Marine Exhaust Flapper Relocation for Noise Reduction
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Solution Overview
Problem
Existing marine exhaust systems face issues with excessive heat causing damage to elastomeric seals in flappers, leading to metal-to-metal contact, noise generation, and wear, particularly when cooling fluid levels are reduced.
Innovation Solution
Repositioning the flapper upstream in a water-cooled exhaust system to contact an elastomeric coupling device instead of the metallic exhaust tip or pipe, reducing noise and wear by avoiding direct metal-to-metal contact and utilizing an elastomeric material for the flapper tip to enhance sealing and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flapper is positioned downstream where cooling water flow mixes with exhaust gasses, then the flapper operates under normal conditions, but excessive heat from prolonged absence or reduction of cooling fluid damages the elastomeric seals causing metal-to-metal contact
Solution Approach 1:
An elastomeric coupling device is introduced as an intermediary component between the metallic exhaust tip and the exhaust pipe portion. This coupling device acts as a mediator that absorbs thermal expansion and movement, preventing direct contact between the flapper and metallic surfaces, thereby eliminating metal-to-metal contact even under high heat conditions.
Solution Approach 2:
The elastomeric coupling device is installed in advance to provide cushioning protection. This pre-positioned elastomeric material serves as a buffer that absorbs thermal stress and mechanical movement before they can cause damage to the flapper or exhaust components, preventing metal-to-metal contact before it occurs.
2Ease of operation
If the flapper is positioned downstream in the exhaust system, then it functions as designed, but direct metal-to-metal contact results in excessive noise generation during engine operation
Solution Approach 1:
The elastomeric coupling device serves as an intermediary that absorbs and dampens mechanical impacts and vibrations. By positioning this elastomeric material between the metallic exhaust components, it reduces the transmission of noise-generating vibrations while maintaining the flapper's operational functionality.
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 new flapper configuration effectively reduces noise and wear by preventing metal-to-metal contact and maintaining low noise levels even under high heat conditions, while allowing for elastomeric material durability and noise reduction capabilities.
Implementation Method 1
an elastomeric coupling device coupling such exhaust tip to such exhaust pipe portion
Implementation Method 2
water cooled marine exhaust systems
Data Source
AI summary
Disclosed are apparatus and methodology for reducing noise and wear in a flapper configured exhaust tip for a marine exhaust system. A flapper, normally located within an exhaust tip of a marine exhaust system, is relocated upstream of the point in the exhaust system where cooling water normally contacts the exhaust pipe. An exhaust tip is coupled to the upstream portion of the exhaust system by way of an elastomeric coupling device. The flapper is positioned such that a tip thereof contacts the elastomeric coupling rather than the metallic exhaust pipe. Such contact with an elastomeric coupling device reduces noise previously produced by flapper contact with the hot exhaust pipe occasioned by destruction and/or heat degeneration of elastomeric material generally associated with the flapper device.