Automatic Analyzer Sample Loop Control for Viscosity and Bubble Reduction
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Solution Overview
Problem
Existing automatic analyzers face challenges in achieving structural simplicity, maintenance-free robustness, shortening washing and sample introduction processes for improved throughput, and optimizing measurement precision due to issues like bubble introduction and backlash in syringe mechanisms.
Innovation Solution
A control method for an automatic analyzer using a switch valve with multiple sample ports, a sample loop, and a syringe, where the valve switches between sample ports and the syringe to optimize sample introduction and washing processes, adjusting drive parameters based on sample viscosity to prevent bubble formation and improve precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If Direct-Injection mode is used to eliminate sample waste, then sample utilization is improved, but device complexity increases due to high pressure requirements and integrated sipper-structure
Solution Approach 1:
The system divides the sample introduction path into separate segments: a syringe for sample aspiration, a six-port two-position valve for routing, and a sample loop for injection. This segmentation allows the syringe to operate at atmospheric pressure while the HPLC system maintains its required high pressure, eliminating the need for a complex integrated high-pressure sipper structure.
Solution Approach 2:
The six-port two-position valve acts as an intermediary device that bridges the low-pressure syringe sample introduction and the high-pressure HPLC system. By using this valve as a mediator, the system can transfer sample without requiring the entire introduction path to withstand high pressure, thus simplifying the overall structure while preventing sample waste.
2Device complexity
If Partial-Loop-Injection mode is used to simplify structure, then device complexity is reduced, but sample utilization deteriorates causing sample waste
Solution Approach 1:
The system dynamically switches between different injection modes using the six-port two-position valve. The valve can be positioned to enable either partial loop injection (for simplicity) or direct injection of the entire aspirated sample (for complete utilization). This dynamic flexibility allows optimization of sample usage without permanently committing to a complex integrated structure.
Solution Approach 2:
The six-port two-position valve provides multi-functionality by serving both as a routing valve for partial loop injection and as a means to achieve complete sample injection. This single component enables the system to adapt to different sample volume requirements and injection modes, achieving complete sample utilization without requiring separate dedicated structures for each mode.
3Productivity
If syringe drive speed is increased to shorten sample introduction process, then productivity is improved, but measurement precision deteriorates due to bubble introduction and backlash
Solution Approach 1:
The system performs preliminary actions by aspirating a column of air above the sample in the syringe before actual sample injection. This air column acts as a buffer that prevents bubbles from forming during high-speed sample aspiration and injection. The air cushion is established in advance, allowing faster drive speeds without compromising measurement precision.
Solution Approach 2:
The patent replaces purely mechanical direct sample aspiration with a modified system that uses air cushioning. Instead of directly aspirating sample at high speed (which causes bubbles), the system first aspirates air to create a cushion, then uses this cushioned environment for sample injection. This substitution of the aspiration mechanism with an air-cushioned approach eliminates bubble formation while maintaining high productivity.
Data Source
AI summary
A control method for an automatic analyzer that can improve robustness, throughput, and measurement accuracy. The automatic analyzer includes a sample loop connected between two sample ports of a plurality of sample ports of a switch valve. The method includes the steps of: adjusting a drive parameter of the syringe corresponding to a viscosity of the sample acquired in advance; switching the switch valve to a first state in which the sipper and the syringe contact with each other without through the sample loop; driving the syringe based on the drive parameter to draw and introduce the sample through the sipper; switching the switch valve to a second state in which the syringe and the sample loop conduct with each other; and driving the syringe based on the drive parameter to introduce the sample into the sample loop.