Disc filters are high-efficiency, energy-saving solid-liquid separation devices widely used in mining, metallurgy, chemical, environmental protection, and food industries, especially suitable for dewatering fine-particle materials. Powered by vacuum or pressure, they achieve continuous automated operation through the filter media on the discs, offering advantages such as compact structure, stable operation, and easy maintenance.
Working Principle
The core principle of a disc filter is to use a pressure difference (vacuum or positive pressure) to drive liquid through the filter cloth, while solid particles are trapped on the filter cloth surface to form a filter cake.
- In vacuum-type equipment, the filter disc is partially immersed in the slurry tank. The vacuum system creates a negative pressure inside the filter disc (typically around 0.08 MPa). Under the pressure difference, the liquid passes through the filter cloth into the filter chamber, while solids adhere to the filter cloth surface to form a filter cake.
- As the filter disc rotates, the filter cake sequentially passes through the filtration zone, drying zone, unloading zone, and washing zone, completing one cycle:
- Filtration zone: Adsorbs slurry and forms a filter cake;
- Drying zone: Continues to apply vacuum to reduce the moisture content of the filter cake;
- Unloading zone: Removes the filter cake using back-blowing air or a scraper;
- Washing zone: Automatically washes the filter cloth to restore permeability.
- Some newer equipment also employs a "self-stirring" design, using the rotating filter disc to impact the slurry for uniform distribution and to prevent sedimentation.
Product Structure
A disc filter press mainly consists of the following parts:
- Tank: Contains the slurry and has an inlet and overflow weir.
- Main Shaft and Filter Disc Assembly:
- Multiple fan-shaped filter plates are assembled into a circular filter disc, typically made of high-strength engineering plastics or stainless steel.
- The filter plates are covered with nylon monofilament or multifilament filter cloth, which is corrosion-resistant and not easily clogged.
- Vacuum System: Includes a vacuum pump, distribution valve, and filtrate piping, used to establish and control a negative pressure environment.
- Distribution Valve: Controls the switching of air paths in different areas of each filter chamber, ensuring orderly process operation.
- Unloading Device: Uses back-blowing, scraper, or vibration to remove the filter cake.
- Filter Cloth Cleaning System: High-pressure water nozzles automatically rinse the filter cloth to maintain filtration efficiency.
- Transmission System: A motor and reducer drive the main shaft to rotate at low speed (commonly 0.5–3 rpm), supporting frequency conversion speed regulation to adapt to different material concentrations.
- Automated Control System: PLC controls operating parameters (such as speed, vacuum, backflushing pressure) to achieve unattended operation.
Product Advantages
- High efficiency and energy saving: Compared with traditional filtration equipment, energy consumption is reduced by more than 30%, and the footprint is reduced by more than 50% for the same processing capacity.
- High degree of automation: The entire process is controlled by PLC; operators only need to monitor the operating status, reducing labor intensity.
- Low filter cake moisture content: After further dehydration in the drying zone, the filter cake moisture content can be reduced to below 16% (e.g., zinc concentrate processing).
- Long filter cloth life: Using wear-resistant nylon filter cloth and an automatic cleaning device, the service life is increased by more than 40%.
- Modular design: The number of filter discs can be flexibly increased or decreased according to the processing volume, facilitating capacity expansion and maintenance.
- Good sealing performance: Using mold positioning welding technology, leakage points are reduced by 90%, improving vacuum stability.
- Wide range of applications: Can process a variety of materials such as metallic ores, non-metallic ores, coal slime, chemical crystals, and sludge.
