JP4895650B2 - Seismic isolation device and floating roof tank - Google Patents

Description

  The present invention relates to a seismic isolation device for suppressing occurrence of sloshing in a container having a floating roof and a floating roof type tank including the seismic isolation device.

  As a tank for storing a gas such as natural gas or a liquid such as water, petroleum, or a chemical, a spherical holder, a fixed roof tank, a floating roof tank, or the like is used. Of these gases and liquids, floating roof tanks are often used as tanks for storing volatile liquids such as petroleum. This is because the floating roof covers the liquid level and floats up and down freely, and no space is created between the floating roof and the liquid level regardless of the position of the liquid level. This is because the liquid loss can be suppressed. When the liquid volatilizes, the amount of liquid in the tank decreases and the amount of liquid used decreases.

  Here, the structure of the floating roof type tank will be described. Generally, it is composed of a circular bottom plate, a side plate constructed in a hollow cylindrical shape for storing liquid, and a floating roof that covers the liquid surface and floats on the liquid surface. The reason why the side plate is constructed in the shape of a hollow cylinder is that the pressure applied to the side plate by the liquid stored in the inside is made almost uniform and the tank is hardly damaged. The floating roof is composed of a deck plate that covers the center of the liquid surface and a pontoon that is a hollow box-shaped structure provided around the deck plate and floats on the liquid surface. A slight gap exists between the pontoon and the side plate of the tank. However, by providing a seal member around the pontoon and filling the gap with the seal member, the volatilization of the liquid can be suppressed. The floating roof is used while floating on the liquid surface, and rises as the liquid level rises as the liquid is supplied, and falls as the liquid level falls as the liquid is taken out.

  When an earthquake occurs, ground motion occurs around the epicenter, and this ground motion is transmitted to this floating roof tank. This seismic motion causes the tank to swing, and this swing is transmitted to the liquid in the tank. When the period due to seismic motion and the natural period of the tank overlap and a resonance occurs, a phenomenon called sloshing, in which the liquid surface greatly swells due to this resonance, occurs.

  This sloshing continues even if the earthquake stops, causing a rotational motion on the floating roof and increasing the wave height. This increase in wave height may cause the tank contents to overflow, and may cause negative pressure and positive pressure between the floating roof and the liquid level to break the floating roof. Since the vibration of sloshing is not transmitted to the ground or the like, there is no place to diverge and it continues for a long time. If the tank contents are a flammable liquid such as oil, the flammable liquid will continue to overflow and a fire will continue, causing a catastrophe. For this reason, floating roof tanks are designed to provide resistance to liquid movement in the tank during an earthquake or to fix floating roofs to attenuate sloshing vibrations and to suppress sloshing. The device is provided.

  In high-rise condominiums, detached houses, etc., when building a building, a seismic isolation device is installed or a seismic isolation structure is constructed to attenuate the shaking of the upper building. In recent years, many seismic isolation devices have been proposed due to the increase in earthquakes and the growing interest in future earthquakes.

  In general, seismic isolation devices are used to reduce vibrations by installing many dampers and stoppers. However, since they are installed at remote locations, the construction period is greatly extended, and the cost is high, so replacement work is required. Therefore, a seismic isolation device using a sphere as a constituent element has been proposed (see, for example, Patent Documents 1 and 2). This seismic isolation device is composed of a lower support plate fixed to the ground side, a sphere that is movably mounted on the lower support plate, and a lower support plate that is fixed to the upper structure side. An upper support plate that sandwiches the ring, a ring-shaped stopper formed on both the upper and lower support plates, and a ring-shaped shock absorber made of rubber or the like that is fixed to the inner peripheral surface of the stopper portion. It is supposed to be.

  Since the structure including the seismic isolation device is supported by a sphere, even if the ground shakes due to the earthquake, the sphere rolls and moves, thereby reducing the shaking of the structure. This seismic isolation device is provided with a ring-shaped stopper so that the structure on the sphere does not fall off the sphere, so that the sphere contacts the stopper and the impact is transmitted to the structure. And a ring-shaped shock absorber.

