JP3195998B2 - Electric water heater - Google Patents

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 keeping a liquid contained in a container.

[0002]

2. Description of the Related Art Conventionally, in this type of electric water heater, a heating means for heating a liquid in a container is in contact with a bottomed cylindrical container, and a temperature detecting means in contact with the container detects the temperature in the container. Detect. When the start of heating is detected by the heating start means, the heating means is driven by the energizing means, and the storage means stores the time for the first predetermined temperature width rise measured by the timing means, and thereafter, the boiling detection means sets the time When the time measured by the means is larger than a certain ratio of the value of the storage means, the heating means is stopped and the boiling is detected.

[0003]

However, in such a conventional configuration, there is a possibility that boiling may be erroneously detected depending on the temperature of the hot water at the start of heating. Is disclosed.

Further, for example, when a container filled with water is gradually cooled to a warming temperature, hot water having a lowered temperature accumulates at the bottom of the container, causing a temperature difference with the upper layer of the hot water. When reheating is performed in this state, convection around the bottom heated by the heating element continues for a while, and eventually changes to convection to the upper layer. At the time of the convection centered on the bottom, it is as if a small amount of hot water is heated, and the temperature curve is very steep as shown in FIG. 8 (a). Therefore, based on the short time measured at the steep point of the temperature curve, the boiling point is erroneously detected when the convection is completed. In particular, this factor becomes even more problematic due to the increasing capacity of the weight, which has recently become larger, or the function of performing natural cooling down to a heat retaining temperature of 85 ° C. or 70 ° C.

[0005] In another example, in the boiling detection operation, after a reference value is created, the time until a predetermined temperature rise is unconditionally measured thereafter. Therefore, as shown in FIG. When water is added to the water, the water temperature drops and rises again.However, the time is measured without taking this into account. To detect boiling.

An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to detect a correct boiling of a liquid in a container irrespective of a volume and a heat retaining temperature.

[0007]

Means for Solving the Problems The present invention to achieve the above object, a container for accommodating the liquid, a temperature detecting means for detecting a pre-SL solution temperature of a heating means for heating the pre-SL solution body An energizing means for energizing the heating means, a time keeping means for measuring and keeping a rising time for each first predetermined temperature width, and a time for raising the first predetermined temperature width measured by the time keeping means. A storage means, a boiling detection means for stopping the heating means when the time measured by the time measurement means becomes larger than a certain ratio of the value of the storage means, and a second predetermined time for energizing the heating means; and a on-off means you reenergize after a predetermined time stopping, to initiate the kettle
The heating means is turned on and off by the on / off means.
Energize for a first predetermined time and then stop energizing for a second predetermined time
And then re-energize before the timing means and the storage means
And the boiling detection means are operated to perform boiling detection.
It was an electric kettle .

[0008] Further , during the heat retention, the temperature detecting means is operated at a predetermined temperature.
If the following is detected, the on / off
And then re-energize before the timekeeping means and the storage means
And boiling detection means to perform boiling detection
It was made.

Further, when the temperature detected by the temperature detecting means when the heating is started by the heating starting means is higher than a predetermined temperature, the timer means is driven, and when the temperature is low, the on / off means is driven.

[0010] In addition, the temperature detecting means is provided with a low second predetermined temperature range.
Detection of lowering that re-activates the ON / OFF means when detecting lower
Means.

[0011]

According to the present invention, in the above-described structure, the difference in water temperature in the vessel at the start of water heating is reduced by turning on and off the energizing means for a predetermined time, the convection is made constant, and then a reference value is created. Detection can be performed.

Further , when the temperature decreases during the heat insulation,
By turning on / off the power supply for a fixed period of time,
Create a reference value after reducing the difference and keeping the convection constant.
Thus, stable boiling detection can be performed.

Furthermore, when the temperature at the start of water heating is high, the heating means is not turned on / off, so that a stable reference value can be created.

After the reference value has already been created,
Water is added when comparing the time
Even if there is no rise and the timekeeping time increases,
Where the reference value can be recreated.

[0015]

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to FIG.

FIG. 1 is a block diagram of an electric water heater according to a first embodiment of the present invention, wherein 1 is a container for containing a liquid, 2 is a heating means for contacting the container 1 and heating the liquid in the container 1,
Reference numeral 3 denotes a temperature detecting unit which is in contact with the container 1 and detects the temperature of the liquid in the container 1, and 4 denotes an energizing unit for energizing the heating unit 2.

