Screw Extruder Feed Hopper with Inclined Arms Against Bridging
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Solution Overview
Problem
Existing feed hoppers for screw extruders fail to effectively handle biodegradable materials with fibrous fillers, leading to bridging, irregular material intake, process instability, and varying output speeds, particularly during the extrusion process.
Innovation Solution
A feed hopper with a mixer featuring triangular cross-section mixing arms inclined at 10-30° and a downward-facing brush at the outlet, preventing bridging by lifting material and ensuring consistent intake.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional feed hoppers are used for biodegradable materials with fibrous fillers, then the structure remains simple, but bridging occurs causing irregular material intake and process instability
Solution Approach 1:
The mixer is positioned in the feed hopper to perform preliminary mixing of the material before it reaches the extruder. The mixing arms with inclined rake surfaces agitate the material in advance, preventing bridging from occurring in the first place, thereby ensuring reliable and consistent material flow to the extruder.
Solution Approach 2:
The mixer acts as an intermediary device between the feed hopper and the extruder. It mediates the material flow by breaking up bridges and redistributing the material, ensuring that the extruder receives a steady, uniform supply of material regardless of bridging tendencies in the hopper.
2Ease of operation
If mixing arms with horizontal surfaces are used, then the structure is simple, but material bridging occurs and blocks gravitational flow to the screw
Solution Approach 1:
The mixing arms feature an asymmetric design with inclined rake surfaces at specific angles (10-30 degrees) rather than symmetric horizontal surfaces. This asymmetry creates effective lifting and sliding actions that break bridges and promote material flow, while the lower surface remains relatively flat to prevent excessive kneading.
Solution Approach 2:
The inclination angle of the rake surface is optimized within the range of 10-30 degrees. This parameter change transforms the mixing arm from a simple horizontal blade into an effective bridge-breaking tool that utilizes gravity and material weight to lift and redistribute particles, ensuring reliable flow to the screw.
3Reliability
If the outlet port is left open, then the structure is simple, but material bridges block the outlet causing irregular intake by the screw
Solution Approach 1:
The brush positioned at the outlet port acts as an intermediary element that prevents bridge formation at the critical discharge point. The bristles agitate and break up material bridges that form near the outlet, ensuring that the screw receives a consistent supply of material without interruptions caused by blocking.
4Reliability
If mixing arms with steep inclination angles are used, then bridging is prevented effectively, but excessive kneading of material occurs in the feed container
Solution Approach 1:
The mixing arm is designed with different surface qualities in different zones: the rake surface has a steep inclination (10-30 degrees) for effective bridge breaking, while the lower surface is relatively flat (inclined at most 3 degrees) to minimize kneading. This local differentiation of surface characteristics allows the arm to perform multiple functions without causing material degradation.
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
Prevents bridging and ensures stable material intake, maintaining consistent extrudate output speed and improving material quality with fibrous fillers.
Implementation Method 1
the weight of the material inside the feed hopper is lifted upwards, preventing it from 'bridging'
Implementation Method 2
the brush makes it possible to ensure that the outlet port is unobstructed
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The feed hopper is, according to the invention, characterised in that the mixing arms (4) have a triangular cross-section and have a rake surface inclined with respect to the horizontal plane by an angle from the range of from 10° to 30°, and further, the shaft (2) of the mixer is terminated from below with a brush (5) whose bristles are directed downwards and are arranged in the outlet port (6) of the feed container (1), wherein the bristle tips of the brush (5) protrude from this outlet port (6).