Heatable Pipette Inner Wall 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-dimensioned designs.
Innovation Solution
A heatable pipette design where the inner wall acts as a resistor by conducting current directly through it, allowing for resistance heating along its entire length, with adjustable thickness to optimize temperature gradients, and incorporating a conductive connection between the inner and outer walls to facilitate efficient heating and pressure air use.
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, but the temperature uniformity along the needle deteriorates causing crystal formation or precipitation
Solution Approach 1:
The heating function is merged with the needle structure itself by making the inner wall electrically conductive and using it as the heating element. This eliminates the separate heat sink component while achieving uniform heating along the entire needle length through direct resistive heating of the inner wall.
Solution Approach 2:
The inner wall of the needle serves dual functions: as the structural boundary of the inner channel and as the heating element. By conducting current directly through the inner wall, the needle heats itself uniformly along its length without requiring external heating components.
2Stability of the object's composition
If a double walled needle with temperature control element is used, then the temperature uniformity is improved, but the device complexity and manufacturing difficulty increase especially in small dimensions
Solution Approach 1:
The heating function is integrated into the inner wall structure itself rather than being a separate component between the walls. This eliminates the need for complex assembly of temperature control elements and simplifies manufacturing, especially for small-dimensioned needles.
Solution Approach 2:
The inner wall material itself provides the heating capability through its electrical resistance. This self-heating mechanism eliminates the need for separate heating elements, reducing manufacturing complexity while maintaining effective heating in small dimensions.
3Productivity
If the needle dimension is reduced, then the productivity is improved for small volume transfers, but the temperature control capability deteriorates due to insufficient heating section
Solution Approach 1:
The inner wall's electrical resistance provides intrinsic heating capability that scales with the needle dimensions. Even in small-dimensioned needles, the entire length of the inner wall can be heated uniformly by conducting current through it, maintaining temperature control capability while enabling efficient small volume transfers.
Solution Approach 2:
The electrical resistance parameter of the inner wall is utilized to generate heat directly within the needle. By controlling the current through the inner wall, the temperature can be precisely controlled regardless of the needle's small dimensions, ensuring complete heating of the fluid path.
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 precise temperature control and homogeneous heating of the fluid, preventing precipitation and allowing for efficient fluid transfer and filtration processes, even in small dimensions.
Implementation Method 1
By conducting current directly through the inner wall, the inner wall 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. Therefore, the inner wall can directly be used as resistor for resistance heating of 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
Data Source
AI summary
A heatable pipette (1) with a needle (2) has an inner channel (23) defined by an inner wall (21). The pipette (1) is arranged to conduct electric current through the inner wall (21) for resistively heating the inner wall (21). The needle (2) has an outer wall (22), and an outer channel (24) is defined between the outer wall (22) and the inner wall (21). The outer channel (24) is connectable to pressure air means for providing pressure air into the outer channel (24) and the outer channel (24) has outlet openings (26) for providing the pressure air out of the outer channel (24). By conducting current directly through the inner wall (21), the inner wall (21) 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 (21) is not negligible even if the inner wall is very thin. Therefore, the inner wall (21) can directly be used as resistor for resistance heating of the inner wall (21) even if the needle is manufactured in small dimensions.