Types of Filter Plates

Filter press technology is a cornerstone of modern industrial filtration systems. Whether you work in mining, chemical processing, or wastewater treatment, selecting the right filter press plates can significantly impact your operational efficiency and product quality. In this blog post, we explore the three primary categories of filter press plates—recessed chamber, membrane squeeze (also known as diaphragm squeeze), and plate and frame—and discuss how each design serves specific industrial needs.

Recessed Chamber Filter Press Plates

Recessed chamber filter plates are the most commonly used type in many industrial applications. These plates are designed to work in a recessed chamber filter press system where they deliver excellent strength and higher fill pressure compared to other designs. One of the main advantages of these plates is their ability to create a virtually leak-free filtration process.

There are two distinct types within the recessed chamber category:

- CGR (Caulked, Gasketed, Recessed Chamber):  

  CGR filter plates utilize a specially designed filter cloth that is typically octagon shaped. A caulking rope or cord is sewn into the edge of the cloth, ensuring a tight seal that minimizes leakage. This feature is particularly important for operations that demand high levels of filtration integrity. The near leak-proof nature of CGR plates is a significant advantage, as it ensures consistent filtration performance even under high fill pressure.

- NG (Non-Gasketed):  

  In contrast, NG plates use a non-gasketed filter cloth which is simpler and faster to install. While this design expedites the setup process, it may lead to occasional dripping. However, for many applications, the ease of maintenance and quicker turnaround time can outweigh the slight risk of leakage.

These attributes make recessed chamber filter plates ideal for operations where durability, high pressure, and leak prevention are essential. They are widely adopted in industries where maintaining a sealed filtration environment is critical to the overall process.

Membrane Squeeze (Diaphragm Squeeze) Filter Press Plates

Membrane squeeze filter plates, also known as diaphragm squeeze plates, are engineered for specialized applications that require additional efficiency. Although these plates tend to be more costly than their recessed chamber counterparts, their performance benefits can justify the higher investment in many industrial scenarios.

The key benefit of using membrane squeeze plates lies in their ability to significantly enhance fluid removal. When the filter cake—the solid residue remaining after filtration—is compressible, these plates can achieve a higher degree of dryness in the filtered cake. This results in:

- Enhanced Fluid Removal:  

  The diaphragm mechanism compresses the filter cake, which is particularly useful when dealing with slurries that contain a higher-than-average amount of solids. By reducing the moisture content more effectively, membrane squeeze plates contribute to improved process efficiency.

- Cycle Time Reduction:  

  In many industrial settings, time is money. The membrane squeeze mechanism can reduce the overall cycle time by achieving quicker dewatering. This advantage is especially beneficial in high-volume operations where every minute counts.

- Adaptability to Variable Slurry Volumes:  

  Industries dealing with fluctuating slurry volumes can benefit from the flexibility offered by membrane squeeze plates. Their design allows them to handle variations in the volume and consistency of the slurry without compromising performance.

When the filter cake is compressible and the slurry characteristics demand rigorous dewatering, membrane squeeze filter plates become the preferred option despite their higher cost. This type of plate is recommended by many Sales and Service Teams for operations where the efficiency gains translate into substantial long-term savings.

Plate and Frame Filter Press Plates

The plate and frame design is the oldest among filter press plate configurations but still finds relevance in specific industrial applications. This traditional design remains popular for several reasons:

- Fine Filtration Capabilities:  

  Plate and frame filter presses are often used for fine filtration tasks, especially when filter paper is required. The design allows for the filter cloth to drape over the plate, making it suitable for applications that demand a high level of filtration fineness.

- Adjustable Filter Cake Thickness:  

  One notable advantage of the plate and frame system is the ability to control the thickness of the filter cake. By using a thicker or thinner frame, operators can customize the filtration process to suit the specific requirements of their operation.

- Low-Pressure Operation:  

  These filter presses generally operate at lower pressures, which can be beneficial for certain types of filtration where high pressure might damage the filter media or the material being processed.

However, this design is not without its drawbacks. Users should anticipate some leakage during the filtration process, which is a trade-off for its simplicity and versatility. Despite this, the plate and frame configuration is still widely used in applications such as polishing and the processing of specialty chemicals.

Conclusion

Selecting the right filter press plates is essential for optimizing industrial filtration systems. Each design offers unique benefits: recessed chamber plates provide durability and leak-free operation, membrane squeeze plates excel in efficiency and cycle time reduction for compressible filter cakes, and plate and frame systems offer versatility in fine filtration and adjustable cake thickness. By understanding the differences between these filter press plate types, engineers and operators can make informed decisions that enhance performance, reduce downtime, and ultimately drive operational success. Whether your priority is high pressure and durability or specialized dewatering capabilities, the right choice of filter press plate can make all the difference in achieving optimal industrial filtration results.