JP2534157B2 - Hot air electric heater - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hot-air type electric heater used as a cooking utensil or the like.

Conventional technology and its problems Conventionally, electric heaters used as cooking utensils or the like have coiled heating wires such as nichrome wires along a spiral groove formed on the upper surface of an inorganic insulator such as ceramic. Heat the object to be heated by the electric stove that is fitted and heats the object to be heated by the heat transfer and radiant heat from the heating wire, and the heat from the sheath heater composed of the heating wire embedded in the inorganic powder in the heat-resistant metal tube. There is an electric heating device to do. Furthermore, a halogen heater electric heater using a halogen lamp as a heat source, an electromagnetic induction cooker-based electromagnetic cooker, and the like are also used in various ways.

These electric heaters are gas cookers using combustion gas,
Although there is no danger such as gas burners, there is a problem that the heating temperature is lower than these and therefore cooking or the like requiring high temperature cannot be performed. Also, in these electric heaters,
In order to improve the heating efficiency, it is necessary to keep the electric heater and the object to be heated in contact with or close to each other, and improvement has been desired.

An object of the present invention is to solve the above problems and provide a hot-air type electric heater capable of heating an object to be heated in a non-contact state to a high temperature which cannot be obtained by the conventional electric heater.

Means for Solving the Problems The above-mentioned object of the present invention is to provide a heat-resistant and electrically insulating partition member that partitions and forms a large number of parallel through-holes, and a heating wire that passes through each through-path of the partition member. A housing that houses a partition member and a heating wire and has an air supply port on one end side and an air discharge port on the multi-end side of the through passage, and is attached to the housing so as to blow air from the air supply port to the air discharge port. And a heating fan, wherein the heating wire extends so that one or two linear portions are present with respect to one through passage. It

The object of the present invention is also to provide a heat-resistant and electrically insulating partition member that partitions and forms a large number of parallel through-passages, a heating wire that passes through each through-passage of the partitioning member, and the partitioning member and the heating wire. A housing having an air supply port on one end side and an air discharge port on the other end side of the through passage, and a blower attached to the housing so as to blow air from the air supply port to the air discharge port And the ratio of the area obtained by subtracting the cross-sectional area of the heating wire from the cross-sectional area of the through passage and the cross-sectional area of the heating wire is 1: 1 to 20: 1. Is achieved by the vessel.

In addition to the ratio, the relationship between the through passage and the heating wire may be such that one or two linear portions are present for one through passage.

It is preferable that the partition member is made of a sintered compact made of a high emissivity material containing quartz, ceramic, a silicate compound, a titanate compound, and a zirconate compound.

It is preferable that a rectifying grid body for rectifying the air flow by the blower is disposed between the partition member and the blower.

The heating wire may extend in a U-shape with respect to each of the through passages, and may be connected to one side of the through passages.

Function and Effect In the electric heater of the present invention, the heating wire is passed through each of a large number of through paths that penetrate the partition members having heat resistance and electrical insulation in parallel, and the air flow generated by the blower is the heating wire. Pass through each of the through paths that have been inserted in the same direction. This electric heater heats an object to be heated by contact with heated air blown out from the through passage and radiation from the surface of the partition member. Generally, the following relationship is established between the power consumption W (Kw) of the electric heater, the gas discharge port temperature T (° C), and the surface temperature T + t (° C) near the exit of the through passage in the partition member.

W × 860 = σ × {(T + t + 270) ⁴ −273 ⁴ } × ε × S + N × 28.8 / 22.4 × (a × T + b / 2 × T ² + c / 3 × T ³ ) σ: Stefan-Boltzmann constant 4.88 × 10 ^{− 8} ε: Emissivity S: Gas outlet area (m ² ) N: Gas flow rate (Nm ³ ; Gas temperature 0 ° C, 1 atm) a, b, c: Specific heat constant of gas where temperature is 0 ° C, Using 1 atm of air, power consumption W is 2 (Kw), temperature difference t is 200 (° C), emissivity ε
Is 0.5, the air outlet area is Sa =
0.005 (m ² ), Sb = 0.010 (m ² ), Sc = 0.015 (m ² ), Sd = 0.
The results shown in FIG. 4 can be obtained for the case of 020 (m ² ). As can be seen from FIG. 4, it is advantageous to reduce the air discharge port area S and reduce the discharge air amount N in order to obtain the discharge air heated to a high temperature.

On the other hand, in order to obtain high-temperature heated air, it is necessary to raise the temperature of the heating wire. That is, using a high temperature heating wire,
It is advantageous to obtain high-temperature discharge air by making the air discharge port small to reduce the amount of air passing through the heating wire. However, when the heating wire is used in this way, it melts and breaks easily and cannot be put to practical use.

