JPS59163185A - Underground tank of oil station - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to underground tanks for gas stations. As is well known, at a gas station there are tanks buried underground that store the oil to be refueled. Therefore, the underground tank is connected to zero number of pipes inside the underground tank from above ground. The piping includes an oil supply pipe that supplies oil to an underground tank, a fuel supply pipe that supplies oil from the underground tank to a refueling machine, and an air vent pipe.

The underground tank is buried underground1, and the surface above it is hardened with concrete. In addition, piping may crack or be damaged due to vibrations such as earthquakes. If cracks or damage occur in the pipes, water will leak into the underground tank in the event of a flood or high groundwater level.

Cracks and damage in the pipes can be repaired relatively easily by simply taking care of the pipes [However, in order to remove the water that has flowed into the underground tank, the underground tank must be emptied. In addition, oil contaminated with water or dirt cannot be used anymore, and its disposal is extremely troublesome.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an underground tank for a gas service station that minimizes the amount of water flowing into the tank from the outside when cracks or damage occur in the piping.

According to the present invention, a valve is provided in the middle of a pipe connected to an underground tank, and the valve is closed by a water detection signal from a water inflow detection means installed in the underground tank.

However, if a crack or breakage occurs in the piping due to an earthquake or the like, the water flowing into the piping will be blocked by the valve and will not flow into the underground tank.

In implementing the present invention, a liquid level gauge can be used as the water flow person detection means. In other words, the liquid level in the underground tank should not change substantially except during or during refueling operations. Therefore, the liquid level is measured every fixed period of time, for example, 30 seconds, and if the liquid level reaches one level even though no lubrication or refueling is performed, it is determined that water has flowed into the tank.

However, due to temperature changes or other measurement errors, for example,
Since slight changes in measured values occur, an error range is determined in advance, and an accident is assumed to have occurred when the liquid level changes beyond the error range. However, other optional water person detection means may be utilized.

The present invention will be described in detail with reference to the drawings.

FIG. 1 shows a filling station in which the present invention is implemented, and in the figure,
The filling station site S is paved with concrete C.
An underground tank 1 is buried underground. In the illustrated example, three pipes are connected to this underground tank 1. That is, the oil supply pipe 2 is for sending the oil in the underground tank 1 to the oil supply machine 3 installed on the ground, and the oil supply pipe 4 is for supplying oil from the lorry (not shown) to the underground tank 1. In the opening 5, there is an oil switch W.
1 is provided so that it can be detected that oiling work is in progress. Furthermore, an air vent pipe 6 is provided.

Each of these pipes 2.4 and 6 has a valve Vl in the middle.
, V2 and ■3 are provided. As will be described later, these valves Vl, V2, and V3 all prevent water from flowing in, so it is preferable that they be provided at a location as close to the underground tank 1 as possible in the middle of the piping.

The nozzle hook 7 of the refueling machine 3 is provided with a nozzle switch SW2 for detecting that refueling work is in progress.

An office F is installed at the gas station, and an operating device 8 is installed inside the office F. This operating device 8 receives an analog liquid level signal from a liquid level detector 9 installed in the underground tank 1 and converts it into a digital liquid level signal by an A-D converter 10, and is a control device to be described later. Control and display meter 11
The information is displayed at the same time as being printed by the printer 12. In the figure, 13 is a keyboard. As this liquid level detector, it is preferable to use a capacitive liquid level measuring electrode. In the case of this capacitance type, the A=D converter 10 is one that converts capacitance into frequency.

However, when implementing the present invention, a water detection means is provided at the bottom of the tank instead of a liquid level detector, and the water detection means is
Since oil is an insulator and water is a conductor, an electrode can be short-circuited by water, thereby detecting water.

Next, the present invention will be explained in detail with reference to FIG. In FIG. 2, components corresponding to those in FIG. 1 are given the same reference numerals.

The analog liquid level signal from the liquid level detector 9 is converted into a digital liquid level signal by the AD converter 10 and sent to the control device 20 via the AND gate 21. Control device 2
At 0, an 81 rod-type memory circuit 22 indicates the relationship between the liquid level and the liquid amount.
is converted into a liquid amount, and the liquid amount is displayed on the display 11, and the printer 12 is displayed by operating the keyboard 13.
It is now possible to print. The AND gate 21 is opened in response to a signal from the control device 20 at predetermined time intervals, for example, every 30 seconds, so that a liquid level signal is input to the control device at predetermined time intervals. Whether or not the gas station is performing refueling work or oil filling work can be known from the nozzle switches SW, z or the oil filling port switch SW1. In other words, when the oil filler port cover is open, the oil filler switch SW is activated.
A signal arises from I, which is applied to flip-flop circuit 2
3 to the control device 20 to detect that oiling work is in progress. This flip-flop circuit 23 is also reset by a reset signal sent from the control circuit 20 at regular intervals after the lid is closed. When the nozzle is removed, the nozzle switch SW2 generates a signal indicating that refueling is in progress, and this signal is sent to the control device via the flip-flop circuit 24 to detect that refueling is in progress.

This flip-flop circuit 24 is also reset by a signal from the control device. These switches SW
While signals are being output from t and pWz, liquid level comparison work is not performed as will be described later. The liquid level signal from the liquid level detector 9 is calculated based on the calculation formula stored in the calculation formula storage circuit 22 as described above, converted into a liquid volume signal, and updated and stored in the liquid volume storage circuit 25. The liquid amount is then displayed on the display meter 11.

