JP3192922B2 - an electronic pot - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric pot in which hot water is heated by induction heating.

[0002]

2. Description of the Related Art In general, an electric pot includes a heat-insulating main body having an inner container for accommodating water (hot water) and a resistance heating wire for heating water in the inner container. It is provided with. Further, a tapping mechanism for tapping manually with an electric pump or using air pressure is provided at an upper portion of the main body. In this case, this kind of electric pot is provided as a dedicated one for boiling water and keeping the temperature of the hot water.

As one of the cooking utensils, a desktop type induction heating cooker (electromagnetic cooker) for home use has been provided. This is configured to include a high-frequency power supply unit and a heating coil in a main body, and performs induction cooking of an iron pan or the like placed on a top plate on the upper surface of the main body to heat and cook boiled foods and fried foods. Things.

[0004] In recent years, a so-called handy type container (water kettle) for boiling water has been provided as an accessory to this type of induction heating cooker for home use in recent years. This kettle container is made of a metal and has a substantially cylindrical shape. A pouring spout is integrally formed on the peripheral surface of the container, and a handle is attached to the opposite side of the spout. Hot water is poured from the spout by holding the hand and tilting it.

[0005]

However, the conventional water heater container provided as an accessory of the induction heating cooker is different from a general electric pot for exclusive use and is used like a small-sized medical can. It was not designed to keep the temperature of the heated water even after the heating was stopped. For this reason, if you want to keep the boiling water warm, the user must transfer the water to another warming pot, etc., so it can not be so convenient, even if it is attached to the induction heating cooker In fact, it was not used effectively. Also, in this kettle container,
It was difficult to use because the bath had to be tilted out of the bath by hand and the outer surface became hot.

[0006] Therefore, the outer wall of the above-mentioned water heater container is made into a double structure, a closed space is formed on the outer peripheral surface of the inner container, and a heat insulation structure is employed in which the space is evacuated to thereby keep the heat insulating. It is conceivable to provide a function. However, in this case, in order to withstand a vacuum, both of the double walls generally need to be made of metal such as iron.In this case, when the hot water is boiled by induction heating, the inner wall and the inner wall are also guided to the outer wall side. It will generate heat by heating,
There is a possibility that the energy efficiency is reduced and the outer wall is thermally deformed.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electric kettle in which hot water is boiled by induction heating, and which can ensure good heat retention. is there.

[0008]

An electric pot according to the present invention comprises:
An induction heating section having a high-frequency power supply section and a heating coil in the main body, and a pot section detachably mounted on a top plate on the upper surface of the main body of the induction heating section, wherein the pot section includes An inner container configured from a metal conductive material in a bottomed container shape and containing water, an insulating wall portion provided to surround a peripheral wall of the inner container, and a hot water supply mechanism provided at an upper portion of the inner container. And the heat insulating wall portion is
Of the inner container so as to form a closed space between the inner container and the inner container.
An outer wall made of a metal plate is provided on the outer periphery,
The present invention is characterized in that the lower end of the outer wall is located above the bottom of the inner container (the invention of claim 1).

In this case, the inside of the closed space of the heat insulating wall can be configured in a reduced pressure state (the invention of claim 2).
Alternatively , a heat insulating material such as glass wool may be provided in the closed space of the heat insulating wall (the invention of claim 3). Further, in these cases, it is more effective if the pressure in the closed space of the heat insulating wall is about 0.1 Torr (the invention of claim 4).

[0010] The bottom portion of the inner container may be formed in a raised bottom state in which a portion excluding an outer edge portion is depressed upward (the invention of claim 5). In addition, it is possible to form a convex portion that fits into the depression at the bottom of the inner container (the invention of claim 6). Further, it is desirable that the height of the projection be smaller than the depth of the depression (the invention of claim 7).

The top plate of the induction heating section may be provided with a temperature detecting section for elastically contacting the bottom surface of the inner container and detecting the temperature of the inner container. .

