Laundry device and method for operating the same

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Solution Overview

Problem

Existing laundry care devices face inaccuracies in determining final residual moisture, leading to inefficient energy use due to reliance on sensor accuracy, which degrades over time, causing premature or late termination of the drying process.

Innovation Solution

A laundry care appliance with a detection unit comprising humidity, temperature, and air pressure sensors that continuously monitor the drying process, calculating a switch-off value based on relative humidity changes rather than absolute values, ensuring consistent moisture determination independent of sensor accuracy and drift.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If absolute humidity measurement is used to determine drying completion, then the drying process can be controlled, but measurement accuracy degrades over sensor lifespan leading to unreliable termination decisions

Engineering Contradiction:
Improveresidual moisture measurement accuracyVSAvoidsensor reliability over lifespan
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the measurement parameter from absolute humidity to relative humidity combined with temperature. This allows derivation of water load through calculation rather than direct measurement, bypassing sensor drift issues. The control unit calculates water load based on relative humidity and temperature measurements, which remain stable throughout the sensor's operational life.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces temperature as an intermediary parameter. Instead of relying solely on humidity sensors, the system uses temperature measurements in combination with relative humidity to calculate water load. This intermediary approach compensates for sensor inaccuracies and maintains measurement reliability over time.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If sensor-based absolute humidity measurement is used, then drying control is achieved, but energy efficiency decreases due to premature or late termination

Engineering Contradiction:
Improvedrying process efficiencyVSAvoidenergy waste from inaccurate termination
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent implements a feedback mechanism where the control unit continuously monitors relative humidity and temperature, calculates water load, and compares it against target values. This closed-loop feedback ensures precise determination of drying completion, preventing both premature termination (which would leave laundry too moist) and late termination (which would waste energy).

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary calculations to determine the water load early in the drying process and establishes a target water load value. By having this reference point established in advance, the system can accurately determine when drying is complete, optimizing energy usage without requiring extended drying cycles.

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 method allows for precise control of the drying process, improving energy efficiency by ensuring accurate determination of dryness levels throughout the appliance's service life, preventing early or late termination of the drying cycle.

Implementation Method 1

a humidity sensor (10) designed to determine the relative humidity of the process air

Methodology Applied
Scientific EffectRelative humidity measurement: Hygrometer

Implementation Method 2

a temperature sensor (10) designed to determine the temperature of the process air

Methodology Applied
Scientific EffectTemperature sensing: Thermocouple

Implementation Method 3

a dehumidification unit (14) for condensing water from the process air

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP3346049B1Laundry device and method for operating the same
Publication Date: 2019.11.13 BSH HAUSGERATE GMBH
  • EP3346049B1 patent drawingFigure 1
  • EP3346049B1 patent drawingFigure 2
  • EP3346049B1 patent drawingFigure 3

AI summary

A laundry care appliance (2) with a drying function has an air circuit (17), a control unit (12) and a detection unit (10) which has a humidity sensor for determining the relative humidity (34) of the process air and a temperature sensor. The detection unit (10) measures the temperature and the relative humidity (34) during a drying process and transmits them to the control unit (12). The control unit (12) determines a water load (28) in the air circuit (17) of the laundry care appliance (2) from the transmitted measured values, analyzes the course of the water load (28) during the drying process and uses this to determine a switch-off value (30) which indicates the end of the triggers the drying process.