Rack and Bag System for Recycling Waste Sheet Material
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Solution Overview
Problem
Current recycling methods for thin-section plastic films are labor-intensive, lead to low bulk density, high transportation costs, and increased environmental impact due to the inclusion of air in the waste material, resulting in limited economic value and increased risk of worker injury from repetitive movements.
Innovation Solution
A specially designed rack and plastic bag system that allows air to escape during compaction, increasing the bulk density of baled materials by 10-25% and reducing manual labor through strategic hole placement and friction elements, facilitating easier handling and transportation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If waste plastic film is placed in a receptacle using conventional methods, then the material can be collected for recycling, but the bulk density remains very low due to large volume of air in the space occupied by the waste film
Solution Approach 1:
The bag is designed with air escape holes and is placed in a rack position before waste film is loaded. As waste film is added, the bag expands and air escapes through the holes, preliminarily removing air from the system before final compaction, thereby increasing bulk density without requiring additional compaction steps.
Solution Approach 2:
The bag incorporates an array of holes distributed about its circumference, creating a porous structure that allows air to escape during the loading and compaction process. This porous design enables continuous air removal while maintaining the bag's structural integrity and containing the waste material.
2Productivity
If waste plastic film is manually retrieved and placed in containers, then collection can be performed, but the process is labor intensive and workers are subject to repetitive movement injuries
Solution Approach 1:
The rack and bag system is designed to be self-loading. Workers simply place waste film onto the rack, and the bag automatically expands and compacts the material as it is loaded, eliminating the need for manual compaction and repetitive lifting movements. The system serves itself by using the weight of the waste film to compress the bag and remove air.
Solution Approach 2:
The system divides the collection process into two independent functions: the rack provides structural support and positioning, while the bag provides containment and automatic compaction. This segmentation allows each component to perform its specific function efficiently, improving overall productivity while reducing physical demand on workers.
3Quantity of substance
If waste plastic film is compacted and baled, then bulk density increases, but air remains trapped within the compacted bulk mass, limiting the bulk density to substantially less than the mass density of the polymer
Solution Approach 1:
The bag with air escape holes provides continuous air removal throughout the loading process. As waste film is continuously added and the bag expands, air is continuously expelled through the holes, maintaining a progressively denser configuration. This continuous action ensures maximum air removal before the bag is sealed and transported.
Solution Approach 2:
Instead of attempting to remove air from the top or bottom of the compacted mass, the holes are distributed around the entire circumference of the bag, allowing air to escape from all radial directions simultaneously. This multi-dimensional air removal approach ensures complete air expulsion from the compacted material.
4Productivity
If conventional recycling methods are used, then waste plastic film can be processed, but transportation costs increase due to high volume and low bulk density
Solution Approach 1:
The bag is prepared with air escape holes and positioned on the rack before waste film is loaded. This preliminary configuration ensures that air is removed during the loading process itself, so the material is already compacted and dense before transportation. The preliminary air removal action eliminates the need for additional compaction equipment during transport.
Solution Approach 2:
The system changes the physical state of the waste film from a loose, low-density configuration to a compacted, high-density configuration through the bag's expansion and air escape mechanism. This parameter change in density occurs automatically during loading, transforming the material's transportation characteristics without requiring external intervention.
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 the economic value of recycled materials by increasing bulk density, reduces transportation costs, and minimizes worker injuries by reducing the physical demands of handling and loading processes.
Implementation Method 1
an array of holes being distributed about the circumference of the bag, and extending along at least sixty percent of the length of the bag, the holes being located and sized so as to provide a hole open area, in the hole array, about the circumference and along the length of the bag, effective to facilitate escape of air from the bag during compression of the bag
Implementation Method 2
at least one of a friction element or a point restrictor being mounted on the rack at a location where a weight in the bottom of the bag applies a stress in the bag at the top of the rack
Data Source
AI summary
Specially-designed rack and plastic bag, and methods of use. The bag is mounted on the rack with a lower portion of the bag disposed inwardly and downwardly of the top of the rack, and an upper portion of the bag disposed outwardly and downwardly of the top of the rack. Workers place thin-section waste material into the bag. When the bag is full, the bag is replaced with an empty bag. The bag has holes, which enable air to escape through bag side walls while the bag is being compressed in a baler. Because air escapes through the side walls, more of the air can be removed for a given baler compaction force thereby the resulting bale weighs about 10% to about 25%, or greater, more than a bale made with the same materials and the same baler conditions, without use of the rack and bags of the invention.