JP2008167801A - Dome structure, storage tank and method of extinguishing fire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid inconvenience caused by the environment for setting a storage tank and the weather by a dome part covering a floating roof, to prevent a fire occurring on the floating roof by a ventilation shutting means, and to swiftly and smoothly extinguish the fire by means of the smothering fire extinguishing. <P>SOLUTION: The dome structure 10 is mounted on a storage tank 1 comprising a storage tub 6 for storing a flammable liquid and the floating roof 7 mounted movably inside the storage tub 6. The dome structure 10 comprises the dome part 11 covering the floating roof 7, supports 12 disposed inside the storage tub 6 for supporting the dome part 11, a vent 14 disposed on a leakage preventive panel 13 supported by the supports 12 for making the inside and outside of the dome part communicate with each other, and the ventilation shutting device 15 for shutting the vent 14 when a fire occurs on the floating roof 7. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a dome structure, a storage tank, and a fire extinguishing method for covering a floating roof that is movably provided in a storage tank that stores a combustible liquid such as crude oil.

  As a conventional storage tank, for example, a floating roof structure (floating system) is known that includes a floating roof that moves according to the amount of stored oil in a storage tank that stores oil.

  In this type of storage tank, the vaporized vapor of the oil in the storage tank is released from the seal section provided between the floating roof and the inner peripheral wall of the storage tank, and this vapor is ignited to ignite the steam in the seal section. A so-called ring fire occurs. For this reason, the conventional storage tank is equipped with the fire extinguishing apparatus for initial fire extinguishing on the assumption of the ring fire which is a local fire (for example, refer patent document 1).

  By the way, the conventional storage tank has a structure in which the floating roof is exposed to the outside. Therefore, depending on the installation environment and the weather, the rain accumulated on the floating roof freezes or snow accumulates, and the floating roof with these weights May sink into the storage tank. Therefore, in the conventional storage tank, the cost for removing snow and ice on the floating roof is high as a countermeasure against snow damage in winter. In addition, even when the conventional storage tank is installed in an area where a volcano is located, there is a problem that volcanic ash accumulates on the floating roof and the same measures as described above are required.

Therefore, a storage tank having a dome portion covering the floating roof is desired. A storage tank with a dome that covers the floating roof needs to ensure air permeability inside the dome in order to prevent the flammable liquid vapor discharged from the floating roof from filling the interior of the dome. For example, a support member that supports the dome portion is provided with a vent for ventilating the inside and the outside of the dome portion.
Japanese Unexamined Patent Publication No. 2000-140142 (FIG. 1)

  As described above, in the conventional storage tank provided with the dome part covering the floating roof, since a vent for ventilating the inside and the outside of the dome part is provided, when a fire occurs on the floating roof, When extinguishing a fire by discharging a fire extinguisher to the floating roof, oxygen is supplied to the fire, so that there is a disadvantage that fire extinguishing is not performed smoothly.

  Therefore, the present invention avoids inconvenience due to the environment and weather by the dome portion covering the floating roof, and can quickly and smoothly extinguish a fire generated on the floating roof, a storage tank, and a fire extinguishing method. The purpose is to provide.

  In order to achieve the above-described object, a dome structure according to the present invention is a dome structure provided in a storage tank including a storage tank that stores a flammable liquid and a floating roof that is movably provided in the storage tank. A dome that covers the floating roof, a support that is provided in the storage tank and supports the dome, a vent that is provided in the support and vents the inside and outside of the dome, and a fire on the floating roof And a ventilation block means for blocking the ventilation port when the occurrence of the occurrence of the problem.

  According to the dome structure according to the present invention configured as described above, since the air permeability is ensured by the vent hole, the vapor of the combustible liquid is prevented from being accumulated in the dome portion. And according to this dome structure, when a fire occurs on the floating roof, the vent is shut off, so that the supply of oxygen to the fire is cut off, and the fire can be smoothly extinguished by the suffocation work. It becomes possible.

