JPH10165304A - Pressure cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase thermal efficiency and to retain heat insulating even after heating is stopped by induction-heating a heater made of a magnetic metal in a pressure container made of a non-magnetic material having thermal insulation. SOLUTION: For cooking stew, a pressure container 1 made of a non- magnetic material having a low level of thermal conduction, for instance a heat resisting resin, and composed of a heater 2 made of a magnetic metal attached inside is placed on a main body section 5, a switch is turned ON and then cooking is started. At this time, although an inverter 3 is actuated to supply a heating high-frequency magnetic field from a heating coil 4 to the heater 2, the quantify of this high-frequency magnetic field, that is, the heating amount of the heater 2 or the existence of the heater 2 is detected to control current carrying. The switch is turned OFF after the passage of specified time after steam is injected from a pressure regulating valve and then heat insulation cooking is started. Since the pressure container 1 is made of a material having a low level of thermal conduction, heat produced by the heater 2 is stored in the container 1 and thus cooking is carried out even without adding any new power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooker for performing pressure cooking by electromagnetic induction heating.

[0002]

2. Description of the Related Art Conventionally, pots used in cookers utilizing the principle of electromagnetic induction heating are generally made of iron, enamel or stainless steel, or multi-layer pans clad with stainless steel such as stainless steel and iron or stainless steel and aluminum. Used in However, these are pots with wide-mouthed openings called one-handed or two-handed pots. Pressure cookers that can cook cooked beans and small fish in a short time and efficiently can be heated by direct heat such as gas or electric heating. There was only a dedicated pot for the ceremony.

[0003]

The advantages of electromagnetic induction heating are that it has a very high thermal efficiency in that the object to be heated can be directly heated, as compared with the above-mentioned conventional heating source, and it has a very high thermal efficiency. It is well known that there is no flame and it is safe.

An object of the present invention is to provide a pressure cooker for performing electromagnetic induction heating which is safe and excellent in thermal efficiency. Still another object of the present invention is to provide a pressure cooker with a stirring function that does not cause the food to be scorched.

[0005]

The pressure cooker of the present invention has a very high thermal efficiency by performing induction heating of a magnetic metal heating element in a pressure vessel made of a non-magnetic and heat-insulating material. In addition, even after the heating is stopped, adiabatic heat retention or the like can be performed with residual heat.

By providing a stirring means provided in the pressure vessel, adiabatic heating and stirring can be performed alternately or simultaneously.

[0007]

A pressure cooker according to claim 1, wherein a first inverter for converting commercial power into high-frequency power, a heating coil to which the high-frequency power is supplied, and a magnetic induction heating by the heating coil. By providing a pressure vessel having a metal heating element, a material having non-magnetic and poor thermal conductivity (for example, heat-resistant resin, composite material of wood and non-magnetic metal, etc.)
A heating vessel made of magnetic metal is adhered to the inner bottom surface of the pressure vessel (or plasma spraying), and cooking is performed by receiving a high-frequency magnetic field generated by a heating coil to generate heat.

At this time, since the pressure vessel has a heat insulating property, the heat efficiency becomes extremely high, and the heat insulation and the like can be performed with the residual heat even after the heating is stopped.

The pressure vessel has a pressure regulating valve for maintaining the pressure in the vessel at a predetermined pressure (about 0.6 to 2 atm) during heating and cooking, and a pressure regulating valve in case of failure of the pressure regulating valve. It is well known that a safety valve is provided to prevent the pressure inside the pump from rising abnormally.

[0010] The invention according to claim 2 is, in particular, a rotating magnetic field generating means for generating a rotating magnetic field, a second inverter for supplying high frequency power to the rotating magnetic field generating means, and a rotating magnetic field of the rotating magnetic field generating means. By providing the rotating stirring means, the heating element is heated by electromagnetic induction heating, and at the same time, the stirring means provided in the pressure vessel acts to receive the low-frequency rotating magnetic field and rotate the stirring blade. is there. Therefore, the food is stirred slowly while being heated, so that the food does not burn.

