferential surface at the upper opening 311 and the lower opening 312 of the first cylindrical body 31 is also the same.

In this later step, when connecting the first cylindrical body 31 and the second cylindrical body 32 to form the tank body 10, the lower end of the first cylindrical body 31 (the end on the lower opening 312 side) is inserted into the upper opening 321 of the second cylindrical body 32 (see Figures 7 and 8). Therefore, the length of the outer circumferential surface of the lower opening 312 of the first cylindrical body 31 must be set to be less than or equal to the length of the inner circumferential surface of the upper opening 321 of the second cylindrical body 32.

In this embodiment, the thickness of the spacer 64 used when assembling the first cylindrical body 31 is changed, and the thickness of the spacer 64 used when assembling the second cylindrical body 32 is changed, so that the length of the outer circumferential surface of the lower opening 312 of the first cylindrical body 31 is less than or equal to the length of the inner circumferential surface of the upper opening 321 of the second cylindrical body 32.

Furthermore, the outer wall member 50 in this embodiment is made of thin steel plate. Therefore, the length that needs to be adjusted with the spacer 64 to allow the lower end of the first cylindrical body 31 (the end on the lower opening 312 side) to be inserted into the upper opening 321 of the second cylindrical body 32 is very small. For this reason, the thickness of the spacer 64 used when assembling the first cylindrical body 31 and the thickness of the spacer 64 used when assembling the second cylindrical body 32 may all be different. However, for example, spacer 64 of the same thickness may be prepared, and the length of the inner circumferential surface may be adjusted by changing the number of interposed spacer 64 to change their thickness.

Furthermore, when connecting the first cylindrical body 31 and the second cylindrical body 32 to form the tank body 10, it is also possible to connect them by inserting the upper end of the second cylindrical body 32 (the end on the upper opening 321 side) into the lower opening 312 of the first cylindrical body 31. In this case, the outer wall member 50 should be used upside down so that the side connecting portion 54 of the lower second cylindrical body 32 does not interfere with the side connecting portion 54 of the upper first cylindrical body 31.

Figure 7 is a perspective view showing the first cylindrical body 31 and the second cylindrical body 32 connected. As shown in Figure 7, the first cylindrical body 31 is assembled by connecting the side connecting portions 54 provided on each of the four outer wall members 50, thereby connecting the four outer wall members 50 in the circumferential direction.

In other words, the lower end of the first cylindrical body 31 (the end on the lower opening 312 side) is inserted into the upper opening 321 of the second cylindrical body 32 to assemble it.

Here, when assembling the second cylinder 32, the first cylinder 31, which was assembled earlier, may be lifted upwards, and the second cylinder 32 may be assembled below the first cylinder 31. In this case, by lowering the first cylinder 31 onto the assembled second cylinder 32, the first cylinder 31 and the second cylinder 32 can be connected, and the granular storage tank 100 can be assembled even without a large workspace.

Furthermore, as described above, when connecting the first cylindrical body 31 and the second cylindrical body 32 to form the tank body 10, the lower end of the first cylindrical body 31 (the end on the lower opening 312 side) is inserted into the upper opening 321 of the second cylindrical body 32 to connect them (see Figures 7 and 8). Therefore, the thickness of the spacer 64 used when assembling the second cylindrical body 32 is set such that the length of the outer circumferential surface of the lower opening 312 of the first cylindrical body 31 is less than or equal to the length of the inner circumferential surface of the upper opening 321 of the second cylindrical body 32.

As shown in Figure 7, the first cylindrical body 31 and the second cylindrical body 32 are connected by inserting the lower end of the first cylindrical body 31 (the end on the lower opening 312 side) into the upper opening 321 of the second cylindrical body 32, thereby forming the tank body 10.

Here, the connection between the first cylindrical body 31 and the second cylindrical body 32 will be explained in more detail. Figure 8 is an enlarged cross-sectional view showing the end of the lower opening 312 of the first cylindrical body 31 inserted into the upper opening 321 of the second cylindrical body 32 in Figure 7. Figure 9 is an enlarged cross-sectional view showing the lower end of the side connecting portion 54 of the first cylindrical body 31 and the upper end of the side connecting portion 54 of the second cylindrical body 32 connected by a fixing member 70. Figure 10 is an enlarged front view showing the portion where the lower end of the side connecting portion 54 of the first cylindrical body 31 and the upper end of the side connecting portion 54 of the second cylindrical body 32 are connected by the fixing member 70, viewed from direction B in Figure 9.

