JPH05154048A - Electric kettle - Google Patents

Abstract

PURPOSE:To provide an electric kettle having heat insulating temperatures in a plurality of steps in which when a heat insulating temperature higher than the present temperature during heat insulation is set, the present temperature is quickly adapted to reach the set heat insulating temperature and maintained thereat. CONSTITUTION:A temperature detecting means 3 compares a heat insulating temperature set by a setting means 5 with the present set heat insulating temperature. If the present heat insulating temperature is lower, a heat generating body of a heating means 2 is driven through a temperature determining means 6 and drive means 4 until a temperature lower than the set heat insulating temperature by a predetermined temperature is obtained. Thus, a heating time taken for obtaining the set heat insulating temperature can be shortened by the use of the heat generating body for heating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric water heater for heating and retaining the temperature of a liquid contained in a container.

[0002]

2. Description of the Related Art Conventionally, an electric water heater of this kind, which can set the heat retention temperature in a plurality of stages, has a new heat retention temperature higher than the previously set heat retention temperature.
Some have driven a heat-generating heating element to raise the temperature to a set temperature, and some have heated the heating element to boil once and then lower the temperature to the set temperature.

[0003]

However, in any of the conventional configurations as described above, it takes a long time to reach the set heat retention temperature by any method. That is, in the case where the heat-generating heating element has a small watt of the heating element and the ambient temperature is low, there is only the ability to maintain the temperature and the temperature may not be reached. In addition, even if the material is boiled once by a heating element for heating at a high watt, it takes a considerable time to reach the set temperature after boiling by natural cooling. There are also those that drive the heating element for heating until it reaches the set temperature, but even if the driving of the heating element is stopped at the set temperature, it will be much higher than the set temperature due to the residual heat of the heating element. There was a problem that it was difficult to reach the set temperature.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a first object of the present invention is to provide an electric water heater which quickly raises the temperature to a preset temperature by driving a heating element for heating and residual heat of the heating element. A second object is to control the driving of the heating element for heating so that the temperature of the hot water reaches the set temperature in consideration of the fact that the degree of this residual heat changes depending on the amount of liquid in the container.

A third object is to raise the temperature to the set temperature by a heating element for maintaining the heat retention temperature when the present temperature is between the set temperature and the heating end temperature.

[0006]

To achieve the above object, an electric water heater according to the present invention comprises a container for containing a liquid,
A temperature detecting means for detecting the temperature of the liquid in the container, a heating means for heating the liquid in the container, a setting means for setting a plurality of stages of heat retention temperature, and a temperature set by the setting means for detecting the temperature. When the temperature is set higher than the heat retention temperature detected by the means, the temperature determination means determines a heating end temperature lower by a predetermined temperature than the set heat retention temperature, and the temperature detection means when the temperature determination means determines the heating end temperature. Driving means is provided for driving the heating means until the detected temperature reaches the heating end temperature.

Further, a liquid amount detecting means for detecting the liquid amount in the container is provided, and the temperature determining means determines the heating end temperature from the liquid amount detected by the liquid amount detecting means and the heat retention temperature set by the setting means. It was decided to decide.

Further, a heating and heat retaining means for heating and retaining the liquid in the container is provided, and the driving means is configured to detect the temperature detected by the temperature detecting means from the heating end temperature when the heating end temperature is determined by the temperature determining means. If it is higher, the heating means is not driven and the heating and heat retaining means is driven to a set temperature.

[0009]

According to the present invention, with the above-described structure, the heating means is used to heat all the way up to a predetermined temperature lower than the heat retention temperature set higher than the present temperature, and then the remaining heat of the heating means is used. By raising the temperature to the set temperature, it is possible to bring the temperature to the set temperature in a short time.

It is also possible to prevent the degree of heating due to residual heat from varying depending on the amount of liquid used for heating, and to prevent the temperature from rising too much above the set temperature.

Further, when there is almost no difference between the preset temperature and the present temperature, the temperature can be easily raised to the preset temperature by using a heating element for maintaining the heat retention temperature with a small watt.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram of an electric water heater according to an embodiment including the first, second and third inventions.
Is a container for containing a liquid, a heating means 2 for contacting the container 1 to heat the liquid in the container 1, a heating and heat maintaining means 8 for contacting the container 1 to heat and maintain the liquid in the container 1 at a set temperature, It has a temperature detecting means 3 which is in contact with 1 to detect the temperature of the liquid in the container 1.

