JPS6219133A - Electric pot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electric water heater equipped with a metal vacuum container for heating beverages and the like.

(Prior art) Conventionally, this type of electric water heater
As proposed in Publication No. 32, a metal-controlled heater penetrating the vacuum layer of a vacuum container is provided to heat the beverage, and as proposed in Publication of Utility Model Application No. 59-101932 and Japanese Patent Application Publication No. 59-108518. As proposed, a heater is provided on the outer surface of the inner container within the vacuum layer, and heat from a heating element is conducted to the inner container via an electrical insulator to heat the beverage in the inner container.

(Problem to be solved by the invention) However, in the former case, since the heater is installed at a position away from the inner bottom of the inner container, when the amount of beverage becomes small, it may become dry-burned, and the heater may Because the surface power density is large, boiling noise and vibrations may occur when heating beverages.

In addition, in the latter case, due to the large thermal resistance in the transmission from the heating element to the beverage, the heating element becomes high temperature and outgas is generated, reducing the vacuum life and increasing radiant heat loss, making it difficult to keep the vacuum container warm. The effectiveness may be reduced, and heat loss may increase because the lead wires of the heater are led out of the vacuum sealing section. On the other hand, there is a heating method using an excitation coil, but it is possible that pressure is applied to both the inner and outer containers through a vacuum space, causing deformation.In order to maintain strength against pressure, the inner container must have a thickness of 3P. If it is made thicker, the heating efficiency of the excitation coil will decrease and it will become unusable. In addition, if the heating surface is flat and a temperature detection element is attached to the outer bottom, there is a drawback that dry firing cannot be detected until all the water in the inner container is completely exhausted.

(Means for solving the problems) The present invention has been made in order to eliminate the above-mentioned drawbacks,
To obtain an electric water heater which can heat even a small amount of beverage, prevents boiling noise and vibration, maintains the strength of the inner container and outer container, improves the detection sensitivity when completely burnt out, and has a long vacuum life. For this purpose, the bottom member of the outer container is formed to have an inwardly convex shape, and an excitation coil is provided on the outer surface of the bottom member of the outer container made of a non-magnetic material, and the bottom member is made of a magnetic material that is heated via the excitation coil. The bottom member of the inner container is formed in a convex shape along the bottom member of the outer container.

(Function) By doing this, the strength is maintained against the pressure applied to the inner and outer containers, and the inner container is efficiently heated by the excitation coil. Moreover, even a small amount of beverage can be heated efficiently, and This eliminates the generation of outgas such as the one described above, and allows the state of complete combustion to be detected before it reaches the side of the bottom member of the inner container.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

The structure of the embodiment is as shown in FIGS. 1, 2, 3, and 4. Reference numeral 1 denotes a vacuum container consisting of an inner container 101 having a spout 104 for water injection, and an outer container 102. Both containers 1
A sealed space 103 is formed between 01 and 102. The inner container 101 is made of a magnetic stainless steel plate,
The bottom member 105 is made of the same material as the bottom and is formed to have an inwardly convex shape, and is airtightly integrated at a joint 113 by welding the entire circumference or the like. The outer container 102 is made of a non-magnetic stainless steel plate, and is airtightly integrated with a bottom member 106 made of the same material that forms the bottom surface and formed into a convex shape along the bottom member 105 and a joint 112 by welding the entire circumference or the like. It's P. Reference numeral 107 denotes a recess, which is an elongated cylindrical recess provided in the center of the bottom member 106, and a bottomed cylindrical pipe 108 made of non-magnetic stainless steel connects the opening 106 with the joint 110 of the bottom member 106 by welding or the like. In addition, the bottom portion of the bottomed pipe 108 is joined to the bottom member 105 by welding or the like at a joint 109, so that they are integrated in terms of heat transfer. Therefore, the inner container 1o1 is airtightly fixed to the outer container 102 at the upper end of the mouth portion 104, and is also fixed at the center of the outer bottom of the bottom member 105 by the bottomed pipe 108.
A space 103 formed between both containers 101 and 102 is kept in a vacuum state.

Reference numeral 2 denotes a bottom body, which is a bottomed cylindrical body fixed to the lower part of the 1Ω vacuum container, and has legs 201 on its outer bottom surface for installation on a tabletop or the like. Reference numeral 6 denotes a handle, which is attached to the top and rear side of the vacuum container 1.

