Vapor Permeameter
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Description
The principle of the vapor permeameter is the same as that of the diffusion permeameter except that instead of a gas, any noncorrosive vapor is used and the flow rate of the vapor is determined.
Principles of Operation
The basic principle is based on the laws of diffusion.
where F is the flux of vapor across the sample, [dp/dx] is the pressure gradient across the thickness, and M is a measure of diffusivity. The instrument is designed to accurately measure pressure and flow rate. The sample chamber is evacuated. Vapor is maintained at a constant pressure on one side of the sample and the increase in pressure on the other side is measured. The data are used to compute rate of transmission of vapor per unit area of the sample per unit time as a function of pressure gradient.
Applications
Many applications of porous materials require very low water vapor permeability through these materials. Such applications are found in many industries including biotech, healthcare, pharmaceutical, food, and packaging, environmental, power sources and chemical industries. Determination of the magnitudes of low flow rates of vapor through materials used in these applications is important for evaluation of the processes.
Applicable industries are:
Learn more about this instrument's principle and how it measures vapor transmission rates through two commercial textiles.
For more information about our applications please see our other technical papers.
Features
- The sample chamber is maintained at a constant temperature for yielding reliable and reproducible data.
- Fully automated
- Very little operator involvement
- Test time: Can be as little as a few minutes
- Robust. Minimal maintenance
- Measurable flow rate. As low as 10-4 cm3/s
Specifications
For more information see our Diffusion Permeameter Brochure, Permeameter Brochure, and Characterization of Pore Structure Brochure.