We provide on-site vibration measurement services to evaluate piping, machine and structural vibrations. We use high speed PC based data acquisition software with built in analysis tools together that can act as both a diagnostic tool and a data logging unit.
Where necessary we will fabricate adaptors and specialist devices to enable measurement in hard to reach and hard to access areas. With our standard arrangements we can measure vibration frequencies down to 2 Hz and vibration velocities up to 200 mm/sec. Measurement of lower frequencies and/or higher vibration velocities can be made, when required.
The signal processing software that we use has inbuilt fast fourier transform (FFT) functions that deliver instant live analysis of what is being measured. Such tools when used with in-built filter functions provide an excellent live diagnostic tools that is useful for tracking measurements when conditions, such as speed, change.
In the same way that the software that we use for the data analysis has inbuilt FFT functions, also built into the software are frequency filter functions. These frequency filter functions are software code that can be set up to give either a low pass, high pass, or notch filters effect and may be used to screen the signal to allow only the frequencies that are of interest to pass for analysis and subsequent display.
We can choose from the following software filters when taking our measurements;
Low-pass filter – low frequencies are passed, high frequencies are attenuated.
High-pass filter – high frequencies are passed, low frequencies are attenuated.
Band-pass filter – only frequencies in a frequency band are passed.
Notch filter – rejects just one specific frequency - an extreme band-stop filter.
There are many other type of software filter available, but these represent the ones that we most commonly use.
Equally as important as selecting the correct filtering setup is the selection of the correct sampling rate. Sampling rate is the rate at which the software will sample the output from the measurement instrument, such as a transducer.
If the sampling rate is too low then the shape of the signal being measured may be missed entirely, if the the rate is not high enough then the shape of the signal may be miss-interpreted leading to completely incorrect conclusions.
If the sampling rate is high enough then the shape of the signal being measured will be correctly tracked.
In the same way that the software must sample the signal with sufficient frequency, the measurement instrument itself must be able to respond to changes at a sufficient, or appropriate rate. Flo-Dyne will always match the response rate of the instrument to the requirements of the signal to be measured.
After processing the results we will produce a written report highlighting the main findings and pointing out any areas of concern, such as high vibration on your piping, machine or structure. Where we think that specific devices, or equipment may help, or are needed, we will make recommendations as to what action you might take.
