JPH0230736Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a liquid container such as a thermos flask or an airpot, in which the amount of liquid stored therein is measured and displayed by electrical means.

Conventional thermos flasks, airpots, etc. had the inconvenience of not being able to see the liquid content from the outside and not being able to tell the amount of liquid inside the container, so liquid containers that measure and display the amount of liquid using electrical means have been developed. However, conventional liquid containers of this type have a configuration in which electrodes are provided at different heights within the container, a voltage is applied to the electrodes, and the current flowing between the electrodes is detected to display the liquid level. , a structure in which a liquid container is provided with opposing electrodes, and by utilizing the fact that the capacitance between the opposing electrodes depends on the amount of liquid, the amount of liquid is detected from the amount of current flowing by applying an alternating current voltage between these electrodes. It was hot.

However, with the above configuration, which detects and displays the liquid amount from the current value, it is necessary to flow a large current to the extent that it can be observed, which has the disadvantage of consuming a relatively large amount of power. Highly accurate display has been impossible because the current value changes immediately when the applied voltage drops due to voltage drop, and the current depends on the concentration of impurities in the liquid and other external factors. In other words, when using dry batteries etc. as a power source,
Since the power supply voltage gradually decreases in accordance with the amount of power consumed, a drawback arises in that the battery must be replaced at an early stage in order to provide highly accurate display.

In view of these conventional drawbacks, the present applicant has proposed in a separate application that a considerable improvement can be achieved by means of measuring the amount of electricity required for charging and discharging between electrodes instead of measuring the current between opposing electrodes. Although it was disclosed,
Since the liquid volume was detected by applying a pulse voltage of a certain duration between opposing electrodes at certain time intervals and counting the number of pulses until the voltage was charged to a certain voltage, the capacitance was large. The larger the amount of liquid, the longer the time required to charge the battery, and during that time, electrophoresis of impurities in the liquid and other external factors outside the liquid container appear, making it impossible to accurately measure the amount of liquid. Problems remained.

Therefore, in order to solve this problem, it is conceivable to shorten the time required for charging by, for example, setting a large pulse voltage time width, but in this case, the amount of liquid is small and the capacitance is low. If it is small, the accuracy of the measurement result will be poor, especially when there is no remaining liquid level.The liquid level display is provided to make the user aware of this early on and to avoid situations such as insufficient liquid level. There is a risk that the objectives of the period may not be achieved.

The present invention was developed in view of the above-mentioned circumstances, and by devising the time width of the pulse voltage,
To shorten the time required for charging when the amount of liquid is large so that accurate liquid amount measurement can be performed even when the amount of liquid is large, while preventing the accuracy of measurement results from becoming rough when the amount of liquid is small. With the goal.

The characteristic structure of the liquid container according to the present invention to achieve the above object is that the capacitance increases as the amount of liquid in the container increases, and the counter electrode provided on the liquid container and the discharge period between the counter electrodes are set. A voltage application circuit that sequentially applies pulse voltages of longer duration between the opposing electrodes, and an applied pulse when the voltage between the opposing electrodes reaches a reference voltage. The present invention has a display circuit that displays the amount in stages, and this configuration provides the following effects.

In other words, since charging is performed by sequentially applying pulse voltages with long durations between opposing electrodes, even when the capacitance is large, that is, when the amount of liquid is large, compared to applying pulse voltages with a constant duration. The charging time can be shortened, and the liquid amount can be displayed accurately without being affected by the concentration of impurities contained in the liquid in the container. When the amount of liquid is low, it can be charged by applying a pulse voltage of a relatively short duration, so it is possible to measure the liquid amount with high accuracy, and to provide a highly practical liquid container that can sufficiently achieve the intended purpose of displaying the liquid amount. I've reached it.

Examples will be described below based on the drawings.