  The storage tank according to the present invention includes the above-described dome structure of the present invention.

  The fire extinguishing method according to the present invention includes a storage tank that stores a flammable liquid, a floating roof that is movably provided in the storage tank, a dome that covers the floating roof, and a dome provided in the storage tank. Fire extinguishing method used for a storage tank comprising a dome structure having a support body that supports a section and a vent hole that is provided on the support body and vents the inside and outside of the dome section. Sometimes, the ventilation hole is blocked by the ventilation blocking means.

  As described above, according to the present invention, the dome portion covering the floating roof avoids inconvenience due to the environment and the weather, and the fire generated on the floating roof is suppressed by the ventilation block means, and the suffocation extinguishing work is quick and smooth. It becomes possible to extinguish the fire.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, a storage tank 1 according to an embodiment includes a storage tank 6 that stores a flammable liquid such as oil, a floating roof 7 that is movably provided in the storage tank 6, and a floating roof 7. The fire extinguishing equipment 9 for the ring fire for extinguishing the ring fire in the outer periphery of the dome, and the dome structure 10 covering the floating roof 7 are provided.

  The storage tank 6 is formed in a bottomed cylindrical shape, and a floating roof 7 is provided on the inner periphery. The gap between the floating roof 7 and the inner wall of the storage tank 6 is sealed by a seal portion 15 provided on the outer periphery, and the floating roof 7 has a storage amount of the combustible liquid stored in the storage tank 6. Accordingly, it is provided so as to be movable in the height direction along the inner peripheral wall of the storage tank 6.

  The floating roof 7 is configured as a so-called single deck having a single-layer structure, but may be configured as a so-called double deck having a two-layer structure, and mechanical strength and the like may be appropriately improved.

  The fire extinguishing equipment 9 for the ring fire is disposed at the upper end of the storage tank 6, and although not shown, a fire extinguisher tank in which a fire extinguisher is stored and a foam for foaming the fire extinguisher supplied from the fire extinguisher tank And a discharge port for discharging a foam-like fire extinguisher foamed by the foamer. And this fire extinguishing equipment 9 for ring fires makes the foam-like fire extinguisher discharge | released from the discharge port flow down along the inner wall of the storage tank 6, and extinguishes the ring fire in the outer peripheral part of the floating roof 7. FIG.

  As shown in FIGS. 1 and 2, the dome structure 10 includes a dome portion 11 that covers the floating roof 7, a column 12 that constitutes a support member that supports the dome portion 11, and a column 12 provided outside the column 12. A leak prevention plate 13 for preventing the flammable liquid from leaking out, a plurality of vent holes 14 provided in the leak prevention plate 13 for ventilating the inside and the outside of the dome portion 11, and blocking the vent holes 14. A plurality of ventilation blockers 15.

  The dome portion 11 is configured by providing a covering material made of a metal material such as aluminum on the beam 11 a, and the beam 11 a is supported by the support column 12. A floor portion 17 on which the fire extinguishing equipment 9 and the like are disposed is provided on the outer peripheral portion of the upper end portion of the storage tank 6. The support columns 12 are erected on the floor portion 17 at predetermined intervals along the circumferential direction of the storage tank 6.

  The column 12 is provided with a leakage prevention plate 13 horizontally. Each strut 12 is provided with a vertical wall 18 straddling the leakage prevention plate 13 and the floor portion 17 so as to block ventilation inside and outside the dome portion 11. The ventilation holes 14 are arranged adjacent to the leakage prevention plate 13 at a predetermined interval. Each vent hole 14 is provided with a mesh-like screen member 19 that prevents a bird or the like from entering the dome portion 11.

