JPH038208Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention is an electric pot, in particular, has a double wall structure, and forms a radiation prevention coating on the wall surface forming the space between the double walls. A double container in which the space is vacuum insulated (hereinafter referred to as a vacuum insulated double container)
Regarding electric pots consisting of.

(Prior Art) Conventionally, electric pots include those in which a closed mica heater is placed inside a container to directly heat water, etc. in the container, or a band heater is attached to the outer periphery of the bottom of the container. BACKGROUND ART Heat-retaining electric pots with a container wrapped around a heat insulating material such as glass wool are in widespread use. However, in the former case, increasing the watt density of the heater in order to downsize the heater leads to problems such as deterioration of the mica insulation, shortening the lifespan of the heater wire, and significantly lacking in heat retention.
In addition, the latter can use a large-capacity heater, but
Its heat retention performance is only about one-fifth that of a thermos flask,
There was a problem in that the power consumption required to keep warm was large, and the temperature of the contents would drop to about 80 degrees Celsius in less than an hour if the device was left unplugged.

To solve this problem, for example,
No. 43332 and Japanese Utility Model Application Publication No. 185135/1983, the pot body is made of a vacuum insulated double container, the bottom of which is made of a single wall, and a flat mica heater is attached to the bottom wall surface, or the pot body is A pot has been proposed in which a ceramic heater is attached to the inside of the pot body through a hole in the bottom to directly heat water or the like.

(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,
Similar to when a hole is formed in the metal exterior of a sealed mica heater, there is a risk of electrical leakage or electric shock.

(Means for Solving the Problems) As a means for solving the above problems, the present invention provides a ceramic heater disposed inside a vacuum insulated double container 1 consisting of an inner container 1a and an outer container 1b, as shown in the figure. In the electric pot, a cylindrical recess 2 is formed at the bottom of the inner container 1a of the vacuum insulated double container 1, and the ceramic heater 5 is provided with a corrosion-resistant ceramic heater 5 having a diameter smaller than the inner diameter of the cylindrical recess 2. A mounting bracket 1 is installed inside an exterior body 4 made of metal material to form a heater unit 3, and is provided at the bottom of the exterior body 4.
1 through a through hole formed coaxially with the recess 2 in the bottom of the double container 1 to form the cylindrical recess 2.
A sealing material 20 is provided between the side wall of the cylindrical recess 2 and the side wall of the heater unit 3 to form a sealed space 21 between the recess 2 and the heater unit 3. It is designed to form a

In the embodiment of the present invention, an annular projection 16 is provided at the bottom of the outer container 1b of the container 1 and protrudes downward coaxially with the cylindrical fitting 11, and between the annular projection 16 and the cylindrical fitting 11. A heat insulating material 15 is provided in the space formed.

In other embodiments, the ceramic heater 3
is in pressure contact with the buffer layer 8 by a coil-shaped or plate-shaped spring 12 disposed between the bottom wall surface of the exterior body 4 and the ceramic heater 3, and is in a state of non-contact with the side wall surface and the bottom wall surface of the exterior body 4. will be maintained.

In another embodiment, a recess 7a is provided in the bottom wall of the exterior body 4, an opening is formed in the recess 7a, and a cylindrical fitting 11 is attached to the opening.

Furthermore, in other embodiments, in order to absorb thermal deformation of the ceramic heater 5 and the buffer layer 8,
A recess is formed in the center of the surface of the buffer layer 8 that is in contact with the ceramic heater 5.

(Function) The electric pot according to the present invention has a sealing material 20 disposed at a position away from the mounting part 1
The heat conduction path leading to the outer container 1b is lengthened to reduce the temperature difference between the portion of the outer container 1b that is in contact with the atmosphere and the atmosphere, thereby suppressing heat radiation.

That is, a sealing gasket 13 is attached to a cylindrical fitting 11 provided at the bottom of the exterior body of the heater unit 3.
If the fitting 11 is inserted into the opening at the bottom of the container and fixed with the nut 14 from the outside of the container 1 after mounting, the hot water is filled up to the sealing part 13, so that the fitting 11 is inserted into the opening at the bottom of the container. The heat conduction path leading to the heater unit 3 becomes shorter, and it is inevitable that heat will dissipate to the outside through the cylindrical mounting bracket 11 and the container wall. A space 21 is provided between the heater unit 3 and the vacuum insulated double container 1 between the sealing material 20 and the mounting portion X by sealing with a sealing material 20 as far away as possible from It is.

In addition, by interposing the buffer layer 8 made of a soft, highly thermally conductive material between the exterior body 4 of the heater unit 3 and the ceramic heater 5, and attaching the ceramic heater 5, heat transfer is enhanced.
The heat of the ceramic heater 5 is absorbed and dissipated into the buffer layer 8 to prevent local overheating, and at the same time, the external thermal shock applied to the ceramic heater 5 is alleviated to prevent the occurrence of cracks. It is something.

