JP2666999B2 - Electric water heater - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric water heater that heats and keeps liquid stored in a container.

2. Description of the Related Art Conventionally, this type of electric water heater has a configuration as shown in FIG. 4 (a). That is, as shown in FIG. 4 (a), a marking 2 indicating fullness is provided at the position of fullness inside the container 1, or an attachment attached to the outer case 3 for confirming the water level in the container 1. At the full water display position A of the frame 4, the character "full water" as shown in FIG. 4 (b) in which this portion is enlarged is displayed, and the user can check whether the float 5 indicating the water level has reached this display position. It was confirmed visually.

SUMMARY OF THE INVENTION However, in such a conventional configuration, it is difficult to determine whether or not the water is full by simply displaying a mark, and the water in the container 1 is heated even if the water is filled above the full water position. When boiling, there was a problem that hot water might spill out of the discharge port due to thermal expansion of water.

The present invention solves the above-mentioned conventional problems, and divides the water level detection position depending on whether the water temperature is lower than or equal to a predetermined temperature, and when the water level reaches each detection position, it is possible to reliably detect an abnormality and generate heat. It is an object of the present invention to provide an electric water heater that can stop the heating of the body and notify the danger by informing the user of the danger.

Means for Solving the Problems In order to solve the above problems, the electric water heater of the present invention is a container that stores a liquid, a heating element that heats the container, and a heating unit that controls energization of the heating element. A temperature detecting means for detecting a temperature in the container, a water level pipe connected to the container for indicating a water level in the container, and a first water level detecting means provided at an upper first detection position of the water level pipe. And the first
Second water level detecting means provided at a second detection position above the water level detecting means, notifying means for giving notification, and first water level detecting means if the temperature detecting means detects a temperature lower than a predetermined temperature. If the temperature is equal to or higher than the predetermined temperature, the second water level detecting means is driven, and if the water level reaches the set height, the heating means is turned on until the water level becomes lower than the set height. Control means for turning off and operating the notifying means.

According to the above configuration, when the water temperature is low, the water level rises due to thermal expansion, so that the water level is taken into consideration and the first water level detecting means performs full-water detection at the first detection position to report the water level. Since the water level is small, the water level does not rise to such an extent that the hot water spills from the discharge port even when the water level reaches near the second detection position.
The water level detection means of FIG. 2 performs detection to notify, and in any case, the heat generation means is turned off to prevent hot water from spilling from the discharge port at the time of boiling due to too much water.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a full water detecting process of an electric water heater according to one embodiment of the present invention. In FIG.
The water level tube 11 is connected to the upper and lower parts of a container 12 for containing a liquid, and displays the water level in the container 12 to the outside by a float 13 that floats and sinks depending on the volume of the liquid. The L detecting means 14, which is the first water level detecting means, is attached to the water level tube at a height with a mark of full water. The H detection means 15, which is the second water level detection means, is located above the L detection means 14 (here, the height is about 5 mm at which the water does not reach even if it is thermally expanded when heated at a water level lower than the first detection position). Installed. These L detecting means 14 and H detecting means 15
Is always full, and its output is
16 is entered. The heating means 17 controls a heating element 18 attached to the bottom of the container 12. Temperature detection means 19
Is for detecting the temperature of the bottom surface of the container 12 and inputting it to the control means 16. The notifying means 20 notifies the outside that the water is full when the water level detecting means detects that the water is full. The control means 16 receives the outputs of the L detection means 14, the H detection means 15 and the temperature detection means 19 and controls the driving of the heating means 17 and the notification means 20.

The electric water heater having the above configuration will be described in more detail.

