High Pressure Degas Assembly for HPLC Systems
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Solution Overview
Problem
Conventional gas removal devices in ion and liquid chromatography systems cannot withstand the high pressures found in modern high-performance liquid chromatography (HPLC) systems, limiting their effectiveness and the overall performance of the chromatography system.
Innovation Solution
A degas assembly with a gas-permeable membrane degas separator that operates at pressures up to 34.47MPa (5000 psi), featuring a pressurized channel extending along the outer periphery of a low-pressure fluid channel, allowing gas to be separated from the eluent while retaining liquid, and using inert polymer tubing to withstand high pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If conventional gas removal devices are used, then gas can be removed from the eluent, but the devices cannot withstand high pressures (limited to below 6.89MPa)
Solution Approach 1:
The device separates the high-pressure eluent flow path from the low-pressure gas removal path using a semipermeable membrane. The membrane divides the chamber into an eluent flow region (withstanding high pressure) and a gas collection region (at low pressure), allowing the system to operate at high pressures while gas is removed in a low-pressure environment.
Solution Approach 2:
A semipermeable membrane acts as an intermediary barrier between the high-pressure eluent stream and the low-pressure gas phase. The membrane allows gas molecules to pass through while blocking liquid eluent, enabling pressure differential maintenance and selective gas removal without direct contact between high-pressure liquid and low-pressure gas spaces.
2Object-affected harmful factors
If high pressure is applied to compress hydrogen gas to insignificant volume, then gas interference with downstream process is reduced, but detector flow cell and suppressor must withstand 6.89MPa or more
Solution Approach 1:
The device extracts gas from the eluent stream before the flow reaches downstream components. By removing gas molecules from the eluent through the semipermeable membrane in advance, the eluent entering the detector and suppressor contains minimal gas, eliminating the need for these components to withstand high pressures for gas compression.
Solution Approach 2:
Gas removal is performed preliminarily before the eluent enters the chromatographic separation and detection stages. The degas chamber removes gas from the eluent stream upstream, so that downstream components receive already-degassed eluent and do not need to be designed for high-pressure gas compression.
3Ease of operation
If gas-permeable tubing is used for gas removal, then gas can be separated from eluent, but tubing must be thick-walled to withstand high pressures
Solution Approach 1:
The semipermeable membrane is positioned only in the region where gas separation is needed (the degas chamber), while the rest of the fluid transport system uses conventional pressure-rated tubing. This localized application of gas permeability allows thin-walled membrane material to be used only where required for gas separation, while overall system pressure containment is handled by robust external housing and connectors.
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
Enables efficient gas removal at higher system pressures, improving chromatography system performance by allowing the use of higher pressures for greater efficiency and performance, reducing the need for additional backpressure devices, and enabling the use of thinner, less costly gas-permeable tubing.
Implementation Method 1
a degas separator (63) defining a fluid barrier between the low pressure fluid channel (58) and the pressurized fluid channel (61), the degas separator (63) configured to retain liquid in the pressurized fluid channel (61) and allow gas to flow through the degas separator (63)
Implementation Method 2
a pressurized channel (61) for carrying eluent from the eluent generator (35) including a gas at a second pressure higher than the first pressure
Data Source
AI summary
A degas assembly including a low pressure fluid channel for carrying a wash fluid at a first pressure, a pressurized channel for carrying eluent including a gas at a second pressure higher than the first pressure, and a degas separator defining a fluid barrier between the low pressure fluid channel and pressurized fluid channel, the separator configured to retain liquid in the pressurized fluid channel and allow gas to flow through the separator to the low pressure fluid channel. The pressurized fluid channel may extend along an outer periphery of the low pressure fluid channel. The eluent may be received from an eluent generator at a pressure of at least about 3300 psi, and in various embodiments up to about 5000 psi. A liquid chromatography system and method are also disclosed.