Dishwasher Centrifugal Pump Air Bubble Removal

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Solution Overview

Problem

Centrifugal pumps in household appliances often suffer from air bubbles being trapped and forming a swirling hose, which negatively affects pump performance.

Innovation Solution

The integration of helically arranged flow guide vanes that extend close to or reach the underside of the impeller, promoting the removal of air-bubbled fluid by creating a gradient that directs it away from the pump bottom and towards the outlet, with the vanes being stationary or removable and designed to be self-supporting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional pump design is used, then pump structure is simple, but air bubbles form swirling hose and pump performance deteriorates

Engineering Contradiction:
Improvepump performanceVSAvoidpump structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pump chamber is segmented by introducing flow guide vanes that divide the circulating fluid into different flow paths. These vanes create distinct regions for water flow and air bubble removal, preventing the formation of a unified swirling hose while maintaining overall pump functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Flow guide vanes are introduced as intermediary elements between the impeller and pump chamber walls. These vanes mediate the interaction between circulating fluid and air bubbles, directing water flow while allowing air bubbles to be tapped off and removed through specific pathways without disrupting the main pumping action.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If flow guide vanes are added to remove air bubbles, then ventilation effect improves, but device complexity increases

Engineering Contradiction:
Improveventilation effectVSAvoidnumber of flow guide vanes
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of uniformly distributing flow guide vanes throughout the pump chamber, the invention applies them locally at specific positions where air bubble accumulation occurs. The vanes are strategically placed to tap off circulating fluid and air bubbles at critical points, providing effective ventilation with minimal structural addition.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The flow guide vanes are designed to extend partially to the underside of the impeller or close to it (maximum distance of 5mm, particularly advantageously 3mm or even only 1mm). This partial extension is sufficient to create the necessary gradient for air bubble removal without requiring the vanes to reach the full extent that would maximize structural complexity.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If flow guide vanes extend close to impeller underside, then air bubble removal improves, but risk of disturbing radial outflow increases

Engineering Contradiction:
Improveair bubble removalVSAvoiddisturbance to radial outflow
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The flow guide vanes are designed with asymmetric geometry, running helically away from the pump bottom with a pitch in the direction of impeller rotation. This asymmetric helical configuration allows the vanes to effectively tap off air bubbles while their orientation and pitch angle are optimized to minimize interference with the radial outflow of water from the impeller.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The flow guide vanes are designed with curved, helical surfaces that follow the rotational direction of the impeller. This curvature allows the vanes to smoothly guide air bubbles away from the pump bottom while maintaining compatibility with the rotational flow pattern, reducing turbulence and disturbance to the main water outflow.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

Effectively removes air bubbles and improves fluid flow without significantly impacting water pumping efficiency, enhancing the pump's ventilation and delivery effects.

Implementation Method 1

the at least one flow guide vane... causes the circulating fluid and in particular the above-described circulating hose made of water with a large number of air bubbles in it to be tapped off on the underside of the impeller at the bottom of the pump and due to the gradient in the direction of rotation of the impeller is promoted away from the pump bottom and towards the outlet from the pump

Methodology Applied
Scientific EffectGravity: Gravitation

Implementation Method 2

the centrifugal pump with the impeller sucks in fluid or water to be conveyed centrally and in the axial direction and flows out again radially or conveys it out of the impeller

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2495444B1Pump
Publication Date: 2015.07.01 E G O ELEKTRO GERAETEBAU GMBH
  • EP2495444B1 patent drawingFigure 1
  • EP2495444B1 patent drawingFigure 2~3
  • EP2495444B1 patent drawingFigure 4~6

AI summary

A pump (11) for a dishwasher has an impeller (19) for conveying fluid, and is designed as a centrifugal pump with central axial suction (16) and radial discharge (18) of the fluid to be conveyed. The impeller extends along its underside above a pump base, with several stationary flow guide vanes (25a, 25b) arranged radially outside the impeller. These vanes are helically inclined with a pitch extending away from the pump base (15a) in the direction of rotation of the impeller (29). At least one flow guide vane (25a, 25b) extends to the underside of the impeller to capture a circulating tube of fluid containing air bubbles.