SMP Junctions for IV Tubing Pull-Out Force
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Solution Overview
Problem
Infusion or IV sets face challenges with weak junctions between tubing and components, leading to low pull-out force and burst pressure, resulting in leaks and separations due to design and assembly process shortfalls.
Innovation Solution
The use of shape memory polymer (SMP) connectors that change states in response to external stimuli such as temperature or moisture, providing a strong and consistent connection by expanding or contracting to securely engage IV tubes with components, enhancing friction fit and bond strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional solvent bonding or retaining rings are used to join IV tubing and components, then the junction can be formed, but the pull-out force and burst pressure are low causing leaks and separations
Solution Approach 1:
The patent applies parameter changes by utilizing temperature-induced dimensional changes in the SMP ring. The ring is designed to expand when exposed to elevated temperatures (such as during autoclaving) and contract when cooled, thereby dynamically adjusting the bonding pressure and maintaining junction reliability under varying operational conditions.
Solution Approach 2:
The patent employs phase transitions of the shape memory polymer material, which undergoes a phase change between expanded and contracted states in response to temperature variations. This phase transition mechanism enables the SMP ring to provide consistent bonding force across different storage and usage conditions, significantly improving pull-out force and burst pressure.
2Force
If traditional retaining rings are crimped or crushed to secure tubing, then the junction is retained, but the degree of retaining force varies significantly due to design and assembly shortfalls
Solution Approach 1:
The SMP ring provides self-service by automatically adjusting its retaining force through temperature-responsive dimensional changes. The ring expands during assembly to facilitate easy installation and then contracts to provide consistent retaining force, eliminating the need for precise manual crimping or crushing operations and ensuring uniform bonding pressure.
Solution Approach 2:
The patent introduces dynamics by using a material that actively changes its physical state in response to environmental conditions. The SMP ring transitions between expanded and contracted states based on temperature, providing adaptive retaining force that maintains consistency despite variations in assembly conditions or storage temperature.
3Reliability
If the SMP ring is in contracted state for retention, then the junction is secure, but the ring cannot be easily installed on the tubing
Solution Approach 1:
The SMP ring exhibits dynamic dimensional changes in response to temperature. During installation, the ring is exposed to elevated temperatures (such as body temperature or ambient heat) causing it to expand and slip over the tubing easily. Once installed and cooled, the ring contracts to provide secure retention, thus achieving both ease of installation and junction security.
Solution Approach 2:
The patent utilizes parameter changes by designing the SMP ring to undergo dimensional expansion when exposed to higher temperatures during installation, and then contract when cooled during use. This temperature-driven parameter change enables the ring to transition from an easy-to-install expanded state to a secure-retention contracted state.
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 SMP connectors significantly increase the pull-out force and burst pressure of the junctions, minimizing leaks and separations, and providing a more reliable connection between IV tubes and components.
Implementation Method 1
an SMP ring formed of a shape changing material... The shape changing material is configured to change to one of the expanded state and the contracted state upon being subjected to an external stimuli
Implementation Method 2
the SMP ring has an expanded state in which the SMP ring is slideably disposed encircling the connector/tube junction and a contracted state in which the SMP ring is retained in a retaining position squeezing the connector/tube junction. The external stimuli is a change in temperature
Implementation Method 3
the spigot is sized and shaped to provide a friction fit with the inner surface of the IV tube
Implementation Method 4
The junctions are typically formed by applying a thin layer of solvent or adhesive on one or both of the contacting surfaces and then the two surfaces are brought together
Data Source
AI summary
Junction assemblies for joining intravenous (IV) devices to tubing are provided. A junction assembly includes a component connector and a shaped memory polymer (SMP) member formed of a shape changing material. The junction assembly allows movement of the tube along the component connector when the SMP member is in an expanded state and the junction assembly retains the tube securely against the component connector when the SMP member is in a contracted state. The shape changing material changes to one of the expanded state and the contracted state upon being subjected to an external stimuli. Methods of assembling junction assemblies are also provided.