Centrifugal Pump Impeller Cutting Edges Prevent Clogging

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Solution Overview

Problem

Centrifugal pumps with vortex impellers face clogging issues due to fibrous or textile admixtures accumulating on the impeller, leading to blockages and potential pump failure, and existing comminution devices upstream of the impeller can negatively impact pump characteristics.

Innovation Solution

The blades of the impeller are designed with cutting edges formed at the contact points of the front and side surfaces, which are machined to create a cutting effect, and winglets with grooves or additional surfaces are used to enhance cutting and prevent accumulation, while maintaining efficient fluid flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a blade-free space is formed between the impeller and inlet-side housing wall to convey large solid admixtures, then the pump can handle larger particles, but fibrous or textile admixtures accumulate on the impeller center leading to clogging

Engineering Contradiction:

Improveability to convey large solid admixturesVSAvoidpump operation continuity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The cutting edges are positioned at the leading edge of the blades where solid admixtures first contact the impeller. This preliminary cutting action prevents fibrous materials from accumulating on the impeller center before they can be drawn into the blade-free space, thereby maintaining reliable continuous operation while preserving the ability to convey large particles

Inventive Principle:

Principle #10Preliminary action

2Reliability

If cutting edges are added to the blades to prevent accumulation, then clogging is avoided, but the impeller structure becomes more complex

Engineering Contradiction:

Improveresistance to cloggingVSAvoidimpeller structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Instead of modifying the entire blade structure, cutting edges are applied only at the specific location where solid admixtures first contact the impeller (the leading edge). This localized modification provides the necessary cutting function to prevent clogging while minimizing the increase in overall impeller structure complexity

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If conventional rounded blade surfaces are used, then the impeller is easier to manufacture, but cutting effect on fibrous admixtures is insufficient

Engineering Contradiction:

Improveimpeller manufacturingVSAvoidcutting efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The blade surfaces maintain conventional rounded geometry for ease of manufacture, but localized cutting edges are created at the leading edge through selective machining or hardening. This provides the necessary cutting efficiency against fibrous admixtures while preserving the overall ease of impeller manufacturing

Inventive Principle:

Principle #3Local quality

4Reliability

If upstream comminution devices are installed to shred fibrous components, then accumulation is prevented, but the pump characteristic curve is negatively influenced

Engineering Contradiction:

Improveprevention of accumulationVSAvoidpump system configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The cutting function is merged directly into the impeller blades by adding cutting edges to the blade leading edges. This integrates the comminution function into the existing pump structure, preventing accumulation of fibrous materials without requiring separate upstream comminution devices that would negatively affect the pump characteristic curve

Inventive Principle:

Principle #5Merging (Combining)

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 effectively prevents accumulation and clogging of solid admixtures, ensuring uninterrupted pump operation without compromising the pump's characteristic curve, as the cutting edges efficiently shred fibrous components and the winglets improve efficiency.

Implementation Method 1

the blades are provided with cutting edges, the cutting edges being formed at the contact lines where the front surfaces and the pressure-side side surfaces meet. The blades, which have cutting edges, cut through the solid admixtures

Methodology Applied

Scientific EffectMechanical cutting: Mechanical Force

Implementation Method 2

a centrifugal pump for pumping a medium mixed with solid admixtures, having a housing in which a free-flow impeller is arranged

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2226505B1Free flow impeller with cutting edges

Publication Date: 2013.11.27 KSB SE & CO KGAA

Figure 1
Figure 2a~2c
Figure 3a~3c

AI summary

The invention relates to a centrifugal pump for pumping a medium containing solids. A free-flow impeller (2) is arranged in the pump housing (1). A blade-free space (9) is formed between the free-flow impeller (2) and the inlet-side housing wall (8). Blades (7) are integrally formed on the support disc (6) of the free-flow impeller (2). The blades (7) comprise discharge-side side surfaces (13), suction-side side surfaces (11), and leading surfaces (12). According to the invention, the blades (7) are provided with cutting edges (14).