  In addition, a structure in which a sphere is sandwiched between the upper support plate and the lower support plate is supported so as to be able to roll, and a damping element and a restoring element are provided so as to connect the upper support plate and the lower support portion. There has also been proposed a seismic isolation device that enables slipping and can restore the rolling movement range to a neutral position (see Patent Document 3). This seismic isolation device keeps the resonance frequency low and constant regardless of the magnitude of the amplitude, attenuates the impact of the earthquake without placing higher-order vibration components, and provides stable damping performance coupled with shortening the convergence time. It can be surely demonstrated.

  These seismic isolation devices reduce the seismic force acting on the structure by lengthening the natural period of the structure, and use a device having a damping force such as an absorber together with the structure. It absorbs vibration energy. Therefore, if these seismic isolation devices are installed in a floating roof type tank, the natural period of the tank is lengthened so that resonance is not generated, and the vibration energy of the tank can be absorbed by an absorber, etc. It is considered that sloshing can be suppressed.

However, it is difficult to attach the plurality of seismic isolation devices to the predetermined positions on the bottom surface of the wide tank, and it is necessary to align the positions of the seismic isolation devices. Therefore, depending on the vibration energy of the tank, there is a problem that the sphere exceeds the stopper part and the upper part of the absorber and comes off. In addition, since the sphere directly collides with the absorber, there is also a problem that vibration energy cannot be sufficiently absorbed. Therefore, it is desired to provide a seismic isolation device for a floating roof tank that is easy to install, does not need to be aligned, and can reliably and sufficiently absorb vibration energy and suppress the occurrence of sloshing. .
Japanese Patent No. 2968260 Japanese Patent No. 3174860 JP 11-315886 A

  The present invention has been made to solve the above-described problems, and is easy to install, does not need to be aligned, and can absorb vibration energy reliably and sufficiently to suppress the occurrence of sloshing. It aims at providing a floating roof type tank provided with a seismic device and this seismic isolation device.

  The above-mentioned subject is achieved by providing the seismic isolation device of the present invention and a floating roof type tank provided with the seismic isolation device. That is, according to the present invention, a plurality of spheres arranged between the bottom plate of the container and the flat ground or foundation and movably supporting the container, and a vertical direction from the ground or foundation so as to surround the circumference of the container. A seismic isolation device is provided that includes a stopper that extends and is constructed on the ground or foundation, and a shock absorber provided on both the outer wall and the stopper of the container so as to face each other.

  The container is a cylindrical container having an inner diameter L, and the distance between the outer wall of the container and the stopper is shorter than 0.25L.

  The stopper forms an accommodating portion for accommodating the container, and water is stored in the accommodating portion in which the container is accommodated.

  The cushioning material is a ring-shaped damper, which absorbs vibration energy of the container and suppresses overflow of water stored in the housing portion.

  Each of the plurality of spheres includes a plurality of holes that can be inserted and spaced apart from each other, and further includes a plate member smaller than the outer diameter of the container, and a connector for connecting the plate member to the ground or the foundation. Each of the plurality of spheres is rotatably inserted in each of the plurality of holes.

In this invention, a floating roof type tank provided with the said seismic isolation apparatus can also be provided. The floating roof type tank includes a container for storing liquid, a floating roof that floats on the liquid surface and covers the liquid surface,
Including the seismic isolation device.

  By providing the seismic isolation device and the floating roof type tank of the present invention, it is easy to install and does not need to be aligned, and it is possible to absorb vibration energy reliably and sufficiently to suppress the occurrence of sloshing. Moreover, even if the liquid overflows from the container, it can be prevented from flowing out to the surrounding soil or river. Furthermore, by storing water in the container, vibration energy can be absorbed more effectively, and the digestion water and tank when the flammable liquid in the container burns are cooled, and the liquid is volatilized. It can also be used as a cooling medium that suppresses the above. Moreover, by setting it as the structure provided with a plate member and a connection tool, the position of each spherical body is fixed, a container is supported reliably, and the seismic force which acts on a container can be reduced reliably.