  The ventilation blocker 15 is provided for each group of a plurality of dampers 21 that operate independently. As shown in FIGS. 3A and 3B, the ventilation blocker 15 includes a plurality of dampers 21 movably provided between an open position where the vent 14 is opened and a closed position where the vent 14 is closed. A winch 23 having a wire 22 for opening and closing each damper 21, a rotating drum 23a for winding the wire 22, a stopper 24 for restricting the operation of the winch 23 and fixing the damper 21 in an open position, and the stopper 24 And a stopper moving mechanism 25 that moves.

  The damper 21 is formed in a rectangular plate shape made of a metal material such as an aluminum alloy, for example, and is disposed at a position corresponding to the vent hole 14. One end of the damper 21 is rotatably supported by the support column 12 and is fixed at an open position by the tension of the wire 22 in an initial state. Then, each damper 21 is moved to the closed position when the tension of the wire 22 is released, and closes the plurality of vent holes 14.

  The wire 22 is provided across the plurality of dampers 21, one end is fixed by a fixing member 28, and the other end is attached to the winch 23. The wires 22 are bridged over the wire guides 27 provided on the damper 21 and the beam 11a of the dome portion 11, respectively.

  The stopper 24 is movably provided at an engagement position that engages with an engagement portion provided on the rotary drum 23a and a release position that releases the engagement state. The stopper 24 regulates the movement of the wire 22 by regulating the rotation of the rotary drum 23a. Therefore, when the operation of the winch 23 is restricted by the stopper 24, the tension by the wire 22 is maintained, and each damper 21 is fixed at the open position.

  As shown in FIG. 4, the stopper moving mechanism 25 regulates the supply of gas from the piston 31 and the cylinder 32 that support and drive the stopper 24, the gas cylinder 33 in which, for example, nitrogen gas is accommodated, and the gas cylinder 33. An electromagnetic valve 34 and a coil spring 35 that urges the piston 31 are provided.

  The stopper moving mechanism 25 moves the piston 31 against the urging force of the coil spring 35 with the pressure of the gas supplied from the gas cylinder 33 into the cylinder 32, thereby positioning the stopper 24 at the engagement position. When the stopper moving mechanism 25 moves the stopper 24 to the release position, the gas supplied from the gas cylinder 33 is exhausted from an exhaust pipe (not shown) by the electromagnetic valve 34, and is moved from the gas cylinder 33 to the cylinder 32 by the electromagnetic valve 34. The supply of gas is restricted. For this reason, the stopper 24 is moved to the release position by the biasing force of the coil spring 35, and the winch 23 is operably opened. The stopper moving mechanism 25 described above may be configured to be driven by, for example, a motor or a hydraulic cylinder.

  Regarding the dome structure 10 of the storage tank 1 configured as described above, the operation of blocking the vent hole 14 by the vent blocking device 15 when a fire occurs on the floating roof 7 will be described.

  First, in the storage tank 1, the damper 21 is normally fixed at the open position by the ventilation blocker 15, and the inside of the dome portion 11 is ventilated through the vent hole 14.

  In the storage tank 1, when a fire occurs on the floating roof 7, the ventilation blocker 15 is automatically operated manually or by a fire detector or the like. In the ventilation blocker 15, the stopper 24 is moved to the release position by the stopper moving mechanism 25, so that the rotating drum 23a of the winch 23 can be rotated, and the fixed state of each damper 21 due to the tension of the wire 22 is released. Each damper 21 is rotated to the closed position.

  For this reason, each air vent 14 is obstruct | occluded by each damper 21 rotated to the obstruction | occlusion position, and ventilation | gas_flowing by each air vent 14 is interrupted | blocked, The supply of oxygen to the fire of the floating roof 7 is suppressed. Therefore, the fire of the floating roof 7 is weakened and is smoothly extinguished by the fire extinguishing equipment 9 or the like.

  Further, in this dome structure 10, after the fire of the floating roof 7 is extinguished, if the damper 21, the wire 22, or the like is not damaged by the fire, the wire 22 is wound up by the winch 23 to open the damper 21 to the open position. To return to the initial state.

