摘要 |
An edge filter comprises a stack of annular plastics discs, each having a flat face which is pressed into contact with the opposed ribbed face of the next disc. The ribbed face of each disc has an array of radial ribs 44', the inner and outer ends of alternate pairs of ribs being joined by short arcuate ridges 42 and 43. The ridges are higher than the radial ribs and serve to space the discs apart, while the ribs and the flat face of the adjacent disc define radially extending filtering gaps between them, separating radial inlet spaces 40 from radial outlet spaces 41. The entrances to inlet spaces 40 may trap large particles. The stack is located in a housing (Fig. 1 not shown) with a spring compressing the stack. Reverse flow acts on the spring to allow the discs to separate during cleaning. <IMAGE> |