JPH0735596A - Measuring device for residual oil quantity in underground tank - Google Patents

Abstract

PURPOSE:To transmit accurate information about and reliable residual quantity of fuel oil in an underground tank and its related matters without being affected by noise. CONSTITUTION:A receiving portion 16 is provided in the riser 15 of a ventilation pipe 5 extending from an underground tank 1 placed underground in a gas station. The remaining oil quantity within an underground tank 1, detected by a potentiometer 7, is transmitted with sound wave or electromagnetic wave, and received by the receiving portion 16, and displayed on a display picture.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for measuring the amount of residual fuel oil in an underground tank buried underground such as a gas station.

[0002]

2. Description of the Related Art Generally, gasoline,
A plurality of underground tanks in which fuel oil such as light oil and kerosene is stored for each oil type are buried, and the residual oil amount of the fuel oil in each underground tank is, for example, Japanese Utility Model Publication No. 61-205027 (Practical application). It is detected and displayed by a residual oil amount measuring device as shown in JP-A-61-89639).

In this prior art, a residual oil amount detecting means for detecting the residual oil amount is provided in an underground tank buried underground,
The residual oil amount detected by the residual oil amount detecting means is transmitted as an electromagnetic wave, received by the receiving means provided in the management room of the gas station, and displayed by the display means.

In such a prior art, when a tank truck for lubricating the underground tank is stopped or there is a lot of snow on the road surface directly above the underground tank, noise is generated in the radio waves transmitted from the transmitting means. There is a problem that the residual oil amount in the underground tank and the like cannot be accurately and reliably displayed by the display means because of the possibility of mixing in or damaging the radio wave propagation.

In order to solve such a problem, in another prior art, in order to transmit the information such as the amount of residual oil from the transmitting means to the receiving means, a signal line is buried under the ground of a gas station. Wired type connected to the receiving means is well known, but in this prior art, since the signal line must be buried, after crushing the concrete roadbed, excavation is performed to a depth to fill the signal line. Therefore, it is necessary to lay a signal line and bury the excavated earth and sand again to pour concrete, which is very troublesome for laying the signal line.

[0006]

SUMMARY OF THE INVENTION Therefore, the object of the present invention can be easily implemented with a simple structure, and the signal transmitted from the transmitting means can be transmitted without noise and is accurate and reliable. Another object of the present invention is to provide a residual oil amount measuring device for an underground tank which can be received by the receiving means.

[0007]

According to the present invention, fuel oil is stored in an underground tank buried underground, and a ventilation pipe communicating with the internal space of the underground tank and the atmosphere is connected to the upper portion of this underground tank. The gas phase in the underground tank is opened to the atmosphere through the ventilation pipe, and the underground tank has residual oil amount detecting means for detecting the residual oil amount of the fuel oil stored in the underground tank. In an underground tank residual oil amount measuring device provided on the ground with display means for displaying the residual oil amount based on the output from the residual oil amount detecting means, the residual oil amount detecting device is provided in the underground tank to detect the residual oil amount. Transmitting means for converting the output from the means into sound waves or electromagnetic waves and transmitting in the underground tank,
It is provided in the rising part rising from the ground of the ventilation pipe,
A residual oil amount measuring device for an underground tank, comprising: a receiving unit that receives a sound wave or an electromagnetic wave transmitted from the transmitting unit, converts it into an electric signal, and transmits the electric signal to the display unit.

[0008]

According to the present invention, the residual oil amount in the underground tank is detected by the residual oil amount detecting means, and the output from the residual oil amount detecting means is converted into a sound wave or an electromagnetic wave by the transmitting means and is converted in the underground tank. The transmitted sound wave or electromagnetic wave is received by the receiving means provided in the ventilation pipe and displayed by the display means. In this way, the information detected by the residual oil amount detecting means can be converted into sound waves or electromagnetic waves and transmitted by using the ventilation pipe communicating with the underground tank, so that it is possible to avoid the influence of disturbance such as noise. The amount can be significantly reduced, the amount of residual oil and its related information can be transmitted accurately and reliably, and it can be laid without major construction such as crushing the roadbed.

