Low Profile Venous Access Port Assembly Sealing
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Solution Overview
Problem
Existing venous access port assemblies lack assured security and sealing, particularly due to manufacturing tolerances causing gaps that compromise the integrity of the assembly and the bonding between components.
Innovation Solution
A venous access port design featuring a housing and septum with a mechanical snap-fit joint and solvent bonding, utilizing retention ribs and grooves, and crush ribs to center and secure the cap to the housing base, ensuring a secure and sealed connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ports are used with standard manufacturing tolerances, then assembly is simpler, but gaps and poor sealing occur between components
Solution Approach 1:
The patent applies beforehand cushioning by incorporating a compliant seal member (O-ring or gasket) between the cap and housing base. This seal member anticipates and compensates for manufacturing tolerance variations and assembly gaps, ensuring reliable sealing without requiring extremely tight manufacturing tolerances. The seal member deforms to fill gaps that would otherwise compromise sealing integrity.
Solution Approach 2:
The patent employs parameter changes by designing the cap and housing base with specific geometric features (flanges, recesses, interlocking elements) that control the assembly gap dimension. By carefully selecting and controlling the gap parameter within a specific range, the design accommodates manufacturing tolerances while maintaining effective sealing through the compliant seal member.
2Reliability
If retention ribs and grooves are added to secure the cap to the housing base, then assembly security improves, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the connection interface between cap and housing base into discrete functional elements: retention ribs on one component, corresponding grooves on the other, plus separate seal members. This segmentation allows each element to perform its specific function (mechanical retention, positioning, sealing) independently, achieving reliable assembly security through modular design.
Solution Approach 2:
The patent merges multiple functions into the cap-housing base connection system: retention ribs and grooves provide both mechanical retention and positioning alignment, while the integrated seal member provides sealing. This merging of retention, positioning, and sealing functions into a single connection interface achieves assembly security without proportionally increasing overall device complexity.
3Length of stationary object
If the port assembly height is reduced to create a low profile design, then patient comfort and implantability improve, but manufacturing and assembly precision requirements increase
Solution Approach 1:
The patent applies the nested doll principle by arranging components concentrically and nested within each other: the catheter hub is centered within the housing base, the seal member fits within the groove around the hub, and the cap encloses all these elements. This nested arrangement minimizes the radial and axial dimensions of the assembly, achieving low profile height while maintaining proper clearances and sealing through precise but achievable dimensional control.
Solution Approach 2:
The patent uses dimensionality change by transitioning from a conventional larger-diameter, shorter-height design to a smaller-diameter, optimized-height design. By reducing the radial dimension (diameter) of the port assembly, the overall volume and profile are reduced, allowing the height to be optimized for low profile implantability while maintaining adequate space for all functional components.
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 provides a secure, low-profile venous access port assembly with enhanced sealing and bonding, minimizing manufacturing tolerances' impact and eliminating the need for additional tooling fixtures, resulting in a reliable and efficient fluid communication system.
Implementation Method 1
During assembly of the cap to the housing base, the outer surface of the housing base crushes the crush ribs during the very final stages of the mechanical securing process; but the crush ribs serve to precisely center the housing base within the cap are within the incremental 'play' or gapping.
Implementation Method 2
Just prior to mechanical assembly, solvent is applied to several selected surfaces of the housing base exterior and the cap's interior, and the crush ribs facilitate solvent wicking to the surfaces of the interface, resulting in a superior bond between the cap and the housing base.
Data Source
AI summary
A venous access port assembly having a housing base with a discharge stem, a septum, and a cap. An interior reservoir is defined by a well in the housing base and the bottom surface of the septum, and a passageway extends from the reservoir through the discharge stem. The cap is secured to the housing base and securely retains the septum in the assembly, compressing an annular flange of the septum against a septum seat of the housing base. Horizontal ribs on the interior of the cap snap into complementary grooves on the side wall of the housing base to mechanically lock together the cap and housing base during curing of the solvent bonding agent. The cap is mechanically secured and bonded to the housing base. Crush ribs on the interior surface of the cap, precisely center the cap about the housing base during assembly and compensating for manufacturing tolerances.