Gas Permeability Measurement Cell with High-Pressure Control
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Solution Overview
Problem
Existing systems for measuring gas permeability through thin films or container walls are slow, requiring long measurement times and producing low-intensity signals, especially for low permeability films, making it difficult to compare different films effectively.
Innovation Solution
A method and device that increase the total pressure of gas samples and carriers to 2-15 bar, maintaining a zero pressure difference between chambers to enhance gas flow and signal intensity, allowing quicker measurements and using less sensitive, cheaper sensors, with automatic feedback control for pressure adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If measurement is carried out at atmospheric pressure using known systems, then the system structure is simple and easy to operate, but the measurement time is very long and signal intensity is very low
Solution Approach 1:
The patent applies parameter changes by increasing the total pressure in both chambers from atmospheric pressure to elevated pressure (2-15 bar). This pressure parameter change increases the gas concentration and flow rate through the film, thereby increasing signal intensity and reducing measurement time. The pressure is increased uniformly in both chambers to maintain zero pressure difference, resolving the contradiction between measurement speed and system complexity.
Solution Approach 2:
The patent applies equipotentiality by maintaining equal pressure in both chambers during high-pressure measurement. Pressure control means are provided in both chambers to ensure the pressure difference remains substantially zero, preventing film distortion while benefiting from the increased absolute pressure. This allows the system to achieve faster measurements without complicating the pressure control mechanism.
2Measurement precision
If measurement is carried out at atmospheric pressure, then the system is easy to operate, but the signal intensity is very low especially for low permeability films
Solution Approach 1:
The patent changes the pressure parameter from atmospheric to elevated pressure (2-15 bar) to increase the concentration of gas molecules and the flow rate through the film. This results in higher signal intensity that can be detected by common sensors, improving measurement precision without requiring highly sensitive or expensive sensors.
Solution Approach 2:
The patent uses pneumatic principles by pressurizing the gas samples and carrier gas in both chambers to elevated pressures. This pneumatic approach increases the driving force for gas permeation through the film, generating stronger signals that are easier to detect and measure with standard equipment.
3Productivity
If pressure difference is applied between chambers to increase gas flow, then measurement speed increases, but the film becomes distorted and measurement accuracy decreases
Solution Approach 1:
The patent applies equipotentiality by maintaining equal pressure in both chambers. Pressure control means are provided in each chamber to ensure the pressure difference remains substantially zero, preventing film distortion and maintaining measurement accuracy. Meanwhile, the absolute pressure in both chambers is elevated to increase gas flow and measurement speed.
Solution Approach 2:
The patent changes the pressure parameter by increasing the absolute pressure in both chambers while maintaining pressure equilibrium. This allows the system to achieve faster gas flow rates through the film without creating pressure differences that would distort the film, thus improving measurement speed without sacrificing accuracy.
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 approach significantly reduces measurement time, increases signal intensity, and enables the use of less sensitive sensors, resulting in faster and more reliable permeability assessments compared to traditional methods.
Implementation Method 1
a membrane (2) whose gas permeability is to be measured, said membrane separating said first and second chamber, causing said gas sample to flow into said first chamber and causing a gaseous carrier to flow into said second chamber, an amount of said gas sample permeating in said second chamber through said membrane
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A device for measuring permeability to a gas sample through a thin film, or a wall (2), arranged at membrane between a first and a second chamber (3 and 4) of a measurement cell (1) comprises, upstream from each inlet to the measurement cell (1), a respective regulator of pressure (β and 9) associated with a respective pressure sensor (5 and 8), and can comprise an humifier. The device comprises, furthermore, valves (11 and 12) adapted to switch the flows of gas between a starting wash and a measurement step. Each gas flow is, moreover, adjusted at the exit means of a respective flow regulator (15 and 16). A control unit (23), operates the pressure regulators (6 and 9) and flow regulators (15 and 18) in order to keep at predetermined values the total pressure in the first and in the second chamber (3 and 4), said values being always equal to each other.