JPS6345811B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electric water heater that cuts off electricity to a heating element after reliably boiling water.

Structure of conventional example and its problems In general, it is preferable that the hot water used for brewing tea, coffee, or black tea be boiled without any limescale or carbon dioxide gas.

Conventionally, in this type of electric water heater, a heat-sensitive element such as a thermostat that senses the water temperature is operated at a temperature below the boiling point of the water (for example, 93°C) to heat the water and raise the temperature. Since electricity was cut off, the water could not be boiled, and sufficient water sterilization and descaling effects could not be obtained.

In other words, since there are always variations in the operating temperature of the thermosensor, even if the operating temperature is set close to the boiling point of water, the thermosensor will not operate even though the water is boiling, and the temperature will increase. Because there are some substances that can cause a dangerous situation of continuous boiling due to continuous electricity supply to the body, the operating temperature of the thermosensor should be set to 93°C as described above.
The above-mentioned danger was avoided by setting the device to operate when the temperature reached approximately ℃.

Therefore, such electric water heaters have the disadvantage that they cannot sufficiently sterilize or descal water.

Therefore, as a solution to these drawbacks, the first method is
There is a boiling type electric water heater as shown in the block diagram in the figure.

To explain its configuration, it is equipped with a heat-sensitive element 1 that operates at a temperature below the boiling point of water, and a delay device 2 that stops power supply to the heater 3 after a certain period of time has elapsed from the operation of this heat-sensitive element 1. It becomes possible to stop energizing the heater 3 after boiling the water reliably.

However, in this boiling type water heater, the heater 3
Since the configuration is such that the power supply to the boiler is stopped, the boiling time varies depending on the amount of water to be boiled, and the smaller the amount of water to be boiled, the longer the boiling time becomes, which increases the danger. Moreover, when it is desired to boil the water again after a while after the power supply to the heater 3 is once stopped, the power supply to the heater 3 will not be performed unless the temperature of the heat-sensitive element 1 is lowered to a predetermined temperature by adding water. Therefore, it is not only complicated, but also has the drawback of consuming extra power because the added water must also be heated.

Purpose of the Invention The present invention solves these conventional problems.The present invention cuts off the electricity to the heating element after boiling the water reliably, and once the water has boiled and the water boiling is completed, the heating element is turned off. Even after the power supply is stopped,
To provide an electric water heater which can re-boil water by simply turning on a switch and can interrupt boiling at will.

Structure of the Invention In order to achieve the above object, an electric water heater of the present invention includes a heating element that heats a liquid, a temperature sensing element that detects the vapor temperature of the liquid, and a temperature of the temperature sensing element that reaches a predetermined value. a detection device that outputs a detection signal when the detection signal is reached; an energization device that stops energizing the heating body based on the detection signal of the detection device; an energization switch that arbitrarily starts the operation of the energization device; According to this configuration, even after the temperature sensing element reaches a predetermined temperature with liquid vapor and the electricity to the heating element is cut off, the energization switch can be turned on. By doing so, it is possible to energize the heating element again to re-boil the liquid, and by turning on the stop switch, the energization to the heating element can be quickly stopped.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

In FIGS. 2 and 3, reference numeral 11 denotes a cylindrical outer container body, which has a spout 12 fixed to its upper opening and a bottom plate 13 integrally attached to its lower end.

14 is a handle rotatably attached to the spout 12. Reference numeral 15 denotes an upper lid which covers spout 12 so as to be openable and closable, and this upper lid 15 is configured to be openable and closable by means of lock knobs 16 provided on both sides of front beak portion 15b using back portion 15a as a fulcrum. In addition, a cylindrical portion 15c with an opening on the top surface is provided in the center of the upper lid 15, and a push plate 1 that is vertically slidable is provided in the cylindrical portion 15c.
It has 7. 18 is a lock ring that restricts the vertical sliding of the push plate 17;
is engaged with the switching lever 19, and the push plate 1
7 vertical movements can be selected.

