JP3813234B2

JP3813234B2 - Porous electric resistance heater

Info

Publication number: JP3813234B2
Application number: JP08328896A
Authority: JP
Inventors: 三千郎小堤; 敏彦武本; 紀夫広保; 伸介小原
Original assignee: Nisshin Steel Co Ltd
Current assignee: Nippon Steel Nisshin Co Ltd
Priority date: 1996-03-11
Filing date: 1996-03-11
Publication date: 2006-08-23
Anticipated expiration: 2016-03-11
Also published as: JPH09245938A

Description

【０００１】
【産業上の利用分野】
本発明は、全抵抗が高く構造体強度に優れ、内部を通過する気体や液体に効率よく熱伝達する多孔体製の電気抵抗ヒータに関する。
【０００２】
【従来の技術及び問題点】
自動車排ガス浄化用の触媒系では、触媒を早期着火させる効率的加熱のため、比較的大型のヒータを使用する場合がある。そのため、より高い比抵抗をもつと共に、耐熱性，耐食性等に優れた材料開発が進められている。たとえば、特開平７−３１０３８号公報では、Ａｌを８〜２０重量％含むＦｅ−Ｃｒ系のヒータ用合金が紹介されている。しかし、大型のブロック状ヒータを金属材料で構成すると、ヒータの電気抵抗が小さくなり、所望の電力を得るためには大きな電流を供給することが必要となり、実用的でなくなる。
また、電気抵抗を大きくするため、ハニカム構造体にスリットを形成することも知られている。しかし、スリットの形成によりハニカム構造体の強度が低下するため、効率的加熱に適した大型ヒータを得るに至っていないのが実情である。
【０００３】
【課題を解決するための手段】
本発明は、このような問題を解消すべく案出されたものであり、先に特願平６−１８１８１８号で提案した多孔体ブロックが基体又は液体に対する接触面積が大きく且つ熱伝達特性にも優れている点に着目し、この多孔体ブロックをヒータとして使用することにより、大型で全抵抗が高く構造体強度及び加熱効率に優れた電気抵抗ヒータを提供することを目的とする。
本発明の多孔体製電気抵抗ヒータは、その目的を達成するため、波形又は凹凸状にプレス成形され、表面が絶縁処理された金属板又は箔材を隣接する面が相互に絶縁されるようにツヅラ折り状に積層した構造をもち、周縁にヨーク状突起又はバリをもつ貫通孔が前記波形又は凹凸状の山部又は谷部に穿設されている。金属板又は箔材は、隣接する面が相互に絶縁されるように渦巻き状に巻き込むこともできる。ツヅラ折りの方向又は渦巻き状の巻込み方向に対し、波形又は凹凸の波面方向を傾斜させることが好ましい。
金属板又は箔材の材質には、たとえばＣｒ：８〜３０重量％，Ａｌ：８重量％以下，Ｔｉ：１重量％以下及びＭｏ：３重量％以下を含むＦｅ合金がある。
【０００４】
【実施の形態】
本発明で使用される金属板又は箔材１０は、表面が絶縁処理され、図１に示すように規則的且つ周期的に波形又は凹凸１１が形成されている。
波形又は凹凸１１は、波面方向に断面形状を周期的に変化させるウネリをつけることが好ましい。波形又は凹凸１１の山部，谷部又は中腹に、ヨーク状突起又はバリ１２のある貫通孔１３が形成されている。
波形又は凹凸１１がつけられた金属板又は箔材１０は、図２に示すように積層され、或いは図３に示すように渦巻状に巻き込まれる。これにより、液体や気体が通過する隙間１４が、金属板又は箔材１０の隣接間に形成される。図２の積層体では、左右方向，奥行方法，上下方向の何れかの方向に沿って液体又は気体を流すことができる。図３の巻込み構造では、上下方向に沿って液体又は気体が流される。
【０００５】
隣接した金属板又は箔材１０のヨーク状突起又はバリ１２は、図４に示すようにところどころで噛み合い、積層又は巻き込んだ多孔体としての形状安定性を確保する。ヨーク状突起又はバリ１２は、このように液体又は気体通過用の隙間１４を確保すると共に、通過する液体又は気体との熱交換を促進させる。
多孔体は、金属板又は箔材１０をツヅラ折り状に折り畳むことにより形成される。この場合、機械的に弱くなったり一部が破断して電気抵抗が局部的に高くなりがちな折曲げ部は、スポット溶接等によって補強することが好ましい。また、裁断した金属板又は箔材１０を重ね合わせ、交互に反対側を溶接することによってツヅラ折り状の多孔体とすることもできる。この場合、形成された多孔体は、直方体状のブロックとなる。また、渦巻き状にする場合、図５に示すように、波形又は凹凸１１及び貫通孔１３が設けられた金属板又は箔材１０を先ず二つ折りにし、次いで渦巻き状に巻き込むことが好ましい。
【０００６】
