JPS627073B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The disclosed technology is a system for draining precipitation on an underground petroleum storage tank having a floating roof from a drainage shaft via a drainage pipe extending from the floating roof. It belongs to a technical field that increases the degree of freedom in planning the start and stop of a drainage pump when draining water to the outside.

<Summary of the gist> Therefore, this invention is a method for collecting precipitation on the floating roof of a floating roof type underground tank storing petroleum by means of a drain pipe extending from the floating roof into the tank body. This invention relates to a drainage device for an underground petroleum storage tank, which drains water to a drainage shaft and further drains water to the outside of the system via a drainage pipe using a drainage pump installed at the bottom of the drainage shaft. The drainage shaft is connected to a vertical drainage shaft constructed in the ground outside the tank body at a predetermined distance from the tank body, so that the water storage level in the drainage shaft is lower than the height of the floating roof. To,
Further, the invention relates to a drainage system for an underground petroleum storage tank, in which the bottom of the drainage shaft is formed at a lower level than the bottom plate of the tank body, and the bottom of the drainage shaft is provided with a switch control device with a water pressure detection mechanism for the drainage pump. It is.

<Prior art> As is well known, there are various types of petroleum storage tanks, but due to various conditions such as pollution and the environment, floating roof tanks and underground tanks have recently been adopted. I'm getting used to it.

As shown in Fig. 1, the floating roof type underground tank 1 is constructed by constructing a continuous underground wall 4 up to the impermeable layer 3 in a predetermined ground 2; A tank body 5 is provided, petroleum 7 is stored on a bottom plate 6, and the tank is operated for receiving and discharging, so that precipitation on a floating roof 8 that rises and lowers along with the receiving and discharging does not overflow from its side edges. A drain pipe 10 extends from the center into the tank body 5 via a rainwater basin 9.
The water is guided into a drainage shaft 11 that also serves as a stopper and is fixedly planted on the bottom plate 6 near one side of the tank body 5, and is then introduced through a drainage pipe 13 by a drainage pump 12 attached to the bottom of the drainage shaft 11. The water was then drained out of the system.

Incidentally, the floating roof 8 can be moved up and down in a fluid-tight manner with respect to the drainage shaft 11 via an appropriate sliding seal.

<Problems to be Solved by the Invention> However, when the floating roof 8 is raised and lowered only a few times, such as in a storage tank, the capacity of the drainage shaft 11 located lower than the floating roof 8 is relatively large. Even if the capacity of the drainage pump 12 is small, it is possible to drain water with an appropriate frequency of starting and stopping, but in the case of regular inspections that occur once every five years, etc., the oil 7 is pumped out and the floating roof 8 is removed, for example. When lowered to a height of about 2 m from the bottom plate 6, if there is a large amount of precipitation during that period, the drainage pump 12 will start and stop more frequently because the internal capacity of the drainage shaft 11 located lower than the floating roof 8 is small. Or, if the system reaches zero capacity due to full operation, there is a risk that drainage will not be possible, and therefore, there is a drawback that it is practically impossible to plan the drainage system with an optimal design. .

In addition, in a service tank or the like, since the floating roof 8 is raised and lowered quite frequently in response to receiving and discharging, the frequency of starting and stopping of the drain pump 12 becomes high, making it difficult to set up a drainage system.

Furthermore, sloshing occurs during an earthquake, and as a result, the drainage shaft 11 provided within the tank body 5 is subjected to shaking vibrations, which may cause damage and have the disadvantage of causing oil leaks during water supply. Ta.

<Object of the invention> The object of the invention is to solve the problem of drainage of the floating roof type underground petroleum storage tank based on the above-mentioned prior art as a technical problem to be solved, and to provide a drainage shaft in the ground outside the tank body. This makes it possible to eliminate the above-mentioned drawbacks, solve the difficulties, eliminate the disadvantages, and make it possible to easily plan drainage systems, thereby creating an excellent underground oil system that benefits the field of tank technology application in the energy industry. The purpose is to provide a drainage system for storage tanks.

