JPH0712400A - Electric water heater - Google Patents

Abstract

PURPOSE:To prevent generation of inconveniences such as oil shortage by a method wherein, in a state that an abnormal operation of a first temperature sensor is detected by an abnormal operation detecting means, a water heating temperature is detected by a second temperature sensor during heating by a heater and also the abnormal operation of the first temperature sensor is displayed by a display means. CONSTITUTION:In an electric water heater, in a normal operation, a water heating temperature is detected by a first temperature sensor TH1 during heating by a heater 21, and the heating state of the heater 21 is controlled by a control means 24 based on the detected temperature. Temperature of remaining water is detected by a second temperature sensor TH2, and a remaining water amount in a water storing tank 14 is also detected. On the contrary, if an abnormal operation of the first temperature sensor TH1 is detected by an abnormal operation detecting means 24, the water heating temperature is detected by the second temperature sensor TH2 during the heating by the heater 21, and the heating state of the heater 21 is controlled by the control means 24 based on the detected temperature, and further the abnormal operation of the first temperature sensor TH1 is displayed by a display means 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a plurality of temperature sensors,
The present invention relates to an electric water heater provided with a means for detecting an abnormality of the temperature sensor.

[0002]

2. Description of the Related Art Conventionally, an electric water heater described in, for example, Japanese Utility Model Publication No. 4-7485 is known.

This electric water heater has a hot water storage tank whose longitudinal direction is the vertical direction. This hot water storage tank heats and heats normal temperature water supplied from a water pipe connected to the lower part by a heater arranged at the bottom to generate hot water by convection, and this hot water is stored in the upper part of the hot water storage tank. It is designed to be stored in a stratified form from the side. Further, a hot water supply pipe provided with a hot water supply plug is connected to the upper part of the hot water storage tank, and the hot water stored is supplied to a bathtub or the like via the hot water supply pipe.

In this hot water storage tank, a first temperature sensor is attached near the lower end and a second temperature sensor is attached near the upper end. The third temperature sensor is attached to the lower side of the second temperature sensor, and the fourth temperature sensor is attached to the lower side of the third temperature sensor. ing.

Each of these temperature sensors is composed of a thermistor or the like which changes its resistance value depending on the temperature, and is connected to a control device for controlling a heater for boiling and storing hot water by electric power in a predetermined time zone such as a midnight power time zone. Has been done. Further, this control device is adapted to detect the water temperature of each part of the hot water storage tank by the resistance value of each temperature sensor. The first temperature sensor has a wide detection range and high accuracy, and detects the boiling temperature of the hot water when the heater is energized, and at a time other than a predetermined time zone such as the midnight power time zone, The temperature of the water supplied from the water pipe is constantly detected. Also, the second
The fourth temperature sensor is adapted to detect the amount of remaining hot water by detecting the water temperature of each part of the hot water storage tank, or to measure the temperature of the hot water supplied through the hot water supply pipe.

In such a structure, the control means compares the measured water temperature with the hot water temperature control pattern stored in the internal memory in a predetermined time zone such as the midnight power time zone, and the boiling water is heated. Determine the raising temperature. Then, the control device energizes the heater and heats the heater until it is detected by the first temperature sensor that the boiling water reaches a predetermined boiling temperature.

When each temperature sensor is disconnected or short-circuited, the resistance value becomes 0 or a value close to infinity. Then, in a state where the resistance value of the first temperature sensor becomes 0 or a value close to infinity, the control device detects an abnormality of the first temperature sensor and stops heating of the heater to prevent boiling. At the same time, the abnormality of each temperature sensor is displayed on the display.

[0008]

However, in the case where the first temperature sensor has an abnormality when the power supply to the heater is constantly stopped in the state where the abnormality of the temperature sensor is detected as in the above-mentioned conventional technique, Even if the other temperature sensor is normal,
The heating of the heater is always stopped. Therefore, it is possible to prevent boiling and ensure safety, but by stopping heating of the heater, the basic operation of boiling is also stopped. It has the problem of causing inconvenience.

