JPH0651515B2 - Overfilling prevention device for underground tank - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention compares the liquid level of an underground tank with a set value when unloading gasoline or the like from a tank truck to an underground tank such as a gas station. Detects the full volume,
The present invention relates to a device that prevents an amount of lubrication that exceeds a preset amount of lubrication, that is, supercharging.

[Conventional technology]

In gas stations and the like, it is widely practiced to bury a tank for storing gasoline, kerosene, etc. in the basement of the site.

When refueling such an underground tank with gasoline or the like, a tank truck is driven near the refueling hose connection port, and the tip of the refueling hose is attached to the refueling hose connection port for refueling.

Conventionally, this refueling work has been performed while visually confirming the amount of storage in each underground tank with a fuel gauge or a measuring stick installed in each underground tank of a gas station.

If this visual check is incorrect, gasoline may overflow from the tank.

Due to this overflow, not only is gasoline wasted, but there is a risk of ignition and a fire or explosion,
If spilled into public sewers or rivers, there is a risk of pollution and disaster.

As a means for preventing this overflow, for example, there is a means disclosed in Japanese Patent Publication No. 60-35612 by the present inventor, which is connected to a liquid level indicator with a full oil alarm device to prevent excessive oil supply.

This alarm device is provided with a liquid level sensor having a transmitting function in the tank and digitally displays the signal from this liquid level sensor. The upper limit display is connected to an alarm device to alert the superlubrication buzzer. And so on.

Then, with this alarm, the worker closes the fueling valve of the tank truck to prevent over-fueling.

In this way, the operation of this refueling valve is performed after the operator confirms the alarm, so as if the operator activated the alarm when he was away from the site, he did not notice the alarm or operated the valve. If the closing timing is delayed, overflow may occur.

In order to deal with the problem caused by the mistaken confirmation of the alarm, as shown in Japanese Patent Laid-Open No. 53-43221, a mechanism for detecting an overflow is used as an overflow prevention mechanism when lubricating a bunker oil dedicated vessel to a ship. It is also conceivable to adopt a system in which the overflowed amount is sent to another route by combining with the float switch.

However, when applying such equipment to an underground tank and installing it, it is necessary to construct an overflow oil passage in addition to the supply pipe and adjust the level of each tank. Not practical and recruitment is difficult as a practical matter.

[Problems to be Solved by the Invention]

An object of the present invention is to fundamentally solve the above-mentioned problem of overflow of supply oil in an underground tank, and to provide a super-lubrication prevention device that accurately and reliably controls a set supply amount. It is in.

[Means for Solving the Problems]

The present invention stores liquid level detectors for detecting the liquid level in each of a plurality of underground tanks, stores a preset planned refueling level, and compares the difference between the planned level and the liquid level detector. In an over-refueling prevention device for an underground tank of a refueling facility equipped with a liquid amount management device for calculating and managing, the liquid amount management device is a full liquid amount preset in a tank selected arbitrarily in each underground tank. And a liquid level detected by the liquid level detector, and when the liquid level reaches a predetermined full liquid level, a comparison means is provided for generating an electric signal, and from this comparison means Is provided with a valve that operates in response to the output signal of 1 to open and close the oil passage of the oil supply pipe that connects the ground oil supply hose connection port and the underground tank.

By using an air valve as the valve, safer and more reliable operation becomes possible.

[Action]

When the liquid level in the underground tank reaches a preset full liquid level, the preset liquid level in the underground tank is compared with the liquid level detected by the liquid level detector to determine that the liquid level is full. When the liquid amount is reached, the valve automatically closes and the refueling is stopped by the signal emitted from the comparison means.

〔Example〕

Hereinafter, the present invention will be specifically described based on the embodiments shown in the drawings.

FIG. 1 is a schematic diagram showing the configuration of an embodiment of the present invention. In this embodiment, three horizontal cylindrical underground tanks
10, 20, 30 are buried underground. FIG. 2 shows the cross section. The underground tanks 10, 20, 30 are provided with liquid level detectors 11, 21, 31 for detecting the liquid level of floats, etc., and in addition to these, fuel filler ports 12, 22, 32, vent holes 1
3, 23, 33, a suction pipe 19 for sending oil to a weighing stand installed on the ground is provided. Refueling port 12, 22,
Refueling pipes 15, 25, 35 are provided between the 23 and the refueling hose connection ports 14, 24, 34 on the ground, and air valves 16, 26, 36 are installed in the middle thereof.

As shown in FIG. 1, the liquid level signals detected by the liquid level detectors 11, 21, and 31 are input to the liquid amount management device 1. In the liquid volume management device 1, the liquid volume is calculated based on the liquid level signal and the sectional shape of the underground tanks 10, 20, 30 and displayed on the liquid volume display 2. On the other hand, the liquid volume management device 1
In the above, the value at which the valve operates depending on the full volume of the underground tank 10, 20, 30 is set in advance, and it is configured so that any of the relays 17, 27, 37 of the specific underground tank can be operated. Any of 17, 27, 37 works,
It is configured to open the corresponding solenoid valve 18, 28, 38. Then, when the specific relay is activated, the other relays are not activated.

