JP2007246103A - In-tank liquid stabilizing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an in-tank liquid stabilizing device capable of effectively stabilizing the oscillation of liquid stored in a floating roof type tank. <P>SOLUTION: The in-tank liquid stabilizing device 20 comprises an oscillation suppressing plate 22 with one end thereof connected to the lower side 18a of a floating roof 18 of a floating roof type tank storing liquid 14 in an oscillating manner, and an angle holding mechanism 50 for hanging and holding the other end of the oscillation suppressing plate 22 at a predetermined angle with respect to the lower side of the floating roof 18. The angle holding mechanism 50 comprises an expandable rod 24 which is provided at one side of the oscillation suppressing plate 22 with the upper end thereof pivotably attached to the floating roof 18 and the lower end thereof pivotably attached to the oscillation suppressing plate 22, and a supporting rod 30 which is provided on the other end of the oscillation suppressing plate 22 with the lower end thereof pivotably attached to the oscillation suppressing plate 22 and the upper end thereof fixed to the lower side of the oscillation suppressing plate 22, and movable along the lower side of the floating roof 18 when the upper end is unfixed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an apparatus for reducing liquid in a tank that effectively reduces liquid sloshing (sloshing) caused by an earthquake or the like with respect to a floating roof tank that stores liquid outdoors.

  In general, a floating roof tank is known as a large tank for storing a liquid such as crude oil or naphtha outdoors. A floating roof type tank has a lid called a floating roof on the surface of a liquid such as crude oil stored in a cylindrical tank body with no roof and an open top, and a sealant between the floating roof and the tank body To prevent the crude oil from evaporating. The floating roof moves up and down in the tank body as the liquid level changes as the liquid in the tank body increases and decreases. In this floating roof type tank, even if the liquid in the tank is reduced, crude oil, naphtha, etc. do not come into contact with the air, so that it is possible to avoid danger such as fire.

  However, when an earthquake occurs and the tank is shaken, the floating roof is also shaken along with the rocking (sloshing) of the liquid in the tank. In particular, when a vibration having a period of about 1 second to several tens of seconds is applied to the tank, the liquid surface greatly fluctuates in accordance with the natural period of the fluctuation of the liquid in the tank. For this reason, when a large amount of crude oil or the like is stored in the tank, the floating roof tilts greatly due to large fluctuations in the liquid level, and crude oil or the like spills out of the tank, or the floating roof is attached to the tank body. It crashes and breaks, and when it collides, a spark is generated and it becomes a fire.

For this reason, various devices for preventing the oscillation of the liquid have been considered. For example, a plurality of water control plates that are folded up and down via a hinge are arranged to partition the inside of the tank and reduce the hydraulic pressure generated in the tank. There are some (as shown in Patent Document 1 and Patent Document 2).
JP-A-57-142892 JP 2005-297986 A

  However, the conventional vibration reduction device in which the swing suppression plate is suspended from the floating roof is in a state in which the swing suppression plate is pivotably suspended from the floating roof, and thus freely swings and bends. Therefore, when the liquid oscillates, the oscillating suppression plate oscillates and bends following the flow of the liquid, so that an effective anti-swaying effect cannot be obtained.

  Also, when the liquid in the tank body is pulled out and the floating roof descends to the bottom surface of the tank body and the rocking occurs, the rocking suppression plate folded together with the floating roof also rocks and is provided near the bottom surface of the tank body There is a risk of damaging a structure, for example, a drainage device that drains rainwater collected on the floating roof to the outside.

  The present invention has been made to solve the above-described problems of the prior art, and an object thereof is to provide an apparatus for reducing liquid in a tank that can effectively reduce the vibration of stored liquid. It is said. It is another object of the present invention to provide an apparatus for reducing liquid in the tank that does not affect the vertical movement of the floating roof.

  In order to achieve the above object, an apparatus for reducing liquid in a tank according to the present invention is an apparatus for reducing liquid in a tank that suppresses rocking of liquid stored in a floating roof type tank. It is characterized by having a plate-like vibration-reducing member that is swingably attached to the lower surface, and an angle holding mechanism that is provided on the lower surface of the floating roof and retains the vibration-reducing member at a predetermined angle.

