JP5396986B2 - Electric water heater - Google Patents

Description

  The present invention relates to an electric water heater that heats and keeps water in a container.

  Conventionally, this type of electric water heater has been configured as shown in FIG. 3 (see, for example, Patent Document 1). Hereinafter, the configuration will be described.

  FIG. 3 is a cross-sectional view of a conventional electric water heater. As shown in FIG. 3, a container 1 of a conventional electric water heater contains water, and a heating means (here, a heater) 2 is attached to the bottom of the container 1. A first temperature sensor 3 for detecting the water temperature is attached to the center of the bottom of the container 1. The lid part 4 is attached to the container body 16 by a hinge (not shown) so as to be freely opened and closed.

  The control unit 5 is equipped with an electronic circuit such as a microcomputer, and controls energization to the heating means 2 so as to perform a water heating operation.

  When the user presses the reheating key 6, the water in the container 1 is heated again by the heating means 2.

  The operation of the conventional electric water heater configured as described above will be described.

  When the user puts water into the container 1 and starts energization, the control unit 5 starts energizing the heating means 2. By energization, the heating means 2 generates heat, and the water temperature in the container 1 rises. When the temperature detected by the first temperature sensor 3 is 100 ° C. or higher and the water has boiled, the control unit 5 stops energizing the heating means 2.

  After that, the heat retaining operation is performed, and the control unit 5 energizes the heating means 2 so that the temperature detected by the first temperature sensor 3 maintains the heat retaining temperature. When the user presses the reheating key 6 during the heat insulation, the control unit 5 receives it and energizes the heating means 2, and the water in the container 1 boils again.

JP-A-6-343553

  However, in such a configuration of the conventional electric water heater, every time the user presses the reheating key 6, the water in the container 1 boils and becomes steam and diffuses into the air, resulting in power loss. It was.

  Further, in order to eliminate this power loss, if the energization of the heating means 2 is stopped before boiling, the variation of the first temperature sensor 3 is about 4 ° C. in terms of temperature. Therefore, there is a problem that the temperature setting must be lowered, and the temperature of water when the energization to the heating means 2 is stopped has a variation of about 4 ° C.

  The present invention solves the above-described conventional problems. In a reheating operation performed each time the user presses the reheating key 6, the heating means 2 is energized until just before boiling, and the heating means 2 immediately before boiling. An object of the present invention is to provide an electric water heater with less power loss by stopping energization.

In order to solve the above-described conventional problems, an electric water heater of the present invention includes a container for storing water, a heating means for heating the container, a first temperature sensor installed at the bottom of the container, and the container A steam passage installed at the top of the steam passage, a second temperature sensor installed in the steam passage, and a boiling detection means for detecting a temperature rise of the second temperature sensor and stopping energization of the heating means. Time measuring means for starting time measurement after the boiling detection means detects boiling; temperature storage means for storing the detected temperature of the first temperature sensor when the time measuring means measures a predetermined set time; Reheating key for reheating, temperature increasing means for energizing the heating means when the reheating key is pressed, and temperature correction value for storing temperature correction values determined by the characteristics of the container and the heating means Storage means, KiNoboru raising means, until the temperature detected by the first temperature sensor rises to a temperature value obtained by adding the stored temperature correction value to the temperature correction value storage means stored temperature to the temperature memory means, The heating means is energized. In the reheating operation started by the user pressing the reheat key during the heat retention, the heating means is energized until just before the water in the container boils. In addition, it is possible to reduce power loss due to boiling by stopping energization of the heating means immediately before boiling.

  The electric water heater of the present invention is capable of energizing the heating means until the water in the container is boiled in the reheating operation started by the user pressing the reheating key during the heat insulation, By stopping energization of the heating means immediately before, the loss of electric power due to boiling can be reduced.

