JPH02264826A - Detecting apparatus for residual oil amount in oil tank - Google Patents

Abstract

PURPOSE:To improve the detecting accuracy and to simplify the structure of a detecting apparatus by moving a flat electrode in accordance with the amount of the residual oil thereby to change the capacity and the frequency of an oscillating circuit. CONSTITUTION:A lever 14 having a fulcrum 12 at one side and a flat electrode 18 at the other side is placed on a base 11. An oil tray 15 and an oil tank 16 are placed on the lever 14. A spring mechanism 20 and a flat electrode 13 confronting to the electrode 18 are provided between the lever 14 and base 11. Moreover, an oscillating circuit having the capacitors of the electrodes 13, 18 as one factor is formed. Thus, the change of the weight of the oil tank 16 and oil tray 15 is converted to the moving distance which distance is converted to the change of the capacitance by the flat electrodes 13, 18. Then, the change of the capacitance is converted to an oscillating frequency by the oscillating circuit. The oscillating frequency is read by a microcomputer and displayed by a display part.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for detecting the amount of residual oil in an oil tank of a hot air heater.

Conventional technology Conventionally, a device that detects the amount of remaining oil in an oil tank or in an oil tank and an oil pan, receives it as an input signal to a control device, and further displays the amount of remaining oil as an output of the control device is disclosed in the Japanese Patent Publication No. 62.
Seen in Japanese Patent No.-33488. To explain this remaining oil amount detection device with reference to FIG. , the rack 4 attached to the oil tank 1 changes to the upper and lower positions by the downward movement.

This is converted into a change in the rotation of the gear 5. This rotation is converted into a resistance change of a variable resistor, further converted into voltage, A/D converted, and applied to the input port of the microcontroller, and processed by the microcontroller.
The display section was driven by signals from a microcomputer.

Problems to be Solved by the Invention The conventional residual oil amount detection device is configured as described above.
The travel distance from when the oil tank is full until it becomes empty is about 1 to 31101 degrees. The weight change is only about 1kg compared to about 6kg. Therefore, a considerable amount of force is required to compensate for the change in the rotation of the gear 5 due to the change in the upper and lower positions of the rack 4 and rotate the variable resistor, but in the conventional example described above, since the force is small, the rotation angle is small. The disadvantages are that the detection accuracy is poor and the structure is complicated.

Means for solving the problem: A lever with a fulcrum on one side and a flat electrode on the other is placed on a stand, an oil pan and an oil tank are placed on the lever, and a spring mechanism and another flat plate are placed between the lever and the stand. An oscillation circuit is constructed in which electrodes are provided and the capacitors of the two-handed plate electrodes are used as one element.
This is connected to a microcomputer, and the displacement of the gap between the flat electrodes is displayed on the microcomputer's display. In this case, a displacement of about 0.05 mm to 0.1 mm is sufficient.

The plate electrode moves depending on the amount of remaining oil, changing the capacitance and changing the frequency of the oscillation circuit. The microcontroller reads the frequency changes and controls and displays them on the display.

Example An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 11 denotes a stand, on which is installed a lever 14 having a fulcrum 12 on one side and a flat plate electrode 18 having at least one flat side on the other side. On top of the lever 14 is an oil saucer■5
．． Place oil tank 1G and pump 17 on it.

Another flat plate electrode 13 having at least one flat surface is positioned below the flat plate electrode 18 and fixed on the mounting table 11. A spring mechanism 20 is inserted between the lever 14 and the stand 11 to support the weight of the oil tank 16 and the like. In Figure 2, a flat plate electrode 13.18, a resistor 23.24,
An oscillation circuit A is configured by CMOS inverters 25 and 26.

The output of oscillation circuit A is connected to clock terminal 27 and reset terminal 2.
8. It is connected to a clock terminal 27 of a counter circuit B having an output terminal 29. The output terminal 29 of the counter circuit B is connected to the interrupt input terminal of the microcomputer 30. Microcomputer 3
0 N-Ch output port has resistors 31, 32, and 33, respectively.
. However, microcontroller 3
If the processing speed of 0 is considerably faster than the oscillation frequency of oscillation circuit A, counter circuit B is unnecessary.

40 is an output port to the counter circuit B of the microcomputer 30;
41 is an input port, 42 and 43 are output ports to the LEDs 35 to 38, and 39 is a DC power supply.

3a is a diagram showing the relationship between the gap between the flat plate electrode 13 and the flat plate electrode 18 and the amount of kerosene; FIG. FIG. 3C is a diagram showing the relationship between capacitance and oscillation frequency. Therefore, a diagram showing the relationship between the amount of kerosene and the oscillation frequency is as shown in FIG. 3d. Oscillation frequency and LE
The microcomputer 30 is programmed so that the relationship with the lighting states of D35 to D38 is as shown in FIG. 3e.

Since the present invention has the above configuration, the spring mechanism 20
are oil tank 16, oil pan 15. Balance is maintained at a certain position by the load of the pump 17 and the like. When the oil tank 16 is full of kerosene, the spring mechanism 20 receives a considerable load, and the lever 14 uses the fulcrum 12 as a fulcrum to move the mounting base 1.
It is being pushed towards 1 (downward).

