Mass Spectrometer Pulse Valve Pressure Control
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Solution Overview
Problem
Existing mass spectrometers face challenges in maintaining sensitivity and preventing contamination when using small-sized evacuation pumps, as direct ion introduction methods lead to low transmission efficiency and clogging, while differential pumping methods require additional pumps and suffer from valve durability issues due to high pressure ratios.
Innovation Solution
A mechanism involving a pre-valve evacuation region with a pressure range of 100 to 10,000 Pa, combined with a pulse valve for controlled ion introduction, reduces gas flow and contamination, enhancing ion transmission efficiency and valve durability by mitigating pressure ratios and leak rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a thin capillary is used for direct ion introduction from atmospheric-pressure ion source to high-vacuum chamber, then the device complexity is reduced, but the ion transmission efficiency deteriorates and the capillary tends to clog
Solution Approach 1:
The patent divides the vacuum system into multiple stages with different pressure levels. A medium-vacuum chamber is introduced between the atmospheric-pressure ion source and the high-vacuum mass spectrometry part, creating a segmented pressure gradient that improves ion transmission while preventing direct clogging issues
Solution Approach 2:
The medium-vacuum chamber acts as an intermediary stage between the atmospheric-pressure ion source and the high-vacuum mass spectrometry part. This intermediate chamber with controlled pressure (10^-2 to 10^-4 Pa) serves as a buffer that facilitates ion transmission without direct exposure to extreme pressure differences
2Productivity
If differential pumping chambers are used to increase ion introduction amount, then the ion transmission efficiency is improved, but the device complexity and number of pumps increase
Solution Approach 1:
The patent combines the medium-vacuum chamber with the ion source chamber, eliminating the need for separate differential pumping chambers. The ion source chamber itself serves as the medium-vacuum environment, reducing the total number of vacuum chambers and pumps required
3Productivity
If pulse valve is used to control ion flow timing, then the ion introduction amount is increased, but the valve durability deteriorates due to high pressure ratios
Solution Approach 1:
The patent dynamically adjusts the pressure in the medium-vacuum chamber to operate within an optimal range (10^-2 to 10^-4 Pa). This dynamic pressure control optimizes the pressure ratio across the pulse valve, reducing mechanical stress and extending valve lifespan while maintaining high ion introduction efficiency
4Volume of moving object
If small-sized evacuation pump is used for portable design, then the device size is reduced, but the ability to maintain sensitivity and prevent contamination deteriorates
Solution Approach 1:
The patent segments the vacuum system into multiple pressure stages, allowing each pump to operate within its optimal performance range. The small pump only needs to maintain the medium-vacuum chamber at 10^-2 to 10^-4 Pa, which is less demanding than maintaining high vacuum, enabling portable design while preserving sensitivity
Solution Approach 2:
Different regions of the system are maintained at different pressure levels optimized for their specific functions. The medium-vacuum chamber is maintained at a pressure level that prevents contamination while allowing efficient ion transmission, and this local optimization enables the use of smaller pumps
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 configuration improves ion introduction efficiency, maintains sensitivity, and extends valve lifespan by controlling pressure ratios and reducing contamination, allowing for a compact, portable mass spectrometer design.
Implementation Method 1
a pump mechanism for evacuating to bring the pressure on a high pressure side of the sample introducing piping part, that is, a pressure on an opposite side of the opening/closing mechanism to the mass spectrometry part equal to 100 Pa or greater and equal to 10,000 Pa or less
Data Source
AI summary
A mass spectrometer having a resolution improved by introducing ions into a mass spectrometry part with a high efficiency is provided with a small-sized, simple configuration. The mass spectrometer includes an opening/closing mechanism provided between a sample introducing piping part for introducing a sample into the mass spectrometry part and the mass spectrometry part to conduct gas introduction intermittently and control sample passage. The mass spectrometer further includes a pump mechanism to evacuate a high pressure side of the sample introducing piping part, that is, an opposite side of the opening/closing mechanism to the mass spectrometry part to have a pressure in a range of 100 to 10,000 Pa.