JP2007253969A - Sloshing restraining member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain sloshing during an earthquake and to prevent a floating roof from being damaged. <P>SOLUTION: A sloshing restraining member has an undulated resistance plate 12 formed from ridges 12a and furrows 12b that are alternately successive. The member is attached to the underside of a floating roof adjacent to a liquid surface so that the ridges 12a and the furrows 12b are oriented in the direction of the inside face of the tank. The undulated resistance plate 12 has a plurality of first flat plates 13a and a plurality of second flat plates 13b forming a plurality of the ridges 12a and the furrows 13b, which alternate. The first and second flat plates 13a and 13b may have openings 14. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sloshing suppressing material attached to a floating roof in order to suppress sloshing in a container having a floating roof.

  As a tank for storing liquids such as water, petroleum, heavy oil, gasoline, and chemicals, a fixed roof tank, a floating roof tank, and the like are used. Of these liquids, floating roof tanks are often used as tanks for storing volatile liquids such as petroleum, heavy oil, and gasoline. This is because the liquid surface is covered with the floating roof used by floating on the liquid surface, so that the liquid does not volatilize and the liquid loss can be suppressed.

  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 inside is made substantially uniform, and the tank is not easily 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 sealing material around the pontoon and filling the gap with the sealing material, volatilization of the liquid can be suppressed. Since the floating roof is used floating on the liquid level, it rises as the liquid level rises due to the supply of liquid, and falls as the liquid level drops due to the liquid removal.

  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 resonance occurs because the period due to earthquake motion and the natural period of the tank coincide, a phenomenon called sloshing where the liquid level greatly swells due to this resonance occurs.

  This sloshing continues even when the earthquake stops, causing not only rocking motion but also rotational motion on the floating roof, 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. The sloshing vibration continues for a long time because the attenuation rate of the contents is small. This is because if the tank contents are flammable liquid such as petroleum, the flammable liquid will continue to overflow, and the presence of an ignition source may cause a major fire. For this reason, the floating roof type tank is provided with a device for suppressing the movement of the floating roof due to sloshing by giving resistance to the movement of liquid inside the tank during an earthquake or fixing the floating roof. ing.

  For example, a resistance plate that floats due to the flow of the tank contents, and a support that is movably installed on the bottom surface of the tank while sinking in the tank contents and supports the resistance plate that floats by buoyancy in the tank contents An apparatus having a wire connecting the resistance plate and the support has been proposed (see Patent Document 1). This device suppresses the liquid level from greatly undulating by providing resistance to the flow of the tank contents by the resistance plate.

  In addition, a resistance plate formed by hanging a linear body on the lower surface of the floating roof and connecting a pair of plate-shaped bodies in a tiltable manner is inclined only in a direction in which each plate-shaped body is closed upward from a state where each plate-shaped body is developed substantially horizontally In order to be able to do so, what is suspended and supported by a linear body has been proposed (see Patent Document 2). When the floating roof swings upward, each plate-like body of the resistance plate develops substantially horizontally and receives resistance from the liquid, thereby suppressing the swing of the floating roof.

The resistance plate gives resistance to the flow of the tank contents in the tank contents, and the flow near the liquid level cannot be directly attenuated. For this reason, even if the liquid level is not large, it undulates. In addition, these resistance plates cause the tank contents to collide with the flow in the horizontal direction that occurs parallel to the ground or the bottom surface of the tank, and then to the flow in the vertical direction that collides with the tank side wall. To give resistance. For this reason, when the flow is accelerated before colliding with the resistance plate, there is a problem that the resistance plate receives a strong force and is damaged. Moreover, since this force is applied not only to the resistance plate but also to the floating roof, there is a problem that the floating roof is damaged. Even if it does not lead to breakage, there is a problem that sloshing is generated in order to increase the ripple of the liquid level.
Japanese Patent Laying-Open No. 2005-280738 JP-A-9-142575

  The present invention has been made in order to solve the above-described problems, and provides a sloshing suppression material that can attenuate sloshing by attenuating both the liquid flow near the liquid surface and the liquid flow inside the container. For the purpose.

  As a result of intensive studies, the inventors attached a corrugated resistance plate to the lower surface of the deck plate covering the central portion of the floating roof so that the crests and troughs face the inner surface of the container, and the liquid flowing near the liquid surface It was found that the flow of the liquid near the liquid surface can be attenuated by imparting resistance to the liquid and branching the flow in multiple directions, thereby suppressing sloshing. The said subject is achieved by providing the sloshing suppression material of this invention.

