JPH0351717Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrode for detecting whether the amount of water in a liquid container such as an electric water heater is insufficient.

[Conventional technology]

Conventionally, as a means for detecting a lack of water in the liquid container of an electric water heater, for example, a metal pipe for detecting water amount is connected to a metal liquid container, and a constant current is passed between the liquid container and the pipe. A device that determines whether the amount of water in a liquid container has fallen below a predetermined level based on changes in electrical conductivity between There are methods that determine whether the amount of water has fallen below a predetermined level.

[Problem that the invention attempts to solve]

However, in the former case, it is necessary to connect a metal pipe to the liquid container in addition to the liquid level display pipe, which increases the number of parts and makes the structure complex. Since a current is passed between the liquid container and the liquid container, the water in the liquid container is electrolyzed, resulting in deterioration or discoloration of the water. In addition, the latter method has a drawback, which is not the same as the former method, in that if water scale or the like adheres to the liquid level display pipe, the detection accuracy decreases.

The present invention was developed with the above-mentioned considerations in mind, and its purpose is to have a simple structure, to be hygienic without changing the quality or discoloration of the water in the liquid container, and to be hygienic. An object of the present invention is to provide a water shortage detection electrode that can reliably detect a water shortage.

[Means for solving problems]

In order to achieve the above-mentioned object, the water shortage detection electrode according to the present invention is arranged around the outer circumference of a pipe that is connected to a liquid container, and is equipped with a bobbin made of an insulating material and having a flange on at least one end. ,
two electrode bodies disposed on the outer periphery of the bobbin in a mutually insulated state; a holder made of an insulating material provided to cover and hold the electrode bodies; and one end connected to the outside of the flange. and a conductive shield cover disposed around the outer periphery of the holder such that the other end engages with an end of the holder opposite to the flange.

[Effect]

In the water shortage detection electrode according to the present invention, an insulating bobbin with a flange is provided on the outer periphery of a pipe arranged to communicate with a liquid container, and the electrode is sandwiched between the bobbin and a holder. The electrode bodies are insulated from each other, and a conductive shield cover is provided on the outside of the holder, and this shield cover holds the holder on the bobbin, ensuring that the outer circumference of the pipe is Installation can be done on. The electrode body is provided outside the liquid container and the pipe connected to the liquid container, so it is hygienic because it does not come into contact with the water in the liquid container.Moreover, no current flows through the water, so electricity is generated. Since no decomposition occurs, the water never deteriorates in quality or changes in color.
Furthermore, even if limescale adheres to the pipe, a shortage of water can be reliably detected.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on FIGS. 1 to 5.

FIG. 5 shows an electric water heater to which the present invention is applied, and in the figure, 1 is a case body, 2 is a lid provided on the upper part of the case body 1 so that it can be opened and closed, and can be attached and detached, and 3 is a bottom body. Reference numeral 4 denotes a liquid container made of metal such as stainless steel, in which water W is stored. 5 is a heater wound around the lower outer periphery of the liquid container 4.

Reference numeral 6 denotes a liquid level display tube as a pipe made of an insulating and transparent material such as a transparent glass tube, the lower end of which is connected to the liquid container 4 via the lower connecting tube 7A, and the upper end thereof is connected to the liquid container 4 through the lower connecting tube 7A. It is connected to the spout 8 via the connecting pipe 7B, and also functions as a spout path for the water W in the liquid container 4. Reference numeral 9 denotes a transparent window formed in the case body 1 to accommodate the liquid level display tube 6.

Reference numeral 10 denotes an electrode for detecting water shortage, which is provided on the outer periphery of the lower part of the liquid level display tube 6, and its detailed structure is as shown in FIGS. 1 to 3.

That is, in FIGS. 1 to 3, reference numeral 11 denotes a cylindrical bobbin that is provided in close contact with the outer periphery of the liquid level display tube 6, and is made of an insulating material such as polypropylene or ABS resin. Projections 11a, 11a are provided in 180° symmetrical positions in the length direction. A flange portion 11B is formed integrally with the upper portion of the body portion 11A.

Reference numerals 12 and 13 designate a first electrode body and a second electrode body which are formed symmetrically by curved copper plates, for example, and a protrusion 1 is provided on the outer periphery of the body 11A of the bobbin 11.
1a and 11a so as to be in close contact with each other and insulated from each other. Note that 12A and 13A are lead connection parts.

14 is a first electrode body 12, a second electrode body 1
A cylindrical holder for covering and holding 3.
It is made of the same material as the bobbin 11.

Reference numeral 15 denotes a conductive shield cover provided around the outer periphery of the holder 14, and is formed of, for example, a nickel-plated stainless steel plate into a cylindrical shape. In addition, 15
A is a lead connection part.

The water shortage detection electrode 10 made of the above-mentioned members is attached to the liquid level display tube 6 in the following manner.

