JP2929844B2 - Electric heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric heater used for an electric cooker or an electric heater.

[0002]

2. Description of the Related Art Most of conventional electric heaters used for cookers and heaters are sheathed heaters, quartz tube (or heat-resistant glass tube) heaters, mica heaters, and the like.
Or a nichrome wire heater.

[0003] A conventional electric heater will be described below. As shown in FIG. 8, the sheathed heater is formed in a rod shape with a heating wire 11, an insulating material 12, a sealing material 13, and a protective tube 14. At the time of energization, the surface temperature of the protection tube 14 is 700 to 8
The temperature becomes 00 ° C. and the object to be heated is heated.

The quartz tube heater uses a quartz tube as the protection tube 14, and its structure is basically the same as that of the sheathed heater.

In the mica heater, a heating wire 16 is wound around a mica plate 15 as shown in FIG.
When energized, the heating wire heats the mica plate to about 500 ° C., and the object to be heated is heated by the secondary radiation of the mica plate.

The nichrome wire heater has a structure in which a spiral nichrome wire 19 is fixed in a groove of a sintered body 20 as shown in FIG.

[0007]

However, in the sheathed heater and the quartz tube heater, the electric resistance heating element has a tubular shape, so that the projected radiation area cannot be large, and the radiation is transmitted in all directions (360 degrees). Therefore, there is a problem that the amount of radiation to the object to be heated is small, and the radiation amount differs between a portion opposed to the heater and a portion not facing the heater, resulting in poor distribution. Further, the sheathed heater has a problem that the protective tube is made of metal, and when used for a heater for a cooker, the metal tube is corroded by a corrosive substance such as salt at a high temperature. In addition, the mica heater has a problem that the radiation temperature from the mica plate is 500 ° C., which is lower than that of other heaters, so that the radiation amount is small.

On the other hand, the nichrome wire heater has the same problem as the sheathed heater because it is wound in a solenoid coil shape, and the heat of the heating wire is conducted to the sintered body,
In the case of a general box-type cooker having a poor start-up characteristic and a heater disposed on the upper surface, there is a problem that the heating wire hangs down due to heat. In addition, since the heating wire was bare, there was a problem that the wire corroded.

The present invention has been made to solve the above problems, and has as its first object to obtain a high radiation type heater having a high radiation amount and good rising characteristics.

A second object is to provide a safe heater that prevents the heating wire from sagging.

[0013] A third object is to obtain a heater having high durability.

[0012]

In order to achieve the first object, the present invention uses a tape-shaped electric resistance heating element and has a fixing beam or a fixing projection for holding the heating element. In addition, the electric resistance heating element is sandwiched between insulators having holes at the portion corresponding to the radiation surface.

According to another aspect of the present invention, a tape-shaped electric resistance heating element is provided with a fixing beam or a fixing projection for preventing the electric resistance heating element from hanging down. A configuration in which the fixing beam supports the tape-shaped electric resistance heating element by being sandwiched between two perforated insulators each having a hole in a portion corresponding to a radiation surface of the resistance heating element, or a tape-shaped electric resistance heating element. An insulator having a hole in a portion corresponding to a radiation surface of the electric resistance heating element so as to have a fixing beam or a fixing projection for preventing the electric resistance heating element from hanging down; A configuration in which the fixing beam supports the tape-shaped electric resistance heating element by being sandwiched between a fixing beam or a grooved heat insulating material having a fixing projection on a portion corresponding to a radiation surface of the heating element. did Than it is.

In order to achieve the third object, the present invention is configured such that the radiation surface of the tape-shaped electric resistance heating element of the electric heater having the above-mentioned configuration is covered with a heat-resistant material made of heat-resistant glass or ceramic. Further, the distance between the heater wire and the heat-resistant material is set longer than the sagging of the heater wire due to thermal expansion so that the tape-shaped electric resistance heating element does not contact the heat-resistant material.

