Filter plates are the core working components of a filter press. They determine how slurry enters the press, how solids are retained, how filtrate is discharged, and how dry the final filter cake can become. Although filter plates may look similar from the outside, different plate designs can lead to very different filtration results. For buyers, engineers, and plant operators, understanding the main types of filter plates is the first step toward choosing the right solution for wastewater treatment, mining, chemical processing, food production, and other industrial filtration applications.
In general, filter plates can be classified by structure, squeezing function, sealing method, material, and customization requirements. The most common types include recessed chamber filter plates, membrane filter plates, plate and frame filter plates, CGR filter plates, gasketed and non-gasketed plates, PP filter plates, rubber membrane plates, and custom filter plates. Each type has its own advantages and is designed for different operating conditions.
Recessed Chamber Filter Plates
Recessed chamber filter plates are one of the most widely used types in modern filter presses. Each plate has a recessed area on both sides. When two plates are pressed together, these recessed areas form a chamber where slurry enters and solids accumulate. As filtration continues, liquid passes through the filter cloth and drainage surface, while solids remain inside the chamber to form a filter cake.
The main advantage of recessed chamber plates is their simple and reliable structure. They are suitable for many standard solid-liquid separation processes, including municipal sludge dewatering, industrial wastewater treatment, mining tailings, chemical slurry filtration, and general process filtration. Compared with older plate and frame designs, recessed chamber plates are easier to operate and usually provide better stability under pressure.
However, recessed chamber plates have a fixed chamber volume. Once the chamber is full, the filtration cycle must stop and the cake must be discharged. For materials that are difficult to dewater, the final cake moisture may be higher than what a membrane plate can achieve. Therefore, recessed chamber filter plates are often selected when the process requires stable performance, moderate cake dryness, and cost-effective operation.
Longone supplies recessed chamber filter plates in different sizes, chamber depths, feed positions, discharge designs, and materials. For many customers replacing old filter plates, recessed chamber plates are often the first option to consider because they are widely compatible with different filter press systems.
Membrane Filter Plates
Membrane filter plates, also known as diaphragm filter plates, are designed for applications that require lower cake moisture and shorter filtration cycles. Unlike standard recessed plates, membrane plates include a flexible diaphragm or membrane on the filtration surface. After the initial feeding and filtration stage, compressed air or water is introduced behind the membrane. The membrane expands and squeezes the filter cake, forcing out additional liquid.
This secondary squeezing process is the main reason membrane filter plates are used in more demanding dewatering applications. They can help reduce cake moisture, improve filtration efficiency, shorten cycle time, and increase overall production capacity. In some industries, a drier cake means lower transportation cost, easier disposal, better product recovery, or improved downstream processing.
Membrane plates are commonly used in wastewater sludge treatment, mining and mineral processing, chemical production, food processing, and applications where the filtered solids still contain valuable materials. They are especially useful when the slurry is difficult to dewater by pressure filtration alone.
The main limitation is that membrane plates usually cost more than standard chamber plates. They also require proper pressure control and suitable membrane material selection. If the membrane is exposed to excessive pressure, incompatible chemicals, or improper operation, its service life may be shortened. Therefore, buyers should consider operating pressure, slurry characteristics, chemical resistance, temperature, and maintenance requirements before choosing membrane plates.
Longone provides membrane filter plates and rubber membrane plates for different industrial conditions. Depending on the process, the plates can be customized in size, material, membrane design, feed hole position, and sealing structure.
Plate and Frame Filter Plates
Plate and frame filter plates are a traditional filter press design. In this structure, plates and frames are arranged alternately. The frame creates the chamber space for holding solids, while the plate supports the filter cloth and allows filtrate to pass through. This design was widely used in earlier filter press systems and is still used in some specific filtration processes today.
The advantage of plate and frame filter plates is flexibility. Different frame thicknesses can be used to create different cake thicknesses. This can be useful in applications where the process requires special cake volume or where existing equipment was originally designed for plate and frame operation.
However, compared with recessed chamber plates, plate and frame systems usually have more components, which may increase handling, maintenance, and cloth installation work. For many modern industrial filter presses, recessed chamber plates have become more common because of their integrated chamber design and simpler operation.
Longone can supply plate and frame filter plates for replacement, maintenance, or customized filter press projects. For customers operating older equipment, providing plate size, frame thickness, feed position, and photos or drawings can help confirm the correct replacement design.
