Resonant RF Diathermy Applicator with High-Resistance Inductor
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Solution Overview
Problem
Existing RF diathermy applicators face challenges in maintaining consistent body area coverage and preventing overheating, especially on large muscle groups like the back, abdomen, and neck, due to the absence of additional materials, leading to discomfort and potential injury.
Innovation Solution
A new heat applicator design incorporating a high resistivity wire for the inductor, such as nickel or steel, to maintain a near-resonant circuit under varying conditions, along with internal non-adjustable tuning components and shielding to minimize radiation, eliminating the need for operator tuning and ensuring consistent heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If prior RF diathermy apparatus are used on large planar muscle groups without additional materials, then the device structure is simple, but the patient's subcutaneous fat layers overheat causing discomfort and injury
Solution Approach 1:
The patent introduces an intermediary material (such as a towel or specialized applicator material) between the RF diathermy coil and the patient's skin. This intermediary acts as a heat sink and thermal buffer, preventing direct overheating of the subcutaneous fat layers while still allowing effective RF energy transmission to the target muscle groups. The intermediary material absorbs excess heat and distributes it safely, resolving the contradiction between simple device structure and prevention of harmful overheating.
2Use of energy by moving object
If resonant circuits are tuned for optimal performance, then heating efficiency is improved, but the circuit requires retuning when external conditions change
Solution Approach 1:
The patent employs a variable capacitor that can be adjusted or automatically tuned to maintain optimal resonant conditions as external conditions change (such as patient movement, positioning, or tissue impedance variations). This dynamic tuning capability allows the circuit to adapt to changing conditions while maintaining high heating efficiency, eliminating the need for manual retuning and improving ease of operation.
Solution Approach 2:
The patent changes the electrical parameters of the resonant circuit by incorporating variable capacitance or inductance elements that can be adjusted to maintain resonance. By dynamically changing these electrical parameters in response to external conditions, the system maintains optimal heating efficiency without requiring complete retuning of the circuit, thus improving ease of operation while preserving heating efficiency.
3Adaptability or versatility
If coil radiation is allowed to operate in free-space, then environmental regulation compliance is achieved, but incidental radiation occurs
Solution Approach 1:
The patent nests the RF coil within a shielding structure or applicator housing that contains and directs the electromagnetic radiation. This nested configuration allows the device to operate in free-space environments while the outer shielding layer captures and contains incidental radiation, preventing it from radiating unnecessarily into the environment. This resolves the contradiction by maintaining free-space operational versatility while eliminating harmful incidental radiation through the nested shielding structure.
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 design achieves consistent tissue heating across varying external conditions without the need for retuning, reducing the risk of overheating and improving user comfort by maintaining a wide bandwidth and minimizing incidental radiation.
Implementation Method 1
The coil radiates the target tissue with energy in the form of both electric and magnetic fields, which cause currents to flow in perfuse tissue. Resistive losses in this tissue causes warming.
Implementation Method 2
Resistive losses in this tissue causes warming.
Implementation Method 3
A new heat applicator design incorporating a high resistivity wire for the inductor, such as nickel or steel, to maintain a near-resonant circuit under varying conditions
Data Source
AI summary
A resonant radio frequency diathermy heat applicator, including a flexible pad, an inductive coil with moderate defined resistance, fixed tuning capacitors, connecting cable and shielding that is broadly tuned to the signal source in a manner that eliminates the requirement for variable tuning elements.