When the liquid level in the operating underground tank reaches the full level, each solenoid valve 1
8, 28, 38 are the compressor 3 and the air valves 16, 2
6 and 36 to control the air flow path, and when the solenoid valve 18, 28 or 38 opens, the corresponding air valve 16, 2
Close 6,36. When the air valve 16, 26 or 36 is closed, the refueling hose connection port 14, 24, 34 and the underground tank 10, 20,
Since the refueling pipes 15, 25, and 35 with 30 are closed, it is no longer possible to refuel from the tank truck. At the same time, an alarm is issued to alert the worker.

In this way, refueling is automatically stopped when the underground tank is filled with oil, and it is possible to prevent overfilling as well as overflow.

FIG. 3 is a block diagram showing a configuration example of the liquid quantity management device 1. In this example, the electric system for the liquid level detector 11 of the underground tank 10 is shown, but other tanks have the same circuit configuration.

In FIG. 3, the signal from the liquid level detector 11 is the Zener barrier 7
Sent to. The Zener barrier 7 is a power supply provided with an explosion-proof measure by using a Zener diode to limit the output current and voltage. The signal input to the Zener barrier 7 is sent to the liquid level gauge 2 to display the liquid level, and is also sent to the comparison circuit 4 to be compared with the set voltage of the full liquid level setting device 5. When the liquid level reaches the full level, the output of the comparison circuit 4 is inverted and the signal is output to the relay 17 via the photocoupler 6 to operate the solenoid valve 18. SW1 is an automatic / manual switch, and SW2 is a manual open / close switch.

Although FIG. 3 shows an example in which the liquid volume control device 1 is configured by an analog circuit, it may be a digital circuit.

FIG. 4 shows an example of a digital circuit. In this example, the Zener barrier 7 is the same as the example of FIG. 3, but
The output of the level adjusting circuit 4 for adjusting the voltage signal level from the sensor 11 is converted from analog to digital through the A / D converter 41, and the CPU 42 inputs the digital signal corresponding to this oil level. . Compare this signal with the full oil set level stored in the memory 43,
When they match, the air valve close and buzzer on signals are output to the input / output interface. These signals are output to the relay 17 (solid state relay) via the photocoupler 6 to operate the solenoid valve 18. When the oil level in the tank drops and falls below the full oil level, the air valve open and buzzer off signals are output. Further, by connecting a setting device separately, the full oil level can be arbitrarily changed at the site, and the same oil type can be subdivided into each tank for oiling.

〔The invention's effect〕

 The present invention has the following effects.

(1) A comparison means is provided in the liquid amount management device provided to measure the liquid level of the underground tank, and the preset supply amount of the underground tank and the liquid level detected by the liquid level detector are set. When the liquid level reaches the planned amount, the signal from the comparison means is used to close the valve and stop refueling. Since it surely stops, accidents due to overflow can be completely prevented.

(2) Before starting unloading, the procedure is to select the relevant tank and open the valve to unload the tank. Even if the tank is mistakenly started to be lubricated, the valve will not close and lubrication will not be performed. Therefore, it is possible to prevent a mixed oil accident.

(3) Since no pressure is applied to the tank during operation, the filled gas does not burst and the operation is safe.

(4) Before starting unloading and refueling from the lorry,
If you select the corresponding tank, open the valve, and unload the tank, even if you start oiling by mistake in the tank, the valve will be closed and the oil will not be added.

(5) By using an air valve as a direct valve for stopping the replenishment of oil, it is possible to prevent ignition due to sparks due to an accident in the electrical system, which is safe.

(6) It is easy to install and can be easily installed on an existing tank.

[Brief description of drawings]

FIG. 1 is an electrical system diagram showing an embodiment of the present invention, FIG. 2 is a sectional view of an underground tank, FIG. 3 is a block diagram showing a configuration example of a liquid volume management device, and FIG. 4 is a liquid volume management device. It is a block diagram showing an example in the case of being constituted digitally. 1: Liquid amount management device, 2: Display device 3: Compressor, 4: Comparison circuit 5: Liquid level setting device, 6: Photo coupler 7: Zener barrier 10,20,30: Underground tank 11,21,31: Liquid level Detector 12,22,32: Refueling port 13,23,33: Vent 14,24,34: Refueling hose connection 15,25,35: Refueling piping 16,26,36: Air valve 17,27,37: Relays 18, 28, 38: Solenoid valve 19: Suction pipe 41: A / D converter 42: CPU 43: Memory 44: Output interface

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-53-43221 (JP, A) JP-B 59-34596 (JP, B2) JP-B-49-23302 (JP, Y1) JP-B-48- 5385 (JP, Y1)

Claims (2)

[Claims] 1. A liquid level detector for detecting a liquid level in each of a plurality of underground tanks and a preset planned refueling level are stored, and a difference between the planned level and the liquid level detector is determined. In an overfill prevention device for an underground tank of a refueling facility equipped with a liquid amount management device for comparative calculation management, the liquid amount management device is a full liquid preset in a tank selected arbitrarily in each underground tank. And a comparing means for generating an electric signal when the liquid level detected by the liquid level detector reaches a predetermined full liquid level by comparing the liquid level with the liquid level detected by the liquid level detector. A device for preventing excessive refueling of an underground tank, which is equipped with a valve that operates in response to an output signal from the oil tank to open and close an oil passage of an oil supply pipe that connects a ground hose connection port and an underground tank. 2. A device for preventing excessive oil supply to an underground tank according to claim 1, wherein the valve is an air valve.