  In this case, a plurality of the attenuating members may be provided so as to intersect each other, and each of them is arranged in the diameter direction of the floating roof. Further, the angle holding mechanism may make the rocking member fallable when the floating roof is lowered to the lower limit. Furthermore, it is preferable that the rocking member is composed of a plurality of rocking suppression plates, and the angle holding mechanism is provided corresponding to the rocking suppression plate.

  In addition, the angle holding mechanism is provided on one side of the vibration reducing member, the upper end is pivotally attached to the floating roof, the lower end is pivotally attached to the vibration reducing member, and the other side of the vibration reducing member. A support rod that is provided and has a lower end pivotally attached to the vibration-reducing member, and an upper end that can be fixed to the lower surface of the floating roof, and that can move along the lower surface of the floating roof when the fixing is released; It is good to have. The rocking member has a rolling member or a sliding member at a lower end, and the tank body that stores the liquid rolls or slides the rolling member or the sliding member in contact with the bottom. It is good to have the inclination part which falls the said rocking member.

  The present invention as described above includes an angle holding mechanism that holds the vibration reducing member attached to the lower surface of the floating roof at a predetermined angle, so that the liquid in the tank body is shaken by sloshing. When moved, the vibration reducing member does not oscillate and bend following the flow of the liquid, resists the horizontal flow generated near the liquid surface, and suppresses the flow to effectively reduce the vibration. Can be obtained.

  A plurality of the vibration reducing members are provided so as to cross each other, and each of them is arranged in the diameter direction of the floating roof. For this reason, against the earthquake acceleration acting from either the east, west, south, or north direction when an earthquake occurs, any of the anti-vibration members that cross each other resists the flow of the liquid in the horizontal direction and suppresses the oscillation. An effective rocking effect can be obtained.

  When the liquid in the tank main body is drawn out and the floating roof is lowered to the lower limit, the angle holding mechanism overturns the vibration reducing member. For this reason, the vibration reducing member held at a predetermined angle with respect to the lower surface of the floating roof can fall down horizontally along the lower surface of the floating roof, and the floating roof can be lowered to the vicinity of the bottom surface. Further, there is no possibility that the rocking suppression plate held at a predetermined angle with respect to the lower surface of the floating roof collides with the bottom surface of the tank main body and damages the structure installed near the bottom surface of the tank main body.

  An angle holding mechanism is provided for each of the plurality of rocking suppression plates constituting the rocking member. For this reason, it is possible to divide the vibration reducing member, that is, to arrange a plurality of vibration suppressing plates side by side and hold each of the vibration suppressing plates at a predetermined angle. Further, even if a gap is provided between adjacent swing suppression plates, a predetermined angle can be maintained for each swing suppression plate.

  The angle holding mechanism has a telescopic rod and a support rod, and the support rod can move along the lower surface of the floating roof when the fixation is released. For this reason, the vibration reducing member held at a predetermined angle with respect to the lower surface of the floating roof can fall down horizontally along the lower surface of the floating roof, and the floating roof can be lowered to the vicinity of the bottom surface. Further, the vibration reducing member does not affect the vertical movement of the floating roof.

  The rocking member has a rolling member or a sliding member at the lower end, and the tank body that stores the liquid rolls or slides the rolling member or the sliding member that is in contact with the bottom. It has an inclined part that falls. For this reason, when the floating roof settles on the bottom surface of the tank, the rocking suppression plate falls down smoothly.

  A preferred embodiment of a device for reducing liquid in a tank according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing a schematic configuration of a tank liquid reducing device according to the first embodiment. FIG. 2 is an explanatory view of a vibration reducing device installed in a floating roof type tank. FIG. 6 is an explanatory diagram of a floating roof tank.

