Tumble Dryer Tangling Detection Using Exhaust Air Temperature

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Solution Overview

Problem

Existing drying machines with rotating drums face inefficiencies due to clothes tangling, which leads to prolonged drying cycles and uneven dryness, as current methods for untangling clothes are often unnecessary and inefficient, and lack effective detection of tangling conditions.

Innovation Solution

A method that detects tangling conditions by monitoring temperature values of the drying air exiting the drum, comparing them to reference parameters, and initiating an untangling operation by modifying drum movements such as stopping or reversing rotation, ensuring efficient heat exchange and reducing energy waste.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If untangling procedures are launched at fixed time intervals, then clothes knots may be untied, but the cycle duration increases and drying efficiency decreases

Engineering Contradiction:

Improveknot preventionVSAvoiddrying efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system uses temperature sensors to continuously monitor the temperature of drying air exiting the drum and compares it against reference values. When the temperature deviates from expected ranges, indicating possible knot formation, the system triggers untangling procedures. This feedback mechanism ensures untangling is performed only when necessary, maintaining drying efficiency while preventing knots.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces fixed-time mechanical untangling schedules with a sensor-based thermal detection system. Instead of relying on timing mechanisms to trigger untangling at predetermined intervals, the system uses temperature monitoring to detect knot conditions and triggers untangling only when thermal anomalies indicate knot formation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If untangling procedures are launched at fixed time intervals, then clothes knots may be untied, but energy consumption increases

Engineering Contradiction:

Improveknot preventionVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system enables the drying process to self-regulate by automatically detecting knot conditions through temperature monitoring and triggering untangling procedures only when thermal anomalies indicate knot formation, eliminating the need for external scheduling or manual intervention.

Inventive Principle:

Principle #25Self-service

3Reliability

If the drum rotation is stopped or reversed for untangling, then clothes knots can be untied, but the load cools down and requires additional energy to warm up

Engineering Contradiction:

Improveknot preventionVSAvoidheat loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The system performs preliminary detection of knot conditions through temperature monitoring before untangling procedures are initiated. By detecting thermal anomalies that indicate knot formation, the system can trigger untangling at the optimal moment, minimizing the duration of rotation stoppage or reversal and reducing associated heat loss and energy consumption for re-warming the load.

Inventive Principle:

Principle #10Preliminary action

4Reliability

If untangling procedures are launched at fixed time intervals, then clothes knots may be untied, but motor wear increases due to frequent re-starting

Engineering Contradiction:

Improveknot preventionVSAvoidmotor wear

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

Inventive Principle:

Principle #23Feedback

5Reliability

If untangling procedures are launched at fixed time intervals, then clothes knots may be untied, but uneven dryness can still occur

Engineering Contradiction:

Improveknot preventionVSAvoiddryness uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #23Feedback

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

The method effectively addresses the inefficiencies by launching untangling operations only when needed, enhancing drying efficiency and reducing energy consumption and motor wear, while ensuring even dryness.

Implementation Method 1

detecting values indicative of the temperature of the drying air exiting the drum

Methodology Applied

Scientific EffectTemperature detection:

Implementation Method 2

the heat exchange between the hot air and the wet clothes

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

the heat released by the air allows the evaporation of the water from the clothes

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentEP2726665B1Method for operating a tumble dryer

Publication Date: 2015.04.08 ELECTROLUX HOME PROD CORP NV

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AI summary

A method for operating a laundry dryer having a rotatable drum for accommodating clothes to be dried and an apparatus for circulating drying air through the drum, the method comprises the steps of performing a drying cycle selected by a user, wherein the drying cycle comprises predetermined drum movements over time depending on the cycle selected, detecting values indicative of the temperature of the drying air exiting the drum, based on said detected values, determining that the clothes inside the drum are in tangling conditions and starting an untangling operation for untie the clothes inside the drum, wherein the untangling operation comprises the modification of the predetermined drum movements and the modification comprises at least one of the following: stopping the rotation of the drum, reversing the rotation of the drum, modifying the speed of rotation of the drum, at the end of the untangling operation, either resuming the predetermined drum movements associated to the drying cycle that was running before starting the untangling operation, or performing drum movements over time different from the predetermined drum movements associated to the drying cycle that was running before starting the untangling operation.