金属板又は箔材１０につける波形又は凹凸１１は、ツヅラ折りの方向又は巻き込み方向に対して波面方向が傾斜していることが好ましい。傾斜した波面に沿って位置する波形又は凹凸１１は、たとえば図６に示すように金属板又は箔材１０をツヅラ折り状に折り畳むと、Ａ面及びＢ面では傾斜方向が図７に示すように逆方向になる。そのため、折り畳まれた金属板又は箔材１０のＡ面とＢ面とが密着することなく、両面間の空隙分布が一様になる。二つ折りした金属板又は箔材１０を渦巻き状に巻き込む場合（図５）にも、同様に隣接面間で波形又は凹凸１１の傾斜方向が逆方向になるため、両面間の空隙分布が一様になる。
金属板又は箔材１０は、隣接する面が相互に絶縁されるように、多孔体としてブロック状に固定される前に表面に絶縁膜を形成することが必要である。絶縁膜は、酸化雰囲気中で金属板又は箔材１０を加熱する方法，セラミックス等の絶縁物をコーティングする方法等によって形成される。また、場合によっては、絶縁性のスペーサを介在させても良い。このように隣接面間が絶縁された金属板又は箔材１０の長手方向両端に電極を取り付けると、全体として長尺の抵抗加熱ヒータとなり、電気抵抗発熱体として必要な全抵抗が確保できると共に、隙間１４を通過する液体又は気体との熱交換が促進される。また、波形又は凹凸形状が互いに傾斜をもってツヅラ折り状に積層又は渦巻状に巻き込まれることにより、全体としてハニカム構造になり、優れた構造体強度をもつものとなる。
【０００７】
金属板又は箔材１０としては、耐熱性，耐酸化性，緻密性に優れた不動態皮膜を形成するＣｒ：８〜３０重量％，Ｓｉ：５重量％以下，Ａｌ：８重量％以下，Ｔｉ：１重量％以下及びＭｏ：３重量％以下を含むステンレス鋼が使用される。Ｃｒは、耐熱性及び耐酸化性に必要な合金元素であり、８重量％以上の含有量でＣｒ添加の作用が顕著になる。しかし、３０重量％を超える多量のＣｒが含まれると、脆化による製造性や加工性が劣化するため好ましくない。
Ｓｉは、耐熱性及び耐酸化性の向上に有効であるが、５重量％を超える多量のＳｉが含まれると鋼を硬化させ、加工性を劣化させる。Ａｌは、耐熱性，耐酸化性及び不動態皮膜の緻密性を向上させる上で有効な合金元素であるが、５重量％を超える多量のＡｌが含まれると、製造性が劣化する。Ｔｉは、耐熱性，耐酸化性及び不動態皮膜の緻密性を向上させる上で有効な合金元素であるが、１重量％を超える多量のＴｉが含まれると、製造性が劣化する。Ｍｏは、耐熱性及び耐酸化性の向上に有効であるが、３重量％を超える多量のＭｏが含まれると加工性が劣化する。
【０００８】
【作用】
ステンレス鋼は、鋼材の中では高抵抗であるものの、ニクロムに比較すると電気抵抗が低いことから、ヒータ材料として使用しづらい。しかし、本発明に従ったヒータでは、金属板又は箔材１０を波形又は凹凸状に加工していることから長さ方向に対する見掛けの比抵抗が大きくなり、更にツヅラ折り状に積層又は渦巻状に巻き込むことによって、一層電流の流れる距離を長く取ることができる。そのため、ヒータ全体としての抵抗値が高くなり、焼結等で作成した多孔体のように切込み等の加工が不要で、積層又は巻込みによりハニカム構造体となることから、構造体としての強度を得ることができる。その結果、設計上、素材選択の自由度が高くなる。
【０００９】
積層（図２）又は渦巻状（図３，図５）に巻き込んだ多孔体ブロックの両端に電極を接続して電流を流すとき、多孔体は全体に均一加熱される。この条件下で多孔体の内部に液体又は気体を流すと、加熱された多孔体と液体又は気体との間で効率よく熱交換が行われる。その結果、液体又は気体が短時間に加熱される。この多孔体では隙間１４を均一に形成できるため、発熱量も均一になる。しかし、場合によっては一部の材質や波形パターンを変更することにより、たとえば周辺部と中心部とで発熱量を意図的に変えることもできる。
この多孔体ブロックは、電気温風機，ヘアドライヤ等に電気ヒータとして組み込むこともできる。この場合、従来のようにヒータを赤熱する必要がないので安全な電気機器となり、素材としてニクロムのように高価な材料を使用する必要がないことからヒータ自体も安価になる。また、排ガス処理のアフターバーナのような用途に使用することもでき、適度に加熱した多孔体の内部に排ガスを通過させることによって希薄な未燃焼排ガスが完全に燃焼し、クリーンな排ガスとなる。
【００１０】
【実施例】
実施例１：
Ｃｒ：１１重量％，Ｓｉ：０．６重量％，Ａｌ：０．０５重量％，Ｔｉ：０．３重量％を含む厚み１００μｍ，幅４０ｍｍ，長さ２０００ｍｍのステンレス鋼板を、波形ピッチ１．８ｍｍ，振幅（波の深さ）０．６ｍｍの波形形状（図１）にプレス成形した。波形１１の頂部に、高さ０．２ｍｍのバリ１２を周縁にもつ貫通孔１３を形成した。次いで、バリ１２の尖鋭部が酸化皮膜を疵付けないように、ステンレス鋼板にビーズブラストをかけた。
処理後のステンレス鋼板を２０ｍｍ長さで切断し、短冊状の板３２枚を重ね合わせた。各板の両端を交互にスポット溶接し、ツヅラ折り状にした。ツヅラ折り状を軽くたたんで、ブロックとした。このブロックを湿潤水素雰囲気中で１０００℃×４５分間の加熱酸化処理を施し、良好な絶縁皮膜をステンレス鋼表面に形成した。
【００１１】