[0012]

According to the electric pot of the first aspect of the present invention, when the induction heating section is driven in a state where the pot section is placed on the top plate of the induction heating section, the electric flux is generated by the magnetic flux from the induction coil. The inner container made of a conductive material in the pot generates heat, and the water contained therein is heated. At this time, in a state where hot water is stored, only the pot portion can be separated from the induction heating portion and carried. When the pot is removed, the induction heating unit alone can be used as an induction heating cooker for cooking cooked foods and fried foods by placing a pot or the like on a top plate.

[0013] Since the heat insulating wall is provided in the pot portion so as to surround the peripheral wall of the inner container, the boiling water can be kept warm even after the heating is stopped. Also,
When the user wants to use the hot water, the hot water can be easily poured out by the hot water supply mechanism provided at the upper part of the inner container. Furthermore, since the lower end of the outer wall constituting the heat insulating wall is located above the bottom of the inner container, even when a conductive material is used for the outer wall, it is suitable for induction heating the bottom of the inner container. The outer wall is less susceptible to the influence of the magnetic field from the heating coil, and it is possible to prevent the outer wall from becoming hot.

In this case, if the inside of the closed space of the heat insulating wall is decompressed (the second aspect of the present invention), a heat insulating wall having high strength and excellent heat insulating properties can be formed. At this time, the best heat insulation properties can be obtained by evacuating the closed space of the heat insulating wall, but on the other hand, the outer shell of the heat insulating wall must have high strength, and the plate thickness becomes large. The situation arises. On the other hand, according to the study of the present inventor, by setting the pressure in the sealed space to about 0.1 Torr (the invention of claim 4), the heat insulation is achieved while obtaining sufficient heat insulation similar to the case of vacuum. It has been found that the outer wall constituting the wall can be made of a relatively thin material.

Alternatively, a heat insulating material such as glass wool may be provided in the closed space of the heat insulating wall (the invention of claim 3). In this case also, strength is obtained and heat insulation is excellent. Insulated walls can be configured. According to the study of the present inventor, the pressure in the enclosed space is set to about 0.1 Torr after the heat insulating material is provided.
Invention), it has been found that heat insulation almost equivalent to that of a vacuum can be obtained.

Further, if the bottom of the inner container is formed in a raised bottom state in which the portion excluding the outer edge is depressed upward (the invention of claim 5), the pot portion is removed and placed on, for example, a flat table. At times, an air layer is formed between the bottom of the inner container and the table, and only a part of the bottom of the inner container contacts the table, so it is difficult for heat to escape along the table, Heat retention can be further enhanced.

At this time, if a convex portion is formed on the top plate of the induction heating section so as to fit into the depression at the bottom of the inner container (invention of claim 6), when the pot portion is set on the top plate, The pot portion can be placed without displacement by the fitting. Further, at this time, if the height of the projection is configured to be smaller than the depth of the depression (the invention of claim 7), when the pot is left standing on the top plate, the An air layer is formed between the bottom surface of the vessel and the top plate, and the heat retention can be improved.

Then, on the top plate of the induction heating section,
By providing a temperature detecting portion for elastically contacting the bottom surface of the inner container and detecting the temperature of the inner container (the invention of claim 8), the temperature of the inner container is reliably detected by the temperature detecting portion. By using the temperature detected by the temperature detector for control or the like, highly reliable temperature control or the like can be performed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows an entire configuration of an electric pot 1 according to the present embodiment. Here, the electric pot 1 includes an induction heating unit 2 which can be used alone as an induction heating cooking device as shown in FIG. As shown in FIG. 2, a pot portion 3 which is detachable from the induction heating portion 2 is provided.

As shown in FIGS. 1 and 3, the induction heating unit 2 includes a heating coil 5 for generating a magnetic field in a thin box-shaped main body case 4 and a high-frequency current applied to the heating coil 5. The apparatus is provided with a high-frequency power supply unit 6 for flowing, a cooling fan device 7 for cooling the heating coil 5, heat-generating components, and the like.

On the upper surface of the main body case 4 is provided a heat-resistant top plate 8 on which a heating vessel (pot portion 3 or another pot, etc.) is placed. In the circular area, a convex portion 8a that fits into the pot portion 3 and performs a function of preventing displacement is formed so as to protrude at a slight height as described later. In addition, as shown in FIG. 4, a hole 8b in which the temperature detector 9 is disposed is provided in the center of the top plate 8.

