Segmented Screw Geometry for Carbonizing Machine Venting
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Solution Overview
Problem
Current carbonizing machines face issues with particulate solids carryover and buildup in venting areas due to high gas velocity and abrupt transitions in screw geometry, leading to obstruction and reduced system throughput.
Innovation Solution
The design incorporates a screw with multiple sections, including helical advancing, standard helical, and reverse hand configurations, along with radially abutting paddles, to create smooth transitions and increase open volume, reducing solids carryover and enhancing system capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high gas velocity is used in venting areas, then volatile hydrocarbons can be effectively removed from organic material, but particulate solids are carried over and build up in vent openings causing obstruction
Solution Approach 1:
The screw is divided into multiple sections with distinct configurations (feed section, compression section, venting section, discharge section). Each section is optimized for its specific function, with the venting section designed to manage gas-solids separation. This segmentation allows high gas velocity for volatile removal in the venting section while preventing solids carryover through geometric design.
Solution Approach 2:
The screw geometry acts as an intermediary between the compression zone and venting zone. The specific screw configuration in the venting section mediates the interaction between gas and solids, allowing volatiles to escape while solids are retained and forwarded to the discharge section. The screw serves as a mechanical mediator that separates the functions of gas removal and solids transport.
2Productivity
If abrupt transitions in screw geometry are used, then compression and volatiles removal can be achieved, but material flow becomes disrupted causing solids to back up into vent areas
Solution Approach 1:
The screw geometry transitions dynamically from the compression section to the venting section through a carefully designed geometric progression. The pitch, flight depth, and channel geometry change gradually rather than abruptly, allowing material to adapt to changing conditions while maintaining continuous forward flow. This dynamic transition prevents material backup while preserving compression efficiency.
Solution Approach 2:
The screw design employs controlled parameter changes along its length, including pitch, flight depth, and channel cross-section. These parameters are optimized for each section: the compression section uses parameters that maximize densification, while the venting section uses parameters that facilitate gas escape. The gradual transition between these parameter sets maintains material flow continuity while achieving both compression and volatiles removal.
3Device complexity
If standard single-configuration screws are used, then device complexity is minimized, but system throughput capacity and venting efficiency are limited
Solution Approach 1:
The screw is segmented into multiple functional sections, each with optimized geometry for its specific task. This segmentation increases system throughput capacity by ensuring that each section performs its function efficiently, rather than a single configuration attempting to do everything. The feed section optimizes material intake, the compression section maximizes densification, and the venting section optimizes gas-solids separation.
Solution Approach 2:
Each section of the screw has local quality optimized for its specific function. The feed section has geometry suited for material intake and initial conveying, the compression section has geometry optimized for densification and heat generation, and the venting section has geometry optimized for gas escape and solids retention. This local optimization of quality in each section enhances overall system throughput while managing complexity through functional specialization.
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 configuration reduces particulate solids carryover into vents, increases system throughput, and prevents material buildup, ensuring efficient operation by directing only gas back into vent openings while forwarding solids.
Implementation Method 1
The intensive mixing subjects the organic material to frictional and viscous shear forces that create heat build up and particle attrition sufficient to change the phase of the particles and to convert their form.
Implementation Method 2
The intensive mixing subjects the organic material to frictional and viscous shear forces that create heat build up and particle attrition sufficient to change the phase of the particles and to convert their form.
Implementation Method 3
Municipal waste and other biomass may be converted to energy and useful products by a carbonizing process as disclosed, for example, in U.S. Pat. No. 5,017,269 to Loomans et al... Organic material is subjected to a sequence of mechanical compressions, intensive mixing, and decompressions in a continuous, twin screw reactor under adiabatic conditions.
Implementation Method 4
Organic material is subjected to a sequence of mechanical compressions, intensive mixing, and decompressions in a continuous, twin screw reactor under adiabatic conditions.
Data Source
AI summary
Screws for a carbonizing machine for carbonizing organic material into useful char product.