Particularly, in this kind of electric water heater, since the stored hot water boiled in a predetermined time zone such as a midnight power time zone is used in a time zone other than the predetermined time zone, it is not a stage of using hot water. There are times when you do not notice abnormally. Therefore, there is a problem that even if repairs are made immediately, the hot water is not boiled until the next predetermined time period, which causes great inconvenience to the user of the electric water heater.

The present invention has been made in view of the above points, and in an electric water heater provided with a plurality of temperature sensors,
An electric water heater that not only detects abnormalities in these temperature sensors, but also substitutes boiling detection with other temperature sensors for abnormalities in this temperature sensor to prevent inconvenience such as insufficient hot water volume. The purpose is to provide.

[0011]

The electric water heater of the present invention comprises:
Hot water storage tank provided with a heater, control means for controlling the heater, first and second temperature sensors for detecting the temperature of hot water in the hot water storage tank, and abnormality detection means for detecting abnormality of each temperature sensor And a display unit that displays an abnormal state of each of the temperature sensors detected by the abnormality detection unit, and the control unit normally causes the boiling of hot water by the first temperature sensor when the heater is heated. While detecting the temperature, the second temperature sensor detects the amount of remaining hot water, and the abnormality detecting means detects the abnormality of the first temperature sensor. The boiling temperature of the hot water is detected, and the abnormal state of the first temperature sensor is displayed on the display means.

[0012]

In the electric water heater of the present invention, in normal time,
When the heater is heated, the boiling temperature of the hot water is detected by the first temperature sensor, and the control means controls the heating state of the heater according to the detected temperature. Then, the temperature of the stored hot water is measured by the second temperature sensor to detect the amount of remaining hot water in the hot water storage tank. In the state where the abnormality detecting means detects the abnormality of the first temperature sensor, the second
The temperature sensor detects the boiling temperature of the hot water, the control means controls the heating state of the heater according to the detected temperature, and the display means displays the abnormal state of the first temperature sensor to display the first temperature. Encourage sensor inspection and repair.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of an embodiment of the electric water heater of the present invention will be described below with reference to the drawings.

In FIG. 2, reference numeral 11 denotes a casing of an electric water heater having a rectangular or cylindrical shape, and a heat insulating material is provided inside the casing 11.
A hot water storage tank 14 wrapped in 12 is stored. The hot water storage tank 14 has a substantially cylindrical shape with the vertical direction being the longitudinal direction and the upper and lower surfaces being substantially spherical. And hot water storage tank 14
In the vicinity of the lower end of the hot water storage tank 14 is connected directly to a water pipe (not shown) and is connected to a water supply pipe 16 for supplying tap water at room temperature to the hot water storage tank 14.
A drain pipe 17 equipped with a valve is connected so that hot water in the hot water storage tank 14 can be discharged as necessary. A hot water supply pipe 18 having a hot water tap is connected near the upper end of the hot water storage tank 14, and a hot water of a predetermined temperature is supplied to a bathtub or the like (not shown) through a mixing valve or the like.

Further, a heater 21 is arranged near the lower end of the hot water storage tank 14 so that the hot water in the hot water storage tank 14 can be heated. Is configured.

A control chamber 23 is provided on one side of the housing 11, and a control device 24 that also serves as a control unit and an abnormality detection unit is housed in the control chamber 23. This controller
24 is connected to a power line of an AC commercial power supply (not shown) via an earth leakage breaker 25, etc., and energizes the heater 21 at a specific time zone such as a midnight power time zone to convect hot water in the hot water storage tank 14. It is designed to be heated.

A remote control device 26 as a display means is connected to the control device 24. The remote control device 26 is provided with an operation unit for inputting instructions for various setting items, a display unit for displaying the operating state, etc., so that the control device 24 can be operated remotely.

Further, on the side surface of the hot water storage tank 14, a first temperature sensor TH1 is mounted near the water supply pipe 16 at the lower end, and a second temperature sensor TH2 is positioned near the upper end. Is attached. Further, a third temperature sensor TH3 is attached below the second temperature sensor TH2, and a fourth temperature sensor is attached below the third temperature sensor TH3. TH4 is installed.

