JP3712892B2 - Electric water heater - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric water heater for home use, and more particularly to detection of a water level of an electric electric water heater that discharges hot water with an electric pump.
[0002]
[Prior art]
As an electric water heater used at home, etc., 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 extracting hot water from the bottom of the water storage container, and provided in the middle of the water pipe An electric electric water heater having an electric pump for hot water is known.
[0003]
In the electric electric water heater as described above, the water pressure corresponding to the water level of the water storage container is detected by the pressure sensor, and the water level (remaining hot water amount) of the water storage container is displayed using the output signal of the pressure sensor. 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 pressure of the water storage container is directly detected by this pressure sensor so that the remaining water in the water storage container can be detected. The amount of hot water (the amount of hot water) is displayed.
[0004]
As another conventional example, as shown in Japanese Patent Application Laid-Open No. Sho 62-129018 and Japanese Patent No. 2753074, a pressure guiding pipe communicating with the bottom of the water storage container is provided at the lower end, and the pressure guiding pipe is provided. There is also a type in which a pressure sensor is attached to the upper end of the closed tube and the water pressure corresponding to the water level of the water storage container is detected by an air layer formed in the upper part of the pressure guiding tube by the pressure sensor.
[0005]
[Problems to be solved by the invention]
The conventional one shown in Japanese Patent Laid-Open No. 10-257970 can directly detect the water head pressure of the water storage container, but it is opened at the bottom of the water storage container separately from the outlet of the water pipe. Since the opening is provided with a pressure sensor facing the opening, the container structure becomes complicated, an unsanitary water reservoir is generated, and the water storage container is difficult to clean.
[0006]
In the ones disclosed in Japanese Patent Application Laid-Open No. 62-129018 and Japanese Patent No. 273074, a water reservoir is not generated, but the water pressure corresponding to the water level of the water storage container is detected through the air layer. For this reason, detection errors are likely to occur due to compression of the air layer due to water pressure, air mixing into hot water, etc., and it is difficult to accurately display the water level of the water storage container and the amount of remaining hot water.
[0007]
The present invention has been made to solve the above-described problems, does not complicate the container structure, does not produce an unsanitary water reservoir, and is difficult to clean the water storage container. It is an object of the present invention to provide an electric water heater that can directly detect the water head pressure of a water storage container and accurately display the water level (remaining hot water amount) of the water storage container without making it.
[0008]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, an electric water heater according to the first aspect of the present invention comprises a water storage container for storing hot water, a heating means for heating the hot water in the water storage container, and hot water from the bottom of the water storage container. In an electric water heater having a water pipe and an electric pump for hot water provided in the middle of the water pipe, a pressure-type water level sensor is provided in the middle of the water pipe between the electric pump and the water storage container, When the change per unit time of the electrical 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 is detected to be zero.
[0009]
In the electric water heater according to the second aspect of the present invention, the pressure-type water level sensor is attached to a pressure receiving diaphragm that is exposed in the conduit of the water conduit on one surface, and the other surface side of the diaphragm. The permanent magnet and a Hall element that senses the magnetism of the permanent magnet and outputs an electrical signal corresponding to the pressure-receiving displacement of the diaphragm.
[0010]
In the electric water heater according to the first aspect of the invention, it acts on the pressure type water level sensor in the middle part of the water pipe between the electric pump and the water storage container, that is, in the middle of the hot water passage (the water storage container side from the electric pump). By detecting the water head pressure of the water storage container, the water level of the water storage container is detected, and when the change per unit time of the electric signal output from this pressure type water level sensor exceeds a predetermined value during operation of the electric pump, It is detected that the remaining amount of hot water in the water storage container is zero.
[0011]
In the electric water heater according to the second aspect of the invention, the water head pressure of the water storage container acts on one surface of the diaphragm exposed in the conduit of the water pipe, and the diaphragm receives and displaces the pressure by the water head pressure. The distance between the permanent magnet and the Hall element changes due to the displacement, and the Hall element outputs an electrical signal corresponding to the pressure-receiving displacement of the diaphragm, that is, the water head pressure of the water storage container.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
[0013]
1 to 4 show an embodiment of an electric water heater according to the present invention. The electric water heater is provided at the bottom of the water storage container 2, a water storage container 2 that is stored in the outer container 1 and stores hot water, a lid 3 ′ that can be opened and closed on the shoulder 3 at the top of the outer container 1, and the water storage container 2. And a heating means 4 such as an electric heater for heating the hot water in the water storage container 2.
