JPS5842923A - Liquid level sensor device of oil feeding device - Google Patents

Abstract

PURPOSE:To prevent a danger in oil feeding operation, by providing a discriminating circuit which detects the output of a liquid level sensor before the oil feeding operation and then confirms normalcy. CONSTITUTION:Once a feed oil nozzle 5 is taken off from a nozzle hook, a sensor circuit 21 starts operation. Its output is supplied to a liquid level sensor 6 provided at the top of the feed oil nozzle 5, so the sensor 6 generates a prescribed pulse signal. This pulse signal is supplied to a discriminating circuit 22 through the sensor circuit 21. At this time, if the sensor 6 has a fault, the prescribed pulse signal is not inputted to the discriminating circuit 22, so it is judged that the sensor 6 is broken down, thereby putting an alarm 12 in operation. Thus, a check as to whether the liquid level sensor is out of order or not is executed in every oil feeding operation, and oil never overflows during the oil feeding operation. Therefore, a danger of the oil feeding operation is prevented.

Description

[Detailed description of the invention] The present invention relates to a liquid level sensor device for liquid supply@pupil.

For example, a refueling system W like a gas station! (Put it down,
The fuel nozzle is provided with a liquid level sensor to detect when the tank to be filled with oil is so-called "full". However, in the prior art, there is no device to check whether the liquid level sensor operates normally or not, so there is a drawback that oil overflows when the liquid level sensor is malfunctioning.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a liquid level sensor device for a liquid supply device, such as a liquid level sensor device for a fuel supply device, which can check for failure of the liquid level sensor before refueling the oil supply device.

According to the present invention, a rechargeable liquid level sensor is used. A light emitting diode that constitutes a light emitting element is blinked by an oscillator and emits a light pulse signal, and this light pulse signal is sent to a phototransistor that is a light receiving element. By providing the oscillator in this way, the light receiving element can obtain three types of signals. The three types of signals are a pulse signal that indicates that there is no liquid and that it is operating normally in the air, and a low signal that occurs when the switch is turned on when there is liquid or bubbles caused by the liquid. be.

Therefore, if a pulse signal is generated from the light receiving element before the feeding operation, it is known that the liquid level sensor is normal.

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

FIG. 1 shows an oil supply system embodying the present invention, in which oil is sucked up from an underground tank (not shown) via a suction pipe R by a pump 2 driven by a motor 1, and then discharged from the pump 2. Oil is supplied to the oil supply nozzle 5 through the II gauge 3 and the control valve 4. A liquid level sensor 6, which will be described later, is provided near the tip of the refueling nozzle 5, and a hand switch 7 is provided at the back of the refueling nozzle. The refueling nozzle 5 is hung on a nozzle hook 9, and when the refueling nozzle 5 is removed from the nozzle hook 9 for refueling, the nozzle switch sw is activated. Liquid level sensor 6
The signal from the switch and the on/off signal of the hand switch 7 are on line
1 to the control device 10. This control device 1
0 receives a signal from the nozzle switch SW via line L2. Further, the flow meter 3 converts the flow rate into a pulse signal by the pulse transmitter 3a, and the pulse signal is sent to the control device 10 by sending the line L3 to "1".
sent to. The pulse signal from this pulse transmitter, 38°, is sent from the control device jlO to the display meter 11 via line L4.
Refueling is displayed. The control device 10 controls the valve 4 via a line L5 and also controls the motor 1 via a line L6, as will be described later. Further, the control device W110 sends a signal to the alarm 12 via the line L1 as described later,
It is set to issue a warning.

Next, a specific example of the control device 10 implementing the present invention and its operation will be described with reference to FIGS. 2 and 3.

When the refueling nozzle 5 is removed from the nozzle hook 9, a signal is input from the nozzle switch SW to the sensor circuit 21, and the j sensor circuit 21 starts operating. The liquid level sensor 6 is composed of a light emitting diode 6a and a phototransistor 6b as described later, and when a pulse signal as shown in FIG. 3(a) is inputted from the oscillator 30 of the sensor circuit 21 as described later,
If there is no liquid at the liquid level sensor 6 and there is only air, an inverted pulse signal will be sent as shown in Figure 3 (B), and if there is liquid or bubbles, the point shown in Figure 3 ("li>") will be sent. When the hand switch 7 is turned on, a high-level signal 1-1t'' shown after point X is generated, and a low-level signal LO shown after point Y in FIG. 3(d) is generated.