<Means and operations for solving the problems> In order to solve the above-mentioned problems, the structure of the present invention, which is based on the above-mentioned claims, is based on a floating roof type underground petroleum storage tank. Precipitation that collects on the roof is led out to the outside of the tank body through a drainage pipe extending downward from the center, drained to a drainage shaft built in the ground outside the tank body, and drained into the drainage shaft. The bottom part is located below the bottom plate of the tank body, and a switch with a water pressure detection mechanism is installed at the bottom of the drainage shaft to adjust the amount of water in the drainage shaft so that the level of the stored water is always below the side edge of the floating roof. The control device detects the amount of water to be adjusted and automatically starts and stops the drainage pump, ensuring that the drainage pump can be started and stopped easily regardless of the height of the floating roof. By installing it outside the building, the drainage shaft may be damaged due to sloshing, etc.
Technical measures have been taken to prevent oil from leaking into the drainage water.

<Embodiment - Configuration> Next, one embodiment of the present invention will be described below based on FIG. 2. Note that the same parts as in FIG. 1 will be explained using the same reference numerals.

Reference numeral 1' denotes a floating roof type underground petroleum storage tank which constitutes the gist of the present invention, and has a continuous underground wall 4 that reaches a difficult-to-permeable layer 3 in a predetermined ground 2, similar to the conventional embodiment described above.
A tank body 5 is provided with a bottom plate 6 in a strong version type, and a floating roof 8 is attached to the upper surface of the stored petroleum 7 so as to be able to be raised and lowered via a pontoon or the like (not shown). .

Reference numeral 11' denotes a hard hole forming a drainage shaft, which is constructed vertically on the outside of the continuous underground wall 4 at a predetermined distance from the tank body 5, and whose bottom part is connected to the bottom plate 6.
A drain pipe 10 extending downward from the center of the floating roof via a rainwater catchment 9 is installed at a lower level by the design level L, and the continuous underground wall 4 is installed as appropriate. The connecting tube 10' is connected to the connecting tube 10' through the connecting tube 10'.

At the bottom of the drainage shaft 11', a switch control device 1 with a pressure detection mechanism for appropriate water pressure is installed.
4 is provided and is electrically connected to the drain pump 12 and a microcomputer (not shown), so that the amount of water in the drain shaft 11' is stored at a level lower than the level l of the floating roof 8 by a set amount at that height. In this case, the drainage pump 12 is operated and the floating roof is adjusted according to the amount of elevation of the floating roof 8 by the appropriate elevation detection device 14' provided on the floating roof 8, which has an adjustable capacity W so as to stop at a level close to zero. Starting and stopping of the drain pump 12 can be controlled by a microcomputer at a water level that is a set amount lower than 8.

The drain pump 12 is configured to drain water in the drain shaft 11' to the outside of the system via a drain pipe 13.

<Embodiment - Effect> In the above-described configuration, when the underground petroleum storage tank 1' is operated with petroleum 7 stored therein and the oil is received and disbursed in a predetermined manner, the floating roof 8 is raised and lowered along with it, and the amount of elevation thereof is is input to the microcomputer together with the amount of water pressure detected by the switch control device 14 with a pressure detection mechanism via the lift amount detection device 14'.

During that time, when precipitation occurs and the precipitation accumulates on the floating roof 8, it flows into the adjustment capacity W portion of the drainage shaft 11' through the drain pipe 10 and the communication pipe 10', and detects the amount of elevation of the floating roof 8. The level l of the floating roof 8 is detected by the input by the device 14, and in the process in which the water volume reaches a part lower than the set level from the level l, the switch control device 14 with a pressure detection mechanism detects the pressure of the water volume, and the microcomputer When the detected amount reaches a water amount that is lower than the set amount, the drain pump 12 is started and the water is drained out of the system via the drain pipe 13 to reduce the water in the drain shaft 11', and a set pressure near zero water amount is detected. and drain pump 12
stops.

