Capillary Connection Sleeve Structure for High-Pressure Sealing
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Solution Overview
Problem
Existing capillary connection units for analysis and medical devices face challenges in maintaining a secure seal, especially under high-pressure conditions, and often require frequent tightening due to material flowability, which can lead to reduced tightness and potential sealing element displacement into dead spaces or capillary channel narrowing.
Innovation Solution
A capillary connection unit design featuring a metallic sleeve element that is axially displaceable relative to the connection element and capillary, with a sealing element that is radially compressed inwardly against the capillary and outwardly against the sleeve, ensuring optimal sealing without radial movement and allowing for easy inspection of damaged seals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing element is pressed against the opposing wall with high contact force by screwing the capillary connector element and mating element together, then the sealing performance is improved, but the sealing element may be crushed into the capillary channel or reduce the capillary channel size
Solution Approach 1:
The sealing element is divided into multiple independent sealing lips (first sealing lip, second sealing lip, third sealing lip) that can deform independently. This segmentation allows each lip to distribute the contact force more evenly, preventing any single point from crushing into the capillary channel while maintaining overall sealing effectiveness.
Solution Approach 2:
Different regions of the sealing element have different geometric configurations optimized for their specific functions. The first sealing lip has a specific profile for sealing against the capillary inner wall, the second sealing lip has a different profile for sealing against the capillary outer wall, and the third sealing lip has yet another profile for sealing against the mating element. This local optimization ensures effective sealing without excessive force concentration that could narrow the capillary channel.
2Reliability
If the sealing element is made of flowable material like PEEK to achieve tight seal, then the sealing performance is improved, but the connection must be tightened regularly otherwise the circumferential tightness will deteriorate
Solution Approach 1:
The sealing element is designed to be axially displaceable within the connection element, allowing it to dynamically adjust its position and sealing contact force in response to pressure changes and material flow. This dynamic capability enables the sealing element to maintain tightness over time without requiring regular manual tightening, as it can self-adjust to compensate for material flow and settling.
Solution Approach 2:
The sealing element's design allows it to self-regulate its sealing performance through axial displacement and deformation. The multi-lip structure enables each sealing lip to independently adjust its contact pressure, and the axial displaceability allows the entire element to move to maintain optimal sealing contact. This self-service mechanism eliminates the need for regular maintenance tightening.
3Reliability
If the sealing element is allowed to expand circumferentially to achieve tight seal, then the sealing performance is improved, but the sealing element may escape into dead spaces in the tolerance zones of the sealing area
Solution Approach 1:
The sealing element is segmented into multiple controlled expansion zones corresponding to different sealing lips. Each sealing lip is designed to expand circumferentially in a controlled manner at its specific sealing location, rather than as a single unified expansion. This segmentation prevents uncontrolled displacement into dead spaces while maintaining sealing effectiveness at each interface.
Solution Approach 2:
Different sealing lips have different geometric profiles and material properties optimized for their specific sealing locations. The first sealing lip is configured for sealing against the capillary inner wall with specific expansion characteristics, the second sealing lip has different characteristics for sealing against the capillary outer wall, and the third sealing lip has yet another configuration for sealing against the mating element. This local optimization ensures controlled circumferential expansion at each sealing point without displacement into dead spaces.
4Reliability
If a metallic sleeve element is introduced to surround the sealing element, then the sealing element is protected from displacement, but the device complexity increases
Solution Approach 1:
The metallic sleeve element is integrated with the connection element as a single component, with the sleeve forming an integral part of the connection element's structure. This merging eliminates the need for separate assembly steps and reduces the number of discrete parts, thereby minimizing the increase in device complexity while still providing the protective function of preventing sealing element displacement.
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 design provides a secure, low-maintenance seal under high-pressure conditions, preventing sealing element displacement and maintaining tightness by distributing material displacement over a larger area, while allowing for easy identification and replacement of damaged units.
Implementation Method 1
the sealing element is radially compressed inwardly against the capillary and outwardly against the sleeve
Implementation Method 2
the connection element with the free end of the capillary is designed to be detachably connected to a counter element and to exert an axial thrust force on the sealing element
Data Source
Figure 1~3
Figure 4~5
Figure 6
AI summary
The invention relates to a capillary connection unit for analysis devices and medical devices, comprising a capillary (20) having at least one end section (23) and a free end (24) thereon, comprising at least one connection element (11) arranged on the end section (23) of the capillary (20), wherein the connection element (11) has an axial guide-through (12) for the capillary (20), comprising a sealing element (13) surrounding the capillary (20), and comprising a metal sleeve element (14) which radially externally surrounds the sealing element (13) and which has a first end (14.1) facing the connection element (11) and a receiving region (14.3) facing away from the connection element (11), wherein the connection element (11) is configured to be detachably connected to a counter element (30) and to exert an axial thrust force (F) onto the sealing element (13). The sleeve element (14) is guided such that it is axially moveable with the sealing element (13) in relation to the connection element (11) and in relation to the capillary (20), and the inner diameter of the sleeve element (14) is at least as large in the receiving region (14.3) as the outer diameter of the sealing element (13) in order to accommodate the sealing element (13) substantially entirely in the receiving region (14.3) thereof. The sleeve element (14) has a first thrust surface (15.1) on the first end (14.1) thereof for receiving the thrust force (F) of the connection element (11) and a radially internal second thrust surface (15.2) facing the sealing element (13) on the end (14.2) of the sleeve element facing away from the connection element (11) for forwarding the thrust force (F) to the sealing element (13).