Reference numeral 20 denotes a bellows pump provided at the lower part of the push plate 17, and its upper end opening is fixed to the upper plate 21, and its lower end opening is fixed to the lid cover 22 by ultrasonic welding or the like to seal the pump. Further, the center part of the upper plate 21 has a ventilation hole 21a, and this ventilation hole 21
a is closed by a movable valve 24 that operates at the lower end of a push rib 23a provided at the center of the steam cover 23 integrally engaged with the push plate 17 when the push plate 17 moves downward; is configured to open the vent 21a when the push plate 17 moves upward. Further, a return coil spring 25 of the bellows pump 20 is interposed between the movable valve 24 and the inner bottom portion 22a of the lid cover 22. Reference numeral 22b is a spout provided approximately at the center of the inner bottom portion 22a, and the bellows pump 20 is connected to the spout 22b.
It communicates with a discharge port 27a of a lid body 27 made of synthetic resin via a lid gasket 26 attached to the lower part of the lid body 27.

Reference numeral 28 denotes a communication gasket that airtightly connects the vent hole 21a provided in the upper plate 21 and the steam cover 23, and the steam cover 23 and the steam hole 15d provided in the upper lid 15 are connected by a communication pipe 29.
Reference numeral 30 denotes a bottomed cylindrical container installed inside the container outer body 11, which has a flange portion 30a at its upper end, and is supported by the spout 12 via a container packing 31. Further, the lid 27 placed on the top surface of the container 30 has a discharge port 2 in the center thereof for discharging steam.
7a, and a valve chamber 33 with a built-in overflow prevention valve 32.
have. Further, a shielding plate 34 made of a stainless steel plate or the like is fixed to the lower surface of the lid 27 by screwing. A compartment A is formed by this shielding plate 34 and the lid 27.

35 is waterproof packing, this waterproof packing 35
keeps the container 30 and the lid 27 airtight. 3
Reference numeral 6 denotes a water rising pipe extending from the valve chamber 33 to the bottom of the container 30, and this water rising pipe 36 has its upper end extended to the outside of the container 30, and its tip is a spout opening downward. Outlet pipe 37 with 37a
The valve chamber 33 is connected to the valve chamber 33 via a valve cover 38. 39 is a ventilation hole having a substantially L-shaped passage provided at the bottom of the shielding plate 34, and 34a is a drip hole having a diameter smaller than that of the ventilation hole 39.

40 is a mounting tube made of polysulfon resin or the like provided in the upper part of the container 30, and this mounting tube 40 is
It is attached to the container 30 in a watertight manner with the ring 41, the attachment spring 42, and the attachment plate 43, and the shielding plate 34
It is in communication with the compartment A through a through hole 34b bored therein.

Reference numeral 44 denotes a temperature sensing element made of a thermistor having a negative temperature coefficient. It is thermally attached to a sensing cover 48 that is watertightly attached to the tip, and is fixed with a holder 49 and a holding cover 50.

Reference numeral 51 denotes a display frame fixed to the outer shell 11 of the container, and a water guide pipe 52 is provided approximately in the center of the display frame for guiding the hot water coming out of the spout 37a to the outside of the container. 53
is the water level gauge window.

Reference numeral 54 denotes a band-shaped heating device wrapped around the outer peripheral surface of the lower part of the container 30, in which a heating element 55 that generates a large amount of heat and an auxiliary heating element 56 that generates a small amount of heat are integrated. The temperature of the water stored in the container 30 is approximately 93°C on the outer peripheral surface of the container 30 near the top of this heating device 54.
A thermostat 57 for boiling water that operates when the temperature reaches ℃, and a safety thermostat 58 for preventing dry boiling.
is installed.

59 is a thermal reed switch that controls the energization of the auxiliary heating element 56 and maintains the water temperature at approximately 95°C; 60
is a temperature fuse, and this temperature fuse 60 and the thermal reed switch 59 are connected to a presser spring 6.
1 is pressed and held on the bottom surface of the container 30.

The electrical connections among the heating element 55, auxiliary heating element 56, water boiling thermostat 57, safety thermostat 58, thermal reed switch 59, and temperature fuse 60 are as shown in FIG.

