JPH02168121A - Detecting device of water level - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a water level detection device that accurately measures the amount of water and is applied to FI3.

2. Description of the Related Art As a conventional means for measuring the amount of water, a method has been proposed in which water is measured by temporally controlling a solenoid valve provided at the bottom of a water container. Furthermore, as another means of measuring the amount of water, a method has been proposed in which an electrode is provided around a water container and the water level is detected by a change in capacitance between the water and the electrode.

Problems to be Solved by the Invention In the conventional method of measuring water volume by controlling the opening and closing of a solenoid valve, the outflow flow rate of water changes depending on the opening area of the solenoid valve and the initial water level of the water container. The problem with valve opening/closing control is that highly accurate measurement is difficult.

In addition, in the method of measuring the amount of water by detecting the water level by changing the capacitance between the electrodes, since the water is energized, it is necessary to use an isolation transformer to prevent electric shock, which results in the equipment becoming larger. There was an issue.

The present invention solves the above problems, and improves the accuracy of water measurement with a simple configuration, and is compact! The purpose of the present invention is to provide a water level detection device that is free from the risk of electric shock.

Means for Solving the Problems In order to solve the above problems, the water level detection device of the present invention is (
1) a water container made of an electrical insulator, a first electrode conductive to the water inside the water container, a second electrode provided in a strip shape in contact with the outside of the side wall of the water container, and the first electrode. A control circuit section that converts the capacitance between the electrode and the second electrode into an oscillation frequency, and an impedance element is inserted in series between the I's 1 electrode and the control circuit section. This is what I did.

Function: With the above configuration, the amount of water can be measured continuously and accurately using the capacitance method, and the human body can be protected from electric shock by the withstand voltage and impedance of the impedance element.

EXAMPLE Hereinafter, an example of the present invention will be explained based on FIGS. 1 and 2.

In the figure, 1 is a water container made of an electrical insulator, 2 is a first electrode conductive to the water inside the water container 1, and 3 is a second electrode provided in a strip shape in contact with the outside of the side wall of the water container 1. electrode, 4
5 is a control circuit unit that converts the capacitance between the first electrode 2 and the second electrode 3 into an oscillation frequency, and 5 is a water pipe for supplying measured water. 6 8 is an oscillation circuit using the capacitance between the pair of electrodes 2 and 3; 9 is a microcomputer that counts the number of output pulses of the oscillation circuit 8;

FIG. 3 shows another embodiment, in which a fixed resistor for preventing electric shock is used as the impedance element 7. The other configurations are the same as those in the previous embodiment.

The operation of the above configuration will be explained. The water level of the water container 1 is measured by detecting a change in capacitance between the first electrode 2 and the second electrode 3 which are electrically connected to the water inside the water container 31. For example, as shown in Fig. 2, an oscillation circuit 8 is configured using the capacitance between a pair of electrodes, and the number of output pulses of this oscillation circuit 8 is counted by a microcomputer 9 and converted to the water level. can do. It has been experimentally confirmed that the correlation between the water level and the oscillation period is linear as shown in Figure 4.

Here, the impedance cord 6 in FIG. 2 can protect the human body from Ii by using, for example, a wire with a withstand voltage of 1000 V and an impedance equivalent to 1 MΩ or more.
In addition, the impedance cable 7 in FIG. 3 can similarly protect the human body from electric shock by using, for example, a withstand voltage of 1000 V and a resistance of jJ I MΩ or more, so an isolation transformer is not required and a small and safe water level can be used. A detection device can be configured.

Effects of the Invention As is clear from the description of the embodiments described above, according to the present invention, the amount of water can be measured continuously and accurately using a capacitance method, and electric shock can be prevented using an impedance element using a capacitor or a fixed resistor. Due to its scarcity, equipment can be made smaller, and its industrial value is great.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the water level detection device of the present invention, Fig. 2 is a circuit diagram showing the control circuit section thereof, and Fig. 3 is a circuit diagram of the control circuit section showing an embodiment of the water level detection device of the present invention. FIG. 4 is a characteristic diagram showing the correlation between the water level and the oscillation period converted by the control circuit section. ■... Water container, 2... First electrode, 3... Second electrode (lid, 4... Control circuit section, 6, 7... Impedance element. Name of agent: Patent attorney Awano r “Takashi and others I name f --
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Claims (1)

[Claims] A water container made of an electrical insulator, a first electrode conductive to water inside the water container, a second electrode provided in a strip shape in contact with the outside of a side wall of the water container, and the first electrode. Said second
a control circuit section that converts capacitance between the first electrode and the control circuit section into an oscillation frequency, and an impedance element is inserted in series between the first electrode and the control circuit section.