Dishwasher Constrained Layer Damping to Reduce Spray Impact Noise
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Solution Overview
Problem
Contemporary dishwashers generate significant noise due to the mechanical operation of pumps and sprayers, as well as the impact of recirculated liquid on the tub and door, which is not adequately attenuated by existing sound-dampening materials like mastic, failing to meet high-end sound level standards of 38 dB(A).
Innovation Solution
The integration of constrained layer damping (CLD) material, in combination with a mastic layer, is applied to specific zones within the dishwasher, such as the side walls, door, and bottom wall, to effectively reduce sound transmission and vibration, enhancing sound attenuation beyond what mastic alone can achieve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If mastic material is used for sound attenuation, then sound absorption is provided, but the sound level remains above 38 dB(A) and high-end sound standards are not met
Solution Approach 1:
The patent applies a composite sound attenuation system combining multiple materials with different properties: constrained layer damping (CLD) material for vibration control, mastic material for sound absorption, and foam material for additional damping. This multi-material composite approach achieves the required 38 dB(A) sound level by leveraging the complementary strengths of each material type rather than relying on a single material solution.
Solution Approach 2:
The patent implements zone-specific sound attenuation by identifying spray impact zones and rainfall zones within the dishwasher tub, and applying different densities and types of sound attenuation materials to different zones. High-density materials are placed in high-impact areas while lower-density materials are used in other areas, optimizing sound attenuation efficiency and achieving the 38 dB(A) target.
2Object-affected harmful factors
If sound attenuation materials are added to the dishwasher, then noise reduction is achieved, but device complexity increases
Solution Approach 1:
The patent integrates sound attenuation materials directly into the tub structure and existing components during manufacturing. The CLD material is applied to the tub wall, mastic material is incorporated into the tub assembly, and foam material is integrated with structural elements. This merging approach achieves noise reduction without adding separate, complex sound attenuation systems.
Solution Approach 2:
The constrained layer damping material serves as an intermediary between the tub structure and the sound environment, converting structural vibrations into heat through viscoelastic deformation. This intermediary mechanism effectively reduces noise transmission without requiring complex active noise control systems or additional mechanical components.
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 use of CLD material in conjunction with mastic significantly reduces noise levels, achieving an overall sound level of 38 dB(A) or less, thereby meeting high-end dishwasher sound standards and providing a more quiet operation.
Implementation Method 1
a constrained layer damping (CLD) material and a mastic layer located on at least one of the first spray impact zone, second spray impact zone, third spray impact zone and the rainfall zone
Implementation Method 2
The use of CLD material in conjunction with mastic significantly reduces noise levels, achieving an overall sound level of 38 dB(A) or less
Data Source
AI summary
A dishwasher having a treating chamber with one or more sprayers through which liquid is recirculated into the treating chamber, whereby the impact of the spray emitted from the sprayers impacts the structure forming the treating chamber to generate noise. Damping material is applied to structure forming the treating chamber to reduce the sound level of the impact exterior of the dishwasher.