According to a third aspect of the present invention, in particular, the stirring means is a pressure cooker which alternately or simultaneously performs adiabatic heating and stirring by comprising a heating element made of a magnetic metal. The stirring and heating means made of a magnetic metal to which is attached receives a high-frequency magnetic field and acts as a throw-in heater, and at the same time, the stirring blade acts to stir the food by a rotating torque generated in a permanent magnet provided in the heating and stirring means. It is.

According to a fourth aspect of the present invention, a high frequency magnetic field generated by the heating coil is provided by providing a magnetic shield ring between the heating coil and the rotating magnetic field generating means for reducing mutual magnetic interference. And the low-frequency rotating magnetic field generated by the rotating magnetic field generating means acts so as not to magnetically interfere with each other.

[0013] The invention according to claim 5 is particularly provided with a timer means for starting time measurement of a predetermined time when the temperature in the pressure vessel reaches a predetermined value, thereby enabling automatic pressure cooking. Is what you do.

[0014]

【Example】

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to FIG. Reference numeral 1 denotes a pressure vessel made of a non-magnetic material having poor heat conductivity, such as a heat-resistant resin or wood, and a heating plate 2 made of, for example, a magnetic metal is attached to an inner bottom surface of the pressure vessel. An inverter 3 produces an AC power supply voltage different from the commercial power supply from the commercial power supply. 4 is this invar
A heating coil 5 connected to the heater 3 for performing induction heating is a main body for accommodating the inverter 3 and the heating coil 4. The pressure vessel 1 is placed on the upper surface of the main body 5.
Reference numeral 6 denotes a weight mounted on a pressure regulating valve for adjusting pressure, and reference numeral 7 denotes a safety device which works to release steam and reduce the internal pressure when the pressure regulating valve is closed.

The operation of this embodiment will be described below.
It is assumed that the pressure vessel 1 of the present embodiment is placed on the main body 5 and a switch (not shown) is turned on to start the stew cooking. When the switch is turned on, the inverter 3 operates to generate a high-frequency magnetic field for heating from the heating coil 4 to the heating element 2.
And is heated by the principle of electromagnetic induction heating,
Stew cooking is performed. (At this time, in this embodiment, the pressure vessel 1 is made of a non-magnetic material such as wood and heat-resistant resin.
It is not affected by this high frequency magnetic field.
That is, it is not heated. Means for detecting and controlling the amount of the high-frequency magnetic field generated from the heating coil 4, that is, the amount of heating of the heating element 2 and the presence / absence of the heating element 2 are publicly known (the explanation is omitted in this embodiment). After a predetermined period of time has elapsed since the steam was blown out from the pressure regulating valve provided in the pressure vessel 1 (the pressure inside the vessel reached a predetermined pressure of about 1 atm), the switch was turned off to start adiabatic cooking.

Since the pressure vessel 1 is made of a material having poor heat conductivity, the heat generated by the heating element 2 is stored in the pressure vessel, so that the food can be cooked without applying new electric power. While being cooked sufficiently, it is possible to keep the temperature for a long time until the lid of the pressure vessel is removed. Depending on the capacity of the food, even if the heating is stopped before the steam is blown out from the pressure regulating valve, sufficient pressure cooking can be performed, and a highly efficient cooking appliance can be realized. The heating element 2 has the same effect as a configuration in which a magnetic metal material is directly formed on the inner bottom surface of the pressure vessel 1 by means such as plasma spraying in addition to the configuration in which a plate made separately is attached as in the present embodiment. is there.

As described above, in the present embodiment, the heating element 2 in the pressure vessel 1 made of a material having poor heat conductivity is heated by electromagnetic induction heating, so that high heat efficiency and improved heat retention cooking performance can be achieved. It acts as a pressure cooker.