  The seismic isolation device of the present invention will be described in detail with reference to the drawings. Drawing 1 is a figure showing a 1st embodiment of a floating roof type tank provided with a seismic isolation device. FIG. 2 is a plan view thereof. Hereinafter, this embodiment will be described with reference to FIGS. 1 and 2. As described above, the floating roof type tank includes a main body composed of the bottom plate 10a and the side plate 10b, a floating roof 11 composed of a deck plate and a pontoon, a plurality of spheres 12, a stopper 13, and a cushioning material 14. And a seismic isolation device 15 composed of

  The bottom plate 10a, the side plate 10b, and the deck plate are generally made of steel, and the pontoon is made hollow so as to float on the liquid surface, and is made of plastic material such as polyvinyl chloride or fiber reinforced plastic (FRP), or concrete. . The main body of the tank is generally cylindrical so that the pressure received from the liquid stored in the tank is evenly applied. For this reason, the floating roof 11 has a circular deck plate, and a plurality of pontoons are provided around the circular deck plate, and has a circular shape as shown in the plan view of FIG. The liquid stored inside is flammable liquid such as petroleum, heavy oil, gasoline, water, liquid chemicals, and the like. This flammable liquid flows out of the container, and if an ignition source exists outside the spilled container, a fire is generated. In addition, when liquid chemicals flow out of the container and penetrate into the soil or river, depending on the substance, the soil or river is contaminated. These liquids do not swell and escape from the container in normal times without earthquakes. However, when an earthquake occurs, sloshing where the liquid level greatly swells, and these liquids may flow out. In the present invention, the vibration energy given to the container by the seismic isolation device 15 can be reduced to suppress the undulation of the liquid surface, and these liquids can be prevented from flowing out of the container. Hereinafter, the seismic isolation device 15 will be described.

  The plurality of spheres 12 constituting the seismic isolation device 15 are disposed between the bottom plate 10a of the container and the flat ground or the foundation 16, and support the container in a movable manner. The plurality of spheres 12 rotate so as to maintain the container at the position before the occurrence of the earthquake even if the ground or the foundation 16 swings at the time of the earthquake, thereby reducing the vibration energy acting on the container. Thereby, the vibrational energy acting on the liquid in the container is also reduced, and the liquid surface is also prevented from ripples. Incidentally, when the ground or the foundation 16 is considered as a reference, the container appears to move in a predetermined direction by the rotation of the plurality of spheres 12. Here, the foundation can be a lower structure including a flat surface formed by placing concrete on the ground, for example.

  The sphere 12 is made of steel and is made of a material such as steel or ceramic having a strength capable of supporting a container in which a liquid is stored. The diameter may be any diameter as long as the container can be appropriately rotated and moved, for example, 0.01 m to 0.1 m. The spherical body 12 can be made of hard rubber, but since the container containing the liquid has a large mass, the hard rubber is easily deformed, and when deformed, it becomes difficult to rotate, and the container can be moved smoothly. The above materials are preferred because they are eliminated. The arrangement of the individual spheres 12 may be dense as long as they can be rotated smoothly, but it is preferable that the individual spheres 12 be spaced apart from each other so that they can be rotated appropriately.

  The stopper 13 is spaced apart so as to surround the periphery of the container, extends vertically from the ground or foundation 16, and is constructed on the ground or foundation 16. For example, it can be constructed of steel plate or concrete. The stopper 13 is preferably constructed such that the distance from the container is shorter than 0.25 L, where L is the inner diameter of the container. When sloshing occurs, the sloshing wavelength is 2L. Even if the earthquake stops and the rocking of the ground or the foundation 16 stops, since the container is supported by the sphere 12 in the present invention, the container continues to reciprocate between the stoppers 13 and vibration energy is applied to the container. . For example, when the distance between the stopper 13 and the container is 0.4 L, the distance from the stopper on the other side is 0.8 L when the container is in contact with the stopper 13 on one side by the reciprocating motion. ing. Then, the distance between the stoppers 13 is 1.8 L, which is close to the sloshing wavelength, and resonance may occur. In addition, long-wave waves are difficult to attenuate. Therefore, by making the length shorter than 0.25 L as described above, resonance can be prevented and waves can be easily attenuated.

