Two-Part Field Unit Mounting for Wireless Signals Through Metal Walls

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Solution Overview

Problem

Existing field devices with metal housings face challenges in wireless communication due to electromagnetic wave interference, requiring complex cable feedthroughs and additional seals, which are not feasible in all installation scenarios, especially in metal containers.

Innovation Solution

A fastening device for field devices is designed in two parts, allowing one part to penetrate the wall, enabling radio communication by positioning the antenna outside the container, with a mechanical and electronic interface for secure attachment and signal transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a metal housing is used for the field device, then mechanical stability and resistance to environmental influences are improved, but wireless communication is blocked due to electromagnetic wave interference

Engineering Contradiction:
Improvemechanical stabilityVSAvoidwireless communication
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The mounting device is divided into two separate parts: a first part with an antenna that can be positioned outside the metal container, and a second part that remains inside with the field device. This segmentation allows the antenna to be located in a position where it can transmit radio waves effectively, while the field device remains protected inside the metal housing.

Inventive Principle:
Principle #1Segmentation

2Reliability

If a cable feedthrough is used to route communication signals outside the housing, then wireless communication is enabled, but the housing design becomes more complex and requires additional explosion-proof seals

Engineering Contradiction:
Improvewireless communicationVSAvoidhousing design
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The antenna function is extracted from the field device housing and integrated into the separate mounting device. The antenna is positioned in the first part of the mounting device that extends outside the container wall, eliminating the need for cable feedthroughs and complex sealing arrangements while maintaining wireless communication capability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If a glass window is added to the metal housing for radio transmission, then wireless communication is enabled, but the connection becomes directional and usability is limited

Engineering Contradiction:
Improvewireless communicationVSAvoidusability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

Instead of creating a directional transmission path through a glass window in the housing wall, the antenna is extended into a separate spatial dimension by positioning it in the first part of the mounting device that protrudes outside the container. This allows omnidirectional or multi-directional radio wave transmission, greatly improving usability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Adaptability or versatility

If a two-part mounting device is used with one part penetrating the wall, then flexible installation and wireless communication are enabled, but the mounting device structure becomes more complex

Engineering Contradiction:
Improveinstallation flexibilityVSAvoidmounting device structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The two-part mounting device serves multiple functions: it provides mechanical mounting of the field device to the container wall, enables wireless communication by positioning the antenna outside the metal housing, and maintains explosion-proof sealing through the sealing element. This multi-functionality justifies the slightly increased structural complexity.

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

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

Facilitates flexible installation and uninterrupted wireless communication without the need for complex cable feedthroughs or additional seals, reducing installation complexity and ensuring reliable radio connectivity.

Implementation Method 1

the use of radio modules is incompatible with metal housings. If a radio transmitter/receiver is located inside the sensor housing along with the remaining sensor electronics of a field device, such as a level sensor, the metal housing walls prevent the propagation of electromagnetic waves and thus the desired radio connection.

Methodology Applied
Scientific EffectElectromagnetic wave propagation: Electromagnetic Induction

Data Source

PatentEP3879235B1Mounting device for a field unit
Publication Date: 2025.06.25 VEGA GRIESHABER GMBH & CO
  • EP3879235B1 patent drawingFigure 1~2
  • EP3879235B1 patent drawingFigure 3~5

AI summary

The present invention relates to a self-contained field device for process automation comprising a sensor, a radio module and a mounting device for attaching the field device to a wall, characterized in that the mounting device is designed to be at least two-part and is configured such that a first, sensor-side part of the mounting device can be mounted from a first side of the wall and a second part of the mounting device can be mounted from a second side of the wall, wherein the parts of the mounting device form a mechanical first interface penetrating the wall and the field device can thus be attached to the wall.