Numeral 9 denotes a heating start means for forcibly starting water heating or automatically starting water heating when the temperature becomes lower than a certain value.

Reference numeral 5 denotes on / off means, 6 denotes time measuring means, 7 denotes storage means, 8 denotes boiling detection means, and the on / off means 5
When the heating start signal of the heating start means 9 is inputted, the energizing means 4 is energized for a first predetermined time (10 seconds in this embodiment), and thereafter, for a second predetermined time (1 in this embodiment).
(0 seconds) The energizing means 4 is turned off. When the second predetermined time has elapsed, the energizing means 4 is driven again, and the time measuring means 6 starts measuring time. The time keeping means 6 keeps measuring the time for raising the first predetermined temperature width (in this embodiment, in units of 0.5 ° C.), and stores the first time taken (hereinafter referred to as a reference value) in the storage means 7. . When the storage means 7 stores the reference value, the boiling detection means 8 compares the constant value (three times in this embodiment) of the reference value with the 0.5 ° C. rise time measured by the time measurement means 6. When the time measured by the timer 6 increases, the power supply to the power supply 4 is stopped.

FIG. 2 is a circuit diagram of an electric water heater according to a first embodiment of the present invention. In FIG. 2, reference numeral 12 denotes an AC power supply. The heating means 2 includes a first heating element 2a for heating the liquid in the container, and a second heating element 2b for heating the liquid in the container with a lower heating power than the first heating element 2a. . The energizing means 4 includes relay contacts 4 a and 4 connected in series with the respective heating elements of the heating means 2 and the AC power supply 12.
and relay coils 4c and 4d for controlling the relay contacts 4a and 4b.
A current flows through the relay contacts d and the relay contacts 4a and 4b are closed. The temperature detecting means 3 includes a temperature-sensitive element 3a for converting a temperature into a resistance value, and an AD converter 3b for converting the value of the temperature-sensitive element 3a into a binary code. Reference numeral 9 denotes a part of the heating start means, which is constituted by a switch for forcibly starting water heating. Reference numeral 13 denotes a microcomputer (hereinafter, abbreviated as a microcomputer).

FIG. 3 shows a microcomputer 1 according to a first embodiment of the present invention.
3 shows a flowchart of a control portion in the kettle of a program stored in, for explaining the operation by Re this.

When the temperature is forcibly detected during the heat retention or when the temperature is detected to be lower than a certain temperature, the heating means 2 is turned on (step 1). Thereafter, it waits until the time to turn on the heating means 2 unconditionally elapses (step 2), and when the time to turn on elapses, turns off the heating means 2 (step 3), and the time to unconditionally turn off elapses (Step 4), and when the time to turn off has elapsed, the heating means 2 is turned on again, the time keeping means 6 is cleared (Step 5), and the time required to rise by 0.5 ° C. is measured (Step 6, Step 6). 7). When the rise of 0.5 ° C. is detected in step 7, the value of the time counting means 6 at that time is stored in the storage means 7 (step 8).

Next, in steps 9 to 12, the timing means 6 measures the time required for the temperature to rise by 0.5 ° C.
When the temperature rises, the timed value is cleared and the time to rise 0.5 ° C again is started. In the meantime, the value of three times the time stored in the storage means 7 is continuously compared with the time during the time counting by the time counting means 6, and when the value of the time counting means 6 increases, the heating means 2 is regarded as boiling. Turn off (Step 1
3) It has a configuration.

As described above, according to the first embodiment, a configuration is adopted in which the reference value for short boiling detection is not erroneously generated by the water heater when the temperature difference between the upper and lower sides of the water occurs at the start of the water heater. It becomes possible.

(Embodiment 2) A second embodiment of the present invention will be described with reference to FIGS. The same components as those described in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 4 is a block diagram of an electric water heater according to a second embodiment of the present invention. The difference from the first embodiment is that a drop detecting means 10 is added. When the temperature detecting means 3 detects that the temperature detecting means 3 has decreased by more than a second predetermined temperature range (3 ° C. in this embodiment), the operation of the time keeping means 6, the storage means 7 and the boiling detecting means 8 is determined. It is configured to be stopped and restarted from the on / off means 5.

FIG. 5 is a flowchart showing a control portion of the program stored in the microcomputer 13 of the second embodiment during water heating, and the operation will be described with reference to FIG.

When the water heater is started in the same manner as in FIG. 3, the heating means 2 is turned on and off in steps 21 to 24.

