Protruding Temperature Sensor Tip With Vacuum-Soldered Sealing

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Solution Overview

Problem

Existing temperature sensor devices often suffer from a trade-off between measurement accuracy and durability, as they are often bulky and slow to respond due to protective tubes that provide thermal resistance, leading to delayed temperature detection in process media.

Innovation Solution

A temperature sensor device with a support tube that allows the sensor element to extend beyond its distal end, sealed with soldered connections, and uses vacuum soldering to ensure reliable and leak-proof connections, reducing thermal decoupling and enhancing measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a protective tube is used to shield the sensor element, then the sensor element is protected from damage and interference, but the protective tube presents greater thermal resistance causing longer response time

Engineering Contradiction:
Improvesensor element protectionVSAvoidresponse time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The sensor element is extracted from the protective tube at the distal end, allowing it to protrude beyond the tube opening. This enables direct contact with the process medium while the protective tube still provides shielding along its length, resolving the contradiction between protection and fast response time.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The protective tube is segmented into two functional zones: a protected zone where the sensor element is enclosed within the tube, and an exposed zone where the sensor element protrudes beyond the distal end. This segmentation allows simultaneous achievement of protection and fast thermal response.

Inventive Principle:
Principle #1Segmentation

2Loss of time

If the sensor element protrudes beyond the protective tube to reduce thermal resistance, then response time is reduced, but the connection between sensor element and protective tube may be compromised

Engineering Contradiction:
Improveresponse timeVSAvoidconnection reliability
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The connection method is changed from mechanical or adhesive bonding to vacuum soldering, which creates a metallurgical bond with superior strength and hermetic sealing. This parameter change in the joining process ensures reliable connection even when the sensor element protrudes beyond the protective tube.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Vacuum soldering is performed in a vacuum environment, which prevents oxidation and contamination during the soldering process. This inert environment ensures high-quality, reliable connections between the sensor element and protective tube, maintaining connection reliability while allowing sensor protrusion.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

3Ease of manufacture

If conventional soldering is used to connect the sensor element, then the manufacturing process is simple, but the connection may not be sufficiently leak-proof for process media

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidleak-proof connection
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The soldering process is performed in a vacuum environment rather than atmospheric conditions. This vacuum environment prevents oxidation of the solder joint and eliminates air bubbles, creating hermetic, leak-proof connections that are reliable for process media applications.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The soldering process parameters are changed by performing soldering in vacuum conditions with controlled temperature and atmosphere. This parameter change transforms conventional soldering into vacuum soldering, which produces superior leak-proof connections while maintaining manufacturing feasibility.

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

The solution provides fast response times and high measurement accuracy with increased reliability and safety, while maintaining cost-effectiveness and reducing the risk of process medium leakage.

Implementation Method 1

The support tube (110) is sealedly connected to the first sensor element (120) by soldered connections (150, 150') at the first and second mounting areas (130, 140).

Methodology Applied
Scientific EffectSoldering: Soldering

Implementation Method 2

uses vacuum soldering to ensure reliable and leak-proof connections

Methodology Applied
Scientific EffectVacuum soldering: Soldering

Implementation Method 3

at least one temperature sensor is brought directly to or near the measuring tip and arranged within the sheathed cable. This temperature sensor is, for example, a resistance thermometer, e.g., a platinum resistance thermometer, or a junction of a thermocouple.

Methodology Applied
Scientific EffectTemperature sensing: Thermocouple

Implementation Method 4

The sheathed cable is made of stainless steel, for example, and filled with a mineral powder to insulate the sensor wires running inside it

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP4283268B1Temperature sensing device
Publication Date: 2025.12.10 WIKA ALEXANDER WIEGAND SE & CO KG
  • EP4283268B1 patent drawingFigure 1
  • EP4283268B1 patent drawingFigure 2A~3B
  • EP4283268B1 patent drawingFigure 4A~5B

AI summary

The invention relates to a temperature sensor device (100) comprising a support tube (110) with a distal end (111) having a first distal opening (112), a proximal end (113) with a first proximal opening (114), and a channel (115) extending between the openings (112, 114). The temperature sensor device (100) further comprises a sensor element (120) which is inserted into the channel (115) through the first proximal opening (114) and passes through it, such that a measuring tip (121) of the sensor element (120) passes through the first distal opening (112) and projects at least partially beyond the distal end (111) of the support tube (110). According to the invention, the support tube (110) has a first fastening area (130) at or near the distal end (111) and a second fastening area (140) at or near the proximal end (113).The sensor element (120) is connected to the support tube (110) by soldered connections (150, 150') at the first and second mounting areas (130, 140) either directly or indirectly.