Hand-held Spreader Impeller Gap Design for Jam Prevention
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Solution Overview
Problem
Conventional hand-held spreaders often jam due to particulate material lodging under the impeller, obstructing rotation and potentially damaging the spreader, and they require frequent cleaning to maintain performance.
Innovation Solution
A hand-held spreader design featuring a rotating impeller with a circular platform and vanes, where the outer periphery extends over the chamber's bottom edge to create a small gap that prevents larger particles from entering under the impeller, allowing smaller particles to exit harmlessly through a bottom aperture, and includes a self-cleaning mechanism with a movable gate and flow rate control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the impeller is mounted in a chamber with a discharge opening, then particulate material can be discharged away from the user, but particulate material can lodge under the impeller and obstruct rotation
Solution Approach 1:
The chamber bottom is segmented into two functional zones: an aperture region for discharging processed particulate material and an overflow region for removing unprocessed material. This segmentation allows the system to handle different material states separately, preventing jams while maintaining discharge functionality.
Solution Approach 2:
The overflow region acts as an intermediary mechanism between the chamber and the exterior. Instead of allowing material to directly accumulate under the impeller, the overflow region provides an intermediate path for excess material to exit, preventing obstruction of the impeller rotation.
2Productivity
If the impeller rotates to discharge particulate material, then distribution is achieved, but particulate material builds up in the chamber under the impeller requiring periodic cleaning
Solution Approach 1:
The chamber is designed with an integrated overflow region that automatically removes unprocessed particulate material as it accumulates. This self-service mechanism continuously maintains the chamber without requiring external intervention or periodic cleaning, eliminating time loss while preserving distribution productivity.
Solution Approach 2:
The overflow region provides preliminary removal of excess particulate material before it can build up to problematic levels. By continuously draining material in advance, the system prevents the need for periodic cleaning operations, maintaining continuous productivity.
3Productivity
If the impeller is positioned close to the chamber bottom for efficient discharge, then material distribution improves, but particulate material can easily enter under the impeller and cause jamming
Solution Approach 1:
The chamber bottom is divided into distinct functional zones: an aperture area for efficient material discharge directly beneath the impeller and an surrounding overflow region for material removal. This segmentation allows the impeller to operate close to the bottom for efficiency while the overflow zone prevents jamming by removing excess material.
Solution Approach 2:
The overflow region serves as an intermediary safety mechanism that prevents direct contact between excess particulate material and the impeller. Even when the impeller is positioned close to the chamber bottom, the overflow region intercepts and removes material that could otherwise cause jamming.
Data Source
AI summary
A hand-held spreader is provided having a housing with a compartment for particulate material, a chamber below the compartment having a bottom wall with a circular aperture, an impeller mounted for rotation in the chamber along such bottom wall responsive to a hand crank, a discharge opening, and a path along which the particulate material passes into the chamber for discharge via the discharge opening. The impeller has an outer circular periphery proximal to and extending over an outer edge of the aperture to form a gap between the impeller and the bottom wall of the chamber that seals the gap from the particulate material larger than the gap from entering under the impeller and risking obstruction of impeller rotation. Any particulate material that enters the gap passes downward through the aperture to enable self-cleaning of particulate material that would otherwise collect under the impeller in the chamber.