JPS58143720A - Heater for pot and electric pot equipped therewith - 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 The present invention relates to a pot heater and an electric pot equipped with the heater.

Conventionally, electric pots have a structure in which a hole is made through the vacuum layer of a double vacuum container made of metal, and a heater is inserted into this part from the outside in a watertight manner, or a part of the bottom of the double vacuum container is made into a single layer. , a structure in which a heater is attached from the outside, or a heater is brazed directly to the bottom of the inner container of a vacuum double container, and an airtight terminal is provided on the outer container to draw out the lead wire.
Types with a similar structure are known, but the former two have poor insulation properties and consume a lot of power during heat retention, while the latter has good insulation properties but is inferior in productivity and is expensive. There were some drawbacks. Further, as heaters used in this type of electric kettle, there are mica heaters and sheathed heaters, but these require coating with a metal material due to their structure, and have a problem in corrosion resistance.

The present invention was made in view of these problems, and an object of the present invention is to provide a pot heater that can be attached to a container without drilling or other processing, and has excellent corrosion resistance and thermal efficiency. .

Another object of the present invention is to provide an electric kettle that can efficiently heat contents using the heater, has a simple structure, and is easy to manufacture.

The heater for a pot according to the present invention includes a ceramic base in the shape of a plate, a rod, or a tube, a resistor of a predetermined length buried in one end of the base, and a conductive element buried in the base along the longitudinal direction. It is characterized by comprising at least two external connection terminals connected to the resistor through the body and circumscribed on the other end side of the base body.

In one embodiment of the present invention, the resistor embedded in one end of the ceramic base is double-layered with a first resistor for low heat generation and a second resistor for high heat generation in order from the one end side. It is formed by In this embodiment ζ, the ends of the first and second resistors are connected to external connection terminals through independent conductors, or one end of the first resistor and one end of the second resistor are connected to an external connection terminal through independent conductors. are internally connected, and the connection portion thereof is connected to an external connection terminal via an independent conductor along with each other end of both paper antibodies.

In another embodiment, in order to detect the amount of contents in the pot, a plurality of water level detection electrodes are provided externally on the ceramic base at a predetermined interval from one end of the base, and each electrode is An external connection terminal provided externally on the other end of the base is connected via a conductor buried in the base. These water level detection electrodes are used as electrodes to detect the liquid level in the pot and operate the liquid level display device, and at the same time to drive the dry-cooking prevention device to prevent the pot from running dry. It can also be used as an electrode. Further, as electrodes for preventing dry cooking, a pair of water level detection electrodes may be formed at a predetermined distance from one end of the ceramic base.

The electric pot according to the present invention using the heater for a pot having the above-mentioned structure is other than a heater in which the heater is suspended from the upper opening of a container containing liquid and an external connection terminal is provided externally. It is constructed by installing with the end side up. Therefore, in the electric kettle of the present invention, since the heater is in direct contact with the contents, for example, water, heat loss is small and thermal efficiency can be significantly increased. Furthermore, since there is no need to perform any other processing on the container to attach the heater, the number of manufacturing steps for the container can be reduced, the pot can be easily assembled, and the container can be manufactured at low cost. Moreover, when a glass vacuum double bottle is used as the container, instead of only a metal vacuum double container, heat retention properties are significantly improved, and the power consumption required for heat retention can be extremely reduced.

Other objects, configurations, and effects of the present invention will become apparent from the following description with reference to the accompanying drawings that illustrate embodiments of the present invention.

In FIG. 1 showing a pot heater according to the present invention, 1
2 is a ceramic base, 2 is a resistor for low heat generation, 3 is a resistor for high heat generation, 4 is an external connection terminal, 5 is a conductor connecting both ends of each resistor and each external connection terminal 4, and resistor 2, 3 and the conductor 5 are buried in the surface layer of the ceramic base 1 so as not to come into contact with water during use. Further, even when the amount of water in the container decreases, the resistors 2 and 3 are buried in one end that will be on the lower side when attached to the pot, in order to generate convection in the water and heat it evenly above and below. The external connection terminal 4 is provided externally on the other end side of the base 1.

