Filter Press Cover Plate Bevel Design for Membrane Stress
Solution Overview
Problem
In filter presses, the inlet opening design leads to membrane overstretching and cake compaction during the pressing phase, causing blockages and uneven filling, resulting in differential pressures and potential plate fractures.
Innovation Solution
A cover plate with beveled openings is arranged around the inlet opening to distribute pressure evenly and prevent membrane overstretching, while additional slopes allow for hydraulic movement of sludge, ensuring the suspension remains free-flowing and preventing clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the inlet opening is made large to quickly fill the filter chamber, then the filling speed is improved, but the membrane is overstretched and strong local material stress occurs on the membrane
Solution Approach 1:
A cover plate is introduced as an intermediary component between the inlet opening and the membrane. The cover plate distributes the suspension flow and prevents direct high-pressure contact with the membrane, thereby maintaining fast filling speed while reducing membrane stress and preventing overstretching.
Solution Approach 2:
The cover plate is specifically positioned at the inlet opening area where the problem occurs, providing localized protection to the membrane. This allows the rest of the membrane to maintain its original function while the protected area experiences reduced stress during the filling phase.
2Productivity
If the inlet opening is made large to quickly fill the filter chamber, then the filling speed is improved, but cake compaction occurs in the inlet area during membrane pressing
Solution Approach 1:
The cover plate acts as a mediator that prevents direct compression of the cake in the inlet area by the membrane during the pressing phase. By distributing the pressure and creating a transition zone, the cover plate allows the inlet opening to remain large for fast filling while preventing harmful cake compaction during pressing.
3Quantity of substance
If the chamber filter element has a free inlet cross-section, then the suspension flow is improved, but the sludge becomes compacted and difficult to remove in the inlet area
Solution Approach 1:
The cover plate is designed with a beveled (sloped) surface instead of a sharp edge. This curved/angled geometry allows compacted sludge to slide off more easily during removal, preventing clogging while maintaining the free inlet cross-section for good suspension flow during operation.
4Ease of operation
If the cover plate is bevelled to allow sludge to slide out, then the sludge discharge is improved, but the membrane could be damaged by sharp edges
Solution Approach 1:
The beveled design provides a smooth, angled surface that serves dual purposes: it allows compacted sludge to slide off easily during removal while the gradual transition prevents sharp edges that could damage the membrane during operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design minimizes cake compression, maintains hydraulic flow, and prevents membrane damage, ensuring consistent chamber filling and extended membrane service life with reduced downtimes.
Implementation Method 1
a plate body provided with a bevel on both sides for deflecting the suspension into the filter chamber
Implementation Method 2
an overpressure is usually applied between the support plate and the membrane, which arches the membrane into the filter chamber and thus presses it onto the filter cake. This removes residual moisture from the filter cake.
Implementation Method 3
additional slopes (so-called draft angles) can advantageously be provided, which allow the cake to slide out of the vertical channel into the chamber in a directed manner
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The chamber filter element has multiple filter elements and two membrane filter elements with an intermediate chamber filter element joined together at the edges. A free inlet cross-section (8) of an inlet opening (2) is provided into the filter chambers.