Patent ID: 6911168

Claim:
A method of manufacturing a right cylindrical body by molding a settable loose granular composition in a mold cavity, in which method a right cylindrical mold cavity is used having dimensions in right section equal to the right section of the body to be made, and said cavity is fed with a controlled rate of flow of successive charges of the composition in the loose state, in which said feeding is performed in such a manner that at all times the composition in place in the cavity presents a free surface and each new charge is deposited on a zone of said free surface, and each new charge is thrust into said surface by means of thrust surfaces that are moved both in reciprocating motion directed towards and away from said free surface, and in cyclical motion such that the thrust surfaces are moved over the extent of the free surface, and simultaneously during molding, relative displacement is implemented between the molded composition and the thrust surfaces, the method being characterized in that each new charge is thrust in such a manner that on each individual stroke of a thrust surface, the underlying composition is caused to interpenetrate over a depth that is not less than five times the mean diameter of the grain size of the coarsest ingredients of the composition, in that said relative displacement is performed in such a manner as to maintain a substantially constant distance between said free surface and the mean point of the stroke of the reciprocating motion of the thrust surfaces, and in that the flow rate of said charges is controlled in such a manner that during each cycle the material onto which the charges are deposited becomes progressively densified in depth by the cumulative interpenetration of the charges, conditions being adjusted in such a manner that over all of the cycles, this densification is substantially uniform throughout the material, and the molded composition is allowed to set.