Sauna EMI Filter Circuit Reduces EMR to 2 mGauss

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Solution Overview

Problem

Existing sauna heating technologies emit significant electromagnetic radiation (EMR) due to alternating current usage, causing adverse health effects, and existing solutions are limited to specific heater types or require precise matching of carbon fiber heaters for effective EMR cancellation.

Innovation Solution

The implementation of an AC to DC converter circuit with EMI filter circuits to reduce EMR emissions, using a first-pass filter between the AC input and converter, and a second-pass filter between the converter output and the heater, along with optional EMF shielding, to power heaters safely with DC current.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If alternating current heaters are used in sauna rooms, then heating function is provided, but electromagnetic radiation is emitted causing adverse health effects

Engineering Contradiction:

Improveheating functionVSAvoidelectromagnetic radiation

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the alternating current electrical heating system with a direct current heating system. By converting AC power to DC power through a power converter and using EMI filter circuits, the system eliminates electromagnetic radiation while maintaining the heating function. This substitution of the electrical system type directly resolves the contradiction between providing heat and avoiding EMR.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces EMI filter circuits as intermediary components between the power source and the heater. These filter circuits act as mediators that allow electrical power to be transmitted while blocking electromagnetic radiation. The filter circuits are positioned at strategic points in the power transmission path to intercept and eliminate EMR before it can affect the sauna environment.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If carbon fiber heaters are used with opposite phase AC current to cancel EMR, then electromagnetic radiation is reduced, but the solution is limited to specific heater types and requires precise matching

Engineering Contradiction:

Improveelectromagnetic radiationVSAvoidheater type compatibility

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal solution that works with various heater types (carbon fiber, mica, ceramic, film, iron heat pipes, light tubes) by using EMI filter circuits in the power transmission path. This approach is not limited to specific heater technologies but provides EMR elimination across all heater types, significantly improving adaptability and versatility.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The EMI filter circuits serve as intermediary components that interface between the power source and any type of heater. These filters act as a universal mediator that can be applied to different heater technologies without requiring precise matching or specialized components, making the solution adaptable to various heater types.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If carbon fiber heaters with opposite phase AC current are used for EMR cancellation, then electromagnetic radiation is reduced, but manufacturing precision requirements increase

Engineering Contradiction:

Improveelectromagnetic radiationVSAvoidheater matching precision

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent replaces the precision-matching required heater configuration with a power conversion system that inherently eliminates EMR. By using AC to DC conversion with EMI filtering, the system achieves EMR elimination without requiring precise manufacturing tolerances or matched pairs of heaters, significantly reducing manufacturing precision requirements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses standard, off-the-shelf EMI filter circuits and power converter components rather than requiring precision-matched custom heaters. This approach uses readily available components with standard tolerances, eliminating the need for expensive precision manufacturing and complex matching procedures.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 significantly reduces EMR levels from 200 mGauss to less than 2 mGauss, creating a safer sauna environment by eliminating harmful electromagnetic radiation exposure.

Implementation Method 1

an EMI filter circuit. The filtered DC current is then used to power at least one heater in a sauna

Methodology Applied

Scientific EffectElectromagnetic filtering: Filter (electronic)

Implementation Method 2

an AC to DC converter circuit

Methodology Applied

Scientific EffectAC to DC conversion: Electromagnetic Induction

Implementation Method 3

The filtered DC current is then used to power at least one heater in a sauna

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS9078803B2Low EMI far infrared sauna room

Publication Date: 2015.07.14 DUNCAN RALEIGH

AI summary

A sauna that reduces EMI emissions in the sauna room by, in the preferred embodiment, passing the AC current through an EMI filter, converting it to DC current, and passing it through another EMI filter to remove any remaining irregularities.