When there is no signal from the switches SW1 and SW2, that is, when no lubrication work or refueling work is performed, the liquid level signal from the liquid level detector 9 is based on the 81 formula stored in the subtraction type storage circuit 22. is calculated and converted into a liquid volume signal, and this liquid volume signal is stored in the flow rate storage circuit 25.

Next, when the AND gate 21 is opened by a signal from the control device 20, the liquid amount signal calculated from the input liquid level signal and the previous liquid amount signal are compared in the control device 20. If this comparison value exceeds a certain error range α, the control device 20 issues a valve closing signal to the valves V1, V2, V'3, and closes the eight valves V1, V2, 3. Alarm 2 at the same time
6 indicates an abnormality. That is, if an abnormality is notified by the alarm 26, it is known that water has entered the tank, oil has leaked due to damage to the tank, or theft. If the alarm informs you of an abnormality, check the abnormality and check the multiplication v1
, v2, and V3.

Next, the present invention will be explained in detail with reference to FIG.

When the detection work of the control device 20 starts (step S1
). At regular intervals (for example, 30 seconds) from the control device 2o,
The goo 1 ~ open signal is transmitted to the ando goos 1 ~ 21 (step 52) a When the AND gate 21 is opened, the signal from the liquid level sensor converted into a digital signal by the A'-D converter 1o is transferred to the AND gate 21. The control [l is input to the device 2o via the (step 83). This liquid level signal is calculated by a subtraction formula stored in the subtraction formula storage circuit 22 to calculate the liquid amount (step 84). Liquid volume memory circuit 25
The previous storage liquid volume (30 seconds ago) is input to the controller 111F20, and in the control device 2o, "storage liquid volume + α", which takes into account the error α with respect to the storage liquid volume, is compared with the current liquid volume (step Ss). The liquid volume this time is “memory liquid volume 1α”
If the oil in the Rinawara tank has increased, then the lubricant is being refilled, and the lid of the opening 5 of the lubricant pipe 4 is opened, and a signal indicating that the lubricant is being refilled is sent. middle switch.

The signal is transmitted from S W t to the flip-flop circuit 23, and it is determined whether the signal is transmitted from the circuit 23 to the control device 20 (step Ss). If lubrication is not in progress, water, etc. has entered from outside, so control device 2
0 generates a valve close signal, which closes the valves V1 to V3 and activates the alarm 26 (step 87). If the alarm 26 is activated, immediately inspect it, find the cause of the abnormality, and repair it.

If lubricating work is in progress in step S6, a signal from the control device 20 resets the flip-flop circuit 23 (step s8), and the value stored in the liquid volume storage circuit 25 is updated to the currently calculated liquid level value. (step Ss
). Then, the process returns to step S2 again. In J3 step S8, the reset signal of the flip-flop circuit 23 is sent at fixed time intervals similar to the open signal of the AND gate circuit 21, so if the lubricating operation is in progress or ends slightly earlier than the fixed time, the reset signal of the flip-flop circuit 23 is transmitted at fixed time intervals. A signal indicating that replenishment is in progress is input.

Now, in step S5, if it is not larger than "storage liquid amount + α", it is determined whether or not it is smaller than "l storage liquid amount - α" (step S to ). If it is not smaller than "memory fluid amount - α", J5 goes to step S5 and "
Not larger than storage liquid amount +α1, and step S +O
If it is not smaller than "storage fluid amount - α", it means that there is no abnormality, so the process returns to step s2.

If it is smaller than "memory liquid amount - α" in step S+o, it means that refueling is in progress, and the nozzle switch SW of refueling 113
No. 43 indicating that refueling is in progress from Z is transmitted to the flip knob circuit 24, and from the circuit 24 the control device 2o
It is determined whether the signal is being transmitted to the
11). If refueling is not in progress, the amount of oil in the tank has decreased due to an abnormality, and the alarm 26 is activated (step 512). If refueling is in progress, the flip-flop circuit 24 is reset (step 513), and the liquid amount stored in the liquid amount storage circuit 25 is updated to the current calculated value (step 514). This step S13 is also step S8
Similarly, when refueling is in progress or the refueling operation has just finished, a signal indicating that refueling is in progress is inputted via the flip-flop circuit 24. During refueling, the process returns from step S14 to step S2. Note that a microcomputer can be used as the control device 20.

This recycle is repeated, for example, every 30 seconds.

As described above, according to the present invention, since a control device is provided that closes the valve based on the water detection signal from the water flow detection means, when water flows into the underground tank due to cracks or breakage of piping caused by vibration, the control device closes the valve immediately. The valve can be closed to prevent water from entering. Therefore, in the past, inspections were performed at most once every week, and oiling and refueling operations were carried out without knowing that water was flowing in.
By implementing the present invention, abnormalities can be immediately prevented.

In carrying out the present invention, the alarm may be installed at a security company or at the home of the owner of the gas station, which is located far from the gas station, and if the alarm is activated in this way, an abnormality can be immediately known after the store is closed for the night.

[Brief explanation of drawings]

FIG. 1 is a side view of a gas station implementing the water nourishment invention, FIG. 2 is a block diagram showing an embodiment of the invention, and FIG. 3 is a flowchart 1- showing an embodiment of the invention. SW1...Oil filler switch SW2...
・Nozzle switch 2.4.6...Piping 9...
・Liquid level detector 20...control device Vl, V2
, V3... Valve Figure 1 Figure 2

Claims (1)

[Claims] A valve is installed in the middle of the pipe connected to the ground tank,
An underground tank for a gas filling station, characterized in that the valve is closed by a water detection signal from a water inflow detection means installed in the underground tank.