Furthermore, a ceramic heater 5 is used as an electric heater.
By adopting this method, even if a hole is formed in the stainless steel exterior body 4 due to corrosion, the excellent heat resistance and insulation properties of the ceramic heater itself will be used to prevent deterioration of the insulation, leakage, and electric shock. It eliminates fear. In addition, liquid that has entered the exterior body,
By placing the ceramic heater 5 in a non-contact state with the side wall surface and bottom wall surface of the exterior body, even if the liquid content enters the interior of the exterior body, it is prevented from coming into contact with the ceramic heater 5.

In addition, by forming a recess 7a in the bottom wall of the exterior body and attaching the cylindrical fitting 11 to the opening provided in this recess, it is possible to prevent liquid from entering the exterior body if a hole is made in the exterior body 4. Even if the electric shock occurs, the liquid is collected in the recess 7a and flows out through the hole in the cylindrical fitting 11, thereby preventing electric shock and leakage.

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

FIG. 1 shows an embodiment of the electric pot according to the present invention, in which 1 is a vacuum insulated double container made of stainless steel;
A and 1b are the inner and outer containers, and 3 is a heater unit.

A recess 2 protruding downward is formed in the bottom of the inner container 1a of the vacuum insulated double container 1, and the recess 2 is slightly larger than the outer diameter of the exterior body 4 of the heater unit 3. There are 3 heater units in the facility.
It is arranged so that

The heater unit 3 basically consists of an exterior body 4.
and a buffer layer 8 bonded to the ceiling wall surface of the exterior body 4.
and a ceramic heater 5 brought into close contact with the buffer layer 8, and a cylindrical fitting 11 is attached to the bottom of the exterior body 4.

The exterior body 4 of the heater unit includes an upper member 6 formed of an aluminum-clad stainless steel plate.
and a bottomed cylindrical lower member 7 made of stainless steel. At the center of the lower member 7 is a flange 11 of a mounting bracket 11.
A recess 7a is formed which is deeper than the thickness of the recess 7a, and an opening 7b is provided in the recess 7a. The heater unit 3 has an upper member 6 that becomes the ceiling wall surface of the exterior body 4.
The ceramic heater 5 is bonded by applying silicone grease or the like to the surface of the buffer layer 8 made of aluminum which is clad-bonded to the surface (the inner surface in the figure) of the aluminum.
A buffer layer 8 is formed by a coil-shaped or plate-shaped spring 12.
The lower member 7 is pressed so that it does not come into direct contact with the lower member 7. Furthermore, the lead wire 9 is covered with a heat-resistant insulating tube 10, guided to the outside through a cylindrical fitting, the lower member 7 and the upper member 6 are set, and the joint surfaces of the two are welded, crimped or brazed while applying pressure. It is attached and integrated.

The ceramic heater 5 has a slightly smaller diameter than the buffer layer 8, and has a main heater installed inside it, but in addition to this main heater, it is also equipped with an auxiliary heater for keeping warm and an empty heating sensor. It may be.

The heater unit 3 having the above structure has its bottom fitting 11 passed through the bottom of the vacuum insulated double container 1 and fixed with a nut 14.
A seal ring 20 is attached to the lower part of the side wall of the exterior body 4 of the heater unit 3, and surrounds the attachment part X between the heater unit 3 and the vacuum insulated double container 1 at a position away from the attachment part to form a seal between the two. While sealing, a space 21 is formed between the exterior body 4 of the heater unit 3 and the vacuum insulated double container 1. In addition, a seal ring 13 is installed around the outer wall of the recess 7a of the exterior body 4 of the heater unit 3, so that even if the seal with the seal ring 20 becomes defective, water will still flow to the heater unit mounting part. It is designed to prevent intrusion. An annular projection 16 is formed at the bottom of the outer container 1b, and a space surrounded by the annular projection 16 is filled with a heat insulating material 15.

When using an electric pot with the above structure, when boiling water, the heat from the ceramic heater 5 is conducted to the exterior body 4 via the buffer layer 8, heating the water near the heater unit 3, and at the same time, part of the heat is transferred to the exterior body. However, since the heat conduction distance from the buffer layer 8 to the heater unit mounting part is long and the heat is in contact with water, the bottom wall of the inner container 1a is not exposed to high temperature. Therefore, since the inner container 1a is heated to a high temperature and the degree of vacuum does not decrease due to the release of gas contained in the metal material, there is no decrease in heat retention. In addition, when keeping warm water, the seal ring 20 seals the space between the heater unit 3 and the inner container 1a away from the heater unit attachment part X, and since a space is formed, the seal ring 20 contacts the hot water. The ability to increase the distance from the ring part to the heater unit attachment part and the fact that the bottom of the outer container 1b is shielded from the atmosphere by the heat insulating material 15 make it possible to extend the distance from the seal ring 20 to the outer container 1b.
Because the distance of heat conduction to the part of the body that comes into contact with the atmosphere is long, the heat dissipation due to heat conduction is significantly reduced.