The system block diagram of the electric water heater in Embodiment 1 of this invention Temperature graph of the electric water heater Sectional view of a conventional electric water heater

The present invention includes a container for containing water, a heating means for heating the container, a first temperature sensor installed at the bottom of the container, a steam passage installed at the top of the container, and the steam passage A second temperature sensor installed in the apparatus, a boiling detection means for detecting an increase in temperature of the second temperature sensor to stop energization of the heating means, and a time measurement after the boiling detection means detects boiling. Timing means for starting the operation, temperature storage means for storing the temperature detected by the first temperature sensor when the timing means measures a predetermined set time, a reheating key for reheating, and the reheating A temperature raising means for energizing the heating means when the key is pressed, and a temperature correction value storage means for storing a temperature correction value determined by the characteristics of the container and the heating means, the temperature raising means, sensing the temperature of the first temperature sensor is Until raised to a temperature value obtained by adding the stored temperature correction value to the temperature correction value storage means stored temperature to the temperature memory means, characterized in that energizing the heating means, in thermal insulation In the reheating operation started by the user pressing the reheating key, the heating means can be energized until just before the water in the container boils, and the energization to the heating means is stopped immediately before boiling. Thus, it is possible to reduce power loss due to boiling.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a system configuration diagram of an electric water heater according to Embodiment 1 of the present invention, and FIG. 2 is a temperature graph of the electric water heater. In addition, the same code | symbol is attached | subjected to the same part as the said conventional electric water heater, and the description is abbreviate | omitted.

In FIG. 1, a steam passage 7 is provided at the upper part of the container 1 of the electric water heater in the present embodiment.
Is installed, and the steam generated in the container 1 is released to the outside of the lid 4. A second temperature sensor 8 is installed in the steam passage 7 to detect the temperature of the steam passing through the steam passage 7. The boiling detection means 9 detects the boiling by detecting the temperature rise rate or the absolute temperature of the second temperature sensor 8 and stops energization of the heating means 2.

  In the present embodiment, when the temperature rise of the second temperature sensor 8 rises by 2 ° C. per second, or when the absolute temperature of the second temperature sensor 8 exceeds 90 ° C., it is regarded as boiling. The time counting means 10 starts time counting when the boiling detection means 9 detects boiling, and the temperature storage means 11 stores the temperature detected by the first temperature sensor 3 after the time setting means 10 has passed a predetermined set time. To do. In the present embodiment, the set time is one and is 10 minutes.

  When the user presses the reheating key 6, the temperature raising means 12 stores the temperature detected by the first temperature sensor 3 in the temperature correction value storage means 13 to the temperature value stored in the temperature storage means 11. The heating means 2 is energized until it rises to a temperature value to which the temperature correction value (here 1 ° C.) is added. The heat retaining means 14 is heated so that the first temperature sensor 3 maintains the heat retaining temperature (for example, about 95 ° C.) after the boiling detecting means 9 detects boiling and stops energization of the heating means 2. The means 2 is energized intermittently.

  The boiling detection means 9, the timing means 10, the temperature storage means 11, the temperature raising means 12, the temperature correction value storage means 13, and the heat retention means 14 are the program in the microcomputer mounted on the control unit 5, and the periphery of the microcomputer It is realized by a circuit.

  The operation of the electric water heater in the present embodiment configured as described above will be described. When water is introduced into the container 1 and a commercial power source is connected, energization of the heating means 2 is started, and gradually the container 1 The water inside is heated and eventually boils. When the water in the container 1 boils, steam rises from the water surface and is released into the atmosphere through the steam passage 7.

  At this time, the detected temperature of the second temperature sensor 8 installed in the steam passage 7 rises, and as described above, the rising speed is 2 ° C. or more per second or the detected temperature of the second temperature sensor 8. When the angle exceeds 90 degrees, it is regarded as boiling, and the boiling detection means 9 stops energization of the heating means 2. At the same time that the boiling detecting means 9 detects boiling, the time measuring means 10 starts measuring time, and when the time exceeds the set time (10 minutes), the temperature storage means 11 records the temperature of the first temperature sensor 3. To do.

  After the boiling detecting means 9 detects boiling, the heat retaining means 14 performs intermittent energization of the heating means 2 so that the temperature detected by the first temperature sensor 3 becomes the heat retaining temperature (95 ° C. in this case). The water in 1 is kept at a temperature of about 97 ° C. When the user presses the reheating key 6 in this state, the temperature raising means 12 starts energizing the heating means 2 and the water temperature in the container 1 rises.

  When the temperature detected by the first temperature sensor 3 reaches a temperature value obtained by adding the temperature correction value (1 ° C.) stored by the temperature correction value storage means 13 to the temperature value stored in the temperature storage means 11, The temperature raising means 12 stops energization to the heating means 2.