[0015]

According to the present invention, a foil-shaped tape-shaped electric resistance heating element having a small heat capacity and a large radiating area is used in the present invention, so that the heating property of the heating element is quickened and radiation from the heating element can be used as it is. The amount of radiation is obtained. In addition, the configuration in which the tape-shaped electric resistance heating element is supported only by the fixed beams of the insulator reduces the contact area between the tape-shaped electric resistance heating element and the insulator, reduces the amount of heat transfer by contact heat transfer, and reduces the effective radiation surface. Since it is large, fast heat and high radiation can be obtained, and sagging due to thermal expansion of the tape-shaped electric resistance heating element is prevented.

Further, since the heat-resistant glass is configured to protect the heating wire, corrosion of the electric resistance heating element by a substance such as salt can be prevented. Further, since the tape-shaped electric resistance heating element is prevented from hanging down and coming into contact with the heat-resistant material, the temperature of the tape-shaped electric resistance heating element is prevented from lowering due to the contact, and the radiation amount is prevented from lowering.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 In FIGS. 1, 2 and 3, 1 is a tape-shaped electric resistance heating element, 3 is an insulator with holes, and 5 is a heat insulating material. As shown in FIG. 2, the thickness of the foil-shaped electric resistance heating element 1 is several tens μm.
m and a width of 5 to 7 mm. Compared to a sheathed heater or a quartz tube heater, the heat capacity is extremely small because it is made of metal only, and the projected radiation area is 3 to 6 times that of a tape shape. Therefore, quick heat and high radiation can be obtained.

As shown in FIGS. 1 and 3, the tape-shaped electric resistance heating element 1 has a hole at a portion corresponding to the radiation surface 2 of the tape-shaped electric resistance heating element 1 so as to have a fixed beam 4. Between the tape-shaped electric resistance heating element and the insulator is small, the amount of heat transfer by contact heat transfer is reduced, and the quick heat property is improved. The radiation amount can be obtained, and sag due to thermal expansion can be prevented.

Embodiment 2 FIG. 4 shows another embodiment of the present invention. 1 is a tape-shaped heating element, 3 is an insulator with a hole, and 6 is a heat insulating material with a groove. As in the first embodiment, the tape-shaped electric resistance heating element 1 has a thickness of several tens of μm and a width of 5 to 7 mm, so that it is possible to obtain fast heat and a high radiation amount.

Further, the tape-shaped electric resistance heating element 1 comprises:
The tape-shaped electric resistance heating element 1 has a fixing beam 3.
Insulator 3 with a hole in a portion corresponding to radiation surface 2 of
And the tapered electrical resistance heating element is sandwiched between the electrical resistance heating element 1 and a grooved heat insulating material 6 having a groove so as to have the fixing beam 4 at a portion corresponding to the radiation surface 2 of the electric resistance heating element 1. By supporting, the amount of heat transfer due to contact heat transfer is reduced, a quick heat property and a high radiation amount are obtained, and the sag of the electric resistance heating element 1 due to thermal expansion can be prevented.

Embodiment 3 FIG. 5 shows another embodiment of the present invention. 1 is a tape-shaped electric resistance heating element, 7 is an insulator with a hole, and 8 is a fixing projection.
As in the case of the first and second embodiments, a foil-shaped electric resistance heating element in the form of a foil can be used to obtain quick heat and a high radiation amount.

Further, the tape-shaped electric resistance heating element 1 comprises:
The tape-shaped electric resistance heating element 1 is supported only by the fixing projections by being sandwiched between two insulators 7 with holes formed in the portion corresponding to the radiation surface 2 so as to have the fixing projections 8. In addition, the contact area between the tape-shaped electric resistance heating element and the insulator is small, the amount of heat transfer by contact heat transfer is reduced, so that quick heat and high radiation can be obtained, and sag due to thermal expansion can be prevented.

Embodiment 4 FIG. 6 shows another embodiment of the present invention. 1 is a tape-shaped electric resistance heating element, 3 is an insulator with a hole, 4 is a fixing beam, and 9 is heat resistant glass.

