Syringe Plunger Three-Step Structure for Pressure Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional syringes apply excessive reaction pressure to the plunger when injecting viscous liquids or completing injections, leading to fatigue for medical staff and discomfort for patients, especially in Luer-lock type syringes with flat plunger ends that cause bottlenecks, making it difficult to fully discharge the injection liquid without effort.
Innovation Solution
A syringe with a plunger and tapered tube featuring a three-step structure where the plunger's outer diameter gradually narrows and intervals shorten, matching the tapered tube's inner grooves, which reduces reaction pressure by distributing it evenly, allowing smooth injection without residual liquid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flat plunger end is used in conventional syringes, then the plunger structure is simple and easy to manufacture, but excessive reaction pressure is applied to the plunger when injecting viscous liquids or completing injections, causing fatigue for medical staff and discomfort for patients
Solution Approach 1:
The plunger is divided into multiple sections with different diameters (first plunger section, second plunger section, third plunger section) corresponding to different regions of the barrel. This segmentation allows each section to interact with the barrel at different points, distributing the reaction pressure along the length of the plunger rather than concentrating it at a single flat end, thereby reducing the peak force felt by the operator.
Solution Approach 2:
Different portions of the plunger are given different diameters to create localized interaction zones. The first plunger section with larger diameter interacts with the first barrel region, the second section with intermediate diameter interacts with the second barrel region, and the third section with smaller diameter interacts with the third barrel region. This local variation in geometry distributes pressure across multiple locations along the plunger-barrel interface.
2Device complexity
If a flat plunger end is used, then the syringe structure is simple, but injection liquid remaining in the tapered tube cannot be discharged, leading to medicinal liquid wastage
Solution Approach 1:
The plunger is segmented into multiple sections that correspond to different regions of the barrel, including the tapered tube region. The third plunger section with its specific diameter is designed to interact with the tapered tube, enabling complete discharge of injection liquid through the injection needle without leaving residual liquid in the syringe.
Solution Approach 2:
The plunger geometry transitions from a simple flat end to a multi-sectional structure with varying diameters along the longitudinal dimension. This dimensional variation allows the plunger to effectively engage with different parts of the barrel and tapered tube, ensuring complete liquid discharge while maintaining structural integrity.
3Productivity
If the plunger reaches the front end of the barrel, then injection is completed, but the plunger is subjected to increasingly larger reaction pressure due to the bottleneck state at the injection needle
Solution Approach 1:
The plunger is divided into multiple sections that interact with the barrel at different positions. The third plunger section with its smaller diameter is specifically designed to interact with the tapered tube and injection needle region, distributing the bottleneck pressure across this section rather than concentrating it at a single point, thereby reducing the peak reaction force during injection completion.
Solution Approach 2:
The plunger diameter varies along its length, creating different interaction parameters at different positions. The first plunger section has a larger diameter for initial barrel interaction, the second section has intermediate dimensions, and the third section has a smaller diameter optimized for the tapered tube and injection needle interface. This parameter variation distributes pressure throughout the injection process.
Data Source
AI summary
A syringe with plunger reaction pressure reduction structure is proposed. The syringe includes: a barrel including a finger grip at a rear end thereof and a Luer-lock connector in which a thread portion is formed on an inner surface outside a tapered tube of a front discharge end thereof; a plunger rod configured to be inserted in an inside of the barrel and including a push end at a rear end thereof; a plunger coupled to a front end of the plunger rod; and a needle hub configured to be screwed with the Luer-lock connector and including an injection needle mounted to a front end thereof. The syringe is configured to have a three-step structure at the plunger in which intervals between steps are gradually shortened, so that the reaction pressure applied to the plunger is distributed and the injection is easily performed.