Evaluation of measurementmethods for vibrations in pipesystems.

Sammanfattning

Leakages cause by vibrations in refrigerant circuits can cause damage totheir direct surroundings and ecosystems. If compressor operation and thepiping’s eigenfrequency overlap this can cause excessive vibrations. It istherefore important to know what the eigenfrequencies of the pipe systemsare so these can be avoided during operation. The thesis reviews inputmethods and accelerometer locations that can be used to measureeigenfrequencies in the pipe systems during the design and productionphase. Two machines, three input methods and six triaxial accelerometerlocations were compared between each other. Modal hammers and sweepexcitations using the compressor were found to be effective and comparable.A minimum of two triaxial accelerometers were deemed necessary, thoughfour would be preferable. Further research could be done to find the cause ofthe difference between eigenfrequencies during operation and the offlinemachine.