Noise Abating Impeller with Asymmetric Blade Spacing
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Solution Overview
Problem
Regenerative blowers with 'paddle wheel' impellers generate high-pitched noise due to the continuous sound wave created by twin vortices, which existing designs fail to effectively mitigate.
Innovation Solution
A noise-abating impeller design featuring a disc-shaped central hub with radially extending blades arranged in symmetric groupings, where blades are spaced increasingly and decreasingly apart in alternating quadrants, and a dividing rib to break the continuity of the sound wave, reducing high-pitched noise by creating multiple smaller sound peaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a paddle wheel impeller design is used, then the blower can operate with simple structure and high reliability, but it generates high-pitched noise due to continuous sound wave from twin vortices
Solution Approach 1:
The impeller blades are divided into multiple segments or zones along their length, with each segment having different geometric parameters (such as angle, curvature, or spacing). This segmentation breaks the continuous sound wave generation into discrete segments, creating multiple smaller noise peaks instead of one continuous high-pitched tone, thereby reducing the overall noise perception while maintaining the reliable paddle wheel impeller structure
2Ease of manufacture
If blades are arranged with uniform spacing, then the impeller structure is simple and easy to manufacture, but it creates a continuous sound wave pattern that amplifies noise
Solution Approach 1:
The blade spacing or blade geometry is made asymmetric along the impeller circumference or blade length. Specifically, adjacent blades are positioned at non-uniform intervals, or blade parameters vary progressively along the blade span. This asymmetric arrangement disrupts the formation of continuous sound waves by creating irregular flow patterns and multiple scattered vortex shedding points, converting a single continuous noise peak into multiple smaller peaks across different frequencies
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 impeller design significantly reduces high-pitched noise by fragmenting the sound wave, lowering decibel levels, especially in the 6,000-8,000 Hertz range, and providing a more erratic noise pattern, thus reducing overall noise emission.
Implementation Method 1
The rotating impeller blades then use centrifugal force to impart motion to the air in order to accelerate the air radially outward and forward through the housing chamber
Implementation Method 2
A certain amount of air slips past the tip of each impeller blade and returns to the base of a succeeding blade for re-acceleration within the compression space. Regenerations of the air within the blower housing are repeated and each regeneration becomes another 'stage.' Each 'stage' imparts more pressure to the air and creates a vortex.
Data Source
AI summary
A noise abating impeller having a disc-shaped central hub and a plurality of blades extending radially outward from the central hub. The blades are symmetrically arranged in quadrants around the central hub and within two alternating quadrants, each blade is spaced an increasing distance apart from a prior adjacent blade and within the other two alternating quadrants, each blade is spaced a decreasing distance apart from a prior adjacent blade. The impeller also has a dividing rib located along the entire outer peripheral edge of the central hub and located along the center of the blades dividing each blade into a first blade half and a second blade half. The first blade half is offset from the second blade half.