| The idea of using a form of reversed turbine is as old as the development of the reaction turbine (Sir Charles Parson obtained the first patent in 1884). In 1926 A. Griffith outlined the basic principles of his aerofoil theory of compressor and turbine design. The axial compressor has since been significantly developed and is the most predominant type used in gas turbines and especially aircraft turbojets today. The exceedingly complex flow within an axial-flow compressor is one reason why research and development proliferated over the years. When considering the actual monitoring of an axial compressor, not only shaft vibration due to unbalance is considered, but also the types of bearings, numbers of blades on each respective stage, etc., must be considered to monitor correctly. The standard monitoring sensor is the accelerometer, since it is important to monitor at high frequencies. Measurement of blade pass and bearing damage frequencies using an accelerometer requires dedicated signal analysis tools, like SED (selected envelope detection) and CPB (constant percentage bandwidth). B&K Vibro offers a range of monitoring solutions covering these requirements. Our monitoring solutions can adapt to any special requirements, through a variety of condition monitoring systems. | 
