Current research projects

Image Refrigerants, lubricants and mixtures
Image Humidifier System for High-Purity Gases
Image All-in-one device for freeze-drying and production of biomaterial
Image Helium extraction from natural gas
Image Software for technical building equipment
Image Micro fluidic expansion valve
Image Combined building and system simulation
Image Software modules
Image Heat2Power
Image Preformance measurements of heat exchangers
Image Innovative Parahydrogen Generator Based on Magnets
Image Tensile and compression testing
Image Tribological investigations of oil-refrigerant-material-systems
Image Filter Tests
Image Overall System Optimization of Refrigeration Plant Systems for Energy Transition and Climate Protection
Image Innovative Manufacturing Technologies for Cryosorption Systems

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Investigation of material-dependent parameters

Industry and R&D

Gunar Schroeder

+49-351-4081-5129

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

 


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Further Projects - Research and Development

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Reduction of primary noise sources of fans

...using numerical and experimental methods with contra-rotating axial fan

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Micro fluidic expansion valve

for increasing of the efficiency of small and compact cooling units

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Hydrogen and methane testing field at the ILK

Simultaneously pressures up to 1,000 bar, temperatures down to –253°C

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Low noise and non metallic liquid-helium cryostat

Low-noise Magnetic Field Cryostat for SQUID-Applications

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Cryostats, Non-Metallic and Metallic

position indenpendent, highest endurance, tiltable for liquid helium and liquid nitrogen