Discharge Unit With Inversely Tapered Through-Hole for Stable Spark Discharge

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Solution Overview

Problem

The existing discharge units for water treatment experience instability due to the increase in size of the through-hole caused by glow discharges, leading to thermal destruction and reduced electrical resistance, which hinders stable discharge operations.

Innovation Solution

An alternating power source is used to apply voltage to the electrodes, maintaining a spark discharge by alternating polarity before transitioning to glow discharge, preventing thermal destruction and stabilizing the discharge, with a waveform having equal positive and negative excursions and an inversely tapered through-hole design to trap bubbles and maintain discharge stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a constant DC voltage is applied to the electrodes, then the current density increases to generate discharge, but the through-hole size increases due to thermal destruction from glow discharge

Engineering Contradiction:
Improvecurrent densityVSAvoidthrough-hole size
Core Design Contradiction:
PowerVSStability of the object's composition

Solution Approach 1:

The patent applies periodic reversal of voltage polarity to the electrodes, switching between positive and negative polarity at regular intervals. This periodic action prevents continuous glow discharge by interrupting the thermal accumulation process, thereby maintaining stable through-hole dimensions while still achieving effective discharge for water purification

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent changes the electrical parameter from constant DC voltage to alternating voltage with periodic polarity reversal. This parameter change transforms the discharge mode from continuous glow discharge to intermittent spark discharge, controlling the thermal effects and preventing through-hole enlargement while maintaining adequate current density for purification

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the through-hole size increases, then the electrical resistance decreases, but the current density becomes insufficient for stable discharge

Engineering Contradiction:
Improvedischarge stabilityVSAvoidthrough-hole dimension
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

By periodically reversing the voltage polarity, the system maintains adequate current density through spark discharges without allowing continuous glow discharge to enlarge the through-hole. This periodic control ensures both discharge stability and through-hole dimensional precision are maintained simultaneously

Inventive Principle:
Principle #19Periodic action

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 approach ensures a stable, low-temperature spark discharge without thermal destruction of the through-hole, reducing electrode degradation and maintaining discharge stability, independent of water conductivity.

Implementation Method 1

A spark discharge is thus generated in the through-hole (35) with no glow discharge generated

Methodology Applied
Scientific EffectSpark discharge: Electric Spark

Implementation Method 2

the form of the discharge changes from the spark discharge to the glow discharge

Methodology Applied
Scientific EffectGlow discharge: Electric Glow Discharge

Implementation Method 3

This prevents thermal destruction of the through-hole (35) caused by the glow discharge

Methodology Applied
Scientific EffectThermal destruction: Thermal Shock

Implementation Method 4

both ends (35a) of the through-hole (35) expand outward to be inversely tapered... to trap bubbles and maintain discharge stability

Methodology Applied
Scientific EffectBubble trapping: Physical Containment

Data Source

PatentEP2902369B1Method of operating a discharge unit
Publication Date: 2019.02.20 DAIKIN INDUSTRIES LTD
  • EP2902369B1 patent drawingFigure 1
  • EP2902369B1 patent drawingFigure 2
  • EP2902369B1 patent drawingFigure 3

AI summary

A discharge unit includes an alternating high-voltage generator (33), a pair of electrodes (31 and 32) in water, the pair being configured to receive a voltage from the high-voltage generator (33), and an insulating divider (15) configured to separate the pair of electrodes (31 and 32) from each other in the water, and having a small discharge hole (35) defining a path of current to flow between the pair of electrodes (31 and 32). The voltage is applied to the pair of electrodes (31 and 32) to generate an electric discharge in the discharge hole (35).