Heatable Pipette Needle Resistive Heating
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Solution Overview
Problem
Existing heatable pipettes struggle to maintain a consistent temperature along the length of the needle, leading to potential crystal formation or precipitation due to temperature gradients, especially in small dimensions where efficient temperature control is challenging.
Innovation Solution
A heatable pipette design where electric current is conducted through the inner wall of the needle, made of materials like stainless steel, to achieve resistive heating along its entire length, with an outer channel for pressure air and a conductive connection allowing current flow through both walls, enabling precise temperature control and homogeneous heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a heat sink encloses only a section of the needle, then the device complexity is reduced and manufacturing is simplified, but the temperature distribution becomes non-uniform causing crystal formation or precipitation
Solution Approach 1:
The patent replaces the mechanical heat sink system with an electrical heating system. Instead of using a physical heat sink that encloses sections of the needle, the invention uses an electrically conductive needle where current flows through the entire length to generate heat uniformly via Joule heating. This substitution eliminates the complex mechanical heat sink structure while achieving uniform temperature distribution along the entire needle length.
2Temperature
If a double walled needle with temperature control element is used to heat the entire needle length, then temperature uniformity is improved, but the device complexity increases and small dimensions become difficult to achieve
Solution Approach 1:
The patent makes the needle itself serve multiple functions: it acts as both the structural component for fluid transport and as the heating element. By making the needle electrically conductive and having current flow through it, the needle simultaneously performs mechanical support, fluid conveyance, and thermal generation functions. This eliminates the need for separate heating elements or double-walled structures, simplifying the design while maintaining temperature uniformity.
3Adaptability or versatility
If the needle dimensions are reduced for small dimension applications, then adaptability is improved, but efficient temperature control becomes challenging and temperature uniformity deteriorates
Solution Approach 1:
The patent replaces complex thermal management mechanisms with simple electrical current flow through the needle. This electrical heating approach is particularly effective for small dimensions because the current can be easily controlled to provide precise heating along the entire needle length, regardless of its small size. The electrical system provides superior temperature control efficiency compared to mechanical heat sinks, especially in miniaturized applications.
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 ensures consistent temperature maintenance along the needle, preventing precipitation and allowing for efficient fluid handling, while the outer channel facilitates pressure-driven fluid transfer, enhancing application versatility.
Implementation Method 1
The pipette is arranged to conduct an electric current through the inner wall for resistively heating the inner wall wherein, preferably, the electric current is conducted in an essentially longitudinal direction through the inner wall
Implementation Method 2
a conductive connection between the outer wall and the inner wall is arranged at a distal end region of the pipette and the pipette is arranged to conduct electric current through the inner wall and the outer wall via the conductive connection
Implementation Method 3
the pressure air provided into the filter chamber via the outlet openings effects an overpressure inside the filter chamber. This overpressure can drive a fluid provided into the filter chamber by the needle through the filter element into the collecting chamber
Data Source
AI summary
A heatable pipette, with a needle has an inner channel defined by an inner wall, arranged to conduct electric current through the inner wall for resistively heating the inner wall. The needle has an outer wall, which is defined between the outer wall and the inner wall and connectable for providing pressure air into the outer channel. By conducting current directly through the inner wall, the inner wall itself operates as resistor. Particularly, if the inner wall is made of an appropriate material, for example of stainless steel, the ohmic resistance of the inner wall is not negligible even if the inner wall is very thin. Therefore, the inner wall can directly be used as resistor for resistance heating of the inner wall even if the needle is manufactured in small dimensions.