Sensor Housing Edge Geometry for Hygienic Laser Welding

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Solution Overview

Problem

Existing temperature sensor housings for industrial process technology are not easily manufacturable and do not meet hygiene regulations, particularly in terms of edge distances and surface smoothness for laser welding.

Innovation Solution

A housing design for temperature sensors featuring a sleeve with a specific edge configuration at the second end section, allowing for easy laser welding to a sensor holder, with dimensions ensuring a smooth and hygienic weld seam, and a cross-section that is rotationally symmetrical or oval, facilitating efficient manufacturing and compliance with hygiene standards.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional flange designs are used in temperature sensor housings, then the housing structure is simple, but the housing does not meet hygiene regulations and is difficult to manufacture with smooth weld seams

Engineering Contradiction:
Improveweld seam smoothnessVSAvoidhousing manufacturability
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies local quality by creating a specific edge configuration only at the critical welding location (second end section of the sleeve) while maintaining a simple cylindrical shape elsewhere. The edge is formed such that all points on the edge are at a distance from the longitudinal axis greater than any other points on the sleeve outside in the common plane, creating a localized geometric feature that enables proper laser welding access and produces smooth weld seams meeting hygiene regulations.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If the sleeve edge is positioned close to the longitudinal axis for compact design, then the housing is compact, but laser welding cannot be properly performed

Engineering Contradiction:
Improvelaser welding feasibilityVSAvoidsleeve volume
Core Design Contradiction:
Ease of manufactureVSVolume of moving object

Solution Approach 1:

The patent resolves the spatial conflict by utilizing the radial dimension strategically. The edge configuration extends further from the longitudinal axis in the radial direction at the second end section, creating sufficient clearance for laser beam access without increasing the overall length or compromising compactness in other dimensions. This dimensional approach allows the laser welding process to be performed effectively while maintaining a compact sleeve design.

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

3Reliability

If the sleeve has a complex edge configuration to meet hygiene regulations, then hygiene standards are met, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvehygiene complianceVSAvoidsleeve geometry complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs asymmetry in the edge configuration where the edge at the second end section has points positioned at greater distance from the longitudinal axis compared to other portions of the sleeve. This asymmetric geometric feature is specifically designed to create the necessary conditions for hygienic welding (smooth, seamless weld joints) while maintaining symmetry and simplicity in the main body of the sleeve, thus balancing hygiene compliance with manufacturing simplicity.

Inventive Principle:
Principle #4Asymmetry

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 design enables easy and efficient manufacturing of temperature sensor housings that meet hygiene regulations by ensuring a smooth, seamless weld and optimal laser welding conditions, enhancing the manufacturing process and product quality.

Implementation Method 1

the sleeve can be welded to the edge with a sensor holder by means of a material bond by means of a laser

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Data Source

PatentEP2455725B1Housing of a temperature sensor, in particular a thermal flow measuring device
Publication Date: 2020.12.02 ENDRESS HAUSER FLOWTEC AG
  • EP2455725B1 patent drawingFigure 1

AI summary

The housing (1) has a shell (3) including end sections (5, 6) and a longitudinal axle (7) that extends between the end sections. The shell includes an outer side (8) that borders the housing toward an environment. Distance from a point of an edge (11) terminating the outer side in a region of one of end sections to the longitudinal axle of the shell is 0.2 mm greater than distance of another point of the edge to the longitudinal axle of the shell, where the shell lies in a plane shared with the axle. Distance is projected on the axle from the former point in direction of the end section. An independent claim is also included for a method for manufacturing a thermal flow measuring device.