JP2000342453A - Electric water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the water level of a water storage container without making container structure complicated, without generating an insanitary water reservoir section, and also, without making the cleaning of the water storage container hard to perform, in an electric water heater. SOLUTION: This electric water heater has a water storage has a water storage container 2 which stores hot water, a heating means 4 which heats the hot water in the water storage container 2, water passing pipes 6 and 8 which discharge the hot water from the bottom section of the water storage container 2, and an electrically operated pump 7 for the hot water discharging, which is provided between the water passing pipes 6 and 8. In such an electric water heater, the water passing pipe 6 between the electrically operated pump 7 and the water storage container 2 is provided halfway with a pressure type water level sensor 11 which directly detects the head pressure of the water storage container 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a household electric water heater, and more particularly to water level detection of an electric electric water heater that discharges water by an electric pump.

[0002]

2. Description of the Related Art As an electric water heater used at home or the like, a water storage container for storing hot water, heating means for heating the hot water in the water storage container, a water pipe for taking out hot water from the bottom of the water storage container, and a water pipe There is known an electric electric water heater having a hot water supply electric pump provided in the middle of the water heater.

[0003] In the electric electric water heater described above, a water pressure corresponding to the water level of the water storage container is detected by a pressure sensor, and an output signal of the pressure sensor is used to display the water level (remaining hot water amount) of the water storage container. For example, in an electric water heater disclosed in Japanese Patent Application Laid-Open No. 10-257970, a pressure sensor is disposed at the bottom of a water storage container, and the head pressure of the water storage container is directly detected by the pressure sensor to store the water. The remaining hot water amount (hot water amount) of the container is displayed.

As another conventional example, Japanese Patent Application Laid-Open No.
As shown in Japanese Patent No. 29018 and Japanese Patent No. 2753074, a pressure guiding tube communicating with the bottom of the water reservoir at the lower end is provided, and a pressure sensor is attached to the closed upper end of the pressure guiding tube. In some cases, a water pressure corresponding to the water level of a water storage container is detected through an air layer formed in the upper part of the pressure guiding tube.

[0005]

Problems to be Solved by the Invention
The prior art as shown in Japanese Patent No. 70 can directly detect the head pressure of the water storage container, but separately from the outlet of the water pipe, an opening is provided at the bottom of the water storage container, Since the pressure sensor faces the opening, the structure of the container becomes complicated, an unsanitary pool is generated, and it becomes difficult to clean the water storage container.

In the apparatus disclosed in Japanese Patent Application Laid-Open No. Sho 62-129018 and Japanese Patent No. 273074, a pool is not generated, but the water level in the water storage container is adjusted via an air layer. Since the water pressure is detected, a detection error is likely to occur due to the compression of the air layer due to the water pressure, the mixing of hot water with air, and the like, and it is difficult to accurately display the water level of the water reservoir and the amount of remaining hot water.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and does not complicate the structure of the container, does not cause an unsanitary pool, and cleans the water storage container. It is an object of the present invention to provide an electric water heater capable of directly detecting the head pressure of a water storage container and accurately displaying the water level (remaining hot water amount) of the water storage container without making the operation difficult.

[0008]

In order to achieve the above object, an electric water heater according to the first aspect of the present invention comprises:
Electricity having a water storage container for storing hot water, heating means for heating the hot water in the water storage container, a water pipe for taking out hot water from the bottom of the water tank, and an electric pump for tapping water provided in the middle of the water pipe. In the water heater, a pressure type water level sensor is provided in the middle of a water pipe between the electric pump and the water storage container, and a change per unit time of an electric signal output from the pressure type water level sensor is controlled by the electric motor. When the value exceeds the specified value during operation of the pump,
The remaining amount of hot water in the water storage container is detected as zero.

According to a second aspect of the present invention, in the electric water heater, the pressure type water level sensor has a pressure receiving diaphragm which is exposed on one surface into a pipe of the water passage pipe, and the other surface side of the diaphragm. A permanent magnet attached to
A hall element that senses the magnetism of the permanent magnet and outputs an electric signal according to the pressure-receiving displacement of the diaphragm.

