【発明の詳細な説明】[Detailed description of the invention]
本発明は加熱炉、均熱炉、あるいは焼鈍炉等比
較的高温度で使用される熱輻射型の炉における省
エネルギーを目的とした炉壁構造に関するもので
炉壁内面に溶融石英質せんいからなる断熱材を張
設し、その表面にβ型炭化珪素粉末を主成分とす
る炭化珪素質コーテイングを施して該コーテイン
グによる平滑な内表面を形成したことを特徴とす
るものである。
従来、炭化珪素の有する優れた耐火性と物理、
化学的性質に加え、その輻射特性に注目し、加熱
炉等の内壁等に被覆してこれを保護すると共にそ
の輻射性能を改善して所要熱エネルギーの節約を
図ることが提唱されており、（例えば特公昭47−
15088号、特開昭51−91916号、特公昭52−43732
号各公報）、一方、本出願人は特願昭53−79305号
において接着性、分散液安定性の良好な炭化珪素
質コーテイング材を提案しており、特に微細で活
性のあるβ型炭化珪素粉末、あるいは硼素成分を
炭化硼素に換算して10重量％まで均一な分散状態
で含有する微細で活性のあるβ型炭化珪素質粉末
を主要成分とする炭化珪素質コーテイング材は接
着性、分散液安定性に優れていることを示してい
る。
本発明は上記輻射特性に優れ、かつ接着性およ
び分散液安定性に優れたβ型炭化珪素粉末を主成
分とする炭化珪素質コーテイングを、断熱性を有
し、かつ熱膨張係数の極めて低い溶融石英質せん
いからなる断熱材と組合わせ使用して該断熱材の
表面にコーテイング材の平滑な面を形成し、加熱
炉等の省エネルギー効果をさらに高めるようにし
たものである。
次にその詳細を加熱炉等の炉壁断面の１例を示
す図について説明すると、１は外殻鉄皮、２は耐
火レンガ等のバツクライニングレンガ、３はその
内側に張設された例えばカオウール等の商品名で
市販されている溶融石英質せんいからなる断熱
材、４はその内面に施こされたβ型炭化珪素粉末
を主成分とする炭化珪素質コーテイング層であ
る。断熱材３は適当個所において図中ａに示すよ
うに外殻に固着したボルト５に螺合するナツト６
で止着し、あるいは同図ｂに示すように釘７でバ
ツクライニングレンガ２に止着して張設する。ナ
ツト６および釘７の頭部７′等の内面にはさらに
断熱材３を設け、断熱材３の内面がほぼ平滑にな
るようにすることが望ましい。断熱材３はバツク
ライニングレンガ２に接着してもよい。
溶融石英質せんいからなる断熱材の層３は５〜
100mm程度の厚さに設けるのが適当であり、この
範囲より薄くては断熱効果が充分に得られず、ま
た厚くては炉内容積が縮小されて操業上好ましく
ない。而してこの断熱材３の内面に上記β型炭化
珪素粉末を主成分とする炭化珪素質コーテイング
材４をその用途等に応じて0.1〜２mm程度の厚さ
に吹付け或いは刷毛塗り等によつて塗布するので
ある。
このようなコーテイング材を通常の耐火レンガ
２に直接塗布した場合、コーテイング層とレンガ
の熱膨脹の差により使用中コーテイング層が剥離
するおれがあるが、その間にせんい質断熱材３を
介在させ、この上に塗布した場合には、断熱材３
が融通性をもつているため膨脹差が緩和されて剥
離し難いという利点を有している。このコーテイ
ング材は前記特願昭53−79305号に示す如き微細
で（約20μｍ以下）、活性が大きなβ型炭化珪素
粉末に適量の粘結剤を混合したもので、微粒子で
活性を有するため接着性が極めて良好であり、せ
んい質断熱剤３のような粗面にもよく接着して極
めて平滑な表面が得られ、また上述のように断熱
材３に溶融石英質せんいを使用したので熱による
膨張収縮、歪み等が極めて少なく、従つて上記β
型炭化珪素粉末の接着性の良好なことと相俟つて
平滑度の極めて高い内表面が常に安定した状態で
得られ、反射性能が良好となり、輻射性能を一層
高めることができる。またこのコーテイング液は
上述の如く分散液の安定性に優れているので長期
間保存した場合でも固形分と液との分離がなく、
コーテイングの使用に供することができる効果も
有している。
上述の如く本発明によれば、炉内に対しては炭
化珪素質コーテイング層４の高い輻射能によつて
輻射加熱効果を高め、外部に対してはせんい質断
熱材３により伝熱損失を防ぐので、優れた省エネ
ルギー効果を有する炉壁構造を得ることができ
る。
実施例 １
幅２ｍ，高さ２ｍ，奥行12ｍの焼鈍炉の天井お
よび炉壁内面に溶融石英質せんいからなる断熱材
を約３cmの厚さに張り、その表面にβ型炭化珪素
粉末（粒度100μｍ以下）50重量部、ベントナイ
ト４重量部、水50重量部の割合で混合して得られ
た分散液コーテイング材をガン吹付けにより厚さ
約0.1〜0.2mm塗布した。この際、分散液の使用量
は約18Kgであり、塗布面積は約80m2であつた。
この焼鈍炉を1000℃で操業したところ、施工前
に比べて20.5％の省エネルギー効果が達成され
た。
実施例 ２
内径３ｍ，高さ５ｍのベル型焼鈍炉（焼鈍温度
1100℃において前例と同様の断熱材、コーテイン
グ材を各単独に施工した場合、および両者を併用
施工した場合の各省エネルギーの程度をそれぞれ
施工前と比較した結果、次表に示す値が得られ
た。
The present invention relates to a furnace wall structure for the purpose of energy saving in thermal radiation type furnaces used at relatively high temperatures such as heating furnaces, soaking furnaces, or annealing furnaces. The material is stretched, and a silicon carbide coating containing β-type silicon carbide powder as a main component is applied to the surface of the material to form a smooth inner surface. Conventionally, silicon carbide has excellent fire resistance and physical properties,
In addition to its chemical properties, attention has been focused on its radiation properties, and it has been proposed to protect the inner walls of heating furnaces, etc., and to improve its radiation performance and save the required thermal energy. For example, the special public official court in 1977-
No. 15088, JP 51-91916, JP 52-43732
