JPS6322035B2 - - Google Patents
Info
- Publication number
- JPS6322035B2 JPS6322035B2 JP56076204A JP7620481A JPS6322035B2 JP S6322035 B2 JPS6322035 B2 JP S6322035B2 JP 56076204 A JP56076204 A JP 56076204A JP 7620481 A JP7620481 A JP 7620481A JP S6322035 B2 JPS6322035 B2 JP S6322035B2
- Authority
- JP
- Japan
- Prior art keywords
- powder
- oxide
- sheathed heater
- magnesia powder
- insulation resistance
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000000843 powder Substances 0.000 claims description 58
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 52
- 239000000395 magnesium oxide Substances 0.000 claims description 26
- 229910052751 metal Inorganic materials 0.000 claims description 14
- 239000002184 metal Substances 0.000 claims description 14
- 238000010438 heat treatment Methods 0.000 claims description 12
- 238000004519 manufacturing process Methods 0.000 claims description 8
- 229910000480 nickel oxide Inorganic materials 0.000 claims description 7
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 claims description 7
- 238000000034 method Methods 0.000 claims description 6
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 claims description 2
- 239000005751 Copper oxide Substances 0.000 claims description 2
- 229910000428 cobalt oxide Inorganic materials 0.000 claims description 2
- IVMYJDGYRUAWML-UHFFFAOYSA-N cobalt(ii) oxide Chemical compound [Co]=O IVMYJDGYRUAWML-UHFFFAOYSA-N 0.000 claims description 2
- 229910000431 copper oxide Inorganic materials 0.000 claims description 2
- AJNVQOSZGJRYEI-UHFFFAOYSA-N digallium;oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Ga+3].[Ga+3] AJNVQOSZGJRYEI-UHFFFAOYSA-N 0.000 claims description 2
- 229910001195 gallium oxide Inorganic materials 0.000 claims description 2
- QGLKJKCYBOYXKC-UHFFFAOYSA-N nonaoxidotritungsten Chemical compound O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 QGLKJKCYBOYXKC-UHFFFAOYSA-N 0.000 claims description 2
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 claims description 2
- 229910001887 tin oxide Inorganic materials 0.000 claims description 2
- 229910001930 tungsten oxide Inorganic materials 0.000 claims description 2
- 238000009413 insulation Methods 0.000 description 21
- 229910044991 metal oxide Inorganic materials 0.000 description 16
- 150000004706 metal oxides Chemical class 0.000 description 16
- 230000007423 decrease Effects 0.000 description 5
- 230000007774 longterm Effects 0.000 description 5
- 238000005204 segregation Methods 0.000 description 5
- 230000007547 defect Effects 0.000 description 3
- 230000002950 deficient Effects 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000010292 electrical insulation Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 229920006015 heat resistant resin Polymers 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 229910001293 incoloy Inorganic materials 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 239000011812 mixed powder Substances 0.000 description 1
- 229910001120 nichrome Inorganic materials 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Description
本発明はシーズヒータの製造方法に関し、特に
寿命が長く、かつ長時間使用後の使用状態におけ
る絶縁抵抗値の高いシーズヒータを安定して製造
する方法を提供しようとするものである。
一般に、シーズヒータは図面に示すように、両
端に端子棒１を備えたコイル状の電熱線２を金属
パイプ３に挿入し、この金属パイプ３に電融マグ
ネシア粉末等の電気絶縁粉末４を充填してなり、
必要に応じて金属パイプ３の両端をガラス５や耐
熱性樹脂６で封口してなるものである。
このシーズヒータは、加熱部品として、その非
常に優れた性能、品質、簡便さなどから飛躍的に
多用されてきており、家庭電化製品を初め、各種
工業用や宇宙開発、原子力などの特殊用途に至る
まで、その市場範囲は拡大してきている。その中
でも高温用シーズヒータの用途は今後さらに伸び
ていくものと思われる。
ところが、世界的視野でシーズヒータの性能お
よび品質の現状をみると、使用状態における絶縁
抵抗値（以下、熱時絶縁抵抗値と称す）が時間の
経過につれて低下してしまうという欠点と、電熱
線が断線するまでの時間が短かいという欠点があ
つた。
本発明者らは電気絶縁粉末４に着目し、各種検
討した結果、電気絶縁粉末４として金属酸化物粉
末を添加し、電熱線２の成分元素の蒸発現象を抑
えることにより、所期の目的である長時間使用後
の熱時絶縁抵抗値が高く、かつ寿命の長いシーズ
ヒータが得られるという結論を得ている。
一方、電気絶縁粉末４に添加する金属酸化物粉
