Filter plate-and-diaphragm assemblies for a filter press

In a filter plate-and-diaphragm assembly of the type including a filter plate having a base and a marginally extending frame, the frame having a sealing face;

• a pressure diaphragm having a dished base and a marginally extending sealing zone lying over the sealing face of the frame;
• the sealing zone including a sealing face oriented toward and adjoining the sealing face of the frame;
• means provided in said filter plate for introducing a pressure medium between the diaphragm base and the plate base;
• a portion of the diaphragm and a portion of the filter plate together defining between themselves and inwardly of the sealing zone, a pressure chamber for the pressure medium, the improvement comprising:
• a. means defining a groove in said frame;
• b. a rib forming part of said diaphragm and received in said groove, said rib being situated in said sealing zone adjacent an edge thereof, said edge being remote from said portions defining said pressure chamber, whereby said sealing face of said diaphragm being disposed between said rib and said portions defining said pressure chamber;
• c. means defining open channels on that side of the diaphragm base that is oriented away from the plate base;
• d. a truncated pyramidal portion forming part of said diaphragm and connecting said sealing zone of said diaphragm with the diaphragm base;
• and
• e. means defining a plurality of additional open channels in said truncated pyramidal portion, said additional open channels being oriented away from the plate base.