ツヅラ折り状のステンレス鋼板の長手方向両端部の酸化皮膜を一部除去し、ニッケル板をスポット溶接して電極を取り付けた。このようにして、幅４０ｍｍ，厚み４０ｍｍ，長さ２０ｍｍの直方体状多孔体ヒータを得た。この多孔体ヒータの電気抵抗は、約３Ωであった。多孔体ヒータを石英管内に固定し、電極に１０Ｖの電圧を印加すると約３Ａの電流が流れ、４０秒で約１００℃まで昇温した。
【００１２】
実施例２：
Ｃｒ：１８重量％，Ｓｉ：０．４重量％，Ａｌ：３．２重量％，Ｔｉ：０．１４重量％を含む厚み５０μｍ，幅４０ｍｍのステンレス鋼箔に、プレス成形によって波形ピッチ１．８ｍｍ，振幅（波の深さ）０．６ｍｍの波形形状（図１）をつけた。この例では、波型の波面方向を５度傾斜させた。波形１１の頂部に、高さ０．２ｍｍのバリ１２を周縁にもつ貫通孔１３を形成した。次いで、バリ１２の尖鋭部が酸化皮膜を疵付けないように、ステンレス鋼板にビーズブラストをかけた。
次いで、ステンレス鋼箔を二つ折りし、二重螺旋状（図５）に巻き込み、きつく巻いた状態での直径が６０ｍｍの円筒状多孔体とした。この円筒状多孔体の巻き込み状態を若干緩め、湿潤水素雰囲気中で１０００℃×４５分間の加熱酸化処理を施した。酸化処理後、円筒状多孔体をきつく巻き締めても、長手方向両端間の電気抵抗は常温で約８Ωと一定の値を示し、良好な絶縁皮膜が形成されていることが確認された。
【００１３】
ステンレス鋼箔の長手方向両端に、ニッケル箔をスポット溶接して電極を取り付けた。得られた円筒状多孔体を、外径６５ｍｍの固定用石英管に挿入した。この状態における円筒状多孔体の開口率は、重量法で実測したところ９３％であった。
円筒状多孔体の電極に１０Ｖの電圧を印加し約１Ａの電流を流すと、１分間で１００℃程度に昇温した。また、１００Ｖの電圧で約１０Ａの電流を流すと、１５秒程度で赤熱した。この円筒状多孔体も、実施例１の多孔体ヒータと同様に優れた熱交換性能を呈した。
【００１４】
【発明の効果】
以上に説明したように、本発明の電気抵抗ヒータは、表面が絶縁処理された金属板又は箔材を積層又は渦巻き状に巻き込んだ多孔体を使用している。この多孔体は、熱伝達効率が良く、内部を通過する液体又は気体を短時間に加熱する、また、希薄なガスや未燃焼成分を含むガスであっても容易に燃焼させることから、排気ガスのアフターバーナ等としても使用される。しかも、従来の焼結体に比較して簡単に製造できることから、各種ヒータとして広範な分野で使用される。
【図面の簡単な説明】
【図１】プレス成形した金属板又は箔材
【図２】積層した金属板又は箔材
【図３】渦巻き状に巻き込んだ金属板又は箔材
【図４】隣接するバリが絡み合った金属板又は箔材
【図５】二重螺旋状に巻き込んだ金属板又は箔材
【図６】ツヅラ折り状の金属板又は箔材
【図７】ツヅラ折りされた隣接面（Ａ）と（Ｂ）とで波面方向が逆になっている波形又は凹凸
【符号の説明】
１０：金属板又は箔材１１：波形又は凹凸１２：ヨーク状突起又はバリ１３：貫通孔１４：隙間[0001]
[Industrial application fields]
The present invention relates to an electrical resistance heater made of a porous material that has high total resistance and excellent structure strength, and that efficiently transfers heat to a gas or liquid passing through the inside.
[0002]
[Prior art and problems]
In a catalyst system for purifying automobile exhaust gas, a relatively large heater may be used for efficient heating for early ignition of the catalyst. For this reason, development of materials having higher specific resistance and excellent heat resistance, corrosion resistance and the like is underway. For example, Japanese Patent Laid-Open No. 7-31038 introduces an Fe—Cr heater alloy containing 8 to 20% by weight of Al. However, when a large block heater is made of a metal material, the electric resistance of the heater is reduced, and it is necessary to supply a large current in order to obtain a desired power, which is not practical.