On the other hand, the present applicant has proposed a silicon carbide coating material with good adhesiveness and dispersion stability in Japanese Patent Application No. 79305/1983, and in particular, the present applicant has proposed a coating material based on silicon carbide with good adhesion and dispersion stability. The silicon carbide coating material whose main component is powder or fine active β-type silicon carbide powder containing up to 10% by weight of boron carbide in a uniformly dispersed state has adhesive properties and a dispersion liquid. This shows that it has excellent stability. The present invention uses a silicon carbide coating mainly composed of β-type silicon carbide powder, which has excellent radiation properties, adhesive properties, and dispersion stability, and which has thermal insulation properties and an extremely low coefficient of thermal expansion. When used in combination with a heat insulating material made of quartz fiber, a smooth surface of the coating material is formed on the surface of the heat insulating material, thereby further enhancing the energy saving effect of heating furnaces, etc. Next, the details will be explained with reference to a diagram showing an example of a cross section of a furnace wall of a heating furnace, etc., 1 is an outer shell, 2 is a back lining brick such as a refractory brick, and 3 is a wall covered with, for example, Kao wool. A heat insulating material made of fused silica fiber is commercially available under the trade name 4. A silicon carbide coating layer containing β-type silicon carbide powder as a main component is applied to the inner surface of the heat insulating material. The heat insulating material 3 is fitted with a nut 6 screwed onto a bolt 5 fixed to the outer shell at an appropriate location as shown in a in the figure.
or, as shown in FIG. It is desirable that a heat insulating material 3 is further provided on the inner surfaces of the nuts 6, the heads 7' of the nails 7, etc., so that the inner surfaces of the heat insulating materials 3 are substantially smooth. The heat insulating material 3 may be adhered to the back lining brick 2. The layer 3 of the heat insulating material made of fused silica fiber is 5~
It is appropriate to provide a thickness of about 100 mm; if it is thinner than this range, a sufficient heat insulating effect cannot be obtained, and if it is thicker, the internal volume of the furnace will be reduced, which is not favorable for operation. Then, a silicon carbide coating material 4 containing the above-mentioned β-type silicon carbide powder as a main component is applied to the inner surface of this heat insulating material 3 to a thickness of about 0.1 to 2 mm depending on the application etc. by spraying or brushing. Then apply it. When such a coating material is directly applied to ordinary firebricks 2, the coating layer may peel off during use due to the difference in thermal expansion between the coating layer and the bricks. If applied on top, insulation material 3
It has the advantage that the difference in expansion is alleviated and it is difficult to peel off because it has flexibility. This coating material is made by mixing an appropriate amount of a binder with fine (approximately 20 μm or less) and highly active β-type silicon carbide powder as shown in the above-mentioned Japanese Patent Application No. 53-79305. It has extremely good properties and adheres well to rough surfaces such as the siliceous insulation material 3, resulting in an extremely smooth surface.Also, as mentioned above, since fused silica fiber is used for the insulation material 3, it is resistant to heat damage. Expansion/contraction, distortion, etc. are extremely small, so the above β
Coupled with the good adhesion of the molded silicon carbide powder, an extremely smooth inner surface can be obtained in a stable state at all times, resulting in good reflection performance and further enhanced radiation performance. In addition, as mentioned above, this coating liquid has excellent dispersion stability, so even when stored for a long period of time, there is no separation of solid content and liquid.
