Counter-Handed Auger Desegregation for HMA Uniformity
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Solution Overview
Problem
Existing methods for desegregating hot mix asphalt (HMA) fail to achieve uniform distribution of large and small particulate HMA, leading to segregation and temperature variations, which negatively impact roadbed durability.
Innovation Solution
A desegregation apparatus with a hopper and counter-handed auger assembly that laterally translates HMA streams, using configurable openings to mix and distribute HMA particles uniformly, ensuring a flatter profile upon delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If HMA is loaded into containers or dumped to create windrows, then HMA can be temporarily stored and transported, but segregation occurs with larger pieces rolling to the outside
Solution Approach 1:
The discharge system is segmented into multiple outlets arranged in a circular pattern, dividing the single discharge stream into multiple smaller streams. This segmentation prevents the formation of a single large pile where segregation can occur, and distributes material more uniformly across the storage area.
Solution Approach 2:
The discharge outlets are arranged in a circular pattern around the auger shaft, transitioning from a linear discharge approach to a two-dimensional circular distribution pattern. This dimensional change allows material to be deposited uniformly around the storage area, preventing concentration at any single location and reducing segregation.
2Device complexity
If conventional desegregation devices use single-stream discharge, then the structure is simple, but the HMA stream forms a pile causing re-segregation
Solution Approach 1:
The discharge system is segmented into multiple outlets arranged in a circular pattern, dividing the single discharge stream into multiple smaller streams. This segmentation prevents the formation of a single large pile where segregation can occur, and distributes material more uniformly across the storage area.
Solution Approach 2:
The discharge outlets are arranged in a circular pattern around the auger shaft, transitioning from a linear discharge approach to a two-dimensional circular distribution pattern. This dimensional change allows material to be deposited uniformly around the storage area, preventing concentration at any single location and reducing segregation.
3Adaptability or versatility
If HMA is transferred to MTV for temporary storage, then transportation flexibility is improved, but temperature variations develop due to faster cooling at the outside
Solution Approach 1:
The discharge system segments the HMA stream into multiple smaller streams discharged through outlets arranged in a circular pattern. This segmentation ensures that material is distributed uniformly throughout the storage area, with cooler exterior material mixing with warmer interior material, thereby reducing temperature gradients and maintaining more uniform temperature distribution during storage.
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 apparatus effectively remixes HMA, achieving a more uniform distribution of particle sizes and temperatures, resulting in improved roadbed durability and profile uniformity.
Implementation Method 1
The auger sections re-mix the HMA by laterally translating different portions of the HMA stream in opposing directions
Implementation Method 2
the auger sections re-mix the HMA by laterally translating different portions of the HMA stream in opposing directions and toward one of the open sections along the auger shaft
Data Source
AI summary
A desegregation apparatus that desegregates a stream of HMA that includes particles of varying size includes a desegregation hopper, which houses an auger assembly. A series of counter-handed augers is mounted on a shaft disposed within the hopper. Open sections are disposed between adjacent auger sections and above openings in the bottom surface of the hopper.