(Embodiment 2) Next, a second embodiment of the present invention will be described with reference to FIG. Reference numeral 10 denotes a pressure vessel made of a non-magnetic material having poor heat conductivity such as a heat-resistant resin. A heating element 11 using a non-magnetic metal such as SUS304 is attached to an inner bottom surface of the pressure vessel. The heating element 11 using SUS304 has a characteristic of generating heat when receiving a high-frequency magnetic field despite being a non-magnetic metal. Reference numeral 12 denotes stirring means for stirring the food with the stirring blades 12a. In this embodiment, a permanent magnet 12b magnetized at N-poles and S-poles provided at equal angles as shown in FIG.

Further, a soft iron plate 12c serving as a back yoke is coated on a portion of the stirring means 12 to which the permanent magnet 12b is attached, and a Teflon resin having an extremely low friction coefficient is coated on a bottom surface of the stirring means 12, to receive a low-frequency rotating magnetic field. And the stirring blade 12
a is rotated smoothly and is detachable. A first inverter 14 receives a commercial power supply voltage via a power cord therein and converts the frequency and voltage of the commercial power supply into a high-frequency voltage suitable for heating.
A heating coil 15 for generating a high-frequency magnetic field in response to the voltage of the inverter 14, a rotating magnetic field generating means 16 for generating a rotating magnetic field, and a second inverter 17 for supplying a predetermined current to the rotating magnetic field generating means. And

In this embodiment, the inverter 17 includes a control means for controlling the rotation / stop of the stirring means 12 in an open loop without detecting the position of the permanent magnet 12a provided in the stirring means 12. It is something that is. Next, the rotating magnetic field generating means 16 will be described with reference to FIG. The rotating magnetic field generating means 16 includes a winding 21 and a magnetic core 22. The winding 21 is a normal general 3
Terminals 21a and 21 are wound to perform phase driving.
A rotating magnetic field is generated by supplying a three-phase current to b · 21c. The terminals 21a, 21b and 21c are connected to the second inverter 17, whereby the low frequency current having a stop period such as right rotation / stop / left rotation / stop / right rotation is supplied to the stirring means 12 for example. Is to be supplied. FIG. 4 is a partial sectional view of the pressure vessel 1 and the main body 13. A rotating magnetic field generating means 16, that is, a winding 21 and a magnetic core 22 are arranged on the outer periphery of the heating coil 15.

The operation of this embodiment will be described below.
It is assumed that the food is put in the pressure vessel 1, placed on the main body 10, and a switch (not shown) is turned on to start the stew cooking. When the switch is turned on, the first inverter
The heater 14 and the second inverter 17 operate alternately or simultaneously, so that a heating high-frequency magnetic field is supplied from the heating coil 15 and a low-frequency rotating magnetic field is supplied from the rotating magnetic field generating means 16.

At this time, in this embodiment, the pressure vessel 10 is made of a non-magnetic material, and is not affected by the high-frequency magnetic field and the low-frequency rotating magnetic field. That is,
It does not heat or rotate. Further, the stirring means 12
Because of the presence of the permanent magnet 12b, when the low-frequency rotating magnetic field is received, a rotating torque is generated to perform the stirring operation, but is not affected by the high-frequency magnetic field.

On the other hand, since the heating element 11 is made of a non-magnetic metal such as SUS304, it is not affected by the low-frequency rotating magnetic field.
In step S304, heat is generated by a high-frequency magnetic field despite the fact that it is a non-magnetic metal. More specifically, in this embodiment, the thickness of the heating element 11 is set to be as thin as about 0.6 mm or less. When a material having such a thickness is used, practically sufficient heating performance can be obtained by the skin effect. The frequency f of the rotating magnetic field generated from the rotating magnetic field generating means shown in FIG. 3B is as follows: f (Hz) = N / 60 × P / 2 N: Rotational Speed (r / m)
P is expressed by the number of poles, and the number of rotations required in a general stirring operation is at most about N <10000 (r / m). Here, even if the number of poles is P = 4, the frequency is f = 333 (Hz), which is a low frequency, so that this low-frequency rotating magnetic field is hardly absorbed by the nonmagnetic metal at the bottom inside the pressure vessel. is there.