When the liquid level sensor 6 is off, there is only air at the liquid level sensor 6, so the pulse signal shown in FIG. 3(b) is transmitted from the sensor circuit 21 to the discrimination circuit 22. When the bus/Lz signal shown in FIG. 3 (b) is transmitted to the discrimination circuit 22, the discrimination circuit 22
determines that the liquid level sensor 6 is not malfunctioning, and the counting circuit 23 erases the previous oil supply amount stored in memory according to the signal from the discrimination circuit 22. Therefore, the display meter 11 returns to zero, and the motor control circuit A motor ON signal is input to 24 to drive the motor 1, and a valve opening signal is input to the valve control circuit 25 to open the valve 4. There, the operator opens the nozzle pulp and performs the refueling operation. During the refueling operation, the pulse transmitter 3a converts the refueling signal into a pulse signal, which is counted by the counting circuit 23, and the amount of refueling is displayed on the display meter 11.

When the tank is "full" or close to "full", the liquid level sensor 6
detects oil or its bubbles or droplets. The conclusion, Figure 3 (
As shown in c), a high level signal @H1 is transmitted from the sensor circuit 21 to the discrimination circuit 22.

The discrimination circuit 22 discriminates this high level signal 1-1i,
The discrimination circuit 22 issues a valve close signal to the valve control circuit 25 and also issues a motor stop signal to the motor control circuit 24, so that the valve 47A is closed and the motor 1 is then stopped.

When the operator hooks the refueling nozzle 5 to the nozzle hook 9, the sensor circuit 21 stops its operation in response to a signal from the nozzle switch SW.

The following F is a case where the liquid level sensor 6 is operating normally.

However, if the liquid level sensor 6 is out of order, whether the cause is on the light emitting element side, the light receiving element side, or the sensor circuit, the signal sent from the sensor circuit 21 to the discrimination circuit 22 is This is a signal other than the pulse signal shown in . Therefore, if a signal other than the pulse signal shown in FIG. 3 (b) is applied to the discrimination circuit 22 when the refueling nozzle 5 is removed, the discrimination circuit 22 will notify the alarm 12 that the liquid level sensor 6 is malfunctioning. emits a signal indicating the Therefore, it can be seen that the liquid level sensor 6 is malfunctioning.

When the hand switch 7 is turned on, it sends a low level signal LO to the discrimination circuit 22. This signal LO may be used as a reset signal to the counting circuit 23, for example, when it is desired to continuously refuel the next car without operating the nozzle switch SW, that is, without applying the refueling nozzle 5 to the nozzle hook 9. , or in the case of a hanging type refueling device, it can be used as various signals such as 4 signals on the hose. Although the above description has been made assuming that the valve 4 is controlled, the present invention can be practiced even if the pump 2 is controlled without providing the valve 4.

Next, one embodiment of the sensor circuit 21 will be described with reference to FIG.

In the illustrated embodiment, the liquid level sensor 6 is a light emitting diode 6.
It consists of a, 7 ototransis, and 6b.

For example, a +5V bus line B is connected to the emitter of a transistor Tr, and an oscillator 30 is connected to the base of the transistor Tr.

This oscillator 30 emits the pulse signal shown in FIG. 3(A), and the pulse signal shown in FIG. 3(A) is generated at the collector of the query transistor Vr. This pulse signal is applied to the light emitting diode 6a through the resistor R1 and the known explosion-proof barrier circuit 31, and the light emitting diode 6a emits a light pulse signal similar to that shown in FIG. The cathode side of the light emitting diode 6a is grounded E.The intrinsically safe explosion-proof barrier circuit 31
is a well-known circuit including a fuse F, a resistor R1, and a Zener diode 2, so its explanation will be omitted.

