The plate and frame filter press, as a classic type of plate filter press (composed of filter plates and filter frames alternately arranged to form a filter chamber), has long occupied an important position in the field of solid-liquid separation due to its unique structural design and filtration principle.
Its advantages are mainly reflected in the following aspects:
1. high filtration accuracy, complete separation of solid and liquid
The filter chamber structure has strong airtightness and excellent retention effect. The filter plate and filter frame of the plate and frame filter press are tightly pressed through the hydraulic system to form an independent closed filter chamber. When the material is filtered through the filter cloth under pressure, the solid particles are strictly trapped in the filter chamber, and the liquid is discharged through the gap of the filter cloth. This structure has a rejection rate of more than 98% for fine particles (such as pigments, dyes, catalysts) and colloidal materials, and the filtrate has high clarity (turbidity is usually less than 10NTU), far exceeding some continuous filtration equipment (such as rotary drum filters).
High-pressure filtration is suitable for high-viscosity materials. The filtration pressure can be stably maintained at 0.6-1 MPa, which can effectively handle materials with high viscosity and high solid content (20% -60%) (such as chemical sludge, starch residue, food processing waste residue). Compared with the belt filter press, its filtration efficiency for non-fluid or easily compressible materials is higher, and it is not easy to cause problems of "running material" or incomplete filtration.
2. the filter cake has low moisture content and low follow-up treatment costs
The filter chamber of the plate and frame filter press is formed by the filter plate and the filter frame to form a fixed volume space. As the filtration proceeds, the filter cake in the filter chamber is gradually filled and compacted. With the "extrusion dehydration" action under high pressure, the moisture content of the filter cake can be as low as 15% -30% (depending on the material characteristics).
For example:
The water content of municipal sludge can be reduced from more than 95% to less than 30% after being filtered by plate and frame, and the volume can be reduced by more than 70%, which greatly reduces the cost of transportation, landfill or incineration.
After the mine tailings are pressed and filtered, the filter cake can be directly used as a building backfill material without secondary drying.
3. Simple and durable structure, low maintenance cost
Fewer core components, low failure rate, mainly composed of filter plate, filter frame, filter cloth, hydraulic system and frame, no complex rotating or transmission parts (such as centrifugal filter drum, belt filter press roller), daily wear is concentrated in filter cloth and sealing gasket, easy to replace and low cost (filter cloth can be selected according to the material polyester, polypropylene and other materials, the unit price is much lower than the precision mechanical parts).
Strong material adaptability and long service life. Reinforced polypropylene (PP), cast iron, stainless steel and other materials can be selected for filter plates and frames:
PP material acid and alkali resistance, light weight, suitable for chemical, environmental protection and other corrosive conditions;
Stainless steel/cast iron has high strength and can withstand high pressure and high temperature materials (such as high temperature slurry filtration), with a service life of up to 5-10 years.
4. Flexible operation, adaptable to multi-scenario requirements
Intermittent operation is convenient for process control. The intermittent process of "feed → filtration → pressure holding → cake unloading" is adopted, and the separation effect can be optimized by adjusting the filtration time and pressure parameters. It is especially suitable for small batch and multi-variety material processing (such as filtration after fine chemical batch reaction, laboratory small test or pilot test). During production, it can be flexibly started and stopped according to the material characteristics to avoid the efficiency decline caused by continuous equipment due to feed fluctuations.
Specifications can be customized, from small to large full coverage, filter plate size from 320mm × 320mm (laboratory use) to 2000mm × 2000mm (industrial large equipment), filter area can be expanded from 0.5 square meters to more than 1000 square meters, both to meet the low production demand of small workshops, but also to adapt to large-scale production of large factories (such as metallurgy, mining 10,000-ton solid-liquid separation line).
High filtrate collection rate and excellent resource utilization rate
The closed filter chamber design of the plate and frame filter press can reduce the waste of the filtrate. For the filtrate containing high-value components (such as solvents in chemical reactions and juices in food processing), it can be efficiently recycled and reused to reduce the loss of raw materials. For example: in the pharmaceutical industry, the plate and frame filter press can recover the active ingredients in the fermentation liquid and improve the product yield; in the dye industry, the residual dyes in the filtrate can be recovered to reduce emission pollution.
The plate and frame filter press takes high filtration accuracy, low filter cake moisture content, durable structure and easy maintenance as its core advantages. It is especially suitable for processing high viscosity, high solid content, fine particles or materials that need to be strictly intercepted. It is widely used in environmental protection, chemical industry, food, mining, pharmaceutical and other fields. Although it is a batch equipment, its advantages in separation effect and cost control make it still the preferred filtration equipment for many industrial scenarios.
