JPH0738236Y2 - Oil leak prevention device for underground tank - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 storing oil such as gasoline, light oil or kerosene and damage due to an earthquake.

[0002]

2. Description of the Related Art For example, an underground tank for storing fuel oil such as gasoline or light oil is buried in a gas station. In this underground tank, the rising pipe for ventilation that communicates with the gas phase above the oil level, the rising pipe for lubrication for receiving lubrication from the tank truck, and the fuel oil in the underground tank by the pump provided in the oil supply device Refueling rising pipes for pumping are firmly connected by, for example, welding, and the free end of each rising pipe projects into a 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]

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 each rising pipe of the underground tank is A large force may be applied to the connecting portion to be connected and deformed, and a crack may occur in the deformed portion. When the groundwater level is higher than that of 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 oil level of the fuel oil rises as the amount of groundwater flowing 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]

DISCLOSURE OF THE INVENTION The present invention relates to a rigid rising pipe rising from an underground tank in which 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 when the float is displaced upward, the float pipe is moved toward the opening end side in the rising pipe. An oil leakage prevention device for an underground tank, comprising valve means having a valve body that is displaced to close the rising pipe.

[0006]

According to the invention, the rising pipe rising from the underground tank is rigid, and the conduit to be connected to this rising pipe 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 damage to the underground tank. 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 the valve means, so that the underground pipe is opened through the opening of the rising pipe. Even if the oil level rises due to the flowing water, when the oil level reaches the float, the rising pipe is closed by the valve body. This can prevent the oil in the underground tank from leaking through the rising pipe.

[0007]

1 is a sectional view showing the overall construction of an embodiment of the present invention. For example, in a gas station or the like, 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. This underground tank 3 is made of steel, for example, and has a capacity of 10 to 30 kL. A plate-shaped steel lid 4 is fitted in the pit 2 so as to be substantially flush with the road surface 1, and a plurality of (in this embodiment, 2) monitoring holes 5, 6 are fitted in the lid 4.
Is formed, and these monitoring holes 5 and 6 have a monitoring lid body 7,
8 is detachably fitted.

In the pit 2, a plurality of (4 in this embodiment)
Riser pipes P1 to P4 of these riser pipes P
Of the 1 to P4, the ventilation rising pipe P1, the oiling rising pipe P2, and the oiling rising pipe P4 are flange-jointed with short steel breaking pipes 10, 11, 12 which are fragile parts, respectively. Pipes 13, 1 are provided for the short pipes 10-12 for breaking.
4 and 15 are respectively flange-joined.

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

A short pipe 11 for breaking is added to the rising pipe P2 for lubrication.
The pipe 14 connected via the above has a coupling 18 attached to its tip end projecting above the road surface 1, and a hose from a tank truck can be connected to perform lubrication.

Further, a fuel gauge 19 is attached to the upper end of the rising pipe P3 for attaching a fuel gauge, 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. The amount of fuel oil stored by the fuel gauge 19 can be easily visually checked by removing the monitoring lid 8.

Further, a conduit 15 connected to the refueling rising pipe P4 via a short pipe 12 for breaking is connected to a pump for pumping a refueling device (not shown), and by driving the pump, inside the underground tank 3. The fuel oil is pumped up for refueling.

Next, the specific construction 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 a plate-shaped reinforcing member 25. The connecting pipe 26 is fixed by welding in a state of being reinforced by, and the inserting pipe 27 that is inserted into the connecting pipe 26 and has the other end protruding downward from the connecting pipe 26. The valve means V1 is provided at the lower end of the insertion pipe 27 protruding into the underground tank 3. When the float 30 is angularly displaced in the arrow D1 direction and lifted, the valve means V1 is angularly displaced toward the opening end in the arrow D2 direction to form the valve means V1 at the lower end of the insertion tube 27. The formed valve hole 32 is closed from the vent side. Therefore, when the oil surface 16 is below the float 30, the valve body 3
1 is separated from the valve hole 32 by the weight of the float 30, and in such a valve-opened state, the gas in the gas phase 17 and the vaporized gas of the fuel oil are released to the atmosphere even if the oil level 16 rises. be able to.

The insertion pipe 27 provided with the valve means V1 as described above is inserted from above into the connection pipe 26 which is previously fixed 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. 34, the main pipe 23 is mounted while being supported on 34, and the flanges 33 are attached to the respective flanges 3.
In the state of being sandwiched between 4 and 35, flange joining is performed in an airtight state by using bolts and nuts (not shown).
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 branch pipe 22 has the short pipe 10 for breaking.
Are connected. 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. When an earthquake occurs, the conduit 13 and the branch pipe 2
When it is relatively displaced with respect to 2, the short tube 10 for breaking can be broken at the portion where the notch 38 is formed. When the short pipe 10 for breaking is broken in this way, groundwater, rainwater, or the like enters through the opening and flows into the underground tank 3. Due to the inflow of rainwater, the fuel oil in the underground tank 3 has a specific gravity smaller than that of water, so that the amount of the fuel oil rises, and finally the oil level 16 reaches the float 30 and the valve element 31 is The valve hole 32 is closed. Therefore, the water does not flow into the underground tank 3, and it is possible to prevent the fuel oil located above the water in the underground tank 3 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, particularly the top plate 24. However, it is possible to prevent damage to the underground tank 3.