It is also known to form slits in the honeycomb structure in order to increase electric resistance. However, since the strength of the honeycomb structure decreases due to the formation of the slits, the actual situation is that a large heater suitable for efficient heating has not been obtained.
[0003]
[Means for Solving the Problems]
The present invention has been devised to solve such problems, and the porous body block previously proposed in Japanese Patent Application No. 6-181818 has a large contact area with respect to the substrate or liquid and also has heat transfer characteristics. By paying attention to the excellent point and using this porous body block as a heater, an object is to provide a large-sized electric resistance heater having high total resistance and excellent structure strength and heating efficiency.
In order to achieve the object, the porous electrical resistance heater according to the present invention is formed in a corrugated or concavo-convex shape so that adjacent surfaces of a metal plate or foil material whose surfaces are insulated are insulated from each other. A through-hole having a structure that is laminated in a fold-like shape and having a yoke-like protrusion or burr on the periphery is formed in the corrugated or uneven peak or valley. The metal plate or foil material can also be wound in a spiral shape so that adjacent surfaces are insulated from each other . It is preferable to incline the wavefront direction of the corrugations or irregularities with respect to the direction of the fold or the spiral winding direction.
Examples of the material of the metal plate or foil material include an Fe alloy containing Cr: 8 to 30% by weight, Al: 8% by weight or less, Ti: 1% by weight or less, and Mo: 3% by weight or less.
[0004]
Embodiment
The surface of the metal plate or foil material 10 used in the present invention is insulated, and the corrugations or irregularities 11 are regularly and periodically formed as shown in FIG.
It is preferable that the corrugations or irregularities 11 have undulations that periodically change the cross-sectional shape in the wavefront direction. A through-hole 13 having a yoke-like protrusion or burr 12 is formed in a peak portion, valley portion, or middle of the corrugated or uneven portion 11.
