Dual-Drive Sampler for High-Pressure HPLC
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Solution Overview
Problem
High-performance liquid chromatography requires precise sample dosing at high pressures, but existing systems face challenges in maintaining precision and mechanical strength, leading to wear and poorer reproducibility due to the high forces involved in pre-compression.
Innovation Solution
The use of two independent drives, one for high-precision dosing and the other for pre-compression, allows for precise sample volume collection and high-pressure handling without exposing the precision components to excessive loads, with mechanical decoupling to protect the metering drive from compression forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single drive is used for both high-precision dosing and pre-compression, then the device complexity is reduced, but the manufacturing precision and reliability deteriorate due to wear and load on precision components
Solution Approach 1:
The drive system is segmented into two independent drives: a metering drive for high-precision piston positioning during sample aspiration, and a compression drive for pre-compression of the sample loop. This segmentation allows each drive to be optimized for its specific function, preventing wear and load transfer between functions and maintaining manufacturing precision.
2Strength
If robust components are used to withstand high pre-compression forces, then the strength and durability are improved, but the manufacturing precision and dosing accuracy deteriorate
Solution Approach 1:
The system separates the high-force pre-compression function from the high-precision dosing function by using independent drives. The compression drive handles high forces with robust components, while the metering drive maintains precision with lighter, more accurate components, eliminating the trade-off between strength and precision.
3Stress or pressure
If the piston is subjected to high forces during pre-compression, then the necessary pressure buildup is achieved, but the reliability deteriorates due to wear and abrasion on the spindle
Solution Approach 1:
The drive system is divided into two independent drives operating at different times. The metering drive operates during aspiration at ambient pressure, avoiding high forces. The compression drive operates during pre-compression, bearing the high forces. This temporal and functional segmentation protects the precision components from wear and abrasion, maintaining reliability over time.
4Device complexity
If a single drive performs both dosing and compression functions, then the device simplicity is maintained, but the measurement precision deteriorates due to load on precision components
Solution Approach 1:
The measurement function is separated from the compression function. The metering drive, responsible for precise sample volume measurement and dosing, operates independently during aspiration at ambient pressure. The compression drive handles pre-compression separately. This segmentation ensures measurement precision is not compromised by loads on precision components.
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 approach enables precise and reproducible sample volume delivery at high pressures, protecting high-precision components from excessive loads and maintaining precision, while ensuring mechanical strength for pre-compression, thus optimizing sampler performance in liquid chromatography.
Implementation Method 1
a first drive (1) is provided, which is designed for high-precision positioning of the piston in the cylinder, in order to be able to aspirate a precisely defined sample volume into the sample loop
Implementation Method 2
a second drive (2) is provided, which is capable of acting on the piston via high piston forces, in order to be able to build up pressures in excess of 100 MPa
Implementation Method 3
The piston is urged into a retracted position by permanently acting tensioning means, from which position it can be moved when acted upon by the metering drive or the compression drive
Data Source
AI summary
The invention relates to a sampler for providing a sample for high-performance liquid chromatography, in which a volume of liquid to be taken up into a cylinder can be aspirated by means of a first drive and can be compressed to a high pressure level by means of a second drive independent of the first drive or can be decompressed from this level in a controlled manner.