Asbestos coated fibrous cement pipe - entails stopping basic feed to felt belt whilst cement-fibre is placed downstream ensuring asbestos free internal lining

摘要

The process is used in the mfr. of asbestos cement pipes with an asbestos-free internal lining of fibre reinforced cement. A cylindrical filter in a bath contg. an aqueous suspension of asbestos and cement rotates to transfer a layer of this material to a felt belt transferring the layer to a pipe-former (3). The asbestos free fibre-cement mix is placed by a pivoting jack (9) actuated distributor (2) sited between the filter and the former. The formation of the asbestos cement layer is stopped by cleaning the filter with a spray bar (6) , thus, allowing fibre-cement to be deposited on a clean felt. Once the asbestos-free lining is complete the distributor is retracted and its feed stopped, the feed from the filter then recommencing. Fibres may be of cellulose, mineral or plastics based materials.