  As shown in the plan view of FIG. 2, the stopper 13 is constructed at a predetermined height so as to surround the circumference of the circular container. For this reason, the stopper 13 forms an accommodating portion for accommodating the container. Further, the stopper 13 has a thickness r having a strength capable of stopping the container moved by the rotation of the plurality of spheres 12. The height of the stopper 13 is set to a height at which the movement of the container can be stopped. When the container installed on the sphere 12 moves, at least the height at which the outer wall of the container collides with the outer wall is provided. It is set as the height which can provide the shock absorbing material 14 facing. Therefore, if the height of the outer wall of the container collides with, for example, 1 cm higher than the diameter of the sphere 12, the container can be made to collide, but since the cushioning material 14 cannot be provided facing the outer wall, the sphere When the diameter of 12 is about 0.1 m and the height of the container is about 10 m, for example, the height can be about 1 m to about 3 m.

  In the above, the construction of the stopper 13 on the ground or the foundation 16 has been described. However, in the present invention, a groove is formed in the ground, or a recess in the ground is used, and the side wall of the ground of the groove, or The side wall of the ground of the recess can be formed and used as a stopper. In this case, the bottom surface of the groove or the recess may be left as it is, but it may be formed flat by placing concrete or the like, constructed as a side wall having a predetermined strength, and disposed with the cushioning material 14. it can.

  The cushioning material 14 is provided on both the outer wall of the container and the stopper 13 so as to face each other. The cushioning material 14 reduces the energy when the container collides with the stopper 13 and reduces the energy given to the liquid inside. When only the energy at the time of the collision is reduced, it is sufficient that the buffer material 14 is provided on either the outer wall of the container or the stopper 13, but the side plate 10b constituting the outer wall of the floating roof type tank. Is about 0.05 m thin and easily damaged, and when the stopper 13 is made of concrete, it is easily broken by the collision of a steel container, so both the outer wall of the container and the stopper 13 Are provided so as to face each other.

  The cushioning material 14 is provided at a predetermined height position of the outer wall on the lower side of the container and the stopper 13 facing it, and as shown in FIG. More preferably, it is provided. An example of the cushioning material 14 is a damper. As the damper, an elastic body such as a spring or rubber can be used. In addition, a shape can be made into a ring shape, when providing in the inner periphery of the stopper 13 in the said outer wall periphery. Other shapes and structures may be any shape and structure known so far.

  The suppression of sloshing by the seismic isolation device 15 will be described in detail with reference to FIG. When an earthquake occurs and vibration energy acts in the direction indicated by the arrow A, the ground or the foundation 16 moves in the direction indicated by the arrow A. As the ground or base 16 moves, the stopper 13 also moves. On the other hand, the inertia force which continues to remain in the position before the occurrence of the earthquake acts on the container 17. For this reason, the plurality of spheres 12 interposed between the ground or foundation 16 and the container 17 rotate, and try to maintain the position of the container 17 while moving the ground or foundation 16. As the ground or foundation 16 moves, the stopper 13a approaches the container 17, and then the cushioning material 14a provided on the outer wall of the container 17 and the cushioning material 14b provided on the stopper 13a facing the cushioning material 14a. And clash. Although the vibration energy due to the earthquake is transmitted to the container 17 due to this collision, the vibration energy is absorbed by the mutual buffer materials 14a and 14b, so that the reduced vibration energy is transmitted to the container 17.

  Subsequently, the vibration energy acts in the direction opposite to the arrow A due to the rocking of the ground or the foundation 16 due to the earthquake. In this case, the plurality of spheres 12 rotate in the direction opposite to the above, and the stopper 13 b facing the stopper 13 a via the container 17 approaches the container 17. Thereafter, the shock absorbing material 14c provided on the outer wall of the container 17 collides with the shock absorbing material 14d provided on the stopper 13b so as to face the shock absorbing material 14c. Since the vibration energy is also absorbed by the buffer materials 14c and 14d, the reduced energy is transmitted to the container 17. Since the ground or foundation 16 swings due to the earthquake, the seismic isolation device 15 repeats such an operation.

