| 摘要 |
39 Process and apparatus for the manufacture of large-size porous shaped bodies of low density by swelling In order to manufacture large-size porous coarse ceramic shaped bodies of low density, a clay-mineral mass of substances which are naturally swellable or are made swellable, such as basalts, pearlites, shales and clays, are uniformly swollen by means of thermal, chemical and mechanical treatment. Plate-like dried, and, if necessary, pre-heated thin compact clay masses are supported on all sides by rollers with gaps therebetween, so as to be incapable of expansion laterally and downwardly and expansible only upwardly in the course of the swelling. The mass is supported at the rear by the unswollen clay mass which is held by means of frictional resistance, and at the front by the already-swollen clay mass which is also held by means of frictional resistance. By supplying heat from above and below between the rollers and by supplying oxidizing gases to the surfaces of the plate-like clay masses, they are heated and swollen until a plate-like shaped body of the desired low density is formed. By this means one achieves high speed and uniformity of the heating during the swelling operation without caking of the swelling clay mass on the apparatus, a high shape stability of the clay mass during swelling with small forces needed for the shaping and the conveyance of the swelling clay mass, and hence largesize shaped bodies with a uniformly low density and also uniform and high porosity, strength and shape precision which are capable of being manufactured economically.
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