  First, in FIG. 6, the floating roof type tank 10 stores a liquid 14 such as crude oil in the tank body 12. A floating roof 18 is floated on the liquid level 16 of the liquid 14. The floating roof type tank 10 is provided with a sealing member (not shown) between the tank body 12 and the floating roof 18 to prevent the liquid 14 stored in the tank body 12 from evaporating. . Further, a vibration reducing device 20 as shown in FIG. 2 is provided on the lower surface of the floating roof 18 in order to reduce the fluctuation of the liquid 14.

  In the embodiment, the vibration reduction device 20 has a pair of plate-shaped vibration reduction members 40 (40a, 40b) arranged orthogonally to each other and arranged in the diameter direction of the tank body 12, and a predetermined angle between the vibration reduction member 40. A plurality of angle holding mechanisms 50, which will be described later in detail, are the main components.

  The vibration reducing member 40 includes a plurality of vibration suppression plates 22 that are swingably attached to the lower surface of the floating roof 18, and the vibration suppression plates 22 are arranged side by side in the horizontal direction. Each rocking member 40 is arranged with a gap f in each rocking suppression plate 22, and when the floating roof 18 rocks and elastically deforms, adjacent rocking suppression plates 22 come into contact with each other. Is prevented, and the deformation of the floating roof 18 can be easily followed. And in the center part of the floating roof 18 where the vibration reducing members 40a and 40b intersect, either one is provided so as not to interfere with each other.

  The rocking | fluctuation suppression board 22 which comprises the rocking | fluctuation member 40 is a board suspended in the perpendicular direction from the lower surface of the floating roof 18, as shown in FIG. As shown in the figure, the upper end portion of the rectangular swing suppression plate 22 is attached to the lower surface of the floating roof 18 via a hinge 28a, and is swingable in the direction indicated by the arrow a in the figure. The rocking suppression plate 22 has a certain degree of rigidity that resists the rocking of the liquid 14 generated in the tank main body 12, and has corrosion resistance that does not corrode by the liquid 14 stored in the tank main body 12. Good. The shape of the rocking suppression plate 22 is rectangular in consideration of ease of accommodation when the liquid level is lowered, and is elliptical, semicircular from the hinged end to the other end on the suspension side, You may form in a polygonal shape. Further, the length of the swing restraining plate 22 suspended from the floating roof 18 is set in consideration of the effect that the wave height is halved by the housing or swinging when the floating roof 18 is lowered. The maximum length of the swing suppression plate 22 is, for example, about ½ of the tank radius or about ½ of the liquid level height stored in the tank at the rated level, and the minimum length is the liquid level stored at the rated level in the tank. It is good to set to about 1/4 of the height.

  The angle holding mechanism 50 includes the telescopic rod 24 and the support rod 30 that hold the vibration reducing member 40 suspended in the vertical direction from the floating roof 18 toward the bottom surface of the tank body 12 at a predetermined angle. The angle holding mechanism 50 is provided corresponding to each swing suppression plate 22.

  The telescopic rod 24 is attached to the one surface 22a side of the swing suppression plate 22 that is swingably attached to the lower surface of the floating roof 18. That is, the telescopic rod 24 is arranged on the right side of the swing suppression plate 22 in FIG. 1. In the embodiment, the upper end is pivotally attached to the lower surface of the floating roof 18 via the hinge 28b, and the lower end is pivoted. It is pivotally attached to the lower end part of this through the hinge which is not illustrated. A stopper 25 is attached to the rod 24 a of the telescopic rod 24. The stopper 25 prevents the rod 24a from contracting so that the lower end of the swing suppression plate 22 does not rotate to the one surface 22a side (right side in FIG. 1) from the vertical direction with respect to the lower surface of the floating roof 18. On the other hand, the telescopic rod 24 is configured to allow the lower end of the rocking suppression plate 22 to rotate toward the other surface 22b due to the extension of the rod 24a.

