Laundry drying machine and controlling method of laundry drying machine
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Solution Overview
Problem
Conventional laundry drying machines face issues such as low drying efficiency, high energy consumption, local overheating leading to color transfer and damage, and mechanical stress causing shrinkage, especially in dielectric heating systems.
Innovation Solution
A laundry drying machine with a fixed anode electrode and rotating drum, controlled by a system that adjusts power and rotation speed based on electric field reflectivity to maintain optimal heating and mixing while minimizing energy use and mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hot air is supplied to the drum to dry clothes, then drying speed is improved, but energy consumption increases and drying performance per power consumed decreases
Solution Approach 1:
The patent replaces the thermal convection system (hot air circulation) with a dielectric heating system using RF electromagnetic fields. The RF generator applies high-frequency electric fields directly to the laundry, causing water molecules to vibrate and generate heat through dielectric loss, eliminating the need for hot air supply and exhaust systems.
Solution Approach 2:
The patent employs periodic alternation between RF heating mode and mechanical rotation mode. During RF heating, the drum rotates at low speed to prevent overheating; during mechanical rotation, the drum rotates at higher speed to redistribute laundry and prevent local overheating, creating a cyclic pattern that optimizes both drying efficiency and energy utilization.
2Productivity
If high temperature air is used to reach evaporation temperature, then drying efficiency is improved, but clothes are damaged due to denaturation
Solution Approach 1:
The patent applies dielectric heating which generates heat uniformly throughout the volume of the laundry rather than heating from the outside in. The RF electromagnetic fields penetrate the clothes and cause water molecules throughout the fabric to vibrate simultaneously, achieving evaporation temperature throughout the laundry bulk without creating high-temperature zones on the surface that would damage the fabric.
Solution Approach 2:
The patent replaces thermal convection heating with dielectric heating using RF electromagnetic fields, which directly energize water molecules within the fabric matrix, avoiding the need for high-temperature air that causes denaturation and damage to clothing fibers.
3Use of energy by moving object
If the drum is stopped during RF power supply to form constant electric field, then heating efficiency is improved, but local overheating occurs causing color transfer
Solution Approach 1:
The patent transitions from a static drum configuration to a dynamic system where the drum rotates at controlled speeds during RF heating. The rotation speed is optimized to balance two requirements: slow enough to maintain sufficient electric field constancy for efficient dielectric heating, but fast enough to continuously redistribute laundry items and prevent localized heat accumulation that causes overheating and color transfer.
Solution Approach 2:
The patent employs periodic alternation between RF heating mode and mechanical rotation mode. During RF heating, the drum rotates at low speed to prevent overheating; during mechanical rotation, the drum rotates at higher speed to redistribute laundry and prevent local overheating, creating a cyclic pattern that optimizes both drying efficiency and energy utilization.
4Manufacturing precision
If the drum rotates at high speed to mix and evenly heat laundry, then heating uniformity is improved, but mechanical stress causes shrinkage
Solution Approach 1:
The patent implements variable speed rotation where the drum rotates at different speeds depending on the operational phase. During RF heating, rotation speed is kept low (e.g., 1-5 rpm) to minimize mechanical stress and shrinkage. During intermittent mechanical rotation phases, speed is increased to redistribute laundry for uniform heating. This dynamic speed adjustment achieves heating uniformity without excessive mechanical stress.
5Device complexity
If reflected waves are not managed during RF heating, then system simplicity is maintained, but machine is damaged due to reflected waves
Solution Approach 1:
The patent incorporates a reflection detection system that monitors the RF electromagnetic field for reflected waves. When reflections are detected (indicating impedance mismatch or loading conditions), the system automatically adjusts RF power output or drum rotation speed to eliminate the reflection condition. This feedback mechanism protects the RF generator from damage while maintaining system simplicity by using electronic control rather than complex mechanical impedance matching devices.
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
Prevents local overheating and color transfer, reduces energy consumption, and minimizes shrinkage by dynamically controlling power and rotation speed, enhancing drying efficiency and protecting the machine from reflected waves.
Implementation Method 1
an anode electrode spaced apart from the drum, fixed to the cabinet, to generate an electric field in the drum
Implementation Method 2
the subject to be dried rotates inside the drum by centrifugal force and falls due to gravity during the rotation
Implementation Method 3
the subject to be dried rotates inside the drum by centrifugal force and falls due to gravity during the rotation
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention relates to a laundry drying machine and a control method of the laundry drying machine, and includes a cabinet, a drum that is rotatably installed in the cabinet to accommodate a subject to be dried, and an electric field generator that is spaced apart from the drum and generates an electric field inside the drum when power is applied. The electric field generator includes an anode electrode that is spaced apart from the drum, fixed to the cabinet, and applies the electric field to the subject to be dried accommodated in the drum, a power supply unit that supplies the power to the anode electrode, and a matcher that is provided in the cabinet and matches source impedance of the power and an impedance of a load side. When the reflectivity of the electric field exceeds a predetermined ratio, the rotation speed of the drum is reduced to lower the reflectivity of the electric field, and thus, there is an effect of preventing damage to equipment such as the matcher due to the reflected wave.