Variable Pitch Auger Air Removal and Slippage Prevention
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Solution Overview
Problem
Existing machines for extruding semi-solid materials, such as mixed plastics and food products, face inefficiencies due to slippage and air pocket issues during the transition from coarse to fine pitch augers, leading to reduced throughput and portioning accuracy.
Innovation Solution
A multi-stage auger system with a conical hopper and drive motor that simultaneously turns the agitator and feed screw auger, featuring a helical entrainment screw with variable pitches to remove air and voids, and a die and cutter assembly capable of using both cutting wire and blade for different material types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a two-step pitch change from coarse to fine auger is used, then air and void removal is improved, but material slippage and slowdown occur at the transition point
Solution Approach 1:
The auger implements different pitch characteristics in different sections: a first section with coarse pitch for air removal, a transition section with intermediate pitch to bridge the gap, and a second section with fine pitch for precision dosing. This local differentiation allows each section to perform its specific function while the transition section prevents slippage and maintains continuous material flow.
2Productivity
If a coarse pitch auger is used for high throughput, then material flow rate increases, but air pockets and voids remain in the material
Solution Approach 1:
The auger is segmented into multiple functional sections along its length. The first section has coarse pitch optimized for high throughput and initial material conveyance. The transition section has intermediate pitch that gradually reduces to prevent slippage while continuing material flow. The second section has fine pitch for precise dosing and complete air pocket elimination. This segmentation allows the system to achieve both high throughput and reliable air removal.
3Manufacturing precision
If a fine pitch auger is used for precision dosing, then portioning accuracy improves, but throughput and material flow rate decrease
Solution Approach 1:
The auger system divides the conveying function across multiple sections with different pitch characteristics. The fine pitch second section ensures precise portioning accuracy, while the coarse pitch first section and intermediate pitch transition section maintain high throughput capability. This segmentation allows the fine pitch section to focus on precision without being bottlenecked by throughput limitations.
4Reliability
If separate coarse and fine pitch augers are coupled together, then air removal is achieved, but slippage occurs at the interface between augers
Solution Approach 1:
Instead of using two separate coupled augers, the invention merges the functionality into a single auger with a continuous variable pitch design. The transition section provides a gradual pitch change that eliminates the abrupt interface between separate augers, preventing material slippage and maintaining continuous flow. This unified design achieves air removal while ensuring operational smoothness.
5Device complexity
If a single pitch auger is used, then device complexity is reduced, but both air removal and precision dosing cannot be achieved simultaneously
Solution Approach 1:
The single auger implements local quality variations through different pitch sections along its length. The first section has coarse pitch for air removal, the transition section has intermediate pitch for smooth material transfer, and the second section has fine pitch for precision dosing. This local differentiation within a single auger achieves multiple functions without requiring multiple separate augers, balancing complexity with performance.
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 system enhances throughput by preventing slippage and air pocket formation, improving material flow continuity and portioning accuracy while accommodating various material types through efficient air and void removal and precise cutting mechanisms.
Implementation Method 1
augers that contain a helical profile that contains the medium to be moved by acting similar to a nut and bolt where the auger acts as a bolt or round threaded rod and the medium acts as the nut that upon rotation of the threaded rod (or as in this case the auger) the medium will move forward
Implementation Method 2
a fine pitch will carry less medium forward per revolution but do so with an ability to generate a higher pressure
Data Source
AI summary
A multi stage auger system having a hopper with a first diameter opening tapering to a second smaller diameter opening, coupled to an auger tube at the second smaller diameter opening. An auger entry spiral with generally helical shape and a sweep arm coupled thereto, the spiral and the sweep arm skimming inside the product hopper to entrain the semi-solid materials from the hopper wall and, through the shape of the spiral, moving materials through the hopper from the first opening towards the second smaller opening. During this entrainment and movement by the spiral and sweep arm a space is left between the spiral and the sweep arm to remove air and voids from the semi-solid material through the movement. The auger has a first coarse pitch providing further removal of air/void spaces and a second finer pitch providing further movement under higher pressures near an exit of the auger.