When the heating means 2 is driven again in step 25, the time keeping means 6 is cleared and the time during which the temperature rises by 0.5 ° C. is measured (steps 27 and 28). If the temperature detecting means 3 detects a temperature drop of 3 ° C. or more during this time, the operation is restarted from step 21 (step 26). Further, when a rise of 0.5 ° C. is detected in step 28, the value of the time counting means 6 at that time is stored in the storage means 7 (step 29).

Next, in steps 30 to 34, the timing means 6 measures the time required for the temperature to rise by 0.5 ° C.
When the temperature rises by 0 ° C., the timed value is cleared, and the time to rise by 0.5 ° C. is started again. In the meantime, the value of three times the time stored in the storage means 7 is continuously compared with the time during the time counting by the time counting means 6, and when the value of the time counting means 6 increases, the heating means 2 is regarded as boiling. It is configured to be turned off (step 35). During this time, when the temperature detecting means 3 detects a temperature decrease of 3 ° C. or more, the operation is restarted from step 21 (step 31).

As described above, according to the second embodiment, it is possible to prevent the water from being erroneously boiled due to the temperature drop due to the addition of water during the water heating.

(Embodiment 3) A third embodiment of the present invention will be described with reference to FIGS. The same components as those described in the second embodiment are denoted by the same reference numerals, and description thereof is omitted.

FIG. 6 is a block diagram of an electric water heater according to a third embodiment of the present invention. The difference from the second embodiment is that a comparison means 11 is added. The comparison means 11 receives the heating start signal from the heating start means 9, and if the temperature of the temperature detection means 3 is equal to or higher than a predetermined temperature (92 ° C. in this embodiment), the timer means 6 sets the time measurement means 6 to a temperature lower than the predetermined temperature In this case, the on / off means 5 is driven.

FIG. 7 is a flow chart showing a control portion of the program stored in the microcomputer 13 of the third embodiment during water heating, and the operation will be described with reference to FIG.

When the temperature is forcibly detected during the heat retention or when it is detected that the temperature is lower than a certain temperature, the temperature detecting means 3 judges whether the temperature is lower than or higher than a predetermined temperature (92 ° C. in this embodiment). Step 41), when the temperature is lower than the predetermined temperature, FIG.
In the same manner as in steps 42 to 45, the heating means is turned on and off.

When the temperature is equal to or higher than the predetermined temperature in step 41, or when the on / off of the heating means is completed, the heating means 2 is driven in step 46 to clear the timekeeping means 6 and to increase the temperature by 0.5.degree. Is measured (steps 48 and 49). During this time, the temperature detecting means 3
When a temperature drop of not less than ° C. is detected, the process returns to step 41 and restarts depending on whether the temperature at that time is equal to or higher than a predetermined temperature (step 47). Further, when a rise of 0.5 ° C. is detected in step 49, the value of the time counting means 6 at that time is stored in the storage means 7 (step 5).
0).

Next, in steps 51 to 54, the time measuring means 6 measures the time for raising the temperature by 0.5 ° C.
When the temperature rises by 0 ° C., the timed value is cleared, and the time to rise by 0.5 ° C. is started again. In the meantime, the value of the time stored in the storage means 7 is tripled and the time during the time counting by the time counting means 6 is continuously compared. When the value of the time counting means 6 becomes large, it is regarded as boiling, and the heating means 2 is turned off. (Step 5
6) It has a configuration. In the meantime, if the temperature detecting means 3 detects a temperature decrease of 3 ° C. or more, step 4
1 is started again (step 5).
2).

As described above, according to the third embodiment, when the temperature at the start of water heating is high, the reference value for boiling detection can be created without performing on-off heating.

In this embodiment, the heating means and the heat retaining means are turned on simultaneously as a heating means. However, the same effect can be obtained by using only a heating element for heating.

[0039]

As is clear from the description of the above embodiment, according to the present invention, the convection is stabilized by turning on / off the heating means for a predetermined time at the start of water heating, so that the reference value for boiling detection can be made stably. It is possible to reliably detect boiling.

Further, even if water is added in the middle of boiling water, the reference value for boiling detection is made again after the water temperature is stabilized, so that the boiling can be detected more reliably.

When the boiling water temperature is high, since the heating means is not turned on / off, a stable reference value for boiling detection can be made, and stable boiling detection can be performed.

From the above, it is possible to provide an easy-to-use, high-quality electric water heater.