As described above, the present embodiment functions as a pressure cooker having both heating and stirring functions. That is, it is possible to cook the food in a short time by the pressure, and to agitate the food so as to be immersed in the cooking juice evenly.

Depending on the contents of the cooking (mashed potatoes, etc.), it is also possible to change the shape and the stirring speed of the stirring means 12 to grind.

In this embodiment, since the stirring means 12 is detachable, the stirring means 12 can be freely removed when only heating or cleaning is desired.

In the present embodiment, the configuration is such that the permanent magnet 12b is embedded in the stirring means 12. However, a configuration in which a ring-shaped magnet material is magnetized may be used, and the core loss of the magnetic core 22 slightly increases. The same operation can be achieved by using low-cost soft iron or the like.

Embodiment 3 Next, a third embodiment of the present invention will be described with reference to FIG. 30 is a pressure vessel made of a non-magnetic material such as a heat-resistant resin or ceramics,
Numeral 31 is a magnetic metal heating and stirring means to which a plurality of permanent magnets 31a and stirring blades 31b are attached. A main body 32 includes a heating coil 33, a rotating magnetic field generating means 34, a first inverter 35, and a second inverter 36 in the main body 32.

Hereinafter, the operation of this embodiment will be described.
As in the previous embodiment, when a high-frequency magnetic field and a low-frequency rotating magnetic field are applied to the pan, the heating and stirring means 31 made of magnetic metal receives the high-frequency magnetic field and generates heat. That is, the heating and stirring means 3
1 acts as a throw-in type heater to heat the food. At the same time, the permanent magnet 31a attached to the heating and stirring means 31 receives the low-frequency rotating magnetic field and generates a rotation torque, so that rotation is started, and the stirring blade 31b stirs the food. Thus, in the present embodiment, both functions of heating and stirring are realized at the same time. The pressure container 30 is made of a non-magnetic material, and only functions as a container for cooking products to withstand a predetermined pressure as in the above-described embodiment.

At this time, in this embodiment, the heating and stirring means 31
Is detachable, so that the pressure vessel 30 can be freely removed when it is desired to wash it.

(Embodiment 4) Next, a fourth embodiment of the present invention will be described with reference to FIG. In FIG. 6, 40
Is a pressure vessel made of a non-magnetic material having poor heat conductivity, such as a heat-resistant resin.
The heating element 41 using a nonmagnetic metal as in S304 is attached. 42 is a stirring blade 42a for stirring the food.
And a permanent magnet 42b for generating a rotational torque and a back yaw.
This is a stirring means constituted by the nozzle 42c. Further, similarly to the above-described embodiment, the bottom surface of the stirring means 42 is coated with a Teflon resin having an extremely low friction coefficient. Things. Reference numeral 43 denotes a main body, which internally receives a commercial power supply voltage via a power cord, converts a frequency and a voltage of the commercial power supply into a high-frequency voltage suitable for heating, and a voltage of the first inverter 44. A heating coil 45 for generating a high-frequency magnetic field in response to this, a rotating magnetic field generating means 46 for generating a rotating magnetic field, a second inverter 47 for supplying a predetermined current to the rotating magnetic field generating means,
A magnetic shield ring 48 is provided between the heating coil 45 and the rotating magnetic field generating means 46 for reducing mutual magnetic interference.

Hereinafter, the operation of this embodiment will be described.
It is assumed that the food is put in the pressure vessel 40, placed on the main body 41, and a switch (not shown) is turned on to start the stew cooking. When the switch is turned on, the first inverter
The heater 44 and the second inverter 47 operate alternately or simultaneously, so that a heating high-frequency magnetic field is supplied from the heating coil 45 and a low-frequency rotating magnetic field is supplied from the rotating magnetic field generating means 46.

