Vibration Measurement Tools
Stork Diagnostic Services has two systems to perform vibration measurements
With the CSI portable spectrum analyzers and the multi-channel real-time analyzers of Bently Nevada, Stork Diagnostic Services is able to carry out the measurements below at short notice anywhere in the world in order to demonstrate the dynamic behavior of your installation.
Portable Spectrum analyzer
This data collector performs and records vibration measurements on various sorts of rotating equipment. The measurements can be sub-divided into 3 categories on the basis of the customer's wishes:
A one-time only measurement is performed shortly after an overhaul or new construction.
These measurements are performed periodically, in which slight rises can be noticed at an early stage.
These measurements are performed in the event of deviating behavior of the installation in order to identify the cause within a short time. Considering the short time needed to prepare this equipment, we are adequately able to perform vibration measurements at our clients’ premises.
This spectrum analyzer can detect the errors/ defects below:
- Gear damage
- Bearing defects, sub-divided into:
- inner ring damage
- outer ring damage
- roller elements damage
- cage fractures
- Alignment errors
- Looseness and play
- Imbalance (including on-site balancing)
- Resonance areas (using impact test)
A possible cause determined during the measurements is diskussed with the client, and Stork Gears & Services may take direct action. Any further analysis needed can be carried out at short notice and recorded in a report.
Multi-channel real-time analyzer
The multi-channel real time analyzer is used to determine the dynamic behavior of your turbo machinery simultaneously with several housing vibration, axle displacement recorders and key phasers.
Several of the data presentation techniques, which can be used to give a correct analysis, are briefly described below:
Orbit or time-based graphs
Give the actual vibration signal in time. These plots give information about the phase, unfiltered amplitude, frequency and form of the dynamic movement of the axis.
Used to plot variables such as vibrations, pressure and temperature against time. Parameter change can be an early indication of possible defects in your installation.
Radial axis position graphs
Show the average radial axis displacement in the two dimensional plane. Changes in axis position indicate possible changing forces on the axis, e.g. as a result of alignment errors or process forces or indicate wear of the white metal.
Bode and polar graphs
Can show amplitude and phase of the filtered signal combined. These graphs are used to visualize lateral resonance frequencies. The results can indicate how good a system is suppressed by the passing of lateral resonance.
Several frequency spectra are plotted against speed in these graphs. These 3-dimensional presentations are used to observe changes in the frequency spectrum during a start-up and/or run-out.