As shown in Figure 8, when connecting the first cylindrical body 31 and the second cylindrical body 32, the lower end of the first cylindrical body 31 (the end on the lower opening 312 side) is inserted into the upper opening 321 of the second cylindrical body 32.

After the lower end of the first cylindrical body 31 (the end on the lower opening 312 side) is inserted into the upper opening 321 of the second cylindrical body 32, the upper connecting hole 57 provided in the outer wall member 50 constituting the second cylindrical body 32 and the lower connecting hole 58 provided in the outer wall member 50 constituting the first cylindrical body 31 are fastened together with bolts 65 and nuts 66.

Then, as shown in Figures 9 and 10, the side connecting portion 54 (and reinforcing member 56) provided on the outer wall member 50 constituting the second cylindrical body 32 and the side connecting portion 54 (and reinforcing member 56) provided on the outer wall member 50 constituting the first cylindrical body 31 are fixed together with fixing members 70. Specifically, the side connecting portion 54 (and reinforcing member 56) on the second cylindrical body 32 side and the side connecting portion 54 (and reinforcing member 56) on the first cylindrical body 31 side are sandwiched between two fixing members 70. Then, the side connecting hole 59 provided in the side connecting portion 54 on the second cylindrical body 32 side and the through hole 71 of the fixing member 70 are fastened together with bolts 73 and nuts 74, and the side connecting hole 59 provided in the side connecting portion 54 on the first cylindrical body 31 side and the through hole 71 of the fixing member 70 are fastened together with bolts 73 and nuts 74.

The portion where the lower end of the first cylindrical body 31 (the end on the lower opening 312 side) is inserted into the upper opening 321 of the second cylindrical body 32 is fastened with bolts 65 and nuts 66 to the upper connecting hole 57 provided in the outer wall member 50 constituting the second cylindrical body 32 and the lower connecting hole 58 provided in the outer wall member 50 constituting the first cylindrical body 31. Furthermore, the side connecting portion 54 (and reinforcing member 56) provided in the outer wall member 50 constituting the second cylindrical body 32 and the side connecting portion 54 (and reinforcing member 56) provided in the outer wall member 50 constituting the first cylindrical body 31 are clamped together by a fixing member 70, and fastened with bolts 73 and nuts 74.

Regarding the insertion of the cylindrical bodies 30, the bolts 61 and nuts 62 used to connect the exterior wall members 50 may be loosely tightened, and after inserting the cylindrical bodies 30, the bolts 65 and nuts 66 at the connection point between the cylindrical bodies 30 and the bolts 61 and nuts 6 at the connection point between the exterior wall members 50 may be fully tightened.

[Top connection process]
Figure 11 is a perspective view showing the state in which the upper lid portion 12 and the lower hopper 14 are attached to the tank body 10. As shown in Figure 11, the upper lid portion 12 has an upper lid main body 121 and an upper connecting portion 123. The upper lid main body 121 has a circular planar shape. The upper connecting portion 123 is the part that connects to the upper part of the tank body 10. The upper connecting portion 123 is formed facing downward with respect to the peripheral edge of the upper lid main body 121. The shape of the upper connecting portion 123 is circular in plan view. An upper lid connecting hole 125 is formed in the upper connecting portion 123 at a position corresponding to the upper connecting hole 57 provided in the outer wall member 50 that constitutes the tank body 10.

The upper lid portion 12 is connected by inserting the upper connecting portion 123 into the upper opening of the tank body 10 (the upper opening 311 of the first cylindrical body 31). The length of the outer surface of the upper connecting portion 123 is set to a length that allows it to be inserted into the upper opening 311 of the first cylindrical body 31. After the upper connecting portion 123 is inserted, the upper lid portion 12 is attached to the tank body 10 using bolts and nuts.

[Lower connection process]
As shown in Figure 11, the lower hopper 14 has a lower hopper body 141 and a lower connecting portion 143. The lower hopper body 141 has a circular planar shape. The lower connecting portion 143 is the part that connects to the lower part of the tank body 10. The lower connecting portion 143 is formed upward on the periphery of the lower hopper body 141. The lower connecting portion 143 has a lower hopper connecting hole 145 formed at a position corresponding to the lower connecting hole 58 provided in the outer wall member 50 that constitutes the tank body 10.

