Fixed radial anode drum dryer
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Solution Overview
Problem
Existing clothes drying technologies using dielectric heating, especially at higher frequencies, are inefficient due to parasitic capacitance and require complex connections, leading to suboptimal energy transfer and heating uniformity.
Innovation Solution
A clothes dryer apparatus with a rotating conductive drum acting as a cathode and spatially fixed, insulated radial anodes for RF capacitive coupling, minimizing parasitic capacitance and using low RF frequencies for efficient dielectric heating, along with air flow for moisture removal and cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high frequency electromagnetic waves are used for dielectric heating, then heating capability is improved, but parasitic capacitance increases and heating uniformity deteriorates
Solution Approach 1:
The patent changes the operating frequency parameter from high frequency (microwave range) to low frequency (RF range of 1-50 MHz). This parameter change reduces parasitic capacitance effects while maintaining effective dielectric heating through ion drag mechanisms, resolving the contradiction between heating capability and parasitic capacitance
Solution Approach 2:
Instead of using the conventional high-frequency approach where electromagnetic waves propagate freely, the patent inverts the approach by using low-frequency RF fields where the enclosure acts as a capacitor rather than a resonant cavity. This inversion eliminates parasitic capacitance issues while achieving effective heating through capacitive coupling
2Power
If complex connections are used to achieve dielectric heating, then heating function is improved, but device complexity increases
Solution Approach 1:
The conductive drum serves multiple functions simultaneously: it acts as the heating chamber, provides capacitive coupling through its conductive surface, and functions as one of the capacitor plates. This multi-functionality eliminates the need for separate connection structures, reducing device complexity while maintaining effective heating
Solution Approach 2:
The drum's own conductive surface is utilized to provide the necessary capacitive coupling for RF heating. The drum structure itself serves the dual purpose of containing the load and providing the electrical interface for RF power transfer, eliminating the need for additional specialized connection components
3Loss of energy
If air gap between capacitor plates and load is reduced, then energy transfer efficiency is improved, but device complexity increases
Solution Approach 1:
The conductive drum maintains an equipotential surface that closely follows the contour of the clothes load. This equipotential configuration ensures uniform electric field distribution and minimal air gaps across the entire loading surface, maximizing energy transfer efficiency without requiring complex adjustment mechanisms
Solution Approach 2:
The drum's curved surface naturally conforms to the shape of the clothes load, maintaining consistent and minimal air gaps throughout the loading area. This geometric configuration optimizes capacitive coupling and energy transfer efficiency while avoiding the need for complex mechanical adjustment systems
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 configuration enhances energy conversion efficiency, reduces costs, and achieves uniform heating and faster drying by minimizing parasitic capacitance and using low RF frequencies, while simplifying connections and improving heating uniformity.
Implementation Method 1
Dielectric heating involves the heating of materials by dielectric loss. A changing electric field across the dielectric material (in this case, a load of clothes) causes energy to be dissipated as the molecules attempt to line up with the continuously changing electric field, creating friction.
Implementation Method 2
In conductive liquids such as salt water, 'ion drag' from using lower RF frequencies causes heating, as charged ions are 'dragged' more slowly back and forth in the liquid under influence of the electric field, striking liquid molecules in the process and transferring kinetic energy to them, which is eventually translated into molecular vibrations, and thus into thermal energy.
Data Source
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AI summary
A clothes dryer apparatus (99) comprising an electrically conductive, grounded, generally cylindrical rotatable drum (13) having a hollow interior adapted to contain a load (15) of wet clothes to be dried. The drum's (13) exterior surface (27) is partially indented to form one or more integral, generally ring-shaped insulated notches (10). An electrically conductive, generally flat arcuate anode (11) is positioned within each notch (10), with no physical contact between an anode (11) and its corresponding notch (10). Each anode (11) is spatially fixed with respect to the rotatable drum (13), and is electrically isolated from conductive portions of the drum (13). A source (21) of RF power (12), operating at a single fixed frequency, is coupled to each anode (11).