Ventilator Impeller Blade Recess for Lower Rotational Stress

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Solution Overview

Problem

Existing impellers face increased mechanical stress with rotational speed, leading to higher material usage and energy consumption, without a viable solution to enhance strength without increasing weight or cost.

Innovation Solution

The impeller design features asymmetrical support sections and impeller blades with a recessed outer edge to reduce internal stresses, allowing higher rotational speeds without additional material or weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If greater wall thicknesses are used to increase strength in highly stressed areas, then the impeller can withstand higher mechanical stress, but the impeller becomes heavier and more expensive

Engineering Contradiction:
ImprovestrengthVSAvoidweight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent applies local quality by implementing a reinforcement element specifically in the highly stressed area where the impeller blade connects to the support section. This localized reinforcement increases strength precisely where needed without requiring increased wall thickness throughout the entire impeller, thereby avoiding the weight penalty associated with global thickening.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The reinforcement element creates an asymmetric structure in the impeller design. Rather than uniform wall thickness, the impeller has varying thickness with a concentrated reinforcement zone at the critical connection area. This asymmetric distribution of material optimizes strength-to-weight ratio by placing material only where structurally necessary.

Inventive Principle:
Principle #4Asymmetry

2Strength

If greater wall thicknesses are used to increase strength in highly stressed areas, then the impeller can withstand higher mechanical stress, but the manufacturing cost increases

Engineering Contradiction:
ImprovestrengthVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The reinforcement element provides localized strength enhancement only at the critical connection zone between the impeller blade and support section. This avoids the need to increase wall thickness across the entire impeller structure, reducing material consumption and manufacturing costs while maintaining sufficient strength where it is most needed.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent extracts the reinforcement function from the general impeller structure and implements it as a separate, dedicated reinforcement element. This modular approach allows for optimized material usage and simplified manufacturing, as the reinforcement can be designed and produced independently and then integrated only where required.

Inventive Principle:
Principle #2Taking out (Extraction)

3Strength

If the impeller is designed with increased material to withstand higher speeds, then mechanical strength increases, but energy consumption increases especially during acceleration

Engineering Contradiction:
ImprovestrengthVSAvoidenergy consumption
Core Design Contradiction:
StrengthVSUse of energy by moving object

Solution Approach 1:

The reinforcement element provides targeted strength enhancement only at the critical connection area, avoiding the need to increase material throughout the entire impeller. This localized approach reduces the overall mass of the impeller, thereby decreasing the energy required for acceleration while maintaining the strength necessary to withstand high operating speeds.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the structural parameter of the impeller by introducing a reinforcement element with specific geometric characteristics (extending in the radial direction with a height less than the blade height). This parameter modification optimizes the strength-to-mass ratio, enabling the impeller to withstand higher speeds with reduced material and lower energy consumption.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4700247A1Impeller for a ventilator
Publication Date: 2026.02.25 EBM PAPST MULFINGEN GMBH & CO KG
  • EP4700247A1 patent drawingFigure 1
  • EP4700247A1 patent drawingFigure 2~3
  • EP4700247A1 patent drawing

AI summary

The invention relates to an impeller (11) with two support parts (15, 16) and several impeller blades (17) arranged between the two support parts (15, 16) and connected to the first support part (15) by a first longitudinal edge (20) and to the second support part (16) by a second longitudinal edge (21). An outer edge (19) of each impeller blade (17) connects the two longitudinal edges (20, 21) and has an edge recess (25) at which the outer edge (19) has a local low point (P). The position of the low point (P) is closer to the support part (15, 16) in which higher internal stresses or loads occur during operation of the impeller (11).