JPH034178Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention is a heater for electric pots, in particular, a double container (hereinafter referred to as vacuum This invention relates to a heater suitable for directly heating the liquid inside a pot body consisting of a heat-insulating double container.

(Prior art) Conventionally, closed-type mica heaters, which are placed inside a container and directly heats the water, etc. inside the container, have been widely used as heaters for electric pots. Increasing the density causes deterioration of the mica insulation, shortens the lifespan of the heater wire, and causes problems in that this type of electric pot lacks heat retention. For this reason, in recent years, in addition to wrapping the container with a heat insulating material such as glass wool to provide heat retention, a band heater made of a mica heater formed in a band shape is attached to the lower outer periphery of the container.
Heat-retaining electric pots are widely used in practice, in which a heater wire with a large wattage heats and boils while a heater wire with a small wattage maintains heat.

However, the heat retention performance of this type of thermal electric pot is only about one-fifth of that of a vacuum bottle, and the power consumption required to keep it warm is large, and if the electric pot is left unplugged, the temperature of the contents will drop within an hour. There is a problem that the temperature drops to about 80℃.

In order to solve this problem, we used a vacuum insulated double container as the pot body with a single-walled bottom and a flat mica heater attached, or a ceramic heater was installed through a hole in the bottom of the pot body. A pot that is attached to the inside of the pot body and directly heats water, etc. has been proposed (for example, Japanese Utility Model Publication No. 43332/1983;
Publication No. 185135).

(Problem that the invention aims to solve) However, since the flat mica heater requires a single wall structure at the bottom of the container, the inherent heat retention performance of the vacuum insulated double container is significantly impaired.
In addition, ceramic heaters may crack due to local temperature increases due to dry heating or thermal shock when replenishing cold water during heat retention, and as a result,
Currently, this method has not been put into practical use because there is a risk of leakage or electric shock, similar to when a hole is formed in the metal exterior of a sealed mica heater.

Therefore, the present invention eliminates the risk of electrical leakage and electric shock.
To provide a heater for an electric pot that is resistant to thermal shock when heated dry and can be attached without greatly deteriorating the inherent heat retention performance of a vacuum insulated double container.

(Means for Solving the Problems) The present invention uses a ceramic heater as the heater in an electric pot heater that is placed inside the pot body and directly heats the liquid, and the exterior body housing the heater is made of stainless steel or the like. A thick buffer layer made of a corrosion-resistant metal material and made of a metal material with good thermal conductivity (e.g., aluminum, copper) is hot-bonded to the ceiling wall surface of the exterior body, and a ceramic heater is pressed onto the buffer layer with a spring. It was designed to bring them into close contact with each other.

In an embodiment of the present invention, the ceramic heater is pressed against the buffer layer by a spring disposed between the bottom wall surface of the exterior body and the ceramic heater, and is not in contact with the side wall surface and the bottom wall surface of the exterior body. maintained.

In another embodiment of the present invention, a recess is provided in the bottom wall of the exterior body, an opening is formed in the recess, and a cylindrical fitting is attached to the opening.

In another embodiment of the present invention, a recess is formed in the center of the surface of the buffer layer in contact with the ceramic heater in order to absorb thermal deformation of the ceramic heater and the buffer layer.

(Function) When the electric pot heater according to the present invention is energized, the heat is conducted to the exterior body 4 through the thick buffer layer 8 having good thermal conductivity. The material forming the buffer layer 8 is soft and its flatness can be easily achieved by cutting, thereby improving adhesion to the ceramic heater and increasing heat transfer. Therefore, even when the ceramic heater 5 is not heated, the heat of the ceramic heater 5 is absorbed and dissipated by the buffer layer 8 because the buffer layer 8 is a good thermal conductor and has a large heat capacity.
Local overheating of the area is prevented. In addition, the large heat capacity and high strength of the buffer layer 8 combine to reduce thermal deformation of the contact surface, and even if the heater is rapidly cooled by replenishing cold water when energizing, the buffer layer 8 alleviates thermal shock. Ceramic heater 5
This prevents cracks from occurring.

Furthermore, even if the exterior body 4 is made of stainless steel, holes may form due to corrosion, but even in this case, the ceramic heater itself has excellent heat resistance and has an insulating function, so insulation deterioration does not occur and electrical leakage does not occur. There is no risk of electric shock. Note that the liquid that has entered the interior of the exterior body does not wet the ceramic heater because the ceramic heater is in a non-contact state with the side wall surface and bottom wall surface of the exterior body.