The collector of the phototransistor 6b is connected to the bus line B via the resistor R2 and the intrinsically safe explosion-proof barrier circuit 31, and the emitter is grounded E.

Now, one input terminal of the comparator 32 for shaping the pulse signal into a rectangular wave is connected to the line between the resistor R2 and the phototransistor 6b, and the other input terminal T
2 is a resistor R connected in series between bus B and earth E.
3 and R4. These resistors R3 and R4
have the same resistance value, and a voltage of 2.5 V, which is half the voltage of the bus B, is applied to the terminal T2.

When the light from the light emitting diode 6a reaches the phototransistor 6b as indicated by the arrow a, the phototransistor 6b becomes conductive, so the voltage at the terminal 1 becomes 2.5V or less. Also, if the phototransistor 6b does not receive light or the amount of light it receives is reduced due to oil or bubbles, the phototransistor 6b will not conduct, so the voltage at the terminal T1 will be ^^
It becomes. The voltage at terminal T1 is therefore inverse to the signal of oscillator 30. In response to this voltage change, the computer sends a rectangular wave pulse signal T3 as shown in FIG. 3 to the discrimination circuit 22. The hand switch 7 is a phototransitor 6b
Therefore, when the hand switch 7 is turned on, the terminal T1 is grounded. Therefore, a low level signal 1o is issued from the comparator.

Next, an embodiment of the liquid level sensor 6 will be described with reference to FIG. 5 and FIG. 1116. The liquid level sensor 6 is connected to the liquid supply nozzle 5
It is provided at the tip of the discharge pipe 35.

FIG. 6 shows an enlarged view of the liquid level sensor 6 seen from the tip.

The liquid level sensor 6 includes a light emitting section 6a (light emitting diode) and a light receiving section 6.
bC phototransistor), each with a lens on the front. In the case of a light emitting part, this lens is made so that the light emitted from the light emitting part 6a passes through the lens 68' and then when it exits into the air, it is refracted and exits as parallel rays. On the other hand, parallel light rays are refracted by the lens 6b= and illuminated by the light receiving section 6bk: *.

Therefore, when the liquid level sensor 6 is in the air, all the light emitted from the light emitting part 6a is transmitted to the light receiving part 6b, as shown in FIG.
It reaches and outputs electrically.

When the liquid level sensor 6 is in the liquid, the light emitted from the light emitting part 6a is not only blocked by the liquid's own light passage resistance, but also the refraction angle of the lens is changed by the liquid, as shown in Figure 18 (b). Therefore, the light is scattered in a direction different from that of the light receiving section 6b, and only a very small amount of light is received. Therefore, the electrical output of the light receiving section 6b becomes almost zero. As a result, the conditions in the air and in the liquid can be determined electrically, as described above.

As described above (゛, since the embodiment shown in Fig. 4 uses pulse signals, the three types of signals shown in Fig. #13 (b), (c), and (d) are obtained. Therefore, the light receiving element When determining whether or not the light is received, it may be due to a failure of the light receiving element.
When the refueling nozzle 5 is removed, the light emitting device acts as if it has arrived and is judged to be normal, and even though the light emitting element is also malfunctioning, it is judged to be normal.When the refueling nozzle 5 is removed, ) is determined to be normal as long as the pulse signal shown in ) is present, and otherwise it is determined to be a failure, so the determination of failure is certain.

As described above, a discrimination circuit is provided to detect the output from the liquid level sensor and confirm that it is normal before the liquid supply operation, and the liquid supply operation is performed based on the signal from the discrimination circuit, so each liquid supply operation Check if the liquid level sensor is malfunctioning.
This prevents oil from overflowing during fluid supply work. Therefore, it is useful for preventing danger during liquid supply work.

[Brief explanation of the drawing]

Claims (1)

[Claims] Liquid supply 4 controlled by the signal from the liquid level sensor! In C, the liquid supply device is characterized in that a discrimination circuit is provided to detect the output from the liquid level sensor and confirm that it is normal before refueling operation, and the liquid supply operation is performed according to a signal from the discrimination circuit. Liquid level sensor device.