Endoscope Shaft Flexible Membrane Sealing

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Solution Overview

Problem

Existing endoscopes face challenges in maintaining a permanent fluid-tight seal during thermal expansion and contraction of the outer and inner tubes under extreme temperature conditions, leading to potential contamination during cleaning.

Innovation Solution

The use of a flexible membrane to enable relative axial movement between the outer and inner tubes, ensuring a permanent fluid-tight connection, with options for the membrane to be connected between the tubes or housing parts, and incorporating additional sealing elements like O-rings to prevent moisture and dirt ingress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If O-rings are used to enable axial relative movement between outer tube and inner tube, then thermal length compensation is achieved, but fluid-tight sealing is not permanent under high thermal load

Engineering Contradiction:
Improvethermal length compensationVSAvoidfluid-tight sealing
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces the traditional O-ring sealing solution with a flexible membrane that spans between the outer tube and inner tube. This membrane maintains fluid-tight sealing while allowing thermal expansion and contraction of the tubes relative to each other, thus resolving the contradiction between sealing reliability and thermal adaptability

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention uses a composite structure combining the flexible membrane with additional sealing elements (O-rings) at strategic locations. This composite approach leverages the thermal flexibility of the membrane while the O-rings provide supplemental sealing, achieving both thermal compensation and permanent fluid-tight sealing under high thermal load

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If outer tube and inner tube are rigidly connected, then structural stability is maintained, but thermal expansion stresses cause contamination

Engineering Contradiction:
Improvestructural stabilityVSAvoidcontamination
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent transforms the rigid connection between outer tube and inner tube into a dynamic, flexible connection using a membrane. This allows the tubes to move relative to each other in response to thermal expansion, maintaining structural stability while preventing contamination caused by thermal stresses

Inventive Principle:
Principle #15Dynamics

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

This solution ensures a permanently fluid-tight relative movement of the tubes, maintaining sterility and preventing contamination, even under high thermal loads, while allowing for thermal expansion compensation.

Implementation Method 1

Due to different materials of the two tubes of the instrument shaft in conjunction with temperature fluctuations and/or due to different temperatures of the outer tube and inner tube, due to a delay in heat conduction from the outer tube to the inner tube, the outer tube and the inner tube expand differently under these, sometimes extreme, temperature loads

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

the outer tube and the inner tube are mounted on the instrument housing so that they can move relative to one another in the axial direction of the shaft by means of at least one flexible membrane

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2283767B1Endoscope
Publication Date: 2016.07.20 KARL STORZ SE & CO KG
  • EP2283767B1 patent drawingFigure 1
  • EP2283767B1 patent drawingFigure 2~3
  • EP2283767B1 patent drawingFigure 4~5

AI summary

The invention relates to an endoscope (1) with an instrument housing (2) and with a shaft (3) arranged at the distal end of the instrument housing (2), the shaft consisting of an outer tube (4) and an inner tube (5) arranged at least partially within the outer tube (4), wherein the outer tube (4) and the inner tube (5) are mounted on the instrument housing (2) so as to be movable relative to each other in the axial direction of the shaft (3). In order to create an endoscope (1) that ensures a permanently fluid-tight relative movement of the two shaft tubes (4, 5) relative to each other, the invention proposes that the axially movable mounting of the outer tube (4) and the inner tube (5) on the instrument housing (2) is effected by means of at least one flexible membrane (17).