Laundry drying apparatus and method of controlling a drying cycle in a laundry drying apparatus
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Solution Overview
Problem
Existing laundry drying technologies do not effectively address the need for gentle treatment of delicate items, often resulting in creases and inefficient energy use.
Innovation Solution
A laundry drying apparatus with a control unit that alternates drum rotation between main and counter rotation directions and adjusts air flow rates between two phases, with slower rotation and lower air flow in the first phase to minimize mechanical stress and higher air flow in the second phase for efficient drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drum rotates continuously at high speed to improve drying efficiency, then productivity increases, but delicate laundry suffers mechanical stress and creases
Solution Approach 1:
The drum rotation is controlled to alternate between forward and reverse directions in periodic cycles. During each cycle, the drum rotates forward for a predetermined time period, then reverses for a shorter time period, creating a periodic motion pattern that gently agitates delicate laundry while maintaining drying progress
Solution Approach 2:
The drum rotation speed and direction are dynamically adjusted during the drying cycle. The system transitions from continuous high-speed rotation to variable speed rotation with periodic direction changes, adapting the mechanical action to protect delicate fabrics while preserving drying effectiveness
2Productivity
If high velocity air flow is used throughout the drying cycle to reduce drying time, then productivity increases, but energy consumption increases
Solution Approach 1:
The air flow rate is controlled to alternate between high and low rates in periodic cycles synchronized with drum rotation phases. High air flow is applied during forward drum rotation when drying efficiency is maximized, while low air flow is applied during reverse rotation when mechanical agitation is prioritized, reducing overall energy consumption
Solution Approach 2:
The air flow rate is dynamically adjusted based on the drum rotation phase. The system transitions from static high air flow to dynamic air flow control, varying the blower intensity to match the mechanical agitation needs at different cycle stages, optimizing the balance between drying speed and energy use
3Manufacturing precision
If the drum rotates in alternating directions with frequent reversals to prevent creases, then laundry quality improves, but drying time increases
Solution Approach 1:
The drum follows a periodic rotation pattern with forward rotation periods significantly longer than reverse rotation periods. This asymmetric periodic motion provides sufficient mechanical agitation to prevent creases during the brief reverse phases while maintaining drying progress during the extended forward phases
Solution Approach 2:
The rotation parameters are optimized by setting the forward rotation time to be substantially longer than the reverse rotation time. This parameter adjustment ensures that the majority of the cycle time is devoted to productive drying while brief reverse intervals provide adequate fabric redistribution to prevent creases
4Use of energy by moving object
If low air flow rate is maintained throughout the drying cycle to reduce energy consumption, then energy efficiency improves, but drying time increases
Solution Approach 1:
The air flow operates in periodic high-low cycles that synchronize with drum rotation phases. High air flow periods provide rapid moisture removal when the drum position maximizes air-laundry contact, while low air flow periods reduce energy consumption during reverse rotation when mechanical agitation is the primary action
Solution Approach 2:
The air flow rate transitions from a static low setting to a dynamic control strategy that adjusts intensity based on drum rotation phase and drying needs. This dynamic adjustment allows the system to achieve effective drying with lower average energy consumption by applying high air flow only when most beneficial
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 ensures gentle treatment of delicate laundry, reduces creases, and enhances energy efficiency by optimizing drum rotation speed and air flow, allowing for shorter drying times while maintaining gentle mechanical agitation.
Implementation Method 1
a heating element arranged in the channel arrangement for heating the drying air
Implementation Method 2
a blower arranged in the channel arrangement adapted to convey the drying air
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a method of controlling a drying cycle for drying delicate laundry in a laundry drying apparatus, in particular in a dryer or in a washer-dryer, wherein the laundry drying apparatus comprises a cabinet, a rotatable drum adapted to receive laundry to be dried, and a drying air channel arrangement designed to guide drying air through the drum for drying the laundry in the drum. The drying air is heated by a heating element and a blower is arranged in the channel arrangement adapted to convey the drying air. A drum motor is adapted to rotate the drum selectively in a main rotation direction (58) and in a counter rotation direction (66). The method comprises a drying phase sequence (60) having a first drying phase (62) and subsequently a second drying phase (64). In the first drying phase (62) the drum is rotated alternately in the main and the counter rotation direction (58, 66) while the drying air is conveyed at a first average flow rate through the drum. In the second drying phase (64) the drum is rotated in the main rotation direction (58) while the drying air is conveyed at a second average flow rate through the drum, wherein the first average flow rate is lower than the second average flow rate. Further the invention relates to a laundry drying apparatus adapted to implement the method.