Current research projects

Image Behavior of multiphase cryogenic fluids
Image Cold meter
Image Thermal engines
Image Software for test rigs
Image Corrosion inhibitor for ammonia absorption systems
Image Intelligent innovative power supply for superconducting coils
Image Ionocaloric cooling
Image Computational fluid dynamics CFD
Image Innovative Manufacturing Technologies for Cryosorption Systems
Image Investigation of coolants
Image Helium extraction from natural gas
Image High Capacity Pulse Tube Cooler
Image Swirl-free on the move...
Image Reduction of primary noise sources of fans
Image Refrigerants, lubricants and mixtures
Image Testing of mobile leak detectors according to DIN EN 14624

You are here:  Home /  Research and Development

Investigation of material-dependent parameters

Industry and R&D

Gunar Schroeder


Investigation of the permeation behavior

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

Further Projects - Research and Development