IMPROVEMENTS IN SEAMED FILTER ELEMENTS

摘要

A method of joining a sheet of filter fabric to form a cylindrical or tubular filter element such as a centrifuge liner comprises overlapping the ends (10, 11) of the fabric (12), to form a seam, heating the ends (11, 12) in the seam to above the fusion temperature of a thermoplastic fabric using heated air from e.g. a nozzle (14), and pressing the ends (11, 12) together immediately after fusion using for example a presser roller (16). Alternatively heating may be by a curtain of hot air provided from an elongate slot which is applied to the full length of the seam simultaneously, and a presser shoe may be used in place of a roller. The tubular filter may be everted after fab)rication, and a bag filter formed by closure of one end with a disc of cloth.