Fig. 1 shows a cross section of the airpot. 1 is the main body of the airpot, 2 is an outer lid that is connected to the main body 1 by a hinge part 3 and can be opened and closed by swinging, and 4 is a medium bottle made of a double glass bottle housed in the main body 1. , 5 is an inner stopper that is inserted into and removed from the upper opening of this inner bottle. Inside this inner stopper 5, there is a stainless steel water lift pipe 6 hanging down from the bottom surface of the inner stopper 5.
A communicating portion 8 of the water injection pipe 7 is formed to protrude forward, and a tipping water stop valve 9 is housed in the communicating portion 8 to prevent water leakage due to tipping over or the like. Also, inside this inner stopper 5, a bellows pump 10 housed in the outer cover 2 is provided.
A vent passage 12 is formed that communicates the exhaust port 10' of the bottle 4 with the inside of the medium bottle 4. This bellows pump 1
A hook valve 11 is provided on the upper surface of 0, and this hook valve 11 is biased upward by the force of a spring 14 and abuts against the push plate 13 above, and when no external force acts on the push plate 13, the hook valve 11 , the inside and outside of the bellows pump 10 are communicated, the bellows pump 10 is extended, and the push plate 13 is pushed upward. Therefore, as is well known, by pushing the push plate 13, the hook valve 11 is closed and the bellows pump 10 is compressed, and air from the bellows pump 10 is sent into the medium bottle 4 through the ventilation path 12. This pressure causes the medium bottle 4 to
The airpot of this embodiment is configured so that the liquid inside is discharged from the outlet of the water injection pipe 7 and guided to the outside through the water injection auxiliary pipe 15.

Reference numeral 16 is a liquid crystal display device provided on the front surface of the water filling cover 17 for displaying the liquid level, which has a liquid level display section 32 that displays the liquid level in seven levels and a battery display section 33 that indicates whether the battery is normal. It is an indicator. Reference numeral 18 denotes a battery storage section formed on the lower side of the hinge section 3.As described above, the circuit configuration of this display device consists of an aluminum tape attached to the outer periphery of a medium bottle on a stainless steel water pumping pipe 6. The liquid level is detected by measuring the capacitance between 19 and 19, and the water pump 6 is connected to the metal member 20 provided around the inner stopper 5 in order to be connected to the display circuit side. In addition, a cut-out portion 21 is formed in a part of this metal member 20, and this cut-out portion 21 comes into contact with a connecting piece 22 provided at the opening of the inner bottle connected to the display circuit side. is configured to do so.

Next, the display device will be explained based on FIG. 2 and subsequent figures.

23 is an oscillator for clock pulse oscillation using a crystal oscillator or a ceramic oscillator, and 24 is a C-
A synchronizing pulse generation circuit consisting of a MOS flip-flop and a frequency divider that generates pulses such as driving pulses for liquid crystal display and charging pulses from clock pulses. 25 and 26 are analog circuits that close when the signal voltage is at high level and low level, respectively. Switch, 2
7 is a counter that is composed of a C-MOS element and counts every time a high-level signal voltage is input to the clock input terminal (CK), and 28 is a C-MOS flip-flop that outputs a high-level signal voltage to the gate terminal G. 29 is a comparator made up of an operational amplifier.

Next, the operation of this circuit will be explained.

The liquid level detection using this circuit repeats the same operation across the measurement downtime, but no charge is stored in the capacitor (Cx) made up of the pumping pipe 6 and the aluminum tape 19. Starting the explanation from the rest period, in this state the comparator 29 is powered off and in a rest state. During this period, the synchronizing pulse generating circuit 24 continues to measure the time, and when the pause time ends, the comparator 29 is turned on and a reset signal voltage as shown in FIG. 3A is output. This reset signal is input to the reset terminal R of the flip-flop circuit 30 and the reset terminal R of the counter 27, and resets both. That is, this signal causes the counter 2 to
The count value of 7 indicates 0, and a high level signal voltage is output from the output terminal of the flip-flop 30, opening the gate 31. That is, when the charging pulse signal line becomes high level, the output of the gate 31 also becomes high level.

