Piston-Cylinder Pipetting Device with Adjustable Stops
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Solution Overview
Problem
Conventional manual and automated pipetting systems struggle with precise handling of small liquid volumes due to complexity and expense, especially when dealing with large numbers of piston-cylinder units, as they require exact parallelism between plates which is difficult to maintain and costly to achieve.
Innovation Solution
The solution involves designing stops that ensure piston and cylinder plates are parallel only at the upper and lower stop positions, allowing for precise volume adjustment without needing continuous parallel motion, using adjustable stops and a simple drive mechanism to maintain accuracy across multiple units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional manual or automated pipetting systems are used to handle large numbers of piston-cylinder units, then volume precision can be maintained, but device complexity and cost increase significantly
Solution Approach 1:
The patent extracts the critical function of ensuring plate parallelism from the continuous motion phase and concentrates it only at the start and end positions using stops. This removes the need for complex continuous guidance mechanisms while maintaining volume precision, as the stops ensure plates are parallel at the critical moments when volume measurement occurs.
Solution Approach 2:
Instead of maintaining parallelism throughout the entire motion (excessive action), the patent applies parallelism only partially at the critical start and end positions where volume measurement occurs. This partial application of the parallelism requirement reduces device complexity while maintaining sufficient measurement precision.
2Measurement precision
If automated spindle drives are used to move piston units with rapid and precise motion, then pipetting accuracy is improved, but the system becomes too complex and expensive for manual or simple drive operations
Solution Approach 1:
The patent extracts the precision control function from the continuous drive mechanism and relocates it to simple stops at the start and end positions. This allows manual or simple drive operations to achieve the same pipetting accuracy as complex automated systems, by ensuring plates are parallel only when needed for volume measurement.
Solution Approach 2:
The patent replaces expensive, complex automated spindle drives with simple, inexpensive stop mechanisms that can be used with manual or simple drive operations. The stops provide the necessary precision control without requiring costly automated control systems.
3Measurement precision
If exact parallelism between piston plate and cylinder plate is maintained during continuous motion, then volume accuracy is ensured, but the guidance system becomes excessively complex and expensive
Solution Approach 1:
The patent extracts the parallelism enforcement function from continuous motion guidance and concentrates it at discrete start and end positions using stops. This eliminates the need for complex continuous guidance systems while maintaining volume accuracy, as the stops ensure plates are parallel at the critical measurement points.
Solution Approach 2:
Instead of maintaining parallelism throughout the entire motion path (excessive action), the patent applies parallelism only at the critical start and end positions where volume measurement occurs (partial action). This significantly reduces guidance system complexity while maintaining sufficient volume accuracy.
Data Source
AI summary
A device for receiving and dispensing liquids has a plurality of piston-cylinder units (1, 1′, 1″) which are respectively arranged on a piston plate (2) and a cylinder plate (3). The liquid is received and dispensed by displacing the pistons (1′) in the cylinders (1″) by changing the distance between the plates (2, 3), perpendicularly to the plate planes, by means of a drive mechanism (6) and a plate guiding system. The volume can be determined by an upper abutment (4) and a lower abutment (5), at least one of said abutments being regulatable by a regulating means (8). The device is suitable for handling precise volumes of a larger number of piston-cylinder units (1, 1′, 1″) in a technically simple manner. To this end, the same receiving and dispensing volumes of the piston-cylinder units (1, 1′, 1″) are ensured with low requirements in terms of the surface parallelism of the plate planes during the movement in the plate guiding device, by structuring and arranging the abutments (4, 5) in such a way that the parallelism of the plates (2, 3) is obtained in the upper (9) and lower (10) abutment positions.