  That is, the sloshing suppression material of the present invention is composed of a corrugated resistance plate in which peaks and valleys are alternately continued, and the peaks and valleys are containers on the lower surface of the central portion of the floating roof adjacent to the liquid surface. It is attached so that it may face the inner surface.

  This sloshing suppression material may be comprised from the several waveform resistance board, and can be attached to the lower surface of a floating roof so that it may arrange in parallel and to extend radially.

  The corrugated resistor plate includes a plurality of first flat plate portions and a plurality of second flat plate portions forming a plurality of peaks and valleys, and the first flat plate portions and the second flat plate portions are alternately arranged. In addition, an opening may be provided in one or both of the first flat plate portion and the second flat plate portion.

  In addition, the opening is composed of a perforated plate having a plurality of small holes, a mesh having a mesh, or a plurality of small plates arranged so as to partially overlap each other, and opens and closes according to the flow direction of the liquid. Any of the blind members can be attached.

  By providing the sloshing suppressing material of the present invention, it is possible to attenuate the flow of liquid near the liquid surface and suppress sloshing. Since sloshing is suppressed in this way, the swinging of the floating roof can be suppressed and the floating roof is not damaged.

  The sloshing suppression material of this invention is demonstrated in detail with reference to drawings. Examples of the container provided with a floating roof that floats on the liquid surface and covers the liquid surface include floating roof tanks used for storing petroleum, heavy oil, gasoline, and the like. FIG. 1 is a view showing a state where a sloshing suppressing material is attached to a floating roof of a floating roof type tank. The floating roof tank is a deck composed of a circular bottom plate 10a made of steel and a side plate 10b that is continuous with the bottom plate 10a and formed in a cylindrical shape, and a steel plate that covers the center of the liquid surface. It is comprised from the floating roof 11 comprised from the board 11a and the pontoon 11b connected to the circumference | surroundings of the deck board 11a. Although not shown in FIG. 1, the side plate 10b is provided with a supply nozzle for supplying liquid into the tank and a discharge nozzle for discharging the liquid inside the tank. A sealing material is provided to fill the gap between 11b and the side plate 10b.

  The pontoon 11b is hollow so that the floating roof 11 floats on the liquid surface, and is mainly manufactured from a steel material or a plastic material such as polyvinyl chloride or fiber reinforced plastic (FRP). As described above, the side plate 10b is formed in a cylindrical shape so that the pressure received from the liquid stored therein is evenly applied. For this reason, the floating roof 11 has a circular deck plate 11a and a circular deck plate 11a around which a plurality of pontoons or ring-shaped pontoons 11b are provided to form a circular shape as a whole. The liquid stored inside can be water, liquid chemicals, etc. in addition to combustible liquids such as petroleum, heavy oil and gasoline.

  Flammable liquids cause a fire due to the presence of ignition sources and pollute the atmosphere. When liquid chemicals flow out of the tank and penetrate into the soil or river, depending on the substance, the soil or river is contaminated. These liquids will not escape from the tank at normal times without earthquakes unless the tank is damaged. However, when an earthquake occurs, sloshing with the liquid surface being greatly swollen occurs, and the floating roof may be lifted, and these liquids may flow out. For this reason, the sloshing suppression material of the present invention is attached to the floating roof in order to prevent sloshing and prevent the floating roof from lifting even during an earthquake.

  The sloshing suppression material is composed of a corrugated resistor plate 12 in which peaks 12a and valleys 12b are alternately continuous. The sloshing suppression material is attached to the lower surface of the central portion of the floating roof 11, specifically, the lower surface adjacent to the liquid surface of the deck plate 11a so that the peak portion 12a of the corrugated resistance plate 12 faces the inner surface of the tank.

  The sloshing suppression material provides resistance to the horizontal flow near the liquid surface and branches the flow in multiple directions. Therefore, although extending from the bottom surface of the deck plate 11a toward the inner bottom surface of the tank, the length thereof is shortened. This length can be set arbitrarily, but depending on the specifications of the tank, that is, the inner diameter, height, etc. of the tank, any prediction formula known so far, scale model experiments will be carried out to determine the sloshing height, The height can be determined in consideration of the height. Depending on the inner diameter and height of the tank, when the inner diameter is about 20 m to about 80 m and the height is about 10 m to about 40 m, for example, the length can be about 2 m to about 10 m.