At this time, in this embodiment, the pressure vessel 40 is made of a non-magnetic material, and is not affected by the high-frequency magnetic field and the low-frequency rotating magnetic field. That is,
It does not heat or rotate. The stirring means 42 is
Because of the presence of the permanent magnet 42a, when the low-frequency rotating magnetic field is received, a rotating torque is generated to perform the stirring operation, but is not affected by the high-frequency magnetic field.

On the other hand, since the heating element 41 is made of a nonmagnetic metal such as SUS304 having a thickness as thin as about 0.6 mm or less, it is not affected by the low-frequency rotating magnetic field. Are generated by the high-frequency magnetic field.

As described above, the present embodiment functions as a pressure cooker having both heating and stirring functions at the same time. The magnetic shield ring 48 is made of a non-magnetic material such as aluminum in the present embodiment, and prevents the high frequency magnetic field generated from the heating coil 45 from crossing the rotating magnetic field generating means 46. As a result, the high-frequency voltage induced in the winding constituting the rotating magnetic field generating means by the high-frequency magnetic field is reduced, and the withstand voltage rank of the power element used for the second inverter 47 can be made lower. And can be realized at lower cost. In this embodiment,
Although the configuration is such that the magnetic shield ring 48 is made of aluminum, a similar effect can be obtained by using a configuration in which a magnetic body is placed below the heating coil 45.

In place of the heating element 41 and the stirring means 42,
The description of the embodiment in the case of using the heating and stirring means will be omitted because the operation and operation of the magnetic shield ring are the same as those described above.

(Embodiment 5) Next, a fifth embodiment of the present invention will be described with reference to FIG. Reference numeral 50 denotes a pressure vessel made of a non-magnetic material having poor thermal conductivity such as a heat-resistant resin.
1 is attached. Reference numeral 52 denotes a main body, in which an inverter 53 for generating an AC power supply voltage different from the commercial power supply from a commercial power supply, a heating coil 54 connected to the inverter 53 for performing induction heating, and a timer. Means 55 is included. Reference numeral 56 denotes temperature detecting means for detecting that the temperature in the pressure vessel 50 has reached a predetermined temperature (the pressure in the vessel has reached a desired pressure of about 1 atm). After this temperature detection, the timer means 55 Start operation. Although not shown, the connection between the temperature detecting means 56 and the main body 50 has a detachable connector type structure.

The operation of this embodiment will be described below.
The pressure vessel 50 of this embodiment is placed on the main body 52,
It is assumed that a desired time is set in the timer means 55, a switch (not shown) is turned on, and stew cooking is started. When the switch is turned on, the inverter 53 operates, and a high-frequency magnetic field for heating is started to be supplied from the heating coil 54 to the heating element 51. The heating element is heated by the principle of electromagnetic induction heating, and stew cooking is performed.

When the temperature detecting means provided in the pressure vessel 50 detects a predetermined temperature, the timer means 55 starts operating, and after a set time has elapsed, the timer means 55 turns off the switch. . As described above, in this embodiment, pressure cooking can be performed very easily.

(Embodiment 6) Next, a sixth embodiment of the present invention will be described with reference to FIG. Reference numeral 60 denotes a pressure vessel made of a non-magnetic material having poor thermal conductivity such as a heat-resistant resin. A heating element 61 using a non-magnetic metal such as SUS304 is attached to the inner bottom surface of the pressure vessel. .
As described above, the heating element 61 using SUS304 has a thickness as thin as about 0.6 mm or less, and generates heat when receiving a high-frequency magnetic field despite being a nonmagnetic metal. It has the characteristic of. Reference numeral 62 denotes a stirring means constituted by a stirring blade 62a for stirring the food, a permanent magnet 62b for applying a rotating torque, and a soft iron plate 62c serving as a back yoke. 63 is a main body part, which receives a commercial power supply voltage through a power cord inside,
A first inverter 64 for converting the frequency and voltage of the commercial power supply into a high-frequency voltage suitable for heating;
Coil 65 that generates a high-frequency magnetic field by receiving a voltage
A rotating magnetic field generating means 66 for generating a rotating magnetic field, a second inverter 67 for supplying a predetermined current to the rotating magnetic field generating means, and a timer means 68. 69
Is a temperature detecting means for detecting that the temperature in the pressure vessel 60 has reached a predetermined temperature. After this temperature detection, the timer means 68 starts operating.

