Sealable Joint Structure for Fluid Sealing Under Vibration Loads
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Solution Overview
Problem
Existing sealable joints in medical devices, such as medicament delivery devices, are prone to failure under conditions like creep, aging, vibration, pressure loading, axial loading, transverse loading, and shock loading, leading to compromised fluidic sealing and mechanical retention.
Innovation Solution
A sealable joint design featuring a first component with a bore, a second component with a more resilient material and radially inwardly projecting members, and a third component with a sealing surface, forming an annular recess and interference fit to ensure fluid flow and mechanical retention, even under adverse conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a compression fitting with outer compression nut and inner compression ring is used, then mechanical linkage is provided, but the fluidic seal may fail under creep, aging, vibration, pressure loading, axial loading, transverse loading, and shock loading
Solution Approach 1:
The sealable joint is divided into three distinct components: a first component (male connector) with a stem and flanges, a second component (intermediate element) with radially inwardly projecting members, and a third component (female connector) with a sealing surface. This segmentation allows each component to perform its specific function optimally while working together to provide reliable sealing and mechanical linkage.
Solution Approach 2:
The second component with radially inwardly projecting members is nested within the annular recess formed by the first and third components. The radially inwardly projecting members are received within the annular recess between the first flange and second flange, creating a nested structure that provides both sealing and mechanical retention.
2Reliability
If the second component comprises a more resilient material, then sealing capability is improved, but mechanical strength may be reduced
Solution Approach 1:
The second component is made of a more resilient material specifically at the region where sealing contact occurs, allowing it to deform and conform to the sealing surface. This localized resilience provides effective sealing while the overall structure maintains adequate mechanical strength through the combination of all three components.
Solution Approach 2:
The sealable joint uses a combination of materials with different properties: the first and third components provide structural strength, while the second component uses a more resilient material for sealing. This composite approach allows each material to contribute its optimal properties to the overall system performance.
3Reliability
If the one or more radially inwardly projecting members are disposed in the annular recess, then mechanical retention is improved, but assembly complexity increases
Solution Approach 1:
The radially inwardly projecting members are pre-formed on the second component during manufacturing, and the annular recess is pre-formed on the first and third components. This preliminary preparation allows for straightforward assembly by simply bringing the components together, with the radially inwardly projecting members automatically engaging in the annular recess without requiring additional assembly steps.
4Productivity
If the outer surface of the second flange narrows relative to the longitudinal axis, then fluid flow control is improved, but manufacturing precision requirements increase
Solution Approach 1:
The outer surface of the second flange features a narrowed portion with a curved or tapered profile rather than a sharp transition. This curved geometry provides effective fluid flow control by creating a gradual transition zone, while being more tolerant of manufacturing variations compared to sharp edges or precise dimensional features.
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 design provides a robust mechanical connection and fluidic seal that maintains integrity under various loads, including vibration and pressure, while preventing incorrect assembly and allowing for efficient propellant dispensing in autoinjector sub-assemblies.
Implementation Method 1
at least part of the first flange deforms against the sealing surface
Implementation Method 2
the one or more radially inwardly projecting members comprise a plurality of radially flexible fingers
Implementation Method 3
abutment between the abutment surface and the one or more radially inwardly projecting members may limit axial movement of the second flange relative to the third component
Data Source
AI summary
A sealable joint including a first component, a second component, and a third component. The first component includes a stem having a bore therethrough for the passage of a fluid. The second component is disposed on the first component, and the third component includes a sealing surface and one or more radially inwardly projecting members. One of the second component and the first component, or a combination of the second component and the first component includes a first flange and a second flange that defines an annular recess therebetween. In a sealing configuration, the second component is received by the third component to form a sealed joint in which at least part of the first flange deforms against the sealing surface, the one or more radially inwardly projecting members are disposed in the annular recess between the first flange and the second flange.