Further, a recess 7a is formed in the bottom wall of the exterior body 4, and the cylindrical mounting bracket 1 is inserted into the opening 7b provided in this recess.
1 is attached, liquid that enters the outer case due to a hole in the outer case collects in the recess 7a and flows out through the hole in the cylindrical fitting 11.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an embodiment in which the electric pot heater according to the present invention is applied to a heat-retaining electric pot, in which 1 is the exterior body of the electric pot, 2 is a vacuum-insulated double container made of glass or stainless steel, and 3 is a vacuum-insulated double container made of glass or stainless steel. It's a heater.
The heater 3 basically consists of an exterior body 4 and an exterior body 4.
It is composed of a buffer layer 8 hot-bonded to the ceiling wall surface of the ceiling, and a ceramic heater 5 that is brought into close contact with the buffer layer 8.

The exterior body 4 is composed of an upper member 6 formed from an aluminum-clad stainless steel plate, and a lower member 7 separately formed by press working stainless steel. The heater 3 is constructed by applying silicone grease or the like to the surface of a buffer layer 8 made of aluminum that is clad-bonded to the surface (inner surface in the figure) of the upper member 6, which becomes the ceiling wall surface of the exterior body 4, and then bringing the ceramic heater 5 into contact with the surface. , a heat-resistant insulating tube 10 is placed over the lead wire 9, and a mounting bracket 11 and a coil spring (or plate spring) 12 are placed on a lower member 7 which is separately formed by pressing a stainless steel plate. 7 and the upper member 6, and are integrated by welding, caulking, or brazing the joint surfaces while applying pressure.

In order to absorb thermal deformation, the buffer layer 8 has a recess 8a formed in the center of the surface in contact with the ceramic heater 5. The ceramic heater 5 has a slightly smaller diameter than the buffer layer 8, and has a main heater formed inside it, but in addition to this main heater,
It may be formed with an auxiliary heater for keeping warm or a dry heating sensor. The ceramic heater 5 is pressed against the buffer layer 8 by a coil spring (or plate spring) 12 so as not to come into direct contact with the lower member 7. In addition, a cylindrical insulator 17 is integrally formed at the bottom of the ceramic heater, and a lead wire 9 with an insulating tube 10 is passed through this hole, and a molding material 16 such as silicone rubber RTV is used to further improve water resistance. It is sealed.

Note that a mounting bracket 1 is installed in the center of the lower member 7.
A recess 7a deeper than the thickness of the flange 11a of No. 1 is formed, and an opening 7b is provided in the recess 7a. Furthermore, a water temperature sensor 15 is disposed in the space of the lower member 7, and is configured to detect the temperature at the bottom of the vacuum insulated double container where the liquid temperature in the double vacuum insulated container is the lowest due to convection.

When installing the heater for electric pots having the above structure, the fitting 11 of the heater 3 may be fixed via the gasket 13 to the opening provided at the bottom of the vacuum insulated double container 2 by tightening it with a fixing nut 14.

(Effects of the invention) The heater for electric pots according to the invention can have a compact shape because the watt density of the ceramic heater can be increased, and can therefore be easily inserted through the relatively small opening of a vacuum insulated double container. Can be installed. In the unlikely event that the stainless steel exterior body corrodes and has a hole, it will be insulated by the ceramic layer of the ceramic heater itself, and the lead wires are also insulated, so there will be no leakage or electric shock, and there will be no leakage. Since it flows out through the hole in the fitting, it does not remain in the mica. Furthermore, since the dry-heat sensor, heat retention heater, and even water temperature sensor can be integrated, no other parts are required and installation is easy. In addition, since the opening at the bottom of the vacuum insulated double container can be small enough to pass the mounting hardware through, it has excellent effects such as minimizing the drop in heat retention performance of the vacuum insulated double container itself. .

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a heat-retaining electric pot to which the heater for electric pots according to the present invention is applied, and FIG. 2 is an enlarged sectional view of the main parts thereof. DESCRIPTION OF SYMBOLS 1... Exterior body of electric pot, 2... Vacuum insulation double container, 3... Heater, 4... Exterior body, 5... Ceramic heater, 6... Upper member, 7... Lower member, 8... Buffer layer, 8a... recess, 11... mounting bracket, 12... coil spring.

Claims (1)

[Claims for Utility Model Registration] (1) An exterior body made of a corrosion-resistant metal material, and a thick buffer made of a highly thermally conductive metal material that is integrated with the ceiling wall inside the exterior body by hot bonding. A heater for an electric pot, comprising: a ceramic heater layer; and a ceramic heater disposed inside the exterior body and pressed against the buffer layer by a spring so as to be brought into close contact with the buffer layer. (2) The spring is disposed between the bottom surface of the ceramic heater and the bottom wall surface of the exterior body, so that the ceramic heater is maintained in a non-contact state with the side wall surface and the bottom wall surface of the exterior body. A heater for an electric pot according to claim 1 of the patent registration claim. (3) The electric pot according to claim 1 or 2, wherein the bottom wall of the exterior body has a recess, and a cylindrical fitting is attached to the opening formed in the recess. heater. (4) Utility model registration claim No. 1 in which the buffer layer has a recess in the center of the surface in contact with the ceramic heater
A heater for an electric pot according to any one of items 1 to 3.