On the upper part of the water heater main body, there is a setting means 5 for setting a plurality of stages of heat retention temperature, and a liquid amount detecting means 7 for detecting the liquid amount in the container 1 inside. Reference numeral 6 is a temperature determining means for comparing the setting means 5 and the temperature detecting means 3 and determining the temperature at which the driving of the heating means 2 is stopped based on the outputs of the setting means 5 and the liquid amount detecting means 7 if the set temperature is higher. Again 4
Is a driving means, which drives the heating means 2 or the heating / insulating means 8 by comparing the output of the temperature detecting means 3 with the value of the temperature determining means 6 when the temperature determining means 6 determines the heating end temperature.

FIG. 2 is a circuit diagram of the above configuration. In the figure, 11 is an AC power supply and 12 is a DC power supply. The heating means 2 is composed of a heating part in which a relay contact 2a, a heating element 2c, and an AC power supply 11 are connected in series, and a control part of the relay contact 2a.
An electric current is passed through b to close the relay contact 2a. The heating and heat retaining means 8 is composed of a heating portion in which a relay contact 8a, a heating element 8c, and an AC power source 11 are connected in series, and a control portion of the relay contact 8a. And relay contact 8a
Is designed to close.

The temperature detecting means 3 for detecting the temperature of the liquid in the container 1 includes a thermistor 3a for converting the temperature into a resistance value,
It is composed of an AD converter 3b for converting the value of the thermistor 3a into a binary code. The setting means 5 is composed of a switch 5a and a resistor 5b, and when the switch 5a is pressed, the setting of the heat retention temperature is switched. The display means 9 displays the heat retention temperature (95 ° C., 85 in this embodiment) set by the setting means 5.
℃, 70 ℃ three stages) light emitting diode (LE
D) Display with 9a, 9b, 9c.

The liquid amount detecting means 7 (this embodiment is classified into four stages) includes electrodes 7a, 7b, 7c and resistors 7d, 7e, 7.
The combination of f is attached to each of the three equally divided positions in the container 1, and when the liquid amount in the container 1 reaches a certain position of each electrode, the electrodes are electrically connected to each other to output an H signal, and the H signal is output. The amount of liquid is detected by detecting the electrodes 7a, 7b, 7c which are formed.

Reference numeral 10 denotes a driving means 4 by executing a program by a microcomputer (hereinafter abbreviated as a microcomputer).
And the control of the temperature determining means 6 is realized.

FIG. 3 is a flow chart of the temperature control portion of the program stored in the microcomputer 10 according to the first aspect of the invention, and the operation thereof will be described below.

When the heat retention mode is entered, in step 21, it is detected whether or not there is an input from the setting means 5, and if there is no input, the processing ends. If there is an input from the setting means 5 in step 21,
In step 22, the display of the display means 9 is changed and the output of the temperature detection means 3 is input to determine whether the set heat retention temperature is equal to or higher than the heat retention temperature that has been set until then (step 2).
3). If the temperature set in step 23 is lower, the process returns to step 21, and if the set temperature is higher than the current set temperature, the heating means 2 is turned on in step 23, and the heating end temperature (in the present embodiment). In the example, it is set to -3 ° C) until the output of the temperature detecting means 3 reaches step 2
Repeat steps 4 and 25. When the heating end temperature is reached in step 25, the heating means 2 is turned off in step 26 and the process returns to step 21. The first invention can be easily realized with the above-mentioned configuration.

FIG. 4 shows a flow chart of the temperature control portion of the program stored in the microcomputer 10 according to the second aspect of the invention, and the operation of the second aspect of the invention will be described below.

When the heat retention mode is entered, in step 31, it is detected whether or not there is an input from the setting means 5, and if there is no input, the processing ends. If there is an input from the setting means 5 in step 31,
In step 32, the display of the display means 9 is changed, and the output of the temperature detection means 3 is input to determine whether the set heat retention temperature is equal to or higher than the heat retention temperature set up to then (step 3).
3). If the temperature set in step 33 is lower, the process returns to step 31, and if the set temperature is higher than the current set temperature, the output of the liquid amount detecting means 7 is input in step 34, and this input is performed in step 35. The heating end temperature is determined by. Next, in step 36, the heating means 2 is turned on, and in step 37, until the output of the temperature detection means 3 reaches the heating end temperature determined in step 35, step 3
Repeat steps 6 and 37.

