Pipette Head Thermal Expansion for Tip Fit
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Solution Overview
Problem
Conventional pipetting machines face challenges with inconsistent dimensional accuracy of pipette tips from different manufacturers, leading to tolerance issues and increased repair times due to wear and tear of the O-ring structure, which affects the tightness and efficiency of pipette head and tip combinations.
Innovation Solution
A pipetting module design where the pipette head and tip have different coefficients of thermal expansion, allowing for temperature-controlled adjustments to ensure secure fitting and detachment without wear, using materials like polymethylmethacrylate, polypropylene, or polyethylene for the tip and ceramics or glass for the head, with integrated sensors for precise temperature and pressure monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a groove with O-ring structure is used on the pipette head to engage with the pipette tip, then tightness between the pipette head and tip is achieved, but the groove is susceptible to abrasion and deterioration over time, requiring frequent O-ring replacement and verification
Solution Approach 1:
The invention extracts the O-ring and groove structure from the pipette head and transfers the sealing function to the pipette tip itself. The pipette tip is designed with a conical outer surface that engages with a corresponding conical inner surface on the pipette head, eliminating the need for separate sealing components that wear out.
Solution Approach 2:
The invention makes the pipette tip (which has a shorter service life and is cheaper) bear the sealing structure instead of the expensive pipette head. The disposable nature of the tip means any wear or deterioration affects only the cheap component, not the expensive reusable pipette head.
2Adaptability or versatility
If commercially-available pipette tips from various manufacturers are used, then versatility and availability are improved, but dimensional accuracy is inconsistent due to different designs and tolerances, making it difficult to design a universal pipette head
Solution Approach 1:
The invention uses thermal expansion parameter differences between the pipette head and tip materials to achieve a reliable connection. By selecting materials with different coefficients of thermal expansion (ceramics or glass for the head, polymers for the tip), the system can compensate for dimensional variations in commercially-available tips through temperature-controlled expansion and contraction.
Solution Approach 2:
The invention employs composite material selection where the pipette head is made from materials with low thermal expansion (ceramics or glass) and the pipette tip is made from materials with high thermal expansion (polymers). This composite approach allows the system to accommodate dimensional variations in tips from different manufacturers while maintaining secure engagement.
3Adaptability or versatility
If the pipette head is designed to accommodate all pipette tips, then universality is improved, but the tolerance problem leads to incomplete tightness, requiring customized tips for various pipette models
Solution Approach 1:
The invention introduces dynamic adjustment through thermal expansion. The connection between pipette head and tip is not rigid but dynamically adjustable through temperature changes. Heating causes the tip to expand and seal against the head, while cooling allows for easy detachment, providing both universal compatibility and reliable tightness.
Solution Approach 2:
The invention directly applies thermal expansion principles by selecting materials with different coefficients of thermal expansion. The polymer tip expands more than the ceramic or glass head when heated, ensuring complete tightness and sealing. This resolves the tolerance problem by allowing adjustment beyond the initial dimensional fit.
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 ensures consistent and durable connections between the pipette head and tip, reducing repair times and costs while enhancing inspection efficiency by utilizing thermal expansion and contraction to maintain tightness without abrasion or deterioration.
Implementation Method 1
The second coefficient of thermal expansion of the connecting portion is greater than the first coefficient of thermal expansion of the pipette head
Implementation Method 2
The second coefficient of thermal expansion of the connecting portion is greater than the first coefficient of thermal expansion of the pipette head
Data Source
AI summary
A pipetting module includes a pipette head and a pipette tip. The pipette head has a first coefficient of thermal expansion. The pipette tip includes a connecting portion. The connecting portion is adapted to be sleeved on the pipette head, and the connecting portion has a second coefficient of thermal expansion. The second coefficient of thermal expansion of the connecting portion is greater than the first coefficient of thermal expansion of the pipette head. In addition, an automatic pipetting apparatus is also provided.