The metal plate or foil material 10 provided with the corrugations or irregularities 11 is laminated as shown in FIG. 2 or is wound in a spiral shape as shown in FIG. Thereby, a gap 14 through which liquid or gas passes is formed between adjacent metal plates or foil members 10. In the laminated body of FIG. 2, a liquid or gas can be flowed along any direction of the left-right direction, the depth method, and the up-down direction. In the entrainment structure of FIG. 3, a liquid or gas flows along the vertical direction.
[0005]
As shown in FIG. 4, the yoke-like protrusions or burrs 12 of the adjacent metal plate or foil material 10 are engaged with each other to ensure shape stability as a laminated or rolled porous body. The yoke-like protrusions or burrs 12 thus secure the gap 14 for passing the liquid or gas and promote heat exchange with the passing liquid or gas.
The porous body is formed by folding the metal plate or the foil material 10 into a spiral fold shape. In this case, it is preferable to reinforce the bent portion, which tends to be mechanically weak or partially broken and whose electric resistance tends to increase locally, by spot welding or the like. Moreover, the metal plate or foil material 10 cut | judged can be overlap | superposed, and it can also be set as a spiral fold-shaped porous body by welding the other side alternately. In this case, the formed porous body is a rectangular parallelepiped block. Moreover, when making it into a spiral shape, as shown in FIG. 5, it is preferable to first fold the metal plate or foil material 10 provided with the corrugations or irregularities 11 and the through-holes 13 into a spiral shape, and then wind it in a spiral shape.
[0006]
It is preferable that the wavefront direction of the corrugation or unevenness 11 attached to the metal plate or the foil material 10 is inclined with respect to the direction of the fold or the winding direction. As shown in FIG. 6, for example, when the metal plate or the foil material 10 is folded in a spiral fold shape, the corrugation or unevenness 11 positioned along the inclined wavefront has the inclination direction as shown in FIG. Reverse direction. Therefore, the space | gap distribution between both surfaces becomes uniform, without the A surface and B surface of the folded metal plate or foil material 10 contact | adhering. Similarly, when the folded metal plate or foil material 10 is spirally wound (FIG. 5), the corrugation or unevenness 11 is inclined in the opposite direction between the adjacent surfaces, so that the air gap distribution between both surfaces is uniform. become.
It is necessary to form an insulating film on the surface of the metal plate or foil material 10 before being fixed in a block shape as a porous body so that adjacent surfaces are insulated from each other. The insulating film is formed by a method of heating the metal plate or foil material 10 in an oxidizing atmosphere, a method of coating an insulating material such as ceramics, or the like. In some cases, an insulating spacer may be interposed. When the electrodes are attached to both ends in the longitudinal direction of the metal plate or foil material 10 in which the adjacent surfaces are insulated in this way, a long resistance heater is formed as a whole, and the entire resistance necessary as an electric resistance heating element can be secured, Heat exchange with the liquid or gas passing through the gap 14 is promoted. Further, when the corrugations or the uneven shapes are stacked in a spiral fold shape or wound in a spiral shape with an inclination, a honeycomb structure is obtained as a whole, and an excellent structure strength is obtained.
[0007]
As the metal plate or foil material 10, Cr: 8 to 30% by weight, Si: 5% by weight or less, Al: 8% by weight or less, Ti forming a passive film excellent in heat resistance, oxidation resistance and denseness, Ti Stainless steel containing 1% by weight or less and Mo: 3% by weight or less is used. Cr is an alloy element necessary for heat resistance and oxidation resistance, and the effect of addition of Cr becomes remarkable when the content is 8% by weight or more. However, if a large amount of Cr exceeding 30% by weight is contained, manufacturability and workability due to embrittlement deteriorate, which is not preferable.
Si is effective in improving heat resistance and oxidation resistance, but if a large amount of Si exceeding 5% by weight is contained, the steel is hardened and the workability is deteriorated. Al is an alloy element that is effective in improving heat resistance, oxidation resistance and the denseness of the passive film. However, if a large amount of Al exceeding 5% by weight is contained, productivity is deteriorated. Ti is an alloy element that is effective in improving heat resistance, oxidation resistance and denseness of the passive film. However, if a large amount of Ti exceeding 1% by weight is contained, productivity deteriorates. Mo is effective in improving heat resistance and oxidation resistance, but if a large amount of Mo exceeding 3% by weight is contained, workability deteriorates.
