B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
B28B21/00—Methods or machines specially adapted for the production of tubular articles
B28B21/42—Methods or machines specially adapted for the production of tubular articles by shaping on or against mandrels or like moulding surfaces
B—PERFORMING OPERATIONS; TRANSPORTING
B28—WORKING CEMENT, CLAY, OR STONE
B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
B28B21/00—Methods or machines specially adapted for the production of tubular articles
B28B21/42—Methods or machines specially adapted for the production of tubular articles by shaping on or against mandrels or like moulding surfaces
B28B21/44—Methods or machines specially adapted for the production of tubular articles by shaping on or against mandrels or like moulding surfaces by projecting, e.g. spraying