Vascular Stent Delivery Inner Cannula Scratching Prevention
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Solution Overview
Problem
Existing vascular stent delivery systems face issues with reduced service life due to scratching between components, liquid leakage at connections, and poor flexibility, especially when navigating intensely curved lesion sites.
Innovation Solution
The vascular stent delivery system incorporates a modified inner cannula with a heat shrink tube to prevent scratching and an integrally formed cleaning tube made of polycarbonate to reduce leakage, along with a driving assembly that enhances axial movement and flexibility, using a rubber head and three-way tube configuration for improved operability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a middle steel tube is used in the cleaning tube assembly, then cleaning functionality is provided, but the inner cannula scratches the cleaning tube cavity wall due to relative movement
Solution Approach 1:
A protective coating layer is applied to the inner wall of the cleaning tube cavity to serve as an intermediary between the inner cannula and the cleaning tube. This coating prevents direct contact and scratching while allowing the cleaning tube to fulfill its cleaning function. The coating acts as a sacrificial layer that protects the underlying cleaning tube structure from damage caused by relative movement during operation.
2Ease of manufacture
If multiple connections are made in the cleaning pipeline, then cleaning functionality is achieved, but liquid leakage occurs at connection sites
Solution Approach 1:
The cleaning tube is designed as an integrally formed single-piece structure rather than an assembly of multiple connected segments. This merging of multiple connection points into a single continuous structure eliminates the connection sites where liquid leakage would occur, while still providing the necessary cleaning pipeline functionality through the integrated design.
3Strength
If the tubing assembly is made rigid for structural integrity, then strength is improved, but flexibility to navigate curved lesion sites deteriorates
Solution Approach 1:
The tubing assembly employs local quality variations through segmented construction with different stiffness characteristics in different sections. The proximal section maintains higher rigidity for structural integrity and control, while the distal section incorporates enhanced flexibility with a larger bending radius capability. This allows the tubing to maintain overall strength while adapting to curved anatomical paths during navigation.
4Device complexity
If the cone tip is directly adhered to the inner cannula, then assembly simplicity is achieved, but joint intensity is limited causing accidental detachment risk
Solution Approach 1:
The connection between the cone tip and inner cannula utilizes composite material construction with a multi-layered joint structure. This includes adhesive bonding combined with mechanical interlocking features, creating a composite joint that achieves high joint intensity while maintaining relatively simple assembly procedures. The composite approach combines the strengths of different joining methods to overcome the limitations of direct adhesion alone.
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 enhances the service life and reliability of the delivery system by preventing scratching and leakage, improving flexibility and operability, allowing for more effective deployment of stents in vascular procedures.
Implementation Method 1
The portion of the inner cannula within the cleaning tube is modified to prevent it from scratching the cleaning tube cavity's inner wall
Implementation Method 2
An integrally formed cleaning tube made of polycarbonate to reduce leakage
Data Source
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AI summary
A vascular stent conveying system includes a housing (110, 120), an outer cannula (200), a cleaning tube (300), an inner cannula (800), and a driving assembly (400). The outer cannula (200) is located outside the housing (110, 120) and is connected to a first end (101) of the housing (110, 120). The cleaning tube (300) is connected to a second end (102) of the housing (110, 120), a first end (301) of the cleaning tube (300) is located in the housing (110, 120), and a second end (302) of the cleaning tube (300) extends out of the housing (110, 120). A part of the inner cannula (800) is located in the housing (110, 120), a first end of the inner cannula (800) extends into the outer cannula (200), and a second end of the inner cannula (800) extends from the first end (301) of the cleaning tube (300) to a tube chamber of the cleaning tube (300). Apart of the driving assembly (400) is located in the housing (110, 120), and operably engaged with a part of the inner cannula (800) located in the housing (110, 120), so as to drive the inner cannula (800) to allow the inner cannula (800) to move along an axial direction in the outer cannula (200) and the cleaning tube (300). An end portion of the second end of the inner cannula (800) is arranged in a way for preventing the end portion of the second end of the inner cannula (800) from scraping the inner wall of the tube chamber of the cleaning tube (300).