JPH06209852A - Electric hot-water heater - Google Patents

Abstract

PURPOSE:To obtain an electric hot-water heater which can detect exactly boiling-up by detecting boiling-up in a short time. CONSTITUTION:In the electric hot-water heater provided with a boiling-up sensor 12 for detecting boiling-up of a liquid, a hot water temperature sensor 5 for detecting a temperature of the liquid, and a controller 15 for controlling an output of a heating element 4 from hot water heating to warming, when the boiling-up sensor 12 detects boiling-up, the controller 15 stores a temperature of the boiling-up sensor 12, when a temperature of the liquid detected by the hot water temperature sensor 5 reaches a prescribed temperature, decides it to be boiling-up when the boiling-up sensor 12 rises to a prescribed temperature, based on this stored temperature as a reference, and controls an output of the heating element 4 from hot water heating to warming.

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 water to detect boiling properly.

[0002]

2. Description of the Related Art Conventionally, in an electric water heater equipped with a sensor for boiling detection in addition to a water temperature sensor for detecting the temperature of liquid in a container, it is judged to be boiling when the temperature of the boiling sensor itself reaches a predetermined temperature, and the water is boiled. The heater was not energized.

[0003]

In the above-mentioned conventional example, since it was determined that the boiling sensor itself was boiling when the temperature of the boiling sensor itself reached a predetermined temperature, the temperature of the boiling sensor itself was determined to be the predetermined temperature from the start of energization for boiling detection. Since it took a long time to reach, the temperature of the boiling sensor attached to the lid was easily affected by the surrounding environment (temperature, etc.).

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a container for containing a liquid, a lid provided on the upper part of the container, and a liquid in the container are heated. A heating element, a boiling sensor installed near the lid to detect boiling of the liquid, a water temperature sensor installed in the container to detect the temperature of the liquid, and when the boiling sensor detects boiling, heat is maintained from boiling In the electric water heater having a controller for controlling the output of the heating element, the controller is
When the temperature of the liquid detected by the hot water temperature sensor reaches a predetermined temperature, the temperature of the boiling sensor is memorized, and based on this memorized temperature, it is judged as boiling when the boiling sensor rises a predetermined temperature, The output of the heating element was controlled to keep warm.

[0005]

With the above configuration, the boiling detection is performed within a short time after the hot water temperature sensor reaches the predetermined temperature and before the boiling sensor shows the predetermined temperature rise. ) Is less affected, and more accurate boiling detection can be performed.

[0006]

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

In the figure, 1 is the body of an electric water heater, and 2 is
Is a container for containing a liquid 3 such as water, and is contained in the main body 1. Reference numeral 4 denotes a heating element, which is composed of a high-output water heater 16 and a low-output heat-retaining heater 17, which are connected in parallel with the power source 19 and are mounted on the bottom surface of the container 2 to heat the liquid 3 in the container 2. , To keep warm. A hot water temperature sensor 5 is attached to the center of the bottom surface of the container 2.
Reference numeral 6 denotes a lid, and a back lid 7 is attached to the lower side thereof, and a back lid cover 8 is attached and fixed to the lower surface of the back lid 7 and is provided in the upper opening of the main body 1 so as to be openable and closable. Reference numeral 9 denotes a steam port provided on the rear upper surface of the lid body 6, and the steam pipe 9 is provided at the steam port 9.
0 and the inner plug 11 are connected to form a steam passage. 1
Reference numeral 2 denotes a boiling sensor, which is installed in the vicinity of the steam packing 14 in the main body ring 13 provided above the main body 1 or the lid 6.

Reference numeral 15 denotes a controller composed of a microcomputer (hereinafter referred to as a microcomputer). The heating element 4, the hot water temperature sensor 5, and the boiling sensor 12 are used to control the entire electric water heater.
Etc. are connected. A thermal fuse 18 is connected between the power source 19 and the heater 16 for boiling the heating element 4. Reference numeral 20 denotes an opening / closing element composed of a triac, which is provided between the power source 19 and the heat-retaining heater 17, and the trigger terminal 20-1 is connected to the output terminal of the microcomputer 15.