Reference numeral 62 denotes a control board disposed below the bottom of the container 30. The circuit configuration of each electronic component attached to this control board 62 will be described below with reference to FIG. 4.

63 is a detection device, and this detection device 63 is a resistor 6.
The voltage V _x divided by the resistor 64 and the temperature sensing element 44 is inputted to one input terminal of the first comparator 67, and the comparison A voltage V r corresponding to a predetermined temperature T _r (80 to 90 degrees Celsius) of the temperature sensing element 44 is applied to the + input terminal of the device 67 through resistors 65 and 66, and a DC voltage V _cc is applied to the + input terminal of the device 67 _.
is input by dividing the pressure.

68 is an energizing device, and this energizing device 68 is connected to the resistor 6.
9, 70, a transfer contact type relay 71, and an NPN type transistor 72. _Vcc is divided by the resistors 69, 70, and this voltage dividing point (this point is referred to as point C) is connected to the transistor 72. is connected to the base terminal of the relay 71, the normally closed contact NC of the relay 71, and the output terminal of the first comparator 67.
The emitter terminal of the transistor 72 is connected to GND,
The collector terminals are each connected to one end of the coil of relay 71, and the other end of the coil of relay 71 is connected to _Vcc . Further, the common contact COM of the relay 71 is connected to GND, and the normally open contact NO is connected to the connection point between the heating element 55 and the water boiling thermostat 57, respectively.

Reference numeral 73 denotes an energization switch for arbitrarily starting the operation of the energization device 68, one end of which is connected to GND, and the other end connected to the collector terminal of the transistor 72.

Further, 74 is a stop switch that arbitrarily stops the operation of the energizing device 68, one end of which is connected to GND.
The other ends are connected to the base terminals of the transistors 72, respectively, and the energizing switch 73 and the stop switch 74 are attached to the container outer body 11 and face outward from the bottom of the display frame 51.

Note that 75 is an electrical connector clamped and fixed between the container outer shell 11 and the bottom plate 13, and 76 is a back plate that closes the lower opening of the bottom plate 13.

The operation of the above configuration will be explained with reference to FIGS. 3 to 5.

First, water is poured into the container 30 so that it does not reach the mounting tube 40, and when the power is turned on, the heating device 54
Powered by By supplying power to the heating device 54, the water in the container 30 is heated, and the water temperature rises as shown by the solid line in FIG. On the other hand, the water surface and the shielding plate 34
As shown by the dashed line, the temperature of the container space B and the compartment A, which are formed by the above, rises more slowly than the water temperature. In addition, the temperature sensing element 4 provided in the mounting tube 40
Since the temperature of No. 4 is transmitted through compartment A, it remains at an even lower temperature. At this time, when the energizing switch 73 is pressed, current flows through the coil of the relay 71, and the common contact COM and the normally open contact NO are connected. In addition, since the temperature of the temperature sensing element 44 is low, its resistance value is large, and therefore V _x <V _r .
The output of the comparator 67 becomes "H" and the transistor 72 is turned on, so that the relay 71 maintains the state in which current flows through the coil, that is, the "ON" state.

As the water temperature rises over time and reaches approximately 93°C, the water boiling thermostat 57 is activated.
Although it is in the OFF state, the relay 71 is connected to the heating element 55.
Current is continued through the normally open contact NO and the common contact COM, and the water temperature further increases.

On the other hand, when electricity is supplied to the auxiliary heating element 56, the water temperature is approximately 95°C.
When this happens, the thermal reed switch 59 is activated to cut off the current.

By energizing the heating element 55, the water temperature rises to about 95
When the temperature reaches approximately 1°C (at time t ₁ ), a rather large amount of steam begins to come out, and the temperature in container space B becomes close to the water temperature.
However, only weak steam enters into the compartment A through the ventilation hole 39, and therefore this steam is discharged from the discharge port 27a and is separated by the shielding plate 34, so that the steam inside the compartment A is The temperature rises relatively slowly. Of course, the temperature sensing element 44 is located in compartment A.
is maintained at an even lower temperature.

