Segmented Sintered Elements for Hazardous Area Speakers

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Solution Overview

Problem

Conventional sintered elements used in hazardous area speakers face challenges in effectively arresting flames while maintaining sound pressure levels, due to limitations in pore size and manufacturing yield, leading to compromised sound output and high production costs.

Innovation Solution

The development of sintered elements with varying flame paths and pore sizes, fabricated using thermally conductive materials and rapid prototyping techniques, allowing for increased sound transmission and improved flame arrest capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the pore size of the sinter is increased to allow sound to pass through, then sound pressure level is improved, but the flame arrest capability deteriorates

Engineering Contradiction:

Improvesound pressure levelVSAvoidflame arrest capability

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The sinter is segmented into multiple pores of different sizes rather than using a uniform pore structure. This segmentation allows the sinter to have both small pores for flame arrest and larger pores for sound transmission, resolving the contradiction between sound pressure level and flame arrest capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the sinter have different pore sizes tailored to local requirements. The sinter structure is non-uniform with varying pore dimensions distributed throughout, allowing optimal local performance for both flame suppression and acoustic transmission

Inventive Principle:

Principle #3Local quality

2Reliability

If the sinter material is made more thermally conductive to improve flame arrest, then flame suppression capability is improved, but the temperature rise of the sinter increases

Engineering Contradiction:

Improveflame suppression capabilityVSAvoidsinter temperature

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The thermal conductivity parameter of the sinter material is optimized to achieve the right balance. By carefully selecting and adjusting the thermal conductivity parameter, the sinter can absorb enough heat to suppress flames while limiting its own temperature rise to prevent self-ignition

Inventive Principle:

Principle #35Parameter changes

3Reliability

If conventional sinter manufacturing processes are used to control maximum pore size, then flame arrest requirement is met, but manufacturing yield decreases

Engineering Contradiction:

Improveflame arrest requirementVSAvoidmanufacturing yield

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The manufacturing approach changes from strictly controlling maximum pore size to controlling the distribution of pore sizes. This parameter change in the quality control strategy allows more variability in individual pores while maintaining overall flame arrest performance, thereby increasing manufacturing yield

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The sinter is treated as a composite structure with multiple pore types rather than a uniform material. This composite approach allows the aggregate structure to meet flame arrest requirements even if individual pores vary in size, improving manufacturing yield

Inventive Principle:

Principle #40Composite materials

4Reliability

If the mean pore size is reduced to improve flame arrest, then flame suppression is improved, but sound pressure level decreases

Engineering Contradiction:

Improveflame suppressionVSAvoidsound pressure level

Core Design Contradiction:

ReliabilityVSIllumination intensity

Solution Approach 1:

The pore structure is segmented into different size categories rather than using a uniform mean pore size. This segmentation allows the sinter to have a distribution of pore sizes where smaller pores handle flame suppression and larger pores contribute to sound transmission, resolving the contradiction

Inventive Principle:

Principle #1Segmentation

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 design enhances sound pressure levels and increases the yield of usable sintered elements, balancing flame suppression and acoustic efficiency while reducing production costs.

Implementation Method 1

The sinter's ability to extinguish combustion results from the transfer of heat energy, or enthalpy, from the flame to the solid matrix of channels within the sinter. The rate of heat transfer depends on the temperature gradient between the flame and the sinter, the channel hydraulic diameter, and the thermal conduction (diffusivity) properties of the gas.

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

The sinter should allow sound created by the driver to pass out of the enclosure and into the re-entrant horn to be amplified

Methodology Applied

Scientific EffectAcoustic wave transmission: Sound

Data Source

PatentUS7938223B2Sintered elements and associated systems

Publication Date: 2011.05.10 EATON INTELLIGENT POWER LTD

AI summary

Sintered elements for use in hazardous areas comprise a first flame path having a first length and a first pore size, and a second flame path having a second length and a second pore size. The second length is greater than the first length and the second pore size is greater than the first pore size. Sounders and loud speakers for use in hazardous areas comprise a housing having a horn and a rear enclosure, a driver assembly, and a sintered element.