Pipette Tip Kinks for Fluid Volume Control
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Solution Overview
Problem
Existing pipette tips lack precision and accuracy in aspirating and dispensing small volumes of liquid, particularly when used with laboratory automation devices, leading to uncontrollable fluid movements due to capillary forces during pressure changes.
Innovation Solution
The pipette tip design features a series of sections with strategically placed kinks in the inner surface, creating positive kinks that allow the fluid level to stick and control the aspirated or dispensed volume accurately, with angles between 1° and 5°, enhancing the control of fluid volumes between 0.3 μl and 5 μl.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional pipette tips are used without kinks in the inner surface, then the structure is simple and easy to manufacture, but the accuracy and precision of fluid aspiration and dispensing deteriorates due to uncontrollable capillary forces
Solution Approach 1:
The inner surface of the pipette tip is segmented into multiple sections with different angles (first section with smaller angle, second section with larger angle) separated by kinks. This segmentation allows different regions to control capillary forces at different stages of fluid aspiration and dispensing, achieving precise volume control while maintaining manufacturing simplicity.
Solution Approach 2:
Different sections of the pipette tip inner surface are given different local properties through the kinks and angle variations. The first section has a smaller angle for initial fluid uptake, while the second section has a larger angle for controlled dispensing. This local differentiation enables precise control over fluid movement without requiring complex overall structure.
2Ease of operation
If the inner surface has smooth continuous geometry, then manufacturing is easier, but the control of fluid level and aspirated volume deteriorates due to lack of capillary anchoring points
Solution Approach 1:
Kinks are pre-formed in the inner surface at specific locations before the pipette tip is put into service. These kinks create predetermined anchoring points for capillary forces that will naturally guide fluid level during aspiration and dispensing operations, providing easy control without requiring complex manufacturing processes.
Solution Approach 2:
The kinks act as intermediary structures between the smooth inner surface and the fluid. They provide physical anchoring points that mediate the capillary forces, allowing the fluid level to stick at specific positions. This intermediary approach enables easy fluid level control while keeping the overall manufacturing process simple.
3Manufacturing precision
If kinks with large angle differences are used, then the control of fluid volume is improved, but the manufacturing precision requirements deteriorate
Solution Approach 1:
The invention uses moderate angle differences (first angle between 0-5 degrees, second angle between 5-15 degrees) rather than extreme values. This parameter optimization ensures that the kinks provide sufficient capillary anchoring for reliable fluid level control while remaining within the capabilities of standard manufacturing processes, avoiding excessive precision requirements.
Solution Approach 2:
The kinks are designed with sufficient angle differences to reliably control fluid volume, but not excessively large angles that would be difficult to manufacture. The first section angle is kept small (0-5 degrees) and the second section angle is moderate (5-15 degrees), providing just enough capillary force for reliable control without over-engineering the structure.
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 significantly improves the accuracy and precision of fluid aspiration and dispensing, allowing for well-controllable volumes, especially at lower volumes, by utilizing capillary forces to maintain the fluid level at specific kinks, reducing uncontrollable movements.
Implementation Method 1
maintain the fluid level at specific kinks, reducing uncontrollable movements
Data Source
AI summary
A pipette includes an end section, a first section, a second section and a third section aligned along a central axis of the pipette tip. The end section comprises an orifice for aspirating and dispensing a fluid. A first kink is formed in an inner surface of the pipette tip between the first section and the second section, such that an angle between the inner surface of the first section and the central axis is smaller than an angle between the inner surface of the second section and the central axis. A second kink is formed in the inner surface of the pipette tip between the second section and the third section, such that the angle between the inner surface of the second section and the central axis is smaller than an angle between the inner surface of the third section and the central axis.