In the electric water heater according to the first aspect of the present invention, a pressure type water level sensor is provided in a middle part of a water pipe between the electric pump and the water storage container, that is, in a middle of a hot water passage (on the water storage container side with respect to the electric pump). The water level of the water reservoir is detected by detecting the water head pressure of the water reservoir acting on the water tank, and the change per unit time of the electric signal output from the pressure type water level sensor exceeds a predetermined value during the operation of the electric pump. At this time, it is detected that the remaining amount of hot water in the water storage container is zero.

In the electric water heater according to the second aspect of the present invention, the head pressure of the water storage container acts on one surface of the diaphragm exposed in the conduit of the water flow pipe, and the diaphragm is displaced by the head pressure due to the head pressure. The distance between the permanent magnet and the Hall element changes due to the pressure receiving displacement, and the Hall element outputs an electric signal according to the pressure receiving displacement of the diaphragm, that is, according to the head pressure of the water storage container.

[0012]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIGS. 1 to 4 show an embodiment of an electric water heater according to the present invention. An electric water heater is provided in a water storage container 2 that is stored in an outer container 1 and stores hot water.
And a lid 3 ′ provided on the shoulder 3 at the top of the outer container 1 so as to be openable and closable, and heating means 4 provided at the bottom of the water storage container 2, such as an electric heater for heating the water in the water storage container 2. Have.

A hot water outlet 5 is opened at the bottom of the water storage container 2, and one end of a water reservoir side (suction side) water pipe 6 in which the hot water outlet 5 is formed in a U shape by rubber or the like is connected. ing. The other end of the water reservoir side water pipe 6 is connected to a suction port 7a side of an electric pump 7 for tapping water. One end of a discharge-side water pipe 8 is connected to a discharge port 7 b of the electric pump 7. The other end of the discharge-side water pipe 8 is a downward tap hole 9.

The water reservoir side water pipe 6 has a U-shaped sensor connection port 10 which is open at the bottom, and a pressure type water level sensor 11 for detecting the head pressure (water level) of the water reservoir 2 at the sensor connection port 10. Is connected.

According to this sensor mounting structure, it is not necessary to provide an opening for the sensor in the water storage container 2 only by forming the hot water outlet 5 of the water storage tube side water pipe 6 in a U-shape.
The container structure of the water storage container 2 does not become complicated, an unsanitary pool is not generated, and the water storage container 2 can be easily cleaned.

A control unit 12 is disposed in the outer container 1, and switch buttons (not shown) of a tapping switch 13 and a reboiler switch 14 (see FIG. 6) and a water level of the water storage container 2 are provided on the shoulder 3. A display 15 such as a liquid crystal display for displaying (amount of remaining hot water) is provided.

As shown in FIG. 5, the pressure type water level sensor 11 has a mounting portion 20 for inserting the sensor connection port 10 and an introduction passage 21 communicating with the water pipe 6 on the reservoir side.
, A sensor case 23 fixed to the joint body 22, a joint body 22 and the sensor case 23
And a pressure-receiving diaphragm 24 that is exposed to the inside of the water storage container side water pipe 6 via the introduction passage 21 on one surface.

The pressure type water level sensor 11 has an electric magnet piece 26 mounted on the other surface side of the diaphragm 24 via a holding block 25 and an electric element mounted on the sensor case 23 and having a Hall element 27 mounted thereon. Wiring board 2
8, a rubber cap 29 for sealing the electric wiring board 28 from the outside of the sensor case 23, and a counter spring 31 provided between the adjustment screw member 30 screwed to the sensor case 23 and the holding block 25. are doing.

In the pressure type water level sensor 11, the water pressure in the pipeline of the water reservoir side water passage 6, in other words, the water head pressure acts on one surface of the diaphragm 24, and the water head pressure and the spring 3
The diaphragm 24 is displaced rightward in the figure according to the increase in the head pressure due to the equilibrium relationship with the opposing pressure by the pressure 1.