  The support rod 30 enables the rocking suppression plate 22 to fall along the lower surface of the floating roof 18 together with the telescopic rod 24 when the liquid 14 in the tank body 12 is drawn and the floating roof 18 is lowered. Yes. As shown in FIG. 1, the support rod 30 is attached to the other surface 22 b of the swing suppression plate 22, that is, on the opposite side of the surface 22 a where the telescopic rod 24 is disposed so as to face the telescopic rod 24. The support rod 30 is a rod-shaped member that maintains a constant length and has a certain degree of rigidity and corrosion resistance against the flow of the liquid 14 stored in the tank body 12. A lower end 30a of the support rod 30 is a lower end portion 22c of the rocking suppression plate 22, and is pivotally attached to a position facing the telescopic rod 24 via a hinge (not shown). On the other hand, a pair of rail wheels 31 is attached to the upper end 30b of the support rod 30 via a shaft (not shown).

  The pair of rails (32a, 32b) are provided in parallel to each other, and are perpendicular to the swing suppression plate 22 swingably attached to the lower surface of the floating roof 18, and are provided on the lower surface of the floating roof 18. Arranged along. The pair of rail wheels 31 are respectively arranged on the upper surface of the rail 32 and can roll on the rail 32. A normally closed stopper 34 is provided at the upper end of the rail 32 at the end on the side of the swing suppression plate 22. Normally, the rail wheel 31 moves away from the swing suppression plate 22 (arrow b direction). To prevent rolling.

The stopper 34 according to the embodiment includes, for example, a pair of wedge-shaped members 34a and 34b that are rotatably provided. These members 34a and 34b are normally closed by being biased by a spring 34c or the like, and when the floating roof 18 is lowered to a predetermined position as will be described later, a cylinder (not shown) or the like is used for the spring 34c. It is released against the urging force and enables the rail wheel 31 to roll in the direction of arrow b.
At the lower end of the swing suppression plate 22, rollers and wheels 27 serving as rolling members are installed.

  A slope 35 serving as an inclined portion is provided on the bottom surface 12a of the tank body 12 at a position where the wheel 27 contacts. When the wheel 27 comes into contact with the slope 35, the wheel 27 rolls along the slope, and rotates the lower end of the swing suppression plate 22 provided so as to be swingable in the clockwise direction in FIG. For this reason, the rocking | fluctuation suppression board 22 falls so that the bottom face 12a may be met. In addition, it may replace with rolling members, such as a wheel and a roller, and sliding members, such as a spherical body which can slide down the slope 35, may be sufficient.

  The operation of the tank liquid reducing device 20 according to the embodiment described above is as follows. FIG. 3 is an explanatory view showing the operating state of the vibration reduction device 20. When the liquid 14 is sufficiently stored in the floating roof tank 10 as shown in FIG. 5A, the swing suppression plate 22 attached to the lower surface of the floating roof 18 is swingably reduced. It is held at a predetermined angle (in the case of the embodiment, vertical) by the device 20. That is, the swing suppression plate 22 is fixed by the stopper 34 via the support rod 30 to rotate clockwise in FIG. Further, the swing suppression plate 22 is fixed by rotating the stopper 25 against the tip of the cylindrical body outside the telescopic rod 24 to rotate counterclockwise. Thereby, the rocking | fluctuation suppression board 22 hold | maintains perpendicular | vertical with respect to the floating roof 18. FIG.

  FIG. 4 is a schematic diagram showing the flow velocity distribution of the floating roof tank. When subjected to earthquake acceleration, liquid oscillation in the primary mode (hereinafter referred to as the basic mode) occurs predominantly in both the circumferential and radial directions. In the basic mode, the liquid moves to the left and right. FIG. 4 shows a state in which the liquid 14 in the tank main body 12 moves to the left, and is pressed against the left inner surface of the tank main body 12. For this reason, the pressure of the left side part in the tank main body 12 becomes high, the liquid level 16a rises, the pressure of the right side part becomes low, and the liquid level 16b falls.

  At this time, the flow velocity distribution in the vicinity of the center of the tank body 12 has the largest flow in the horizontal direction X on the liquid surface of the liquid 14 as shown by the curve A1 in the figure, and the flow gradually toward the bottom surface 12a of the tank body 12. It tends to be smaller. Similarly, as indicated by a curve A2, the horizontal direction X flow of the liquid 14 is the largest near the center of the tank body 12.

