Injection-Molded Screen Assembly for Vibratory Screening Stability
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Solution Overview
Problem
Conventional metal and thermoset polymer screens for vibratory screening machines face issues such as structural instability, durability, blinding, high fabrication complexity, and limited configuration options, making them unsuitable for demanding applications.
Innovation Solution
The use of injection molded thermoplastic materials with multiple screen elements and subgrids to form a screen assembly that is structurally stable, customizable, and easy to assemble, featuring small screening openings and various configurations, eliminating the need for wire cloth and enhancing durability and recyclability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thermoset polymer screens are used for fine screening applications, then screening precision is improved, but fabrication complexity increases and manufacturing time is extended
Solution Approach 1:
The patent changes the material parameter from thermoset polymer to thermoplastic material, which fundamentally alters the fabrication process. Thermoplastics can be injection molded directly into fine screening patterns without requiring complex multi-step curing processes, chemical reactions, or precise temperature/pressure control during fabrication. This parameter change resolves the contradiction by maintaining fine screening precision while dramatically simplifying the fabrication process.
Solution Approach 2:
The patent replaces the chemical curing process inherent to thermoset polymers with a mechanical injection molding process using thermoplastics. Instead of relying on chemical reactions that require precise control of temperature, pressure, and curing time, the thermoplastic material is melted and injected into molds, then cooled and solidified through controlled thermal cycling. This substitution eliminates the complexity of chemical fabrication while preserving fine opening precision.
2Reliability
If metal screens are used for wet applications in the oil and gas industry, then durability is improved, but weight increases
Solution Approach 1:
The patent employs composite material construction by combining thermoplastic screening elements with a supportive substrate or frame structure. The thermoplastic material itself provides corrosion resistance and durability for wet applications, while the overall composite structure achieves the desired strength-to-weight ratio. This composite approach allows the screen to withstand harsh oil and gas environment conditions without requiring heavy metal construction.
Solution Approach 2:
The patent changes the material parameter from metal to thermoplastic, which fundamentally alters the weight and durability characteristics. Thermoplastics inherently provide corrosion resistance suitable for wet applications, eliminating the need for heavy metal construction. The material parameter change resolves the contradiction by maintaining durability through chemical resistance while significantly reducing weight compared to metal screens.
3Manufacturing precision
If conventional thermoset polymer screens are fabricated with fine openings, then screening precision is improved, but production time increases significantly
Solution Approach 1:
The patent replaces the slow chemical curing process of thermoset polymers with rapid injection molding of thermoplastics. The injection molding process involves melting the thermoplastic material, injecting it into precision molds containing the fine opening patterns, and cooling it to solidify. This mechanical/thermal process completes in minutes compared to the hours required for thermoset curing, thereby resolving the contradiction between precision and production speed.
Solution Approach 2:
The patent incorporates the fine opening patterns directly into the injection mold cavities before production begins. The molds are pre-manufactured with precise fine opening geometries, allowing the thermoplastic material to be injected and formed into the final screening pattern in a single step. This preliminary preparation of the molding tooling eliminates the need for post-fabrication processing or assembly, dramatically increasing productivity while maintaining precision.
4Stability of the object's composition
If a single large screen is molded as one piece, then structural stability is improved, but any flaw ruins the entire screen
Solution Approach 1:
The patent divides the screen into multiple smaller modular units or elements that can be independently manufactured and assembled. Each module contains a portion of the screening surface with fine openings, and modules are connected through joining mechanisms such as mechanical fasteners, adhesives, or interlocking features. This segmentation resolves the contradiction by maintaining overall structural stability through modular construction while allowing individual modules to be replaced if defects occur, thereby improving defect tolerance.
Data Source
AI summary
A disclosed screening apparatus includes a subgrid, and a screen element attached to the subgrid via laser welding at a plurality of attachment positions such that, under vibrational excitation, the screen element has a pre-determined profile of vibrational motion relative to the subgrid. The screen element may be attached at a maximal number of attachment locations to the subgrid to minimize relative motion of the screen element and the subgrid under vibrational excitation, or the screen element may be attached a sub-set of the maximal number of attachment locations to allow vibrational motion of the screen element relative to the subgrid. A disclosed method may include attaching a plurality of screen elements to a respective plurality of subgrids, attaching the plurality of subgrids to one another to form a screening pre-assembly, and cutting edges of the screening pre-assembly to form the screen assembly having a perimeter with a pre-determined shape.