Ozone Generator Discharge Suppression via Flexible Metal Plate

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Solution Overview

Problem

Existing ozone generating apparatuses face challenges in increasing discharge power density without heat-related issues, particularly due to cooling unevenness near the end portion of the metal tube, which can lead to dielectric breakdown and reduced ozone production.

Innovation Solution

A hermetically sealed ozone generating apparatus with a discharge suppressing member formed of a metal plate, curled into a circular shape with overlapping portions and slits, is used to minimize gaps between the suppressing member and the glass tube, ensuring effective cooling and reduced discharge occurrence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If discharge power density is increased to enhance treatment capacity, then ozone production increases, but heat-related problems and cooling unevenness worsen

Engineering Contradiction:
Improveozone productionVSAvoidtemperature uniformity
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The discharge suppressing member is selectively positioned at the end portion of the dielectric tube where cooling is insufficient and temperature rises excessively. This local intervention addresses the specific thermal problem zone without affecting other regions, allowing high discharge power density to be maintained in the main discharge region while preventing dielectric breakdown at the vulnerable end portion.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The discharge suppressing member acts as an intermediary element between the high-power discharge region and the cooling system. It mediates the thermal balance by suppressing discharge at the end portion where cooling water flow is reduced, thereby preventing excessive heat accumulation and enabling higher overall discharge power density to be applied safely.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If discharge suppressing member is placed at tube sheet portion to suppress discharge, then temperature decreases and average power increases, but discharge gap must be reduced to several tens μm which is difficult to maintain with rigid structures

Engineering Contradiction:
Improvetemperature at tube sheet portionVSAvoidgap uniformity
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The discharge suppressing member is designed with a flexible structure that can dynamically adapt to the dielectric tube's outer diameter variations. The member includes a bent portion that flexes to maintain consistent contact pressure and gap uniformity along the entire circumference, compensating for manufacturing tolerances and thermal expansion effects.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The discharge suppressing member is formed with a curved surface that matches the cylindrical geometry of the dielectric tube. This curved configuration ensures uniform gap distribution around the circumference, preventing localized discharge points and maintaining consistent temperature suppression along the tube sheet portion.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Object-affected harmful factors

If insulating material is filled in gap to suppress discharge, then discharge is suppressed, but source gas flow is blocked

Engineering Contradiction:
Improvedischarge suppressionVSAvoidsource gas flow
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The discharge suppressing member is constructed as a thin-walled flexible structure that can be positioned within the discharge gap without completely blocking it. The member's design allows source gas to flow through or around it while maintaining sufficient proximity to suppress discharge, balancing thermal control with gas flow requirements.

Inventive Principle:
Principle #30Flexible shells and thin films

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 solution effectively suppresses discharge and heat buildup, allowing for increased feedable power density and ozone production without dielectric breakdown, enhancing the apparatus's efficiency and reliability.

Implementation Method 1

Heat generated by a discharge is taken away by cooling water that circulates outside the metal tube

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

cooling water that circulates outside the metal tube

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

applying a high-voltage AC voltage between the metal tube and the metal film on the inner surface of the dielectric tube to thereby generate an AC field in the gap through the dielectric material

Methodology Applied
Scientific EffectElectric field: Electric Field

Implementation Method 4

the discharge suppressing member and the metal tube become at the same potential due to their electrical connection

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2842907B1Ozone generator
Publication Date: 2019.01.02 MITSUBISHI ELECTRIC CORP
  • EP2842907B1 patent drawingFigure 1
  • EP2842907B1 patent drawingFigure 2
  • EP2842907B1 patent drawingFigure 3

AI summary

An ozone generating apparatus which is provided with a discharge suppressing member (10) formed of a metal plate and covering an outer circumferential surface of a portion of a dielectric tube (2) facing to a tube sheet (90), the discharge suppressing member being electrically in contact with a metal tube (1) or the tube sheet (90), wherein the discharge suppressing member is formed by curling the metal plate longer than a circumferential length of the dielectric tube into a circular shape so as to have an overlapping portion (14), and by joining together, in the overlapping portion, a part of the metal plate placed outside and a part of the metal plate placed inside, at a near-end portion of the metal plate placed outside in the overlapping portion, and wherein the discharge suppressing member has, on the part of the metal plate placed outside in the overlapping portion, a spring portion (17) stretched in a circumferential direction.