When the water temperature reaches the boiling point (t ₂ hours), a large amount of steam is suddenly generated and fills the container space B.
Then, it fills the compartment A through the ventilation hole 39 and rapidly raises the temperature. At the same time, compartment A and through hole 3
Steam also enters the mounting tube 40 that communicates with the temperature sensor 4b, causing the temperature sensing element 44 to rapidly rise in temperature and instantly exceed the predetermined temperature (T _r °C), so that V _x > V _r
Therefore, the output of the comparator 67 becomes "L" and the transistor 72 is turned off. As a result, the relay 71 enters the "OFF" state, the common contact COM is connected to the normally closed contact NC, and the power to the heating element 55 is cut off. (At time t ₃ ) That is, after the water has been reliably boiled, it is possible to stop supplying electricity to the heating element 55. In addition, the temperature of the temperature sensing element 44 is rapidly raised due to the sudden and large amount of steam generated by boiling of water, and the power to the heating element 55 is cut off, so a constant boiling time can be obtained regardless of the amount of water. .

After the power supply to the heating element 55 is cut off, the water temperature is maintained at approximately 95° C. by the auxiliary heating element 56 and the thermal reed switch 59. Therefore, a large amount of steam is no longer generated, and the compartment A and the temperature sensing element 44 are
temperature drops below the water temperature. Here, temperature sensing element 4
When the temperature of the relay 71 becomes lower than T _r ℃, the output of the comparator 67 becomes "H" and tries to turn on the transistor 72, but the common contact COM and the normally closed contact NC connected to the GND of the relay 71 are disconnected. Since the transistor 72 is connected, the transistor 72 remains OFF, and therefore the heating element 55 is not energized.

When the temperature of the temperature sensing element 44 falls below T _r ℃, press the energization switch 73 again (at time t ₄ ).
Similarly to the above explanation, the relay 71 is kept in the "ON" state, the heating element 55 is energized, the water is boiled again (at time t ₅ ), and a large amount of steam is generated again, which heats the temperature sensing element 44. After rapidly raising the temperature, the power to the heating element 55 is cut off. (At time t ₆ ) Furthermore, if the stop switch 74 is pressed while the water temperature is rising, the transistor 74 will be forcibly turned off, and as a result, the relay 71 will be in the "OFF" state.
Since the common contact COM and the normally closed contact NC of the relay 71 are connected, and the transistor 72 is kept OFF thereafter regardless of the output of the first comparator 67, it is possible to stop the boiling operation at will.

FIG. 6 shows a circuit configuration of another embodiment of the present invention, which differs from the previously described embodiment in that a timer device 75 is interposed between the detection device 63 and the energizing device 68. This timer device 75 is activated by a detection signal from the detection device 63, and outputs a energization stop signal to the energization device 68 after a predetermined set time has elapsed.The boiling time of the liquid can be arbitrarily set by the function of this timer device 75. It becomes possible.

Next, its configuration and operation will be described with reference to FIGS. 6 and 7, with only the differences from the previously described embodiments.

The timer device 75 includes a charging/discharging capacitor 76,
It is composed of a charging resistor 77, a charging/discharging resistor 78, voltage dividing resistors 79 and 80, a variable resistor 81 for boiling time adjustment, and a second comparator 82 of an open collector output type. 76+
The terminal, one end of the charging/discharging resistor 78, and one end of the voltage dividing resistor 79 are connected to _Vcc , and the negative pole of the capacitor and the other end of the charging/discharging resistor 78 are connected to one end of the charging resistor 77. and is connected to the + input terminal of the second comparator 82. (The potential at this point is _V1 .) The other end of the charging resistor 77 is connected to the output terminal of the first comparator 67 of the detection device 63. In addition, the voltage dividing resistor 7
The other end of 9 is connected to GND via variable resistor 81.
connected to another voltage dividing resistor 80 connected to
The connection point between the voltage dividing resistor 80 and the variable resistor 81 is input to one input terminal of the second comparator 82 . (The potential at this point is V ₂ .) The output terminal of the second comparator 82 is connected to point C of the energizing device 68 .

