Multi-Channel Pipette Ejector with Stepped Contact Elements
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Solution Overview
Problem
Multi-channel pipettes require high force to eject multiple pipette tips due to strong clamping forces needed for secure seating and sealing, making the process labor-intensive and inefficient.
Innovation Solution
A multi-channel pipette design featuring pegs with spring-loaded displacement devices and an ejector system with stepped contact elements, where the ejector moves in a way that first one contact element pushes off pipette tips, followed by subsequent elements, reducing the maximum force required for ejection by distributing the force over multiple tips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If strong clamping forces are applied to securely seat and seal multiple pipette tips on the spigots, then the sealing and seating reliability is improved, but the force required to eject the tips increases significantly
Solution Approach 1:
The ejector is divided into multiple ejector parts (first ejector part, second ejector part, etc.), each with its own contact element. These parts are arranged at different heights and can move independently or in sequence, allowing the ejection force to be distributed across multiple tips rather than applied simultaneously to all tips. This segmentation reduces the maximum force required at any one moment during ejection.
Solution Approach 2:
The ejector parts are designed to move in a sequential or staged manner rather than simultaneously. The first ejector part moves to eject a first group of tips, then the second ejector part moves to eject a second group of tips. This periodic action distributes the ejection force over time and reduces the peak force requirement, while the strong clamping forces remain in place to ensure reliable sealing during the liquid transfer operation.
2Force
If a stepped stop element is used to reduce ejection force by impacting tips one after another, then the maximum ejection force is reduced, but the attachment heights of the tips vary
Solution Approach 1:
Instead of using a single stepped stop element that creates varying attachment heights, the invention segments the ejector into multiple ejector parts (first ejector part, second ejector part, etc.), each with its own contact element. These contact elements are arranged at different heights but all engage with tips that remain at the same attachment height on the spigots. This segmentation allows force distribution without compromising attachment uniformity.
Solution Approach 2:
The multiple ejector parts act as intermediaries between the driving force and the pipette tips. Each ejector part is designed to engage with a specific subset of tips at their uniform attachment height, translating the sequential motion into distributed ejection force without altering the tips' attachment positions on the spigots. This intermediary mechanism resolves the conflict between force reduction and height uniformity.
3Productivity
If all contact elements of the ejector move simultaneously, then the ejection process is faster, but the maximum force required increases significantly
Solution Approach 1:
The ejector parts are designed to move in a periodic or sequential manner rather than simultaneously. The first ejector part moves to eject a first group of tips, then the second ejector part moves to eject a second group of tips. This periodic action reduces the peak force requirement by distributing the ejection load over time, while still maintaining high productivity through the coordinated sequential operation of multiple ejector parts.
Solution Approach 2:
The ejector is segmented into multiple independently controllable parts, each responsible for ejecting a subset of tips. This segmentation allows the system to maintain high productivity by having multiple parts operate in parallel or rapid sequence, while each individual part applies only the necessary force for its subset of tips, thereby reducing the maximum force requirement compared to a single ejector moving all tips simultaneously.
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 reduces the effort needed to eject multiple pipette tips by limiting the clamping force and ensuring all tips are securely seated while allowing for efficient ejection without varying attachment heights, thus minimizing the overall ejection force.
Implementation Method 1
first spring elements acting on the pin and on the base body, with the pin opposing the spring action of the first spring elements can be displaced upwards from a starting position in their longitudinal direction
Implementation Method 2
an ejection device for releasing pipette tips from the pins, comprising an ejector which has contact elements... downwards in the longitudinal direction of the pins in order to use the contact elements to move the pipette tips away from the pins
Data Source
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AI summary
The pipette has spring elements which are designed by clamping up pipette tips (89) onto the spigots (26). The spigots are dislocated towards contact element in stop position, such that pipette tips hit contact element. Ejection equipment is provided with mounting section for mounting an ejector (43) on base (5), so as to be slidable in longitudinal direction of spigots. A drive device is connected to ejector. The ejector is provided with contact elements on different ejector portions (44,63) to squeeze off pipette tips from spigots.