One Piece Blower Wheel Vibration Control

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Solution Overview

Problem

Impellers in gas-air premix fans experience negative impacts on noise behavior and air performance due to vibrational interactions with the driving rotor, particularly at the 8th order of the natural torsional frequency, leading to increased sound power and reduced efficiency.

Innovation Solution

A one-piece impeller design with a base disk and cover disk, where the ratio of the outer diameters is fixed between 0.69 and 0.74, reducing axial vibrations and noise emissions, and featuring a funnel-shaped cover disk with a constant material thickness, radially extending blades, and a non-overlapping disk configuration for improved manufacturability and reduced vibration excitation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the impeller is designed with a conventional structure, then the manufacturing is simple and economical, but the axial vibrations and noise emissions increase at the natural torsional frequency of the rotor

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidaxial vibrations and noise
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The invention changes the geometric parameters of the impeller, specifically the ratio of the outer diameter of the cover disk to the outer diameter of the base disk (dt/da), to optimize the natural frequencies and reduce vibrations. This parameter optimization allows the impeller to avoid resonant frequencies caused by the rotor, thereby reducing axial vibrations and noise while maintaining conventional manufacturing methods.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If the ratio of outer diameters dt/da is optimized to reduce vibrations, then the noise emissions decrease, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvenoise emissionsVSAvoiddimensional tolerance
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The invention specifies an optimized range for the ratio dt/da (between 0.69 and 0.74) that balances vibration reduction with manufacturing feasibility. This parameter range is carefully selected to achieve sufficient vibration mitigation while remaining compatible with standard manufacturing tolerances and processes, avoiding excessively stringent precision requirements.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3366929B1One piece blower wheel
Publication Date: 2020.05.13 EBM PAPST LANDSHUT GMBH
  • EP3366929B1 patent drawingFigure 1~2

AI summary

The invention relates to a blower wheel (1) in a one-piece design with a base disk (12) and a cover disk (11) between which a blade ring with several blower wheel blades (13) arranged circumferentially is formed, wherein the base disk (12) defines a radial maximum outer diameter da and the cover disk (11) forms an axial intake opening (25) with a diameter di, wherein the cover disk (11) extends radially outwards from the circumferential edge (14) forming the intake opening (25) and has a maximum outer diameter dt, and wherein a ratio of the outer diameters dt/da is defined in a range of 0.6 to 0.8.