It also has the effect of being able to be used as a coating. As described above, according to the present invention, the radiation heating effect is enhanced for the inside of the furnace by the high radiation efficiency of the silicon carbide coating layer 4, and heat transfer loss is prevented for the outside by the siliceous insulation material 3. Therefore, a furnace wall structure having an excellent energy saving effect can be obtained. Example 1 A heat insulating material made of fused silica fiber was placed approximately 3 cm thick on the ceiling and inner surface of the furnace wall of an annealing furnace measuring 2 m wide, 2 m high, and 12 m deep, and β-type silicon carbide powder (particle size 100 μm) was applied to the surface. A dispersion coating material obtained by mixing 50 parts by weight of Bentonite, 4 parts by weight of bentonite, and 50 parts by weight of water was applied to a thickness of about 0.1 to 0.2 mm by gun spraying. At this time, the amount of dispersion used was about 18 kg, and the coating area was about 80 m 2 . When this annealing furnace was operated at 1000℃, an energy saving effect of 20.5% was achieved compared to before construction. Example 2 Bell-shaped annealing furnace with an inner diameter of 3 m and a height of 5 m (annealing temperature
As a result of comparing the degree of energy saving when the same insulation and coating materials as in the previous example were applied individually and when both were applied together at 1100℃, the values shown in the following table were obtained. .
【表】
実施例 ３
幅550mm，高さ600mm，長さ1500mmのウオーキン
グビーム炉の天井および内壁に溶融石英質せんい
からなる断熱材を約５cmの厚さに張り、その表面
に粒度が20μｍ以下のβ型炭化珪素粉末（平均粒
度1.5μｍ）50重量％、微粉シリカ（平均粒度１
μｍ以下）1.0重量％、ベントナイト4.0重量％、
水が残部（45重量％）からなる配合物を混合撹拌
して得た分散液状の炭化珪素質コーテイング材を
スプレーガンで約0.2〜0.3mmの厚さに塗布した。
この際のコーテイング材の使用量は800gr、塗布
面積は３n２であつた。施工後、1150℃までの昇
温時間が28％短縮し、重油の消費量が約25％節減
でき、顕著な省エネルギー効果が示された。
以上の各実施例によつても本発明の炉壁構造は
省エネルギー効果の顕著なことが明らかである。[Table] Example 3 The ceiling and inner walls of a walking beam furnace with a width of 550 mm, a height of 600 mm, and a length of 1500 mm are covered with an insulating material made of fused silica fibers to a thickness of approximately 5 cm, and on the surface of β-type silicon carbide powder (average particle size 1.5 μm) 50% by weight, fine powder silica (average particle size 1
μm or less) 1.0% by weight, bentonite 4.0% by weight,
A silicon carbide coating material in the form of a dispersion obtained by mixing and stirring a formulation consisting of water as the balance (45% by weight) was applied to a thickness of about 0.2 to 0.3 mm using a spray gun.
The amount of coating material used at this time was 800gr, and the coating area was 3n2 . After construction, the time required to raise the temperature to 1150℃ was shortened by 28%, and heavy oil consumption was reduced by approximately 25%, demonstrating a significant energy-saving effect. It is clear from each of the above examples that the furnace wall structure of the present invention has a remarkable energy saving effect.
【図面の簡単な説明】[Brief explanation of the drawing]
図面は本発明炉壁構造の一実施例を示す断面図
である。
１……外殻鉄皮、２……バツクライニングレン
ガ、３……せんい質断熱材、４……炭化珪素質コ
ーテイング層。
The drawing is a sectional view showing an embodiment of the furnace wall structure of the present invention. 1... Outer shell iron shell, 2... Cross lining brick, 3... Silica insulation material, 4... Silicon carbide coating layer.