[0014]
A hot water outlet 5 is opened at the bottom of the water storage container 2, and one end of a water storage container 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. The other end of the water storage container side water pipe 6 is connected to the suction port 7a side of the electric pump 7 for hot water. One end of a discharge side water pipe 8 is connected to the discharge port 7 b of the electric pump 7. The other end of the discharge side water pipe 8 is a downward hot water outlet 9.
[0015]
The water reservoir side water pipe 6 has a sensor connection port 10 opened at the bottom of the U-shape, and a pressure type water level sensor 11 for detecting the water head pressure (water level) of the water reservoir 2 is connected to the sensor connection port 10. ing.
[0016]
According to this sensor mounting structure, it is only necessary to form the hot water outlet 5 of the water storage container side water pipe 6 in a U shape, and it is not necessary to provide an opening for the sensor in the water storage container 2. The structure is not complicated, unsanitary water reservoirs are not generated, and the water storage container 2 can be easily cleaned.
[0017]
Further, a control unit 12 is disposed in the outer container 1, and switch buttons (not shown) of the hot water switch 13 and the reboiling switch 14 (see FIG. 6) and the water level (remaining hot water) of the water storage container 2 are disposed on the shoulder body 3. A liquid crystal display 15 for displaying the amount of water is provided.
[0018]
As shown in FIG. 5, the pressure-type water level sensor 11 includes a joint body 22 having an attachment portion 20 for fitting the sensor connection port 10 and an introduction passage 21 communicating with the water storage vessel side water pipe 6, A sensor case 23 fixed to the joint body 22, is sandwiched between the joint body 22 and the sensor case 23, and is attached to the inside of the joint body 22 and the sensor case 23. And a pressure-receiving diaphragm 24 exposed in the road.
[0019]
The pressure-type water level sensor 11 includes a permanent magnet piece 26 attached to the other surface side of the diaphragm 24 via a holding block 25, and an electric wiring board 28 attached to the sensor case 23 and mounted with a hall element 27. And a rubber cap 29 that seals 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. ing.
[0020]
In this pressure type water level sensor 11, the water pressure in the conduit of the water storage vessel side water pipe 6, in other words, the water head pressure acts on one surface of the diaphragm 24, and the water head pressure and the counter pressure by the counter spring 31 are balanced. Due to the relationship, the diaphragm 24 is displaced to the right in the figure as the water head pressure increases.
[0021]
The hall element 27 detects the magnetism of the permanent magnet piece 26 and outputs an electrical signal corresponding to the distance from the permanent magnet piece 26, and the distance from the permanent magnet piece 26 is changed by the displacement of the diaphragm 24. Therefore, an electric signal corresponding to the pressure-receiving displacement of the diaphragm 24, in other words, the water head pressure is output.
[0022]
Thereby, the pressure type water level sensor 11 directly detects the water head pressure (water level) of the water storage container 2 including the inside of the water storage container side water pipe 6.
[0023]
FIG. 6 shows a control system of the electric water heater. The control unit 12 includes a microcomputer 40, an input interface 41 of the hot water switch 13 and a reboiling switch 14, a heating means 4, a drive circuit 42 for the electric pump 7, and an A for taking in the signal of the pressure type water level sensor 11. A / D converter 43 and a drive circuit 44 for the display 15 are provided.
[0024]
The microcomputer 40 controls the drive of the heating means 4 and the electric pump 7 according to the on / off of the hot water switch 13 and the reboiling switch 14, and according to the head pressure of the water storage container 2 detected by the pressure type water level sensor 11. Then, the display 15 displays the amount of remaining hot water.
[0025]
FIG. 1 shows a non-hot water state (electric pump stopped state, non-flowing water), and FIG. 2 shows a hot water discharge state (passing water) by the electric pump 7, and the pressure-type water level sensor 11 The water head pressure due to the water level La of 2 is detected, and the water head pressure due to the water level Lb of the water storage container 2 is detected in the hot water state.
[0026]
As a result, the water level of the water storage container 2 that is proportional to the water head pressure is accurately detected regardless of whether it is in the non-hot water state or the hot water state, and the remaining hot water amount in the water storage container 2 is displayed in the hot water state. Can always be done accurately.
[0027]
As shown in FIG. 3, when all the hot water in the water storage container 2 is discharged by the electric pump 7, the electric pump 7 continues to be driven. The hot water in the inside is also sucked out, and finally, as shown in FIG. 3, the inside of the water storage vessel side water pipe 6 becomes almost empty, and the pressure type water level sensor 11 senses the atmospheric pressure. Thereby, the output of the pressure type water level sensor 11 at atmospheric pressure can be obtained.
[0028]
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 container side water pipe 6.