Next, the operation of this embodiment having the above structure will be described.

Water 3 which is a liquid is put in a container 2 and a lid 6 is provided.
When the power is closed and the power is turned on, the microcomputer 15 uses the information from the hot water temperature sensor 5 to turn on the water heater 16 of the heating element 4,
Start boiling water.

After that, the water temperature in the container 2 gradually rises,
Along with that, a hot water temperature sensor 5 attached to the bottom of the container 2
When the temperature rises and reaches a predetermined temperature, the microcomputer 15 starts boiling detection.

First, the microcomputer 15 confirms that the temperature of the hot water temperature sensor 5 has reached a predetermined temperature (for example, 90 ° C.) and stores the temperature (T ° C.) of the boiling sensor 12 at that time. Then, when the water temperature further rises and reaches the boiling range, steam is discharged from the steam port 9 of the lid body 6 through the steam passages of the back cover 8, the inner plug 11 and the steam pipe 10. Steam pipe 1
The rear part of 0 is the body ring 13 through the steam packing 14.
Since it is in contact with the rear thin portion, the temperature of the boiling sensor 12 rises. In this state, when the temperature of the boiling sensor 12 rises by a predetermined temperature (for example, 10 ° C.) with reference to the temperature (T ° C.) stored in the microcomputer 15, the microcomputer 15
Determines that it is boiling, outputs a “closed” signal to the triac 20, and energizes the heat retaining heater 17 of the heating element 4. Then, the water heater 16 is not energized, and the heating element 4 is controlled to have a low output. After that, the microcomputer 15
The triac 20 is opened / closed based on the information from the hot water temperature sensor 5 to control the heat retention heater 17 to keep the liquid at a constant temperature (for example, 93 to 98 ° C.).

Therefore, in the electric water heater of the present invention, the boiling sensor 12 can detect boiling in a short time after the temperature sensor 5 reaches a predetermined temperature until the boiling sensor 12 shows a predetermined temperature rise. , Less affected by the surrounding environment (temperature, etc.).

[0014]

As described above, in the electric water heater of the present invention, the boiling sensor detects boiling within a short period of time until the boiling sensor shows a predetermined temperature rise after the hot water temperature sensor reaches a predetermined temperature. The temperature of is less affected by the surrounding environment (air temperature, etc.), and more accurate boiling detection can be performed.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an electric water heater showing an embodiment of the present invention.

FIG. 2 is a control circuit diagram for boiling detection of an electric water heater showing an embodiment of the present invention.

FIG. 3 is a flowchart of boiling detection of an electric water heater showing an embodiment of the present invention.

[Explanation of symbols]

 2 Container 4 Heating element 5 Hot water temperature sensor 6 Lid 12 Boiling sensor 15 Controller (microcomputer)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuaki Yamamoto, 3-3 Shinjuyoji, Kashiwa-shi, Chiba, Japan 1 Hitate Home Tech Co., Ltd. (72) Koji Yamauchi, 1-3 Shinjuyomi, Kashiwa-shi, Chiba, Japan 1 Standing Home Tech

Claims (1)

[Claims] 1. A container (2) for containing a liquid, a lid (6) provided on the upper part of the container (2), a heating element (4) for heating the liquid in the container (2), Boiling sensor (12) installed near the lid (6) to detect boiling of liquid
When the boiling temperature sensor (12) provided in the container (2) for detecting the temperature of the liquid and the boiling sensor (12) detect boiling, the output of the heating element (4) is controlled to keep the temperature from boiling. In the electric water heater equipped with a controller (15), the controller (15) controls the temperature of the boiling sensor (12) when the temperature of the liquid detected by the hot water temperature sensor (5) reaches a predetermined temperature. Is stored, and when the boiling sensor (12) rises to a predetermined temperature based on the stored temperature, it is judged to be boiling, and the output of the heating element (4) is controlled from boiling to keeping warm. Electric water heater.