  On the other hand, in the flow velocity distribution near the side wall of the tank body 12, the flow in the vertical direction Y on the liquid surface of the liquid 14 becomes the largest as shown by the curve B in the figure, and the flow gradually toward the bottom surface 12a of the tank body 12. It tends to be smaller.

  At this time, the liquid 14 is arranged on the upper part in the diameter direction of the floating roof 18, and since the anti-vibration member 40 including the plurality of oscillation suppression plates 22 fixed and held perpendicular to the floating roof 18 is disposed, Oscillation is suppressed. That is, when the liquid 14 swings, the liquid 14 pushes the floating roof 18 through the anti-vibration member 40 and gives a rotational moment, thereby generating a large resistance to flow. As a result, the vibration reducing member 40 can suppress the flow in the horizontal direction X generated near the liquid surface of the liquid 14 in the tank body 12 and can obtain a large vibration reducing effect. Moreover, since the vibration reducing member 40 is arranged in the diametrical direction passing through the center of the floating roof 18, it resists the flow at the place where the horizontal flow velocity of the liquid 14 is the largest, and the floating roof 18 swings, that is, The effect of suppressing the oscillation of the liquid 14 can be increased. The same applies when the earthquake acceleration acts in the reverse direction (left direction in the figure). Further, since the pair of vibration reducing members 40 are arranged orthogonally through the center of the lower surface of the floating roof 18, even if the earthquake acceleration acts in any direction of east, west, south, and north, the liquid 14 is effectively swung. Can be suppressed.

  Next, the case where the liquid 14 stored in the tank body 12 is drawn out and the floating roof 18 is lowered will be described. Until the wheel 27 provided at the lower end of the swing restraint plate 22 contacts the bottom surface 12a of the tank body 12, the swing restraint plate 22 is angled in advance by the telescopic rod 24 and the support rod 30 (in the case of the embodiment, the floating roof 18). The angle is orthogonal to the angle). As shown in FIG. 3 (B), when the liquid level 16 is lowered, the floating roof 18 is lowered, and the wheel 27 provided at the lower end of the swing suppression plate 22 approaches the slope 35 provided on the bottom surface 12a, A cylinder (not shown) is operated to open the stopper 34 attached to the rail 32. As a result, when the floating roof 18 further descends as the liquid 14 is drawn, the wheel 27 comes into contact with the slope 35 attached to the bottom surface 12a and rolls along the slope of the slope 35 leftward in FIG. For this reason, as shown in FIG. 3 (B), the swing suppression plate 22 rotates in the clockwise direction with the lower end at the hinge 28a. As the wheel 27 rolls, the rail wheel 31 attached to the upper end 30b of the support rod 30 passes through the stopper 34 and rolls on the rail 32 in the direction of arrow c. Further, the rod 24a of the telescopic rod 24 is pulled out and extended with the clockwise rotation of the lower end of the swing suppression plate 22. After the rail wheel 31 passes through the stopper 34 on the rail 32, for example, when the floating roof comes to a predetermined height position, the cylinder may be operated to return the stopper 34 to the closed state.

  When the liquid 14 is completely extracted from the tank body 12, the floating roof 18 descends to the lower limit, and the swing suppression plate 22 falls along the bottom surface 12a as shown in FIG. Accordingly, the floating roof 18 can be lowered to the vicinity of the bottom surface 12a without affecting the vertical movement of the floating roof 18.

