Indwelling Needle Hub Lateral Flow Path Design
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Solution Overview
Problem
Conventional indwelling needle devices with a double-needle structure face challenges in providing a sufficient flow rate due to the limited cross-sectional area of the opening for communication with the hub's lumen, which compromises the structural strength and bulkiness of the device.
Innovation Solution
The indwelling needle device incorporates a lateral penetration path in the hub that communicates with the lumen, along with engagement recesses and projections, to create a larger flow path cross-sectional area while maintaining stable and firm coupling of the hub's side walls, allowing the hub to be compact in size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the opening in the hub is made larger to increase flow rate, then the flow rate is improved, but the structural strength of the hub coupling is weakened
Solution Approach 1:
The patent divides the flow path into multiple segments: the lumen of the inner needle and the space between the hub and shield tube. This segmentation allows the opening in the hub to remain small for structural strength while the additional flow path segment compensates for the limited opening area, achieving sufficient overall flow rate without compromising hub coupling strength
Solution Approach 2:
The patent utilizes the radial dimension by creating a flow path in the space between the hub outer peripheral surface and the shield tube inner peripheral surface. This additional dimensional space provides an extra flow channel that increases total flow rate without requiring a larger opening in the hub, thus maintaining structural integrity
2Reliability
If a separate mechanism for housing the inner needle is added, then accidental puncture prevention is improved, but the device becomes bulkier
Solution Approach 1:
The patent merges the accidental puncture prevention function with the existing shield tube structure. The shield tube serves dual purposes: it acts as the outer protective structure and simultaneously houses the inner needle when retracted. This integration eliminates the need for separate housing mechanisms, preventing accidental punctures while maintaining a compact device size
Solution Approach 2:
The shield tube is designed to perform multiple functions: providing structural support, guiding the needles during insertion, and serving as a housing for the inner needle after retraction. This multi-functionality reduces the overall device complexity and size while ensuring reliable accidental puncture prevention
Data Source
AI summary
An indwelling needle device includes a shield tube with a flexible outer needle fixed at a front end, a hub movable in a lumen of the shield tube, an infusion tube attached to an end thereof, a rigid inner needle at a front end part of the hub and insertable into a lumen of the outer needle. A lateral penetration path penetrates to a lumen of the hub. A space is provided between an outer surface of the hub and an inner surface of the shield tube. A sealing section is on the outer surface of the hub. The outer peripheral surface of the hub forms engagement recesses. A rear-end-side engagement projection is on the inner surface of the shield tube and engages with the engagement recesses. Hub side walls, with a communication area opening, couple with the front end of the hub. The hub can be small in size.