Method and system for evaluating and monitoring hydraulic pump noise levels

A method for determining fluidborne noise characteristics of a fluid power pump, said pump being incorporated into a testing system comprising means for determining a rotational speed of the pump, a reference pipe fluidly connected to a discharge of said pump, more than two pressure sensors disposed within the reference pipe at predetermined spacings from each other and the pump discharge, said system further comprising first and second loading valves and a calculating and analysis assembly, said loading valves being selectively and alternatingly actuated to pressurize fluid contained in the system, said calculating and analysis assembly receives signals from said pressure sensors and said speed determining means, comprising the steps of:

• a) activating the pump to force fluid through the reference pipe and the extension pipe;
• b) closing the first loading valve to establish a predetermined average pressure in the system;
• c) measuring the pressure using said pressure sensors and transmitting first pressure signals to said calculating and analysis assembly;
• d) calculating harmonic spectra for said first pressure signals;
• e) opening the first loading valve and closing the second loading valve to establish the predetermined average pressure in the system;
• f) measuring the pressure using said pressure sensors and transmitting second pressure signals to said calculating and analysis assembly;
• g) calculating harmonic spectra for said second pressure signals;
• h) calculating source flow ripple and internal impedance using sensed pressure together with known physical properties of the reference pipe and the fluid;
• and,
• i) calculating flow ripple level using said source flow ripple and internal impedance, said calculated flow ripple level corresponding to source fluidborne noise of the pump.