  As described above, according to the storage tank 1 and the dome structure 10, the storage tank 1 and the dome structure 10 are provided with the ventilation blocking device 15 that blocks the ventilation hole 14 when a fire occurs on the floating roof 7. In addition to avoiding inconvenience due to the installation environment and weather of the tank 1, it is possible to suppress a fire that has occurred on the floating roof 7 by the ventilation blocker 15 and to extinguish the fire quickly and smoothly by the fire extinguishing equipment 9.

  Moreover, according to this storage tank 1 and the dome structure 10, it becomes possible to operate the ventilation blocker 15 by remote operation from the ground, for example, and it is possible to ensure safety during fire extinguishing work.

  In the dome structure 10 described above, the ventilation blocking device 15 is operated so that the ventilation holes 14 are blocked by the dampers 21 after a fire has occurred on the floating roof 7. For example, when an earthquake occurs For example, in order to prevent the occurrence of a fire, the vent 14 may be operated to be blocked by the ventilation blocker 15 before the fire is generated on the floating roof 7.

  In addition, the above-described ventilation blocking device 15 is configured such that the damper 21 rotates by its own weight and closes the ventilation hole 14. For example, as illustrated in FIGS. 5A and 5B, The weight 37 may be arranged at one end. According to this configuration, the damper 21 can be more reliably rotated by the weight 37 to close the vent hole 14.

  Next, another ventilation blocking device will be briefly described with reference to the drawings. In other ventilation blockers, the same members as those in the above-described embodiment are denoted by the same reference numerals for the sake of convenience, and description thereof is omitted.

(Other embodiments)
In the above-described embodiment, the air blocking device 15 is configured to rotate each damper 21 from the open position to the closed position via the wires 22 and winches 23 that support the plurality of dampers 21, but the stopper 24. Alternatively, the damper 21 may be directly supported by the stopper moving mechanism 25.

  As shown in FIGS. 6, 7 (a), 7 (b), and FIG. 8, the ventilation blocker 55 includes a stopper 24 that fixes the damper 21 in the open position for each damper 21, and the stopper 24 is in the release position. And a stopper moving mechanism 25 that moves to the right.

  A cylinder support member 56 that supports the cylinder 32 of the stopper moving mechanism 25 is fixed to the dome portion 11. Each damper 21 is formed with an engagement piece 57 at which the stopper 24 is engaged at a position corresponding to the stopper 24. The engagement piece 57 is provided with an engagement hole 57a through which the stopper 24 is inserted and engaged.

  Further, as necessary, the gas cylinder 33 is configured to supply gas to another cylinder 32 that moves the other stopper 24 via a gas supply pipe (not shown).

  In the ventilation blocking device 55 configured as described above, by driving the stopper 24 and the stopper moving mechanism 25 corresponding to each damper 21, each damper 21 is rotated to the closed position and each ventilation hole 14 is blocked. The

(Still another embodiment)
In the above-described embodiment, the air blocking device 15 includes the stopper moving mechanism 25 that mechanically moves the stopper 24. However, the damper automatically operates when the wire holding member is melted by heat. As described above, a so-called fuse method may be adopted.

  As shown in FIGS. 9A and 9B and FIGS. 10A and 10B, the ventilation blocker 65 includes a wire 22 that supports the damper 21, a wire guide 67 that guides the wire 22, And a wire holding member 68 that holds the wire 22 in a state in which the damper 21 is rotated to the open position.

  One end of each wire 22 is fixed to the damper 21 and is stretched over each wire guide 67. Each wire 22 is inserted through a guide hole 13 a provided in the leakage prevention plate 13, and the other end is fixed to a wire holding member 68 fixed to the support column 12.

  The wire holding member 68 is disposed at a position where the wire holding member 68 is melted by the heat of a fire generated on the floating roof 7.