Hereinafter, the operation of this embodiment will be described.
It is assumed that the food is put in the pressure vessel 60, placed on the main body 61, the desired time is set in the timer means 68, and a switch (not shown) is turned on to start the stew cooking.
When the switch is turned on, the first inverter 64 and the second inverter 67 operate alternately or simultaneously, so that a high-frequency magnetic field for heating from the heating coil 65 and a low frequency from the rotating magnetic field generating means 66 are low. A rotating magnetic field of a frequency starts to be supplied.

At this time, in this embodiment, the pressure vessel 60 is formed of a non-magnetic material, and is not affected by the high-frequency magnetic field and the low-frequency rotating magnetic field. That is, neither heating nor rotation is performed. Further, since the stirring means 62 includes the permanent magnet 62a, when the low frequency rotating magnetic field is received, a rotating torque is generated to perform the stirring operation, but is not affected by the high frequency magnetic field.

On the other hand, since the heating element 61 is made of a non-magnetic metal such as SUS304 having a thickness as thin as about 0.6 mm or less, it is not affected by the low-frequency rotating magnetic field. Are generated by the high-frequency magnetic field. After that, the temperature detecting means 6 was provided in the pressure vessel 60.
When 9 detects a predetermined temperature (the inside of the container has reached a predetermined pressure), the timer means 68 starts operating, and after a set time has elapsed, the timer means 68 turns off the switch. . As described above, in this embodiment, pressure cooking can be performed very easily.

(Embodiment 7) Next, a seventh embodiment of the present invention will be described with reference to FIG. 70 is a pressure vessel made of a non-magnetic material such as heat-resistant resin or ceramics, and 71 is a plurality of permanent magnets 71a and stirring blades 71b.
Is a heating and stirring means made of a magnetic metal to which is attached. Reference numeral 72 denotes a main body. The main body 72 includes a heating coil 73, a rotating magnetic field generating means 74, a first inverter 75, a second inverter 76, and a timer means 77. 78 is
Temperature detecting means for detecting that the temperature in the pressure vessel 70 has reached a predetermined temperature;
Means 77 starts operating.

The operation of this embodiment will be described below.
As in the previous embodiment, when a high-frequency magnetic field and a low-frequency rotating magnetic field are applied to the pan, the heating and stirring means 71 made of a magnetic metal receives the high-frequency magnetic field and generates heat to heat the food. at the same time,
Permanent magnet 71a attached to heating and stirring means 71
Receives the low-frequency rotating magnetic field and generates a rotating torque, so that rotation is started, and the stirring blade 71b stirs the food.
Thereafter, when the temperature detecting means 78 provided in the pressure vessel 70 detects that the temperature has reached a predetermined temperature, the timer means 77
Starts operation, and after a set time has elapsed, the timer means 77 turns off the switch. As described above, in this embodiment, pressure cooking can be performed very easily. Since the description of the sixth embodiment of the present invention using the magnetic shield ring in the second and third embodiments is the same as that of the above-described fourth embodiment, Omitted.

[0046]

As described above, the first aspect of the present invention provides
A first inverter that converts commercial power into high-frequency power,
By providing a heating coil to which the high-frequency power is supplied and a pressure vessel having a heating element made of a magnetic metal that is induction-heated by the heating coil, a pressure cooker that performs safe and highly efficient electromagnetic induction heating is realized. Is what you do.

The invention according to claim 2 is, in particular, a rotating magnetic field generating means for generating a rotating magnetic field, a second inverter for supplying high frequency power to the rotating magnetic field generating means, and a rotation of the rotating magnetic field generating means. The provision of the stirring means that rotates by the magnetic field enables the cooked food to be heated while stirring, thereby realizing a pressure cooker with a stirring function that is safe and has excellent heat efficiency and heat-retaining cooking performance.

