Elastic Cap Body Radial Compression Sealing for Syringe Leakage
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Solution Overview
Problem
Existing syringes face issues with drug solution leakage due to adherence to the inner surface of the female luer section, leading to loose engagement with male luer sections and potential leakage, especially during freeze-drying processes where thermal conductivity and drying efficiency differ between the cylindrical and body portions.
Innovation Solution
A syringe design featuring a cap body made of elastic material with specific sealing sections that compress radially inward to create a liquid-tight seal, preventing drug solution adherence and leakage, and a cap configuration that includes a proximal-end protruding portion to direct internal pressure away from the cap, ensuring secure attachment and easy removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cap is inserted into the cylindrical portion without sealing sections, then the device complexity is reduced, but the drug solution adheres to the inner peripheral surface of the female luer section causing leakage
Solution Approach 1:
The cap body is divided into multiple functional sealing sections: a first sealing section with a first sealing surface that contacts the inner peripheral surface of the cylindrical portion, and a second sealing section with a second sealing surface that contacts the proximal end section of the cylindrical portion. This segmentation allows each section to address specific leakage pathways independently, preventing drug solution from adhering to the female luer section while maintaining a manageable structural complexity.
2Reliability
If the cap body is made of rigid material, then the structural strength is improved, but the sealing effectiveness is reduced due to inability to compress radially inward
Solution Approach 1:
The cap body is constructed from an elastic material that exhibits flexible deformation characteristics. This allows the cap body to compress radially inward when pressed against the cylindrical portion, enabling the sealing surfaces to conform to the inner peripheral surfaces and create liquid-tight seals. The elastic material maintains sufficient structural strength while providing the necessary flexibility for effective sealing during the freeze-drying process.
3Productivity
If the internal pressure of the body portion increases during freeze-drying, then the drying efficiency is improved, but the cap body may detach from the cylindrical portion
Solution Approach 1:
The cap body is designed with sealing sections that are preliminarily positioned to contact the inner peripheral surfaces of the cylindrical portion before the freeze-drying process begins. The first sealing section contacts the inner peripheral surface of the cylindrical portion, and the second sealing section contacts the proximal end section, creating pre-established sealing pathways that prevent drug solution leakage even when internal pressure increases during freeze-drying, thereby maintaining secure attachment.
4Ease of operation
If the cap body is designed with protruding portions to direct internal pressure, then the cap removal ease is improved, but the device complexity increases
Solution Approach 1:
The cap body incorporates asymmetric protruding portions that extend in the proximal direction from the base. These protruding portions are positioned to interact with the cylindrical portion in a non-symmetric arrangement, creating directional forces that facilitate easy cap removal when internal pressure builds up during freeze-drying. The asymmetric design provides intuitive removal characteristics while adding minimal structural complexity compared to symmetric alternatives.
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 effectively prevents drug solution leakage and adherence, maintains secure engagement between luer sections, and facilitates effective freeze-drying by ensuring the drug solution remains within the body portion, while allowing easy cap removal and reattachment.
Implementation Method 1
the first sealing section seals a distal end section of the flow path in a liquid-tight manner by being compressed radially inward by an inner peripheral surface constituting the opening of the cylindrical portion
Implementation Method 2
the second sealing section seals a proximal end section of the flow path in a liquid-tight manner by being compressed radially inward by an inner peripheral surface of the proximal end section of the cylindrical portion
Implementation Method 3
a cap body that is attached to the cylindrical portion and that is made of an elastic material
Data Source
AI summary
In a syringe, which is a prefilled syringe, when a cap body is attached to a cylindrical portion, a first sealing section is compressed radially inward by an inner peripheral surface constituting an opening of the cylindrical portion, thereby sealing a distal end section of a flow path in a liquid-tight manner, and a second sealing section is compressed radially inward by an inner peripheral surface of a proximal end section of the cylindrical portion, thereby sealing a proximal end section of the flow path in a liquid-tight manner.