  Further, when the liquid 14 is injected into the tank body 12 from a state where the rocking suppression plate 22 has fallen horizontally along the lower surface of the floating roof 18, one end (upper end portion) of the rocking suppression plate 22 as the floating roof 18 rises. Is raised. Further, as the floating roof 18 rises, the wheel 27 attached to the lower end of the swing suppression plate 22 rolls up the slope 35. As a result, the other end (upper end) of the support rod 30 is pulled out to the swing suppression plate 22 side, and the rail wheel 31 attached to the other end of the support rod 30 moves on the rail 32 in the direction of the arrow d in FIG. Roll to. For this reason, the telescopic rod 24 is contracted by the rod 24a being pushed into the cylindrical body. When the wheel 27 at the lower end of the swing suppression plate 22 is separated from the bottom surface 12a, the rail wheel 31 passes through the stopper 34 of the rail 32 and the rail wheel 31 is fixed by the stopper 34, and the telescopic rod 24 is stopped. The tool 25 abuts on the end surface of the cylindrical body, and the swing suppression plate 22 is suspended and held in a direction perpendicular to the lower surface of the floating roof 18.

  FIG. 5 is a diagram simulating the liquid level displacement of the vibration reducing device according to the embodiment. The floating roof type tank body according to the embodiment has a diameter of 42 meters, a liquid level height of 19.2 meters, and a vertical length hd of the swing suppression plate is 4.3 meters. The input seismic motion is the seismic acceleration of the EW (east-west) component observed in Tomakomai among seismic motions generated in Hokkaido at around 4:50 am on September 26, 2003. This seismic motion is one of a series of earthquakes named by the Japan Meteorological Agency as the “2003 Tokachi-oki Earthquake”, and a tank fire occurred in the Tomakomai refinery due to this series of earthquakes.

  In the figure, the horizontal axis indicates the time (seconds) from the start of tank vibration, and the vertical axis indicates the liquid level difference (meters) with respect to the reference liquid level (0 meters) where no oscillation occurs. The solid line (with plate) indicates the liquid level displacement when the vibration reducing device is attached to the floating roof, and the broken line (w / o plates) indicates the liquid level displacement when the vibration reducing device is not attached to the floating roof.

  When the anti-vibration device is attached to the floating roof as shown in the figure, the maximum liquid level difference with respect to the reference liquid level is ± 1.5 meters, whereas when it is not attached, the maximum liquid level difference is about ± 3 meters. It can be seen that the liquid level difference is halved. In addition, as for the time until vibration reduction, when the vibration reduction device is attached, the vibration level is reduced in about 150 seconds from the occurrence of vibration. It is 1 meter and shows the effect that the time to shake is greatly shortened.

  FIG. 7 is a diagram showing a schematic configuration of a tank liquid reducing device according to the second embodiment. In addition, about the component same as 1st Embodiment, the same effect is comprised and the description is abbreviate | omitted.

  The configuration of the second embodiment, which is different from the first embodiment, is that the angle holding mechanism 50a has the telescopic rod 24A and the stopper 25A as main components. FIG. 8 is an explanatory view of an angle holding mechanism according to the second embodiment. The telescopic rod 24A according to the second embodiment has an upper end pivotally attached to the lower surface of the floating roof via a hinge and a lower end pivotally attached to the lower end of the swing suppression plate 22 via a hinge (not shown). The swing suppression plate 22 is suspended and held from the one surface 22a side of the motion suppression plate 22. At this time, the stopper 25A attached to the rod 24a contacts the end surface of the cylindrical body 24b to prevent the rod 24a from being reduced. On the other hand, the fixing means 60 attached to the cylindrical body 24b prevents the rod 24a from extending (moving in the direction of arrow e in the figure). As shown in FIG. 8, the fixing means 60 is attached to the lower end of the telescopic rod 24 </ b> A, and includes a protrusion 62, a wedge 64, and a spring 66 as main components. The protrusion 62 is a substantially H-shaped member that fits into an opening provided at the lower end of the cylindrical body 24b. The wedge 64 has one end rotatably attached to the lower end of the rod 24 a, and the other end is in contact with the side wall of the opening by the extension of the spring 66. Further, a rod member 68 that comes into contact with the protruding portion 62 is attached to the tank bottom surface 12 a below the protruding portion 62.

