Clothes dryer and method of controlling the same

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Solution Overview

Problem

Existing clothes dryers face challenges in accurately determining the amount of laundry, leading to inefficiencies in drying time and potential damage to clothing due to inconsistent rotation speeds and slip between the drum and belt, which affects drying performance and convenience.

Innovation Solution

A method that involves a controller to sense current values during acceleration and maintaining stages of drum rotation, adjusting the rotation speed according to a set acceleration gradient to accurately measure the laundry load and optimize drying operations, minimizing errors and enhancing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the drum rotation speed is increased to improve drying speed, then the drying efficiency is improved, but slip between the drum and belt occurs leading to inaccurate laundry amount measurement

Engineering Contradiction:
Improvedrying speedVSAvoidlaundry amount measurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by implementing a two-stage rotation speed control: an acceleration stage with controlled gradient to prevent slip during load sensing, and a maintaining stage with higher speed for efficient drying. This dynamic speed adjustment resolves the contradiction between measurement accuracy and drying speed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent performs preliminary action by conducting laundry amount measurement during the acceleration stage before entering the maintaining stage. This ensures accurate load detection is completed before high-speed drying begins, preventing slip-related measurement errors while maintaining drying efficiency.

Inventive Principle:
Principle #10Preliminary action

2Loss of time

If the acceleration gradient is increased to reduce sensing time, then the productivity is improved, but the slip between drum and belt increases reducing measurement accuracy

Engineering Contradiction:
Improvelaundry amount sensing timeVSAvoidlaundry amount measurement accuracy
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The patent optimizes the acceleration gradient dynamically to balance sensing time and measurement accuracy. By controlling the acceleration gradient within an appropriate range, the system achieves sufficient sensing speed while preventing slip between drum and belt, resolving the time-accuracy trade-off.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the drying time is extended to ensure complete drying, then the drying thoroughness is improved, but user convenience deteriorates due to operation not terminating at preset time

Engineering Contradiction:
Improvedrying completion qualityVSAvoiduser convenience
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent implements feedback by using the accurately measured laundry amount to dynamically adjust and terminate the drying operation. The controller monitors drying progress based on initial load measurement and ends the operation when drying is complete, ensuring both thorough drying and timely termination for user convenience.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary measurement of laundry amount before drying to enable accurate drying time calculation. This preliminary action allows the system to predict when drying will be complete and terminate at the appropriate time, avoiding both under-drying and excessive operation time.

Inventive Principle:
Principle #10Preliminary action

4Productivity

If the temperature is increased to accelerate drying, then the drying speed is improved, but laundry damage occurs

Engineering Contradiction:
Improvedrying speedVSAvoidlaundry damage from heat
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by adjusting operation parameters based on measured laundry amount. The system optimizes temperature and time combinations dynamically, using higher temperatures for shorter periods or lower temperatures for longer periods depending on load size, achieving efficient drying while preventing heat damage.

Inventive Principle:
Principle #15Dynamics

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 precise determination of the laundry amount, improving drying efficiency, preventing over- or under-drying, and ensuring the drying operation is completed within a preset time, enhancing user convenience and product reliability.

Implementation Method 1

a motor having double shafts, to which the drum and the blow fan are connected, respectively

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

a heat pump module for heating up the air which circulates while passing through the drum by rotation of the drum and by movement of the blow fan, through thermal exchange with a refrigerant

Methodology Applied
Scientific EffectThermal exchange: Heat Exchanger

Implementation Method 3

an evaporator through which the air, which has circulated while passing through the drum, passes, to condense moisture contained in the air

Methodology Applied
Scientific EffectPhase change: Phase Change

Data Source

PatentEP3492648B1Clothes dryer and method of controlling the same
Publication Date: 2021.06.09 LG ELECTRONICS INC
  • EP3492648B1 patent drawingFigure 1
  • EP3492648B1 patent drawingFigure 2~3
  • EP3492648B1 patent drawingFigure 4~5

AI summary

Disclosed are a dryer (1) and a method of controlling the same, the dryer (1) which is capable of: quickly and accurately determining an amount of laundry (9) loaded in the dryer (1) and controlling a drying operation (S340) according to the amount of the laundry (9): measuring a current supplied to rotate the drum (30) and extracting a force applied to laundry (9) in the drum (30) to measure an amount of the laundry, thereby minimizing an error in the amount of laundry and thus enhancing accuracy of the measurement and improving a drying time; setting a drying time in consideration of both a calculated amount of laundry (9) and a type of the laundry (9), such that damage to the laundry is prevented and over-drying or less-drying of the laundry is solved, thereby efficiently drying the laundry.