Now, the synchronizing pulse generating circuit 24 sends out a charging pulse following the reset signal, as shown in FIG. 3B. Now, while the gate 31 is open, this pulse is input to both analog switches 25 and 26, and each time the pulse potential becomes high level, the analog switch 25 on the high potential side closes, and the other analog switch 26 opens. A capacitor (Cx) consisting of opposing electrodes is charged, and when the pulse potential becomes low level, the opening and closing of both analog switches are reversed and discharge occurs. The charging pulse from the synchronizing pulse generating circuit 24 is a pulse whose high level time is long, as shown in FIG. 3B, and the charging time is long. As the amount of liquid increases, the time required to charge the capacitor (Cx) increases, so the voltage between the opposing electrodes changes as shown in figure D, and the pumping The potential of 6 reaches the reference potential. This reference potential is determined by the resistors R ₁ and R ₂ and the power supply voltage Vdd, and is determined by the comparator 29.
The potential on the pumping pipe 6 side is input to the resistance
When the reference voltage Vs determined by R ₁ and R ₂ is reached, comparator 29 outputs a high level output to set flip-flop 30. Therefore, the third
As shown in the figure (low), a low level signal voltage is output from the output terminal of this flip-flop 30, which closes the gate 31 to prevent the charging pulse from passing through the gate 31, thereby blocking the output of the gate 31. The analog switch 26 is set to low level and turned on to discharge the charge stored in the capacitor (Cx).

During this time, the pulses passing through the gate 31 are counted by the counter 27. In this way, the charging pulse when the criterion is reached is identified. and,
The synchronizing pulse generating circuit 24 sends the latch pulse shown in FIG.
The output of is input to the latch circuit 28, and the measured liquid amount is displayed. When the measurement of the liquid amount is completed in this manner, the synchronous pulse generating circuit 24 turns off the power to the comparator 29 and enters a dormant state.

To add to the explanation here, when the power supply voltage decreases, the voltage applied to the capacitor (Cx) decreases, and the reference voltage of the comparator 29 also decreases in proportion to it, so there is no change in the number of pulses required for charging. In this way, the number of pulses corresponding to the liquid amount is counted and output to the latch circuit 28 regardless of the voltage drop of the power supply.

In this way, as the liquid volume increases, the latch circuit 2
A high-level lighting signal is output from 8 to the output line corresponding to the lower segment of the liquid level indicator 32. This output is input to the liquid crystal drive circuit 34,
The liquid crystal driving circuit 34 drives the display section 16 using liquid crystal driving pulses and blinking display pulses from the latch circuit 28 and the synchronizing pulse generating circuit 24.

Since the amount of liquid is measured in this manner, power consumption is saved and the amount of liquid can be accurately displayed.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is a partial sectional view of an air pot, FIG. 2 is a block diagram of a display device, and FIG. 3 is a timing chart of the display device. 6, 19... counter electrode, 24, 25, 31...
Voltage application circuit, 30, 27, 29... Pulse identification circuit, 28... Display circuit.

Claims (1)

[Claims for Utility Model Registration] 1. A counter electrode provided on a liquid container whose capacitance increases as the amount of liquid in the container increases, and a discharge period between the counter electrodes, which gradually increases in time duration. A voltage application circuit that applies a pulse voltage between the opposing electrodes, and a display that displays the amount of liquid in the container in stages by identifying the applied pulse when the voltage between the opposing electrodes reaches a reference voltage. A liquid container characterized by having a circuit. 2 provided on the output side of the counter electrode, and
A comparator to which the voltage between the opposing electrodes and a reference voltage are input, and outputs an achievement signal when the voltage between the opposing electrodes reaches the reference voltage; The liquid container according to claim 1, further comprising a counter for counting the number of pulses applied to the electrode. 3. The voltage application circuit includes an oscillation circuit and a frequency divider provided on the output side of the oscillation circuit in order to repeat the sequential generation of the pulse voltage with a pause period in between, and each time the voltage application circuit The liquid container according to claim 1 or 2, characterized in that the liquid container generates a signal for initializing a counter that counts the number of pulses.