FIG. 3 is an enlarged sectional view of the oiling rising pipe P2 and its vicinity. The rising pipe P2 for lubrication is welded in advance with the main pipe 42 having the branch pipe 41 to which the short pipe 11 for breaking is flange-joined and the top plate 24 of the underground tank 3 being reinforced by the plate-like reinforcing member 43. The connecting pipe 44 fixed by the connecting pipe 44 and the inserting pipe 45 inserted into the connecting pipe 44. The lower end of the insertion pipe 45 is connected to the tank 3
The bottom plate 49 (see FIG. 1) of the top plate 2 and
A valve means V2 is provided in the vicinity of 4. This valve means V2
Has substantially the same structure as the valve means V1 described above, and the valve body 47 is angularly displaced toward the opening end side in the direction of arrow D4 by the rise of the float 46 in the direction of arrow D3 so that the fuel is discharged more than the valve body 47. The valve hole 48 provided on the downstream side of the 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. The insertion tube 45 is formed with an inward conduit 51 that opens toward the space 50,
It 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 grip 58 is fixed to the other axial end portion of 7. Valve rod 5
7 is guided through the insertion hole 60 of the end plate 59 fixed to the main pipe 42. 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 pipe 42 and the valve chamber 61 in which the valve body 55 is provided. A communication hole 64 that communicates with the valve chamber 61 is formed.

A hose from a tank truck is connected to the coupling 18, 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, and the float 46 is generated by the rise of the oil level 16. 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 pipe line 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. , The valve body 4 in the closed state again
It is dangerous that the fuel oil is filled upstream of the inflow direction A with respect to 7. 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 to move the valve body 55.
Is separated from the valve seat 54 against the spring force of the spring 65, and the valve hole 56 communicates with the valve chamber 61. The valve hole 56 is provided in the space 5 of the inward conduit 51 via the flexible tube 52 as described above.
The valve chamber 6 shown in FIG. 3 communicates with the opening 66 facing 0.
The oil in the conduit 14 located above 1 is replaced by the valve chamber 6
1 can be led to the gas phase 68, whereby the oil upstream of the coupling 18 can flow into the underground tank 3 and the hose can be removed by loosening the coupling 18.

The branch pipe 41 is connected with a short pipe 11 having the same structure as the breaking short pipe 10 described above.
A V-shaped notch 69 is formed on the outer peripheral surface of the right cylindrical portion of the short pipe 11 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 from each other during an earthquake or the like, the branch pipe 41 is broken from the notch 69,
It is possible to prevent a large force from acting on the rising pipe P2. Therefore, there is no possibility that a large force acts on the underground tank 3, particularly the top plate 24, from the rising pipe P2 to damage it. 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. , Valve means V2
There is no possibility that the fuel oil above will flow out from the rising pipe P2 due to the interruption of the above. Further, since the valve element 55 elastically abuts and shuts off the valve seat 54 by the spring force of the spring 65, the tank is placed in the valve chamber 61 through the space 50, the opening 66 and the valve hole 56. There is no risk that the fuel oil in 3 will leak out. 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 a main pipe 72 having a branch pipe 71 to which the breaking short pipe 12 is connected.
And a connection pipe 73 that is fixed to the top plate 24 of the underground tank 3 by welding or the like in advance while being reinforced by the plate-shaped reinforcing member 76. The main pipe 72 is a connection pipe 73.
The diameter is smaller than that of the above, and the end plate 74 that closes the connection pipe 73 is inserted and airtightly connected. At the lower end of this connecting pipe 73,
The check valve 77 extends to the vicinity of the bottom plate 49 of the underground tank 3.
Is installed. The check valve 77 has a spherical valve body 7
8, 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 that is threadedly attached to the lower end of the main pipe 72.
Have and. 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 separates from the valve seat 91, and the valve hole 93 surrounded by the valve seat 91. Is released. The valve seat member 9
2, through holes 94 and 95 are formed, 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 passes through the through holes 94 and 95 and enters the chamber 96.
To the inside of the main pipe 72 through the valve hole 93, and is lifted up in the direction of arrow B to be sucked.

The upper end of the main pipe 72 is closed by an end plate 97. The branch pipe 71 includes the short pipe 1 for breaking described above.
A short tube 12 for breaking having the same structure as 0 and 11 is connected. On the outer peripheral surface of the right cylindrical portion of the short tube 12 for breaking, V
A V-shaped notch 98 is formed 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 short pipe 12 for breaking is broken at the notch 98, whereby a large external force acts on the rising pipe P4 for refueling. It is possible to prevent the top plate 24 of the underground tank 3 from being damaged.

In the above-described embodiment, the single short notches 38, 69, 98 are formed in the fragile short pipes 10, 11, 12 over the entire circumference in the circumferential direction. In another embodiment, the notch 38,
A plurality of 69 and 98 may be formed at intervals in the tube axis direction, and the shape thereof is not limited to the V shape, and any shape such as a U shape or a concave shape may be appropriately selected and used. You may

[0024]

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 in the event of an earthquake or the like. ,
There is no possibility that the weak portion is broken and a large force acts on the rising pipe. This can prevent damage to the underground tank to which the rising 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,
By shutting off the valve means, oil such as fuel oil can be prevented from flowing out of 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 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 cross-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)

[Scope of utility model registration request] 1. A fragile portion is provided between a rigid rising pipe that rises from an underground tank in which oil is stored and opens in the underground tank, and a rigid conduit that should be connected to the rising pipe. The pipe has a float located in the underground tank and having a specific gravity less than that of the oil, and when the float is displaced upward, the float is displaced toward the opening end side in the rising pipe to close the rising pipe. An oil leakage prevention device for an underground tank, which is provided with a valve means having a valve body that operates.