Catheter Liner Assembly Using Local Heating for Secure Wall Contact
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Solution Overview
Problem
Existing lubricious liners in catheter tubes face challenges in securely attaching to the inner wall due to their non-stick properties, leading to partial or complete floating within the tube, resulting in a small contact area and potential stretching, which complicates assembly and movement.
Innovation Solution
A method is employed to radially expand and optionally join portions of the lubricious liner to the inner wall of the catheter tube, ensuring a consistent diameter match and secure attachment, using localized heating and expansion with a heat source and expander, allowing for both non-joined and joined sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a lubricious liner is inserted into the catheter to reduce friction, then the sliding of the object through the catheter is facilitated, but the liner is difficult to join to the inner wall of the catheter due to non-stick properties
Solution Approach 1:
The patent applies parameter changes by heating the liner to its melting point temperature (100°C to 200°C) to alter its physical state from solid to molten, enabling it to conform to and bond with the catheter wall. After cooling, the liner solidifies and adheres to the wall, resolving the non-stick issue while maintaining lubricious properties
Solution Approach 2:
The patent utilizes phase transitions of the liner material by heating it above its melting point to transform from solid to liquid state, allowing it to flow and adhere to the catheter inner wall. Upon cooling, it transitions back to solid state, creating a permanent bond while preserving the lubricious surface
2Device complexity
If the liner is made floating inside the tube to allow movement, then assembly is simplified, but the contact area between liner and tube is reduced and stretching occurs
Solution Approach 1:
The patent applies preliminary action by heating and expanding the liner before final assembly into the catheter. This pre-expansion ensures the liner achieves the correct diameter and conformal fit to the catheter inner wall, preventing stretching during subsequent assembly and operation while maintaining proper contact area
3Ease of manufacture
If the liner outer diameter is made smaller than the tube inner diameter to allow insertion, then assembly is easier, but the contact area is reduced and liner movement is allowed
Solution Approach 1:
The patent applies parameter changes by thermally expanding the liner after insertion. The heated liner expands radially outward to increase its outer diameter until it conforms to the tube inner diameter, maximizing contact area and eliminating excessive movement while maintaining ease of initial insertion
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 approach ensures a large contact area between the liner and tube, preventing stretching and enhancing stability, while allowing the tube to bend freely where unattached, thus improving assembly and movement efficiency.
Implementation Method 1
heating a portion of the liner, called a heated portion, with a local heat source
Implementation Method 2
a temperature to which the liner is heated is a temperature which softens the liner
Implementation Method 3
expanding the heated portion radially outwards so that the heated portion abuts against an inner wall of the tube
Implementation Method 4
the tube is joined to the liner by heating the tube to a temperature above a melting point of the liner
Data Source
AI summary
A method for assembling a liner in a tube includes placing a liner in a tube, and heating a portion of the liner, called a heated portion, with a local heat source. The heated portion is not more than a third of a total length of the liner. The heated portion is expanded radially outwards so that the heated portion abuts against an inner wall of the tube. The local heat source is repeatedly advanced longitudinally along a desired length of the liner to expand the heated portion radially outwards so that the heated portion abuts against the inner wall of the tube for the desired length.