According to the third aspect of the present invention, in particular, since the stirring means is constituted by a heating element made of a magnetic metal, the stirring means has a stirring function which is easy to handle, is safe, has excellent heat efficiency and is excellent in heat keeping cooking performance. A pressure cooker is realized.

Further, the invention according to claim 4 is particularly advantageous in that a structure provided with a magnetic shield ring for reducing mutual magnetic interference between the heating coil and the rotating magnetic field generating means has a lower cost. This realizes a pressure cooker with an agitation function that is safe and has excellent thermal efficiency and heat retention cooking performance.

Further, the invention according to claim 5 is, in particular, a detecting means provided in the pressure regulating valve of the pressure vessel for detecting that the valve is opened, and a predetermined time when the detecting means detects the opening of the valve. The present invention realizes a simple and safe pressure cooker as a configuration including an operating timer means.

Further, the invention according to claim 6 is a temperature detecting means for detecting that the inside of the pressure vessel has reached a predetermined temperature, and operates for a predetermined time after the detecting means detects the temperature. A simple and safe pressure cooker is realized as a configuration provided with a timer means.

[Brief description of the drawings]

FIG. 1 is a detailed view of a main part of a pressure cooker according to a first embodiment of the present invention.

FIG. 2 is a detailed view of a main part of a pressure cooker according to a second embodiment of the present invention.

FIG. 3 is a detailed view of a rotating magnetic field generating means of the pressure cooker.

FIG. 4 is a sectional view of a main part of the pressure cooker.

FIG. 5 is a detailed view of a main part of a pressure cooker according to a third embodiment of the present invention.

FIG. 6 is a sectional view of a main part of a pressure cooker according to a fourth embodiment of the present invention.

FIG. 7 is a detailed view of a main part of a pressure cooker according to a fifth embodiment of the present invention.

FIG. 8 is a sectional view of a main part of a pressure cooker according to a sixth embodiment of the present invention.

FIG. 9 is a sectional view of a main part of a pressure cooker according to a seventh embodiment of the present invention.

[Explanation of symbols]

 1, 10, 30, 40, 50, 60, 70 Pressure vessel 2, 11, 41, 51, 61 Heating element 3, 53 Inverter 4, 15, 45, 65 Heating coil 5, 32, 52, 63 Main body 6 Weight 7 Safety device 12, 42, 62 Stirrer 12a, 42a, 62a Stirrer blade 12b, 42b, 62b Permanent magnet 12c, 42c, 62c Back yoke 14, 35, 44, 64, 75 First inverter 15 , 36, 47, 67, 76 Second inverter 16, 34, 46 Rotating magnetic field generating means 21 Windings 21a, 21b, 21c Terminal 22 Magnetic core 31, 72 Heating and stirring means 31a, 72a Permanent magnets 31b, 72b Stirrer blade 48 Magnetic shield ring 55, 68, 77 Timer means 56, 69, 78 Temperature detecting means

Continuation of front page (72) Inventor Hideki Omori 1006 Ojidoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] A first inverter for converting a commercial power supply into high-frequency power; a heating coil to which the high-frequency power is supplied; and a pressure vessel having a magnetic metal heating element induction-heated by the heating coil. Pressure cooker. 2. A rotating magnetic field generating means for generating a rotating magnetic field, a second inverter for supplying high-frequency power to the rotating magnetic field generating means, and a stirring means rotating by the rotating magnetic field of the rotating magnetic field generating means. Item 4. A pressure cooker according to item 1. 3. The pressure cooker according to claim 2, wherein the stirring means is made of a magnetic metal heating element. 4. The pressure cooker according to claim 2, further comprising a magnetic shield ring between the heating coil and the rotating magnetic field generating means for reducing mutual magnetic interference. 5. The pressure cooker according to claim 1, further comprising timer means for starting a predetermined time when the temperature in the pressure vessel reaches a predetermined value.