Gas Sampler Buffer Flow Path Negative Pressure Suction
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Solution Overview
Problem
In gas analyzers, particularly micro gas chromatographs, the small volume of the sample loop often results in insufficient sample gas being sucked into the loop due to the volume of the introduction flow path being larger than the sample loop, leading to inadequate gas supply to the column.
Innovation Solution
A gas sampler with a buffer flow path volume greater than the introduction flow path volume, using a suction pump to set the buffer flow path to negative pressure, and then introducing sample gas from the sample tank into the sample loop without active suction, ensuring sufficient gas is trapped and supplied to the column.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sample loop volume is reduced to achieve micro gas chromatography, then the analysis sensitivity is improved, but the sample gas cannot be sufficiently sucked into the loop due to the introduction flow path volume being larger than the sample loop volume
Solution Approach 1:
The system performs preliminary action by setting the buffer flow path to negative pressure before introducing the sample gas. This negative pressure state is established in advance to ensure that when the switching valve opens, the sample gas is rapidly drawn into the sample loop without being limited by the introduction flow path volume. The negative pressure buffer flow path acts as a pre-prepared suction mechanism that overcomes the volume mismatch problem.
Solution Approach 2:
The buffer flow path serves as an intermediary between the suction pump and the sample loop. It transmits the negative pressure from the pump to the sample loop while providing sufficient volume to accommodate the introduction flow path. This intermediary buffer volume allows the system to decouple the pump's suction capability from the sample loop's small volume, enabling efficient sample gas transfer without direct connection constraints.
2Speed
If a pump is used to create negative pressure for sample gas introduction, then the sample gas suction speed is improved, but the sample loop volume is insufficient to receive adequate sample gas when the introduction flow path volume is larger
Solution Approach 1:
The invention adds another dimension to the system by introducing a buffer flow path with volume greater than the introduction flow path. This additional volume dimension allows the negative pressure to act more effectively by providing a larger pressure equalization space. The buffer volume acts as a pressure buffer that maintains the negative pressure gradient long enough for sufficient sample gas to enter the small sample loop, even when the introduction path volume exceeds the loop volume.
3Measurement precision
If the sample loop volume is made very small for micro gas chromatography, then the detection limit is improved, but the volume ratio between the sample loop and introduction piping causes insufficient gas supply to the column
Solution Approach 1:
The system establishes negative pressure in the buffer flow path before the sample introduction occurs. This preliminary negative pressure state ensures that when the switching valve opens, the sample gas is immediately drawn into the sample loop with sufficient force and volume, overcoming the unfavorable volume ratio between the small sample loop and the larger introduction piping.
Solution Approach 2:
The buffer flow path acts as an intermediary volume that compensates for the size mismatch between the introduction piping and the sample loop. It provides sufficient volume to accommodate the introduction flow path while transmitting the negative pressure effect to the small sample loop, ensuring reliable sample gas supply despite the small loop volume required for micro gas chromatography.
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 method ensures an appropriate amount of sample gas is supplied to the column, reducing wasteful consumption and maintaining analysis accuracy by adjusting the buffer tank volume to match the introduction piping volume, thereby preventing gas shortages.
Implementation Method 1
adjusting a pressure of an inside of the buffer flow path to a negative pressure by operating the suction pump
Data Source
AI summary
A gas sampler includes a connection portion connectable to an introduction piping connected to a sample tank, a switching valve for switching a connection state between the connection portion and a sample loop, a pump, and a control device. A buffer flow path between the sample loop and the pump is configured to be selectively connectable to any one of a plurality of buffer tanks different in volume. A volume of the buffer flow path is greater than a volume of the introduction piping by a predetermined amount. The control device operates the pump in a state in which the switching valve is in a closed state to set an inside of the buffer flow path to a negative pressure, and thereafter stops the pump and make the switching valve in an open state to fill the sample loop with a sample gas by using the negative pressure of the buffer flow path.