In the above process, the drainage capacity of the drainage pump 12 is designed to be greater than the maximum amount of precipitation on the floating roof 8 through measurements, experiments, theoretical calculations, etc.

Therefore, once the drain pump 12 is started, it will not stop until all the internal water volume of the adjusted capacity W has been discharged, and once it has stopped, it will be lowered by a predetermined amount below the level L of the floating roof 8. The microcomputer controls the drainage pump so that it does not start until precipitation has been stored up to the adjusted capacity W up to the height of
During the annual inspection, the number of times the drainage pump starts and stops during rain when the floating roof 8 is at its lowest point is relatively high, but it is possible to freely design the start and stop of the drainage pump within the setting range of the adjustment capacity W. .

In addition, in the case of a service tank, the frequency of raising and lowering the floating roof 8 is higher than that of a storage tank, but the adjustment capacity W, which fluctuates accordingly, can store enough rainwater to reduce the frequency of starting and stopping the drainage pump. It is possible to reduce the amount.

It goes without saying that the embodiments of the present invention are not limited to the above-mentioned embodiments, and various embodiments are possible.In addition, drainage shafts of a predetermined diameter may be provided, or enlarged pits may be provided at the bottom of each drainage shaft. It is also possible to change the design, such as by providing a

<Effects of the Invention> As described above, according to the present invention, in an underground petroleum storage tank having a floating roof, a drain pipe extending downward from the floating roof is connected to a drainage shaft, and a drain pipe is connected to the drainage shaft. By draining water out of the system using a drainage pump installed at the bottom of the tank, precipitation that accumulates on the floating roof is effectively drained out of the tank by the drainage shaft. By installing it at a set distance on the outside of the main body, the tank main body and the drainage shaft can basically be constructed as separate structures, and in the event of an earthquake, the drainage shaft will not be affected by sloshing, etc., and will not be damaged. Furthermore, there is no possibility that petroleum oil will enter into the waste water, and there is no risk of environmental destruction.

Since the drainage shaft is installed on the outside of the tank body, its bottom can be lowered by a set amount than the bottom plate of the tank body, so it is possible to adjust the amount of precipitation stored in the drainage shaft. As a result, a switch control device with a water pressure detection mechanism installed at the inner bottom of the drainage shaft controls the start and stop of the drainage pump so that the precipitation introduced and stored in the drainage shaft is lowered by a set amount than the side edge of the floating roof. Regardless of whether it is a storage tank or a service tank, the frequency of starting and stopping the drainage pump can be set as planned.Therefore, we created a drainage system that allows drainage even when there is a large amount of drainage or when the oil level is low. The excellent effect of being able to do this is achieved.

Also, since the drainage shaft is not inside the tank body,
The structure is simple and there are no sliding parts with the floating roof, so it has the advantage of being easy to manufacture, low initial cost, and easy maintenance.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of an underground petroleum storage tank having a drainage system based on the prior art, and FIG. 2 is a schematic sectional view of one embodiment of the present invention. 5... Tank frame, 8... Floating roof, 10... Drain pipe, 11'... Drain shaft, 12... Drain pump, 13... Drain pipe, 2... Underground, 6... Bottom plate.

Claims (1)

[Claims] 1 A drainage pipe extending from the floating roof inside the tank body is connected to only one drainage shaft attached to the tank body, and a drainage pump installed at the inner bottom of the drainage shaft is connected to the outside of the drainage shaft. In a drainage system connected to a drainage pipe, the drainage shaft is installed in the ground outside the tank body so that its bottom is below the bottom plate of the tank body, and the drainage shaft from the floating roof is connected to the drainage shaft. A switch control device with a hydraulic pressure detection mechanism for the drainage pump is attached to the bottom of the drainage shaft so that the cross-sectional level of rainwater is stored in the drainage shaft at a level below the top surface height of the floating roof. Drainage system for underground petroleum storage tanks.