末には均一な分散性を有すること、偏析の生じな
いこと、固有抵抗値の高いことなど多くの条件が
要求される。
しかし、市販の金属酸化物粉末を使用すると、
水散性の悪いものがあつたり、均一に分散しても
充填等の後工程において金属酸化物粉末の偏析が
生じたりするなどの欠点があつた。
このような現象はシーズヒータの特性、特に熱
時絶縁抵抗値の低下や耐電圧の低下の原因とな
り、シーズヒータの不良率を高め、好ましくな
い。
このような理由により、市販の金属酸化物粉末
を添加しただけでは、長時間使用後の熱時絶縁抵
抗値が高く、かつ寿命の長いシーズヒータを安定
して製造することは困難であつた。
本発明は上記金属酸化物粉末を添加した電気絶
縁粉末を用いるシーズヒータの製造方法において
生じる製造上の欠点を解消し、所期の目的を達成
するシーズヒータの製造方法を提供しようとする
ものである。
本発明の特徴は、マグネシア粉末に特定の金属
酸化物粉末を混合し、これを電融して金属酸化物
粉末がマグネシア粉末に固溶した電融マグネシア
粉末を生成し、この電融マグネシア粉末を900℃
〜1300℃の温度で熱処理したものを電気絶縁粉末
として用いることにある。
このように、金属酸化物粉末とマグネシア粉末
を同時に電融させると、金属酸化物粉末は、マグ
ネシア粉末中に固溶し、マグネシア粉末に金属酸
化物粉末を添加した時に生じる分散性や偏析の問
題は生じなくなるが、添加した金属酸化物粉末と
しての効果が、失なわれ、熱時絶縁抵抗値および
寿命の低下を抑えることができない。
しかし、電融させたのち、この電融マグネシア
粉末を900〜1300℃の温度で再熱処理すると、固
溶している金属酸化物が電融マグネシア粉末の表
面に金属酸化物として析出する。
この結果、本発明では、金属酸化物としての作
用が得られ、従来の方法で添加した場合と同様
に、長時間使用後の熱時絶縁抵抗値が高く、かつ
寿命の長いシーズヒータを得ることができる。
また、金属酸化物が電融マグネシア粉末の表面
に析出して存在するために分散や偏析の問題は生
じず安定してシーズヒータを製造することができ
る。
以下、本発明の実施例について説明する。
（実施例）
マグネシア粉末に、市販の酸化ニツケル粉末を
３重量％加えて、混合した。この混合粉末を電融
させ、電融マグネシア粉末を生成した。こののち
電融マグネシア粉末を420ミクロン以下に粉砕し、
第２表に示す温度で熱処理し、これを電気絶縁粉
末４として、それぞれ準備した。
なお、マグネシア粉末は第１表の組成比のもの
を用いた。
第１表
MgO 96〜97重量％
CaO 0.2〜0.3重量％
SiO2 ２〜３重量％
Al2O3 0.4〜0.5重量％
Fe2O3 0.14〜0.16重量％
また、電熱線２として線径0.29mmのニクロム線
第１種を用い、これを巻径２mmのコイル状とし、
両端に端子棒１を接続した。
さらに、金属パイプ３として長さ413mm、外径
８mm、肉厚0.46mmのNCF2P（商品名インコロイ
800）を用いた。
この金属パイプ３に上記端子棒１を両端に接続
した電熱線２を挿入し、この金属パイプ３にあら
かじめ準備しておいた上記電気絶縁粉末４を充填
し、圧延減径、焼鈍（1050℃、10分間）の各工程
を経て、金属パイプ３を長さ500mm、外径6.6mmと
し、さらに金属パイプ３の両端を低融点ガラス５
および耐熱性樹脂６で封口してシーズヒータを完
成した。
なお、比較のために、従来例として、電融マグ
ネシア粉末のみを電気絶縁粉末４として使用した
場合、さらに、比較例として市販の酸化ニツケル
粉末を１重量％添加した電融マグネシア粉末を無
処理で使用した場合についても同様にシーズヒー
タを完成した。
完成したそれぞれのシーズヒータの完成初期の
室温での絶縁抵抗値及びパイプ表面温度750℃で
の絶縁抵抗値室温での耐電圧を測定し、熱時絶縁
抵抗値が1MΩ以下、また耐電圧が1000V以下と
なるものを不良品として検出し、各グループにお
ける不良率を求めた。この結果を第２表に示す。
なお、第２表において、試料１は従来例を、試
料２は比較例を示す。
また、各試料について、以下に示すシーズヒー
タの寿命試験及び熱時絶縁抵抗値試験をそれぞれ
実施した。
〔寿命試験〕
各シーズヒータについて、金属パイプ３の表面
温度が950℃に維持されるように電熱線２に通電
し、電熱線２が断線するまでの日数を調べた。
〔熱時絶縁抵抗値試験〕
各シーズヒータについて、金属パイプ３の表面
温度が950℃に維持されるように電熱線２に通電
し、熱時絶縁抵抗値の変化を調べた。なお、熱時
絶縁抵抗値を測定する時は金属パイプ３の表面温
度を750℃に低下させて測定した。
上記寿命試験の結果ならびに熱時絶縁抵抗値試
験における11日後の熱時絶縁抵抗値の結果を第２
表に示す。
The present invention relates to a method for manufacturing a sheathed heater, and particularly provides a method for stably manufacturing a sheathed heater that has a long life and has a high insulation resistance value in a used state after long-term use. Generally, as shown in the drawing, a sheathed heater has a coiled heating wire 2 with terminal rods 1 at both ends inserted into a metal pipe 3, and this metal pipe 3 is filled with electrical insulating powder 4 such as fused magnesia powder. Then,
Both ends of the metal pipe 3 are sealed with glass 5 or heat-resistant resin 6 as required. This sheathed heater has been rapidly used as a heating component due to its excellent performance, quality, and simplicity, and is used in home appliances, various industries, space exploration, nuclear power, and other special applications. Since then, its market scope has been expanding. Among these, the use of high-temperature sheathed heaters is expected to continue to grow in the future. However, if we look at the current state of performance and quality of sheathed heaters from a global perspective, we find that their insulation resistance value (hereinafter referred to as hot insulation resistance value) decreases over time during use, and that the heating wire The disadvantage was that it took a short time for the wire to break. The present inventors focused on the electrical insulating powder 4, and as a result of various studies, by adding metal oxide powder as the electrical insulating powder 4 and suppressing the evaporation phenomenon of the component elements of the heating wire 2, it was possible to achieve the intended purpose. It has been concluded that a sheathed heater with a high insulation resistance value when hot after a certain long period of use and a long life can be obtained. On the other hand, the metal oxide powder added to the electrical insulating powder 4 is required to meet many conditions such as uniform dispersibility, no segregation, and high specific resistance. However, when using commercially available metal oxide powders,