A button 302 is provided to rotate the stopper filter 01 that opens and closes the mouth portion 104 about a fulcrum 303, and a plug receiving portion 604 to which a power plug 305 is connected via a magnet is provided on the lower side surface. 7 is an electric circuit component and the bottom body 2
It is installed on the inner bottom. Reference numeral 5 denotes an excitation coil, which is attached to the bottom member 106 to generate a high-frequency magnetic field described later.
It is provided in a spiral shape on the outer bottom surface and heats the bottom member 105 by generating an eddy current in the bottom member 105. Reference numeral 701 is a rectifier circuit that converts the commercial power supply through the plug receiver 604 into DC, and the converted DC is converted into high-frequency current through the inverter circuit 702. A control circuit 703 inputs a control signal to the inverter circuit 702 via a driver circuit 704, converts the DC current from the inverter circuit 702 into a high-frequency current of a predetermined frequency, and energizes the excitation coil 5 to generate a high-frequency magnetic field. It is the basis. Reference numeral 6 denotes a temperature detection element, which is composed of a thermistor and is provided deep inside the bottomed pipe 108, detects the temperature of the water 4 in the inner container 101 via the bottom member 105, and outputs an electric signal according to this temperature. It is something to do. This electrical signal is applied to a control circuit 706 via a temperature detection circuit 705, and is used to change, for example, the output pulse width of the control circuit 703. Note that the rectifier circuit 70
1. Inverter circuit 702° control circuit 703. Driver circuit 704. The temperature detection circuit 7P path 705 is provided within the electrical circuit component Z.

710 and 711 are a comparator and a variable resistor for setting a reference voltage, respectively, and are housed in the control circuit 703.

As shown in FIG. 4, a variable resistor 711 and a temperature detection element 6 are connected to the input terminals of the comparator 710, respectively.

When the temperature of the water 4 rises and the output signal of the temperature detection element B exceeds the reference voltage set by the variable resistor 711, a signal corresponding to this deviation is output from the comparator 710 and sent to the control circuit 703. In addition to having the given configuration, it also has a similar circuit for preventing premature burning.

The operation of this embodiment based on the above configuration will be explained.

Fill the vacuum container 1 with water from the mouth 104, and plug the power plug 60.
5 is connected to the plug receiver section 604. Inverter circuit 7
A high frequency current flows from the excitation coil 5 to the excitation coil 5.
The bottom member 105 generates heat due to the high frequency magnetic field generated from the
Heat water 4 to raise its temperature.

At this time, the bottom member 105 generates heat because it is made of magnetic stainless steel material, and the bottom member 106 does not generate heat because it is made of non-magnetic stainless steel material. At this time, both containers 101 and 102 are preferably made thick in order to reduce heat loss.

The thicker the resistance, the greater the eddy current loss, so the thinner the bottom 105 is, the more heat can be obtained with the same magnetic field. In addition, the distance A between the nine bottom members 105 and 106 is made as small as possible,
The coupling coefficient between the primary inductance of the excitation coil 5 and the secondary inductance of the bottom member 105 is made close to 1 to efficiently heat the bottom member 105. In addition, the inner container 101 is supported at two locations above and below the joint 109 between the mouth portion 104 and the axis of the excitation coil 5 to provide mechanical strength and vibration resistance due to the electromagnetic force generated by the high frequency magnetic field of the excitation coil 5. To heat water 4 strongly and efficiently without changing over time.

That is, since the water 4 in the inner container 101 is heated by the entire surface of the bottom member 105, the surface area for heating the water 4 becomes large.
Even at high wattages, heat transfer occurs through nucleate boiling, and no noise or vibration occurs during boiling. When the temperature of the water 4 reaches, for example, a set value of 98°C, the temperature detection element 6 senses it and controls the current flowing to the excitation coil 5 to keep the rise in water temperature constant. In the same way, power supply is stopped. At this time, the temperature detection element 6 is installed in a bottomed pipe 108 that is thermally connected to the bottom member 105 to accurately detect the temperature of the water 4. The temperature at the center of the bottom member 105 is detected while the temperature is still present. In addition, since the bottomed pipe 108 has a small diameter and a thin wall, the heat conduction resistance from the bottom member 105 to the bottom member 106 is large, and heat loss due to heat release from water is small.

(Effects of the Invention) According to the present invention, the bottom member of the inner container made of a magnetic material and the bottom member of the outer container made of a non-magnetic material are each formed to have an inwardly convex shape, so that high pressure can be applied to both containers. It has a durable structure and an excitation coil is provided on the outer surface of the bottom member of the outer container, thereby eliminating the generation of outgas and extending the vacuum life. In addition, when heating the water in the inner container, it efficiently heats the bottom member of the inner container and quickly detects the uncooked state when the remaining amount of water is low, thereby maintaining the strength of both containers and boiling. It is possible to obtain an electric water heater that prevents noise and 0 P vibrations, prevents even a small amount of beverages from being fried, and has improved detection sensitivity when roasted.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of an electric water heater according to an embodiment of the present invention, Fig. 2 is a sectional view of the main parts, Fig. 6 is the electric circuit diagram, and Fig. 4 is an internal wiring diagram of the main parts. be. 101... Inner container, 102... Outer container. 105.106... Bottom member, 5... Excitation coil.

Claims (1)

[Claims] In an electric water heater that has a double structure of a metal inner container and an outer container, and the space formed between the inner and outer containers is a vacuum chamber, at least the bottom member (105) of the inner container (101)
) and at least the bottom member (106) of the outer container (102)
are made of magnetic material and non-magnetic material, respectively, and both bottom members (
105) and (106) are formed to have an inwardly convex shape, and an excitation coil (5) for heating the bottom member (105) is provided on the outer surface of the bottom member (106) of the outer container (102). An electric water heater featuring