Pressure filter having depending tubular filter elements

Claim 1

In a pressure filter of the type having depending tubular filter elements exposed to a pulp to be filtered under pressure, and delivering filtrate liquid from the upper open end, the combination which comprises a horizontal tube plate having holes for the insertion therein of tubular filter elements, a filter element inserted in said tube plate, which comprises a liquid-permeable rigid Tube having an upper open end provided with a flange, a filter sleeve having a closed end and an open end, surrounding said tube, and consisting of a filter media constructed and arranged so as to be radially expandable from its normal diameter, a ring of substantially non-deformable material, said ring having an inner diameter substantially equal to the diameter of the sleeve, inserted into said open end so that said media is stretched radially about said ring, accommodating the ring in a plane perpendicular to the longitudinal axis of the sleeve, the unstretched open end portion of the sleeve being turned inwardly through said ring, and connected peripherally to the adjoining surrounding portion of said sleeve thus forming an annular outwardly overhanging terminal bead at said open end, confined between said tube plate and said flange, retainer means engaging the top side of said flange, and means for securing said retainer means relative to said tube plate whereby said bead is compressed in such a manner that the filter media enveloping said ring provides a pair of annular compression seals effective between said ring and said tube plate, and between said ring and said flange respectively.

Claim 12

The method of making a filter sleeve for the prupose substantially such as herein described, which comprises, providing a length of filter cloth that is stretchable transversely of its longitudinal extent, interconnecting the longitudinal edge portion of said length of filter cloth in such a manner as to form a tubular shape representing a partly finished sleeve, closing one end of said tubular shape, providing a ring of substantially non-deformable material, and having an inner diameter substantially equal to the diameter of the sleeve, inserting and positioning said ring in the open end of said partly finished sleeve, whereby said filter cloth is radially stretched to accommodate said ring in a plane extending transversely of said sleeve, turning the unstretched free end portion of the filter cloth inwardly through the ring, and connecting said turned-in portion peripherally to the adjoining surrounding portion of the sleeve, so that there is formed a bead radially outwardly overhanging from said filter media.

Claim 13

The method of making a filter sleeve for the prupose substantially such as herein described, which comprises, providing a length of filter cloth that is stretchable transversely of its longitudinal extent, interconnecting the longitudinal edge portion of said length of filter cloth in such a manner as to form a tubular shape representing a partly finished sleeve, closing one end of said tubular shape, providing a ring of substantially non-deformable material, and having an inner diameter substantially equal to the diameter of the sleeve, inserting and positioning said ring in the open end of said partly finished sleeve, whereby said filter cloth is radially stretched to accommodate said ring in a plane extending transversely of said sleeve, turning the unstretched free end portion of the filter cloth inwardly through the ring, and connecting said turned-in portion peripherally to the adjoining surrounding portion of the sleeve, so that there is formed a bead radially outwardly overhanging from said filter media.