[0008]
[Action]
Although stainless steel has a high resistance among steel materials, it is difficult to use as a heater material because it has a lower electrical resistance than nichrome. However, in the heater according to the present invention, since the metal plate or the foil material 10 is processed into a corrugated or uneven shape, the apparent specific resistance with respect to the length direction is increased, and further, laminated or spirally in a spiral fold shape. By entraining, it is possible to further increase the current flowing distance. Therefore, the resistance value as a whole of the heater is increased, and processing such as cutting is not required like a porous body made by sintering or the like, and a honeycomb structure is formed by stacking or winding. Obtainable. As a result, the degree of freedom in material selection is high in design.
[0009]
When an electrode is connected to both ends of a porous body block wound in a stack (FIG. 2) or a spiral shape (FIGS. 3 and 5) and an electric current is passed, the porous body is uniformly heated as a whole. When a liquid or gas is allowed to flow inside the porous body under these conditions, heat exchange is efficiently performed between the heated porous body and the liquid or gas. As a result, the liquid or gas is heated in a short time. In this porous body, since the gaps 14 can be formed uniformly, the amount of heat generated is also uniform. However, in some cases, the amount of heat generated can be changed intentionally, for example, between the peripheral portion and the central portion by changing a part of the material and the waveform pattern.
The porous body block can be incorporated as an electric heater in an electric warm air machine, a hair dryer or the like. In this case, since it is not necessary to heat the heater red as in the prior art, it becomes a safe electric device, and since it is not necessary to use an expensive material such as nichrome as a material, the heater itself is also inexpensive. Moreover, it can also be used for applications such as an afterburner for exhaust gas treatment. By passing the exhaust gas through a suitably heated porous body, the lean unburned exhaust gas is completely burned and becomes clean exhaust gas.
[0010]
【Example】
Example 1:
A stainless steel plate having a thickness of 100 μm, a width of 40 mm and a length of 2000 mm including Cr: 11% by weight, Si: 0.6% by weight, Al: 0.05% by weight, Ti: 0.3% by weight, and a corrugated pitch of 1.8 mm. , And press-molded into a waveform shape (FIG. 1) having an amplitude (wave depth) of 0.6 mm. A through-hole 13 having a burr 12 having a height of 0.2 mm at the periphery was formed at the top of the waveform 11. Next, bead blasting was applied to the stainless steel plate so that the sharp part of the burr 12 did not scratch the oxide film.
The treated stainless steel plate was cut to a length of 20 mm, and 32 strip-shaped plates were superposed. The both ends of each plate were spot welded alternately to form a spiral fold. The folds of the crane were folded lightly to make a block. This block was heat-oxidized at 1000 ° C. for 45 minutes in a wet hydrogen atmosphere to form a good insulating film on the stainless steel surface.
[0011]
A part of the oxide film at both ends in the longitudinal direction of the stainless steel plate in a fold-like shape was removed, and a nickel plate was spot welded to attach an electrode. Thus, a rectangular parallelepiped porous heater having a width of 40 mm, a thickness of 40 mm, and a length of 20 mm was obtained. The electrical resistance of this porous heater was about 3Ω. When a porous heater was fixed in the quartz tube and a voltage of 10 V was applied to the electrode, a current of about 3 A flowed and the temperature was raised to about 100 ° C. in 40 seconds.
[0012]
Example 2:
Corrugated pitch of 1.8 mm by press forming on stainless steel foil with thickness of 50 μm and width of 40 mm including Cr: 18 wt%, Si: 0.4 wt%, Al: 3.2 wt%, Ti: 0.14 wt% A waveform shape (FIG. 1) having an amplitude (wave depth) of 0.6 mm was applied. In this example, the wavefront direction of the wave is inclined by 5 degrees. A through-hole 13 having a burr 12 having a height of 0.2 mm at the periphery was formed at the top of the waveform 11. Next, bead blasting was applied to the stainless steel plate so that the sharp part of the burr 12 did not scratch the oxide film.
Next, the stainless steel foil was folded in half and wound into a double spiral shape (FIG. 5) to form a cylindrical porous body having a diameter of 60 mm in a tightly wound state. The cylindrical porous body was slightly loosened and subjected to a heat oxidation treatment at 1000 ° C. for 45 minutes in a wet hydrogen atmosphere. Even after the oxidation treatment, even when the cylindrical porous body was tightly wound, the electrical resistance between both ends in the longitudinal direction showed a constant value of about 8Ω at room temperature, and it was confirmed that a good insulating film was formed.