The heating coil 5 is attached to a heating coil base 10 and is disposed below the top plate 8.
The heating coil base 10 is mounted so as to be able to move up and down slightly with respect to the bottom of the main body case 4 and urged upward by a spring 11. The temperature detector 9
As shown in FIG. 4, a thermistor 13 is attached to the back side of the upper wall of the heat-sensitive plate 12 whose lower end is fixed to the heating coil base 10, and the upper end of the heat-sensitive plate 12 is The top plate 8 (the projection 8) penetrates the hole 8b.
It protrudes from the upper surface of a) by a slight height.
At this time, a rubber packing 14 is provided between the inner edge of the hole 8 b and the heat-sensitive plate 12.
We try to prevent invasion of water etc. into the inside.

When the heating vessel (pot portion 3 or pot) is placed on the top plate 8, the heat sensitive plate 12
The upper surface of the heating container elastically contacts the bottom of the heating container, and the thermistor 13 can reliably detect the temperature of the bottom surface of the heating container. In addition, the heating container allows the temperature detecting section 9 (the heat-sensitive plate 12) to be pushed down slightly by a small amount. With this, the heating coil base 10 and thus the heating coil 5 are also pushed down integrally. become,
Thus, the distance A (see FIGS. 3 and 4) between the upper surface of the heat sensitive plate 12, that is, the bottom surface of the heating vessel and the heating coil 5 is always constant. This distance A is set so that the magnetic field of the heating coil 5 acts on the heating vessel most efficiently,
In this case, for example, it is 6 mm.

An operation panel 15 as shown in FIG. 5 is provided on the front surface (the left side in FIGS. 1 and 3) of the main body case 4. The operation panel 15 includes a power on,
On / off key 16 for turning off, stew using a pot, etc.,
General cooking selection key 1 for selecting cooking of fried food etc.
7, a pot selection key 18 for selecting water heating (heating) by the pot unit 3 described later and its heat retention, an output adjustment key 19 for adjusting a heating output, a general cooking, a pot, and which is selected; Display unit 2 that displays how much the heating output is adjusted with a lamp
0 is provided.

FIG. 6 shows an electrical configuration of the induction heating unit 2 including the heating coil 5 and the high-frequency power supply unit 6. Here, the DC power supply circuit 21 includes a rectifier circuit 22, a reactor 23, a smoothing capacitor 24, and the like, and rectifies a commercial power supplied through a power plug 25. The high-frequency power supply unit 6 includes a resonance capacitor 26, a switching element 27, a flywheel diode 28, and the like. The switching element 27 is turned on and off by a signal supplied from a base drive circuit 30 of an inverter control circuit 29. Based on this, a high-frequency current flows through the heating coil 5.

The inverter control circuit 29 includes a main control circuit 31 including a microcomputer, a timing circuit 32, an oscillation circuit 33, a PWM circuit 34, the base drive circuit 30, and a regenerative current detection circuit 35. I have.
The timing circuit 32 outputs a timing pulse at such a timing that the switching element 27 is turned on when no voltage is applied to the collector of the switching element 27. The oscillation circuit 33 generates a sawtooth wave based on the timing pulse, and the PWM circuit 34 generates a square wave pulse based on the sawtooth wave and the output reference level signal output from the output terminal O1 of the main control circuit 31. It has become. The base drive circuit 30 shapes the square wave pulse to a level suitable for switching, applies the switching pulse to the base of the switching element 27, and turns on and off.

When the heating vessel is made of stainless steel, the regenerative current detection circuit 35
7, the current flowing through the switching element 27 is detected via the current transformer 36, and if the detected current value is larger than a predetermined value, the output is appropriately reduced to protect the switching element 27. It has become.
The DC power supply circuit 21 is also provided with a current transformer 37 for current detection so that the detected current is supplied to an input terminal I2 of an A / D converter (not shown) of the main control circuit 31. Has become.

