JP2004020145A - Water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the thinning of electrodes due to galvanic corrosion of the electrodes by the constant DC current between the electrodes when the electrodes are immersed in water as a DC current is constantly applied between the electrodes. <P>SOLUTION: This water heater is provided with a vessel 1 storing water, a pump 4 discharging the water in the vessel 1, and a water level detecting means 5 intermittently impressing the DC voltage between a plurality of electrodes installed in the vessel 1 and detecting the presence/absence of the water by detecting whether or not the DC current flows between the electrodes. This constitution can vary the intermittent impressing time. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hot water supply device.
[0002]
[Prior art]
In FIG. 1, the conventional hot water supply apparatus has a configuration in which a DC voltage is constantly applied between a plurality of electrodes and the presence or absence of water is detected based on whether or not a DC current has flowed.
[0003]
[Problems to be solved by the invention]
However, in the above-described conventional configuration, since a direct current is always applied between the electrodes, when the electrodes are immersed in water, a direct current always flows between the electrodes, and there is a possibility that a problem such as a thinning of the electrodes due to an electric contact may occur. was there.
[0004]
[Means for Solving the Problems]
In order to solve the above-mentioned conventional problems, the present invention provides a water level detection method in which a DC voltage is intermittently applied between a plurality of electrodes installed in a container, and the presence or absence of water is detected based on whether or not a DC current flows between the electrodes. Means are provided, and the intermittent printing time is variable.
[0005]
This makes it possible to shorten the cumulative time during which DC current flows between electrodes by changing the intermittent application time of DC voltage between the electrodes according to the presence or absence of water, thereby improving the life and reliability of the electrodes. it can.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
The invention according to claim 1 is a container for storing water, a pump for discharging water in the container, and a DC voltage intermittently applied between a plurality of electrodes installed in the container, and a gap between the electrodes. Water level detecting means for detecting the presence or absence of water by whether or not a DC current has flowed, and by making the intermittent application time variable, the intermittent application time of DC voltage application between the electrodes depending on the presence or absence of water. By making the variable, it is possible to shorten the accumulated time in which a direct current flows between the electrodes, and it is possible to improve the life and reliability of the electrodes.
[0007]
According to a second aspect of the present invention, in particular, by applying the DC voltage according to the first aspect to a predetermined time after the power is turned on and when the pump is driven, it is possible to further reduce the accumulated time in which DC current flows between the electrodes. Life and reliability can be improved.
[0008]
According to the third aspect of the present invention, in particular, the DC voltage is continuously applied when the pump is driven, and the DC voltage is applied intermittently when the pump is not driven, so that the DC current is applied between the electrodes. The accumulated flow time can be shortened, the service life and reliability of the electrode can be improved, and the water level can be detected even in a state other than when the pump is driven with little change in the water level, so that the safety of the equipment can be improved.
[0009]
According to a fourth aspect of the present invention, in particular, the DC voltage application according to the first aspect of the present invention is performed by reducing the ratio of the application time of the intermittent application during the operation of the pump other than when the pump is driven. The time can be shortened, the life and reliability of the electrode can be improved, and the water level can be detected even in a state other than when the pump is driven with little change in the water level, so that the safety of the equipment can be improved.
[0010]
【Example】
(Example 1)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a water heater. In FIG. 1, reference numeral 1 denotes a container for storing water and heating or keeping the temperature. A heater 2 for heating or maintaining the water in the container 1 and a thermistor 3 for detecting the temperature of the water in the container 1 are attached to the bottom of the container. Reference numeral 5 denotes a water level detecting means for detecting a water level. A DC voltage is applied between the common electrode 5c and the opposing electrodes 5a and 5b, and the presence or absence of water is detected by detecting a flowing current value. Reference numeral 8 denotes a water supply valve which is directly connected to a water pipe and controls supply of water into the heating vessel by opening and closing the valve. Reference numeral 4 denotes a pump for discharging water in the container. Reference numeral 6 denotes an operation unit for performing operations such as drainage.
[0011]
The actual operation will be described with reference to FIG. When the power is turned on, the water level detecting means 5 applies a predetermined DC voltage (5 VDC) between the common electrode 5c and the electrodes 5a and 5b for a predetermined time, and detects whether a current is flowing through the electrode 5a or 5b. If a current flows through the electrode 5a or the electrode 5b, water has reached the electrode portion. When no current is flowing through the electrode 5b, the control means 7 constituted by a microcomputer or the like receives the signal from the water level detecting means 5 and opens the water supply valve 8 to supply a predetermined amount of water. Thereafter, the temperature is heated by the heater 2 and the temperature is monitored by the thermistor 3 to keep the temperature when the temperature reaches a predetermined temperature.
[0012]
When the user performs a water discharge operation from the operation unit, the control means 7 receives the signal, drives the pump 4 to perform a drainage operation, and sends a signal to the water level detection means 5, and the water level detection means 5 is connected to the common electrode 5c. When a predetermined DC voltage is applied between the electrodes 5a and 5b, it is detected whether or not a current flows through the electrodes 5a or 5b, and the result is sent to the control means 7. When it is detected that no current flows through the electrodes 5b, the pump is driven. Is stopped and a predetermined amount of water is supplied again. The application of the DC voltage to the electrodes is limited to the specified time after the power is turned on and the pump drive time, so the cumulative application time of the DC voltage can be shortened, and the deterioration due to electric contact etc. can be reduced and the reliability of the equipment can be reduced. Can be improved.
[0013]
The voltage application by the water level detecting means may be intermittently applied (for example, the voltage is applied only in a period of 100 ms and for a period of 200 μs).
[0014]
(Example 2)
Hereinafter, a second embodiment of the present invention will be described. The configuration is the same as that of the first embodiment, except that the voltage is applied intermittently by the water level detecting means (for example, the voltage is applied only for a period of 200 μs at a period of 100 ms) except during the pump operation.
[0015]
(Example 3)
Hereinafter, a third embodiment of the present invention will be described. The configuration is the same as that of the first embodiment, except that the DC voltage application by the water level detecting means 5 is intermittent application, and the ratio of the application time of the intermittent application is smaller than at the time of driving the pump except when the pump is driven. (For example, when the pump is driven, a voltage is applied only for a period of 200 μs at a period of 100 ms, and when the pump is not driven, a voltage is applied only for a period of 200 μs at a period of 200 ms.)
[0016]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the accumulation time which direct current flows into an electrode can be shortened, the deterioration by the electrode contact etc. can be reduced, and the life and reliability of an apparatus can be improved.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a water heater showing a first embodiment of the present invention.
DESCRIPTION OF SYMBOLS 1 Container 4 Pump 5 Water level detection means 5a, 5b Electrode 5c Common electrode

Claims (4)

A container for storing water, a pump for discharging water in the container, a DC voltage intermittently applied between a plurality of electrodes installed in the container, and water depending on whether a DC current flows between the electrodes. A water level detection means for detecting the presence or absence of water, and the intermittent application time is variable. The hot water supply apparatus according to claim 1, wherein the DC voltage is applied for a predetermined time after the power is turned on and when the pump is driven. 2. The hot water supply apparatus according to claim 1, wherein a continuous application is performed when the pump is driven, and a DC voltage is applied intermittently when the pump is not driven. 2. The hot water supply apparatus according to claim 1, wherein the ratio of the application time of the intermittent application is smaller than at the time of driving the pump than at the time of driving the pump.

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