Endoscope Flexible Cladding Tube for Steam Sterilization Protection

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Solution Overview

Problem

Endoscopes face challenges in protecting the image guide from mechanical damage and steam ingress during sterilization, particularly at bends, which can lead to image degradation and equipment failure.

Innovation Solution

The endoscope design incorporates a flexible, vapor-tight cladding tube surrounding the image guide, made from materials like NiTi alloys or PEEK, to prevent friction damage and steam ingress, with a metal bellows allowing bending while maintaining structural integrity and vapor-tightness, and a joint enabling controlled angulation to reduce stress on the cladding tube.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the image guide is routed through a joint allowing angulation, then the eyepiece can be positioned optimally for viewing, but the image guide is exposed to mechanical damage from friction and steam ingress

Engineering Contradiction:
Improveeyepiece positioningVSAvoidimage guide protection
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The image guide is nested within a protective cladding tube that extends through the joint area. The cladding tube acts as a protective sleeve surrounding the image guide, allowing the joint to articulate while the image guide remains shielded from mechanical damage and steam exposure.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The cladding tube serves as an intermediary protective layer between the image guide and the harsh environment (steam and mechanical friction). It mediates the protection function, allowing the image guide to maintain its delicate structure while enabling joint movement for eyepiece positioning.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If a rigid protective structure is used around the image guide, then mechanical protection is improved, but flexibility and ability to accommodate joint movement is reduced

Engineering Contradiction:
Improvemechanical protectionVSAvoidflexibility for joint movement
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The cladding tube is designed with flexible material properties that allow it to bend and articulate with the joint movement while maintaining its protective function. This flexible shell provides mechanical protection without constraining the necessary movements for eyepiece positioning and shaft articulation.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The cladding tube is designed to dynamically adapt to joint movements rather than resisting them. It flexes and deforms elastically to accommodate the articulation of the joint, maintaining protection while allowing the system to achieve various viewing angles through eyepiece positioning.

Inventive Principle:
Principle #15Dynamics

3Stability of the object's composition

If the cladding tube is made rigid to prevent deformation, then structural integrity is improved, but friction damage to the image guide increases during bending

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

Solution Approach 1:

The cladding tube uses a flexible design that allows it to bend smoothly during joint articulation, preventing the image guide from contacting rough or corrugated surfaces that would cause friction damage. The flexibility ensures the tube maintains structural integrity while accommodating movement without creating harmful friction.

Inventive Principle:
Principle #30Flexible shells and thin films

4Reliability

If superheated steam sterilization is applied, then sterilization effectiveness is improved, but steam ingress can cause glass corrosion and fogging of optical elements

Engineering Contradiction:
Improvesterilization effectivenessVSAvoidsteam ingress damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The image guide is nested within the cladding tube that provides a protective barrier against steam ingress. This nested structure allows the entire assembly to undergo superheated steam sterilization externally while the cladding tube prevents steam from reaching and damaging the optical elements and glass components of the image guide.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The cladding tube acts as an intermediary barrier between the superheated steam environment and the sensitive optical components. It allows the sterilization process to proceed effectively on the external surface while preventing steam penetration that would cause glass corrosion and optical element fogging.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design effectively protects the image guide from mechanical damage and steam ingress, ensuring reliable image transmission and extended equipment lifespan by minimizing deformation and friction, while allowing flexible angulation for optimal insertion and handling.

Implementation Method 1

protecting the image guide from damage caused by friction during the bend, for example by friction with the inside of a metal bellows surrounding the image guide

Methodology Applied
Scientific EffectFriction reduction: Lubrication

Implementation Method 2

a flexible metal bellows, which is attached in a vapour-tight manner to the proximal end piece and distally to the proximal end of the enveloping tube

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

image conductors are usually sensitive to hot steam, which penetrates during superheated steam sterilization and can lead to glass corrosion, for example

Methodology Applied
Scientific EffectVapor barrier: Permeation

Implementation Method 4

a flexible or semi-flexible image guide is used in generic endoscopes, which usually consists of a bundle of optical fibers

Methodology Applied
Scientific EffectOptical fiber transmission: Optical Fibre

Data Source

PatentEP2253265B1Endoscope
Publication Date: 2013.04.10 KARL STORZ SE & CO KG
  • EP2253265B1 patent drawingFigure 1
  • EP2253265B1 patent drawingFigure 2~3
  • EP2253265B1 patent drawingFigure 4~5

AI summary

An endoscope, particularly for the intubation of an airway, comprises a shaft (2) having a lens in its distal end region (4) for capturing an endoscopic image, and an endoscope head (3) comprising a first head section (10) connected to the shaft (2) and a second head section (20) having an eyepiece, wherein the second head section (20) is articulated relative to the first head section (10), and wherein the endoscope includes an image guide (53) that is at least partially flexible for transmitting the image captured by the lens to the eyepiece. According to the invention, the image guide (53) is surrounded by a sheath tube (50) extending from the shaft to the second head section, which is at least partially flexible. This provides protection against both mechanical damage and the ingress of steam during steam sterilization.