The Hall element 27 senses the magnetism of the permanent magnet piece 26 and outputs an electric signal corresponding to the distance from the permanent magnet piece 26. The Hall element 27 separates from the permanent magnet piece 26 by the displacement of the diaphragm 24. Since the distance changes, an electric signal corresponding to the pressure receiving displacement of the diaphragm 24, in other words, the water head pressure is output.

Thus, the pressure type water level sensor 11 directly detects the head pressure (water level) of the water storage container 2 including the inside of the water storage container side water pipe 6.

FIG. 6 shows a control system of the electric water heater. The control unit 12 includes a microcomputer 40
An input interface section 41 of the hot water switch 13 and the reboil switch 14; a heating circuit 4; a drive circuit 42 of the electric pump 7; And 15 drive circuits 44.

The microcomputer 40 controls the driving of the heating means 4 and the electric pump 7 according to the on / off state of the hot water switch 13 and the reboil switch 14, and the head of the water storage container 2 detected by the pressure type water level sensor 11. A display process of the remaining hot water amount by the display 15 is performed according to the pressure.

FIG. 1 shows a non-hot state (electric pump stopped state,
FIG. 2 shows a hot water supply state (water supply) by the electric pump 7, and the pressure type water level sensor 11 detects a water head pressure by the water level La of the water storage container 2 in the non-water supply state. In the state, the head pressure based on the water level Lb of the water storage container 2 is detected.

In this manner, the water level of the water storage container 2 proportional to the head pressure is accurately detected in both the non-hot water state and the hot water state, and the display of the remaining hot water amount in the water storage container 2 is made. It can always be performed accurately, including when the hot water is out.

As shown in FIG. 3, the hot water in the water storage container 2 is completely discharged by the electric pump 7, and the electric pump 7 is continuously driven thereafter. Hot water in the water pipe 6 is also sucked out, and finally, as shown in FIG. 3, the inside of the water pipe 6 is almost empty, and the pressure type water level sensor 11 detects the atmospheric pressure. Thereby, the output of the pressure type water level sensor 11 at the time of the atmospheric pressure can be obtained.

Thereafter, when the electric pump 7 is turned off,
As shown in FIG. 4, the hot water remaining in the discharge side water pipe 8 returns to the water storage vessel side water pipe 6.

FIG. 7 shows the output characteristics of the pressure type water level sensor 11 when full discharge is performed from the full state, and then atmospheric pressure sensing is performed.

By the above-described operation, the microcomputer 40 can take in the sensor output at the time of the atmospheric pressure, and generate an empty signal indicating zero water quantity by the sensor output when the electric pump is turned off (when the remaining hot water returns). The setting can be made on the microcomputer 40 side so as to output.

Thus, even if there is a variation (individual difference) in the output value of the pressure type water level sensor 11 at the atmospheric pressure, zero water amount can be accurately detected.

[0032]

As will be understood from the above description, according to the electric water heater according to the first aspect of the present invention, a water storage container for storing hot water, heating means for heating the water in the water storage container, and the water storage container An electric water heater having a water pipe for taking out hot water from the bottom of the water pipe and an electric pump for tapping water provided in the middle of the water pipe, wherein a pressure type water level is provided in the water pipe between the electric pump and the water storage container. A sensor is provided, and when a change per unit time of an electric signal output from the pressure type water level sensor exceeds a predetermined value during operation of the electric pump, the remaining amount of hot water in the water storage container becomes zero. Was detected.

For this reason, the head pressure of the water storage container is detected by the pressure type water level sensor on the water storage container side of the electric pump in the middle of the hot water supply passage, and the water level of the water storage container proportional to the water head pressure is detected at the time of tapping. If the remaining amount of hot water in the water reservoir becomes zero during the operation of the electric pump, the change per unit time of the electric signal output from the pressure type water level sensor exceeds a predetermined value, This accurately detects that the remaining amount of hot and cold water in the water storage container is zero,
It is possible to always accurately display the amount of remaining hot water in the water storage container including the state of the hot water.