[0009]

1 is a simplified sectional view showing a residual oil amount measuring device 2 for an underground tank 1 according to an embodiment of the present invention. An underground steel tank 1 made of steel is buried under the fueling station, and a steel ventilation pipe 5 rising upward from a concrete roadbed 4 is connected to an upper portion 3 of the underground tank 1. Fuel oil 6 such as gasoline, light oil, and kerosene is stored in the underground tank 1.
Is stored, and the residual oil amount is detected by the potentiometer 7 which is a residual oil amount detecting means. The potentiometer 7 has a float 9 floating on the oil surface 8 of the fuel oil 6, and detects the amount of vertical displacement of the float 9.
Such a potentiometer is, for example, a CP (Conducer
A tive plastic (conductive plastic) type linear potentiometer is preferably used. An optical potentiometer or a magnetic linear potentiometer may be used instead of the CP linear potentiometer.

Such a potentiometer 7 is provided in the housing of the transmitter 10, and the transmitter 10 is housed in an iron monitoring box 11 buried under the ground.
It is supported on an end plate 13 that closes the manhole 12 of the underground tank 1 protruding into the monitoring box 11.

In the underground tank 1, a gas phase 14 filled with a mixed gas of the vapor of the fuel oil 6 and air is present on the oil surface 8 of the fuel oil 6, and the gas phase 14 is the above-mentioned gas passage. It is opened to the atmosphere via the trachea 5. A receiving portion 16 is provided at a rising portion 15 of the ventilation pipe 5 rising to the ground, and the receiving portion 16 is provided.
A sound wave signal indicating the amount of residual oil emitted from the transmission means 20 of 0 and its related information such as temperature is received and displayed on the display screen 19 of the display means 18 of the monitoring device 17 provided in the control room of the gas station, for example. Digitally displayed. Such display means 18 is realized by, for example, a cathode ray tube (abbreviated as CRT).

FIG. 2 is a simplified block diagram for explaining a specific configuration of the transmission section 10. When the oil level 8 in the underground tank 1 is displaced, the float 9 is vertically displaced according to the displacement of the oil level, and the oscillation frequency of the measuring circuit 21 is changed by the change in the resistance value of the potentiometer 7,
The output is processed into a digital value by a signal processing circuit 22 realized by a CPU (central processing unit) or the like, and then converted into an analog value by a modulation / transmission circuit 23, as shown in FIG. It is modulated and amplified, and as shown in FIG. 3 (2), the high frequency f1 and the low frequency f2 are alternately repeated to generate an acoustic signal such as a "peepo" from the speaker 24.

Electric power is supplied to the measuring circuit 21, the signal processing circuit 22 and the modulation / transmission circuit 23 from a battery 26 as a backup power source. The acoustic signal emitted from the speaker 24 can be transmitted by a method similar to that of an acoustic coupler, which is a device for transmitting data using a public telephone line, for example, from the signal processing circuit 22 to a modulation / transmission circuit. The signal supplied to 23 is
As shown in FIG. 3A, the high level “1” is set to f1 =
1270 Hz, low level "0" f2 = 1070
You may make it transmit as a sound of Hz. The transmission rate at this time may be, for example, 300 baud.

The acoustic signal generated from the speaker 24 as described above has a period W = 1 sec as shown in FIG.
Alternatively, the oil temperature information and the battery voltage information may be transmitted only immediately after the start of work at the gas station. Such oil temperature information is detected by a temperature sensor (not shown) provided on the float 9. The voltage value itself is converted into a signal for the battery voltage information.

FIG. 5 is a simplified block diagram for explaining a specific configuration of the receiving section 16. The receiving unit 16 provided at the rising portion 15 of the ventilation pipe 5 has a microphone 27 provided so as to face the inside of the ventilation pipe 5. The acoustic signal received by the microphone 27 is filtered by a filter 28 to remove noise, and an amplifier circuit is provided. After being amplified by 29, it is demodulated into a digital signal by the demodulation circuit 30, and each value of liquid level, oil temperature and battery voltage is output to the monitoring device 17 as an electric signal to be displayed by the display means 18 and the battery is exhausted. When the voltage drops below a certain value, this is notified and the battery replacement is prompted.