The lower hopper 14 is connected by inserting the end of the lower hopper 14, which faces the lower opening (lower opening 322 of the second cylindrical body 32), into the inner side of the lower connecting portion 143. The length of the inner circumference of the lower connecting portion 143 is set to allow insertion of the end of the second cylindrical body 32 facing the lower opening 322. After being inserted into the lower connecting portion 143, the lower hopper 14 is attached to the tank body 10 using bolts and nuts.

Furthermore, sealing may be performed as the final step of assembly. The assembly of the cylindrical granular material storage tank 100 is completed by sealing the connecting parts of the cylindrical body 30 and the connecting parts of the lower hopper 14 with a sealing agent to prevent leakage of dust generated from the contents.

According to the granular storage tank 100 of this embodiment described above, the tank body is composed of one or more cylindrical bodies 30, and the cylindrical bodies 30 are connected at their ends in the circumferential direction and are composed of one or more outer wall members 50 that are curved in an arc shape in the circumferential direction by elastic deformation.
Therefore, the diameter and length of the tank body 10 can be easily changed by changing the number of cylindrical bodies 30 arranged in the vertical direction and the number of outer wall members 50 that make up the cylindrical bodies 30.
Furthermore, since the exterior wall member 50 is formed from a thin plate that can be elastically deformed to curve in an arc shape, material costs and processing costs can be reduced, and it is also highly convenient because it can be stacked and transported and stored from the processing plant to the installation site.
Furthermore, because the exterior wall member 50 is thin and lightweight, it can be easily assembled at the installation site.

Since the exterior wall members 50 are formed from thin, plate-like bodies that can be deformed to curve, there is no difficulty in finishing them to curve according to the diameter of the body, and material and processing costs can be suppressed. Furthermore, from the processing plant to the installation site, the exterior wall members 50 can be unfolded and stacked almost flat for transport and storage in a small volume, eliminating the waste associated with conventional tank transport, which is almost like transporting air. Assembly and disassembly can be done simply by operating connecting members such as bolts, making it highly convenient.

Because the outer wall members 50 are lightweight, assembly at the installation site is easy. Furthermore, the lowest end of the tank body 10, which is formed by combining multiple outer wall members 50, is connected to the upper end (lower connecting section 143) of the nearly perfectly circular conical lower hopper 14, or to a flat lower base plate (with a hatch on the bottom or side for mechanical removal). This naturally results in nearly perfect circular shapes, and the circular accuracy of the multi-tiered body also naturally becomes perfect when filled with contents. Therefore, the most difficult aspect of manufacturing—precise work to achieve a perfect circle—is completely unnecessary.

Furthermore, according to the granular material storage tank 100 and the assembly method of the granular material storage tank according to this embodiment, the side connecting portion 54, which is arranged vertically on the side surface of the tank body 10, acts as a reinforcing rib, and the connecting flange portion also acts as a reinforcing rib. Because the connection between the cylindrical bodies 30 is by insertion, it is easy to achieve a perfect circle, making it strong against load. In addition, the components are lighter and simpler, and there are no gaps in the connecting portion of the cylindrical bodies 30 that could allow contents to remain or insects to breed.

The extremely thin thickness of the plate-like material constituting the outer wall member 50 provides flexibility, allowing for the connection of the cylindrical bodies 30 by insertion when extending the length of the cylindrical granular material storage tank 100. This is because, conventional methods of connecting cylindrical bodies with flanges make it difficult to form a true cylinder, requiring a thicker steel plate to withstand the cylindrical load and uneven load. However, in this embodiment, where the cylindrical bodies 30 are connected by insertion, it is easy to form cylindrical bodies 30 with a true circular cross-section. This results in an outer wall member 50 that is equivalent to being formed from a single arc-shaped plate, preventing uneven load. In other words, just as an inflated balloon does not burst, the force is evenly distributed across the tank body 10 of the granular material storage tank 100.

The side connecting portion 54 not only acts as a reinforcing rib, but its cylindrical shape naturally provides greater structural strength than a flat surface. Combined with this, sufficient rigidity can be achieved even with an extremely thin steel plate constituting the exterior wall member 50.

The force exerted by the contents causing the tank body 10 to bulge outwards can mitigate the shear force caused by the load on the cylindrical bodies 30 at the connection points and the downward load from the contents. This also offers the advantage of requiring fewer fastening points at the connection points during assembly of the granular material storage tank 100.

Furthermore, the cylindrical granular storage tank 100, by adopting a cylindrical shape, is symmetrical from all angles when viewed from above, unlike a rectangular storage tank. It also lacks any so-called "corners" where contents could get trapped and remain. Therefore, the stored grains are supplied to the next process in a first-in, first-out manner when removed, and no grains remain as residue.

