Filter press with alternating diaphragm squeeze chamber plates and filtration chamber plates

In a filter press having a frame including a pair of generally horizontally elongated and parallel side rails which are disposed in sidewardly spaced relation, first and second head assemblies mounted on said frame adjacent opposite ends of said side rails, said first head assembly being disposed adjacent one end of said side rails and supported for movement horizontally in a lengthwise direction of the side rails forwardly toward and rearwardly away from said second head assembly so as to be respectively positioned in closed and opened positions, said second head assembly being stationarily positioned adjacent the other end of said side rails, a plate arrangement including a plurality of individual plates supported on and between said side rails for movement therealong between said first and second head assemblies, said plurality of plates being pushed together into a horizontally extending closed stack and clampingly held between said first and second head assemblies when said first head assembly is moved toward said second head assembly into said closed position, a plate shifting arrangement for effecting individual and sequential shifting of said plates from said closed stack along said side rails in said rearward direction toward said first head assembly when in the open position, comprising the improvement wherein:

• said plurality of plates comprises a plurality of first plates each including a frame having a pair of oppositely disposed parallel faces, a peripheral edge portion surrounding a central portion having two sides which face away from one another and are recessed inwardly towards a central plane of said first plate with respect to said peripheral edge portion, said peripheral edge portion having first and second side surfaces facing away from one another and each defining therein a continuous groove, a first liquid impermeable membrane extending across one of said sides of said central portion to define a first pressure chamber therewith and a second liquid impermeable membrane extending across the other said side of said central portion to define a second pressure chamber therewith, each said first and second membrane having an outer periphery with a terminal edge engaged within a respective one of said grooves and fixed therein by an elastomeric retaining member which overlies the respective said membrane and holds said terminal edge thereof in said groove;
• said plurality of plates comprises a plurality of second plates each including a frame having a pair of oppositely disposed parallel faces, a peripheral edge portion surrounding a central portion having two sides which face away from one another and are recessed inwardly towards a central plane of said second plate with respect to said peripheral edge portion of said second plate, a first liquid permeable filter member fixed to said frame of said second plate and extending across one of said sides of said central portion of said second plate to define a first drainage chamber therewith in fluid communication with a filtrate discharge passage, and a second liquid permeable filter member fixed to said frame of said second plate and extending across the other said side of said central portion of said second plate to define a second drainage chamber therewith in fluid communication with a filtrate discharge passage, each said second plate being free of liquid impermeable membranes;
• and
• said first and second plates being disposed in an alternating manner along said side rails in adjacent contact with one another in said closed position to define a filter chamber therebetween for filtering and collecting solids from a slurry entering said filter chamber, said first and second side surfaces each having an annular planar portion which extends from an outer perimeter of the corresponding said pressure chamber to the respective said groove, said outer peripheries of said first and second membranes respectively extending over said planar portions such that said outer peripheries are clamped between and in direct contact with said planar portions and the peripheral edge portions of the adjacent said second plates to seal therebetween in said closed position, the liquid portion of the slurry from said filter chambers penetrating said filter members of said second plates, entering said first and second drainage chambers and exiting said filter press via a filtrate discharge passage and the solid portion of the slurry remaining in said filter chambers, said first and second pressure chambers being in fluid communication with a fluid source to expand said first and second membranes toward an adjacent one of said first and second filter members and pressurize the slurry to facilitate liquid solid separation.