Current research projects

Image CFE-Test of Cooker Hoods
Image Humidifier System for High-Purity Gases
Image Cryogenic liquid piston pumps for cold liquefied gases like LIN, LOX, LHe, LH2, LNG, LAr
Image High temperature heat pump
Image Filter Tests
Image Modular storage system for solar cooling
Image Ice Slurry Generation
Image Reduction of primary noise sources of fans
Image Multifunctional electronic modules for cryogenic applications
Image Overall System Optimization of Refrigeration Plant Systems for Energy Transition and Climate Protection
Image Tensile and compression testing
Image Certifiable connection types in cryogenics
Image Low temperature – test facilities
Image All-in-one device for freeze-drying and production of biomaterial
Image Practical training, diploma, master, bachelor
Image Behavior of multiphase cryogenic fluids

You are here:   /  Home


Investigation of material-dependent parameters

7016

Permeation is the penetration of solid matter by another substance. The driving force for this is a gradient of the chemical potential of the permeate. In practice, this gradient is replaced by a measurable quantity such as the pressure gradient. The permeability of a material depends on the surface temperature and is usually specified with the unit \( \frac{\mu g}{cm^2\:min} \)

Without external influences, the permeate always moves in the direction of the lower concentration or the lower partial pressure. For theoretical consideration, permeation can be divided into three sections across the solid:

  • Sorption, for example, a gas is absorbed at the surface of the solid
  • Diffusion, this gas diffuses through the solid through molecular gaps towards the surface with a lower gas concentration
  • Desorption, the gas is released again from this surface

The experimental setup to investigate this process, see the following figures, essentially consists of a sample chamber. The sample is mounted with a seal or against a sealing surface. A test gas with a defined overpressure is applied to the volume on the "left" of the sample. The volume to the "right" of the sample is connected to a detector. The pressure on both sides of the sample, the temperatures and the gas flow rate are measured over a longer period of time (24 - 48 h).

Parameter Sample limits
materials plastics, metals
dimensions, diameter, and wall thickness 58 ... 60 mm, 1 ... 3 mm
other dimensions on request
pressure difference up to 10 bar (145 psi)
temperature range room temperature, other conditions on request
test gas helium or hydrogen
detector measuring range up to \(10^{-9} \frac{mbar\:l}{s} \), optional with calibration

 

Your Request