[Brief description of the drawings]

FIG. 1 is a block diagram of an electric water heater according to a first 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 electric water heater.

FIG. 4 is a block diagram of an electric water heater according to a second embodiment of the present invention.

FIG. 5 is a flowchart showing the operation of the electric water heater.

FIG. 6 is a block diagram of an electric water heater according to a third embodiment of the present invention.

FIG. 7 is a flowchart showing the operation of the electric water heater.

FIG. 8 (a) is an explanatory diagram showing a relationship between a sensor of an electric water heater and water temperature, and FIG. 8 (b) is an explanatory diagram showing water temperature when water is added during water heating of the electric water heater.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container 2 Heating means 3 Temperature detecting means 4 Energizing means 5 ON / OFF means 6 Clocking means 7 Storage means 8 Boiling detecting means 9 Heating start means 10 Drop detecting means 11 Comparison means

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-35621 (JP, A) JP-A-3-1824 (JP, A) JP-A-2-255114 (JP, A) JP-A-62-162 120815 (JP, A) JP-A-3-7114 (JP, A) JP-A-2-271813 (JP, A) JP-A-3-77510 (JP, A) JP-A-63-315009 (JP, A) Japanese Patent Publication No. 2-38961 (JP, B2) (58) Fields surveyed (Int. Cl. ⁷ , DB name) A47J 27/21

Claims (4)

(57) [Claims] [1 claim: a container containing a liquid, a temperature detecting means for detecting a pre-SL solution temperature of a heating means for heating the pre-SL solution body, energizing means for energizing said heating means, a first predetermined Timer means for measuring and keeping clearing the rising time for each temperature range; storage means for storing the first predetermined temperature range rising time measured by the time measuring means; and a boiling detection means for stopping the larger and the heating means a certain fraction of the value of the storage means, said heating means is energized first predetermined time, and an on-off means you reenergize after stopping the second predetermined time, Start the kettle
The heating means is turned on and off by the on / off means.
Energize for a first predetermined time and then stop energizing for a second predetermined time
And then re-energize before the timing means and the storage means
An electric water heater that performs boiling detection by operating the boiling detection means . 2. A container for accommodating a liquid, and a temperature of the liquid.
Temperature detecting means for detecting, and heating means for heating the liquid
An energizing means for energizing the heating means, a first predetermined temperature
A timekeeping hand that keeps clearing and clearing the rising time for each degree
And the first predetermined temperature range measured by the timing means is increased.
Storage means for storing the time for
Time is greater than a certain percentage of the value in the storage means
Boiling detection means for stopping the heating means, and the heating
Means is energized for a first predetermined time, and after stopping for a second predetermined time
And an on / off means for re-energizing the battery.
When the detecting means detects that the temperature is below the predetermined temperature
Operate the on / off means and then re-energize
The timing means, the storage means, and the boiling detection means.
An electric water heater that operates to detect boiling. 3. A ratio of a temperature detected by a temperature detecting means to a predetermined temperature.
A comparator means for compare, boiling detection means and counting means and the storage means when the temperature of the temperature detecting means has detected a predetermined temperature or higher when the heating is started by the start of heating means
Performs boiling detected by operating a first predetermined time through the heating means by off means is lower than a predetermined temperature
Power, then stop power supply for the second predetermined time, then re-power up
After that, the timing means, the storage means, and the boiling detection
Clear screen boiling detected by operating the means according to claim 1 or 2, wherein the electric kettle. 4. A container for accommodating a liquid and a temperature of the liquid.
Temperature detecting means for detecting, and heating means for heating the liquid
An energizing means for energizing the heating means, a first predetermined temperature
A timekeeping hand that keeps clearing and clearing the rising time for each degree
And the first predetermined temperature range measured by the timing means is increased.
Storage means for storing the time for
Time is greater than a certain percentage of the value in the storage means
Boiling detection means for stopping the heating means, and the heating
Means is energized for a first predetermined time, and after stopping for a second predetermined time
ON / OFF means for re-energizing, and a temperature detected by the temperature detecting means.
Equipped with a drop detection means to detect a drop in liquid temperature depending on the temperature
The drop detecting means detects the temperature by the temperature detecting means .
When detecting that the detected temperature is lowered a second predetermined temperature range, the first predetermined said heating means by said on-off means
Energization for a second time, then stop energization for a second predetermined time, and then
After re-energizing, the timing means, the storage means, and the boiling detection means
It is operated to perform a boiling detecting electrical water heater.