JP2018167841A - Cylindrical tank - Google Patents

Abstract

To provide a frame for restricting a tank body of a cylindrical tank deforming toward the radial direction in order to restrain bulging vibrations occurring inside the tank body.SOLUTION: A reinforcement frame 1 is arranged inside a tank body 4 of a cylindrical tank 2, which is made of a torus-shaped sealed pipe filled with air and is placed along the internal surface of the tank body with a small clearance. The reinforcement frame 1 is moored to tank base points 33 nearby the bottom, and the buoyant force of the reinforcement frame and the reactive force of the moor are in equilibrium to place the frame at almost the middle height of the tank body. In the case of bulging deformation occurring in the tank body, the internal surface of the tank body contacts the reinforcement frame.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a cylindrical tank.

  Cylindrical tanks that store water and fuel oil are required to maintain a self-supporting state without collapsing and to prevent leakage even when an earthquake occurs. Damage modes assumed when an earthquake is applied to a cylindrical tank include buckling of an elbow foot near the lower end of the tank body, and measures have been taken conventionally. A method for reinforcing these damage modes is disclosed in Patent Document 1, for example.

  In Patent Document 1, with respect to a predetermined height portion including a portion where a buckling deformation is likely to occur due to an earthquake on a side plate of a flat bottom cylindrical steel tank, a support frame body that is spaced apart and installed at a predetermined width position, It is described that the reinforcement is formed with a PC steel wire that is stretched inside and / or on the outer peripheral surface of the support frame, and concrete that is continuously placed inside the support frame.

JP 2012-250712 A

  Patent Document 1 describes a countermeasure against elbow leg buckling, for example. The reinforcing structure described in Patent Document 1 is effective for reinforcing the vicinity of the bottom of the cylindrical tank.

  On the other hand, when an earthquake acts on a cylindrical tank that stores liquid, the amplitude increases at half the height of the cylinder tank's shell plate, and a bulging mode that vibrates like a petal in the horizontal section of the drum plate oscillates. May be excited.

  For example, in order to apply the reinforcement method using concrete or the like to a high position as in Patent Document 1, it is necessary to increase the thickness of the concrete near the bottom surface in order to support the reinforcing member at a high position from the bottom surface, and the construction cost The increase in the area and the increase in the installation area are issues.

  An object of the present invention is to provide a cylindrical tank and a cylindrical tank reinforcing method in which a bulging mode is suppressed by a simple and lightweight reinforcing structure.

  In order to solve the above-mentioned problems, one of the typical cylindrical tanks of the present invention is a cylindrical tank for storing liquid, and has an annular reinforcement that extends along the inner wall surface of the cylindrical tank with a small gap. A frame, a restraint device having one end connected to the reinforcing frame, and a lower end of the cylindrical tank, the reinforcing frame being stopped at a position approximately half the height of the tank body in the cylindrical tank. And a connecting jig for connecting the other end of the restraining device.

  According to the present invention, bulging deformation of a cylindrical tank can be suppressed by a simple and lightweight reinforcing structure.

It is a schematic longitudinal cross-sectional view of the cylindrical tank to which the reinforcement frame in Example 1 is applied. It is a schematic bird's-eye view which made some cross sections of the cylindrical tank to which the reinforcement frame in Example 2 was applied. It is a schematic longitudinal cross-sectional view of the cylindrical tank to which the reinforcement frame by Example 2 is applied. It is a schematic longitudinal cross-sectional view of the cylindrical tank to which the reinforcement frame by Example 3 is applied. It is a schematic longitudinal cross-sectional view of the cylindrical tank to which the reinforcement frame by Example 4 is applied.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view of a cylindrical tank to which a reinforcing frame in Example 1 is applied. Here, the cylindrical tank 2 to which the reinforcing frame 1 is applied is defined. The cylindrical tank 2 includes a tank body 4 that is firmly attached to a strong foundation 3 connected to the ground by a plurality of circumferentially set gusset plates 33. The tank body 4 is thicker at the bottom and has a roof at the top. 5 is attached and can store the liquid 10.