CGR Filter Plates
CGR filter plates are caulked, gasketed, and recessed filter plates. They are a special type of recessed chamber plate with a gasket installed around the sealing surface. The purpose of the gasket is to create a tighter seal between adjacent plates and reduce leakage during filtration.
CGR plates are especially useful when leakage control is important. In some applications, even small dripping between plates can cause workplace contamination, product loss, safety concerns, or additional cleaning work. For chemical filtration, food processing, pharmaceutical-related filtration, corrosive slurry handling, and clean wastewater treatment, CGR plates can provide a cleaner and more controlled filtration process.
Compared with non-gasketed recessed plates, CGR plates usually require more attention during cloth installation and gasket maintenance. The gasket material should also match the slurry and operating conditions. Common gasket materials include EPDM, NBR, Neoprene, and FKM/Viton, depending on chemical compatibility, temperature, and sealing requirements.
Longone offers CGR filter plates with customized sealing structures and gasket options. For customers who need near-zero leakage, improved filtrate cleanliness, or better working environment control, CGR filter plates are often a strong choice.
Gasketed vs Non-Gasketed Filter Plates
Besides the main structural types, filter plates can also be divided into gasketed and non-gasketed designs. Gasketed plates use a sealing gasket around the filtration area, while non-gasketed plates rely mainly on plate-to-plate contact and filter cloth installation.
Gasketed plates are suitable for applications where leakage control, clean operation, and filtrate containment are important. They are often used with CGR designs. Non-gasketed plates are simpler and may allow faster cloth replacement, making them suitable for operations where minor wicking or dripping is acceptable and maintenance speed is more important.
The choice depends on the working environment, slurry properties, cleanliness requirements, and maintenance preference. A chemical plant, for example, may prefer gasketed plates, while a general sludge dewatering process may use non-gasketed recessed chamber plates.
Filter Plate Materials
Material selection is just as important as plate type. Polypropylene, or PP, is one of the most common materials for filter press plates because it is lightweight, corrosion-resistant, and suitable for many industrial applications. Glass fiber reinforced PP can provide higher strength and better stability under demanding conditions. PVDF is often selected for more aggressive chemical environments. Stainless steel and cast iron plates may be used in special high-temperature, high-pressure, or heavy-duty applications.
Longone provides PP filter plates and other material options for different industries. When choosing a material, buyers should consider slurry pH, temperature, pressure, chemical composition, filtration cycle, and expected service life.
Custom Filter Plates
Not every filter press uses a standard plate. Many customers need custom filter plates because they are replacing plates from an old filter press, matching a specific brand, changing cake thickness, modifying the feed position, or improving the drainage surface.
For a custom filter plate quotation, buyers should prepare key information such as plate size, plate thickness, chamber depth, feed hole position, filtrate discharge type, operating pressure, operating temperature, material requirement, gasket type, and photos or drawings of the existing plate. The more accurate the information, the easier it is to produce a compatible replacement plate.
Longone manufactures custom filter plates for different filter press systems. The available options include recessed chamber plates, membrane plates, CGR plates, plate and frame plates, PP plates, rubber membrane plates, and special-size filter plates. Longone can support standard and custom sizes, different chamber depths, center feed or corner feed designs, open or closed filtrate discharge, and gasketed or non-gasketed sealing structures.
How to Choose the Right Filter Plate
There is no single best type of filter plate. The right choice depends on the actual filtration process. For general sludge dewatering and solid-liquid separation, recessed chamber filter plates are usually a reliable and economical option. For lower cake moisture and higher efficiency, membrane filter plates are often more suitable. For leakage-sensitive applications, CGR or gasketed plates should be considered. For older equipment or special filtration requirements, plate and frame or custom filter plates may be required.
Before purchasing filter plates, it is important to review the slurry characteristics, operating pressure, temperature, chemical compatibility, cake dryness requirement, maintenance method, and filter press model. A correctly selected filter plate can improve filtration performance, reduce downtime, extend service life, and lower the total operating cost.
If you are replacing filter press plates or selecting plates for a new filtration project, Longone can help confirm the suitable plate type, material, sealing design, and dimensions based on your working conditions. With a complete range of chamber, membrane, CGR, plate and frame, PP, rubber membrane, and custom filter plates, Longone provides practical solutions for industrial filtration applications worldwide.