Separating Device Using Cross-Flow and Falling-Stream Screening
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Solution Overview
Problem
Existing separation processes, such as air classification, fail to effectively separate lightweight, dispersible portions containing organic matter from heavier materials, leading to mixed residues during the treatment of material mixtures, particularly in biowaste composting.
Innovation Solution
A separating device that combines falling-stream screening with cross-flow screening, utilizing a flow channel with a slope and a cross-flow device to separate materials based on density, where an air stream is used to extract lightweight portions and a baffle element separates heavier materials, allowing for effective separation of lightweight, organic matter-containing materials from other fractions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If air classification process is used to separate lightweight portions from heavy objects, then lightweight material can be separated, but organic matter-containing material and other material remain mixed together
Solution Approach 1:
The separation process is divided into two distinct stages: first, a falling-stream screen separates lightweight dispersible portions (including organic matter) from heavy objects; second, a cross-flow device separates the lightweight portions into organic matter-containing material and other material. This segmentation resolves the contradiction by achieving precise multi-level separation without requiring a single complex device.
Solution Approach 2:
The falling-stream screen acts as an intermediary device that first removes heavy objects from the mixture, creating a purified stream of lightweight material that can then be processed by the cross-flow device. This intermediate step enables the subsequent cross-flow separation to work more effectively on a pre-filtered stream, improving overall separation precision.
2Productivity
If screen rejects are produced for larger fraction, then grain size separation is achieved, but rejects still contain portions that need further separation
Solution Approach 1:
The screening process is segmented into primary screening (producing screen rejects) and secondary separation (processing rejects through cross-flow device). This allows high-volume primary separation to maintain productivity while the secondary stage ensures complete separation of remaining portions, resolving the contradiction between throughput and completeness.
Solution Approach 2:
The falling-stream screen performs preliminary separation by removing the bulk of heavy objects first, creating a concentrated stream of lightweight material. This preliminary action increases the efficiency of the subsequent cross-flow device, which then completes the separation with higher precision on a smaller, pre-concentrated stream.
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
The device achieves more efficient separation of lightweight and heavy materials by braking falling portions based on density and using a cross-flow to direct them into specific separation regions, enhancing the separation of organic matter-containing materials from other material streams.
Implementation Method 1
at least one conveying means, which conveys air through the flow channel
Implementation Method 2
an air stream, in particular containing a lightweight material, can exit the flow channel
Implementation Method 3
a cross-flow device, which is connected to the second end region of the flow channel in flow communication with the flow channel and has a separation chamber and an air intake, which leads into said chamber and through which the cross-flow device can introduce air into the separation chamber in a flow direction extending at an angle to the main longitudinal extension direction of the flow channel
Implementation Method 4
a separation apparatus formed in particular as a baffle element is arranged between the first and the second separation region
Data Source
AI summary
A separating device for separating different material fractions out of a feed-material mixture having a flow channel, which has a slope, extends in parallel with the direction of gravity in particular in its main longitudinal extension direction and comprises an inner chamber. The separating device has a first end region, a second end region, a material inlet region intended for feeding the feed-material mixture into the inner chamber of the flow channel, an outlet through which an air stream containing a lightweight material can exit the flow channel, at least one conveying means that conveys air through the flow channel, and a cross-flow device that has a separation chamber and an air intake that leads into said chamber and through which the cross-flow device can introduce air into the separation chamber in a flow direction extending at an angle to the main longitudinal extension direction of the flow channel.