Further, the main control circuit 31 is provided with a detection signal of the thermistor 13 to an input terminal I1 and each key 1 of the operation panel 15
Signals from 6 to 19 are input. The main control circuit 31 outputs an output terminal O based on the detected current of the current transformer 37 and the detected temperature of the thermistor 13 in response to the operation of each of the keys 16 to 19 of the operation panel 15.
1 outputs an output reference level signal, whereby the heating coil 5 is controlled. It should be noted that when water heating and heat retention by the pot section 3 are selected, the thermistor 13
Based on the detected temperature, the control described later is performed.

Now, the pot portion 3 will be described.
As shown in FIGS. 1 and 2, the pot portion 3 is roughly composed of a main body portion 38 having a substantially cylindrical container shape, and a lid portion 39 provided on an upper portion of the main body portion 38.
The main body 38 is, for example, a stainless steel plate (SU
From S304), a heat insulating wall portion 41 is provided on the outer peripheral portion of the inner container 40 which is formed in a bottomed cylindrical container shape and stores water (hot water).

The heat insulating wall portion 41 is formed by forming an enclosed space S by providing an outer wall body 42 with a gap around the inner container 40, and filling the enclosed space S with a heat insulating material 43 made of, for example, glass wool. Have been. The outer wall body 42
Is a stainless steel plate (SUS30
4), the inner container 40 at both upper and lower ends.
Is welded to the inner container 40, for example. Further, in the closed space S formed between the inner container 40 and the outer wall body 42, the heat insulating material 43 is accommodated, and in this case, the pressure is set to 0.1 Torr.

At this time, the heat insulating wall 41 (the outer wall 4
The lower end of (2) is located slightly higher than the bottom of the inner container 40. Thus, when the pot portion 3 (the main body portion 30) is placed on a flat surface, the lower end portion of the heat insulating wall portion 41 (the outer wall body 42) is slightly raised from the flat surface. Further, a decorative member 44 is provided so as to cover a gap between the flat surface formed at this time and the lower end of the heat insulating wall portion 41.

The bottom portion of the inner container 40 is not entirely flat, and is formed with a concave portion 40a whose inner portion is depressed upward except for an outer peripheral ring-shaped portion. Thus, the bottom of the inner container 40 is in a raised bottom state, so to speak, like a thread bottom of pottery. At this time, the projection 8a formed on the top plate 8 described above.
Is formed so as to fit into the concave portion 40a.
As shown in FIG. 1, the height of the projection 8 a is smaller than the depth of the recess 40 a, so that in the fitted state, the raised bottom is formed by the recess 40 a in the bottom of the inner container 40. Part and convex part 8a of top plate 8
A slight gap (air layer) is formed between the upper surface and the upper surface. The portion of the bottom of the inner container 40 which is raised by the recess 40a is located, for example, about 4 mm below the lower end of the heat insulating wall 41 (outer wall 42).

A tap hole 45 is provided at the upper part of the main body 38 at a position slightly protruding downward, and a hinge receiving part 46 is provided at the rear of the upper end of the main body 38. . Although not shown in detail, the main body 38
Is provided with a tapping pipe for guiding hot water from a tapping outlet (not shown) provided at the bottom of the inner container 40 to the tapping port 45, and furthermore, a handle for suspending the entire pot section 3 so as to be portable. A handle is also provided.

On the other hand, the lid 39 is provided with a well-known so-called pneumatic tapping mechanism in, for example, a plastic outer shell having a shape following the upper surface of the main body 28. . Further, a hinge portion 47 rotatably attached to the hinge receiving portion 46 and a steam vent hole (not shown) are provided. With this, this lid 3
Numeral 9 is attached to the main body 38 so as to be openable and closable and detachable, and closes the upper surface of the main body 38 (inner container 40) almost in a closed state as shown.

Although not shown, the tapping mechanism presses a push button provided on the upper portion of the lid 39 to raise the internal pressure to push out the hot water in the inner container 40 from the hot water outlet. Hot water is supplied from the hot water outlet 45 through a hot water pipe. Further, a lock button 48 for permitting and prohibiting the pressing operation of the push button is provided on the upper portion of the lid portion 39.