There were drawbacks such as poor dispersibility in water, and segregation of the metal oxide powder during post-processes such as filling even if it was uniformly dispersed. Such a phenomenon causes a decrease in the properties of the sheathed heater, particularly a decrease in the insulation resistance value during heating and a decrease in the withstand voltage, which increases the defective rate of the sheathed heater, which is undesirable. For these reasons, it has been difficult to stably produce a sheathed heater that has a high insulation resistance value when heated and has a long life after long-term use just by adding commercially available metal oxide powder. The present invention aims to provide a method for manufacturing a sheathed heater that eliminates the manufacturing defects that occur in the manufacturing method of a sheathed heater using electrically insulating powder to which the metal oxide powder is added, and achieves the intended purpose. be. The feature of the present invention is to mix a specific metal oxide powder with magnesia powder and electrolyze it to produce an electrofused magnesia powder in which the metal oxide powder is solidly dissolved in the magnesia powder. 900℃
The purpose is to use the product heat-treated at a temperature of ~1300°C as an electrical insulating powder. In this way, when metal oxide powder and magnesia powder are electrically melted at the same time, the metal oxide powder becomes a solid solution in the magnesia powder, and problems with dispersibility and segregation that occur when metal oxide powder is added to magnesia powder can be solved. However, the effect of the added metal oxide powder is lost, and the decrease in insulation resistance value and life when heated cannot be suppressed. However, when this electrofused magnesia powder is reheated at a temperature of 900 to 1300° C. after being electrically melted, the solid solution metal oxide is precipitated on the surface of the electrofused magnesia powder as a metal oxide. As a result, in the present invention, it is possible to obtain a sheathed heater that functions as a metal oxide, has a high insulation resistance value when heated after long-term use, and has a long life, similar to when it is added by the conventional method. Can be done. In addition, since the metal oxide is precipitated and present on the surface of the electrofused magnesia powder, problems of dispersion and segregation do not occur, and the sheathed heater can be stably manufactured. Examples of the present invention will be described below. (Example) 3% by weight of commercially available nickel oxide powder was added to magnesia powder and mixed. This mixed powder was electrofused to produce electrofused magnesia powder. After this, the electrofused magnesia powder is crushed to 420 microns or less,
The powders were heat treated at the temperatures shown in Table 2 and prepared as electrical insulating powder 4. The magnesia powder used had the composition ratio shown in Table 1. Table 1 MgO 96-97% by weight CaO 0.2-0.3% by weight SiO 2 2-3% by weight Al 2 O 3 0.4-0.5% by weight Fe 2 O 3 0.14-0.16% by weight In addition, the heating wire 2 has a wire diameter of 0.29 mm. Using type 1 nichrome wire, it was made into a coil with a winding diameter of 2 mm.
