JPH0510300U - Oil leak prevention device for underground tank - Google Patents

Abstract

(57) [Summary] [Structure] Rigid rising pipes P1, P2, P4 rising from the underground tank 3 where oil is stored, and the rising pipes P1, P
2, rigid conduits 13, 14, 15 to be connected to P4
And vulnerable portions 10, 11 and 12 between them and valve means V1 and V2 for closing the rise pipes P1 and P2 by raising the oil level 16 in the underground tank 3. [Effect] When an earthquake occurs, the fragile parts 10, 11,
By breaking 12 the riser pipes P1, P2,
Prevents external force from acting on P4, thereby preventing deformation or damage of the underground tank 3 and preventing oil in the underground tank 3 from leaking to the outside due to groundwater flowing into the underground tank 3. To do.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an oil leakage prevention device for an underground tank for preventing oil leakage due to flooding of an underground tank that stores oil such as gasoline, light oil or kerosene and damage due to an earthquake.

[0002]

[Prior Art]

 For example, underground tanks that store fuel oil such as gasoline or light oil are buried at gas stations. In this underground tank, the ventilation riser that communicates with the gas phase above the oil level, the oiling riser for receiving oil from the tank truck, and the fuel in the underground tank by the pump installed in the refueling device. The rising pipes for oil supply for pumping oil are firmly connected by welding, for example, and the free end of each rising pipe projects into the pit or manhole formed above the underground tank. A plurality of conduits are connected to the free end of each rising pipe. Each of the conduits is guided from the pit through the ground to the ground surface.

[0003]

[Problems to be solved by the device]

 In such a prior art, when an earthquake occurs, the rising pipe protruding into the pit is pressed or pulled by each conduit, so that a large force is applied to the connecting portion of the underground tank to which each rising pipe is connected. May act and deform, and cracks may occur in the deformed part. When the groundwater level is higher than that in the underground tank, the groundwater flows into the underground tank through the cracks, and the specific gravity of the groundwater is larger than that of the fuel oil stored in the underground tank. The fuel oil level rises as the inflow of groundwater through the crack increases, and the fuel oil leaks to the outside through the rising pipe and the conduit.

Therefore, an object of the present invention is to provide an oil leakage prevention device for an underground tank, which is capable of preventing damage to the underground tank during an earthquake and preventing leakage of fuel oil in the underground tank due to flooding. It is to be.

[0005]

[Means for Solving the Problems]

 The present invention provides a fragile portion between a rigid rising pipe that rises from an underground tank that stores oil and opens in the underground tank, and a rigid conduit that should be connected to this rising pipe. Is located in the underground tank and has a specific gravity less than the specific gravity of the oil, and when the float is displaced upward, it is displaced toward the open end in the riser pipe to close the riser pipe. A device for preventing oil leakage from an underground tank, characterized in that a valve means having a valve body is provided.

[0006]

[Action]

 According to the invention, the riser rising from the underground tank is rigid, and the conduit to be connected to this riser is also rigid. A weak portion is provided between the rising pipe and the conduit, and when the rising pipe and the conduit are displaced in different directions due to an earthquake or the like, the weak portion is broken and a large force acts on the rising pipe from the conduit. It is possible to prevent spillage and prevent damage to the underground tank. In addition, even if groundwater or the like enters through the opening of the rising pipe caused by the breakage of such a fragile portion, the rising pipe is provided with a valve means, so that the inside of the underground tank is opened through the opening of the rising pipe. Even if the oil level rises due to the water flowing into the riser pipe, the rising pipe is closed by the valve when the oil level reaches the float. This can prevent oil in the underground tank from leaking through the rising pipe.

[0007]

【Example】

 FIG. 1 is a sectional view showing the overall construction of an embodiment of the present invention. For example, in a gas station, a pit 2 is formed on the road surface 1, which is the ground surface, and below the pit 2, an underground tank 3 for storing fuel oil such as gasoline, light oil or kerosene is provided. The underground tank 3 is made of steel, for example, and has a capacity of 10 to 30 klitres. A plate-shaped steel lid 4 is fitted in the pit 2 so as to be substantially flush with the road surface 1. The lid 4 has a plurality of (2 in this embodiment) monitoring holes 5, 6 are formed, and monitoring lids 7 and 8 are detachably fitted in these monitoring holes 5 and 6.

In the pit 2, a plurality (4 in this embodiment) of rising pipes P1 to P4 are provided. Among these rising pipes P1 to P4, a ventilation rising pipe P1, an oiling rising pipe P2, and Flange short pipes 10, 11 and 12 made of steel, which are fragile parts, are flange-joined to the refueling riser pipe P4, and conduits 13, 14 and 15 are flanged to the fracture short pipes 10 to 12, respectively. To be joined.