Next, the operation of the above configuration will be described with reference to FIGS. When the user wants to boil hot water using the pot section 3, water is stored in the inner container 40 of the pot section 3, and then the pot section 3 is placed on the top of the induction heating section 2 as shown in FIG. Place on plate 8. At this time, the protrusion 8a formed on the top plate 8 is
By fitting into the concave portion 40a of the “0”, the pot portion 3
It is set on the top plate 8 without shifting.
In addition, the heat sensitive plate 12 of the temperature detecting section 9 is connected to the inner container 40 (the concave portion 4).
0a) comes into elastic contact with the bottom surface.

The user turns on the pot selection key 18 of the operation panel 15 and operates the output adjustment key 19 to set the temperature to a desired temperature (for example, 90 ° C.). Then, the main control circuit 31 controls the heating coil 5 based on the temperature detected by the thermistor 13 in the procedure shown in the flowchart of FIG. FIG.
5 shows the relationship between the operation of the heating coil 5 and the temperature of the hot water with the lapse of time at this time.

That is, FIG. 7 shows a control procedure when the temperature is set to 90 ° C. Here, when the pot is selected (Yes in step S1), the detected temperature is first set to 86 ° C. Is determined (step S2). If the temperature is below (Yes), the heating coil 5 is continuously energized until the temperature rises to 86 ° C. or more (step S3). As a result, an eddy current flows through the pot portion 3 (the inner container 40) by the magnetic field formed by the heating coil 5 so that the pot portion 3 (the inner container 40) is heated by induction and the water inside is heated. At this time, as described above, since the gap having the optimum dimension A is formed between the heating coil 5 and the bottom surface of the inner container 40, efficient heating is performed.

When the detected temperature becomes 86 ° C. or higher following this heating (No in step S2), it is determined in the next step S4 whether the detected temperature is higher than 94 ° C. When the detected temperature is lower than or equal to 94 ° C. (No in step S4), the energization of the heating coil 5 is still continued, and when the detected temperature finally exceeds 94 ° C. (Yes in step S4), the heating coil is turned off. 5 is cut off and the heating is stopped (step S5). Further, the detection temperature (temperature of hot water) gradually decreases due to the stop of the heating, but if the detection temperature falls below 86 ° C. (Ye in step S2).
s) Heating is performed again.

By such control, as shown in FIG. 8, the heating coil 5 is continuously energized until the water at normal temperature reaches 94 ° C., and thereafter the temperature of the hot water falls within the range of 86 to 94 ° C. The power cutoff control of the heating coil 5 is performed so as to be maintained. Thus, the water is heated to the set temperature and the hot water is kept at the set temperature ± 4 ° C.

At this time, the inner container 40 of the pot portion 3
Since the heat insulating wall portion 41 is provided on the outer periphery of the heating coil 5, the heat retaining property is improved, and the temperature drop when the heating coil 5 is cut off can be suppressed to a small value. Further, in this embodiment, the inner container 4
0 (concave portion 40a) and top plate 8 (convex portion 8a), a slight space is formed, so that an air layer is formed, and heat radiation from the bottom of inner container 40 is suppressed, It is possible to improve the heat retention when the heating coil 5 is cut off.

Since the outer wall 42 constituting the heat insulating wall 41 on the outer periphery of the inner container 40 of the pot portion 3 is made of stainless steel equivalent to the inner container 40, even the outer wall 42 includes the heating coil 5 as well. When induction heating is performed under the influence of the magnetic field, energy efficiency is reduced and the outer wall 42
May be heated to a high temperature. However, in the present embodiment, the lower end of the outer wall body 42 is
Since the outer wall 42 is located above the bottom of Oa), it is possible to make the outer wall 42 less susceptible to the influence of the magnetic field from the heating coil 5, and to prevent the outer wall 42 from becoming high in temperature.

FIG. 9 shows the relationship between the gap size between the heating coil 5 and the heating vessel and the reactive power. The strength of the electric field acting on the heating vessel is inversely proportional to the square of the gap size. It has been known. Here, since the gap dimension A between the heating coil 5 and the bottom of the inner container 40 (the concave portion 40a) is 6 mm as described above, the inner container 4
0 can be efficiently heated, while the heating coil 5
Since the gap dimension between the outer wall 42 and the lower end of the outer wall 42 is about 10 mm, the outer wall 42 is hardly heated.