[0013]
Electrodes were attached to both ends of the stainless steel foil in the longitudinal direction by spot welding of nickel foil. The obtained cylindrical porous body was inserted into a fixing quartz tube having an outer diameter of 65 mm. The opening ratio of the cylindrical porous body in this state was 93% when measured by a weight method.
When a voltage of 10 V was applied to the cylindrical porous body electrode and a current of about 1 A was applied, the temperature was raised to about 100 ° C. in 1 minute. In addition, when a current of about 10 A was applied at a voltage of 100 V, it heated red in about 15 seconds. This cylindrical porous body also exhibited excellent heat exchange performance, similar to the porous heater of Example 1.
[0014]
【The invention's effect】
As described above, the electric resistance heater of the present invention uses a porous body in which a metal plate or a foil material whose surface is insulated is laminated or spirally wound. This porous body has good heat transfer efficiency, heats a liquid or gas passing through the inside in a short time, and easily burns even a gas containing a lean gas or an unburned component. It is also used as an afterburner. And since it can manufacture easily compared with the conventional sintered compact, it is used in various fields as various heaters.
[Brief description of the drawings]
[Fig. 1] Press-formed metal plate or foil material [Fig. 2] Laminated metal plate or foil material [Fig. 3] Metal plate or foil material wound in a spiral shape [Fig. 4] Metal plate or adjacent burrs intertwined Foil material [Fig. 5] Metal plate or foil material wound in a double spiral shape [Fig. 6] Metal plate or foil material in a fold-like shape [Fig. 7] With adjacent surfaces (A) and (B) folded in a vine shape Waveform or unevenness with reversed wavefront direction [Explanation of symbols]
10: Metal plate or foil material 11: Corrugated or uneven 12: Yoke-shaped protrusion or burr 13: Through hole 14: Gap

Claims

波形又は凹凸状にプレス成形され、表面が絶縁処理された金属板又は箔材を隣接する面が相互に絶縁されるようにツヅラ折り状に積層した構造をもち、周縁にヨーク状突起又はバリをもつ貫通孔が前記波形又は凹凸状の山部又は谷部に穿設されている多孔体製の電気抵抗ヒータ。It has a structure in which a corrugated or uneven press-molded metal plate or foil material is laminated in a spiral fold so that adjacent surfaces are insulated from each other, with yoke-like protrusions or burrs on the periphery A porous electrical resistance heater in which through holes are formed in the corrugated or uneven peaks or valleys.

波形又は凹凸状にプレス成形され、表面が絶縁処理された金属板又は箔材を隣接する面が相互に絶縁されるように渦巻き状に巻き込んだ構造をもち、周縁にヨーク状突起又はバリをもつ貫通孔が前記波形又は凹凸状の山部又は谷部に穿設されている多孔体製の電気抵抗ヒータ。It has a structure in which corrugated or irregularly pressed metal plate or foil material is wound in a spiral shape so that adjacent surfaces are insulated from each other, and has a yoke-like protrusion or burr on the periphery A porous electric resistance heater in which a through hole is formed in the corrugated or uneven peak or valley.

金属板又は箔材に形成された波形又は凹凸の波面方向がツヅラ折りの方向又は渦巻き状の巻込み方向に対して傾斜している請求項１又は２記載の電気抵抗ヒータ。 The electric resistance heater according to claim 1 or 2, wherein a corrugated or uneven wave front direction formed on the metal plate or the foil material is inclined with respect to the direction of spiral folding or the spiral winding direction.

請求項１〜３の何れかに記載の金属板又は箔材として、Ｃｒ：８〜３０重量％，Ａｌ：８重量％以下，Ｔｉ：１重量％以下及びＭｏ：３重量％以下を含むＦｅ合金を使用した多孔体製の電気抵抗ヒータ。 An Fe alloy containing Cr: 8 to 30 wt%, Al: 8 wt% or less, Ti: 1 wt% or less, and Mo: 3 wt% or less as the metal plate or foil material according to any one of claims 1 to 3 An electrical resistance heater made of porous material.