Method for removing foreign objects from laundry in a laundry drying appliance and laundry drying appliance
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Solution Overview
Problem
Existing laundry drying appliances struggle to efficiently remove foreign objects such as hair and lint due to their lightweight and tendency to float in air, with existing methods often requiring separate pre-treatment or inefficient removal processes.
Innovation Solution
A method and appliance that utilize variable drum and air flow rates, alternating between high and low speeds to mechanically dislodge and air-flush foreign objects, with humidity sensing to optimize the process and reduce energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drum rotates at high speed continuously, then the air flow rate is high which helps remove foreign objects, but the mechanical impact on laundry is insufficient to detach foreign objects effectively
Solution Approach 1:
The drum rotation speed is varied periodically between high and low speeds. During high-speed phases, strong air flow removes detached foreign objects. During low-speed phases, increased mechanical impact detaches foreign objects from laundry. This periodic alternation resolves the contradiction by applying both high air flow and high mechanical impact at different times.
2Force
If the drum rotates at low speed, then the mechanical impact on laundry is high which detaches foreign objects, but the air flow rate is insufficient to remove foreign objects effectively
Solution Approach 1:
The system alternates between low-speed phases (providing high mechanical impact for detachment) and high-speed phases (providing high air flow for removal). This periodic action ensures that both detachment and removal functions are fulfilled effectively.
3Productivity
If high air flow rate is used continuously, then foreign objects are removed efficiently, but energy consumption increases
Solution Approach 1:
The air flow rate is varied periodically rather than maintained at high levels continuously. High air flow is applied only during high-speed phases when foreign objects need to be removed, while low-speed phases use reduced air flow when mechanical impact is sufficient for detachment. This reduces overall energy consumption while maintaining removal efficiency.
4Productivity
If the drum rotates at variable speeds, then foreign objects are removed effectively, but the control system complexity increases
Solution Approach 1:
The control system implements a simple periodic cycle alternating between high-speed and low-speed phases. This regular periodic pattern is easier to control than arbitrary variable speed profiles, reducing control system complexity while achieving effective foreign object removal through the alternating mechanical and aerodynamic actions.
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
Efficient removal of hair and lint by alternating drum speeds and air flow rates, enhancing mechanical impact and airflow to dislodge and remove foreign objects effectively, while optimizing energy use and reducing electrostatic attraction.
Implementation Method 1
The necessary scraping movement is created by the inertia and centrifugal force of the scraper during rotation of the tumble dryer drum.
Implementation Method 2
The necessary scraping movement is created by the inertia and centrifugal force of the scraper during rotation of the tumble dryer drum.
Implementation Method 3
a heating device configured to heat the drying air to be conveyed by the conveying element into the drum
Implementation Method 4
a drying air conveying element configured to convey drying air into the drum
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 2C~2D
AI summary
Laundry drying appliance (1), being operable in a foreign objects removal mode which comprises: step 1: decreasing the speed of the drive unit (26) from a high-speed state, in which the drive unit (26) is operated to rotate the drum (12) at a first rotational drum speed and to drive the conveying element (18) to output a first flow rate of drying air, to a low-speed state, in which the drive unit (26) is operated to rotate the drum (12) at a second rotational drum speed and to drive the conveying element (18) to output a second flow rate of drying air, wherein the first rotational drum speed is higher than the second rotational drum speed and the first flow rate of drying air is higher than the second flow rate of drying air, and step 2: increasing the speed of the drive unit (26) from the low-speed state to the high-speed state.