Liquid Container Extraction Chimney for Stable Pipetting
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Solution Overview
Problem
In high-throughput automated analyzers, liquid containers experience rapid liquid swashing and foaming when abruptly stopped, leading to unstable liquid levels and contamination risks, which existing designs cannot address within the required short cycle times.
Innovation Solution
Incorporating a finely-porous flow resistance element at the lower end of the withdrawal chimney to dampen liquid movements and prevent foam passage, combined with a venting groove at the upper end for rapid pressure equalization, allowing controlled pipetting with minimal liquid entrainment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the liquid container is rapidly conveyed and abruptly stopped in the pipetting zone to achieve high throughput, then productivity is improved, but the liquid level becomes unstable and causes contamination
Solution Approach 1:
The withdrawal chimney acts as an intermediary structure between the liquid container and the pipette tip. It provides a controlled interface that isolates the pipette tip from the unstable liquid movements in the main container, allowing rapid container handling while maintaining stable liquid access for pipetting.
Solution Approach 2:
The liquid-permeable zone in the lower end region of the withdrawal chimney functions as a flexible barrier that allows liquid to pass through while filtering out foam and large air bubbles. This selective permeability stabilizes the liquid level in the chimney during rapid container deceleration.
2Quantity of substance
If the pipette tip dips deeply into the liquid to ensure adequate sampling, then the fill volume is sufficient, but liquid adheres to the outside of the tip causing contamination
Solution Approach 1:
The withdrawal chimney serves as an intermediary that confines liquid to its internal space during pipetting. The pipette tip only contacts liquid within the chimney boundaries, preventing liquid from adhering to the external surface of the tip and causing contamination in subsequent operations.
Solution Approach 2:
The liquid container system is segmented into distinct functional zones: the main liquid storage area, the withdrawal chimney with controlled liquid access, and the pipette tip interaction zone. This segmentation isolates the pipetting operation to a controlled environment within the chimney.
3Productivity
If the liquid container is stopped rapidly to maintain short cycle times, then productivity increases, but foam formation in the withdrawal chimney occurs
Solution Approach 1:
The liquid-permeable zone in the lower end region of the withdrawal chimney uses porous material properties to selectively allow liquid passage while blocking foam and large air bubbles. The pore structure provides capillary pressure that prevents foam formation in the chimney during rapid container deceleration.
Solution Approach 2:
The rapid deceleration that causes harmful foam formation in conventional containers is converted into a beneficial effect: the inertial forces push liquid downward through the porous zone, ensuring adequate liquid supply to the chimney bottom while the porous structure simultaneously filters out the resulting foam.
4Reliability
If the liquid level is allowed to equalize before pipetting to ensure stability, then reliability improves, but the required waiting time exceeds the available cycle time
Solution Approach 1:
The withdrawal chimney provides immediate liquid stability for pipetting without requiring the entire container to equalize. The chimney's narrow geometry and liquid-permeable zone create a localized stable liquid environment that is ready for pipetting as soon as the container stops, eliminating the need for extended waiting periods.
Solution Approach 2:
The withdrawal chimney is pre-configured with its liquid-permeable zone and narrow geometry to maintain liquid stability in advance. When the container is rapidly decelerated, the chimney's structure immediately begins stabilizing the liquid level, so pipetting can proceed without additional waiting time.
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 stable and rapid liquid level changes in the withdrawal chimney, reducing contamination risks and enabling reliable pipetting within short cycle times, even during high-throughput operations.
Implementation Method 1
the liquid-permeable zone has at least one finely-porous flow resistance element so that liquid exchange between the withdrawal chimney and the interior space of the container which surrounds it in the region of the liquid-permeable zone can only take place by way of a respective flow resistance element
Implementation Method 2
finely-porous flow resistance element so that liquid exchange... can only take place by way of a respective flow resistance element
Implementation Method 3
a venting groove at the upper end for rapid pressure equalization
Implementation Method 4
venting groove at the upper end for rapid pressure equalization
Data Source
AI summary
A liquid container with an upper opening and a tube-shaped withdrawal chimney is disclosed. The withdrawal chimney extends into the container through the upper opening which has a liquid-permeable zone in the form of a finely-porous flow resistance element in its lower end region such that liquid exchange can take place between the withdrawal chimney and the container inner space which surrounds it via the flow resistance element. A venting groove formed by a radial recess of the casing wall of the withdrawal chimney in its upper region may be provided to ensure adequate venting of the space above the liquid level.