Short cycle times.
Dry filter cake.
Minimal energy consumption.
Economical filter press feeding requires a pump that automatically adapts to the filtration process. Emmerich’s piston-diaphragm pumps were developed precisely for this purpose.
During the filling phase, they initially deliver a high flow rate at low pressure. As the filter chambers fill, the back pressure increases while the flow rate automatically decreases. The standard mechanical control system adjusts the pressure and flow rate to the process—without additional sensors or external controls.
This shortens process cycles, reduces energy consumption, and promotes uniform dewatering with a dry filter cake.
When the filter press sets the pace
In sludge dewatering, the feed rate directly determines process stability and cycle time. The filter press must first be filled quickly and evenly. Afterward, the pressure rises while the flow rate decreases, and the pressing process transitions into a different operating phase.
For operators, therefore, it is not just the maximum pressure that matters. What is crucial is how consistently the pump operates throughout the entire cycle. An incorrectly sized pump can lead to long filling times, unnecessary energy consumption, increased wear, or uneven dewatering.
The appropriate feed pump is selected not only based on a single operating point, but also on the medium, flow rate, pressure profile, and press cycle.
Why Piston-Diaphragm Pumps Are Suitable for Filter Presses
Piston-diaphragm pumps are suitable for feeding filter presses when difficult-to-handle media must be conveyed in a controlled manner and high pressures must be reliably achieved. Thanks to the separation of the drive and the medium, the robust design, and the customized configuration, slurries, suspensions, and abrasive media can be reliably conveyed.
When feeding filter presses, it is particularly important that the pump not be considered in isolation. It must be compatible with the medium, the filter press, the piping, and the desired pressure range. While many pump systems require complex frequency control or external control for this purpose, pressure and flow rate adjustment in Emmerich’s piston-diaphragm pumps is performed mechanically and automatically as standard. For special requirements, a variable-frequency drive or a system-specific control system can be used as a supplement.
Requirements for the Loading Process
The feed rate to the filter press does not remain constant throughout the entire cycle. Therefore, the pump design should take the process sequence into account.
| Process Phase | Pump Requirements | Benefits for Operators |
|---|---|---|
| Filling Phase | High flow rate at low pressure | Rapid filling of the filter chambers |
| Pressure Build-up | Smooth transition to higher pressure ranges | Smooth transition to the pressing process |
| High-pressure operation | Controlled pumping against high back pressure | Uniform dewatering and improved process control |
| Control | Adjustment via frequency converter, mechanical control, or control system | Better adaptation to the medium, cycle, and system |
| Continuous operation | Robust design for recurring pressing cycles | Predictable operation and reduced risk of downtime |
The specific design depends on the medium, solids content, desired flow rate, pressure range, filter press type, and plant environment.
Pumped Fluids and Applications
When feeding a filter press, the media being conveyed often contain solids, are abrasive, or are chemically aggressive. The pump must not only move these media but also reliably control them throughout the entire pressing cycle.
Frequently Asked Questions About Filter Press Feeding
Pumps that deliver slurries or suspensions in a controlled manner and can reliably handle the transition from high flow rates to increasing pressure are suitable for feeding filter presses. Piston-diaphragm pumps are suitable for such applications when they are designed to match the medium, flow rate, pressure range, and filter press.
During the filling phase of the filter press, a large volume of medium is initially required at low pressure. As the press fills, the back pressure increases. The feed pump must adapt to this process so that the filling time, pressure buildup, and dewatering remain stable.
Yes, depending on the system, control via a variable-frequency drive (VFD) can be useful for better adapting the flow rate and pressure profile to the process. Whether VFD control, mechanical control, or another type of control is appropriate depends on the medium, the filter press, and the desired operating characteristics.
Typical media include slurries, suspensions, abrasive media, chemically contaminated liquids, and filter cake precursors. The solid content, particle size, viscosity, temperature, and chemical properties are critical factors in pump design.
To ensure a robust design, information is required regarding the pumped medium, solids content, flow rate, pressure range, filter press type, piping, operating time, and desired control system. Based on this information, the appropriate pump solution can be technically evaluated.
Yes, filter presses can also be used for sludge dewatering at wastewater treatment plants. If the focus is on municipal wastewater management, the page on pumps for wastewater treatment plants is also relevant.
