Multiple-disc-filters

Claim 1

A filter including a housing having an inlet connectable to an upstream pipe, and an outlet connectable to a downstream pipe; and a stack of discs disposed within said housing for separating solid particles from a fluid flowing between said discs from the upstream side of said stack to the downstream side thereof; said stack comprising: a plurality of cooperating filter elements defining a plurality of paired co-operating filter surfaces, including a first surface defining a large surface area and a second surface contacting only a portion of said large surface area of said first surface and leaving a portion of the large surface area on the upstream side of the stack not contacted thereby, at least one of said first and second surfaces being formed with grooves at the areas at which said first and second surfaces contact, thereby to form: (a) compartments on the upstream side of the stack for accumulation of solid particles; and (b) edge filtering passageways extending along the grooves in contact with said second surface, which passageways define the minimum size of particles separated by the filter and extend from said compartments to the downstream side of the stack, wherein said second surface defined edges in a sinuous configuration.