As shown at point m in FIG. 3a, the gap between the flat electrode 13 and the flat electrode 18 is small. Therefore, the picture electrode 13
．． The capacitance between 18 and 18 is as shown at one point in Figure 3. Since the oscillation circuit A is oscillated by the capacitor between the picture electrodes 13 and 18 and the inverter 25.2G,
The oscillation frequency at this time is as shown at point m in FIG. 3C. Therefore, the relationship between the amount of kerosene and the oscillation frequency is as shown at point m in FIG. 3d.

Microcontroller 30 detects this oscillation frequency regardless of the amount of kerosene.
Reset terminal 2 of counter circuit B from output port 40 of
8 Give a heliset pulse. In this way, counter circuit B
is cleared to zero and starts counting the oscillation frequency of the 1 oscillation circuit A. When counter circuit B overflows, an overflow signal is output from output terminal 29. This signal is input from the interrupt input port 41 of the microcomputer 30. The microcomputer 30 measures the time from outputting a reset pulse to the reset terminal 28 of the counter circuit B from the output port 40 until receiving an overflow signal to the input port 41. Therefore, the microcomputer 30 knows the overflow time and the number of pulses of the counter circuit B, and therefore knows the oscillation frequency. Therefore, the program of microcomputer 30 (
The relationship between the oscillation frequency and the LED is shown in Figure 3 e).
35 to 38 output low level output signals from the output ports 42 to 45 of the microcomputer 30, as shown at point m in FIG. 3e. The LEDs 35 to 38 are energized via the resistors 31 to 34 and are turned on. Therefore, by looking at the lighting states of the LEDs 35 to 38, it can be seen that the oil tank 16 is full.

Next, a case where the oil tank 16 is nearly empty will be explained. When the tank is nearly empty, the force of the spring mechanism 20 pushes the lever 14 upwardly above the stand 11 using the fulcrum 12 as a fulcrum compared to when the tank is full. The gap between the flat plate electrode 13 and the flat plate electrode 18 becomes large, as shown at point n in FIG. 3a. Therefore, the capacitance between the picture electrodes 13 and 18 is small as shown at point n in FIG.

The oscillation frequency at this time becomes small as shown at point n in FIG. 3C. Therefore, the relationship between the amount of kerosene and the oscillation frequency is as shown at point n in FIG. 3d. As mentioned above, microcomputer 30
detects the oscillation frequency. Since the amount of kerosene is small, the oscillation frequency becomes small, and the microcomputer 30 performs the process at point n in FIG. 3e. A low level output signal is output from the output port 45 of the microcomputer 30.

The LED 38 is energized via the resistor 34 and lights up. Therefore, by looking at the lighting status of the LED 38, it can be seen that the oil tank 16 is almost empty.

For intermediate oil quantity, LED38.37 or LED38
．． Since 37.36 lights up, it can be seen that the oil level is at the intermediate level.

Here, if the processing speed of the microcomputer 30 is much faster than the oscillation frequency, connect the input port 41 of the microcomputer 30 directly to the output of the oscillation circuit A, and measure the time between the rise or fall of the output of the oscillation circuit A. However, the oscillation frequency may also be detected.

Effects of the Invention As described above, the present invention utilizes this principle in the oil tank and oil pan to provide a fulcrum and a spring mechanism, and further converts weight changes of the oil tank and oil pan into a moving distance. Two flat plate electrodes convert the change into capacitance, an oscillation circuit of this capacitance and resistance converts it into an oscillation frequency, and a microcomputer reads the oscillation frequency and displays it on one display, so small forces and small displacements can be generated. The output signal is large, the detection accuracy is improved, and the structure is simple.

Although the present invention uses a lever in the oil tank and the oil pan, the same effect can be obtained even if the lever is used only in the oil tank.

Furthermore, the same effect can be obtained by using an oil tank, oil pan, etc., without providing a separate lever.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a detection section of an oil tank residual oil amount detection device according to an embodiment of the present invention, and FIG. 2 is a circuit diagram thereof. FIGS. 3a, b, c, d, and e are characteristic diagrams, and FIG. 4 is an explanatory diagram of the configuration of a detection section of a conventional oil tank residual oil amount detection device. ■３...Plant electrode, 14...Lever, 16
... Oil tank, 18 ... Flat plate electrode, 20
...Spring mechanism, 30...Microcomputer, 35
．． 36.37,38...LED, A...Oscillation circuit, C...Display section.

Claims (1)

[Claims] A lever (14) having a fulcrum (12) on one side and a flat electrode (18) attached on the other is placed on the stand (11), and an oil pan (15) and an oil tank (16) are placed on the lever (14). and a spring mechanism (20) and a flat plate electrode (13) corresponding to the electrode (18) between the lever (14) and the stand (11).
is provided, and an oscillation circuit (A) including capacitors of both electrodes (13) and (18) as one element is constructed, and this oscillation circuit (
An oil tank residual oil amount detection device characterized in that A) is connected to a microcomputer (30), and displacement of both electrodes is displayed on a display section (C) of the microcomputer (30).