The conduit 13 connected to the rising pipe P1 for ventilation through the short pipe 10 for breaking is opened via a flame arrester (not shown) for preventing ignition above the road surface 1, and the underground pipe is opened. The gas phase 17 above the oil level 16 in the tank 3 is open to the atmosphere. This prevents the gas phase 17 from becoming negative pressure when the oil level 16 drops, and discharges the air in the gas phase 17 and the vaporized gas of the fuel oil when the oil level 16 rises, and It is possible to prevent the pressure in the tank 3 from rising and to smoothly supply or suck the fuel oil into the underground tank 13.

The conduit 14 connected to the oiling riser pipe P2 via the short pipe 11 for breaking has a tip end projecting above the road surface 1 and a coupling 18 is attached to the conduit 14, A hose can be connected for lubrication.

A fuel gauge 19 is attached to the upper end of the fuel gauge mounting riser P3, and the displacement of the float 20 due to the rise or fall of the oil level 16 is transmitted by a wire 21. The storage amount of the fuel oil stored in the underground tank 3 can be measured according to the winding amount of. The amount of fuel oil stored by the fuel gauge 19 can be easily visually checked by removing the monitoring lid 8.

Further, the conduit 15 connected to the refueling rising pipe P4 via the short rupture pipe 12 is connected to a pump for pumping a refueling device (not shown), and driving of the pump causes the inside of the underground tank 3 to be pumped. It is configured to be able to pump up the fuel oil of and to refuel.

Next, a specific configuration of each rising pipe P1, P2, P4 will be described in more detail.

FIG. 2 is an enlarged sectional view of the ventilation rising pipe P1 and its vicinity. The ventilation rising pipe P1 is inserted into a main pipe 23 having a branch pipe 22 to which the breaking short pipe 10 is flange-joined, and a top plate 24 of the tank 3 so as to project into the tank and have a plate-like reinforcing member 25. The connection pipe 26 is fixed by welding in a state of being reinforced by, and the insertion pipe 27 that is inserted into the connection pipe 26 and has the other end protruding downward from the connection pipe 26. A valve means V1 is provided at the lower end of the insertion pipe 27 protruding into the underground tank 3. In the valve means V1, when the float 30 is angularly displaced in the arrow D1 direction and rises, the valve body 31 is angularly displaced in the arrow D2 direction toward the open end side, and the lower end portion of the insertion tube 27 is shown. The valve hole 32 formed in 1 is closed from the vent hole side. Therefore, when the oil level 16 is below the float 30, the valve body 31 is separated from the valve hole 32 by the weight of the float 30, and in such an open state, the oil level 16 rises. The gas in the gas phase 17 and the vaporized gas of the fuel oil can be released to the atmosphere.

The insertion pipe 27 provided with such valve means V 1 is inserted from above into the connection pipe 26 that is fixed in advance to the top plate 24 of the underground tank 3, and the flange 33 of the insertion pipe 27 is the flange of the connection pipe 26. The main pipe 23 is mounted in a state of being supported on 34, and the flange 33 is clamped between the flanges 34 and 35, and is flange-sealed with bolts and nuts (not shown) in an airtight state. To be done. An end plate 37 is fixed to the upper flange 36 of the main pipe 23, and the upper portion of the main pipe 23 is closed.

The short pipe 10 for breaking is connected to the branch pipe 22. A V-shaped notch 38 is formed in the straight pipe portion of the breaking short pipe 10 over the entire circumference in the circumferential direction. Therefore, the portion where the notch 38 is formed is thin. If the conduit 13 and the branch pipe 22 are relatively displaced from each other in the event of an earthquake or the like, the breaking short pipe 10 can be broken at the portion where the notch 38 is formed. When the breaking short pipe 10 is broken in this way, groundwater, rainwater, etc. enter through the opening and flow into the underground tank 3. Due to the inflow of such rainwater, the fuel oil in the underground tank 3 has a specific gravity smaller than that of water, and therefore, the amount of water flowing into the underground tank 3 rises. 31 closes the valve hole 32. Therefore, the water does not flow into the underground tank 3, and the fuel oil located above the water in the underground tank 3 can be prevented from leaking to the outside. Moreover, as described above, there is no risk that external force will act on the rising pipe P1 from the conduit 13 due to the breaking of the short pipe 10 for breaking, and therefore a large force from the rising pipe P1 will act on the tank 3, especially the top plate 24. Instead, damage to the underground tank 3 can be prevented.