[0029]
FIG. 7 shows the output characteristics of the pressure type water level sensor 11 when full discharge is performed from the full state and the atmospheric pressure is detected thereafter.
[0030]
By the operation as described above, the microcomputer 40 can take in the sensor output at the atmospheric pressure, and outputs an empty signal indicating zero water amount by the sensor output when the electric pump is turned off (returning the remaining hot water). It can be set on the microcomputer 40 side.
[0031]
Thereby, even if there is variation (individual difference) in the output value of the pressure type water level sensor 11 at the atmospheric pressure, it is possible to accurately detect zero water amount.
[0032]
【The invention's effect】
As 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, a heating means for heating the hot water in the water storage container, and hot water from the bottom of the water storage container. In an electric water heater having a water pipe to be taken out and an electric pump for hot water provided in the middle of the water pipe, a pressure-type water level sensor is provided in the middle of the water pipe between the electric pump and the water storage container. And when the change per unit time of the 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 is detected as zero. did.
[0033]
For this reason, the head pressure of the water storage container is detected by the pressure-type water level sensor on the side of the water storage container from the electric pump in the middle of the hot water passage, and the water level of the water storage container that is proportional to the water head pressure is accurately detected including when the hot water is discharged. In addition, if the remaining amount of hot water in the water storage container becomes zero during the operation of the electric pump, the change per unit time of the electrical signal output from the pressure type water level sensor exceeds the predetermined value. It is possible to accurately detect that the remaining amount of hot water in the container is zero, and display the amount of remaining hot water in the water storage container accurately at all times including when the hot water is discharged.
[0034]
Also, depending on the position of the pressure type water level sensor, when hot water in the water pipe on the water storage container side is sucked out from the electric pump, the pressure type water level sensor detects the atmospheric pressure. Even if the output value varies, it is possible to accurately detect zero water amount.
[0035]
According to the electric water heater of the second aspect of the present invention, the pressure-type water level sensor is disposed on one surface of the diaphragm for pressure reception that is exposed in the conduit of the water conduit, and on the other surface side of the diaphragm. It is assumed that it is composed of an attached permanent magnet and a Hall element that senses the magnetism of the permanent magnet and outputs an electrical signal corresponding to the pressure-receiving displacement of the diaphragm.
[0036]
For this reason, the water head pressure of the water storage container acts on one surface of the diaphragm exposed in the conduit of the water conduit, and the diaphragm receives and displaces due to this water head pressure, and this pressure displacement causes the distance between the permanent magnet and the Hall element. Changes, and an electrical signal corresponding to the water head pressure of the water storage container is output, and the water level of the water storage container is accurately detected from the water head pressure of the water storage container, including at the time of hot water discharge. It becomes possible to display the amount of water accurately always including the time of the hot water.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of an electric water heater according to the present invention in a non-hot water state.
FIG. 2 is a cross-sectional view showing one embodiment of the electric water heater according to the present invention in terms of the state of discharged water.
FIG. 3 is a sectional view showing one embodiment of an electric water heater according to the present invention in a full discharge state.
FIG. 4 is a sectional view showing one embodiment of the electric water heater according to the present invention in a state when the electric pump is turned off after full discharge.
FIG. 5 is a detailed sectional view showing a specific example of a pressure-type water level sensor used in an electric water heater according to the present invention.
FIG. 6 is a block diagram showing a control system of an electric water heater according to the present invention.
FIG. 7 is a graph showing sensor output characteristics at the time of tapping with an electric water heater according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Outer container 2 Water storage container 3 'Cover body 4 Heating means 5 Hot water outlet 6 Water storage container side water pipe 7 Electric pump 8 Discharge side water pipe 9 Hot water outlet 10 Sensor connection port 11 Pressure type water level sensor 12 Control unit 15 Indicator 22 Joint body 23 Sensor case 24 Diaphragm 26 Permanent magnet piece 27 Hall element 28 Electric wiring board 31 Counter spring 40 Microcomputer

Claims (2)

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 extracting hot water from the bottom of the water storage container, and an electric pump for hot 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 the water pipe between the electric pump and the water storage container;
When the change per unit time of the electrical 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 is detected to be zero.
Electric water heater characterized by that. The pressure-type water level sensor senses a pressure-receiving diaphragm exposed on one side of the conduit of the water conduit, a permanent magnet attached to the other side of the diaphragm, and the magnetism of the permanent magnet. The electric water heater according to claim 1, wherein the electric water heater is configured by a Hall element that outputs an electric signal corresponding to the pressure-receiving displacement of the diaphragm.

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