The present invention solves such a technical problem as follows. That is, the heating wire is extended into a large number of through-passages formed by the heat-resistant partitioning member, and the radiant heat from the heating wire is absorbed not only by the air in the through-passage but also by the partitioning member. Since the heat transfer area of the partition member is extremely larger than that of the heating wire, a large amount of heat is transferred from the heated partition member to the air in the through path by radiation and conduction. As a result, the heat of the heating wire is continuously transmitted to the partition member that radiates heat by itself, and it is possible to avoid a temperature rise that would cause fusing.
As described above, the improvement of the heat transfer efficiency to the air in the through-passage and the improvement of the heat radiation from the heating wire coexist. Therefore, high-temperature discharge air can be obtained by the air flowing through the individual through passages.

In this case, if there are too many heating wires in the through passage, the heating wires will rise in temperature too much and melt down unless the air flow rate is increased more than necessary. Therefore, as one means for preventing this, it is assumed that the heating wire extends so that there is one or two linear portions for one through passage.

As another means for preventing the breakage, increasing the cross-sectional area of the through passage to some extent with respect to the cross-sectional area of the heating wire can be mentioned. On the other hand, if the cross-sectional area of the through passage is too large as compared with the cross-sectional area of the heating wire, it is not possible to obtain a fluid that has been sufficiently heated. Therefore, in this case, the ratio of the area obtained by subtracting the cross-sectional area of the heating wire from the cross-sectional area of the through passage and the cross-sectional area of the heating wire is 1: 1 to 20: 1.

EXAMPLES Examples of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 schematically shows a hot air electric heater according to an embodiment of the present invention. The electric heater includes a housing (1) having excellent heat insulation and heat resistance, which is made of ceramic or the like and has an air discharge port (1a) formed at an upper end and an air supply port (1b) formed at a lower end, and the housing. A heat-resistant and electrically insulating partition member (2) that partitions and forms a large number of through passages (2b) that are arranged in the vicinity of the air discharge port (1a) of (1) and that are parallel to each other between vertically facing side walls; From the lower end of the member (2) to each throughway (2
b) A heating wire (3) such as a nichrome wire which is placed inside the through passage (2b) and passes through the inside of the through passage (2b), and each through passage (2b) arranged near the air supply port (1b) of the housing (1). And a blower (4) for generating an air flow (indicated by an arrow in the figure) from the lower end to the upper end. As shown in FIGS. 2 and 3, the partition member (2) is formed by densely arranging a plurality of heat-resistant inorganic insulating tubes (2a) of the same shape in parallel to each other in the longitudinal direction. The holes of each insulating pipe (2a) form each of the above-mentioned through passages (2b). Each of the multiple insulating tubes (2a) forming the partition member (2) preferably has a high insulating property in order to prevent disconnection due to a short circuit of the heating wire (3). In this embodiment, quartz, ceramics are used. , A sintered compact made of a high emissivity material made of at least one insulating material such as a silicic acid compound, a titanic acid compound, a zirconic acid compound. However, the partition member (2) that constitutes these through-paths (2b) is an insulator obtained by coating an inorganic conductive material with an insulating material, or a conductive material and an inorganic insulating material interposed between the heating wire (3). It may be an insulator made of a conductive material. The heating wire (3) passing through the inside of each through-passage (2b) is inserted from the lower end of the through-passage (2b) and extends toward the upper end side, and is bent in the opposite direction at a position near the upper end, and the through-passage from the lower end. (2b) It is formed in a U-shape protruding to the outside, and this U-shape structure is continuously connected at its lower end. Between the partition member (2) and the blower (4) in the housing (1), as shown in FIG. 1, a heat-resistant material such as ceramic for rectifying the air flow sent from the blower (4). A sex rectifying grid (5) is provided. Further, in the electric heater of the present embodiment, the heating wire (3) put in the through passage (2b).
Heating wire surface temperature sensor (6) for detecting the surface temperature of, the discharge air temperature sensor (7) for detecting the temperature of the air discharged from the air discharge port (1a), these sensors (6), ( A temperature control device (8) for controlling the air temperature by controlling the air flow rate from the blower (4) and the power supply amount to the heating wire (3) in response to the detection signal from 7) is provided. . The temperature control device (8) has an air outlet (1
a) An outlet temperature setting device (9) for setting the target value of the temperature of the air discharged from a) and a heating wire temperature setting device (10) for setting the target value of the surface temperature of the heating wire (3). Based on the cooperation with the sensors (6) and (7), the surface temperature of the heating wire (3) and the air temperature discharged from the air discharge port (1a) are maintained at the set temperature.