FIG. 3 is an enlarged sectional view of the oiling rising pipe P2 and its vicinity. The oil rising pipe P2 is preliminarily reinforced by a main pipe 42 having a branch pipe 41 to which the breaking short pipe 11 is flange-joined and a plate-like reinforcing member 43 on the top plate 24 of the underground tank 3 in advance. The connection pipe 44 is fixed by welding or the like, and the insertion pipe 45 is inserted into the connection pipe 44. The lower end of the insertion pipe 45 extends to the vicinity of the bottom plate 49 (see FIG. 1) of the tank 3, and valve means V2 is provided near the top plate 24. The valve stage V2 has a configuration similar to that of the valve means V1 described above, and the valve body 47 is angularly displaced toward the opening end in the direction of arrow D4 by raising the float 46 in the direction of arrow D3. A valve hole 48 provided downstream of the valve body 47 in the fuel oil inflow direction A is configured to be closed from the coupling 18 side.

The outer peripheral surface of the insertion pipe 45 and the inner peripheral surface of the connection pipe 44 are separated from each other with a slight gap, and form an annular space 50. An inward conduit 51 that opens toward the space 50 is formed in the insertion tube 45, and is connected via a flexible tube 52 to an insertion tube 53 formed near the upper end of the main tube 42. A valve seat 54 is formed so as to project from the upper end portion of the inner insertion tube 53, and the valve body 55 is seated to block the valve hole 56. The valve body 55 is fixed to one end of the valve rod 57 in the axial direction, and a handle 58 is fixed to the other end of the valve rod 57 in the axial direction. The valve rod 57 is inserted and guided through the insertion hole 60 of the end plate 59 fixed to the main pipe 42. The insertion tube 53 in which the valve hole 56 is formed is integrally formed with a partition wall 62 that partitions the internal space 63 of the main tube 42 and the valve chamber 61 in which the valve body 55 is provided. A communication hole 64 that connects the internal space 63 of the main pipe 42 and the valve chamber 61 is formed in the.

A hose from a tank truck is connected to the coupling 18, and fuel oil is supplied from the rising pipe P2 into the underground tank 3 through the conduit 14 and the short pipe 11 for breaking to raise the oil level 16. When the float 46 rises, the valve body 47 closes the valve hole 48 and becomes full. At this time, since the fuel oil from the tank lorry is filled in the pipeline on the upstream side of the fuel oil inflow direction A with respect to the valve body 47, the coupling 18 cannot be loosened and the hose of the tank lorry cannot be removed. Further, it is dangerous that the fuel oil is filled upstream of the valve body 47 in the closed state in the inflow direction A. Therefore, it is necessary to drain the fuel oil in the pipeline. In order to remove such fuel oil, the operator pulls the handle 58 upward, so that the valve body 55 separates from the valve seat 54 against the spring force of the spring 65, and the valve hole 56 opens. Connect to 61. As described above, the valve hole 56 communicates with the opening 66 of the inward conduit 51 facing the space 50 through the flexible tube 52 and is located above the valve chamber 61 shown in FIG. The oil in the conduit 14 can be guided to the gas phase 68 through the valve chamber 61, so that the oil upstream of the coupling 18 flows into the underground tank 3 and the hose loosens the coupling 18. It can be removed.

A short pipe 11 having the same structure as that of the short pipe 10 for breakage described above is connected to the branch pipe 41, and the outer peripheral surface of the right cylindrical portion of the short pipe 11 has a V-shape. The notch 69 is formed over the entire circumference in the circumferential direction to form a thin portion. By providing such a short pipe 11 for breaking, when the branch pipe 41 and the conduit 14 are relatively displaced in the event of an earthquake or the like, the branch pipe 41 is broken and a large force acts on the rising pipe P2. Can be prevented. Therefore, there is no possibility that the underground pipe 3 and especially the top plate 24 will be damaged by a large force acting from the rising pipe P2. Moreover, even if groundwater or rainwater from the outside enters through the opening due to the breakage of the short pipe 11 for breaking, the water flows into the tank 3 until it rises to the oil level 67 when the tank is full. However, there is no risk that the fuel oil above will flow out from the rising pipe P2 to the outside by shutting off the valve means V2. Further, since the valve body 55 elastically abuts and shuts off the valve seat 54 by the spring force of the spring 65, the valve body 55 enters the valve chamber 61 through the space 50, the opening 66 and the valve hole 56. There is no risk of fuel oil leaking out of the tank 3. The installation height of the valve means V2 is set so that the valve means V2 opens at an oil level lower than that of the valve means V1.