Terminal bar 1 was connected to both ends. Furthermore, as the metal pipe 3, NCF2P (product name Incoloy) with length 413 mm, outer diameter 8 mm, wall thickness 0.46 mm
800) was used. The heating wire 2 with the terminal rod 1 connected to both ends is inserted into the metal pipe 3, the metal pipe 3 is filled with the electrical insulation powder 4 prepared in advance, and the metal pipe 3 is reduced in diameter and annealed (1050°C, After each step (10 minutes), the metal pipe 3 was made to have a length of 500 mm and an outer diameter of 6.6 mm, and both ends of the metal pipe 3 were coated with low melting glass 5.
Then, the sheathed heater was completed by sealing with heat-resistant resin 6. For comparison, as a conventional example, only fused magnesia powder was used as electrical insulating powder 4, and as a comparative example, fused magnesia powder to which 1% by weight of commercially available nickel oxide powder was added was used without any treatment. A sheathed heater was also completed in the same way. The insulation resistance value at room temperature at the initial stage of completion of each completed sheathed heater, the insulation resistance value at pipe surface temperature of 750℃, and the withstand voltage at room temperature were measured, and the insulation resistance value when heated was 1MΩ or less, and the withstand voltage was 1000V. The following items were detected as defective products, and the defect rate in each group was determined. The results are shown in Table 2. In Table 2, Sample 1 shows a conventional example, and Sample 2 shows a comparative example. In addition, for each sample, a sheathed heater life test and a heat insulation resistance test described below were conducted. [Lifetime test] For each sheathed heater, the heating wire 2 was energized so that the surface temperature of the metal pipe 3 was maintained at 950° C., and the number of days until the heating wire 2 broke was examined. [Insulation resistance value test when heated] For each sheathed heater, the heating wire 2 was energized so that the surface temperature of the metal pipe 3 was maintained at 950° C., and changes in the insulation resistance value when heated were examined. In addition, when measuring the insulation resistance value under heat, the surface temperature of the metal pipe 3 was lowered to 750°C. The results of the above life test and the thermal insulation resistance value after 11 days in the thermal insulation resistance value test are
Shown in the table.
