JPS6161391A - Infrared heater - 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] [Technical field of invention] The present invention relates to an infrared heater.

[Technical background of the invention and its problems]

Infrared heaters used in electric stoves have a coil-shaped heater element inserted inside a quartz tube.Electricity is applied to the heater element to generate heat, and the quartz tube is heated by the heater element and emits infrared rays. It is generated and radiates from above.

In this infrared heater, in order to emit a large amount of infrared rays, it is necessary to increase the temperature of the heater element. For this purpose, each winding part of the heater element in the form of a coil is brought into close contact with each other to form a tight winding.
I am using it at a high temperature.

Furthermore, infrared heaters are particularly required to be used as vertically mounted heaters. In other words, infrared electric heaters are generally used as horizontal panels with heater elements arranged horizontally, but in this case, the heat dissipation by the heater elements is not carried out along the direction of a person's height, making it difficult to provide efficient heating. I can't do it. On the other hand, if the heater element is arranged vertically in the vertical direction, the heat radiated by the heater element is carried out in the direction of the human height, so that rational and efficient heating can be performed. In this case, the heater element may sag due to its own weight, resulting in an accident such as a short circuit and disconnection, so it is necessary to prevent this accident. For this purpose, it is required that short circuits do not occur even when the heater element f is at O and is pressed by the coil's own weight.

However, in order to avoid short circuits even when the coils are tightly wound in response to these demands, it is necessary to ensure complete electrical insulation from each other while each winding part of the heater element coil is tightly wound. be. If the insulation between the windings of the coil is poor, short circuits may occur between the windings and damage may occur, making it difficult to form the heater element in a tightly wound manner.

Conventionally, an infrared heater uses a heater element t made of a nickel-chromium alloy wire. In this case, the wire made of 2.Kel-chromium is oxidized to form an oxide film on the surface of the wire to insulate each winding portion of the heater element. However, the oxidized film of the nickel-chromium alloy has the drawback that it has poor insulation properties and is easily peeled off, making it impossible to ensure reliable and stable insulation between each winding portion of the heater element. For this reason, it has traditionally been difficult to form the coil of the heater element in a tightly wound manner, and we have realized the need to increase the amount of infrared radiation in the infrared heater and to use the infrared heater in a vertical position. I couldn't do it.

[Purpose of the invention]

The present invention has been made based on the above circumstances, and provides an infrared heater that can be installed vertically and can dramatically improve heating performance, and can increase the amount of infrared radiation. The purpose is to

[Summary of the invention]

The infrared heater of the present invention has a chromium-containing surface oxide.
It is characterized by comprising a coil-shaped heater element made of an aluminum-iron alloy, and a quartz tube into which the heater element is inserted. The chromium-aluminum-iron alloy forming the heater element preferably has a composition ratio of 10 to 30% chromium and 1 to 12% aluminum in terms of t-weight i%. That is, chromium-aluminum-
Iron alloys form a film on the surface that is mainly made of aluminum oxide, which is strong and has excellent insulating properties.This ensures complete electrical insulation between each winding of the heater element coil. It can be used by tightly wrapping it. This oxide film is densely formed mainly of α-At203, but when titanium and gold are added, α-A
Ti exists as At2TiO5 in t203 and α-A
The t203 coating is made even more dense. Also, Tl and Zr f
When added in combination, Ti and Zr cause internal oxidation in a composite manner, forming an internal oxidation layer between the surface oxidation layer and the base metal, thereby improving the adhesion of the surface oxidation layer. At this time, Hf, Y, Ce are elements that have the same function as zr.
, La et al.

In order to ensure workability, one or more of the above-mentioned additive elements (Ti, Zr, Hf, Y, Ce, La) should be added in an amount of 2% by weight or less, and further 0.1 to 1.5%.
Weight percent is preferred. The thickness of the oxide layer is preferably 10 to 70 μm, more preferably 20 to 40 μm, because if it is too thick, it will easily peel off, and if it is too weak, it will be difficult to obtain insulation.

By the way, the dense oxide film described above can be obtained by high-temperature oxidation treatment. The conditions are such that oxidation is carried out at 1100° C. to 1350° C. in the air or in wet hydrogen for 0.5 hours or more (industrially, 1 to 5 hours is preferred).

[Embodiments of the invention]

An embodiment of the present invention illustrated in the drawings will be described below.

The drawing shows a vertical infrared heater that is an embodiment of the present invention. In the figure, 1 is a coil-shaped heater element, 2 is a quartz tube into which the heater element 1 is inserted, 3 is a terminal connected to both ends of the heater element 1, and 4 is a quartz tube 2
This is a closure material in which the openings at both ends are completely closed and terminals 3 are attached.