  This sloshing suppression material can be produced by alternately bending metal plates such as aluminum plates and steel plates in opposite directions and forming them into a corrugated shape. Moreover, it can also shape | mold by using the metal mold | die by which the surface was shape | molded by the waveform, and pressing the said metal plate against the metal mold | die. The angle bent to form the peak 12a and the valley 12b can be about 30 ° to about 120 °. Depending on the liquid to be stored, this metal plate can be plated to provide oil resistance if it is petroleum or the like, and to provide corrosion resistance if it is a chemical. Further, the metal plate has a strength and a thickness that does not bend or cut by the flow of the liquid. The sloshing suppression material can be attached to the lower surface of the deck plate 11a by welding or using fastening means such as bolts and nuts.

  Here, the attenuation of the liquid flow by the sloshing suppression material will be described below. When an earthquake occurs, seismic waves spread concentrically around the epicenter. At the place where the floating roof tank is installed, the ground is swung due to the transverse wave caused by the seismic wave, and the swing is propagated to the floating roof tank. As the floating roof tank swings, the swing propagates to the liquid inside. The liquid receives a force in the swinging direction of the tank and starts to flow in that direction. When the sloshing suppression material is not attached, the liquid flows only in the rocking direction, and is gradually amplified to generate sloshing. However, in this invention, since the sloshing suppression material is attached to the floating roof 11, it collides with this sloshing suppression material and the flow of the liquid is attenuated.

  Since the sloshing suppression material is composed of the corrugated resistance plate 12, the collided liquid branches in a direction different from the swinging direction. For example, when it collides with the front surface of the corrugated resistor plate 12, it branches in at least two directions by the peak portion 12a. There are a plurality of crests 12a, and the liquid collides with the corrugated resistance plate, and the liquids after branching collide with each other and flow in multiple directions. The corrugated resistor plate 12 is attached only to the lower surface of the deck plate 11a. However, the liquid flowing in the swinging direction collides with the liquid flowing in the multi-directional direction to give resistance, and the corrugated resistor plate 12 exists. The flow of liquid below the pontoon 11b that is not damped is also damped.

  The liquid on the inner bottom surface side of the tank starts to flow as the tank swings, but is not attenuated because there is no corrugated resistance plate 12 to collide with. The liquid on the inner bottom surface side of the tank collides with the inner surface of the tank and causes a flow in the liquid surface direction. However, the liquid flowing in the liquid surface direction collides with the liquid flowing in the multi-directional direction and is given resistance, the flow direction is changed, and the force that raises the liquid surface is attenuated.

  The sloshing suppression material of the present invention not only provides resistance to the flow of liquid near the liquid surface, but also functions as a weight for preventing the floating roof 11 from lifting. This increases the total mass of the floating roof 11 and can more effectively suppress sloshing.

  In normal operation, the floating roof 11 moves up and down according to the liquid level. When the liquid level is low, the sloshing suppression material reaches the inner bottom surface of the tank, and the floating roof 11 does not descend below that level. However, since this sloshing suppression material does not have a component for storing or absorbing a liquid, a liquid loss may occur, but all of the liquid can be recovered.

  Further, when the liquid is supplied and stored again after all the liquid is recovered from the tank, a space filled with air is formed between the inner bottom surface of the tank and the floating roof 11, and the liquid is supplied as it is. The liquid is filled and stored in the state having the space. In this case, the liquid volatilizes in the space, resulting in liquid loss. Therefore, in order to eliminate this space, an air valve for extracting air from the deck plate 11a can be provided.

  2 and 3 illustrate an embodiment of the sloshing suppression material. 2 and 3 are views showing the floating roof viewed from the inner bottom surface side of the tank. In the embodiment shown in FIG. 2, a ring-shaped pontoon 11b is provided around a circular deck plate 11a, and a plurality of corrugated resistor plates 12 are attached so as to be arranged in parallel to the lower surface of the deck plate 11a. Yes. Each length in the direction in which the peak portion 12a and the valley portion 12b of the corrugated resistance plate 12 are continuous is set to a length corresponding to the attachment position to the circular deck plate 11a. That is, the length of the corrugated resistor plate 12 attached so as to pass through the center of the circular deck plate 11a is substantially the same as the diameter of the deck plate 11a, and is separated from the corrugated resistor plate 12 attached so as to pass through the center thereof. As it is shortened.