【表】
第２表から明らかなように、市販の酸化ニツケ
ル粉末を添加したのち無処理の電気絶縁粉末を使
用した試料２では、不良率が、電融マグネシア粉
末のみを使用した試料１と比較して、著しく高く
なつているが、電融させた試料３〜９において
は、分散及び偏析の原因による不良率が著しく抑
えられ、試料１と同レベルの低い値を示した。
さらに、本発明の範囲内にある試料６〜９で
は、従来の電融マグネシア粉末のみを使用した試
料１と比較して、寿命は約10倍となり、また11日
後の熱時絶縁抵抗値においても、高い値を示し
た。
一方、本発明の範囲外にある試料３〜５では、
熱時絶縁抵抗値および寿命において、著しい効果
は見られなかつた。
このように、マグネシア粉末に酸化ニツケル粉
末を混合したものを電融させ、この電融マグネシ
ア粉末を900℃〜1300℃の温度で熱処理し、電融
マグネシア粉末の表面上に酸化ニツケルを析出さ
せた電気絶縁粉末を用いてシーズヒータを構成す
ると、長時間使用後の熱時絶縁抵抗値が高く、か
つ寿命の長いシーズヒータを安定して得られる。
なお、上記実施例において、酸化ニツケル粉末
を用いたが、酸化コバルト、酸化タングステン、
酸化銅、酸化ガリウム、酸化錫の各粉末を用いて
も同様の傾向を示した。
以上の説明から明らかなように、本発明の製造
方法によれば、長時間使用後における熱時絶縁抵
抗値が高く、かつ寿命の長いシーズヒータを安定
して提供することができる。[Table] As is clear from Table 2, sample 2, which used untreated electrical insulating powder after adding commercially available nickel oxide powder, had a lower defect rate compared to sample 1, which used only fused magnesia powder. However, in samples 3 to 9 which were electrically melted, the defective rate due to dispersion and segregation was significantly suppressed, and showed a low value on the same level as sample 1. Furthermore, in Samples 6 to 9, which fall within the scope of the present invention, the lifespan is approximately 10 times that of Sample 1, which uses only conventional electrofused magnesia powder, and the thermal insulation resistance value after 11 days also increases. , showed a high value. On the other hand, in samples 3 to 5 which are outside the scope of the present invention,
No significant effect was observed on insulation resistance value or lifespan when heated. In this way, a mixture of magnesia powder and nickel oxide powder was electrofused, and the fused magnesia powder was heat-treated at a temperature of 900°C to 1300°C to precipitate nickel oxide on the surface of the fused magnesia powder. When a sheathed heater is constructed using electrically insulating powder, it is possible to stably obtain a sheathed heater that has a high insulation resistance value when hot after long-term use, and has a long life. In the above examples, nickel oxide powder was used, but cobalt oxide, tungsten oxide,
Similar trends were observed when copper oxide, gallium oxide, and tin oxide powders were used. As is clear from the above description, according to the manufacturing method of the present invention, it is possible to stably provide a sheathed heater that has a high insulation resistance value when hot after long-term use and has a long life.
図は一般的なシーズヒータの断面図である。
２……電熱線、３……金属パイプ、４……電気
絶縁粉末。
The figure is a cross-sectional view of a typical sheathed heater. 2... Heating wire, 3... Metal pipe, 4... Electrical insulation powder.
Claims (1)
気絶縁粉末を充填してなるシーズヒータの製造方
法において、酸化ニツケル、酸化コバルト、酸化
タングステン、酸化銅、酸化ガリウム、酸化錫の
群から選ばれる少くとも一種の酸化物をマグネシ
ア粉末に混合し、これを電融して前記酸化物が前
記マグネシア粉末に固溶した電融マグネシア粉末
を生成し、この電融マグネシア粉末を900℃〜
1300℃の温度で熱処理したものを前記電気絶縁粉
末として用いることを特徴とするシーズヒータの
製造方法。1. A method for manufacturing a sheathed heater in which a heating wire is inserted into a metal pipe and the electrically insulating powder is filled with at least one selected from the group of nickel oxide, cobalt oxide, tungsten oxide, copper oxide, gallium oxide, and tin oxide. A type of oxide is mixed with magnesia powder, and this is electrofused to produce an fused magnesia powder in which the oxide is solidly dissolved in the magnesia powder, and this fused magnesia powder is heated at 900°C to
A method for manufacturing a sheathed heater, characterized in that the electrical insulating powder is heat-treated at a temperature of 1300°C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56076204A JPS57191976A (en) | 1981-05-19 | 1981-05-19 | Method of producing sheathed heater |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56076204A JPS57191976A (en) | 1981-05-19 | 1981-05-19 | Method of producing sheathed heater |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57191976A JPS57191976A (en) | 1982-11-25 |
| JPS6322035B2 true JPS6322035B2 (en) | 1988-05-10 |
Family
ID=13598622
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56076204A Granted JPS57191976A (en) | 1981-05-19 | 1981-05-19 | Method of producing sheathed heater |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57191976A (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5749189A (en) * | 1980-09-08 | 1982-03-20 | Matsushita Electric Ind Co Ltd | Sheathed heater and method of producing same |
-
1981
- 1981-05-19 JP JP56076204A patent/JPS57191976A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5749189A (en) * | 1980-09-08 | 1982-03-20 | Matsushita Electric Ind Co Ltd | Sheathed heater and method of producing same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57191976A (en) | 1982-11-25 |
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