HPLC Degassing Device with Dynamic Vacuum Control
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Solution Overview
Problem
In HPLC systems, the stagnation of the mobile phase in the degassing device after analysis completion leads to evaporation and potential damage due to corrosion or swelling of components, especially with solvents like chloroform, as existing degassing devices do not effectively prevent vaporized mobile phase from staying in the vacuum chamber or pump.
Innovation Solution
A degassing device with a degassing flow path, vacuum chamber, vacuum pump, inlet, outlet, and drain flow paths, along with a controller that switches the downstream end to the drain path when the mobile phase feeding is stopped, preventing mobile phase stagnation and allowing for controlled drainage or cleaning, and optionally using an atmospheric open path or cleaning solution flow path to manage solvent usage and device maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the degassing device operates continuously with the vacuum pump running, then gas components are effectively extracted from the mobile phase, but the mobile phase evaporates and permeates the gas-permeable tube to be stayed in the vacuum chamber or vacuum pump, causing component damage
Solution Approach 1:
The system performs preliminary action by stopping the vacuum pump before the mobile phase can significantly evaporate and damage components. The controller monitors pump operation status and coordinates shutdown timing to prevent harmful effects while maintaining degassing effectiveness during active pumping.
Solution Approach 2:
The system dynamically adjusts vacuum pump operation based on real-time conditions. The controller activates or deactivates the vacuum pump according to whether the liquid feeding pump is currently feeding mobile phase, creating a dynamic operational state that prevents damage while maintaining functionality when needed.
2Object-affected harmful factors
If the vacuum pump is stopped to prevent evaporation, then component damage is avoided, but gas components cannot be extracted from the mobile phase
Solution Approach 1:
The vacuum pump operation is made dynamic rather than static. The controller continuously monitors the operational state of the liquid feeding pump and adjusts the vacuum pump state accordingly - running when needed for degassing, stopped when not needed to prevent damage. This dynamic control resolves the contradiction between maintaining function and preventing harm.
Solution Approach 2:
The system implements feedback control where the controller receives information about the liquid feeding pump's operational status and uses this feedback to control the vacuum pump. This closed-loop control ensures the vacuum pump operates only when mobile phase is flowing, maintaining degassing effectiveness while preventing evaporation damage during idle periods.
3Device complexity
If a single switching unit is used to control both inlet and outlet flow paths, then device complexity is reduced, but the ability to independently control mobile phase flow and drainage is limited
Solution Approach 1:
The switching control is segmented into two independent units: a first switching unit for the inlet flow path and a second switching unit for the outlet flow path. This segmentation allows independent control of mobile phase entry and exit, providing the versatility needed for different operational modes (degassing, drainage, cleaning) while keeping each individual switching unit relatively simple.
Solution Approach 2:
The dual switching unit configuration provides multi-functionality, enabling the system to perform multiple operations: normal degassing mode, drainage mode, and cleaning mode. Each switching unit can be independently positioned to achieve different flow path configurations, making the system adaptable to various operational requirements without increasing the complexity of individual 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
Prevents mobile phase evaporation and subsequent damage to the degassing device components by draining the mobile phase at predetermined times, reducing solvent waste and maintaining system integrity during analysis breaks.
Implementation Method 1
a degassing flow path made of a gas-permeable, liquid-impermeable tube is provided in a sealed space called a vacuum chamber to extract gas components from the liquid flowing through the degassing flow path
Implementation Method 2
The vacuum pump is connected to the vacuum chamber to reduce the pressure in the vacuum chamber
Data Source
AI summary
The degassing device includes a degassing flow path, a vacuum chamber, a vacuum pump, an inlet flow path, an outlet flow path, a drain flow path, a downstream side switching unit, and a controller. The degassing flow path is made of a gas-permeable, liquid-impermeable tube, and is accommodated in the vacuum chamber. The inlet flow path is for introducing a mobile phase to the degassing flow path, and the outlet flow path is for causing a mobile phase which has passed through the degassing flow path to flow out. The drain flow path is provided separately from the outlet flow path and is configured to drain the mobile phase in the degassing flow path from the degassing flow path. The downstream side switching unit is configured to switch the downstream end of the degassing flow path so as to be connected to either the outlet flow path or the drain flow path. The controller controls the operation of the downstream side switching unit, and is configured to connect the downstream end of the degassing flow path to the drain flow path at a predetermined timing when feeding of the mobile phase by the liquid feeding pump is stopped to drain the mobile phase in the degassing flow path through the drain flow path.