That is, the first electrode body 12 and the second electrode body 13 are provided on the outer periphery of the body portion 11A of the bobbin 11 so as to be in close contact with each other while being insulated from each other. in this case,
The upper end portions of both electrode bodies 12 and 13 are brought into contact with the lower end portion of the flange portion 11B of the bobbin 11. Next, the holder 14 is fitted onto the outside so as to cover both electrode bodies 12 and 13, and then the shield cover 15 is fitted onto the outer periphery of the holder 14, and the lower end of the shield cover 15 is bent inward to close the holder 14. While the lower end is engaged, the upper end is bent inward and engaged with the upper end surface of the flange portion 11B. After the liquid level indicating tube 6 is inserted through the body 11A of the bobbin 11, the liquid level indicating tube 6 is connected to the liquid container 4 via the lower connecting tube 8D.

Figure 4 shows the circuit configuration for detecting water shortage, and in the figure, 20 is a so-called one-chip microcomputer (hereinafter referred to as microcomputer).
It consists of CPU21, ROM22, RAM23, etc. and controls the electric water heater.

Reference numeral 31 denotes an oscillation circuit made of, for example, a crystal oscillator, which is connected to the first electrode body 12 via a lead wire 32. Also, 33 is a switching circuit,
It is connected to the second electrode main body 13 via a lead wire 34 and connected to the microcomputer 2 via a lead wire 35.
It is connected to 0. 36 is a lead wire for connecting the shield cover 15 to the common terminal, 41 is an alarm such as a piezoelectric buzzer, and 42 is an indicator light such as an LED.

In the above configuration, when the oscillation circuit 31 is emitting electrical vibrations of, for example, 4MH _Z , the water surface in the liquid container 4 is lowered to detect a water shortage, as shown by the virtual line a in FIG. Electrode 1
When the position is lower than 0, the first electrode body 12
Since the electrostatic capacitance between the oscillation circuit 31 and the second electrode body 13 is small, and the coupling between the oscillation circuit 31 and the switching circuit 33 is loose, the switching circuit 33 outputs a signal indicating water shortage, and based on this, An alarm command is output from the microcomputer 20, and the alarm 41
sounds and the indicator light 42 flashes.

Then, when water is replenished in the above state and the water level in the liquid container 4 becomes higher than the water shortage detection electrode 10 as shown by the imaginary line b in FIG. 5, the first electrode body 12 and the second Since the electrostatic capacitance between the electrode body 13 and the oscillation circuit 31 increases, and the coupling between the oscillation circuit 31 and the switching circuit 33 becomes tight, the signal indicating the lack of water quantity from the switching circuit 33 is stopped, and the alarm from the microcomputer 20 is stopped. Since the command stops, the alarm 41 stops sounding and the indicator light 42
will also stop blinking. That is, when the water level in the liquid container 4 is higher than the water shortage detection electrode 10, no signal is output from the switching circuit 33. Note that these operations are performed by the microcomputer 20.
Processing is performed based on the program stored in the ROM 22 of the computer.

In the above embodiment, the flange portion 11B is provided at the upper end of the bobbin 11, but it may be provided at the lower end, or at both the upper and lower ends of the bobbin 11.

[Effect of idea]

As explained above, the water shortage detection electrode according to the present invention includes an insulating bobbin with a flange provided around the outer periphery of a pipe connected to a liquid container, and the electrode is sandwiched between the bobbin and the holder. The two electrode bodies are insulated from each other, and a conductive shield cover is provided on the outside of the holder, and this shield cover holds the holder on the bobbin, ensuring that the pipe is securely attached. It can be attached to the outer periphery of the The electrode body is provided outside the liquid container and the pipe connected to the liquid container, so it is hygienic because it does not come into contact with the water in the liquid container.Moreover, no current flows through the water, so electricity is generated. Since no decomposition occurs, the water never deteriorates in quality or changes in color. Furthermore, even if limescale adheres to the pipe, a shortage of water can be reliably detected.

Therefore, according to the present invention, there is a water shortage detection method that has a simple structure, is hygienic because it does not alter the quality or discoloration of the water in the liquid container, and can reliably detect a water shortage. electrodes can be obtained.

[Brief explanation of the drawing]

1 to 5 show an embodiment of the present invention,
Fig. 1 is a sectional view showing the vicinity of the attachment part of the electrode for detecting water shortage, Fig. 2 is an exploded perspective view showing an example of the electrode for detecting water shortage, Fig. 3 is a sectional view taken along the - line in Fig. 1, Figure 4 is a block diagram showing the circuit configuration.
FIG. 5 is a sectional view showing an electric water heater to which the present invention is applied. 4...liquid container, 6...pipe, 11...bobbin, 11B...flange section, 12, 13...electrode body, 14...holder, 15...shield cover.

Claims (1)

[Scope of utility model registration request] a bobbin made of an insulating material and provided with a flange at at least one end and disposed on the outer periphery of a pipe connected in communication with a liquid container; and two bobbins disposed on the outer periphery of the bobbin in a mutually insulated state. An electrode body, a holder made of an insulating material provided to cover and hold the electrode body, one end of which is engaged with the outside of the flange portion, and the other end of which is connected to the outside of the flange portion of the holder. An electrode for detecting water shortage, comprising a conductive shield cover disposed around the outer periphery of the holder so as to engage with the end portion.