FIG. 2 is a circuit diagram of full water detection processing of the electric water heater according to the embodiment of the present invention. In FIG. 2, an AC power supply 21 and a DC power supply 22 supply a voltage to the entire circuit. The control means 16 is composed of a microcomputer (hereinafter referred to as a microcomputer) 23. The L detecting means 14 and the H detecting means 15 include photodiodes 24 and 25 and phototransistors 26 and 25, respectively.
When the float 13 reaches the respective detection position due to the amount of water in the container 12, the light of the photodiode 24 or 25 is blocked and the phototransistor 26 or 27 is turned off. , Microcomputer 23
Is input with "H". On the other hand, if the float 13 is not at the respective detection positions, the phototransistor 26 or 27 receives light from the photodiode 24 or 25 and turns on. At this time, “L” is input to the microcomputer 23. The heating means 17
The microcomputer 23 includes a relay contact 28, a relay coil 29, and a transistor 30. When "H" is output from the microcomputer 23 to the base of the transistor 30 via a resistor, a current flows through the relay coil 29 through the transistor 30, and the relay contact 28 The heating element 18 is closed and heated. The notifying means 20 is constituted by an LED 31 and a buzzer 32 for indicating when the water is full, and is driven by a command of the microcomputer 23 when the water is detected to notify the user visually and audibly. The temperature detecting means 19 has a comparator 33. A reference potential divided by the resistors 34 and 35 is input to a positive input terminal of the comparator 33, and a thermistor 36 and a thermistor 36 are specified to a negative input terminal. Is detected (85 ° C. in this embodiment) or more, a potential divided by a resistor 37 having a resistance value such that the potential becomes higher than the reference voltage inputted to the + input terminal is inputted. The output is input to the microcomputer 23.

FIG. 3 is a flowchart showing the main operation of the microcomputer 23 in the full water detection process. When water is injected into the electric water heater, first, in step 41, the output of the temperature detecting
In step 42, the microcomputer 23 determines whether or not the water temperature is 85 ° C. or higher. If the temperature is lower than 85 ° C., the L detection means 14 inputs the signal in step 43. If 85 ° C. or higher, the microcomputer 23 determines H in step 44. Based on the input signal of the detection means 15, it is determined at step 45 whether or not the water is full. If the water is not full in step 45, the process proceeds to the next step.If the water is full, in step 46, the power supply to the heating element 18 is stopped by the heating means 17 and the notification means 20 is driven until the water level becomes lower than the set height. Then, proceed to the next step.

As described above, according to the present embodiment, when the temperature is lower than the predetermined temperature, the water level is above the first detection position and above the second detection position when the temperature is higher than the predetermined temperature. ,
This allows safe operation.

Advantageous Effects of the Invention As described above, according to the present invention, it is possible to reliably prevent hot water from spilling out of the discharge port at the time of boiling due to too much water in a container with a simple configuration, and to provide a safe electric water heater. Can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram of full water detection processing of an electric water heater showing an embodiment of the present invention, FIG. 2 is a circuit diagram of full water detection processing of the electric water heater, and FIG. 3 is the same electric water heater. FIG. 4 (a) is a partially cutaway perspective view of a conventional electric water heater, showing a main operation of the microcomputer for the full water detection process.
FIG. 4B is an enlarged view of a portion A in FIG. 4A. 11 ... water level tube, 12 ... container, 14 ... L detection means, 15 ...
H detection means, 16 control means, 17 heating means, 18
Heating element, 19 …… Temperature detection means, 20 …… Notification means, 23 ……
Microcomputer, 24, 25 Photodiode, 26, 27 Phototransistor, 28 Relay contact, 29 Relay coil, 30 Transistor, 31 LED, 32 Buzzer, 3
3… Comparator, 34,35,37… Resistance, 36… Thermistor.

Claims (1)

(57) [Claims] 1. A container for containing a liquid, a heating element for heating the container, and heating means for controlling energization of the heating element.
Temperature detecting means for detecting the temperature in the container, a water level pipe connected to the container for indicating the water level in the container, and first water level detecting means provided at an upper first detection position of the water level pipe. A second water level detecting means provided at a second detection position above the first water level detecting means, an informing means for informing, and the temperature detecting means if the temperature is lower than a predetermined temperature. The first water level detecting means is driven, and the second water level detecting means is driven when a predetermined temperature or more is detected. If the respective water level detecting means reach the set height, the water level is lower than the set height. An electric water heater comprising a control unit for turning off the heating unit until the notification unit operates.