Inverted Cone Probe Transition for Sensor Sealing Integrity

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Solution Overview

Problem

Conventional probe transitions in sensors for determining process variables in containers face challenges such as leakage, mechanical damage, and complex metalworking requirements, which affect sealing integrity and durability, especially in dynamic and hygienic applications.

Innovation Solution

The proposed solution involves an inverted cone element with a conical design, where the cone's base is oriented downwards, creating a sealing interface with sloping bearing surfaces and a ring welded to the probe for additional support, enhancing sealing and stability with minimal additional effort, and using PEEK for the cone element and metal for the housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a cutting edge is used to seal the probe to the cone, then sealing is achieved, but the probe diameter is significantly reduced creating a weak point prone to fatigue fracture

Engineering Contradiction:
Improvesealing integrityVSAvoidprobe strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent inverts the conventional sealing approach by placing the cutting edge on the cone element instead of on the probe. This reversal allows the probe to maintain its full diameter and structural integrity while the cone element absorbs the sealing function through its cutting edge that penetrates the PEEK material.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The cone element acts as an intermediary component between the probe and the housing. It provides a sealing interface through its cutting edge without requiring the probe itself to be modified with a cutting edge, thus preserving the probe's strength while achieving reliable sealing.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If disc springs are used to seal the cone to the housing, then sealing is achieved, but process pressure acts against the spring force reducing the sealing effect

Engineering Contradiction:
Improvesealing integrityVSAvoidprocess pressure
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The patent inverts the sealing mechanism by using a cutting edge on the cone element that actively penetrates the PEEK housing material, rather than relying on spring force to push the cone against the housing. This inversion makes the sealing effective even under high process pressure.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent converts the harmful effect of process pressure into a beneficial sealing mechanism. The cutting edge design allows process pressure to force the cone element's cutting edge deeper into the PEEK housing, enhancing the sealing effect rather than reducing it.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If a conventional probe transition design is used, then connection is achieved, but complex metalworking and precise manufacturing are required

Engineering Contradiction:
Improveconnection stabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the material parameter of the cone element to PEEK, a thermoplastic that can be manufactured using molding processes rather than complex metalworking. This parameter change from metal to plastic simplifies manufacturing while maintaining connection stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite design where the cone element is made of PEEK and the housing is made of metal. This combination allows the PEEK cone to be manufactured with simpler processes while the metal housing provides structural strength, reducing overall manufacturing complexity.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3693712B1Sensor for determining a process variable
Publication Date: 2021.03.10 SICK AG
  • EP3693712B1 patent drawingFigure 1~2
  • EP3693712B1 patent drawingFigure 3~5
  • EP3693712B1 patent drawingFigure 6

AI summary

A sensor (10) for determining a process variable in a container (12) is described, comprising an elongated probe (16) for immersion in a medium (14) in the container (12), a control and evaluation unit (24) for measuring the process variable by means of the probe (16), and a housing (22) with a connection area for connecting an upper end of the probe (16) to the housing (22), wherein the connection area rests with an inclined bearing surface (32) on a conical element (26) arranged in the connection area. The base of the conical element (26) is oriented downwards towards the lower end of the probe (16).