  With this configuration, when the liquid 14 is sufficiently stored in the floating roof tank 10, the swing suppression plate 22 that is swingably attached to the lower surface of the floating roof 18 rotates counterclockwise in FIG. 8. Is fixed by a stopper 25A attached to the support rod 24a. That is, the stopper 25A attached to the rod 24a contacts the lower end of the cylindrical body 24b to prevent the rod 24a from being reduced. Further, the swinging suppression plate 22 is fixed by the fixing means 60 so as to rotate clockwise. That is, in the fixing means 60, the lower end of the wedge 64 comes into contact with the side wall of the opening due to the extension of the spring 66, thereby preventing the rod 24a from extending.

  As a result, the swing of the swing restraining plate 22 can be held at a predetermined angle, and in the same way as in the first embodiment, the swing restraining plate 22 resists the horizontal flow generated near the liquid surface of the tank body 12 and swings. Motion can be effectively suppressed.

  Next, when the liquid 14 stored in the tank body 12 is pulled out and the floating roof 18 is lowered, the protrusion 62 comes into contact with the rod member 68 attached to the bottom surface 12 a of the tank body 12. Then, the protrusion 62 is pushed toward the center of the cylindrical body 24b, the wedge 64 is pushed back in the direction of the arrow f against the extension pressure of the spring 66, the lower end of the wedge 64 is separated from the side wall of the opening, and the rod 24a The lock is released. And the wheel 27 provided at the lower end of the rocking | fluctuation suppression board 22 contacts the slope 35 provided in the bottom face 12a of the tank main body 12, and it rolls to the left direction of FIG.

  As a result, when the liquid 14 is completely extracted from the tank body 12, the swing suppression plate 22 falls in the horizontal direction along the lower surface of the floating roof 18.

  In addition, when the liquid 14 is injected into the tank body 12 from a state where the rocking suppression plate 22 has fallen horizontally along the lower surface of the floating roof 18, the upper end portion of the rocking suppression plate 22 is pulled up as the floating roof rises. The upper end of the telescopic rod 24A is raised. In addition, the rod 24a of the telescopic rod 24 is pushed into the cylindrical body 24b by the pulling up of the upper end portion of the swing suppression plate 22 to be reduced. When the wheel 27 at the lower end of the swing suppression plate 22 is separated from the bottom surface 12a, the stopper 25A of the telescopic rod 24A comes into contact with the end surface of the cylindrical body 24b. The wedge 64 is inserted into the cylindrical body 24b and pushed out to the opening side by the extension of the spring 66. The lower end of the wedge 64 abuts against the side wall of the opening, the expansion and contraction of the rod 24a is restricted, and the swing suppression plate 22 is lifted. It is suspended and held in a direction perpendicular to the lower surface of 18.

  In such a vibration reducing device, when the liquid is sufficiently stored in the tank body, the rocking suppression plate is suspended and held at a predetermined angle with respect to the lower surface of the floating roof. The horizontal flow is resisted, the oscillation is suppressed, and a great vibration reduction effect can be obtained. Further, when the liquid in the tank body is drawn out and the floating roof descends, the rocking suppression plate falls down along the lower surface of the floating roof, so there is no possibility that the rocking suppression plate hits the bottom surface of the tank main body and is damaged.

  In this embodiment, the swing suppression plate is suspended and held in the vertical direction with respect to the lower surface of the floating roof, but in addition to this, the suspension angle is set to a predetermined angle, for example, from the vertical direction to the support rod side, That is, the swing suppression plate may be suspended and held at an angle of 1 to 5 degrees slightly tilted toward the falling side. Thereby, when the rocking | fluctuation suppression board contact | connects the bottom face of a tank main body, a wheel can be rolled to the left direction of FIG.1, FIG.3, FIG.7 along a bottom face, without attaching a slope beforehand.

  In addition, the telescopic rod and the support rod for suspending and holding the rocking suppression plate according to the embodiment have been described with the configuration connected to the lower end portion of the rocking suppression plate. It is good also as a structure connected on the spaced apart arbitrary side surfaces. A cylinder may be used for the telescopic rod and the support rod according to the embodiment. The fixing means of the second embodiment is an example, and other means may be used as long as it has an action capable of limiting the expansion and contraction of the rod.