  In the embodiment shown in FIG. 3, a plurality of corrugated resistor plates 12 are attached to the bottom surface of the deck plate 11a so as to be arranged radially. In FIG. 3, a cylindrical member 12c having a diameter smaller than the diameter of the deck plate 11a (arbitrary diameter) is attached to the center portion of the deck plate 11a, and directed from the cylindrical member 12c toward the edge of the deck plate 11a. A plurality of corrugated resistor plates 12 are attached so as to extend radially. In FIG. 3, eight corrugated resistor plates 12 are attached, and the central angle formed by two adjacent corrugated resistor plates 12 is approximately 45 °.

  By attaching a plurality of corrugated resistor plates 12 in this way, it is possible to increase the amount of liquid that collides with the corrugated resistor plate 12 and is given resistance and attenuates. That is, the flow of the liquid near the liquid surface can be more effectively attenuated. Also, as shown in FIG. 3, by arranging the crests 12a of the corrugated resistor plate 12 so as to face different directions, the flow of the liquid can be branched in multiple directions, and the sloshing can be more effectively suppressed. can do.

  FIG. 4 illustrates an embodiment of the corrugated resistor plate 12. FIG. 4A is an enlarged view of the corrugated resistor plate shown in FIG. 1, and FIG. 4B is a diagram showing the corrugated resistor plate having an opening. The corrugated resistance plate 12 shown in FIG. 4A can be produced by forming a metal plate as described above. The corrugated resistance plate 12 thus produced includes a plurality of first flat plate portions 13a and a plurality of second flat plate portions 13b forming a plurality of peak portions 12a and valley portions 12b, and the first flat plate portion 13a The second flat plate portions 13b are alternately arranged. The bending angle is an angle formed by the first flat plate portion 13a and the second flat plate portion 13b. For example, the plurality of first flat plate portions 13a can be arranged in parallel with each other, and the plurality of second flat plate portions 13b can also be arranged in parallel with each other.

  The corrugated resistor plate 12 shown in FIG. 4B can be manufactured by forming the opening 14 by punching a predetermined portion of a metal plate into a rectangle or the like and then forming it as described above. In the embodiment shown in FIG. 4B, an opening 14 is provided at the center of the first flat plate portion 13a and the second flat plate portion 13b. The opening 14 can pass the flowing liquid, and can resist the liquid and attenuate the flow when passing. The corrugated resistor plate 12 not provided with the opening 14 shown in FIG. 4A only collides the flowing liquid, but the corrugated resistor plate 12 provided with the opening 14 shown in FIG. 4B. Can cause the flowing liquid to collide and pass through a part of the liquid to more effectively attenuate the flow of the liquid.

  For example, in addition to a part of the liquid flowing in the swing direction, a part of the liquid colliding with the adjacent second flat plate part 13b also passes through the opening 14 provided in the first flat plate part 13a. Since the opening area of the opening 14 is limited, resistance is given to the liquid passing therethrough. Moreover, each liquid collides and attenuates, and the flow direction changes. The liquid that has passed through collides with the liquid on the inner bottom surface of the tank described above, collides with the inner surface of the tank, changes the flow direction, collides with the liquid flowing in the liquid surface direction, and flows the liquid flowing in the liquid surface direction. Attenuate. By providing the opening 14 as described above, sloshing can be effectively suppressed as compared with the case where the opening 14 is not provided. In FIG. 4B, the opening portion 14 is provided in all of the first flat plate portion 13a and the second flat plate portion 13b, but is provided in one of the first flat plate portion 13a and the second flat plate portion 13b. May be. Moreover, you may provide only in a part of several 1st flat plate part 13a, or only a part of several 2nd flat plate part 13b.

  When the amount of liquid flowing in the swing direction is large, the flow direction cannot be changed, and the resistance given is not sufficient. Therefore, the liquid flows in the liquid surface direction on the inner bottom surface side of the tank. May be generated and the ripples may be amplified. For this reason, a resistance member can be attached to the opening 14 in order to sufficiently provide resistance to the liquid passing therethrough. These resistance members limit the amount of liquid passing through and provide resistance. 5A to 5D illustrate resistance members that can be attached to the opening 14. These resistance members can be attached to the opening portion 14 by welding, bonding, fastening means such as bolts and nuts, and fastening means such as strings. These resistance members are made of a material having rigidity so as not to be damaged by the flow of liquid.

  FIG. 5A shows a perforated plate 51 provided with a plurality of small holes 50. The size of the perforated plate 51 is approximately the same as the size of the opening 14. The porous plate 51 can be made of the same material as the corrugated resistor plate 12. The small holes 50 may have any shape such as a circle, an ellipse, and a rectangle, and may have any number. Examples of the porous plate 51 include a punching plate and an expanded metal.

