Conductive Washer Grounding for ATEX Valve Stems

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Solution Overview

Problem

Existing valve systems in ATEX environments lack effective grounding and electrical continuity between moving parts, particularly the valve stem and the stuffing box, due to non-conductive materials, which can lead to electrostatic discharge issues.

Innovation Solution

A conductive washer with flexible legs is integrated into the valve system, ensuring electrical contact between the valve stem and the stuffing box, reducing friction and maintaining grounding without excessive wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If non-conductive materials (plastic piston, PTFE disc seal) are used in the valve system, then friction and wear are reduced, but electrical continuity and grounding are lost

Engineering Contradiction:
Improveelectrical continuityVSAvoidelectrostatic discharge
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The electrical continuity function is segmented from the main valve stem and assigned to a separate conductive washer component. This washer is positioned between the valve stem and stuffing box, creating a dedicated grounding path that is independent of the valve stem's primary sealing and movement functions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A conductive washer is introduced as an intermediary component between the valve stem and stuffing box. This washer serves as a mediator that transfers electrical charge from the moving valve stem to the stationary stuffing box, enabling grounding without requiring direct metal-to-metal contact between the stem and stuffing box.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a conductive washer with flexible legs is used, then electrical continuity is achieved, but device complexity increases

Engineering Contradiction:
Improvegrounding continuityVSAvoidvalve system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The conductive washer is designed to perform multiple functions simultaneously: it provides electrical continuity for grounding, acts as a mechanical spacer to maintain proper positioning, and through its flexible legs, accommodates misalignment between the valve stem and stuffing box. This multi-functionality reduces the need for additional separate components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The flexible legs of the washer can change their geometric parameters (bending angle, contact point position) to adapt to variations in valve stem position and alignment. This flexibility allows the washer to maintain electrical contact under varying operational conditions without requiring precise manufacturing tolerances or additional adjustment mechanisms.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the washer maintains constant contact with the valve stem, then grounding is reliable, but friction and wear increase

Engineering Contradiction:
Improveelectrical contactVSAvoidvalve stem wear
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The flexible legs of the washer provide dynamic contact with the valve stem, allowing the contact points to adapt as the stem moves. The flexibility enables the washer to maintain electrical continuity through varying contact conditions without requiring constant firm pressure, thereby reducing wear on the valve stem while ensuring reliable grounding.

Inventive Principle:
Principle #15Dynamics

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 conductive washer provides reliable electrical continuity and grounding, preventing electrostatic discharges while minimizing friction and wear on the valve stem, enhancing safety in ATEX environments.

Implementation Method 1

the washer comprising an electrically conductive material... ensures electrical contact between the valve stem and the stuffing box

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

The flexibility of the legs ensures positive contact with sliding stem for lifetime without adding too much friction to its movement

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4244509B1Valve system for ATEX environment
Publication Date: 2025.08.20 ASCO SAS
  • EP4244509B1 patent drawingFigure 1
  • EP4244509B1 patent drawingFigure 2~3
  • EP4244509B1 patent drawingFigure 4

AI summary

A valve system (1) comprising a valve having a valve stem (50), a valve body (20) and a stuffing box (30) assembled to the valve body, the valve system comprising a washer (60) in contact with the stem (50) and the stuffing box (30), the washer (60) comprising an electrically conductive material.