  The reinforcing frame 1 according to the first embodiment is a torus-shaped reinforcing frame, and is integrally formed of a highly rigid material such as CFRP (carbon fiber reinforced plastic). The reinforcing frame 1 alone has high rigidity, and maintains the torus shape independently even when a load is applied inward in the radial direction of the tank body. The reinforcing frame 1 is hollow and has a sealed structure, and has a buoyancy with respect to the liquid 10 by enclosing a gas such as nitrogen therein.

  The reinforcing frame 1 is connected to the inside of the position where the gusset plate 33 is welded to the outside of the tank body 4 by a chain 6 having a length approximately half the height of the tank body 4. When the forces are balanced, the amplitude of the bulging deformation is increased and the tank body 4 is positioned approximately in the center of the height, and the reinforcing frame 1 and the inner wall surface of the tank body 4 are submerged in the liquid with a gap. Yes.

  If there is the reinforcing frame 1 in such a state, when the bulging deformation occurs, the inner wall surface of the tank body deforming inward and the reinforcing frame 1 come into contact. Since the reinforcing frame 1 has high rigidity with respect to the radial direction of the tank cylinder 4, the tank cylinder 4 cannot be deformed further inward when it comes into contact with the reinforcing frame 1. In this way, the reinforcing frame 1 exhibits the effect of preventing the tank barrel 4 from bulging and deforming with an amplitude greater than the gap between the reinforcing frame 1 and the tank barrel 4.

  Next, the relationship between the position of the liquid level and the effect of the reinforcing frame 1 will be described. When the liquid level is above the center position of the height of the tank body 4, the reinforcing frame 1 is positioned at the center of the height of the tank body 4, and the position where the amplitude of the bulging deformation increases is also the tank body. Since the height does not drop from the approximate center position of the height of 4, there is no change in the effect of the reinforcing frame 1 preventing bulging.

  When the liquid level is lowered from a position approximately at the center of the height of the tank body 4, the reinforcing frame 1 is exposed to the liquid level, the position of the reinforcing frame 1 is also lowered together with the liquid level, and the amplitude of bulging deformation increases. The position may be higher than the position of the reinforcing frame 1. At this time, if the liquid level is sufficiently low, the load that the liquid 10 acts on the tank body 4 due to the earthquake is small, and it is not necessary to prevent bulging. Even if the reinforcing frame 1 is exposed to the liquid level, the effect of the reinforcing frame 1 preventing bulging is not changed as long as the liquid level is near the center of the height of the tank body 4.

  From the above, the effect of the reinforcing frame 1 preventing bulging deformation does not depend on the position of the liquid surface.

  In this embodiment, the bulging mode is suppressed by installing a simple and lightweight reinforcing frame 1 on the inner side of the center of the height of the tank body 4. Since the reinforcing frame 1 stays at approximately the center of the height of the tank body 4 due to buoyancy, it is not necessary to support the base 3 and the bulging deformation of the cylindrical tank 2 can be suppressed by a simple and lightweight reinforcing structure.

  FIG. 2 is a schematic bird's-eye view of a cross section of a part of a cylindrical tank to which the reinforcing frame in the second embodiment is applied. FIG. 3 is a schematic longitudinal sectional view of a cylindrical tank to which the reinforcing frame in the second embodiment is applied. Since the cylindrical tank 2 to which the reinforcing frame 1 is applied is the same as the example shown in FIG. 1, the illustration and detailed description thereof are omitted.

  In Example 1, a highly rigid torus-like frame capable of maintaining the shape independently was used, but in Example 2, this was changed to a structure that can be carried into the cylindrical tank 2 in a divided state.

