Impeller Blade Offset Geometry for Regenerative Pump Efficiency

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Solution Overview

Problem

Existing impellers in side channel compressors and vacuum pumps face inefficiencies in fluid compression due to suboptimal design of blade edges and chamber geometry, which limits their operational efficiency and requires multiple stages for effective compression.

Innovation Solution

The impeller design features a largest offset dimension of 0.1 to 0.6 times the difference between the first and second radius dimensions, with the end edge following a radius line and the radius drawn from a circle center within a blade chamber, enhancing radial speed and pressure build-up by optimizing blade geometry and chamber configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If the end edge of the blade wall is designed with a larger offset dimension, then the pressure build-up is improved, but the radial speed increases which may cause fluid leakage and reduce compression efficiency

Engineering Contradiction:
Improvepressure build-upVSAvoidradial speed
Core Design Contradiction:
Stress or pressureVSSpeed

Solution Approach 1:

The patent applies parameter changes by precisely defining the offset dimension as a specific proportion (0.1 to 0.6 times) of the difference between the first and second radius dimensions. This quantitative parameter optimization resolves the contradiction by finding the optimal balance point where pressure build-up is sufficiently improved while radial speed remains controlled, preventing fluid leakage and maintaining compression efficiency.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If multiple impeller stages are used to achieve effective compression, then the compression efficiency is improved, but the device complexity increases

Engineering Contradiction:
Improvecompression efficiencyVSAvoidnumber of impeller stages
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the compression function into two distinct operational phases within a single impeller: radial compression in the blade chambers and axial compression in the side channels. This functional segmentation allows one impeller to achieve compression capabilities traditionally requiring multiple stages, thereby reducing device complexity while maintaining high compression efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies multi-functionality by designing a single impeller that performs multiple compression functions. The impeller simultaneously creates radial pressure build-up through optimized blade geometry and enables axial compression through the side channel configuration, making one component perform the work of multiple traditional stages.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If the end edge follows a curved path instead of a radius line, then the blade geometry is more complex which may improve fluid flow, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvefluid flow efficiencyVSAvoidend edge geometry precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies inversion by reversing the conventional approach: instead of designing a complex curved end edge to achieve radial velocity optimization, the patent uses a simplified radius line configuration. The beneficial fluid flow effects are then achieved through the optimized offset dimension and the interaction between the blade and side channel geometry, thereby reducing manufacturing precision requirements while maintaining flow efficiency.

Inventive Principle:
Principle #13The other way round (Inversion)

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 improves pressure build-up and allows for a two-stage operation with a single impeller, increasing radial speed and operational efficiency compared to previous solutions.

Implementation Method 1

Within the blade chambers, the fluid is forced outwards by centrifugal force and compressed.

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

As the impeller rotates, the fluid flows through the inlet into the side channel and is carried along by the impeller blades. This so-called circulation is repeated several times, so that the fluid can be compressed in several stages until it reaches the outlet.

Methodology Applied
Scientific EffectCentrifugal compression: Centrifugal Force

Data Source

PatentEP3140548B1Impeller for regenerative pump
Publication Date: 2023.05.03 GEBR BECKER GMBH
  • EP3140548B1 patent drawingFigure 1~2
  • EP3140548B1 patent drawingFigure 3
  • EP3140548B1 patent drawingFigure 4

AI summary

The invention relates to an impeller (1), in particular for a side channel machine, having blades (5) which are arranged distributed in the circumferential direction, are formed in each case by a blade wall (6) and form open blade chambers (4) in a plan view of the impeller (1), wherein a blade wall (6) begins, in plan view, at a first radius dimension (r1) in relation to the geometric impeller rotational axis (x), which radius dimension (r2) corresponds to half or more of a second radius dimension (r2), which radius dimension (r2) defines a circumferential edge (9) of the impeller (1), and wherein the radius dimension (r2) defines a radially inner boundary wall (7) of the blade chamber (4), wherein, furthermore, a blade wall (6) has an exposed upper termination edge which correspondingly runs radially on the inside into the inner boundary wall (7) and ends radially on the outside in plan view, wherein an imaginary connecting line (V) can be drawn between a run-in point of the termination edge into the inner boundary wall (7) and a radially outer end of the termination edge (12), and the termination edge runs perpendicularly with respect to the connecting line (V) with a different offset dimension, wherein a greatest offset dimension is given. For advantageous development, in particular with regard to an improved degree of efficiency, it is proposed that the greatest offset dimension corresponds to 0.1 times or more the difference of the second (r2) and the first radius dimension (r1).