Medicinal Liquid Pumping Apparatus Plunger Positioning
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Solution Overview
Problem
Conventional medicinal liquid injection apparatuses face issues with lubricant deformation, increased frictional resistance, cumbersome priming operations, and adhesion problems, which hinder consistent flow rates and efficient operation.
Innovation Solution
The medicinal liquid pumping apparatus features a chamber with a plunger and a pressing actuator, including a one-way valve and hydrophobic filter, allowing for controlled lubricant protection and simplified priming through additional medicinal liquid introduction to manage volume and pressure effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the plunger slides along the inner surface of the chamber during medicinal liquid filling, then the internal space can be expanded, but the lubricant applied to the inner surface is damaged or messily deformed
Solution Approach 1:
The plunger is pre-positioned at a predetermined location before medicinal liquid filling, such that the internal space has a predetermined volume. This preliminary positioning prevents the plunger from sliding along the inner surface during filling, thereby protecting the lubricant film from damage while still allowing sufficient internal space for the medicinal liquid
Solution Approach 2:
The chamber is designed with different functional zones: the internal space for medicinal liquid storage and the predetermined location of the plunger that acts as a boundary. By defining the plunger's position in advance rather than allowing free movement during filling, the system locally protects the lubricant film zone while maintaining the necessary volume for liquid storage
2Speed
If the plunger slides along the inner surface during contraction, then the medicinal liquid can be injected, but frictional resistance increases due to lubricant deformation
Solution Approach 1:
The plunger position is predetermined before the contraction process begins. This preliminary positioning ensures that the plunger starts from a known, optimized location that minimizes the sliding distance and frictional resistance during contraction, while still allowing sufficient space for the medicinal liquid to be injected at the required speed
3Reliability
If the plunger is placed at one position in the chamber for a considerable period, then the inner surface adheres to the plunger due to lubricant influence, but excessive pressure is required to move the plunger
Solution Approach 1:
The plunger is positioned at a predetermined location that is optimized to prevent adhesion. By carefully selecting this preliminary position, the system maintains stable plunger positioning (reliability) while avoiding the adhesion problem that would require excessive pressure to overcome. The predetermined position ensures the plunger is not stationary for too long at any one location
Solution Approach 2:
The system changes the positional parameter of the plunger to a predetermined location that balances two competing requirements: maintaining positioning stability to prevent adhesion, and minimizing the force required to move the plunger. This parameter optimization resolves the contradiction between reliability and movement ease
4Productivity
If a pressing actuator is used for priming operation, then liquid injection can be generated, but the operation becomes cumbersome
Solution Approach 1:
The filling and priming operations are merged into a single integrated process. The same medicinal liquid that fills the internal space is also used to perform the priming function by passing through the tube. This eliminates the need for separate priming operations with press actuators, maintaining injection capability while greatly simplifying the operation
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 solution minimizes lubricant damage, ensures constant frictional force, facilitates easy priming, and enables consistent medicinal liquid injection without excessive pressure, improving operational efficiency and flow rate stability.
Implementation Method 1
a vent hole (110c) and a hydrophobic filter (118) configured to allow passage of air discharged from the internal space (110s) to the outside through the vent hole (110c) and block passage of a liquid
Implementation Method 2
a one-way valve disposed in the inflow port and configured to allow a flow of the medicinal liquid moving from an outside to the internal space and block a flow of the medicinal liquid moving from the internal space to the outside
Implementation Method 3
a plunger (120) disposed inside the chamber (110) such that the internal space (110s) has a predetermined volume; and a pressing actuator (130) configured to be capable of pressing the plunger (120) such that the volume of the internal space (110s) is reduced
Implementation Method 4
a lubricant for the sliding of the plunger may be applied to the inner surface of the chamber of the medicinal liquid injection apparatus
Data Source
AI summary
A medicinal liquid pumping apparatus according to an embodiment disclosed herein includes: a chamber having an internal space, which is not filled with a medicinal liquid, and an injection port connected to the internal space; a plunger disposed inside the chamber such that the internal space has a predetermined volume; and a pressing actuator configured to be capable of pressing the plunger such that the volume of the internal space is reduced.