  Further, in order to suspend and hold the swing restraint plate in the vertical direction, the stopper is used in the first embodiment and the fixing means is used in the second embodiment. However, in addition to this, a telescopic damper is used. Also good. Telescopic dampers generally do not resist slow and slow movements, but have the property of increasing resistance as speed increases. When the liquid is poured into and withdrawn from the tank, the up and down movement of the liquid level and the floating roof is a very slow movement, so that the damper does not hinder this movement. On the other hand, the rapid movement that occurs around the vibration suppression plate during an earthquake speeds up the movement of the liquid and makes the damper a resistor. For this reason, the rocking | fluctuation suppression board can maintain the attitude | position of a perpendicular direction with respect to a floating roof. Specifically, in the first embodiment, a telescopic damper can be installed on the rail or an extension line thereof, and one end can be fixed to the upper end of the support rod and the other end can be fixed to the floating roof. In the second embodiment, a telescopic damper can be used instead of the telescopic rod.

It is a figure which shows the structure outline of the anti-tank apparatus of the liquid in a tank which concerns on 1st Embodiment. It is explanatory drawing of the vibration reduction apparatus installed in a floating roof type tank. It is explanatory drawing which shows the operating state of a vibration reduction apparatus. It is a schematic diagram which shows the flow-velocity distribution of a floating roof type tank. It is the figure which simulated the liquid level displacement of the vibration reduction apparatus which concerns on embodiment. It is explanatory drawing of a floating roof type tank. It is a figure which shows the structure outline of the anti-tank apparatus of the liquid in a tank which concerns on 2nd Embodiment. It is explanatory drawing of the angle holding mechanism which concerns on 2nd Embodiment.

Explanation of symbols

10 ......... Floating roof type tank, 12 ......... Tank body, 14 ......... Liquid, 16 ......... Liquid level, 18 ......... Floating roof, 20 ......... Attenuator, 22 ......... Oscillation Inhibiting plate, 24 ......... Extensible rod, 25 ......... Stopper, 27 ......... Wheel, 28 ......... Hinge, 30 ......... Support rod, 31 ......... Rail wheel, 32 ......... Rail, 34... Stopper, 35... Slope, 40.

Claims (6)

A device for reducing liquid in a tank that suppresses rocking of liquid stored in a floating roof type tank,
A plate-like anti-vibration member attached to the lower surface of the floating roof in a swingable manner
An angle holding mechanism that is provided on the lower surface of the floating roof and holds the vibration reducing member at a predetermined angle;
A device for reducing liquid in a tank, comprising:   2. The apparatus for reducing liquid in a tank according to claim 1, wherein a plurality of the attenuating members are provided so as to intersect each other and are arranged in a diameter direction of the floating roof.   The said angle holding | maintenance mechanism makes the said rocking member fall over when the said floating roof descend | falls to a minimum, The liquid rocking device of the tank liquid of Claim 1 or 2 characterized by the above-mentioned. The vibration reducing member is composed of a plurality of vibration suppressing plates,
4. The apparatus for reducing liquid in a tank according to claim 1, wherein the angle holding mechanism is provided corresponding to each of the swing suppression plates. 5. The angle holding mechanism is provided on one side of the vibration reducing member, an upper end is pivotally attached to the floating roof, and a telescopic rod having a lower end pivotally attached to the vibration reducing member,
Provided on the other side of the anti-vibration member, the lower end is pivotally attached to the anti-vibration member, and the upper end can be fixed to the lower surface of the floating roof. Movable support rod,
5. The apparatus for reducing liquid in a tank according to claim 1, further comprising: The rocking member has a rolling member or a sliding member at the lower end,
The tank main body for storing the liquid has an inclined portion that rolls or slides the rolling member or the sliding member that is in contact with the bottom portion to cause the vibration reducing member to fall. The apparatus for reducing liquid in a tank according to any one of claims 1 to 5.

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