Then, these temperature sensors TH1 to TH4
Are each composed of a thermistor or the like electrically connected to the control device 24, and change their resistance values according to the temperature of the hot water in the hot water storage tank 14. Then, the control device 24 can detect the temperature of the hot water at each height position in the hot water storage tank 14 by measuring these resistance values.

The first temperature sensor TH1 has a heater 21
At the time of energizing the, while detecting the boiling temperature of the hot water,
It detects the temperature of the water supplied from the water supply pipe 16, and has a wide detection range so that it can measure from a low temperature to a high temperature of about 90 ° C., and also includes a port for connecting the control device 24. , Those with high measurement accuracy are used.

Then, the second to fourth temperature sensors TH2
Through TH4, the control device 24 can determine the amount of hot water remaining in the stratified state by detecting the hot water temperature at each height position of the hot water storage tank 14. For example, when the fourth temperature sensor TH4 detects a water temperature equal to or higher than the predetermined temperature, the remaining hot water amount is 180 liters or more, the fourth temperature sensor TH4 is equal to or lower than the predetermined temperature, and the third temperature sensor TH3 is equal to or lower than the predetermined temperature. When the temperature is higher than the temperature, the amount of remaining hot water is 18
It is in the range of 0 to 120 liters, the third temperature sensor TH3 is below a predetermined temperature, and the second temperature sensor TH2
Is higher than the predetermined temperature, the remaining hot water amount is in the range of 120 to 60 liters, and when the second temperature sensor TH2 is lower than the predetermined temperature, it is determined that the remaining hot water amount is 60 liters or less.

The amount of remaining hot water measured by the second to fourth temperature sensors TH2 to TH4 is the remote control device.
The second temperature sensor TH2 has a function of measuring the temperature of hot water supplied through the hot water supply pipe 18 and a function of detecting boiling, which will be described later. Since it also has the above, the first temperature sensor TH1 having a high measurement accuracy is used next to the first temperature sensor TH1.

Further, the control device 24 is constantly operated by a control power source different from the midnight power, etc., and constitutes a so-called microcomputer controller, and determines the boiling temperature according to the feed water temperature or has a large amount of remaining hot water. In addition to having a CPU for performing so-called peak shift calculation for delaying the energization start time, various memories, etc.,
Time zone detection means, output control means, etc. are connected.
Then, this memory stores a plurality of control patterns of the boiling temperature according to the water supply temperature to the hot water storage tank 14, and determines the constantly detected water temperature information to the hot water storage tank 14 for the past several days. It is designed to be updated and stored as the water supply temperature. Further, the time zone detection means starts the operation when a timer switch is activated and power is turned on in a specific time zone such as the midnight power supply time zone, and sends the midnight power input information to the CPU. ing. Then, the output control means drives the power relay according to the instruction of the CPU to control the energization of the heater 21.

Next, the control operation by the controller 24 will be described with reference to FIG.
This will be described with reference to the flowchart in FIG.

First, the midnight power input information from the time zone detecting means is detected (step 1), and if there is the midnight power input information, it is judged whether or not the first temperature sensor TH1 is normal (step 2). . Here, if the resistance value of the first temperature sensor TH1 is within a predetermined range, the first temperature sensor TH1
, And the connection portion from the first temperature sensor TH1 to the CPU is judged to be normal, and if the resistance value of the first temperature sensor TH1 is outside the predetermined range, it is judged to be abnormal.

When it is determined that the first temperature sensor TH1 is normal, the water supply temperature is called from the above memory, or the hot water storage tank is directly measured by the first temperature sensor TH1.
The water supply temperature to 14 is detected (step 3), the hot water temperature control pattern is selected and read from the memory according to this water supply temperature and the remaining hot water amount and other information stored in the memory. The elevated temperature is determined (step 4). Then, the power control unit drives the power relay to start energizing the heater 21 (step 5).

