Dishwasher

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Solution Overview

Problem

Prior dishwashers face inaccuracies in turbidity measurements due to turbulence and varying conditions, leading to inappropriate washing cycle selections, resulting in excessive energy or detergent consumption or inadequate cleaning.

Innovation Solution

A dishwasher with a variable speed centrifugal pump and a turbidity sensor that adopts standardized operating reference conditions to minimize turbulence and ensure accurate turbidity measurements, using a combination of flow control and geometry adjustments in the ducting system to stabilize the washing liquid before measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the dishwasher measures turbidity during normal washing operation, then the measurement reflects actual washing conditions, but the turbulence distorts the measurement accuracy

Engineering Contradiction:
Improveturbidity measurement accuracyVSAvoidturbulence distortion
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by stopping the pump before taking turbidity measurements. This ensures that the washing liquid is stationary and free from turbulence at the measurement location, eliminating distortion effects. The pump is activated again after measurement to resume normal washing operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts the measurement function from the continuous washing process by creating a separate, dedicated measurement phase. During this phase, the pump is stopped and measurements are taken in isolation from the turbulent washing operation, ensuring measurement accuracy without interfering with the overall washing function.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If the dishwasher selects more vigorous washing cycles based on high turbidity, then cleaning effectiveness improves, but energy and detergent consumption increase

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements feedback by continuously monitoring turbidity levels and using this information to dynamically adjust washing cycle parameters. The system measures turbidity, compares it against thresholds, and automatically selects appropriate washing intensities, ensuring energy-efficient operation while maintaining effective cleaning when needed.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies parameter changes by adjusting washing cycle parameters (duration, temperature, detergent dosage, pump speed) based on measured turbidity levels. Low turbidity triggers gentle cycles with reduced parameters, while high turbidity triggers vigorous cycles with increased parameters, optimizing the balance between cleaning effectiveness and resource consumption.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If the dishwasher uses a stationary turbidity sensor in the washing compartment, then the measurement location is fixed and simple, but the sensor may be affected by varying flow conditions

Engineering Contradiction:
Improvesensor positioning simplicityVSAvoidturbidity measurement consistency
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by stopping the pump flow before taking measurements at the stationary sensor location. This creates consistent, turbulence-free conditions at the fixed sensor position, ensuring measurement precision without requiring complex sensor positioning or flow control mechanisms.

Inventive Principle:
Principle #10Preliminary action

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 approach allows for reliable and repeatable turbidity measurements, enabling the dishwasher to select appropriate washing cycles based on actual dirtiness, optimizing energy use and cleaning effectiveness.

Implementation Method 1

a turbidity sensor located along the ducting means for detecting the dirtiness of the washing liquid passing the sensor

Methodology Applied
Scientific EffectTurbidity measurement: Absorption (EM radiation)

Implementation Method 2

a motor-driven pump 4. The motor-driven pump 4 is preferably a variable speed pump... In particular, the pump 4 is of the centrifugal type

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2201885B2Dishwasher
Publication Date: 2020.07.08 WHIRLPOOL EMEA SPA
  • EP2201885B2 patent drawingFigure 1

AI summary

A dishwasher comprises: - a washing compartment (2) designed to accommodate the articles to be washed; - spraying means (3) for spraying a washing liquid in the washing compartment (2); - a motor-driven pump (4); - ducting means (5) for connecting the washing compartment (2) and the spraying means (3), said pump (4) being located along the ducting means (5) in order to pump the washing liquid from the washing compartment (2) to the spraying means (3); - means (6) for measuring at least one physical property of the washing liquid, comprising a sensor (60) located in the washing compartment (2) or along the ducting means (5) and designed to detect the dirtiness of the washing liquid at the sensor (60). At least during each reading performed by the sensor (60) for measuring the dirtiness of the washing liquid, the dishwasher (1) adopting a first operating reference condition in which the flow processed by the pump (4) substantially always adopts the same predetermined value. [Figure 1]