Lightweight Polymer Muffler Using Porous Foam Attenuator
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Solution Overview
Problem
Current environmental control system ducting in mass transit vehicles is heavy, expensive, and labor-intensive to manufacture, with existing mufflers failing to provide adequate noise attenuation while meeting safety and weight distribution requirements, and they have high flammability, toxicity, and smoke generation concerns.
Innovation Solution
A lightweight muffler using a flexible, thin-walled thermoplastic cover tube with an open cell polymer foam attenuator tube, such as SOLIMIDE or melamine foam, secured by end fittings, which provides effective sound attenuation and meets stringent safety criteria.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional wet winding process with fiberglass batting and steel wire is used, then noise attenuation is achieved, but weight and manufacturing complexity increase
Solution Approach 1:
The patent uses porous polymer foam material as the acoustic absorber instead of traditional fiberglass batting. The foam's cellular structure provides effective noise attenuation while being inherently lightweight, eliminating the need for heavy steel wire reinforcement and complex wet winding processes.
Solution Approach 2:
The patent employs composite construction using polymer foam combined with thermoplastic coating materials. This composite approach achieves both acoustic performance and structural integrity without requiring heavy metal components, reducing overall muffler weight while maintaining durability.
2Object-affected harmful factors
If traditional wet winding process with skilled labor is used, then acoustic absorber assembly is achieved, but manufacturing time and cost increase
Solution Approach 1:
The patent divides the muffler into separate modular components: the polymer foam acoustic absorber, thermoplastic coating layers, and end caps. These segmented components can be manufactured independently and assembled through simple processes, eliminating the need for continuous wet winding operations requiring skilled labor.
Solution Approach 2:
The patent replaces expensive, labor-intensive wet winding processes with simpler, more economical manufacturing methods using readily available polymer materials that can be processed through automated extrusion and molding techniques, significantly reducing manufacturing costs and time.
3Strength
If coated fabrics and adhesives are used in closure caps, then structural integrity is achieved, but manufacturing complexity and labor requirements increase
Solution Approach 1:
The patent replaces complex multi-layer coated fabric constructions with simpler thermoplastic materials that can be molded into ready-to-use end caps. These caps provide sufficient structural integrity through their molded design alone, eliminating the need for multiple coating layers and adhesive applications.
4Object-affected harmful factors
If traditional materials are used, then noise attenuation is achieved, but flammability and smoke generation concerns increase
Solution Approach 1:
The patent uses porous polymer foam materials that are inherently more fire-resistant than traditional organic-based acoustic absorbers. The foam structure can be formulated with fire-retardant properties, reducing flammability and smoke generation while maintaining effective noise attenuation performance.
Solution Approach 2:
The patent employs composite material systems combining polymer foam with thermoplastic coatings that provide both acoustic performance and enhanced fire safety characteristics. This composite construction achieves noise attenuation while meeting stringent flammability and smoke generation standards.
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 solution significantly reduces weight and manufacturing costs, while offering superior noise reduction and improved safety characteristics, such as low flammability and toxicity, making it suitable for large aircraft applications.
Implementation Method 1
flexible foam or foams having a density selected and arranged for optimal attenuation across a spectrum of sound frequencies or noise
Data Source
AI summary
An environmental control system muffler including a thin wall polyetherether ketone (PEEK) cover tube, an open cell polymer attenuator tube slip fit there into and polymer end fitting securing the two tubes together and cooperating to form a pneumatic seal with the cover tube. The method of making the muffler apparatus includes the selection of tubing constructed of such PEEK corrugated construction and the open cell polymer noise attenuation construction, telescoping the tubes together and securing the end fittings thereto.