When the heating end temperature is reached in step 37, the heating means 2 is turned off in step 38 and the process returns to step 31. The second invention can be easily realized with the above-mentioned configuration.

FIG. 5 shows a flow chart of the temperature control portion of the program stored in the microcomputer 10 according to the third aspect of the invention, by which the operation of the third aspect of the invention will be described.

When the heat retention mode is entered, it is detected in step 41 whether or not there is an input from the setting means 5, and if there is no input, the processing ends. If there is an input from the setting means 5 in step 41,
In step 42, the display of the display means 9 is changed, and the output of the temperature detection means 3 is input to determine whether the set heat retention temperature is equal to or higher than the heat retention temperature set up to then (step 4).
3). If the temperature set in step 43 is lower, the process returns to step 41. If the set temperature is higher than the current set temperature, the output of the liquid amount detecting means 7 is input in step 44, and this input is performed in step 45. The heating end temperature is determined by. When the heating end temperature is determined, the heating end temperature is compared with the current temperature in step 47. If the current temperature is lower, the heating means 2 is turned on in step 47, and step 48 is performed.
Then, steps 47 and 48 are repeated until the output of the temperature detection means 3 reaches the heating end temperature determined in step 45. When the heating end temperature is reached in step 48, the heating means 2 is turned off in step 49 and the process returns to step 41.

If the current temperature is higher in step 46,
In step 50, the heating and heat retaining means 8 is turned on, and in step 5 until the output of the temperature detecting means 3 reaches the set temperature.
Repeat 0, 51. When the set temperature is reached in step 51, the heating and heat retaining means 8 is turned off in step 52 and the process returns to step 41. The third aspect of the invention can be easily realized with the above configuration.

[0027]

As described above, according to the first aspect of the present invention, the temperature can be raised quickly to the set temperature by the heating means. The power consumption can be reduced as compared with the case where the heating means is driven continuously for a long time.

According to the second aspect of the invention, since the heating end temperature is set according to the liquid amount, it is possible to prevent the set temperature from being greatly exceeded by the overshoot of the heating element.

According to the third aspect of the present invention, even when the current temperature is approaching the set temperature, the set temperature can be raised to the set temperature by the heating means having a low wattage, and the convenient electric water heater is provided. can do.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of an electric water heater including first, second and third inventions of an embodiment of the present invention.

FIG. 2 is a circuit diagram of the electric water heater.

FIG. 3 is a flowchart showing the operation of the first invention.

FIG. 4 is a flowchart showing the operation of the second invention.

FIG. 5 is a flowchart showing the operation of the third invention.

[Explanation of symbols]

 1 Container 2 Heating Means 3 Temperature Detecting Means 4 Driving Means 5 Setting Means 6 Temperature Determining Means 7 Liquid Quantity Detecting Means 8 Heating Insulating Means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshitada Nakao 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A container for containing a liquid, a temperature detecting means for detecting the temperature of the liquid in the container, a heating means for heating the liquid in the container, and a setting means capable of setting a heat retaining temperature in a plurality of stages. When the temperature set by the setting means is set higher than the heat retention temperature detected by the temperature detection means, a temperature determination means for determining a heating end temperature lower by a predetermined temperature than the set heat retention temperature, and the temperature determination An electric water heater provided with driving means for driving the heating means until the temperature detected by the temperature detecting means reaches the heating end temperature when the means determines the heating end temperature. 2. A liquid amount detecting means for detecting the liquid amount in the container is provided, and the temperature determining means determines the heating end temperature based on the liquid amount detected by the liquid amount detecting means and the heat retention temperature set by the setting means. The electric water heater according to claim 1. 3. A heating and heat retaining means for heating and retaining the liquid in the container is provided, and the driving means is heating means if the temperature detected by the temperature detecting means is higher than the heating end temperature when the heating end temperature is determined by the temperature determining means. The electric water heater according to claim 1 or 2, wherein the heating and heat retaining means is driven to a set temperature without being driven.