ISO/TC 131/SC 8/WG 1 - Hydraulic component and system sound measurement

This document describes the procedure for determining the impedance characteristics of hydraulic components by means of measurements from pressure transducers mounted in a pipe. This document is applicable to passive components, irrespective of size, operating under steady-state conditions, over a frequency range from 10 Hz to 3 kHz.

ISO 10767-1:2015 establishes a test procedure for measuring the source flow ripple and source impedance of positive-displacement hydraulic pumps. It is applicable to all types of positive-displacement pumps operating under steady-state conditions, irrespective of size, provided that the pumping frequency is in the range from 50 Hz to 400Hz. Source flow ripple causes fluid borne vibration (pressure ripple) and then airborne noise from hydraulic systems. This procedure covers a frequency range and pressure range that have been found to cause many circuits to emit airborne noise which presents a major difficulty in design of hydraulic fluid power systems. Once the source flow ripple and source impedance of hydraulic fluid power pump are known, the pressure ripple generated by the pump in the fluid power system can be calculated by computer simulation using the known ripple propagation characteristics of the system components. As such, this part of ISO 10767 allows the design of low noise fluid power systems to be realized by establishing a uniform procedure for measuring and reporting the source flow ripple and the source impedance characteristics of hydraulic fluid power pumps. In ISO 10767-1:2015, calculation is made for blocked acoustic pressure ripple as an example of the pressure ripple. An explanation of the methodology and theoretical basis for this test procedure is given in Annex B. The test procedure is referred to here as the two pressures/two systems method. Ratings are obtained as follows: a) source flow ripple (in the standard "Norton" model) amplitude, in cubic meter per second[m3/s], and phase, in degree, over 10 individual harmonics of pumping frequency; b) source flow ripple (in the modified model) amplitude, in cubic meter per second [m3/s], and phase, in degree, over 10 individual harmonics of pumping frequency; and its time history wave form, c) source impedance amplitude, in Newton second per meter to the power of five [(Ns)/m5]., and phase, in degree, over 10 individual harmonics of pumping frequency; d) blocked acoustic pressure ripple, in MPa (1 MPa = 106 Pa) or in bar (1 bar = 105 Pa), over 10 individual harmonics of pumping frequency; and the RMS average of the pressure ripple harmonic f1 to f10.

ISO 16902-1:2003 establishes a test code based on ISO 9614-1 and ISO 9614-2 for determining the sound power levels of a hydraulic fluid power pump under controlled conditions of installation and operation. The sound power level will include sound power radiated by any piping within the measurement surface. ISO 16902-1:2003 is suitable for providing a basis for comparing the airborne noise levels of any type of pump that is normally used to convert rotary mechanical power to hydraulic fluid power, incorporating valves, solenoids, drive gears, couplings or any other auxiliary device normally fitted in service.

Establishes a test code describing procedures based on ISO 2204. Applies to all types of fluid power pumps. Guidelines for application are given in annex C. This second edition cancels and replaces the first edition (1979). Annexes C and D are for information only.

Establishes a test code describing procedures based on ISO 2204. Applies to all types of fluid power motors. Guidelines for application are given in annex C. This second edition cancels and replaces the first edition (1984). Annexes C and D are for information only.

This part closely follows the methods described in the two other parts, but allows the use of alternative pump mounting and drive configurations which are simpler and cheaper to implement in an anechoic chamber. May also be applied to test motors.

ISO 15086-3:2008 describes the procedure for the determination of the impedance characteristics of hydraulic components, by means of measurements from pressure transducers mounted in a pipe. ISO 15086-3:2008 is applicable to passive components, irrespective of size, operating under steady-state conditions, over a frequency range from 10 Hz to 3 kHz.

Specifies a precision method for the determination of pressure ripple levels and source impedance generated in hydraulic fluid power systems and components by positive-displacement hydraulic pumps.