In this state, the heater 21 is heated, and the hot and cold water in the entire hot water storage tank 14 is gradually heated and boiled while convection. The hot and cold water in the hot water storage tank 14 is, for example, in the case where there is no remaining hot water amount and the water temperature is 10 ° C., the power is about 8 hours and the set value of the control pattern is about 85.
Boil up to ℃. Then, when the first temperature sensor TH1 detects that the boiling water has reached the set boiling temperature (step 6), the heater 21 is deenergized (step 7).

Next, if it is determined in step 2 that the first temperature sensor TH1 is abnormal, the display of the remote controller 26 indicates that the first temperature sensor TH1 is abnormal (step 8). ), It is determined whether the second temperature sensor TH2 is normal (step 9).

It should be noted that the remote control device 26 has a first display on the display.
The lamp corresponding to the temperature sensor TH1 of 1 is blinked, or a display such as "E: 01" is displayed on the liquid crystal display.

If it is determined that the second temperature sensor TH2 is normal, the energization of the heater 21 is started regardless of the feed water temperature (step 10). Then, when the second temperature sensor TH2, instead of the first temperature sensor TH1, detects that the hot water reaches a predetermined boiling temperature set in advance (step 11), the heater 21 is energized. Stop (step 12).

On the other hand, if it is determined in step 9 that the second temperature sensor TH2 is abnormal, a message indicating that the second temperature sensor TH2 is abnormal is displayed on the display unit of the remote controller 26, if necessary. The power supply to the heater 21 is stopped (step 13).

As described above, according to this embodiment, when the first temperature sensor TH1 is determined to be normal, the boiling temperature of hot water is detected by the first temperature sensor TH1 when the heater 21 is heated. The controller 24 can control the energization of the heater 21 according to the detected temperature.

In addition, the second to fourth temperature sensors TH2 ...
With TH4, it is possible to measure the temperature of the hot water stored in the hot water storage tank 14 in a stratified form, and detect the amount of residual hot water in the hot water storage tank, and the peak shift calculation is performed as in the conventional case.

When the controller 24 detects an abnormality in the first temperature sensor TH1, the first temperature sensor TH1 is detected.
The second temperature sensor TH2, which has the second highest accuracy after 1, is used to detect the boiling temperature of the hot water when the heater 21 is heating,
The heating state of the heater 21 can be controlled according to the detected temperature. Therefore, even when the first temperature sensor TH1 has an abnormality, it is possible to prevent boiling and the like, and it is possible to ensure the basic function of boiling hot water of a predetermined temperature, thereby preventing inconvenience such as insufficient hot water. be able to.

Further, when the abnormality of the first temperature sensor TH1 is detected, the function of detecting the temperature of the water supplied to the hot water storage tank 14 is stopped, so it is desirable to inspect and repair it at an early stage. The remote controller 26 has a first temperature sensor TH
By displaying that 1 is abnormal, it is possible to prompt early inspection and repair of the first temperature sensor TH1.

When the abnormality of the first temperature sensor TH1 is detected and the second temperature sensor TH2 having the next highest accuracy is used next to the first temperature sensor TH1, the first temperature sensor TH1 is used.
By setting the setting temperature of the second temperature sensor TH2 a few degrees lower (eg 88 ° C) than the maximum setting temperature of TH1 (eg 90 ° C), the safety against boiling will be further ensured. You can also

In the embodiment shown in the flow chart of FIG. 1, when the abnormality of the first temperature sensor TH1 is detected in step 2 and the abnormality of the second temperature sensor TH2 is detected in step 9, , The power supply to the heater 21 was stopped (step 13), but the first and second
The third and fourth temperature sensors TH3 for measuring the amount of remaining hot water even when an abnormality is detected in the temperature sensors TH1 and TH2
, TH4 with a certain accuracy are used, the heaters can be used by using these temperature sensors TH3, TH4.
It is also possible to control the energization of 21.