When using boiling water, the user presses a push button on the lid 39 with a container (eg, a teapot) placed below the tap hole 45 to supply the hot water. Hot water is supplied from the hot water outlet 45 by the mechanism. At this time, the pot portion 3 can be used while being set in the induction heating portion 2. However, the pot portion 3 is removed from the induction heating portion 2, and only the pot portion 3 is carried to a place where hot water is used. be able to. In a state where the pot portion 3 is removed, the induction heating portion 2 alone can be used as an induction heating cooker for placing a pot or the like on the top plate 8 and cooking boiled foods and fried foods. It is.

FIG. 2 shows a state in which the pot section 3 has been removed from the induction heating section 2 and placed on a flat table T. Since the pot portion 3 has the heat insulating wall portion 41 on the outer periphery of the inner container 3, heat radiation from the peripheral surface portion is suppressed, and good heat retention can be secured. When the pot portion 3 is placed on the table T, only the peripheral portion of the bottom of the inner container 40 comes into contact with the table T, and the concave portion 40a of the inner container 40 makes contact with the table T. Since the air layer is formed, the heat of the pot portion 3 hardly escapes along the table T, and the heat retention can be further improved.

In the present embodiment, the heat insulating wall 41
The outer space 42 is provided on the outer periphery of the inner
Is formed in the closed space S, and a heat insulating material 43 made of, for example, glass wool is filled in the closed space S.
It is configured as a pressure of 1 Torr. According to the research of the present inventor, by using the heat insulating wall portion 41 having such a configuration, high heat insulating properties can be obtained and the outer wall member 4 can be obtained.
It turned out that strength was not so much needed for 2.

That is, FIG. 10 shows the result of examining how much the temperature of the hot water at 95 ° C. decreases over time by making the inside of the closed space S of the heat insulating wall portion 41 various configurations. In the drawing, a is a vacuum in the closed space S, b is a configuration of the present embodiment in which the heat insulating material 43 is accommodated in the closed space S and the pressure is reduced to 0.1 Torr, and c is a closed space S. In this case, only the heat insulating material 43 is accommodated therein, and d is the air layer as it is without the heat insulating material in the closed space S and without decompression.

As a result, the heat insulating material 43 containing the heat insulating material 43 and reduced in pressure to 0.1 Torr as shown in this embodiment (b) has a heat insulating property close to that of the vacuum (a) having the best heat insulating property. It was clarified that superior heat retention was obtained as compared with the case of only the heat insulating material 43 (c) and the case of only the air layer (d). Here, when the inside of the closed space S is evacuated, the outer shell (the inner container 40 and the outer wall 42) of the heat insulating wall portion 41 must have high strength, and the plate thickness of the outer wall 42 becomes large. The situation arises.

However, as in this embodiment, 0.1 Torr
When the degree of vacuum is as low as r, the outer wall 42 and the like do not need to have much strength, and can be made of a material having a relatively small thickness. Incidentally, FIG. 11 shows the relationship between the degree of vacuum and the durable plate thickness of the stainless steel plate (SUS304). As is clear from this figure, in the case of a low degree of vacuum of 0.1 Torr, 0.3 mm The plate thickness can be sufficiently used. Therefore, in the heat insulating wall portion 41 of the present embodiment, it is possible to obtain the same good heat insulating property as that obtained by evacuating the closed space S, and furthermore, the outer shell constituting the heat insulating wall portion 41 has a considerable strength. Can be eliminated.

As described above, according to the present embodiment, the pot portion 3 is detachably set in the induction heating portion 2 which can be used alone as the induction heating cooking device so as to boil water. Since the heat insulating wall portion 41 is provided in the pot portion 3, unlike the conventional hot water container that can only be used like a medicine can, the water that has been once boiled is kept well after the heating is stopped. can do. In particular, in the present embodiment, the heat insulating wall portion 41 is configured by filling the heat insulating material 43 in the closed space S and reducing the pressure to 0.1 Torr.
While obtaining the same good thermal insulation as when vacuumed,
It is easy to manufacture with a simple configuration and can be inexpensive.

