Gas Flow Path Switching Unit for Multi-Path Chromatography
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Solution Overview
Problem
Conventional Deans-type gas flow path switching units face challenges in efficiently switching between three or more flow paths, leading to increased component count, unit cost, and issues like gas leakage and absorption of sample components, when trying to accommodate multiple detectors in gas chromatographic analysis.
Innovation Solution
A gas flow path switching unit with a main passage branching into multiple sub-passages, connected by switching-gas supply passages and controlled by solenoid valves and resistance tubes, allowing selective discharge to any of multiple outlets by adjusting switching gas pressures, and utilizing a laminated assembly for reduced complexity and component attachment prevention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional Deans-type gas flow path switching unit is used to switch between three or more flow paths, then the switching capability is improved, but the device complexity and component absorption increase
Solution Approach 1:
The gas passage is divided into multiple independent branch passages (first branch passage, second branch passage, third branch passage) that can be independently controlled. Each branch passage has its own flow control capability, allowing the system to selectively direct gas flow to different outlets without requiring complex switching mechanisms for each path.
Solution Approach 2:
The main passage serves multiple functions by being able to direct gas flow to any of the three branch passages. The flow control mechanism is designed to handle multiple flow paths universally, where the same control structure can redirect flow to different outlets based on operational requirements, reducing the need for dedicated switching components for each path.
2Adaptability or versatility
If a movable portion of a three-way valve is placed inside a gas passage to enable switching, then the switching functionality is improved, but dead volume increases and sample gas absorption occurs
Solution Approach 1:
The flow control mechanism is extracted from the gas passage interior and positioned externally. The opening/closing portions are located outside the gas passage, connected through passages that allow flow control without requiring movable components inside the main gas flow path. This eliminates the dead volume and absorption issues associated with internal movable portions.
Solution Approach 2:
Control passages serve as intermediaries between the external opening/closing portions and the main gas passage. These intermediary passages allow the flow control mechanism to operate from outside the gas passage while still effectively controlling the flow direction, eliminating the need for direct internal movable components.
3Adaptability or versatility
If multiple three-way switching valves are used to achieve three or more flow path switching, then the versatility is improved, but gas leakage risk and cost increase
Solution Approach 1:
Multiple flow path control functions are merged into a single integrated flow control mechanism. Instead of using separate three-way switching valves for each flow path, the invention combines all flow direction control into one mechanism with multiple opening/closing portions that can independently control different branch passages, reducing the number of potential leakage points.
Solution Approach 2:
The flow control mechanism is designed to perform multiple switching functions universally. A single mechanism can direct gas flow to any of the three outlets by controlling different combinations of its opening/closing portions, eliminating the need for multiple specialized valves and thereby reducing gas leakage risk associated with multiple sealing interfaces.
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 switching between multiple flow paths with reduced component count and risk of gas component attachment, enhancing analytical accuracy and reproducibility by controlling gas flow direction and pressure.
Implementation Method 1
a gas pressure on the downstream side of the pressure control valve 80 is maintained at a predetermined value P1... a gas pressure on the side of the gas outlet B becomes P1, and a gas pressure on the side of the gas outlet A becomes P1−ΔP
Implementation Method 2
a resistance tube having a given flow resistance is connected between the first and second switching-gas supply passages 75, 76
Data Source
AI summary
Disclosed is a gas flow path switching unit including a gas passage section with a target gas passage for allowing said target gas to pass therethrough. The target gas passage includes a main passage having a proximal end serving as said gas inlet and a number n of branch passages each provided with a respective gas outlet at a terminal end thereof. The branch passages are formed by repeating two or more times a branching process of branching said main passage into two sub passages at a branch point at a distal end of said main passage and further branching at least one of said sub passages into two sub-sub passages at a branch point defined by a distal end of said sub passage. The target gas passage also includes at least a number n of switching-gas supply passages connected to respective intermediate positions of said n branch passages.