Stirred Hopper Spreader Assembly for Consistent Material Flow
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Solution Overview
Problem
Towed or mounted spreaders often exhibit inaccurate or inconsistent spread rates due to friction within the hopper and compression at the narrower funnel-like lower portion, leading to funnel flow and compromised structural integrity over time.
Innovation Solution
A mobile spreader assembly featuring a chassis, hopper, metering wheel, and stirrer, where the stirrer agitates materials within the hopper to promote mass flow, ensuring consistent material distribution and the metering wheel controls the spread rate by rotating beneath the hopper outlet, maintaining consistent flow and reducing friction effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a funnel-like lower portion is used in the hopper to direct materials to the outlet, then material flow direction is improved, but friction and compression cause inconsistent spread rates
Solution Approach 1:
A vibratory mechanism is incorporated into the hopper to induce vibrations that prevent material stagnation and reduce friction between material particles and the hopper walls. This vibration helps maintain consistent material flow rates by preventing the formation of stagnant zones and reducing the compressive forces that cause variable flow, thereby resolving the contradiction between the funnel shape's flow direction capability and the resulting spread rate inconsistency.
2Reliability
If vibration is applied to remediate material stagnation, then material flow is improved, but structural integrity is compromised over time
Solution Approach 1:
The vibratory mechanism operates at controlled amplitude and frequency parameters that are optimized to achieve effective material flow remediation while remaining below the thresholds that would cause structural damage. By carefully selecting and maintaining these operational parameters, the system achieves reliable material flow consistency without compromising the structural integrity of the hopper and associated components over time.
3Measurement precision
If the outlet size is reduced to control spread rate, then material distribution precision is improved, but funnel flow effects are exacerbated
Solution Approach 1:
The vibratory mechanism acts on the material before it reaches the outlet, pre-conditioning the flow to prevent stagnation and ensure uniform movement toward the outlet. This preliminary action on the material flow, taken upstream of the outlet, allows for precise spread rate control through outlet sizing without exacerbating funnel flow effects, as the vibration has already established consistent flow patterns that carry material uniformly to the restricted outlet.
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 assembly achieves a consistent and reliable spread rate of materials across the road surface, with the stirrer ensuring all materials exit at equivalent speeds, improving the metering wheel's filling consistency and reducing the risk of patchy distribution.
Implementation Method 1
The stirrer is configured to agitate the material within the hopper
Implementation Method 2
The materials are able to drop from the spreader through the outlet under the force of gravity
Data Source
AI summary
A mobile assembly for delivering materials to a road surface, the assembly comprising a chassis having a front and rear end, and one or more wheels supporting the chassis above the road surface intermediate said front and rear ends; a hopper mounted on the chassis having an inlet at an upper portion thereof for receiving the materials in the hopper, and an outlet at a lower portion of the hopper; and a metering wheel extending beneath the outlet for receiving the material therefrom, a speed of rotation of the metering wheel controllably delivering a volume of the materials to the road surface; wherein the assembly further comprises a stirrer located within the hopper and above the outlet and being configured to agitate the material within the hopper.