  In the container 17, the reduced vibration energy acts on the liquid repeatedly, and vibration energy is given to the liquid. The vibration period of the vibration energy is lengthened by the rotation of the sphere 12 and is longer than the period of the seismic wave. For this reason, generation | occurrence | production of resonance can be suppressed and generation | occurrence | production of sloshing is suppressed.

  FIG. 4 is a diagram showing a second embodiment of the seismic isolation device. The seismic isolation device shown in FIG. 4 has the same configuration as the seismic isolation device 15 shown in FIG. 1, but water 19 is stored in the accommodating portion 18 formed by the stopper 13. Further, the buffer material 14 is a ring-shaped damper that absorbs the vibration energy of the container 17 and suppresses the overflow of the water 19 stored in the accommodating portion 18.

  For example, a container 17 having a height of about 10 m is installed on a sphere 12 having a diameter of about 0.1 m, and a stopper 13 having a height of about 3 m is constructed around the container 17, and the outer wall of the container 17 and the height inside the stopper 13 are set. It is assumed that the cushioning material 14 is provided at a position of about 2.5 m so as to face each other. In this case, the water 19 can be stored up to a height of about 2 m. This water 19 can give resistance to the movement of the stopper 13 to the container 17 due to the rotation of the sphere 12. Thereby, the vibration energy which acts on the container 17 can be further reduced.

  The water 19 reduces vibration energy acting on the container 17 as described above, and the liquid in the container 17 is a flammable liquid. If a fire occurs due to the presence of any ignition source, the water 19 is used as fire extinguishing water. Can be used. It can also be used as a cooling medium for suppressing the volatilization of the liquid in the container 17. In addition, when stored over a long period of time, aquatic or the like is generated, so that it can be appropriately replaced.

  FIG. 5 is a diagram showing a third embodiment of the seismic isolation device. The seismic isolation device shown in FIG. 5 (a) is further provided with a plurality of holes 20 into which the plurality of spheres 12 can be inserted and spaced apart from the seismic isolation device shown in FIG. A plate member 21 having a smaller diameter and a connector 22 for connecting the plate member 21 to the ground or foundation 16 while being separated from the ground or foundation 16 are configured. In this seismic isolation device, as shown in FIG. 5B, each of the plurality of spheres 12 is rotatably inserted in each of the plurality of holes 20 provided in the plate member 21. FIG. 5B illustrates a plan view of the plate member 21 and does not correspond to the cross-sectional view of the plate member shown in FIG.

  In the seismic isolation device shown in FIG. 1, a plurality of spheres 12 are randomly arranged, and the spheres 12 may be brought into close contact with each other or gathered at a predetermined location due to the rotation of the spheres 12. When in close contact with each other in this way, it becomes difficult to rotate and hinders smooth movement. Moreover, if it gathers in a predetermined location, it will become impossible to support the container 17. FIG. This gives vibration energy directly to the container 17 and propagates to the liquid, causing sloshing. For this reason, it is preferable that the spherical body 12 is maintained in a state of being separated from each other. In order to maintain this state, the plate member 21 and the connector 22 shown in FIG. 5 can be used.

  The plate member 21 includes a plurality of holes 20 through which each of the plurality of spheres 12 can be inserted and separated from each other. The sphere 12 is inserted into the hole 20. Therefore, the diameter of the hole 20 is formed larger than the diameter of the sphere 12. The plate member 21 is made smaller than the outer diameter of the container 17 so that the stopper 13 and the plate member 21 do not collide before the buffer materials 14 collide with each other. The plate member 21 is perforated at an appropriate size and in an appropriate size with a number corresponding to the number of the spheres 12 in order to appropriately support and move the container 17 with the plurality of spheres 12. However, since the plate member 21 supports the container 17 by the sphere 12, the plate member 21 has a thickness smaller than the diameter of the sphere 12 so that the sphere 12 is adjacent to the container 17 and the ground or the foundation 16.

