Variable Radius Discoid Filter Element for Sludge Filtration
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Solution Overview
Problem
Existing filtration apparatuses face reduced filtration efficiency due to increasing filter cake thickness, especially with high solids content suspensions, and require inefficient methods like pressure increase or shearing to maintain throughput, which are not effective for all cases.
Innovation Solution
The apparatus features a discoid filter element with a compression section that increases radius from a low-pressure to a high-pressure radius and an expansion section that decreases radius back, creating a sinusoidal pressure curve to enhance filtration and facilitate filter cake detachment through centrifugal forces and turbulence, allowing for continuous and efficient filtration regardless of solids content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If the filter element rotates to enable filter cake cleaning, then the filter cake can be removed from the filter membrane, but the relative movement is not sufficient for cleaning the filter cake in the case of high solids content suspensions and strongly pressed filter cakes
Solution Approach 1:
The filter element is designed with a variable radius that changes during rotation, creating dynamic compression and expansion sections. This dynamic geometry generates varying centrifugal forces that enhance filter cake detachment effectiveness, particularly for high solids content suspensions where static cleaning methods fail.
Solution Approach 2:
The radius of the filter element is changed as a variable parameter during rotation. The radius increases in the compression section and decreases in the expansion section, creating parameter changes that result in varying pressure and centrifugal forces to improve filter cake removal efficiency.
2Volume of stationary object
If the radius of the filter element increases in the circumferential direction to reduce the free housing cross-section, then the housing space is optimized, but the pressure distribution becomes uneven affecting filtration consistency
Solution Approach 1:
The filter element employs an asymmetric variable radius design where the radius changes in the circumferential direction. This asymmetric geometry creates distinct compression and expansion sections that generate controlled pressure variations, optimizing both housing space utilization and pressure distribution for consistent filtration.
3Productivity
If pressure on the suspension side is increased to maintain constant filtration rate, then the filtration rate is maintained, but the filter cake becomes more compacted making it harder to clean
Solution Approach 1:
The rotating filter element with variable radius creates periodic compression and expansion cycles. During the compression section, high pressure maintains filtration rate, while during the expansion section, pressure decreases to facilitate filter cake loosening and removal, creating a periodic action that addresses both filtration productivity and cleaning ease.
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 maintains high filtration throughput by promoting rapid filtration and effective filter cake detachment, reducing energy requirements and enabling efficient handling of suspensions with high solids content without the need for frequent cleaning interruptions.
Implementation Method 1
the suspension in the area of the filter element that is set in rotation is subjected to a pressure curve that changes over time, preferably sinusoidally
Implementation Method 2
the centrifugal forces caused by the rotary motion of the hollow shaft can be used to support detachment of the filter cake
Implementation Method 3
If a suspension flows against the filter element, the solid particles of the suspension are retained by the filter membrane, whereas a liquid portion of the suspension flows via the inner chamber of the filter element
Data Source
AI summary
Anapparatus for continuously filtering a sludge suspension, having a hollow shaft (2) that is rotatably mounted in a housing (1) and which that is fluidically connected to an inner chamber (6), which is surrounded by a filter membrane (5), of a discoid filter element (3) that radially protrudes from the hollow shaft (2), for removing a filtrate. A higher throughput of the filtrate, independently of the solids content of the sludge suspension to be filtered, is provided by the filter cake thickness and the filtration duration. The the radius (r) of the filter element (3) increases in the circumferential direction from a low pressure radius ri to a high pressure radius rh,reducing the free housing cross section.An apparatus for continuously filtering a sludge suspension, having a hollow shaft (2) that is rotatably mounted in a housing (1) and that is fluidically connected to an inner chamber (6), which is surrounded by a filter membrane (5) of a discoid filter element (3) that radially protrudes from the hollow shaft (2), for removing a filtrate. A higher throughput of the filtrate, independently of the solids content of the sludge suspension to be filtered, is provided by the filter cake thickness and the filtration duration. The radius (r) of the filter element (3) increases in the circumferential direction from a low pressure radius ri to a high pressure radius rh, reducing the free housing cross section.