Process for manufacturing large-size porous shaped bodies of low density by swelling

A process of manufacturing large-size porous shaped bodies of low density by swelling clay masses by supplying heat thereto, comprising the steps of

• introducing an unswollen plate-like, self-supporting clay mass in the form of a thin, compact clay slab
• into a furnace and suddenly continuously rapidly swelling the slab by heat supplied exclusively from above and below at a maximum furnace temperature which remains constant from the beginning to the end of the swelling;
• subjecting the surface of the swelling clay mass to constant oxidation by supply of oxidizing hot gases to the surface of the clay slab;
• giving the swelling clay slab a support by direct-acting, multiple linear solid body contact, while maintaining the swelling clay slab in constant motion relative to the support, said support being effected by rollers being rotatably arranged below, above and on both sides of the swelling clay slab;
• said introducing of said clay slab into said furnace being effected by driving said rollers;
• guiding the clay slab during its movement through said furnace by said rollers in the downward and lateral directions in an unyieldable manner, while yieldably guiding the clay slab in the upward direction;
• counting the yielding of the swelling clay slab upwards during increasing of its height by an adjustable structure-stabilizing counter-force against a swelling-force;
• using said adjustable counter-force for variable geometrical expansion of the swelling mass for controlling the swelling process,
• said controlling of the swelling process including creating an isostatic pressure controlled so that shaping occurs during the swelling by top rollers above the swelling clay mass to provide a fine distribution of pores,
• said guiding of the clay slab including supporting the swelling mass on all other sides so that at a rear it is supported by an unswollen clay mass, which is held by means of frictional resistance by rollers and at the front it is supported by an already swollen clay mass which is held by means of frictional resistance by rollers.