Recessed chamber and diaphragm (membrane). These are the two types of filter plates used in most dewatering applications. The plates are quite different in their design and application. Read on to learn which type of filter plate will be best for your dewatering application.
Recessed Chamber Filter Plates
Recessed chamber plates are a fixed volume plate, meaning they can only handle so much filter cake at a time. How do these particular filter plates work? When two of the plates are pressed together a cavity (or recessed chamber) is created between them where the filter cake has room to collect. A filter cloth is stretched across each plate to retain the filter cake. The cake is not suspended in a frame as it is with a conventional plate and frame, so it is easily discharged when the press is opened.
Recessed chamber plates are the standard plate used in most applications. They are the most commonly used type of plate because they offer flexibility with a wide range of cake thicknesses and limited maintenance. One of the primary reasons they require little maintenance is because they are made of extremely sturdy materials, typically corrosion resistant polypropylene.
Diaphragm (membrane) Filter Plates
Diaphragm (or membrane) plates feature flexible drainage surfaces that expand to exert additional pressure on the filter cake, eliminating even more moisture than conventional or recessed chamber plates. As a result, diaphragm filter plates offer higher production rates for compressible slurries or slurries that require a cake wash or cake blow.
Diaphragm plates are used in applications where the filter cake is a soft material or the solids do not pack closely together. For example if the filter cake is made up of plant or fibrous materials. Diaphragm plates can also be used in applications (like mining) where the filter cake requires washing. In these cases, the filter cake can be squeezed by the diaphragms while simultaneously being washed.
Typically, the plates themselves are made of corrosion resistant polypropylene and the diaphragms are made of PP, PVDF, Nylon or EPDM.
Well maintained filter plates and filter cloths are a crucial part of an effective, efficient dewatering system. To learn some cleaning tips and tricks download our guide, FAQ's for Filter Press Process, Operations & Maintenance.