  The connector 22 connects the plate member 21 to the ground or the foundation 16. Therefore, any member can be used as long as the plate member 21 can be connected. When the connector 22 is a bolt, the diameter of the sphere 12 is about 0.1 m, and the plate member 21 having a thickness of about 0.05 m is used, the plate member 21 is fixed to the ground or the foundation 16 with a bolt, A sphere 12 can be inserted into the sphere. In this case, when the plate member 21 having a thickness of about 0.02 m is used, if the ball member 12 is directly fixed to the ground or the base 16, the ball member 12 easily comes out from the hole 20 due to the rotation of the ball member 12. Can be disposed at a position about 0.04 to about 0.06 m away from the ground or foundation 16 to prevent the sphere 12 from exiting from the hole 20 and to be rotatable.

  So far, the seismic isolation device of the present invention has been described in detail with reference to the drawings, but the seismic isolation device of the present invention is not limited to the embodiment shown in the drawings. In the present invention, in addition to these seismic isolation devices, it is also possible to provide a floating roof tank equipped with these seismic isolation devices that can suppress the occurrence of sloshing.

The figure which illustrated the floating roof type tank provided with a seismic isolation apparatus. The top view of the floating roof type tank shown in FIG. The figure which showed the place which is suppressing sloshing using a seismic isolation apparatus. The figure which showed 2nd Embodiment of the seismic isolation apparatus. The figure which showed 3rd Embodiment of the seismic isolation apparatus.

Explanation of symbols

10a ... Bottom plate 10b ... Side plate 11 ... Floating roof 12 ... Spheres 13, 13a, 13b ... Stopper 14, 14a, 14b, 14c, 14d ... Shock absorber 15 ... Seismic isolation device 16 ... Ground or foundation 17 ... Container 18 ... Container 19 ... water 20 ... hole 21 ... plate member 22 ... connector

Claims (8)

A seismic isolation device is used for a container that has a floating roof that floats on and covers the liquid level, and suppresses the occurrence of sloshing,
A plurality of spheres disposed between a bottom plate of the container and a flat ground or foundation, and movably supporting the container;
A stopper extending vertically from the ground or foundation so as to surround the periphery of the container and constructed on the ground or foundation;
On both the outer wall and the stopper of the container, viewed including the so provided are cushioning material so as to face each other, the container has an inner diameter of a cylindrical vessel of L, the outer wall of the container stopper A seismic isolation device characterized in that the distance between and is less than 0.25L .   The seismic isolation device according to claim 1, wherein the stopper forms a housing portion that houses the container, and water is stored in the housing portion in which the container is housed. The seismic isolation device according to claim 2 , wherein the buffer material is a ring-shaped damper, and absorbs vibration energy of the container and suppresses overflow of the water stored in the housing portion. Each of the plurality of spheres includes a plurality of holes that can be inserted and spaced apart from each other, a plate member having an outer diameter smaller than the outer diameter of the container, and a connector for connecting the plate member to the ground or the foundation. further wherein said each of said plurality of spheres each of the plurality of holes are inserted rotatably, seismic isolation device according to any one of claims 1-3. A floating roof tank equipped with a seismic isolation device for suppressing the occurrence of sloshing,
A container for storing liquid;
A floating roof that floats on and covers the liquid level;
A plurality of spheres disposed between a bottom plate of the container and a flat ground or foundation, and movably supporting the container; and extending vertically from the ground or foundation so as to surround the container; or a stopper which is built on a foundation, in both the outer wall and the stopper of the container, seen including a cushioning member provided so as to face each other, the container has an inner diameter in a cylindrical container of L A floating roof tank comprising: a seismic isolation device characterized in that a distance between an outer wall of the container and the stopper is shorter than 0.25L . The floating roof tank according to claim 5 , wherein the stopper forms an accommodating portion for accommodating the container, and water is stored in the accommodating portion in which the container is accommodated. The floating roof tank according to claim 6 , wherein the cushioning material is a ring-shaped damper and absorbs vibration energy of the container and suppresses overflow of the water stored in the housing portion. Each of the plurality of spheres includes a plurality of holes that can be inserted and spaced apart from each other, a plate member having an outer diameter smaller than the outer diameter of the container, and a connector for connecting the plate member to the ground or the foundation. The floating roof tank according to any one of claims 5 to 7 , further comprising: a plurality of the spheres rotatably inserted into the plurality of holes.

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