The pot heater having the above structure can be manufactured, for example, as follows. That is, first, a main body part 1a is prepared by forming powder of a ceramic material into a plate, cylinder, or rod shape (see Fig. 2a). Ink is printed on the resistive films 2 and 3 that form the resistor 2 and 3, and the lead wires are used as the resistive films 2 and 3. Note that as a material for forming the -I film 5, a known conductive paste containing silver, nickel, or tungsten may be used. Next, the ceramic sheet 1b is wound around the main body part 1a with the surface on which the resistive film is formed facing inside, and the ceramic sheet 1b is baked to integrate the ceramic sheet 1a, thereby easily manufacturing the ceramic sheet 1b. Note that the external connection terminals are formed using a conductive film formed on the back surface by drilling through holes 7 in advance in the positions where the external connection terminals are to be formed in the ceramic sheet, and applying conductive paste onto the through holes 7 from the front surface. 5 are electrically connected to each other, and can be formed by firing and baking this. Further, the width of the resistive film 2 is made narrow so that it has a high resistance, and the width of the conductive film 5 is made wide so that it has a low resistance.

Instead of forming the resistive film independently as shown in FIG. 2(b), a pattern as shown in FIG. 2(fc) may be adopted. In addition, the water level detection electrode is shown in Figure 2 (C
), a through hole 8 is made in the position where an electrode is to be formed in the ceramic sheet, and a conductive paste is applied from the front surface onto the through hole 8 to establish electrical continuity with the conductive film formed on the back surface. After that, this is fired, and nickel, silver,
It can be easily formed by applying other plating. When using a heater with a water level detection electrode formed in this way, there is no need to form a hole in the bottom of the container to communicate with the liquid level display tube as in the past, and the water level detection electrode can be installed independently on the container wall. There is no need to hang it from the opening of the container, making it easier to manufacture and assemble the pot.

Fig. 3 shows an electric pot of the present invention using a heater having a water level detection electrode, 10 is a heater, 11a to 11ie are water level detection electrodes, 12 is a metal vacuum double container, and an inner container 12a, an outer container It consists of a container 12b and an exhaust tip pipe 12C, and a vacuum is created between the inner container 12a and the outer container 12b. A metal inner lid 13 is brazed or welded to the upper open end of the vacuum double container 12 and has an opening 14 .

The heater 10 has a metal fitting 15 attached to its upper end, and a bottom 18 that closes the hollow portion of the heater 10 to its lower end. Further, a temperature sensor 16 (see FIG. 4) is inserted into the hollow portion of the heater 10, and this sensor is inserted into the bottom 18.
Fixed.

17 is a micro switch, 19 is a support metal fitting, 20 is an exterior body, 21 is an exterior bottom, 22 is an exterior shoulder body, 23 is an outer cover, and a level meter 50 (described later) is attached to the pouring port side of the body 21. There is. An inner plug 25 is removably inserted into the opening 14 of the inner lid 13 in the shoulder body 22.

The inner stopper 25 has a water lift pipe 26 and a water injection pipe 27, and a safety valve 28 is disposed in a flow path that communicates them.

A bellows pump consisting of a bellows 30, a spring 31, a steam cylinder 32, and a bellows upper plate 33 is installed inside the outer lid 23, and a bellows pump is provided at the lower end of the steam cylinder 32 for opening and closing the exhaust port 34 of the bellows pump. A valve body 35 is provided externally. In the illustrated example, the seal packing 36 attached to the bottom plate 37 of the outer lid 23 is used as the valve seat 38, but the lower end of the bellows exhaust pipe 39 may also be used as the valve seat. Since the upper end of the steam cylinder 32 is fixed to an intake cylinder 40 formed on the bellows upper plate 33, the valve body 35 is brought into close contact with the valve seat 38 by the action of the spring 31. In addition, the bellows upper plate 33
A gasket 41 is fitted into the intake cylinder 40 of the engine, and the gasket 41 and a cap 42 open and close the intake hole 43. The cap is biased upward by a spring 44 mounted on the exterior of the suction cylinder 40. ing.

45 is a steam hole, and 46 is a pusher body.

