Isolite Babcock Refractories Co., Ltd.

Shigezo Udaka

Takeo Kato

Hideo Yamagata

Norihiro Tsukagoshi

Noriyuki Kitamoto

Kazuo Sonobe

A novel .beta.-amylase gene is provided. This gene is useful for production of a thermophilic .beta.-amylase obtained from Clostridium thermosulfurogenes on a large scale, especially from genetically engineered microorganisms introduced with this gene. B. subtilis was transformed with a plasmid pNK1 containing the above gene and the transformed B. subtilis cells produced .beta.-amylase having the same thermostability as that of .beta.-amylase obtained from C. thermosulfurogenes.

.beta.-amylase gene

Each ceramic fiber block is temporarily supported by a supporting member and bar combination previously secured to the furnace casing, before it is finally secured to the casing by another supporting member and bar combination. No separate means for holding the block temporarily is required. As ceramic fiber blocks and supporting members are alternately attached to the casing, it is possible to ensure intimate contact between every two adjoining blocks. The absence of any extra work for holding the blocks temporarily improves the efficiency of the block installation work.

Method of installing ceramic fiber blocks

Fibrous insulating material consisting of a rectangular or semi-cylindrical block obtained by stacking ceramic fiber blankets or felt in the thickness direction thereof and bonding contact surfaces of adjacent blankets or felt to each other with an adhesive. Such insulating fire material is bonded to the furnace surface such that the bonded surfaces are perpendicular to the wall surface. By using the fibrous insulating material which is ready to handle, it is possible to facilitate and reduce time required for construction of the insulating wall.

Fibrous insulating material and insulating wall

A ceramic fiber felt is obtained by mixing alumina crystalline ceramic fibers having at least about 60 weight percent of Al.sub.2 O.sub.3, the rest being SiO.sub.2 and impurities, and having a filament length ranging from 10 to 30 mm with aluminosilicate non-crystalline ceramic fiber having from about 40 to 70 weight percent of Al.sub.2 O.sub.3, the rest being primarily SiO.sub.2, impurities, and, optionally, including a small amount of metal oxides, and having a filament length ranging from 5 to 30 mm, the weight proportions of the alumina crystalline ceramic fibers to the aluminosilicate non-crystalline ceramic fiber being from about 4:6 to 7.5:2.5, and preferably from about 4:6 to 5:5, and binding the mixture of components with an organic binder. The ceramic fiber felt having a linear percentage shrinkage at 1400.degree. C. of only about 2% is very inexpensive compared to alumina ceramic fiber and is highly suited for use as or in furnace linings.

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Aichi, Japan

Takeo Kato