Suggested exercises and observations
1. Identify a hydraulic system in your company where you can safely measure its noise.
• Lookup or check the pump type and then find how many pumping elements it has from the manufacturer's catalogue. Calculate the fundamental frequency of the flow ripple.
• Calculate the wavelength of the fundamental frequency and check how this compares with the length of the first pipework after the pump.
• Measure the different airborne noise levels around the circuit to try to establish where the majority of the noise is being radiated from.
• Convert the airborne noise measurements into a frequency spectrum to establish which frequencies have the highest amplitudes and are probably the most significant.
• Use the frequency data to identify which components are generating the noise.