Current research projects

Reduction of primary noise sources of fans

Investigation according to DIN EN ISO 14903

3D - Air flow sensor

High Capacity Pulse Tube Cooler

Innovative Parahydrogen Generator Based on Magnets

Calibration leak for the water bath leak test

Behavior of multiphase cryogenic fluids

Micro heat exchangers in refrigeration

Lifetime prediction of hermetic compressor systems

Investigation of coolants

In-situ investigation concerning the swelling behaviour of polymer materials under elevated pressures and temperatures

Influenced melting point of water by magnetic field

All-in-one device for freeze-drying and production of biomaterial

Pulse-Tube-Refrigerator with sealed compressor

Micro fluidic expansion valve

Hydrogen and methane testing field at the ILK

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Tribological investigations of oil-refrigerant-material-systems

Dr.-Ing. Margrit Junk

+49-351-4081-5419

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Modified Almen-Wieland wear testing machine

The modified Almen-Wieland wear testing machine is used for the determination of the tribological properties of oil-refrigerant-bearing-systems under mixed friction conditions. The interaction of lubricants, additives, refrigerants and materials is tested. On the basis of these investigations refrigeration oils and materials could be preselected, but the tests can not substitute field test with refrigeration machines.

Principle

Two half bearings are pressed hydraulically against a test pin rotating horizontally in the lubricant.

The extreme pressure failure, i. e. the load bearing capacity of oil, is determined by increasing continuously or stepwise the test load until seizure of pin and bearing occurs and the pin breaks. The coefficient of friction and the wear are determined with constant (low) load applied during a prescribed test time.

Bearing geometries (left: half bearings with Falex geometry with the same dimensions of the prism as the original Falex bearings (ASTM D 3233); right: Almen-Wieland half bearings).

Examples of adapted Almen-Wieland bearings (from left: Aluminum, plastic, copper or copper coating, DLC coating on steel).

Specialties

Hermetic test cell, which allows testing with refrigerant pressures up to 10 bar.
Thermostated test cell for a defined lubricant temperature.
Continuous record of fest force, turning moment, pressure of refrigerant, temperature and wear.
Use of both Almen-Wieland and half bearings with Falex geometry (dimensions of the V-block than the original Falex bearings according to ASTM D 3233).
Adaption of the tribological system by choosing materials of test pins and half bearings.

Our services

Evaluation of lubricant-refrigerant-material-systems by load bearing capacity of lubricant (extreme pressure failure load), coefficient of friction, wear, changes of lubricant
Evaluation of tribological systems after changing lubricants, refrigerants or bearing materials in order to minimize expensive field tests
Failure analysis