Since the lower end of the heat insulating wall 41 (outer wall 42) is located above the bottom surface of the inner container 40, the outer wall 42 is prevented from generating heat due to the magnetic field from the heating coil 5. As a result, it is possible to prevent the energy efficiency from lowering and prevent the outer wall from becoming hot.

In the present embodiment, in particular, the concave portion 40a is formed in the bottom of the inner container 40 to raise the bottom, so that the heat retention when the pot portion 3 is removed and placed on the table T is further improved. In addition, since the projections 8a that fit into the recesses 40a are formed on the top plate 8 of the induction heating unit 2, the pots 3 can be placed without displacement by fitting them. At this time, since the height of the projection 8a is configured to be smaller than the depth of the recess 40a, the heat retaining property when the pot 3 is left standing on the top plate 8 is improved. Can be.

Further, in the present embodiment, the temperature detecting section 9 is provided on the top plate 8 of the induction heating section 2 so as to elastically contact the bottom surface of the inner container 40.
The advantages of being able to reliably detect the temperature of the inner container 40, performing highly reliable temperature control, and keeping the gap between the heating coil 5 and the heating vessel constant are also obtained. Is what you can do.

FIGS. 12 and 13 show other embodiments which are different from each other, and both have different structures of the heat insulating wall from the above-described embodiment. First, in FIG.
Is configured as follows.
That is, the heat-insulating wall portion 51 is also provided with the outer wall body 42 around the inner container 40 and forms a closed space S therebetween. Here, the inside of the closed space S is evacuated. ing. According to this, as described above (FIG. 1)
0) and the most favorable heat retention can be obtained.

On the other hand, the heat insulating wall portion 52 shown in FIG. 13 also has the outer wall body 42 provided around the inner container 40, and the outer surface of the inner container 40 and the outer wall The heat insulating material 53 is accommodated in a state where the air gaps S1 and S2 are secured between the inner surfaces of the heat insulating material 53 and the inner surface of the heat insulating material 53, respectively. In this case, as the heat insulating material 53, for example, a blanket-shaped vacuum heat insulating material “AURA” (made by Owens-Corning, USA) using glass fiber as a core material is used. At the same time, the inside of the closed space S is 0.1 Torr.
The pressure is reduced to about r. Further, in this embodiment, an outer case 54 made of, for example, plastic is provided further outside the outer wall body 42 with a gap.

According to this configuration, since the heat insulating material 53 is not in contact with the outer surface of the inner container 40 and the inner surface of the outer wall 42, the amount of heat transfer from the inner container 40 to the outer wall 42 is further reduced. Excellent heat retention can be obtained. In the figure, the relationship between the position in the circumferential direction in the heat insulating wall portion 52 and the temperature is indicated by a bold line, and as is clear from this, almost all the heat of the inner container 40 is transferred to the outer wall 42 and the outer case 54. It can be hidden.

[0057]

As apparent from the above description, the present invention has the following excellent effects. That is, according to the electric pot of the first aspect, the pot portion is detachably set to the induction heating portion so as to boil the hot water by the induction heating, so that the pot portion surrounds the peripheral wall of the inner container. Since the heat insulating wall is provided, it is possible to secure good heat retention after the heating is stopped, and further configure the heat insulating wall.
Since the lower end of the outer wall is located above the bottom of the inner container, the outer wall can be prevented from becoming hot.

In this case, if the inside of the closed space of the heat insulating wall is made to be in a reduced pressure state (the electric pot of the second aspect), a heat insulating wall having high strength and excellent heat insulating properties can be formed. Alternatively, a heat insulating material such as glass wool may be provided in the closed space of the heat insulating wall (the electric pot of claim 3). In this case, too, the heat insulating wall having high strength and excellent heat insulating properties. Can be configured. At this time, by setting the pressure in the closed space to about 0.1 Torr (the electric pot of claim 4), the outer wall constituting the heat insulating wall portion is compared while obtaining sufficient heat insulating properties close to the case of vacuum. It is possible to use a material having a very small thickness, and it is possible to use a simple structure and to reduce the cost.