  In the second embodiment, as the material of the reinforcing frame 1, for example, a stainless steel pipe having an inner shape and an outer surface coated with resin and having an end shape inserted into each other is used. By joining a plurality of arc-shaped pipes along the tank body 4 using an adhesive in a cylindrical tank, the torus-shaped frame 11 can be easily constructed, and a reinforcing frame can be applied to an existing cylindrical tank. Similar to the first embodiment, a gas such as nitrogen is sealed inside to have buoyancy with respect to the liquid 10.

  In the first embodiment, the reinforcing frame 1 is configured by only the torus-shaped reinforcing frame, whereas in the second embodiment, the torus-shaped frame 11 includes the spokes 7. The spoke 7 is a rod-shaped structure installed in the radial direction of the tank body with a gap between the upward and downward conical surfaces. The spokes 7 gather at the upper and lower sides in the center of the tank body 4, and the two upper and lower points gathered are connected to a hub 8 that is a thin cylindrical structure concentric with the tank body 4. The spokes 7 are provided with turnbuckles 71 in the middle, the lengths of which can be finely adjusted, and approximately equal tensile forces are applied to each other. As an effect, the circular shape of the reinforcing frame 1 can be finely adjusted, and the rigidity in the radial direction can be enhanced.

  The plate thickness and cross-sectional shape of the torus-shaped frame 11 are created so that the reinforcing frame 1 has buoyancy with respect to the liquid 10. The mechanism and the effect that the reinforcing frame 1 is located in the liquid in a state where the reinforcing frame 1 is positioned approximately at the center of the height of the tank cylinder 4 and the reinforcing frame 1 and the inner wall surface of the tank cylinder 4 have a gap are the same as in the first embodiment. It is.

  In the present embodiment, in addition to the effects of the first embodiment, it is possible to additionally install the reinforcing frame 1 in the existing cylindrical tank 2, and a method for reinforcing the existing cylindrical tank 2 can be realized.

  FIG. 4 is a schematic longitudinal sectional view of a cylindrical tank 2 to which the reinforcing frame 1 in the third embodiment is applied. Since the cylindrical tank 2 to which the reinforcing frame 1 is applied is the same as the example shown in FIG.

  In the first embodiment and the second embodiment, there is one torus-shaped frame. However, in the reinforcing frame 1 according to the third embodiment, there are two torus-shaped frames, and the tank can be used even when the reinforcing frame is inclined. By contacting the trunk and the reinforcing frame, there is an effect of preventing the reinforcing frame 1 from being inclined with respect to the bottom surface.

  The reinforcement frame 1 is connected to the inside of the position where the gusset plate 33 is welded to the outside of the tank body 4 by the chain 6, and the buoyancy of the reinforcement frame 1 and the reaction force of the chain balance, thereby increasing the amplitude of bulging deformation. The upper torus-shaped frame 11a is positioned approximately at the center of the height of the tank body 4, and the reinforcing frame 1 and the inner wall surface of the tank body are submerged in the liquid with a gap. The mechanism and effect of the reinforcing frame 1 preventing bulging deformation are the same as in the first embodiment.

  The torus-shaped frame is formed by welding divided metal pipes in a cylindrical tank, and in the same manner as in the first and second embodiments, a gas such as nitrogen is sealed inside to provide buoyancy to the liquid 10. Have. The upper torus-shaped frame 11a and the lower torus-shaped frame 11b are connected by a support pipe 9 installed in the height direction so as to be parallel to each other. A pipe is welded as a spoke 7 in the radial direction of the tank body 4 to a conical surface facing upward from the lower torus-shaped frame 11b and downward from the upper torus-shaped frame 11a. The spokes 7 gather at the upper and lower ends of the hub 8 at the center of the tank body 4, and the length can be finely adjusted by the turnbuckle 71. The mechanism and effect of the spoke 7 are the same as in the second embodiment.

  In the present embodiment, in addition to the effects of the first and second embodiments, there is an effect of preventing the reinforcement frame from being inclined with respect to the bottom surface.

