Electrode Holder Labyrinth Seal for High-Voltage Powder Spray Guns

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Solution Overview

Problem

Powder spray guns operating with high voltage pose a risk of explosion due to ignitable partial discharges and flashovers, especially when manually removable parts are not securely locked in place, necessitating a solution that maintains safety in both assembled and disassembled states.

Innovation Solution

The electrode holder for high-voltage powder spray guns features a concentric annular groove and ring-shaped web, forming a labyrinth with a cap nut to create an air gap and prevent high-voltage exposure, along with a snap-in connection mechanism to securely lock the electrode holder and nozzle in place, reducing the risk of ignition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manually removable parts are designed to be easily detachable for maintenance, then ease of operation and maintenance is improved, but safety is worsened due to risk of explosion from improper assembly

Engineering Contradiction:
Improveease of maintenanceVSAvoidsafety
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

A guide lug acts as an intermediary component between the spray nozzle and electrode holder, ensuring proper alignment and positioning. This mechanical guide structure prevents improper assembly while maintaining easy manual removal for maintenance, thus resolving the contradiction between ease of maintenance and safety

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The spray nozzle is nested within the electrode holder assembly, with the guide lug extending from the electrode holder to receive the spray nozzle. This nested structure ensures that components are properly positioned relative to each other, preventing unsafe misalignment while allowing simple manual assembly and disassembly

Inventive Principle:
Principle #7Nested doll (Nesting)

2Use of energy by moving object

If high voltage is applied to charge powder, then electrostatic charging effectiveness is improved, but risk of partial discharges and flashovers increases

Engineering Contradiction:
Improveelectrostatic charging effectivenessVSAvoidrisk of partial discharges and flashovers
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The grounding connection converts the potentially harmful high voltage energy into a controlled path to ground. By providing a dedicated grounding terminal connected to the electrode holder and spray nozzle, the system safely dissipates excess energy and prevents dangerous partial discharges and flashovers, thus converting the harmful high voltage effect into a protective mechanism

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The grounding connection acts as an intermediary safety mechanism between the high voltage electrode and the environment. This grounding path provides a controlled route for electrical discharge, preventing uncontrolled partial discharges and flashovers that could cause explosions, while allowing the high voltage to function effectively for powder charging

Inventive Principle:
Principle #24Intermediary (Mediator)

3Volume of moving object

If distance between high voltage electrode and surrounding components is reduced, then device compactness is improved, but field strength increases causing flashovers

Engineering Contradiction:
Improvedevice compactnessVSAvoidfield strength and flashover risk
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The electrical parameters of the system are changed by providing a grounding connection that alters the electrical potential distribution. This grounding modifies the electric field parameters, creating a reference potential that prevents excessive field strength buildup even when components are in close proximity, thus allowing compact design without increasing flashover risk

Inventive Principle:
Principle #35Parameter changes

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 design effectively reduces the risk of explosion and user injury by ensuring that the powder spray gun remains safe in both operational and maintenance states, even when manually removable parts are disassembled, by minimizing ignition energy and maintaining a secure high-voltage seal.

Implementation Method 1

The powder flows past the electrode and is thereby electrostatically charged. The high voltage applied to the electrode is typically between 20 kV and 80 kV.

Methodology Applied
Scientific EffectElectrostatic charging: Electrostatic Induction

Implementation Method 2

The annular groove, together with an annular rib of a retaining nut projecting into the annular groove, forms a labyrinth for the high voltage

Methodology Applied
Scientific EffectElectrical insulation through air gap: Dielectric

Data Source

PatentEP2638975B1Electrode holder and jet nozzle for a powder spray gun that can be operated with high voltage
Publication Date: 2020.02.26 WAGNER INT
  • EP2638975B1 patent drawingFigure 1~2
  • EP2638975B1 patent drawingFigure 3~4
  • EP2638975B1 patent drawingFigure 5~6

AI summary

The holder (9) has retaining web (23) for holding a high-voltage electrode (11) arranged in a powder channel (10). An annular groove is arranged concentrically with the powder channel and provided and open on the downstream side of the powder channel. A labyrinth for the high voltage is formed by the annular groove and the annular web of a cap nut (6), which locks the electrode holder. An air gap is formed between walls of the annular groove and the web. A snap-in groove is open in the radial direction. Independent claims are also included for the following: (1) a jet nozzle for a powder spray gun (2) a powder spray gun.