  In the ventilation block device 65 configured as described above, when a fire occurs in the floating roof 7, the wire 22 is detached from the wire holding member 68 by melting and breaking the wire holding member 68 by the heat of the fire. . For this reason, since the tension | tensile_strength by the wire 22 is cancelled | released, the damper 21 is rotated by the dead weight to the obstruction | occlusion position, and interrupts the vent hole 14. FIG. That is, according to the ventilation block device 65, the damper 21 can be automatically operated when a fire occurs on the floating roof 7. Further, according to the ventilation block device 65, since the above-described stopper moving mechanism 25 and the like are not necessary, the configuration can be simplified.

It is a schematic diagram which shows the storage tank of this embodiment. It is a figure for demonstrating a dome structure, Comprising: (a) is sectional drawing which shows a dome structure, (b) is a side view which shows a dome structure. It is a figure for demonstrating the operation | movement which a ventilation blocker opens and closes a damper, Comprising: (a) is a perspective view which shows the state by which the vent hole was open | released, (b) is a perspective view which shows the state by which the vent hole was obstruct | occluded. It is. It is a schematic diagram which shows a stopper moving mechanism. It is a figure which shows an example of a damper, Comprising: (a) is a perspective view which shows a damper, (b) is sectional drawing which shows a damper. It is sectional drawing for demonstrating another ventilation blocker. It is a figure for demonstrating the operation | movement which opens and closes a damper by another ventilation blocker, Comprising: (a) is a perspective view which shows the state by which the vent hole was open | released, (b) shows the state by which the vent hole was obstruct | occluded. It is a perspective view. It is a schematic diagram which shows another stopper moving mechanism. FIG. 5 is a view for explaining another ventilation block device, in which (a) is a cross-sectional view showing the ventilation block device, and (b) is a side view showing the ventilation block device. Furthermore, it is a figure for demonstrating the operation | movement which opens and closes a damper with another ventilation blocker, Comprising: (a) is a perspective view which shows the state by which the vent hole was open | released, (b) is the state by which the vent hole was obstruct | occluded. It is a perspective view shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Storage tank 6 Storage tank 7 Floating roof 9 Fire extinguishing equipment 10 Dome structure 11 Dome part 12 Support | pillar 13 Leakage prevention board 14 Ventilation hole 15 Ventilation shielding device 21 Damper 22 Wire

Claims (8)

A dome structure provided in a storage tank comprising a storage tank for storing a flammable liquid, and a floating roof provided movably in the storage tank,
A dome covering the floating roof;
A support provided in the storage tank and supporting the dome,
A vent hole provided in the support body for ventilating the inside and the outside of the dome,
A dome structure comprising: ventilation block means for blocking the ventilation hole when a fire occurs on the floating roof.   The dome structure according to claim 1, wherein the storage tank includes a fire extinguishing facility that discharges a fire extinguishing agent to the floating roof.   The ventilation block means has a damper member movably provided in an open position for opening the vent and a closed position for closing the vent, and a moving means for moving the damper member to the closed position. The dome structure according to claim 1 or 2.   The dome structure according to claim 3, wherein the moving unit includes a wire that supports the damper member, and moves the damper member via the wire.   5. The dome structure according to claim 3, wherein the moving means includes a stopper member that fixes the damper member at the open position, and a moving mechanism that moves the stopper member.   The said moving means has a stopper member which fixes the said damper member in the said open position, The said stopper member is arrange | positioned in the position fuse | melted with the heat of the fire which arose on the said floating roof. The dome structure described in 1.   A storage tank comprising the dome structure according to any one of claims 1 to 6. A storage tank that stores a flammable liquid; a floating roof that is movably provided in the storage tank; a dome that covers the floating roof; and a support that is provided in the storage tank and supports the dome. And a fire extinguishing method used in a storage tank provided with a dome structure provided on the support body and having a vent hole that ventilates the inside and outside of the dome part,
A fire extinguishing method, wherein when a fire occurs on the floating roof, the vent is blocked by a ventilation blocking means.

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