Flameproof Feed-Through Impedance Control

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Solution Overview

Problem

Existing flameproof feed-throughs for Coriolis mass flowmeters and densitometers face limitations in controlling characteristic impedance, leading to restricted signal frequency capabilities and increased manufacturing complexity and cost due to the use of cemented joints and plastic over-molding processes.

Innovation Solution

A flameproof feed-through design featuring a clamped interface between body portions and a feed-through element, which minimizes gaps and maintains a predetermined flame path length, allowing for precise control of impedance and simplified manufacturing through machining processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cemented joints and plastic over-molding processes are used to create flameproof feed-throughs, then flameproof integrity is achieved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveflameproof integrityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the cemented joint and plastic over-molding processes from the feed-through construction. Instead, it uses a mechanically assembled design with a bushing, gasket, and housing that achieves flameproof integrity through precision machining and mechanical compression, thereby removing the manufacturing complexity associated with cementing and molding processes.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the chemical bonding mechanism (cemented joints) and thermal processing (plastic over-molding) with a purely mechanical assembly system. The flameproof seal is achieved through a compressed gasket between machined surfaces, substituting chemical and thermal processes with mechanical compression and precision fitting.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If cemented joints and plastic over-molding processes are used to create flameproof feed-throughs, then flameproof integrity is achieved, but manufacturing cost increases

Engineering Contradiction:
Improveflameproof integrityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent removes the expensive cemented joint and plastic over-molding processes from the manufacturing workflow. The design uses standard mechanical components (bushing, gasket, housing) that can be manufactured using conventional machining processes, significantly reducing material and process costs while maintaining flameproof certification.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs a gasket as a relatively simple, replaceable component that provides the flameproof seal. This gasket can be a cost-effective element compared to the expensive cementing and molding processes, and if needed, can be replaced without replacing the entire feed-through assembly.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If traditional flameproof feed-through designs are used, then flameproof protection is provided, but impedance control capability is limited

Engineering Contradiction:
Improveflameproof protectionVSAvoidimpedance control capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by providing impedance control specifically at the conductor interfaces within the bushing. The bushing design allows for controlled impedance pathways for electrical signals while the rest of the assembly maintains its flameproof function. This localized impedance control enables the feed-through to accommodate high-frequency signals without compromising the overall flameproof protection.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2850400B1Flameproof electrical feed-through and method of forming such a feed-through
Publication Date: 2021.07.14 MICRO MOTION INC
  • EP2850400B1 patent drawingFigure 1
  • EP2850400B1 patent drawingFigure 2~3
  • EP2850400B1 patent drawingFigure 4

AI summary

A flameproof feed-through (200) includes a feed-through element (210) comprising a substantially planar shape, a first interface region (211), and a second interface region (212), wherein one or more conductors (217) extend between the first interface region (211) and the second interface region (212). The flameproof feed-through (200) further includes one or more body portions (220) assembled to the feed-through element (210), with the one or more body portions (220) holding the feed-through element (210) in position with respect to the aperture. The first interface region (211) of the feed-through element (210) extends at least partially to a first side (201) of the flameproof feed-through (200) and wherein the second interface region (212) of the feed-through element (210) extends at least partially to a second side (202) of the flameproof feed-through (200).