Overlapping Sieve Arrangement for Grain Cleaning
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Solution Overview
Problem
Conventional grain-cleaning machines using granulometric separation by sieves have reduced sieving capacity due to the presence of curtains, limiting their processing rate and efficiency.
Innovation Solution
The machine features a sieve arrangement with overlapping main sieve levels, each comprising a fine sieve followed by a grain sieve, allowing residues smaller and larger than grains to be separated efficiently, with surplus grains being reprocessed at a lower sieve level, eliminating the need for curtains and enhancing sieving capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If curtains are installed on main sieve levels to contain bouncing grains, then grain retention is improved, but sieving capacity is reduced
Solution Approach 1:
The main sieve level is segmented into two functional zones: a first zone with open grain sieves for active sieving, and a second zone with closed grain sieves for containment. This segmentation allows different portions of the sieve to perform different functions, resolving the contradiction between retention and capacity by containing grains in the second zone while maintaining sieving efficiency in the first zone.
Solution Approach 2:
A transition structure connects the first open grain sieve to the second closed grain sieve, serving as an intermediary that guides grains from the active sieving zone to the containment zone. This transition structure acts as a mediator that maintains grain flow and retention without blocking the sieving action in the first zone.
2Productivity
If processing rate is increased to handle more mixture per hour, then productivity is improved, but equipment size must increase
Solution Approach 1:
The sieve arrangement utilizes vertical stacking of multiple sieve levels (first main sieve level, second main sieve level, and lower sieve level) to increase processing capacity. By adding the vertical dimension, the system can process more material simultaneously without increasing the horizontal footprint, as each level processes a portion of the feed stream in parallel.
Solution Approach 2:
Multiple sieve levels are nested vertically within the housing, with the first main sieve level positioned above the second main sieve level, and the lower sieve level positioned below. This nested arrangement maximizes the use of vertical space, allowing high processing rates within a compact equipment footprint by effectively stacking processing stages.
3Productivity
If grain sieves operate at full capacity without curtains, then sieving efficiency is improved, but grain retention is worsened
Solution Approach 1:
The grain sieve system is divided into a first grain sieve with open structure for high-capacity sieving and a second grain sieve with closed structure for grain retention. This segmentation allows the first sieve to operate at full capacity without retention concerns, while the second sieve provides the necessary containment for grains that need to be retained.
Solution Approach 2:
The transition structure ensures continuous grain flow from the first open grain sieve to the second closed grain sieve, maintaining uninterrupted sieving action. This continuity allows grains to be progressively processed through both zones, achieving both high sieving efficiency and adequate retention without interrupting the useful action.
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
This configuration increases the processing rate of grains and residues, achieving higher tons per hour without occupying more physical space, as the grain sieves operate at full capacity, improving overall efficiency.
Implementation Method 1
a vibration system configured to oscillate the sieve arrangement
Implementation Method 2
Due to the inclination of each main sieve level and due to the oscillating movement of the sieve arrangement produced by the vibration system, each mixing layer moves toward the low side of the respective main sieve level
Data Source
AI summary
A grain-cleaning machine for obtaining grains has a desired size which is greater than a lower value and less than or equal to an upper value. The grain-cleaning machine comprises an arrangement of sieves. The arrangement of sieves comprises at least two main sieve levels positioned overlapping each other. Each main sieve level comprises a respective fine sieve followed by a respective grain sieve. At least one lower sieve level comprises a respective lower grain sieve. The at least one lower sieve level being positioned below the main sieve levels. Each fine sieve has a first mesh provided with openings having an opening size which is equal to said lower value, and each grain sieve and each lower grain sieve have a second mesh provided with openings having an opening size which is equal to said upper value.