  FIG. 5B shows a reticulated object 52 having a mesh cut to approximately the same size as the opening 14. The net-like object 52 is formed by knitting a thread, a wire or the like to form a hook-shaped mesh (mesh). The mesh size that is the size of the mesh may be any size. 5 (c) and 5 (d) are blind members 54 and 56 that are composed of a plurality of small plates 53 and 55 that are arranged so as to partially overlap each other, and are opened and closed according to the flow direction of the liquid. The blind member 54 shown in FIG. 5C is composed of a plurality of small plates 53 that are substantially the same length as the longitudinal direction of the opening 14 and shorter than the lateral length of the opening 14. The blind member 56 shown in FIG. 5 (d) is composed of a plurality of small plates 55 that are shorter than the length in the vertical direction of the opening 14 and are substantially the same as the length in the horizontal direction. The small plates 53 and 55 can be made of the same material as the corrugated resistor plate 12.

  The blind members 54 and 56 are arranged so that the small plates 53 and 55 partially overlap each other, and the small plates 53 and 55 have protrusions 53a, 53b, and 55a for rotatably supporting both ends in the longitudinal direction. , 55b. Correspondingly, the opening 14 is provided with grooves for fitting the projections 53a, 53b, 55a, 55b. For this reason, for example, the small plate 53 is rotated by the collision of the liquid with the edge in the lateral direction, and can open the opening 14 and allow the liquid to pass therethrough. In this case, the liquid is given resistance during collision, rotation and passage of the platelet 53, and its flow is sufficiently damped. In the present invention, the plurality of small plates 53 may be fixed so as not to rotate. Even in this case, the liquid flow can be sufficiently attenuated.

  So far, the sloshing suppression material of the present invention has been described in detail with reference to the drawings. However, the sloshing suppression material of the present invention is not limited to the embodiment shown in the drawings. In the drawing, the peak portion is sharp, but it may be rounded off or may be substantially trapezoidal as long as a taper is formed. By providing the sloshing suppressing material of the present invention, it is possible to provide a floating roof to which the sloshing suppressing material is attached and a floating roof type tank equipped with the floating roof.

The figure which showed the place which attached the sloshing suppression material to the floating roof of the floating roof type tank. The figure which showed 1st Embodiment of the sloshing suppression material. The figure which showed 2nd Embodiment of the sloshing suppression material. The figure which illustrated the corrugated resistance board used for a sloshing suppression material. The figure which illustrated the resistance member attached to the opening part provided in the waveform resistance board.

Explanation of symbols

10a ... Bottom plate 10b ... Side plate 11 ... Floating roof 11a ... Deck plate 11b ... Pontoon 12 ... Corrugated resistance plate 12a ... Mountain portion 12b ... Valley portion 12c ... Cylindrical member 13a ... First flat plate portion 13b ... Second flat plate portion 14 ... Opening 50 ... small hole 51 ... perforated plate 52 ... net-like material 53, 55 ... small plate 53a, 53b, 55a, 55b ... projection 54, 56 ... blind member

Claims (5)

In a container provided with a floating roof that floats on the liquid surface and covers the liquid surface, a sloshing suppression material that is attached to the floating roof to suppress sloshing,
It consists of a corrugated resistor plate in which crests and troughs are alternately continuous, and the crests and troughs face the inner surface of the container on the lower surface of the central part of the floating roof adjacent to the liquid surface Sloshing suppression material characterized by being attached as follows.   The sloshing suppression material according to claim 1 which consists of a plurality of said wave resistance plates attached so that it may be arranged in parallel.   The sloshing suppression material according to claim 1, comprising the plurality of corrugated resistance plates attached so as to extend radially.   The corrugated resistor plate includes a plurality of first flat plate portions and a plurality of second flat plate portions forming a plurality of the crests and valleys, and the first flat plate portions and the second flat plate portions are alternately arranged. The opening part is provided in either one or both of the said 1st flat plate part and the said 2nd flat plate part, The any one of Claims 1-3 characterized by the above-mentioned. Sloshing suppression material. The opening comprises a perforated plate in which a plurality of small holes are formed, a mesh having a mesh, or a plurality of small plates arranged so as to partially overlap each other, and is opened and closed according to the flow direction of the liquid. Any of the blind members is attached, The sloshing suppression material of Claim 4 characterized by the above-mentioned.

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