BS ISO 22423:2019 pdf free.Foil bearings一Performance testing of foil thrust bearings一Testing of static load capacity, bearing torque, friction coefficient and lifetime.
The primary purpose of the test is to measure and evaluate the static load capacity, bearing torque, friction coefficients and lifetime of a foil thrust bearing. These are the primary performance metrics of a foil thrust bearing as a mechanical element with specific dimensions. They are closely related to the performance of the mechanical systems in which foil thrust bearings are used.  The static load capacity of a foil thrust bearing should be tested, after the ambient pressure, temperature and humidity of the environment in which the bearing operates have reached a state of equilibrium. The bearing performance is determined by measuring the bearing torque and the rotational speed of the shaft. The take-off speed, which is the speed at which the runner floats on the top foil without making contact, should be determined. The bearing performance should be measured and compared at a rotational speed that is higher than the take-off speed.The bearing test apparatus should be designed to control the relative position of the bearing in relation to the runner. Excessive friction due to misalignment of the bearing can have a severe effect on the test results. It shall be avoided not only by maintaining a constant distance between the runner and the top foil, but also by preventing any disturbance that can affect the test results. A schematic illustration of the test apparatus is shown in Figure 1. The test load is applied by moving the loading plate to press against the runner, using a mechanical and/or pneumatic system. The equipment used to measure the bearing torque and static load capacity of the foil thrust bearings is installed as shown in Figure 1. Using the measurement system shown in Figure 1, the bearing torque and applied load are measured and calculated as explained in 7.3. The rotational speed of the shaft is determined using a rotational speed meter. A thermocouple is installed inside the bearing to measure the temperature of the surrounding air (gas). A thermocouple should be welded to the top foil surface to measure the surface temperature of the top foil (see Figure A.1 and Figure A.2). The bump foil, top foil and bearing plate should be designed and fabricated using materials appropriate for the intended use.BS ISO 22423 pdf download.