[Embodiment 2]
Next, a granular material storage tank 100A according to Embodiment 2 will be described. Figure 12 is a front view of the outer wall member 150 that constitutes the granular material storage tank 100A according to Embodiment 2 of the present invention.

In Embodiment 1, the side connecting portions 54, which are positioned at both ends of the outer wall member 50, are arranged in parallel. By changing the thickness of the spacer 64 interposed between the side connecting portions 54 when assembling the cylindrical body 30, the lengths of the inner and outer circumferential surfaces of the upper opening 311 and lower opening 312 of the first cylindrical body 31 were adjusted.

In Embodiment 2, the side connecting portions 154, which are positioned at both ends of the outer wall member 150, are made non-parallel. This allows for adjustment of the lengths of the inner and outer circumferential surfaces of the upper opening 311 and lower opening 312 of the first cylindrical body 31. The differences from Embodiment 1's granular storage tank 100 will be described below.

As shown in Figure 12, the side connecting portion 154 is a flange-shaped member positioned at both ends in the circumferential direction of the outer wall body 152. Similar to Embodiment 1, the side connecting portion 154 is integrally formed with the outer wall body 152 by bending a steel plate. The side connecting portion 154 is provided to connect the ends of the outer wall members 150. A reinforcing member 56 is attached to the side connecting portion 154. The reinforcing member 56 is attached to the outer wall body 152, for example, by spot welding. As the reinforcing member 56, for example, a steel material with an L-shaped cross-section can be used (see Figure 3).

The length of both ends of the exterior wall member 150 is formed such that the lower end L3 is slightly shorter than the upper end L2. Therefore, when the exterior wall member 150 is assembled into a cylindrical body, the diameter of the lower end is slightly smaller than the diameter of the upper end of the cylindrical body. This allows the bulge caused by the thickness of the exterior wall member to be compensated for even if the lower end of the upper cylindrical body is inserted inside the upper end of the lower cylindrical body.

In this way, by forming the side connecting portions 154 at both ends to be non-parallel and establishing a relative size relationship between the upper end spacing L2 and the lower end spacing L3, the same effect as changing the thickness of the spacer 64 described in Embodiment 1 can be obtained.

Furthermore, the exterior wall member 150 in this embodiment is made of thin steel plate. Therefore, the relative sizes of the upper end spacing L2 and the lower end spacing L3, which must be provided to allow the lower end of the first cylindrical body 31 (the end on the lower opening 312 side) to be inserted into the upper opening 321 of the second cylindrical body 32, are very small. For this reason, the relative sizes of the upper end spacing L2 and the lower end spacing L3 may be provided to all exterior wall members used in the assembly of the first cylindrical body 31 and the second cylindrical body 32, or they may be provided to only some of the exterior wall members.

In this embodiment, the lower L3 is formed to be slightly shorter than the upper L2. Therefore, when the outer wall member 150 is assembled into a cylindrical body, the diameter of the lower end of the cylindrical body is slightly smaller than the diameter of the upper end, resulting in a tapered shape. In this case, the lower end of the upper cylindrical body is inserted into the inside of the upper end of the lower cylindrical body to connect them. Alternatively, multiple cylindrical bodies can be connected by inserting the upper end of the lower cylindrical body into the inside of the lower end of the upper cylindrical body. In this case, when the outer wall member 150 is assembled into a cylindrical body, the diameter of the upper end of the cylindrical body must be slightly smaller than the diameter of the lower end, resulting in a tapered shape. To assemble the cylindrical body in this way, the outer wall member 150 of this embodiment can be used upside down. By using it upside down, the upper side (L3) becomes slightly shorter than the lower side (L2). By using the exterior wall member 150 upside down in this way, it becomes possible to connect the upper and lower cylindrical bodies using the same exterior wall member 150 in two ways: either by inserting the lower end of the upper cylindrical body into the inside of the upper end of the lower cylindrical body, or by inserting the upper end of the lower cylindrical body into the inside of the lower end of the upper cylindrical body.

[Embodiment 3]
Next, the granular material storage tank 100B according to Embodiment 3 will be described. Figure 13 is a perspective view showing the state in which the upper lid portion 12B is attached to the tank body 10 of the granular material storage tank 100B according to Embodiment 3. Embodiment 3 differs from Embodiment 1 in that the upper part of the tank body 10 is closed by the upper lid portion 12B which has a substantially frustoconical outer shape. The differences from the granular material storage tank 100 of Embodiment 1 will be described below.