  FIG. 2 is a graph of the detected temperatures of the first temperature sensor 3 and the second temperature sensor 8 when the amount of water in the container 1 is large and small.

  In this graph, the detected temperature curve 20 of the first temperature sensor 3 when the amount of water is large, the detected temperature curve 21 of the second temperature sensor 8, and the detection of the first temperature sensor 3 when the amount of water is small. They are a temperature curve 22 and a detected temperature curve 23 of the second temperature sensor 8. The temperature detected by the second temperature sensor 8 rapidly increases after the steam passes through the steam passage 7.

  When the amount of water is large, the boiling detection means 9 stops energization of the heating means 2 at the point 24 where the temperature detected by the second temperature sensor 8 suddenly rises, and when the amount of water is small, the second temperature sensor 8. At a point 25 where the detected temperature rapidly rises, the boiling detection means 9 stops energization of the heating means 2.

  At this time, the temperature 26 of the first temperature sensor 3 after a set time (after 10 minutes) from the point 24 when the amount of water is large, and the set time (after 10 minutes) from the point 25 when the amount of water is small. The temperature 27 of the first temperature sensor 3 has a characteristic that becomes a substantially constant value regardless of the amount of water. This is because the amount of radiant heat from the heating means 2 to the first temperature sensor 3 is large when the amount of water is large because the heating time is long, and when the amount of water is small, the heating time is short and small, but the influence is set. This is because by appropriately taking the time, the temperature substantially disappears after the set time (here, 10 minutes) and follows the water temperature in the container 1.

  The temperature storage means 11 stores the detected temperature of the first temperature sensor 3 after this set time (after 10 minutes).

  The temperature sensor originally has a variation of about 4 ° C in the detected temperature, and if the temperature setting at a temperature close to the boiling temperature is not less than or equal to 95 ° C, it will exceed the boiling temperature due to the variation of the temperature sensor. There is a possibility.

  However, according to the present embodiment, the temperature storage unit 11 stores the detected temperature of the first temperature sensor 3 after a set time (10 minutes later) from the boiling point, thereby canceling the variation of the temperature sensor. The temperature close to the boiling point can be set.

  A temperature value obtained by adding the temperature correction value (1 ° C.) stored in the temperature correction value storage unit 13 to the temperature value stored in the temperature storage unit 11 is used as the temperature increase unit 12 to energize the heating unit 2. By setting the temperature to end, the variation of the first temperature sensor 3 is offset, and the energization to the heating means 2 can be stopped at the temperature just before the water in the container 1 boils.

  The temperature correction value stored in the temperature correction value storage unit 13 determines a timely value based on the characteristics of the container 1 and the heating unit 2 (here, 1 ° C.). At the time of reheating, the energization time of the heating means 2 is short and the influence of radiant heat from the heating means 2 to the first temperature sensor 3 is small, so there is almost no difference in the water temperature after the end of reheating due to the amount of water.

  As described above, the electric water heater according to the present invention energizes the heating means until the water in the container is boiled in the reheating operation started by the user pressing the reheat key during the heat retention. In addition, it is possible to reduce power loss due to boiling by stopping energization of the heating means immediately before boiling.

DESCRIPTION OF SYMBOLS 1 Container 2 Heating means 3 1st temperature sensor 4 Cover part 5 Control unit 6 Reheating key 7 Steam passage 8 2nd temperature sensor 9 Boiling detection means 10 Time measuring means 11 Temperature memory means 12 Temperature rising means 13 Temperature correction value memory | storage Means 14 Thermal insulation means

Claims (1)

A container for containing water, a heating means for heating the container, a first temperature sensor installed at the bottom of the container, a steam passage installed at the top of the container, and installed in the steam passage A second temperature sensor; a boiling detection means for detecting a temperature rise of the second temperature sensor to stop energization of the heating means; and a timing for starting timing after the boiling detection means detects boiling. Means, temperature storage means for storing the temperature detected by the first temperature sensor when the time measuring means measures a predetermined set time, a reheating key for reheating, and the reheating key being pressed. A heating means for energizing the heating means, and a temperature correction value storage means for storing a temperature correction value determined by the characteristics of the container and the heating means ,
It said heating means until the temperature detected by the first temperature sensor rises to a temperature value obtained by adding the stored temperature correction value to the temperature correction value storage means stored temperature to the temperature memory means, electric kettle was characterized by energizing the heating means.

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