Retractable Fitting Sealing System for Sterile Medium Contamination

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Solution Overview

Problem

Existing retractable fittings in analytical measurement technology lack a reliable separation between the treatment chamber and the drive, leading to potential contamination of the process medium, which is critical in sterile environments, as unclean substances from the drive can enter the treatment chamber and contaminate the medium.

Innovation Solution

A retractable fitting with a housing, medium connection, and an immersion tube that can be axially moved between three positions, featuring a sealing system divided into three areas with a locking element or self-locking drive to prevent contamination exchange between the drive and treatment chamber, and a detection system to monitor seal integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a retractable fitting is used with a drive mechanism to move the immersion tube, then the probe can be positioned and retracted automatically, but unclean substances from the drive can enter the treatment chamber and contaminate the sterile medium

Engineering Contradiction:
Improveautomatic positioning of probeVSAvoidcontamination of sterile medium
Core Design Contradiction:
Extent of automationVSObject-affected harmful factors

Solution Approach 1:

The immersion tube is divided into three distinct areas: an upper area facing away from the container, a middle area with the sealing system, and a lower area facing the container. This segmentation creates isolated zones that prevent contamination spread while maintaining automated operation capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A sealing system is introduced as an intermediary element between the drive mechanism and the treatment chamber. This sealing system acts as a barrier that prevents direct contact between potentially contaminated drive substances and the sterile medium, while still allowing the drive to function.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the sealing system is made more robust to prevent contamination, then medium safety is improved, but the complexity of the device increases

Engineering Contradiction:
Improvesealing integrityVSAvoidstructure of retractable fitting
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sealing system is divided into three sections corresponding to the three areas of the immersion tube. This segmentation allows the sealing function to be distributed and managed in discrete units, making the overall system more manageable despite the added complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sealing system serves multiple functions simultaneously: it prevents contamination, enables cleaning access, and maintains pressure differentials. By designing the sealing system to fulfill multiple roles, the need for additional separate components is reduced.

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

3Object-affected harmful factors

If the immersion tube is divided into three areas with a sealing system, then contamination prevention is improved, but the device complexity increases

Engineering Contradiction:
Improvecontamination preventionVSAvoidstructure of immersion tube
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The immersion tube is explicitly divided into three areas with the sealing system in the middle area. This segmentation creates clear boundaries that prevent contamination while organizing the complexity into manageable, functionally distinct sections.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2557417B1Replacement fitting
Publication Date: 2016.05.11 ENDRESS HAUSER CONDUCTA GMBH CO KG
  • EP2557417B1 patent drawingFigure 1a
  • EP2557417B1 patent drawingFigure 1b
  • EP2557417B1 patent drawingFigure 1c

AI summary

The invention relates to a changeover fitting comprising a housing (2), a medium connection (7) with complementary connection means (8) arranged on the housing (2) and making the changeover fitting connectable to a container (1) filled with medium (5), a dip tube (10) which is axially movable by a drive (9) at least between two, preferably three positions, namely a process position extended from the housing (2), at least one intermediate position, and a service position retracted into the housing (2), a probe (4) provided in the dip tube (10), wherein the probe (4) has a probe head (6) at its end facing the medium (5), wherein in the service position the probe head (6) is arranged within a treatment chamber (3) formed in the housing (2), wherein the dip tube (10) is divided into three areas, namely an upper area (11) facing away from the container,a middle area (12) on which a sealing system (20) is provided, and a lower area (13) facing the container, wherein the sealing system (20) is designed such that in no position of the immersion tube (10) is there an exchange of medium (5) or impurities from the drive (9) to the treatment chamber (3) and vice versa.