FIG. 5 is a schematic longitudinal sectional view of a cylindrical tank to which the reinforcing frame 1 in the fourth embodiment is applied.
Since the cylindrical tank 2 to which the reinforcing frame 1 is applied is the same as the example shown in FIG. 1, the illustration and detailed description thereof are omitted.

  In the first to third embodiments, the reinforcing frame 1 was entirely in the liquid, but in the reinforcing frame 1 according to the fourth embodiment, the torus shape connected by the column pipes 9 installed in the height direction so as to be parallel to each other. The reinforcing frame 1 has a gusset plate 33 welded to the outside of the tank body 4 so that the uppermost torus-shaped frame 11a is positioned above the liquid level and up to the upper end of the tank body 4. The chain 6 is connected to the inside of the existing position.

  A state in which the central torus-shaped frame 11c is positioned approximately at the center of the height of the tank body 4 where the amplitude of bulging deformation increases, and there is a gap between the reinforcing frame 1 and the inner wall surface of the tank body. It is sinking. The mechanism and effect of the reinforcing frame 1 preventing bulging deformation are the same as in the first embodiment.

  The mechanism and effect for preventing the reinforcement frame 1 from being inclined with respect to the bottom surface are the same as in the third embodiment. Even when the liquid level is shaken, the upper torus-shaped frame 11a, the central torus-shaped frame 11c, The lower torus-shaped frame 11b maintains a state substantially parallel to the bottom surface.

  When sloshing occurs in the cylindrical tank 2, a part of the liquid flowing upward along the tank body 4 collides with the upper torus-shaped frame 11 a located above the liquid surface, forcing the flow direction. Will be changed. Since the ratio of the liquid flowing upward along the tank body 4 and colliding with the roof 5 is reduced by the upper torus-shaped frame 11a, the reinforcing frame 1 reduces the pressure acting on the roof and the moment acting on the upper end, respectively. To do. Therefore, the reinforcing frame 1 exhibits three effects of preventing damage to the roof and preventing buckling of the tank body 4 in addition to preventing bulging deformation.

  The torus-shaped frame 11 is provided with spokes 7 as in the second embodiment, and the mechanism and effects of the spokes 7 are the same as in the second embodiment.

  In the present embodiment, in addition to the effects of the first to third embodiments, there is an effect of preventing damage to the roof and buckling of the elbow leg of the tank body 4.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

1: Reinforcement frame 2: Cylindrical tank 3: Foundation 4: Tank body 5: Roof 6: Chain 7: Spoke 8: Hub 9: Support pipe 10: Liquid 11: Torus-shaped frame 11a: Torus-shaped frame 11b: Lower torus-shaped frame 11c: central torus-shaped frame 33: gusset plate 71: turnbuckle

Claims (6)

A cylindrical tank for storing liquid,
An annular reinforcing frame that extends along the inner wall surface of the cylindrical tank with a small gap;
In the cylindrical tank, at a position approximately half the height of the tank body, the reinforcing frame is stopped, and a restraint device having one end connected to the reinforcing frame;
A connecting jig for connecting the other end of the restraining device at the bottom of the cylindrical tank;
A cylindrical tank characterized by comprising: The cylindrical tank according to claim 1,
The reinforcing frame includes a plurality of annular reinforcing frames along the inner wall surface of the tank body,
A cylindrical tank comprising a support structure that supports the plurality of annular reinforcing frames. In the cylindrical tank according to claim 1 or 2,
The reinforcing frame includes a plurality of annular reinforcing frames along the inner wall surface of the tank body,
A hub located in the center of the plurality of annular reinforcing frames;
A cylindrical tank comprising a spoke connecting the reinforcing frame and the hub. In the cylindrical tank according to claim 3,
A cylindrical tank characterized in that the spoke has an adjusting device capable of adjusting its length. In the cylindrical tank in any one of Claims 2-4,
At least one of a plurality of annular reinforcing frames is located above the liquid in the cylindrical tank. In the cylindrical tank in any one of Claims 1-5,
The cylindrical tank is characterized in that the reinforcing frame is hollow and has a sealed structure.

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