The above structure is the same as the electric heater of the first embodiment except that the radiation surface 2 of the tape-shaped electric resistance heating element 1 is covered with a heat-resistant glass 9.
Because of its good heat ray transmittance, it is possible to obtain a high radiation amount and to prevent the electric resistance heating element from sagging.
As described above, since the radiation surface 2 of the tape-shaped electric resistance heating element 1 is covered with the heat-resistant glass 9, it is possible to prevent the electric resistance heating element from being corroded by salt during food preparation.

In the electric heater having the structure of the second embodiment, the same effect can be obtained even when the radiation surface 2 of the tape-shaped electric resistance heating element 1 is covered with heat resistant glass. Similar effects can be obtained even when a ceramic plate having good heat ray transmission properties is used instead of the heat-resistant glass 6.

Embodiment 5 FIG. 7 shows another embodiment of the present invention. 1 is a tape-shaped electric resistance heating element, 7 is an insulator with a hole, 8 is a fixing projection, 9 is a heat-resistant glass, and 10 is a heat insulating material with a groove. The above configuration uses a foil-shaped tape-shaped electric resistance heating element as in the case of the first embodiment, so that it is possible to obtain quick heat and a high radiation amount. In addition, the tape-shaped electric resistance heating element 1 has a hole-formed insulator 3 having a hole corresponding to the radiation surface 2 of the tape-shaped electric resistance heating element 1 so as to have a fixing projection 3. The fixing projection supports the tape-shaped electric resistance heating element by being sandwiched by a grooved heat insulating material 10 having a groove having a fixing projection 8 at a portion corresponding to the radiation surface 2 of the heating element 1. The amount of heat transfer due to heat transfer is reduced, so that quick heat and a high radiation amount can be obtained, and the electric resistance heating element 1 can be prevented from sagging due to thermal expansion. Furthermore, the radiation surface 2 of the tape-shaped electric resistance heating element 1 is covered with heat-resistant glass 9, so that corrosion of the electric resistance heating element due to salt during food cooking can be prevented. The tape-shaped electric resistance heating element 1
The distance between the heat-resistant glass 9 and the heat-resistant glass 9 is determined by the amount of sag of the tape-shaped electric resistance heating element 1 due to thermal expansion. The sagging amount dt of the tape-shaped electric resistance heating element is Lp, the linear expansion coefficient of the tape-shaped electric resistance heating element is α,
Assuming that the room temperature is T1 and the temperature of the tape-shaped electric resistance heating element is T2, it is approximated by (Equation 1).

[0028]

(Equation 1)

Therefore, by making the distance between the tape-shaped electric resistance heating element 1 and the heat-resistant glass 9 larger than the sagging amount dt calculated by (Equation 1), the tape-shaped electric resistance heating element comes into contact with the heat-resistant glass. And the radiation amount can be prevented from decreasing due to a decrease in the heater wire temperature. For example, the pitch of the fixing protrusions is 8.5 mm, the material of the tape-shaped electric resistance heating element is stainless steel, and the temperature is 8 mm.
In the case of the electric heater at 00 ° C., the amount of sag is 1 mm. When the distance between the tape-shaped electric resistance heating element 1 and the heat-resistant glass 9 is 1 mm or more, the tape-shaped electric resistance heating element does not contact the heat-resistant glass.

[0030]

According to the electric heater of the present invention as described above, the following effects can be obtained. (1) Since a tape-shaped electric resistance heating element having a small heat capacity and a large radiation area is used, a rapid heat property and a high radiation amount can be obtained. (2) a two-hole insulator having a hole in a portion corresponding to a radiation surface of the tape-shaped electric resistance heating element so that the tape-shaped electric resistance heating element has a fixing beam or a fixing projection;
Or it is supported and fixed by being sandwiched between a grooved heat insulating material having a fixing beam or a fixing projection on a portion corresponding to the radiation surface of the holed insulator and the tape-shaped electric resistance heating element, The amount of heat transfer due to contact heat transfer is reduced, so that quick heat and high radiation can be obtained, and sag due to thermal expansion can be prevented. (3) Since the radiation surface of the tape-shaped electric resistance heating element of the electric heater is covered with a heat-resistant material made of heat-resistant glass or ceramic, corrosion of the electric resistance heating element by a substance such as salt can be prevented. Furthermore, if the distance between the heater wire and the heat-resistant material is greater than the sagging of the heater wire due to thermal expansion, the tape-shaped electric resistance heating element does not contact the heat-resistant material, preventing the temperature of the tape-shaped electric resistance heating element from decreasing,
High radiation is obtained.