The heater element 1 is formed by forming a wire into a coil shape, and each winding portion of the coil is tightly wound to form a tightly wound structure.The wire forming the heater element 1 is made of a chromium-aluminum-iron alloy. As such,
In addition, this wire has been subjected to oxidation treatment to form a coating mainly composed of aluminum oxide (HT2O3).This chromium-aluminum-iron alloy is said to have excellent resistance to aging in an oxidizing atmosphere. It has characteristics. In this alloy, chromium is a necessary component to provide oxidation resistance and sufficient corrosion resistance at high temperatures.If it is less than 10q6, abnormal oxidation easily occurs at high temperatures and oxidation resistance is insufficient, and if it exceeds 30q6 It is set in this range because it deteriorates workability and becomes hard and brittle when used at high temperatures for a long time. ``Aluminum, like chromium, is a necessary component to maintain oxidation and corrosion resistance at high temperatures, and at the same time, it is necessary to generate a good oxide film on the surface when heated to high temperatures. If the content is less than 1%, the above effect cannot be obtained, and if it exceeds 12%, the workability deteriorates, so this range is set. In order to facilitate machining, it is desirable that the aluminum be 8 or less. silicon,
Ma: / 7! The impurities contained in the deoxidizing material such as /7 and the alloy melt may be 2% or less by weight. For this reason,
The composition ratio of the alloy is 10 to 30% chromium and 1 to 30% aluminum.
12% balance iron, preferably chromium 15-25%, and 3-8% non-V aluminum balance iron. When a chromium-aluminum-iron alloy is oxidized, a film mainly composed of α-aluminum oxide is formed on the alloy surface. This coating exhibits excellent insulating properties even at high temperatures, and has strong adhesion and does not peel off easily.

Therefore, the heater element 1 made of a chromium-aluminum-iron alloy wire can securely and stably insulate each winding part of the υ coil by the aluminum oxide film, so that each winding part of the coil can be brought into close contact with each other. It can be formed by tightly wrapping it.

Since the infrared heater configured in this manner is formed by tightly winding the coil-shaped heater element l', it can be used as a vertical type by arranging the heater element l in the vertical direction as shown in the drawing. This allows the heater to radiate heat in the direction of a person's height, allowing for rational and efficient heating. In this case, since the heater element 1 is tightly wound, it is less likely to sag and deform due to its own weight.

Further, since the heater element 1 is formed by tightly wound, the element temperature can be increased. As a result, the heater element 1 heats the quartz tube 2 at a high temperature,
The quartz tube 2 can emit a lot of radiation.

Since the space between each winding portion of the heater element 1 can be reliably and stably ensured as described above, the heater element 1 can be kept tightly wound for a long period of time.
Can be used safely without causing short circuit accidents.

Furthermore, by closely winding the heater element 1t'', it is possible to use a wire rod with a larger diameter than that of the conventional heater element 1.

Therefore, the lifespan of the heater element 1 can be increased.

In the above-described embodiments, the case where the infrared heater is used vertically is described, but the infrared heater can also be used horizontally. In this case, a heater that emits a large amount of infrared rays can be obtained.

Here, the characteristics of the oxide film of the present invention will be described.

Table 1 describes the electrical resistance characteristics and peeling resistance of the produced oxide films for Examples and Comparative Examples of the present invention. At this time, the electrical resistance was measured using a voltmeter and a microammeter, and the peeling resistance was measured by peeling off the oxide film after sandblasting.

As is clear from Table 1, in Comparative Examples (1) and (2), a good oxide film could not be obtained and tight winding could not be achieved as an infrared heater. On the other hand, in Examples (1) to (4), a dense oxide film with good electrical resistance and adhesion was obtained;
Tight winding is now possible.

〔Effect of the invention〕

As explained above, the infrared heater of the present invention can be used as a vertical type, and can significantly improve heating characteristics and increase the amount of infrared radiation.

[Brief explanation of drawings]

The drawing is a longitudinal cross-sectional view showing an embodiment of the infrared rays and infrared rays of the present invention. 1... Heater element, 2... Quartz tube. Applicant's agent Patent attorney Takehiko Suzue Figure 1

Claims (6)

[Claims] (1) An infrared heater comprising a coiled heater element made of a chromium-aluminum-iron alloy having a surface oxide film and a quartz tube into which the heater element is inserted. (2) The infrared heater according to claim 1, wherein the chromium-aluminum-iron alloy has a component ratio of 10 to 30% chromium, 1 to 12% aluminum, and the remainder substantially iron. (3) Claim 2, characterized in that the chromium-aluminum-iron alloy contains 2% by weight or less of any one or more of titanium, zirconium, hafnium, yttrium, cerium, and lanthanum. infrared heater. (4) The infrared heater according to any one of claims 1 to 3, wherein the heater element is formed in a tightly wound manner. (5) The infrared heater according to any one of claims 1 to 4, wherein the heater elements are arranged vertically. (6) The infrared heater according to any one of claims 1 to 5, wherein the thickness of the surface oxide film is 10 to 70 μm.