Next, the operation will be explained with reference to FIG. 7.

When water is poured into the container 30 and the power is turned on, power is supplied to the heating device 54 and the water is heated. When the energization switch 73 is turned on when the water temperature is low (at time t ₇ ), since V _x < V _r , the first comparator 67
The output of is "H", therefore the capacitor 7
No charging current flows through the second comparator 82, the potential of _V1 is kept at _Vcc , and since _V1 > _V2 , the second comparator 82
The output becomes "H", and transistor 72 and relay 71 are turned on.

When the water starts to boil (at time t ₈ ), the temperature sensing element 4
The temperature in step 4 also rises rapidly, and when it reaches the predetermined temperature (T _r °C) (at time t ₉ ), V _x > V _r .
The output of the comparator 67 becomes "L", and the _timer device 75 connects the capacitor 76 and resistor 77,
Current flows through 78 and charges the capacitor 76,
Its output voltage V ₁ is connected to capacitor 76 and resistor 7
7, 78, the voltage gradually decreases with the charging time constant determined by voltage dividing resistors 79, 80 and variable resistor 8.
1, the output of the second comparator ₈₂ becomes "L" and the relay 71 is activated.
The heating element 55 is turned off, and the power to the heating element 55 is cut off. (at time _t10 ) That is, by changing the potential of _V2 with the variable resistor 81, _V1 changes to V from the time ( _t9 ) when the temperature of the temperature sensing element 44 exceeds the predetermined temperature (T _r °C). Since the time until the time point (t ₁₀ ) becomes equal to ₂ can be adjusted, the boiling time of water can be easily adjusted. Further, it goes without saying that the water boiling time set by the variable resistor 81 is constant regardless of the amount of water, similar to what was explained in the above embodiment.

Note that if the stop switch 74 is pressed while the water is boiling, the power to the heating element 55 is cut off, and boiling can be stopped at will, as in the above-mentioned embodiment.

Effects of the Invention As is clear from the above explanation, the electric water heater of the present invention uses a temperature-sensitive element that detects the steam temperature to control the energization of the heating element. In addition, it is possible to cut off the power supply to the heating element after boiling for a certain period of time, and by providing an energization switch that starts the operation of the energization device at will, it is possible to easily re-boil even when the liquid is kept warm. .

Further, since a stop switch is provided to arbitrarily stop the operation of the energizing device, boiling can be easily stopped, and as a result, it is very easy to use.

[Brief explanation of drawings]

Fig. 1 is a system block diagram showing a conventional boiling type electric water heater, Fig. 2 is a perspective view of an electric water heater showing an embodiment of the present invention, and Fig. 3 is a longitudinal cross-section of the electric water heater. The top view, Figure 4 is the electric circuit diagram of the electric water heater,
Fig. 5 is a temperature-time characteristic diagram of each part of the electric water heater, Fig. 6 is an electric circuit diagram of the electric water heater showing another embodiment of the present invention, and Fig. 7 is a diagram of the electric water heater. FIG. 4 is a time characteristic diagram showing the temperature of each part and the operation of the circuit. 44... Temperature sensing element, 55... Heating body, 63...
Detection device, 68... Energizing device, 73... Energizing switch, 74... Stop switch, 75... Timer device.

Claims (1)

[Scope of Claims] 1. A heating element that heats a liquid, a temperature sensing element that detects the vapor temperature of the liquid, and a detection device that outputs a detection signal when the temperature of the temperature sensing element reaches a predetermined value. An energization device that stops energizing the heating body in response to a detection signal from the detection device, an energization switch that arbitrarily starts the operation of the energization device, and a stop switch that arbitrarily stops the operation of the energization device. Electric water heater. 2. The electric water heater according to claim 1, further comprising a timer device that is activated by a detection signal from the detection device and outputs a energization stop signal to the energization device after a predetermined period of time has elapsed.