As shown in Figure 13, the upper lid portion 12B has an upper lid main body 121B and an upper connecting portion 123. The upper lid main body 121B is formed by an inclined surface 122B having a predetermined inclination angle with respect to the horizontal plane. The upper lid main body 121B is formed in a circular shape in plan view. A granular material input opening 13B is provided in the center of the upper lid main body 121B. Therefore, the outer shape of the upper lid main body 121B is approximately a frustoconical shape.

The granular material inlet 13B also serves as a manhole, providing access for workers during maintenance of the tank body 10. A flange 131B is formed around the granular material inlet 13B. For example, a chute pipe 19 from an elevator that transports granular material PG is connected to the granular material inlet 13B and flange 131B (see Figure 14). The granular material PG supplied from the chute pipe 19 is then introduced into the tank body 10 via the granular material inlet 13B.

Figure 14 is a cross-sectional view showing the inclination angle θ1 of the inclined surface 122B of the upper lid portion 12B and the angle of repose θ2 of the granular PG stored in the granular storage tank 100B. Figure 15 is a cross-sectional view showing the movement of the surface of the granular PG when the granular PG stored in the granular storage tank 100B is discharged. As shown in Figure 14, the granular PG supplied from the chute piping 19 is stored inside the tank body 10. In this case, the upper part of the granular PG accumulates in a mountain-like shape so that the angle of the inclined surface relative to the horizontal plane has a predetermined inclination angle (angle of repose) θ2. The angle of repose θ2 varies depending on the type and size of the granular PG, but for example, if the granular PG is rice, the angle of repose θ2 is 33 to 34 degrees.

The angle θ1 of the inclined surface 122B of the upper lid portion 12B is set to correspond to the angle of repose θ2 of the granular PG. For example, it is preferable that the angle θ1 of the inclined surface 122B be set to be approximately 1 to 5 degrees greater than the angle of repose θ2 of the granular PG. For example, in this embodiment, since the angle of repose θ2 of the granular PG (rice) is 33 to 34 degrees, the inclination angle θ1 of the inclined surface 122B is set to 36 degrees.

In this case, as in Embodiment 1, when a flat upper lid 12 is provided on the top of the tank body 10, a space is created between the granular PG, which is accumulated in a curved shape according to the angle of repose θ2, and the flat upper lid 12. Since granular PG cannot be accumulated in this space, the space is wasted, and the steel plate of the tank body 10 that forms the area where granular PG cannot be accumulated is also wasted. Furthermore, granular PG dust may accumulate in the area where granular PG cannot be accumulated, potentially making the inside of the tank body 10 more susceptible to pest infestation.

In contrast, as in this third embodiment, by setting the inclination angle θ1 of the inclined surface 122B of the upper lid 12B to an angle corresponding to the accumulation shape of the granular PG (angle of repose θ2), a space is less likely to form between the granular PG and the upper lid 12B, as shown in Figure 15. This reduces wasted space and also reduces wasted steel plates constituting the tank body 10.

Furthermore, in this third embodiment, the inclination angle θ1 of the inclined surface 122B of the upper lid 12B is set to be slightly larger than the angle of repose θ2 of the granular PG. This creates an effect where, when the granular PG is removed, the granular PG moves while rubbing against the inner surface of the inclined surface 122B of the upper lid 12. Specifically, as shown in Figure 15, the surface S1 of the granular PG indicates the state where the granular PG has accumulated up to the top of the tank body 10. When the removal of granular PG from the lower hopper 14 of the tank body 10 begins in this state, the position of the surface of the granular PG gradually moves downward, as shown in S1, S2, S3, S4, etc., while maintaining the angle of repose θ2. In this case, at the point of contact between the inclined surface 122B of the upper lid 12B and the surface of the granular PG, the granular PG moves while rubbing against the inner surface of the inclined surface 122B. As a result, the granular PG moves while drawing in and removing dust particles attached to the inner surface of the inclined surface 122B, thus performing a cleaning function on the inner surface of the inclined surface 122B. Therefore, dust accumulation inside the tank body 10 can be suppressed, and the likelihood of pests breeding inside the tank body 10 is reduced.

[Variations]
The granular material storage tank according to the present invention is not limited to the embodiment described above. For example, the shape and dimensions of the main body are not limited to the shape of this embodiment.