That is, as shown in the flow chart of FIG. 3, when the abnormality of the second temperature sensor TH2 is detected in step 9, the second information is displayed on the display unit of the remote controller 26.
It indicates that the temperature sensor TH2 is abnormal (step 14) and determines whether the third temperature sensor TH3 is normal (step 15). Here, if the third temperature sensor TH3 is normal, the energization of the heater 21 is started (step 16). Thereafter, as in step 11 and thereafter, the boiling temperature of the hot and cold water is detected by the third temperature sensor TH3, and when the temperature reaches a predetermined temperature, the power supply to the heater 21 is stopped.

If it is determined in step 15 that the third temperature sensor TH3 is abnormal, it is displayed that the third temperature sensor TH3 is abnormal (step S15).
17) and it is judged whether the fourth temperature sensor TH4 is normal (step 18). Here, the fourth temperature sensor TH4
If is normal, the energization of the heater 21 is started (step 19). Thereafter, as in step 11 and thereafter, the boiling temperature of the hot and cold water is detected by the fourth temperature sensor TH4, and when the predetermined temperature is reached, the power supply to the heater 21 is stopped.

Further, if an abnormality of the fourth temperature sensor TH4 is detected in step 18, the fact that the fourth temperature sensor TH4 is abnormal is displayed (step 20), and the heater is displayed. Stop energizing 21.

Thus, the third and fourth temperature sensors
By controlling the energization of the heater 21 using TH3 and TH4, the user can operate the first and second temperature sensors TH1 and TH4.
Even if you do not notice the abnormality in 2 and do not request repair, etc., as long as one of the temperature sensors is normal, the basic function of boiling is automatically performed, and there is a shortage of hot water due to the sensor abnormality for the time being. Users are not inconvenienced.

[0042]

According to the electric water heater of the present invention, the boiling temperature of the hot water is detected by the first temperature sensor at the time of heating the heater at all times, and the control means determines the heating state of the heater according to the detected temperature. To control. Then, the temperature of the stored hot water can be measured by the second temperature sensor to detect the amount of remaining hot water in the hot water storage tank. Then, when the abnormality detecting means detects the abnormality of the first temperature sensor, the second temperature sensor, which is usually used for detecting the amount of remaining hot water during normal heating of the heater, is actuated so that the boiling water is heated. The temperature is detected, and the heating state of the heater is controlled by the controller according to the detected temperature. Therefore, even when the first temperature sensor has an abnormality, it is possible to boil hot water having a predetermined temperature and prevent inconvenience such as insufficient hot water amount. When an abnormality of the first temperature sensor is detected, the display unit displays the abnormal state of the first temperature sensor to check the first temperature sensor while the amount of hot water used for the time being can be secured. Since it is possible to prompt repairs, it is possible to use the bath without running out of water until the repairs are completed.

[Brief description of drawings]

FIG. 1 is a flow chart for explaining the operation of an embodiment of the electric water heater of the present invention.

FIG. 2 is a sectional view of the electric water heater.

FIG. 3 is a flow chart for explaining the operation of another embodiment of the electric water heater of the present invention.

[Explanation of symbols]

 14 Hot water storage tank 21 Heater 24 Control device also serving as control means and abnormality detection means 26 Remote control device as display means TH1 first temperature sensor TH2 second temperature sensor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Watanabe 2-2-7 Higashigotanda, Shinagawa-ku, Tokyo Osaki Electric Industry Co., Ltd.

Claims (1)

[Claims] 1. A hot water storage tank having a heater, control means for controlling the heater, first and second temperature sensors for detecting the temperature of hot water in the hot water storage tank, and an abnormality of each of the temperature sensors. An abnormality detection unit that detects the abnormality and a display unit that displays an abnormal state of each of the temperature sensors detected by the abnormality detection unit are provided, and the control unit normally includes the first temperature sensor when the heater is heated. Detects the boiling temperature of hot water by
With the second temperature sensor detecting the amount of remaining hot water, and the abnormality detecting means detecting the abnormality of the first temperature sensor, the boiling temperature of the hot water is detected by the second temperature sensor when the heater is heated. An electric water heater characterized by detecting and displaying an abnormal state of the first temperature sensor on the display means.