In this way, the speaker 24 of the transmitter 10 is
The residual oil amount and its related information emitted from the converter is converted into an acoustic signal and received by the receiving unit 16 via the ventilation pipe 5 without being affected by noise, and is displayed by the display means 18 of the monitoring device 17. Can be displayed. Therefore, even if the tank truck stops right above the transmission unit 10 or there is a lot of snow, the remaining oil amount and its related information can be accurately and reliably transmitted to the monitoring device 17. Moreover, since the transmitter 10 and the receiver 16 can be attached to the existing underground tank 1 and the ventilation pipe 5 without major modification, the present invention can be widely applied in connection with the existing gas station facilities. You can

In the above-described embodiment, the residual oil amount and its related information are transmitted from the transmitting section 10 by sound waves, but as another embodiment of the present invention, the residual oil amount and its related information are transmitted by electromagnetic waves. You may make it transmit.

Further, in the above-mentioned embodiment, although the FM modulation system in which the oscillation frequency is changed according to the change of the resistance value of the potentiometer 7 is used, other modulation system, for example, amplitude modulation system may be used. .

Further, in the above-mentioned embodiment, the potentiometer 7 is used as the residual oil amount detecting means, but as another embodiment of the present invention, an optical distance sensor, an ultrasonic distance sensor, an electrostatic distance sensor. Also, a digital linear distance sensor such as a magnetic distance sensor may be used, or an electromagnetic induction type distance sensor or an ultrasonic distance sensor may be used as an analog type.

Further, the microphone 27 may be arranged not to face the rising pipe 15 directly but to face the atmosphere opening hole provided at the tip of the ventilation pipe 5.

[0021]

As described above, according to the present invention, the residual oil amount of the fuel oil in the underground tank and its related information are converted into sound waves or electromagnetic waves and transmitted, and received by the receiving means provided in the ventilation pipe. As a result, even when there is a tank truck or a lot of snow cover on the underground tank, the residual oil amount and its related information can be transmitted accurately and reliably. In addition, the residual oil amount and its related information are converted into sound waves or electromagnetic waves to be transmitted in the underground tank and received by the receiving means via the ventilation pipe, so that noise from the outside is less mixed and radio wave interference occurs. There is no fear of being affected by the above, and this also enables accurate and reliable transmission of the residual oil amount and its related information.

[Brief description of drawings]

FIG. 1 is a simplified cross-sectional view showing a residual oil amount measuring device 2 for an underground tank 1 according to an embodiment of the present invention.

FIG. 2 is a simplified block diagram for explaining a specific configuration of a transmitter 10.

FIG. 3 is a waveform diagram showing a signal input to a modulation / transmission circuit 23 of a transmission unit 10 and an acoustic signal transmitted from a speaker 24.

FIG. 4 is a diagram showing an acoustic signal generated from a speaker 24.

FIG. 5 is a simplified cross-sectional view showing a specific configuration of the receiving unit 16.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Underground tank 2 Residual oil amount measuring device 3 Upper part 5 Vent pipe 6 Fuel oil 7 Potentiometer 10 Transmission part 14 Gas phase 15 Rising part 16 Receiving part 17 Monitoring device 18 Display means 24 Speaker 27 Microphone

Claims (1)

[Claims] 1. A fuel oil is stored in an underground tank buried underground, and a ventilation pipe communicating with the internal space of the underground tank and the atmosphere is connected to the upper portion of the underground tank, and the ventilation pipe is connected via this ventilation pipe. The gas phase in the underground tank is opened to the atmosphere, and the underground tank is provided with residual oil amount detecting means for detecting the residual oil amount of the fuel oil stored in the underground tank, and the residual oil is provided on the ground. In a residual oil amount measuring device for an underground tank provided with display means for displaying the residual oil amount based on the output from the amount detecting means, the output from the residual oil amount detecting means is provided in the underground tank, and the output from the residual oil amount detecting means is a sound wave or an electromagnetic wave. Transmitting means for converting to and transmitting in the underground tank, and provided in the rising portion rising from the ground of the ventilation pipe,
A residual oil amount measuring device for an underground tank, comprising: a receiving unit that receives a sound wave or an electromagnetic wave transmitted from the transmitting unit, converts it into an electric signal, and transmits the electric signal to the display unit.