In this embodiment, the outer wall member 50 constituting the tank body 10 has a constant thickness, but is not limited to this. For example, the thickness of the outer wall member 52 of the outer wall member 50 constituting the lowest cylindrical body 30 may be made thicker than the thickness of the outer wall member 52 of the other cylindrical body 30s. In this case, the strength of the lowest cylindrical body 30, which is subjected to particularly large loads, can be improved, and the strength of the tank body 10 can be improved.

In this embodiment, the exterior wall body 52 and the side connecting portion 54 of the exterior wall member 50 are formed integrally by bending both ends of a steel plate, but this is not limited to this. For example, the exterior wall body and the side connecting portion may be made as separate parts, the side connecting portion may be formed from an angle (L-shaped steel material), and the side connecting portion may be attached to the end of the flat exterior wall body by means of spot welding or other means. In this case, depending on the required strength and other conditions, the reinforcing material 56 described in the embodiment may be omitted.

The exterior wall member 50 may be configured to incorporate other parts as needed. For example, a mounting section for a sensor to detect the presence or absence of contents may be provided.

Examples of upper components include the upper lid 12 and upper lid 12B, and examples of lower components include the lower hopper 14 and lower base plate. However, the structure, shape, and material of these components are not particularly limited.

The embodiments of the present invention have been described above, but these embodiments are merely illustrative examples for carrying out the present invention. Therefore, the present invention is not limited to the embodiments described above, and it is possible to carry out the invention by appropriately modifying the embodiments described above without departing from the spirit of the invention.

100 Granular material storage tank 10 Tank body 30 Cylinder 31 First cylinder 32 Second cylinder 50 Outer wall member

Claims (5)

A granular material storage tank having a cylindrical tank body,
The tank body is
Each has an upper opening and a lower opening, and is composed of multiple cylindrical bodies arranged in the vertical direction.
The aforementioned cylindrical body is
It is composed of multiple outer wall members, each with its ends connected in the circumferential direction and curved in an arc shape in the circumferential direction by elastic deformation.
In a pair of vertically adjacent cylindrical bodies, the upper opening of the lower cylindrical body and the end of the lower opening of the upper cylindrical body are connected by being inserted into each other.
The aforementioned exterior wall member is
The outer wall body is formed of a plate-like body that is elastically deformable so as to be curved in an arc shape in the circumferential direction of the cylindrical body,
The cylindrical body has side connecting portions arranged at both ends of the outer wall body in the circumferential direction, which connect the ends of the outer wall members together.
It has,
The aforementioned side connecting portion is,
The ends of adjacent exterior wall members are connected so that adjacent exterior wall body parts do not overlap, and the side connecting parts are positioned at a predetermined distance from the upper or lower end of the cylindrical body so that when a pair of vertically adjacent cylindrical bodies are connected by insertion, the side connecting parts do not interfere with other cylindrical bodies.
Granular material storage tank. The tank body is equipped with a lower member connected to the lower part,
The lower member is formed as an inverted cone-shaped hopper or as a member with a circular top surface, and is connected to the lower part of the tank body.
The lower end of the tank body and the upper end of the lower member are connected by being inserted into each other.
A granular material storage tank according to claim 1. In a pair of cylindrical bodies connected vertically, the length of the inner circumference of the upper opening of the lower cylindrical body is made longer than the length of the outer circumference of the lower opening of the upper cylindrical body, or the length of the outer circumference of the upper opening of the lower cylindrical body is made shorter than the length of the inner circumference of the lower opening of the upper cylindrical body.
A granular material storage tank according to claim 1. The device further includes a fixing member for fixing the side connecting portion provided on the outer wall member constituting one of the vertically adjacent cylindrical bodies, and the side connecting portion provided on the outer wall member constituting the other cylindrical body.
A granular material storage tank according to any one of claims 1 to 3. A method for assembling a granular storage tank according to claim 2 ,
The tank body is composed of multiple cylindrical bodies,
The multiple outer wall members constituting the cylindrical body are connectable at their ends in the circumferential direction of the tank body, and are also capable of bending in an arc shape in the circumferential direction by elastic deformation.
A cylindrical assembly step in which multiple outer wall members are elastically deformed in the circumferential direction, the ends of the outer wall members are connected to form a cylindrical body, and the tank body is formed by multiple cylindrical bodies,
A lower connection step involves connecting the inverted cone-shaped hopper, or the lower member having a circular top surface, to the lower part of the tank body by insertion,
A method for assembling a granular storage tank containing [a specific material].