Pressure filter for fibrous suspensions

Claim 1

A pressure device having two filters connected in parallel for filtering a liquid containing suspensions of fibrous material, comprising in combination: a. a housing including an upper housing section having a stock inlet and a lower housing section having a stock outlet; b. an inner upright filter basket disposed in said housing and supported by said lower housing section, said inner filter basket having a filtering surface, an upstream side and a downstream side; c. drive means secured to said housing; d. an inner vaned rotor disposed at the downstream side of said inner filter basket and operatively connected to said drive means; e. an outer filter basket arranged upright about said inner filter basket, said inner and outer filter baskets defining an annular space therebetween, said outer filter basket having a filtering surface; f. bypass means arranged at said annular space and defining a relatively large, non-filtering inflow aperture means adjacent said filtering surface of said outer filter basket, a first part of said liquid entering said stock inlet flowing through said bypass means and a second part of said liquid entering said stock inlet flowing through said filtering surface of said outer filter basket, said bypass means directing said first part of said liquid to flow into said annular space with the circumvention of the filtering surface of said outer filter basket; g. an outer vaned rotor situated in said annular space and operatively conNected to said drive means; and h. a partition in said annular space for directing said first part of said liquid onto the filtering surface of said inner filter basket and for directing said second part of said liquid to said downstream side of said inner filter basket with the circumvention of the filtering surface thereof.