FIG. 4 is an enlarged sectional view of the refueling rising pipe P4 and its vicinity. The refueling rising pipe P4 is preliminarily reinforced by a main pipe 72 having a branch pipe 71 to which the breaking short pipe 12 is connected, and a plate-like reinforcing member 76 on the top plate 24 of the underground tank 3 in advance. The connecting pipe 73 is fixed by welding or the like. The main pipe 72 has a diameter smaller than that of the connecting pipe 73, and an end plate 74 that closes the connecting pipe 73 is inserted and airtightly connected. At the lower end of the connecting pipe 73, a check valve 77 is attached, which extends to the vicinity of the bottom plate 49 of the underground tank 3. This check valve 77 is provided with a spherical valve body 78, a rod-shaped stopper 80 fixed to the valve body 78 via a connecting piece 79, and a valve seat 91 on which the valve body 78 is seated. And a valve seat member 92 screwed to the lower end portion of 72. When the suction operation of a pump (not shown) provided in the oil supply device is started, the valve body 78 rises in the suction direction B and is separated from the valve seat 91, and the valve surrounded by the valve seat 91 is surrounded. The hole 93 is opened. Through holes 94 and 95 are formed in the valve seat member 92 and communicate with the chamber 96 on the upstream side in the suction direction B. Therefore, when the pressure in the main pipe 72 decreases due to the start of the suction operation of the pump, the fuel oil in the underground tank 3 flows into the chamber 96 through the through holes 94 and 95, and further through the valve hole 93. The inside of 2 is raised in the direction of arrow B and sucked.

The upper end of the main pipe 72 is closed by an end plate 97. Further, the breaking short pipe 12 having the same structure as the breaking short pipes 10 and 11 described above is connected to the branch pipe 71. A V-shaped notch 98 is formed on the outer peripheral surface of the right cylindrical portion of the short tube 12 for breaking over the entire circumference in the circumferential direction to form a thin portion. Therefore, when the conduit 15 and the branch pipe 71 are relatively displaced from each other in the event of an earthquake or the like, the breaking short pipe 12 is broken at the notch 98, which causes a large external force to act on the refueling rising pipe P4. Therefore, it is possible to prevent the top plate 24 of the underground tank 3 from being damaged.

In the above-described embodiment, a single notch 38, 69, 98 is formed on the fragile short pipe 10, 11, 12 over the entire circumference in the circumferential direction. As another embodiment of the present invention, a plurality of the notches 38, 69, 98 may be formed at intervals in the tube axis direction, and the shape thereof is not limited to the V-shape, but is a U-shape. It is also possible to appropriately select and use any shape such as a shape and a concave shape.

[0024]

[Effect of the device]

 According to the present invention, since the fragile portion is provided between the rigid rising pipe and the rigid conduit, even if the rising pipe and the conduit are displaced from each other due to an earthquake, the fragile portion is weakened. There is no risk that the pipe will break and a large force will act on the riser pipe. This will prevent damage to the underground tank to which the riser pipe is connected. Further, since the rising pipe is provided with a valve means that closes due to the rise of the oil level in the underground tank, even if groundwater or the like flows into the rising pipe from the fragile portion that was broken during the earthquake, the valve means shuts off. It is possible to prevent oil such as fuel oil from flowing out from the underground tank.

[Brief description of drawings]

FIG. 1 is a sectional view showing the overall configuration of an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a ventilation rising pipe P1 and its vicinity.

FIG. 3 is an enlarged cross-sectional view of a rising pipe for lubrication P2 and its vicinity.

FIG. 4 is an enlarged sectional view of a refueling rising pipe P4 and its vicinity.

[Explanation of symbols]

 3 Underground tanks 10, 11, 12 Breaking short pipes 13, 14, 15 Conduit 16 Oil level P1 Aeration riser pipe P2 Lubrication riser pipe P3 Fuel gauge riser pipe P4 Refueling riser pipe V1, V2 Valve means

Claims (1)

[Claims for utility model registration] [Claim 1] Between a rigid rising pipe rising from an underground tank where oil is stored and opening in the underground tank, and a rigid conduit to be connected to the rising pipe. , A fragile portion is provided, the rising pipe is located in the underground tank, and has a specific gravity less than the specific gravity of the oil, and to the opening end side in the rising pipe when the float is displaced upward. An oil leakage prevention device for an underground tank, comprising valve means having a valve body that is displaced to close the rising pipe.