[Brief description of the drawings]

FIG. 1 is an assembly view showing a configuration of an electric heater according to an embodiment of the present invention.

FIG. 2 is a perspective view of a tape-shaped electric resistance heating element according to one embodiment of the present invention.

FIG. 3 is a perspective view of the electric heater in the embodiment of FIG.

FIG. 4 is an assembly view showing a configuration of an electric heater according to another embodiment of the present invention.

FIG. 5 is an assembly view showing a configuration of an electric heater according to another embodiment of the present invention.

FIG. 6 is an assembly view showing a configuration of an electric heater according to another embodiment of the present invention.

FIG. 7 is an assembly view showing a configuration of an electric heater according to another embodiment of the present invention.

FIG. 8 is a sectional view of a conventional sheathed heater.

FIG. 9 is a perspective view of a conventional mica heater.

FIG. 10 is a perspective view of a conventional nichrome heater.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 tape-shaped electric resistance heating element 2 radiating surface 3 insulator with hole 4 fixing beam 5 heat insulator 6 heat insulator with groove 7 insulator with hole 8 fixing protrusion 9 heat resistant glass 10 heat insulator with groove

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H05B 3/20 309 H05B 3/84

Claims (6)

(57) [Claims] 1. A hole is formed in a portion corresponding to a radiation surface of the electric resistance heating element so as to have a tape-shaped electric resistance heating element and a fixing beam for preventing the electric resistance heating element from hanging down. An electric heater comprising a plurality of insulators with holes and a heat insulating material, wherein the fixing beam supports the tape-shaped electric resistance heating element by sandwiching the tape-shaped electric resistance heating element with the insulating substance with holes. . 2. A hole is formed in a portion corresponding to a radiation surface of the electric resistance heating element so as to have a tape-shaped electric resistance heating element and a fixing projection for preventing the electric resistance heating element from hanging down. An electric heater comprising a plurality of insulators with holes and a heat insulating material, wherein the fixed beam supports the tape-shaped electric resistance heating element by sandwiching the tape-shaped electric resistance heating element between the insulating bodies with holes. 3. A hole formed in a portion corresponding to a radiation surface of the electric resistance heating element so as to have a tape-shaped electric resistance heating element and a fixing beam for preventing the electric resistance heating element from hanging down. And a heat insulating material with a groove dug so as to have a fixed beam in a portion corresponding to a radiation surface of the electric resistance heating element, wherein the tape-shaped electric resistance heating element and An electric heater having a configuration in which the fixed beam supports the tape-shaped electric resistance heating element by being sandwiched between the grooved heat insulating materials. 4. A hole formed in a portion corresponding to a radiation surface of the electric resistance heating element so as to have a tape-shaped electric resistance heating element and a fixing projection for preventing the electric resistance heating element from hanging down. And a heat insulating material with a groove formed by digging a groove so as to have a fixing projection at a portion corresponding to a radiation surface of the electric resistance heating element. An electric heater having a configuration in which the fixing beam supports the tape-shaped electric resistance heating element by being sandwiched between the tapered heat insulating material. 5. The electric heater according to claim 1, wherein a radiation surface of the tape-shaped electric resistance heating element is covered with a heat-resistant material. 6. The electric heater according to claim 5, wherein the distance between the heater wire and the heat-resistant material is set to be longer than the sagging of the heater wire due to thermal expansion so that the tape-shaped electric resistance heating element does not contact the heat-resistant material.