Further, depending on the position of the pressure type water level sensor, the pressure type water level sensor detects the atmospheric pressure when hot water in the water pipe on the water storage container side is drawn from the electric pump. Even if the output value at the time of the atmospheric pressure fluctuates, zero water amount can be accurately detected.

According to the electric water heater according to the second aspect of the present invention, the pressure type water level sensor includes a pressure receiving diaphragm that is exposed in one side of the water passage pipe.
It is constituted by a permanent magnet attached to the other surface side of the diaphragm, and a Hall element that senses the magnetism of the permanent magnet and outputs an electric signal according to a pressure-receiving displacement of the diaphragm.

Therefore, the head pressure of the water reservoir acts on one surface of the diaphragm exposed in the conduit of the water pipe,
Due to this head pressure, the diaphragm undergoes pressure displacement, the distance between the permanent magnet and the Hall element changes due to this pressure displacement, and an electric signal corresponding to the water head pressure of the water storage container is output,
Based on the head pressure of the water storage container, the water level of the water storage container is accurately detected including the time of tapping, and the remaining hot water amount of the water storage container can always be accurately displayed including the time of tapping.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of an electric water heater according to the present invention in a non-hot state.

FIG. 2 is a cross-sectional view showing one embodiment of the electric water heater according to the present invention in a tapping state.

FIG. 3 is a sectional view showing one embodiment of the electric water heater according to the present invention in a full discharge state.

FIG. 4 is a cross-sectional view showing one embodiment of the electric water heater according to the present invention when the electric pump is off after full discharge.

FIG. 5 is a detailed sectional view showing a specific example of a pressure type water level sensor used in the electric water heater according to the present invention.

FIG. 6 is a block diagram showing a control system of the electric water heater according to the present invention.

FIG. 7 is a graph showing sensor output characteristics at the time of tapping of the electric kettle according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer container 2 Water storage container 3 'Lid 4 Heating means 5 Hot water outlet 6 Water storage container side water pipe 7 Electric pump 8 Discharge side water pipe 9 Water outlet 10 Sensor connection port 11 Pressure type water level sensor 12 Control unit 15 Display 22 Joint body 23 Sensor case 24 Diaphragm 26 Permanent magnet piece 27 Hall element 28 Electric wiring board 31 Counter spring 40 Microcomputer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tetsuya Ikeda 1-20-5 Tenma, Kita-ku, Osaka-shi, Osaka Elephant-in-Mahobin Co., Ltd. (72) Inventor Shuji Wakato 1-20, Tenma, Kita-ku, Osaka, Osaka No.5 Elephant In-House Mahobin Co., Ltd. (72) Inventor Masao Futami 1311 Aobadai, Tokorozawa-shi, Saitama Seisakusho Co., Ltd. F-term in Tokorozawa Office (reference) 4B055 AA34 BA07 BA42 CA01 CA64 CA69 CA71 CB13 CC01 CC17 CC28 CC33 CC38 CD01 CD15 CD44 CD61 GA04 GB15 GC36

Claims (2)

[Claims] 1. A water storage container for storing hot water, a heating means for heating the hot water in the water storage container, a water pipe for taking out the water from the bottom of the water storage container, and an electric tap for water supply provided in the middle of the water pipe. In an electric water heater having a pump, a pressure type water level sensor is provided in the middle of a water pipe between the electric pump and the water storage container, and an electric signal output from the pressure type water level sensor per unit time. When the change exceeds a predetermined value during operation of the electric pump, the remaining amount of hot water in the water storage container is detected to be zero. 2. The pressure type water level sensor according to claim 1, wherein said pressure-type water level sensor includes a pressure-receiving diaphragm that is exposed in one side of said water pipe, a permanent magnet attached to the other surface of said diaphragm, and a permanent magnet. 2. The electric water heater according to claim 1, further comprising a Hall element that senses the magnetism of a magnet and outputs an electric signal according to a pressure-receiving displacement of the diaphragm.