The electric kettle according to the present invention includes a control device 51 consisting of a heater control circuit, a liquid level display device, and an empty cooking prevention device. As shown in FIG. 4, this control device applies a pulse voltage, for example, a pulse with a pulse output period of 1 ms and a rest period of 4 seconds, between the reference electrode 11a and the other water level detection electrodes 11b to 11e. A pulse generating section 53 that performs
A water level detection section 54 detects conduction or non-conduction between the reference electrode 11a and other electrodes, and a low heat generation resistor 2 and a high heat generation resistor 3 of the heater 10 according to the output signal from the water level detection section. A control unit that controls energization to, for example, resistors 2 and 3
The triac trigger sections 57 and 58 control the triacs 55 and 56 connected in series to the heater 10, and the temperature is detected by the signal from the temperature sensor 16 attached to the bottom of the heater 10, and the signal is output to the triac trigger section 57 and 58. In response to the output signal from the temperature detecting section 59 and the water level detecting section 54, a display element, for example, the level meter 50
It is mainly composed of a driving section 60 that drives each element 61 of. Additionally, in order to prevent electric shock in the event that the heater is damaged, a voltage detection section 62 that detects the voltage of the container 12 and a power supply intermittent section 63 that turns off all circuits based on an output signal from the voltage detection section 62 are incorporated. A microswitch 17 is provided at the bottom of the pot to turn off the power if the pot is lifted or tipped over.

When using the electric kettle configured as described above, after filling the container 12 with water, inserting the plug 70 and turning on the electricity, the high heat generating resistor 3 or together with the low heat generating resistor 2 will boil water. , and then boiled for a predetermined time, and the high heat generation resistor 3 is stopped energized by a signal from the temperature sensor 16. From then on, only the low heat generation resistor 2 is connected to the temperature sensor 1.
It is activated by the output signal from 6 to keep warm. In addition, in conventional electric kettles, when boiling, steam enters the bellows and deforms the bellows, making it unusable. A penetrating steam cylinder 32 is provided,
This problem is solved by preventing steam from entering the bellows 30 by the valve body 35 and at the same time discharging it from the steam cylinder 32 to the outside through the intake hole 43 and the steam hole 45.

The water level detection electrodes 11b to 11ie are used to detect water conduction with the reference electrode and to display the amount of water using the water level display level meter 50, as well as to determine the boiling time depending on the wax type. Also, the space between the electrodes 11a and 11C is used to prevent the high heat generating resistor 3 from running dry, and the space between the electrodes 11a and llb is used to prevent the low heat generating resistor 2 from running dry.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway diagram of a pot heater according to the present invention;
21.+(a) is a perspective view showing the main part of the base in the manufacturing process, FIG. 2(b) is a developed view of the resistor forming part, and FIG. 2(C) is a developed view showing a modification thereof. , FIG. 3 is a sectional view showing an example of the electric kettle according to the present invention, and FIG. 4 is a block diagram of its electric circuit. 1... Ceramic base, 2. Discharge...resistance element, 4...
External connection terminal, 5... conductor, 7, 8... through hole,
DESCRIPTION OF SYMBOLS 10... Ceramic heater, 11a-lie... Water level detection electrode, 12... Container, 13... Inner lid.

Claims (7)

[Claims] (1) A plate-shaped, rod-shaped, or tubular ceramic base; a resistor of a predetermined length buried in one end of the base; and a conductor buried in the base along the longitudinal direction of the resistor. 1. A heater for a pot, comprising at least two external connection terminals connected to the body and provided externally at the other end of the base. (2) Claim 1, wherein the resistor is formed by dividing the ceramic base into two parts sequentially from one end side: a first resistor for low heat generation and a second resistor for high heat generation. Heater for the pot described. (3) One end of the first resistor and one end of the second resistor are connected inside the base, and the connection part is connected to an external connection terminal via a conductor, like the other ends of both resistors. A pot heater according to claim 2. (4) A plurality of water level detection electrodes are installed externally on the ceramic base at predetermined intervals from one end to the other, and each electrode is connected to the base through a conductor buried in the base. The pot heater according to any one of claims 1 to 3, which is connected to an external connection terminal provided externally on the other end side of the base. (5) A plate-shaped, rod-shaped, or tubular ceramic base, a resistor of a predetermined length buried in one end of the base, and a conductor buried in the base along the longitudinal direction of the resistor. A heater consisting of at least two external connection terminals that are connected to the body and provided externally on the other end of the base is mounted with the other end facing upward, where the upper part of the container containing the liquid is provided externally. An electric kettle featuring (6) A patent claim in which the resistor of the heater is formed in two parts, a low heat generation resistor and a high heat generation resistor, and the low heat generation resistor is located below the high heat generation resistor. The electric kettle according to item 5. (7) The heater has water level detection electrodes arranged externally at a predetermined interval from the lower end to the upper end,
A liquid level display device comprising a detection section that detects conduction and non-conduction between a lowest electrode and an upper electrode, and a drive circuit that drives a display element according to a signal from the detection section. An electric kettle according to claim 5 or 6.