Further, if the bottom of the inner container is formed in a raised bottom state in which the portion excluding the outer edge is depressed upward (the invention of claim 5), the pot portion is removed and placed on a flat table, for example. And the like can further enhance the heat retention. At this time, if a convex portion is formed on the top plate of the induction heating section to fit into the recess at the bottom of the inner container (the electric pot of claim 6), the pot portion is not displaced on the top plate by the fitting. Can be placed on Further, at this time, if the height of the projection is configured to be smaller than the depth of the depression (the electric pot of claim 7), when the pot is left standing on the top plate, An air layer is formed between the bottom surface of the inner container and the top plate, and the heat retention can be improved.

Then, on the top plate of the induction heating section,
By providing a temperature detector for detecting the temperature of the inner container by elastically contacting the bottom surface of the inner container (the electric pot of claim 8), the temperature of the inner container is reliably detected by the temperature detector. By using the temperature detected by the temperature detection unit for control or the like, highly reliable temperature control or the like can be performed.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, and is an overall vertical side view.

FIG. 2 is a longitudinal sectional side view of a pot portion.

FIG. 3 is a vertical sectional side view of an induction heating unit.

FIG. 4 is an enlarged vertical sectional side view of a temperature detecting portion.

FIG. 5 is a plan view of an operation panel.

FIG. 6 is a diagram showing an electrical configuration of an induction heating unit.

FIG. 7 is a flowchart showing a procedure of temperature control.

FIG. 8 is a diagram showing a state of a temperature change of an inner container over time.

FIG. 9 is a diagram showing the relationship between the gap size between the heating coil and the heating vessel and the reactive power.

FIG. 10 is a diagram showing a relationship between a configuration of a heat insulating wall portion and heat retention.

FIG. 11 is a diagram showing the relationship between the degree of vacuum in a closed space and the usable plate thickness.

FIG. 12 is a view corresponding to FIG. 1, showing another embodiment of the present invention.

FIG. 13 is a cutaway perspective view of a heat insulating wall showing another different embodiment.

[Description of References] In the drawings, 1 is an electric pot, 2 is an induction heating section, 3 is a pot section, 5 is a heating coil, 6 is a high frequency power supply section, 8 is a top plate, 8a is a convex section, and 9 is a temperature detecting section. , 38 are the main body,
39 is a lid, 40 is an inner container, 40a is a recess, 41,5
Reference numerals 1 and 52 denote heat insulating walls, 42 denotes an outer wall, and 43 and 53 denote heat insulating materials.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-56-121523 (JP, A) JP-A-6-314589 (JP, A) JP-A-7-73964 (JP, A) 67526 (JP, U) JP-A-2-134930 (JP, U) JP-A 1-108224 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) A47J 27/21 101 A47J 41/00 305

Claims (8)

(57) [Claims] 1. An induction heating section having a high-frequency power supply section and a heating coil in a main body, and a pot section detachably mounted on a top plate on an upper surface of a main body of the induction heating section, The pot portion is formed of a metal conductive material in a bottomed container shape and stores water, a heat insulating wall portion provided to surround a peripheral wall of the inner container, and a tap water provided at an upper portion of the inner container. And a heat insulating wall portion forms a closed space with the inner container.
An outer wall made of a metal plate is provided on the outer periphery of the
An electric pot, wherein the lower end of the outer wall is located above the bottom of the inner container. 2. The inside of the closed space of the heat insulating wall is depressurized.
Electric kettle according to claim 1, wherein the that. Wherein an electric kettle according to claim 1, wherein the heat insulating material such as glass wool in the sealed space of the heat insulating wall is arranged. 4. The closed space of the heat insulating wall has a pressure of 0.1 Torr.
The electric pot according to claim 2 or 3, wherein the pressure is set to about r. 5. The electric pot according to claim 1, wherein a bottom portion of the inner container is formed in a raised bottom state in which a portion excluding an outer edge portion is depressed upward. 6. The electric pot according to claim 5, wherein the top plate of the induction heating section is formed with a convex portion that fits into a recess at the bottom of the inner container. 7. The electric pot according to claim 6, wherein the height of the projection is smaller than the depth of the depression. 8. The top plate of the induction heating section is provided with a temperature detecting section for elastically contacting the bottom surface of the inner container and detecting the temperature of the inner container.
8. The electric pot according to any one of items 7 to 7.