By the way, when the seal ring 20 and heat insulating material 15 are removed and the distance from the seal ring 13 to the bottom opening tip of the vacuum insulated double container is approximately 20 mm, the temperature of the hot water inside is approximately 90°C. The temperature at the tip of the opening is approximately 56°C, but if only the seal ring 20 is attached with the insulation removed, the distance from the seal ring 20 to the tip X of the lower opening will be approximately 40 mm, and the tip of the opening will be temperature has dropped to approximately 47°C, reducing the difference from atmospheric temperature and improving heat retention. Furthermore, when the heat insulating material 15 was added, the distance (longitudinal cross-sectional distance) Y to the part where the outer container 1b contacts the atmosphere became 80 mm, and the temperature at that part decreased to 37°C, further improving heat retention.

Alternatively, a water temperature sensor may be disposed within the space of the lower member 7 so as to be able to detect the temperature at the bottom of the vacuum insulated double container where the liquid temperature in the vacuum insulated double container is the lowest due to convection.

(Effect of the invention) According to the invention, the heat retention of the vacuum insulated double container can be significantly improved. In addition, by adopting a heater unit with a structure in which a ceramic heater is placed in close contact with a buffer layer made of a metal material with good thermal conductivity provided inside the exterior body, the watt density of the ceramic heater can be increased and the heater unit can be made more compact. Therefore, it can be easily inserted and attached through the relatively small opening of the vacuum insulated double container. In addition, even if the stainless steel exterior body corrodes and has holes, 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 electrical leakage or electric shock, and there will be no water leakage. Since it flows out through the hole in the fitting, it does not stay inside the heater. Furthermore, the dry heating sensor, heat retention heater, and even water temperature sensor can be integrated, so no other parts are required.
Installation is also 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 showing the main parts of an electric pot according to the present invention. DESCRIPTION OF SYMBOLS 1... Vacuum insulation double container, 3... Heater unit, 4... Exterior body, 5... Ceramic heater, 6
... Upper member, 7 ... Lower member, 8 ... Buffer layer,
11...Mounting metal fittings, 12...Spring, 20...
Seal material (seal ring), 21...space.

Claims (1)

[Claims for Utility Model Registration] (1) In an electric pot comprising a vacuum insulated double container consisting of an inner container and an outer container, and a ceramic heater disposed inside the vacuum insulated double container, the bottom of the inner container of the vacuum insulated double container while forming a cylindrical recess in the
The ceramic heater is installed inside an exterior body made of a corrosion-resistant metal material having a smaller diameter than the inner diameter of the cylindrical recess to form a heater unit. fixing a heater unit within the cylindrical recess through a through hole formed coaxially with the recess;
An electric pot characterized in that a sealing material is disposed between the side wall of the cylindrical recess and the side wall of the heater unit to form a sealed space between the recess and the heater unit. (2) The electric pot according to claim 1, wherein the ceramic heater is attached to the ceiling wall of the exterior body through a buffer layer made of a metal material with good thermal conductivity. (3) An annular projection protruding downward coaxially with the cylindrical fitting is provided at the bottom of the outer container of the vacuum insulated double container, and a space formed between the annular projection and the cylindrical fitting is provided. An electric pot according to claim 1 or 2 of the utility model registration claim, which is filled with a heat insulating material. (4) The heater unit includes a spring that is disposed between the bottom surface of the ceramic heater and the bottom wall surface of the exterior body and presses the ceramic heater against the buffer layer, and the ceramic heater contacts the side wall surface and the bottom wall surface of the exterior body. An electric pot according to claim 1, 2, or 3 of the utility model registration claim, which is maintained in a non-contact state. (5) The electric pot according to any one of claims 1 to 4, which is a utility model, and has a recess in the center of the surface where the buffer layer of the heater unit contacts the ceramic heater. (6) The exterior body of the heater unit has a cylindrical recess protruding downward at the bottom thereof, and a mounting bracket is attached to the cylindrical recess, the scope of the utility model registration claims 1 to 5. An electric pot listed in any of the above. (7) A utility model according to claim 6, wherein a seal ring is disposed on the outer periphery of the cylindrical recess of the exterior body for sealing between the exterior body and the bottom of the vacuum insulated double container. Electric pot.