In the electric heater of the present invention configured as described above, as shown in FIG. 1, the airflow generated by the blower (4) flows along the inside of the housing (1) and the rectifying grid body (5). Is rectified by and passes upward through each through passage (2b) of the partition member (2) containing the heating wire (3). The heating wire (3) generates heat based on the power supply from the temperature control device (8), and the partition member (2) is heated to a high temperature by the heating wire (3). The air passing through each through passage (2b) of the partition member (2) is heated by the heating wire (3) when passing through the passage.
Also, the temperature is raised by both heat transfer and radiant heat from the partition member (2) having a large heat transfer area, and the particles are sequentially discharged from each through passage (2b) and come into contact with an object to be heated (not shown). The heated object is heated to a high temperature.

In the electric heater of the present invention, the temperature of the discharge air can be made extremely high in a short time. For example, when 2 Kw of electric power is supplied to the heating wire (3) by using the heating device having the above configuration, the surface temperature of the heating wire (3) is about 1100 after about 5 minutes.
The temperature was raised to ℃ and the discharge air temperature became about 800 ℃. In this state, when a pan with 1.5 liters of water was put on the air outlet, it boiled after about 8 minutes. As described above, according to the electric heater of the present invention, it is possible to heat the object to be heated to a high temperature in a short time, and not to heat by heat transfer from the heating wire as in the conventional electric heater, but to contact with discharge air. Since the heating is based on, non-contact heating can be performed.

In the above embodiment, the partition member is composed of a large number of densely arranged inorganic insulating tubes, but the invention is not limited to this. For example, inorganic materials such as ceramics are arranged in a grid pattern or in a grid pattern. It may be a shaped insulator.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional side view schematically showing a hot air electric heater according to an embodiment of the present invention, FIG. 2 is a plan view showing a partition member thereof, and FIG. 3 is a second view. 4 is a cross-sectional view taken along the line I-I of FIG. 4, and FIG. 4 is a graph showing the relationship between the discharge air amount and the discharge air temperature in four types of air discharge port areas. (1) …… Housing (1a) …… Air discharge port (1b) …… Air supply port (2) …… Partition member (2a) …… Inorganic insulation pipe (2b) …… Penetration path (3) …… Electrical Heat wire (4) …… Blower (5) …… Rectifier grid (6) …… Heating wire surface temperature sensor (7) …… Discharged air temperature sensor (8) …… Temperature control device (9) …… Discharge port temperature Setting device (10): Heating wire temperature setting device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Taizo Imoto 6-2-6 Iwata-cho, Higashi-Osaka City, Osaka Prefecture (72) Inventor Yoshihiko Yamamoto 2-34-1, Honjo Higashi, Kita-ku, Osaka City, Osaka Prefecture (72) Inventor Takashi Shimono, 2-3, 41 Honjo Higashi, Kita-ku, Osaka, Osaka, Japan Kinden Co., Ltd. (72) Minoru Yoshida, 2-3-4, Honjo-Higashi, Kita-ku, Osaka, Osaka, Japan (56) Reference JP-A 61-114022 (JP, A) Actually opened 62-85804 (JP, U) Actually opened 62-85803 (JP, U)

Claims (5)

(57) [Claims] 1. A heat-resistant and electrically insulating partition member for partitioning and forming a large number of parallel through-passages, a heating wire passing through each through-passage of the partitioning member, the partitioning member and the heating wire being accommodated in the through-passage. A housing having an air supply port on one end side of the passage and an air discharge port on the other end side, and a blower attached to the housing so as to blow air from the air supply port to the air discharge port, The hot-air type electric heater, wherein the heating wire extends so that one or two linear portions are present with respect to one through passage. 2. A heat-resistant and electrically-insulating partition member for partitioning and forming a large number of parallel through-passages, a heating wire passing through each through-passage of the partitioning member, the partitioning member and the heating wire being accommodated in the through-passage. A housing having an air supply port on one end side of the passage and an air discharge port on the other end side, and a blower attached to the housing so as to blow air from the air supply port to the air discharge port, The hot-air type electric heater, wherein the ratio of the area obtained by subtracting the cross-sectional area of the heating wire from the cross-sectional area of the through passage to the cross-sectional area of the heating wire is 1: 1 to 20: 1. 3. The partition member is made of a sintered compact made of a high emissivity material containing quartz, ceramics, silicic acid compounds, titanic acid compounds and zirconic acid compounds. Hot air electric heater. 4. A rectifying grid body for rectifying an air flow by the blower is arranged between the section member and the blower. Hot air electric heater. 5. The hot air electric heater according to claim 1, wherein the heating wire extends in a U shape with respect to each of the through passages.