A filter press is a pressure filtration device that separates liquids from solids using filter cloths and plates. Filter press filtration works by pumping slurry into chambers. Pressure then forces liquid through filter cloths, leaving behind dewatered solids (filter cake). Filter presses are used in wastewater treatment, mining, chemical processing, and many other industries.
Understanding Filter Press Filtration Technology
As sustainable water treatment becomes more important, filter press filtration delivers efficient results. Filter presses separate liquids from solids using pressure filtration. Because of this, they support many industries and treatment goals. Common uses include municipal water treatment, industrial wastewater management, food processing and pharmaceutical production.
When you understand filter press operation, you can reduce costs and also improve environmental compliance through reliable pressure filtration.
A filter press includes several core components. These include filter plates, filter cloths, a steel frame, hydraulics, and manifolds. Together, these parts drive consistent solid-liquid separation.
To get the best performance, extend equipment life and reduce downtime you must understand each component. In turn, that knowledge helps extend equipment life and reduce downtime.
Filter plates form the chambers where filtration takes place. Filter cloths are a critical component, as they act as the medium through which the filtrate passes while retaining the solids.
The hydraulic system is used to open and close the press, applying the necessary pressure during the filtration cycle. Multiple filter plates are clamped plates together within a steel frame.
This plate stack creates a circuit for the liquid, beginning and ending at the manifold.
How Does a Filter Press Work?
How does it work? During the fill cycle, the system pumps slurry into the filter press. Solids then distribute evenly throughout each chamber. This process effectively separates the liquid from the solids.
Filter Cloths and Plates
The filter cloth lies at the core of a filter press filtration system, separating liquid filtrate from suspended solid particles. Initially, fine particles may pass through (fig. 1). Subsequently, larger particles block the cloth’s openings and form a layer that improves filtration efficiency by narrowing the effective pore size (fig. 2). During the feed cycle, the press distributes solids evenly into each chamber. As pressure builds, they compact tightly, which enhances dewatering efficiency (fig. 3).
By the end of the filtration cycle, the filter press fills each chamber completely with dewatered filter cake. The system forms each chamber by clamping two filter plates together and enclosing the cavity in filter cloth. The steel frame holds and aligns the plates, creating a chamber system that defines the press’s total filtration capacity.
Manifold
After the liquid passes through the cloth barrier, the plates feature an inner porting system that delivers filtrate to the manifold. Once filling is complete, the operator adjusts the valves to end the cycle and to direct filtrate out through a single outlet.
When the filtration cycle ends, the follower retracts, and the operator can empty the press. The operator clamps the press to start a new batch.
Many high-capacity filter presses use fast-action automatic plate shifters to speed up cycle times. Manufacturers build some filter presses for fully automatic, 24-hour operation in harsh environments like mining and chemical processing.
Advantages of Using Filter Presses
Filter presses provide several advantages in water treatment applications.
- High levels of dewatering can be achieved which significantly reduces the volume of waste.
- By producing a dry filter cake, they lower the liquid content in waste streams, helping facilities cut disposal costs and reduce environmental impact.
- Operators can customize filtration precision by selecting the right filter cloths and adjusting operating conditions to meet specific requirements.
- Engineers design filter presses to handle abrasive slurries and perform reliably under harsh conditions.
- The reliable, durable, and modular design of filter presses makes them a versatile and efficient solution for filtration.
Types of Filter Presses
The most common types—plate and frame, recessed chamber, membrane, and automatic—each serve specific applications and operational needs by design.
- A plate and frame press uses alternating plates and frames clamped together to create a series of filtration chambers. Plate and frame presses work well in applications with low solids content and minimal filtration demands.
- Recessed chamber presses use recessed plates to form individual filtration chambers. In comparison, recessed chamber systems operate more efficiently and handle higher solids concentrations. For more info see differences between plate and frame and recessed chamber.
- Membrane presses incorporate flexible membranes within the plates to produce drier filter cakes and improve separation efficiency.
- Automatic presses support high-volume operations with minimal manual intervention.
Applications
Industries like surface finishing, chemical engineering, battery recycling, bioplastic production, mining, data centers, and food and beverage processing all integrate filter presses into their workflows.
Industry demands and application requirements guide filter press design decisions. Operating conditions further influence filtration capacity, chamber count, plate size, and material selection.
In addition, design options may include plate shifters, cloth washing system, drip trays, cake shields and safety light curtains. Because of these variables, engineers customize each filter press for the specific application.
Key design goals include filtration cycle time, desired cake dryness, and extended cloth life. Finally, automation preferences range from manual operation to fully automated plate shifting systems.
Why M.W. Watermark?
M.W. Watermark® manufactures industry-leading equipment for water and process filtration applications worldwide. Our team offers a wide selection of filter press types, capacities, parts, and accessories to suit different applications. Visit our Filter Presses product page to learn more. Use our custom designed filter press sizing calculator to find the right solution for your application.
Contact our team of experts to discuss your filtration needs.